Knowledge Of Deserts and Playa Lakes – The Permian and Triassic Periods.
Peter Toghill’s Chapter 9 shows that these Periods lasted from 290 to 245 Ma and from 245 to 208 Ma respectively. In Britain, the rocks of these periods are dominated by red sandstones and the two systems together are often referred to as the New Red Sandstone in contrast to the Old Red Sandstone of earlier Devonian period. These two continental sequences are separated by the marine deltaic sequences of the Carboniferous, but in north-east Scotland they often succeed each other without any intervening Carboniferous and the boundary is then difficult to establish. The term Permian was introduced by Murchison in 1841, based on his studies around the city of Perm in Russia and the Triassic is based on a three-fold division of rocks in Germany set up by Alberti in 1834. However, the desert sandstones of Britain contrast with the marine sequences found in the present-day Mediterranean and Alpine areas which were part of the Tethys Ocean area (see Peter Toghill’s Chapter 10 below). Permian and Triassic fossils are either rare in Britain or, as in the dolomitic and saline Magnesium Limestone of north-east England, are difficult to relate to those of true marine areas. Animals and plants throughout the world were affected by a remarkable mass extinction at the end of the Permian which brought the Palaeozoic Era to an end. Many have heard of the destruction of the dinosaurs at the end of the Cretaceous at 65 Ma, but the Permian mass extinction, 245 Ma, was far greater, with 95% of known species having become extinct. Another mass extinction at the end of the Triassic saw the disappearance of 80% of the species then existing. Some small mammal-like reptiles survived this second mass extinction by burrowing in the ground, but had to wait another 180 million years to evolve into true mammals. The dinosaurs ruled as land vertebrates during the Mesozoic Era. Geologists now recognise a number of lesser mass extinctions in the last 500 million years.
As to the reasons for these extinctions, a number of suggestions have been made. Many relate to possible changes in the salinity of the seas and to the dominant aridity of the planet as Pangaea came together. Again the formation of Pangaea would have reduced plate tectonic activity at former ocean ridges while their reduction in sea levels world-wide and an associated reduction in shallow-water habitats while the existence of only one land-mass and increased competition for food might have been another factor. Again, the unusually large amounts of volcanic activity in the Permian caused great thicknesses of Permian basalt lavas in Siberia. Yet again such activity would have produced great quantities sulphur dioxide which would have caused acid rain, which could have destroyed vegetation and might have increased the acidity water bodies, including seas and oceans. Furthermore, collision with an asteroid which pierced the earth’s crust and penetrated molten rocks within the mantle, could have released pressure, thinned the crust over a hot spot, and thus produced volcanic activity deleterious to life in general. Peter Coghill notes at this point that the Earth is believed by some to be due for a twentieth century mass extinction by asteroid collision in October 2028, while we have actual evidence for a very large crater in Southern Mexico which may be of late Cretaceous age, and thus may have been the cause of the dinosaurs’ extinction.
However Peter Toghill provides a summary of Permian and Triassic Britain which is as follows. A harsh desert climate affected Britain during these 80 million years, only relieved by a maritime spell in the late Permian, and even this produced mainly saline rocks. Early Permian volcanic activity in south-west England and Southern Scotland was followed by the deposition of coarse Breccias in wadis and in scree slopes on the flanks of the intensely weathering Variscan highlands. These Breccias passed laterally into the Dune fields which covered vast areas of Britain, particularly in basins between the eroding highlands. These appear to have been formed in a Sahara-like desert at around 20-25 degrees North and deposited by a predominantly easterly wind. The dune sandstones pass east in the North Sea basin into red aeolian and coarse sandstones, and evaporites of the Rotliegendes. These are the source rocks for North Sea natural gas covered by later Permian evaporites, and the basin in which they were formed was probably below sea level. The invasion of the North Sea and Irish Sea basins by the saline Zechstein and Bakevellia Seas in the late Permian produced thick dolomitic carbonates and evaporites up to 1000m thick in the North Sea and north-east England and to a lesser extent in north-west England and the Irish Sea basin. These evaporites (halite and anhydrite mainly) were produced on sabkha salt flats around the edges of the Zechstein Sea, which at times dried up completely to produce potassium salts in the shimmering Playa lake basins surrounded by wind blasted desert landscapes. Five cycles of carbonates (Magnesium Limestone) followed by evaporites occur in north-east England and the North Sea. Between cycles, the Zechstein Sea was replenished from the north over barriers which were periodically flooded giving a ‘sea’ up to 300m deep in the subsiding North Sea basin. This cyclical flooding could have been caused by the end of the glaciation around the Gondwanaland south pole.
The Zechstein Sea had disappeared by the end of the Permian Period to be replaced in the Triassic by a subsiding North Sea basin and other fault-bounded rifts (grabens) in which thick continental deposits accumulated in the form of fluvial sandstones and playa deposits. Subsistence may have been as much as 2.5 km in some Triassic basins with corresponding uplift in the surrounding blocks or horsts. The early Triassic was dominated by a river system flowing from the south which deposited thick pebble beds and these deposits are followed by fluvial sandstones deposited by ephemeral rivers in a desert landscape. In the mid-Triassic a probable marine incursion from the south affected the English Midlands and the increased humidity produced new vegetation and a relatively abundant vertebrate fauna. During the later Triassic the whole of Britain became low desert plains over which thick carbonate-rich marls were formed in the playa lake basins with thick evaporites, mainly halite. These marls and marginal conglomerates blanked the desert highlands and sediments while rich vertebrate faunas fell into fissures in the dried out landscape. At the end of the Triassic, the Rhaetic marine transgression spread shallow waters of the marginal Tethys Ocean over the deserts of Britain to herald the start of the Jurassic Period. Britain, with its desert sediments is not the best place for the study of Permian and Triassic fossils, but elsewhere in the world the biggest mass extinction of all time, at the end of the Permian, caused major changes in flora and fauna with 95% of all species dying out, and marking the end of the Palaeozoic Era. The Triassic Period saw the start of the Mesozoic Era with its new reptile and early mammal groups and the fast evolving ammonites, although these were affected by another mass extinction at the end of the Triassic.
Article 65Knowledge Of One Super Continent, Pangaea-The Variscan Orogeny.
Peter Toghill’s Chapter 8 then shows that the closure of the Rheic Ocean at the end of the Carboniferous had profound effects in what is now Britain; but that it had an even wider impact globally in that it formed mountain ranges along the suture-line, including the Appalachians in what is now North America, various mountains in what is now north-west Africa and the Pyrenees and the Urals in what is now Europe, though no such mountains formed in Britain. The closure of this Ocean caused by a widening of the proto-Pacific resulted in there being only one supercontinent and one super-ocean by the end of the Carboniferous Period. Alfred Wegener called these Pangaea and Panthalassa (all land and all sea) and the current configuration of the continents and oceans is the result of the subsequent break-up of Pangaea from Triassic times onwards, and the subsequent movement of continents around the globe caused the appearance of three new oceans the Atlantic, Indian and Southern Oceans.
In Europe, the Varsican orogeny had definite phases, the last being late Carboniferous/Early Permian. Nearer to home the Varsican orogeny caused intense folding and deformation accompanied by slate grade metamorphism over south-west England, with no fold mountains being formed in contrast to those formed by the Caledonian orogeny. This contrast in turn has led to the suggestion that the Rheic Ocean closed mainly as a result of lateral fault movements rather than by head-on continental collision and its associated subduction. In particular, North America had to move a considerable distance laterally to make contact with north-west Africa, then part of Gondwanaland. Deformation in south-west England was followed by the intrusion of a granite batholith dated at 280-270 Ma (early Permian) while similar granite cuts had already deformed late Carboniferous Westphalian strata, so we see that this orogeny is post-Westphalian/pre-Permian.
To a lesser extent this orogeny also affected south Wales, the Mendips and the Forest of Dean where rocks are unmetamorphosed but can be observed to be intensely folded and affected by thrusts, as in Pembrokeshire. Again, north of St George’s Land (an island of red sandstone surrounded by shallow water shelf carbonates which separates north Wales from the English midlands), is also an area of faulting associated with the Varsican orogeny. By the end of the Carboniferous, this orogeny had caused uplift over the whole British area, which then lay within the arid hinterland of Wegener’s Pangaea, but there were no huge mountains, though elsewhere erosion of the Varsican highlands produced the sediment for the rocks of the next geological period, the Permian. Thereafter Peter Toghill provides more detail of the Varsican effects on south-west England, South Wales, the Forest of Dean, the Mendip hills, the Midlands, northern England and Scotland which need not concern us here.
Article 64Knowledge Of A New Continent – Britain Joined Together In The Devonian Period.
In his Chapter 6, Peter Toghill recalls that the Devonian Period saw remarkable contrasts in the geological development of Britain. In the south around the margins of the Rheic Ocean (now between Britain and Gondwana yet further to the south) marine Devonian sediments of Gondwana advanced northwards and merged into the sediments of Old Red Sandstone formed on the coastal plains of Wales and England, which were in turn receiving eroded sediments from the Caledonian mountains further to the north, these being eroded in an arid climate at 10-15 degrees south of the equator, but with periods of heavy rainfall causing flash floods. Over Scotland and the far north-east of England great thicknesses (up to 10 km) of Old Red Sandstone sediments accumulated in lakes within inter-montane basins, river valleys and flood plains. These lakes were by now supporting a wide range of primitive fish and land plants were colonising the surrounding marshy areas, and insects and arthropods were appearing on land and winged insects were taking to the air in the late Devonian Period. Meanwhile great thicknesses of lava (up to 3 km thick) were erupting from volcanoes in the Midland Valley area and the southern Highlands where cauldron subsistence occurred. This volcanic activity also expressed the ‘newer’ granites of Scotland which formed during the late Silurian and early Devonian Periods. There is also evidence that the Dalradian rocks metamorphosed during the early Ordovician and folded up as the Caledonian Mountains, and were not adjacent to the Midland Valley until the late Devonian as fragments are absent from the early Red Sandstone of the Midland Valley. Tear faulting along the Highland Boundary Fault could have brought the two areas together, and this fault together with the Great Glen Fault may be a terrane boundary. By the end of this period, the relief had become low enough for the Rheic Ocean to spread its shallow continental shelf seas over many areas at the start of the Carboniferous Period.
Again, in his Chapter 7: Tropical Seas And Coral Swamps -The Carboniferous Period, Peter Toghill recalls that the Carboniferous was so named in 1822 by Conybeare and Phillips, to include the coal-bearing (carbonaceous) strata in Britain; and that it is now estimated that this period of time lasted around 73 million years from 363 to 290 Ma. By the end of the Devonian, the Caledonian Mountains had been eroded down to lower altitudes and the Old Red Sandstone Continent was invaded by the shallow-self seas of the Rheic Ocean in a world-wide (eustatic) rise in sea level, caused by melting ice sheets around the south pole and/or by an increase in plate tectonic activity at mid-ocean ridges, the increased volume of such ridges displacing oceanic water onto adjacent continental shelves. The British area, 360 Ma was astride the equator and within a single continent within a single surrounding ocean but relatively close to an area of that Ocean now called the Tethys Sea which was warm and laying down tropical carbonates which now form the Carboniferous Limestone of the Pennines and other areas. Later these shallow seas were invaded by deltas formed by rivers flowing in from adjacent high ground. The sandstones formed in these deltas became Millstone Grits of the now northern English moors. The then humid climate and these deltas began to support swamps and tropical rain forests while these rapidly changing deltas, repeated inundations of the swamp areas, and the burial and decay of the luxuriant vegetation led to the eventual formation of numerous coal seams and of the now famous Coal Measures. This tripartite division into Carboniferous Limestone, Millstone Grit and Coal Measures can be seen over most of Britain, except in the south-west of England where deeper seas of the Rheic Ocean, produced a sequence of sandstones and mudstones, but without lime stones or conspicuous coal seams, while in Scotland, the division into Carboniferous Limestone and Millstone Grit is also less obvious and volcanic lavas and ashes are common.
During the Carboniferous, marine life continued to evolve with goniatites (ancestors of ammonites) being useful as zone fossils, with corals and brachiopods being common in early limestones, and with non-marine bivalves being useful for dating the Coal Measures. Land plants evolved to provide large trees which provided the Coal Measures. Amphibians and early reptiles evolved in humid forests and spiders and giant flying insects were features of the dense vegetation. Thereafter, a major cooling occurred with glaciation over the continents of Gondwanaland which then included the south pole, perhaps because the plant growth of the Carboniferous had removed significant amounts of carbon dioxide from the global atmosphere. Thereafter, Peter Toghill’s Chapter 7 provides further details of the Carboniferous Period which is sub-divided into the Dinantian Series which roughly equates to the Limestone, the Namurian to the Millstone Grit and the Westphalian to the Coal Measures, while it is unlikely that rocks of the Stephanian occur anywhere in Britain. However, while the details of this subdivision need not concern us here, Peter Toghill explains them under the subheads, the stratigraphical framework, the Carboniferous rock sequences of Britain, Devon and Cornwall, the south-west province, the Millstone Grit and Coal Measures, North Wales, The English Midlands, The Pennines and northern England, and Scotland, before summarising all of it as follows.
The Carboniferous Period, 363 -290 Ma, saw an initial spreading of a warm and shallow tropical sea over the eroded remnants of the Caledonian Mountains and the Old Sandstone Continent. This sea deposited Carboniferous Limestone over many parts of Britain, but in the northern Pennines, limestones are part of cyclical sequences which also contain clastic sediments caused by rapid sea-level changes, while in south-west England, deeper Rheic Ocean sediments without limestones form the Carboniferous Culm Measures. Again, in Scotland the early Carboniferous lagoonal limestones and fluvial sandstones also contain great thicknesses of basaltic lavas, and this volcanicity continued throughout the Carboniferous. Yet again, the early Carboniferous seas were invaded by rivers and deltas forming the Millstone Grit during the middle of the period, while during the later Carboniferous these supported luxuriant swamps and rain forests, while these deltas and their swamps were repeatedly covered by marine and lagoonal sediments caused by rapid changes in sea level. The thus buried peat deposits quickly decayed to form coal seams between the sandstones and shales of the Coal Measures. Towards the end of the period, the Variscan orogeny (see later) caused the now British area to rise above sea level and the change from a humid to an arid climate caused the formation of continental sediments.
Article 63Knowledge Of Coral Reefs, Graptolites And A Closing Ocean – The Silurian Period.
In his Chapter 4, Peter Toghill reviews our knowledge of the coral reefs and graptolites associated with the final episodes of marine sedimentation on either side of the Iapetus Ocean before it finally closed at the end of the period. Although subduction took place on both sides, much of the closure may have been caused by lateral shearing movements. Volcanic rocks are rare in the Silurian sequences, only occurring in South Wales (Pembrokeshire) and the Mendip Hills. However, bentonite volcanic ashes occur throughout the sequences on both sides of the Ocean, and in Llandovery Epoch, rocks of the Moffat area and make up 10% of the black shale sequences. On both sides of the closing Ocean, early Silurian (Llandovery) transgressions occurred on the shelf areas to be followed by shallow-water deposits (with corral reefs in the English Midlands) and these passed laterally into deep water turbidite environments with great thicknesses of greywakes and thin condensed sequences of anoxic black shales full of graptolites. The final infilling of the marine areas was followed by a continental collision as the newly formed continent of Avalonia and Baltica collided with Laurentia at around 20 degrees South (Chapter 5). The resulting Caledonian fold mountains covered most of Britain and heralded a continental phase of deposition, the Old Red Sandstone of the Devonian Period.
His Chapter 5: The Himalayas of North-West Britain – The Caledonian Orogeny, reviews the geological conditions after the Iapetus Ocean had closed during the late Silurian Epoch, by which time, the Caledonian Mountains formed along the suture line between Laurentia, Baltica and Avalonia, and rose to heights comparable to the Himalayas prior to being eroded to the current heights of the Scottish uplands, while the Rheic Ocean began to open to become what is now the Atlantic Ocean. This Chapter also describes collage collisions and terranes which arise because ocean floors are not usually simple structures comprising oceanic crust plus sediment. They may contain oceanic islands, sea mounts and plateaux, small continental fragments called microcontinents, and volcanic island arcs, all of which are called terranes, and many fold-mountains are complex structures including various terranes welded onto the edge of continental margins. This type of mountain building is often called collage tectonics because of the wide variety of terranes involved. This Chapter goes on to describe island arcs and accretionary prisms. As an oceanic plate is subducted, sediment may be taken down into the subduction zone, or it may be sliced off by the over-riding plate and added to it as a series of fault slices. The build-up of these slices with each one under-thrusting those formed earlier will build up a mass of faulted sedimentary rocks called an accretion prism. The prism may form in a fore-arc basin between the trench and the arc margin and eventually the whole island arc and accretion prism will be welded onto the continental margin as part of the fold structure as the ocean closes and the continents collide. The Southern Uplands of Scotland are the site of an ancient accretionary prism.
This Chapter also describes the Caledonian orogeny or epoch of mountain building, named after Scotland, where evidence for such mountain-building is well exposed. This episode includes a number of orogenic events which span the period from the early Ordovician to the early Devonian, an interval of 100 million years. But, though the whole orogeny took this long, the main activities were early Ordovician and late Silurian, a timescale compatible with the formation of the Himalayas which started to form 30 million years ago. The various movements were all caused by subduction zones on either side of the Iapetus Ocean which started in the early Ordovician and ended in the late Silurian, during which time southern Britain moved from a position near to the Antarctic Circle at 60 degrees South to around 20 degrees South, a distance of around 4500 km in 100 million years. Thus all of the Iapetus Ocean crust was subducted and destroyed in 100 million years at the rate of 4.5 cm per year, a similar rate to that measured in the Pacific Ocean at present, but the rate was probably more rapid, perhaps 7.5 cm per year from the late Ordovician to the Wenlock Epoch of the Silurian. During the Caledonian orogeny fold mountains of Himalayan proportions, as evidenced by the deep rock structure and fold amplitudes now exposed, were formed over Scotland and north-west Britain. The number of rocks thus metamorphosed to the highest grades, subsequently became the sediment source for later systems. In general terms, the intensity of earth movements decreases as one moves south over the British area. Areas such as the Lake District and North Wales do not show the intense folding seen in the Scottish Highlands.
In this Chapter 5, Peter Toghill then reviews our knowledge of the main episodes of the Caledonian orogeny under the headings, Grampian orogeny, igneous intrusions, chemical composition, Dalradian rocks, sediments, metamorphism, southern Scotland, the Lake District and other regions of England and of Wales from the Early Ordovician to the Late Silurian, during which time the British area was part of a huge continent straddling the equator called the Old Red Sandstone Continent. The rapid erosion of the Caledonian mountains provided the sediment for the Old Red Sandstone of the succeeding Devonian period and the final suturing of the continental masses which came together to form this new continent took place during the early Devonian, and Caledonian Granites of northern Britain are of this age and mark this event. This is my summary of Peter Toghill’s Chapter 5. He didn’t provide one.
Article 62Knowledge Of The Cambrian, Ordovician, And Silurian Periods.
In his Chapter 2, Animals In Abundance – The Cambrian Period, Peter Toghill summarises our knowledge of what is now the British Isles at a time when it consisted of two areas that were up to 7000 km apart on either side of the widening Iapetus Ocean before coming together again as this Ocean closed; that this ocean did widen, is indicated by the lack of andesitic volcanicity in any of the marine sequences; that life in Cambrian times existed in shallow-shelf areas on either side of this ocean; but that its width resulted in faunal provinces; and that the exceptional preservation of fossils suggests a greater variety of Cambrian life forms than we often find fossilised. In his Chapter 3: Volcanoes Of The Iapetus Ocean–Ordovician Period, he summarises our knowledge that this period contains great thicknesses of volcanic rocks (particularly andesites); that these indicate the continued but erratic closure of the Iapetus Ocean with subduction zones on either side; that while southern Britain moved steadily northwards covering a distance of 3000 km during the Ordovician from near the Antarctic Circle to around 30 degrees South, Scotland moved only a little from its equatorial latitudes. On the Scottish continental shelf shallow-water sediments and old oceanic crust merged south into deeper water greywackes and black shales while this northern margin of the Iapetus was affected by the Ordovician Grampian orogeny, which folded up the Grampian Highlands and caused high-grade metamorphism while on the southern margin of the Iapetus, huge volcanic islands erupted vast thicknesses of Ordovician lavas and ashes, interbedded with richly fossiliferous deep- and shallow-water sediments; that some animals were entombed by volcanic ash falls; that the Welsh and Lake District basins merged south into a shelf which occupied parts of the Welsh borders; and that the southern shoreline of the Iapetus is traceable through Shropshire.
Article 61Further To The Dethronement Of Belief By Knowledge.
With my Article 60, having reviewed the geological knowledge contained in the Introduction to Peter Toghill’s Book, I now relate this Section of Articles to his successive Chapter headings.
In his Chapter 1: Britain During The Precambrian Period, Peter Toghill observes that Britain’s oldest rocks are difficult to unravel because of the amount of deformation and metamorphism which they have undergone; that rocks of this Period were initially thought to be devoid of fossils and the Precambrian/Cambrian boundary was initially drawn at the base of the first rock sequences to contain fossils of abundant and varied life forms. However, he notes that we now have rare but widespread knowledge of marine plants and soft-bodied animals within the Precambrian strata, and we may eventually find therein the ancestors of the abundant hard-shelled life-forms of the subsequent Cambrian period; that the Precambrian stretches over 4000 million years from the origin of the Earth’s crust at 4600 Ma (million years ago) to the start of the Cambrian at 544 Ma; that the rarity of Precambrian fossils means that we cannot divide up this huge period as we can the Cambrian and later periods; that there is, however, a division into an older almost wholly metamorphic sequence called the Archaean (older than 2500 Ma) and a younger Proterozoic subdivision which contains a good deal of sedimentary rock and some marine fossils; and that the metamorphic Archaean rocks form the basement to all continents; but that they became visible on the surface where erosion and earth movement resulted in their exposure
He recalls that Britain’s oldest rocks are in north-west Scotland, from the south-eastern corner of Skye to Cape Wrath on the mainland; that they also occur extensively on the outer Hebridean islands of Harris and Lewis and as outcrops on the inner islands of Tiree, Coll, Iona and Islay; that Some of these Lewisian gneisses are Cambrian and others are Proterozoic; that in 1994, the age of one of these mainland gneisses was measured as of 3300 Ma; but that later work suggests that the oldest gneisses are of 2900–2750 Ma. Again, he recalls that the Archaean rocks found in Canada have been dated at 4000 Ma, the oldest rocks yet found. Again, he suggests that it is worth going to north-west Scotland to stand on and touch its rocks and to consider what the original basalt would have been like before it was metamorphosed to gneiss at around 3000 Ma. He recalls that geologists now consider that at the time when continents were being built, the Earth’s atmosphere contained no oxygen, at which point, I note that the earliest living things must have been photosynthesising single-cell plant forms. From this point onwards, I want my readers to know that unless I note otherwise, I am gratefully quoting Peter Toghill’s book: I am not a geologist. I am a physical chemist quoting a geologist to exemplify the benefits of knowledge over belief and counter-belief, unless such beliefs are hypotheses for reality-evaluation to further knowledge, either positive or negative, as in my campaign for knowledge to replace belief wherever possible.
The first and oldest unconformity which we come across in Britain is that separating the Lewisian gneiss in north-west Scotland from the Torridon Sandstone Group. The sandstones are of late pre-Cambrian (Proterozoic) age and have been dated at around 1000-700 Ma. This red sandstone appears to consist of river and lake deposits and indicates an arid climate close to the equator while measurement of their ancient magnetic fields indicates that they were deposited at 15 degrees North. These remarkable mountains of north-west Scotland, including Suilven and Canisp are formed of great terraces of these sandstones and from their slopes one is really looking at an exhumed pre-Cambrian landscape, which was inundated by the sea at the start of the Cambrian period at around 544 Ma and here we find our next unconformity with the white Cambrian sandstones, the Eribol Quartzite, resting on eroded Torridon Sandstone around loch Assynt. Again, these Cambrian Quartzites are followed by sandstones which have trilobites in them, the first abundant marine organism, and these are followed by tropical limestones (Durness limestones) which continue into the Ordovician. Thus, this plate-tectonic evidence indicates that this whole area of north-west Scotland was part of the eastern seaboard of what is now North America, an area which geologists call Laurentia, while it was south of the equator, while a new ocean, the Iapetus Ocean, was opening up under the influence of its developing mid-ocean ridge, and while what was to become the rest of the British Isles (including Eira) was moving away from it, while attached to the other side of the then opening ocean towards a subduction zone beyond 60 degrees South.
Scotland, east of the then opening Iapetus Ocean consists of the Northern Highlands, an area between the Moine Thrust and the Great Glen Fault, which is occupied by a 10 km thick rock sequence of Precambrian Sandstones and shales metamorphosed to schists and other rocks called the Moine Schists or the Moine Supergroup. These are intensely deformed, with slices of Lewisian Gneiss within them in places. These have been dated at between 1200 and 870 Ma and were metamorphosed around 1000 Ma, at 800 Ma and again around 460 Ma, and these strata are intensely folded. The sediments from which the Moine Schists have been formed may in places be lateral equivalents of the Torridon Sandstone Group. Folding and metamorphism depend on subduction zones and seafloor spreading, but here we have little evidence of ancient oceans, only of sediments formed in relatively shallow seas. However, most geologists look for comparable sediments in North America and Greenland (Laurentia) rather than further south in Scotland. South of this area, we cross the Great Glen Fault and enter the Grampian Highlands and encounter large tracts of mainly metamorphic rocks, this time called the Dalriadian Schists or the Dalriadian Supergroup. Towards the top of this sequence are found rare Cambrian and Ordovician fossils in a sequence which in part is equivalent to the Cambrian shallow water sequences of the far north-west.
This Supergroup comprises a very thick (up to 24 km) sequence of originally varied sedimentary rocks now largely metamorphosed to slates and schists. However, the grade of metamorphism decreases south towards the Highland Boundary Fault and towards the top of the sequence. Again, however, the effects of two later episodes of mountain building make it difficult to understand all local sequences. These rocks have been shown to follow on top of Moine Schists around the great Glen Fault, and are not older than 850 Ma. They accumulated on a shallow shelf, with stromatolite (algal) limestones now occurring on Islay. This shelf migrated north-west by the early Cambrian at 540 Ma, while the overlying Argyle Group contains at its base a remarkable sequence of beds indicating a late Precambrian glaciation – the famous Port Askaig Tillite (a tillite is the name given to an ancient glacial deposit produced by an advancing glacier and left behind when it retreats (otherwise known as glacial moraine). This glacial sequence contains evidence for over forty separate ice advances. Even more remarkable is the magnetic evidence that this glaciation occurred within 10-15 degrees of the equator within a sequence of shallow water calcium-magnesium carbonates. This Precambrian glaciation, dated around 600 Ma may be unique in that it affected all latitudes: there is evidence for it from other parts of the world. The boulder clays, thickest on Islay at 75 m, contain large boulders and appear to have been formed by a grounded ice sheet in a shallow sea. Similar deposits in Scandinavia show evidence of movement from the south, as do the Scottish deposits, but as we shall see, they were both connected before being separated by a deep and widening Sea.
Above the glacial deposits, we find a further 20 km thickness of Dalradian rocks within Argyle (9 km) and Southern Highland Groups (11 km) many of which are metamorphosed. These later sediments are very thick and show evidence of initially being formed on a rapidly subsiding shelf. They include sandstones like the Jura Quartzite, which is 5000 m thick, as well as thin limestones. Later on, the deposits show evidence of a much deeper ocean basin. A famous granite at Ben Vuirich intrudes the Argyle Group and is dated at 590 Ma, so we know the tillites are older than this, while recent work around the tillites has provided evidence for the earliest metazoan animals, possibly marine worms, while within 8 km above the tillites we find a sequence of submarine basalt lavas, the Tayvallich Volcanics dated at 594 Ma. These lavas occur above the Tayvallich limestone on the Argyle coast south of Oban and may be associated with seafloor spreading and a new ocean forming between Scotland and Scandinavia. This subsiding ocean basin then received a further 11 km of sediment in the later Dalradian Group, the highest limestone beds of which contain Middle Cambrian trilobites, so we know that the widening of this ocean basin went on into the Cambrian Period. The opening and closing of this Iapetus Ocean belongs to the Cambrian, Ordovician and Silurian Periods.
However, the Pre-Cambrian rocks in England and Wales only cover small areas compared to Scotland and rather than including Peter Toghill’s account of them here, I simply refer to the Summary with which he concludes the first Chapter of the book to which I am referring. Thus, he summarises by saying that we have now completed our look at Britain’s oldest rocks. In Scotland we have seen huge areas of Precambrian rocks in which the story has with difficulty been unravelled because of the amount deformation and metamorphism; that nonetheless it has been possible to see the development of sedimentary basins on the edge of the Laurentian supercontinent; that these basins were situated in the tropics and yet were affected by a glacial episode at 600 Ma; that during the late Precambrian the amount of sediment being deposited in the ocean basins was very great; that this continued into the Cambrian; that the basins were then subjected to the Grampian orogeny and folded up and metamorphosed during the early Ordovician; but that we cannot see the southern limit of this metamorphosed and folded area, as it is buried under younger rocks to the south but we can see the north-western edge of the fold mountains where the Moine Thrust pushes the metamorphic area north-west over the unaltered Torridonian and Cambrian of the far north-west; that in England and Wales we see small areas (inliers) of Precambrian rocks peeping out from the younger rocks where the story is of a poorly formed metamorphic basement overlain with young Precambrian sediments and volcanic rocks formed within an ocean basin with volcanic island arcs deformed by the Cadomian orogeny at the end of the Precambrian. 5/7/21.
Article 60Belief De-Throned By Knowledge.
Having recognised in Articles 58 and 59 that knowledge is currently subjugated by belief to the extent of being publishable only through the mouths of fictitious characters in the form of novels, I now draw my readers’ attention to a further example of this subjugation provided bythe publisher’s disclaimer which appears in the book The Geology of Britainby Peter Toghill re-published by Airlife Publishing in 2012. This disclaimer is that ‘the information in this book is true and complete to the best of our knowledge’; but that ‘all recommendations are made without any guarantee on the part of the Publisher, who also disclaims any liability incurred in connection with the use of this data or specific details’. Given that some of its diagrams are those of Course S 26, Historical Geology, of the Open University, this disclaimer astonishes me, and causes me to wonder (rhetorically) whether such graduates in geology reproduce such knowledge only to obtain their degrees, and disclaim it, and retain beliefs counter to it, thereafter.
Be that as it may, I now use the above book to demonstrate how geology uses the demonstrable knowledge of physicochemical science to replace nineteenth century biblical belief in a young, 4000 year old, Earth with the demonstrable knowledge that the Earth is very old, in fact, millions of years old; that the early belief which assumed that every feature of the Earth’s surface was formed by catastrophic action or biblical flood was replaced by uniformitarianism in which the Earth’s surface changed immeasurably slowly; and that the processes which formed rocks and geological features in the past are still active today at the same slow rates; that the present is the key to the past; that we can explain all ancient features in terms of current processes; and that the recent discovery of plate tectonics now replaces all previous uniformitarian theories (beliefs). The introduction to this book recalls that James Hutton, a member of the Scottish Enlightenment, began to study geological features around Edinburgh and at Siccar point on the Berwickshire coast, where he observed what is now called an unconformity, a structural difference between two sedimentary rock sequences caused by a period of uplift and erosion between the formations of the two sequences. As of now, we know that such an unconformity is evidence of a long time interval. In the Siccar point case, it is about 50 million years. However, without knowing anything about such time intervals, Hutton recognised that one sequence had been laid down, hardened, folded and eroded before the next was laid down on top, and in looking at these exposures, he reported in 1788 that in terms of Earth history, he could see ‘no vestige of a beginning and no prospect of an end’, an observation which brings us to the recognition and measurement of geological timescales.
It was William Smith, often called the ‘father of stratigraphy, who while constructing canals in southern England in the early 1800s, observed that each layer of rock contained a distinct layer of fossils; and that strata could thus be recognised elsewhere by the fossils they contain. Thus, it became possible in the 1800s to recognise different levels in the enormous rock sequence covering Britain from the fossils they contained, and on this basis, observers such as William Smith, had enabled Smith to produce a geological map of England and Wales by 1815. Such observations, over the whole of Britain, led in turn to the sequence of rocks being recognised, with the oldest on the bottom and youngest on top, which on the basis of fossil content could be divided into a series of major units progressively called eras, periods/systems, and epochs/series of relative time, which were initially named the Palaeosoic, Mesozoic and Cainosoic, i.e. ancient, middle and new life, the three of them comprising the Phanerzoic. In regions of layered sedimentary rocks of sequential periods where folding has occurred, the sequence of layering could be determined without reference to the differing fossil content of the layers.
However, the chemical discovery of radioactivity and its application to geology in the twentieth century, enabled geologists to advance from relative to absolute ages, and thus to discover how old rocks actually are in terms of their formation millions of years ago. In simple terms, we know that when lava solidifies to rock, some grains contain a radioactive isotope of uranium which decays to a non-radioactive isotope of lead; that having measured the constant rate of this decay in the laboratory, we can measure the extent of its progress in our rock sample and thus determine the time interval since its solidification, the constant rate of decay being slow enough for its defined and measured half-life to be capable of measuring time lapses of thousands of millions of years, thus giving the radiometric date of origin, and the unit thus used is given the abbreviation Ma, for millions of years ago. Thus, the Cainozoic Era is now sub-divided into the Quaternary Period/ System which itself is further sub-divided into the Holocene Epoch/Series, (10,000 years ago) the Pleistocene Epoch/Series (2 Ma years ago), the Neogene Epoch/Series (24 Ma), and the Palaeogene Epoch/Series (65 Ma) both of which are further sub-divided to two and three Epochs/Series; while the Mesozoic Era is sub-divided into the Cretaceous (146 Ma), the Jurassic (208 Ma) the Triassic (245 Ma) Periods/Systems; and the Palaeozoic Era is sub-divided into the Permian (290 Ma), the Carboniferous (363 Ma), the Devonian (409 Ma), the Silurian (439 Ma), the Ordovician ( 510 Ma); and the Cambrian(544 Ma) Periods/Systems; while the Precambrian Era is subdivided into Proterozoic (1000 – 2500 Ma), the Archaean (2500 – 3800 Ma) and the Pre-Archaean, (4600 Ma and back to the Formation of Earth). Indeed all of the above Eras are further sub-divided into Epochs and Series, though these need not detain us here. However, before proceeding, we must differentiate the rock-types now classified as igneous, sedimentary and metamorphic.
The very first rocks on the Earth’s surface were formed from the cooling of molten solutions and are termed igneous. The molten material which nowadays comes from shallow depths in the Earth’s mantle, down to 60 kilometres, is called magma. This can come to the surface from a volcano in the form of lava, and when it cools, the resulting igneous rock is often of a chemical composition which we call basalt, good examples from the geological past in Britain can be seen on Mull and in the nearby Fingal’s Cave on the Isle of Staffa. Other types of lava include andesite (common in the Andes) and obsidian. Sometimes lava has already hardened in the volcanic vent and is subsequently thrown out as volcanic ash during volcanic explosions. This ash which is called Tuff if it is from an ancient explosion, can entomb whole areas, as it did at Pompeii. It can also be erupted as a dense incandescent gas cloud which flows down the mountain at great speed and causes great damage, as it did at the eruption in Martinique in 1903, thus killing over 30,000 people. The early stages of the eruption of Vesuvius in AD 79 (Pompeii) were probably of this type.
On the other hand, when areas of the Earth’s crust are exposed as land, and are eroded by the sea, or by rivers, wind or ice, the small particles thus formed are called sediment and this material can be transported away from the source and laid down in layers on the seabed, in lakes, in river estuaries or on land to give great thicknesses of sediment which over long periods of time can be hardened to form sedimentary rocks, which usually have an obvious layered structure. Again, such layered sedimentary rocks have been moved to create the sedimentary rocks of some of world’s highest mountains such as the Canadian Rockies in which the layered structure remains clearly visible. Again, some of the best known sedimentary rocks are sandstones which consist of relatively coarse particles, while shales and mudstones consist of finer clay particles, while limestones are calcareous sedimentary rocks made up of the shells of marine animals and plants with proportional precipitates of calcium carbonate. Indeed, some of the latter include whole fossilised reefs, indicative of their formation in sub-tropical latitudes.
At this point, we have to consider the mechanism by which all of this implied lateral movement is actually achieved, and which is known as plate tectonics. The earliest idea was that of continental drift put forward by Alfred Wegener in 1915, but it was not until the 1960s that an explanation of the mechanism of that drift became available. Since then, geologists have accepted that the Earth’s outer shell, down to around 100 km consists of a number of distinct regions which they now call plates; that these plates move independently of each other, driven by giant convection cells in Earth’s molten interior; that the boundaries of the plates, where they are in contact with each other, are lines of movement (tectonic activity) where one plate is over-riding or sliding past another, or where new molten material, in the form of basalt lava, is coming to the Earth’s surface; that the latter boundaries, now called constructive plate boundaries, occur at mid-ocean ridges where volcanic activity produces a constant conveyor belt of new oceanic crust on either side of the ridge to produce new ocean floor; that the new floor moves continents apart on either side of the ocean; that the constant supply of new ocean-floor would increase the size of the Earth, were the crust material not being dragged back into the Earth at corresponding destructive plate boundaries which take the form of deep ocean trenches which mark the route of these returns; that this process is called subduction to denote that one plate is descending below another; that such subduction zones are areas of intense earthquake and tectonic activity where the rocks are folded, faulted, altered (metamorphosed) and melted to form new igneous rocks; that the world’s major earthquakes and volcanoes are associated with subduction zones; but that some of the most intense earthquake activity occurs where one plate is sliding past another along major breaks in the crust called transform faults; that such boundaries are called conservative boundaries; that the best known is the San Andreas Fault in California; that fold mountains and volcanoes are also formed on the leading edge of the plate which is over-riding the other if it is of continental material; that this is happening in the Andes of South America; and that island arcs occur when the two colliding plates are both oceanic areas, as in the East Indies today; that sea-floor spreading is certainly driven by convection cells causing a ‘push’ effect at ocean ridges; but that widening is also caused by a pull’ effect as cold dense plates slide down subduction zones due to gravity; and finally that the process of sea-floor spreading which causes new oceans to form and grow, also leads to the destruction of older oceans; and that the end product of the latter process is that the two continents previously on either side of the old ocean, finally collide to form a huge fold-mountain chain as in today’s Himalayas.
The foregoing now brings us to the great breakthrough in plate tectonics of the 1960s which related sea-floor spreading to magnetic anomalies, and thus introduced a means of deducing the rate of such spreading and of the associated continental drift. This breakthrough came about from observing that that Earth’s magnetic field repeatedly reverses its polarity every few hundred thousand years or so; and that there are large intervals of time when the field was opposite to what it is today- when a compass needle would have pointed to the south magnetic pole; and that a study of basalt lavas dated by the radioactive method on land going back over four million years would produce a timescale for these reversals; that studies of ocean floor in the vicinity of mid-ocean ridges showed them to be entirely basalt and to have a striped pattern of magnetic anomalies symmetrical about the ridge axis with strengths of the field greater and less than the average and it was shown by Vine and Matthews in 1963, following work by Hess in 1960 that these stripes corresponded to normal and reversed polarity in the basalts of the ocean floor. Hess had suggested that basaltic ocean crust was newly created at ocean ridges, and a comparison of the striped pattern on either side of the ridge axis on the ocean floor showed it to be identical with the pattern found in basalt lavas found on land. Thus, by calculating how far a particular stripe was from the ocean ridge and knowing the age of this stripe from continental lavas, it was shown how far the stripe had moved in so many million years from the ridge from which it had originated. Thus, sea-floor spreading rates are known to vary from 2cm per year in the North Atlantic to 20cm per year in the North Pacific, these being the amounts of movement on either side of the ocean ridge.
Sea-floor spreading is the mechanism by which oceans widen and push continents apart. However, all ocean crust is eventually destroyed at subduction zones where it dives back down to the mantle. Hess suggested that mid-ocean ridges were ephemeral structures having a life of 200 – 300 million years; and in fact nowhere on the Earth today is there any ocean crust older than 200 million years- all earlier ocean crust having been destroyed by earlier subductions. However, evidence for oceans up to 500 million years old comes from marine sediments which have not been subducted, old volcanic island arcs, and rare pieces of oceanic crust, called ophiolites, which are preserved within continents. In addition, we can see how continents have moved through various latitudes and climates in the past, as these continents have been pushed around by sea-floor spreading within oceans long since destroyed. All of the effects of plate tectonics can be seen happening somewhere on Earth today. Where we see these effects in older rocks we can conclude that these areas were at plate boundaries in the past. Thus, in examining the geology of Britain, we can see for instance the great thicknesses of volcanic lavas and ashes of Snowdonia which were formed between 500 and 450 million years ago, these being the products of a destructive plate margin where an oceanic plate was subducted under another to form a series of volcanic islands as material melted at depth. The volcanic ashes often fell into the sea and entombed animals of the seabed, which are now found as fossils on the very summit of Snowdon, while a modern example is the volcanic island arc of the East Indies and the teeming life of its surrounding oceanic area. Again, by analysing the chemistry of rocks we can identify trace element differences between volcanic rocks from continental areas such as the Andes and those from oceanic areas such as the East Indies and by such means show that those from Snowdonia and the older lavas from Shropshire, the Wrekin, etc., are from island arcs while those from the Midland Valley of Scotland are of continental origin.
Yet again, we can show that the Great Glen Fault in Scotland may mark the site of an old conservative plate boundary where one plate slid past another around 400-350 million years ago and caused enormous earthquakes, analogous to the San Andreas Fault in California, where the Pacific plate is moving northwards by sliding past the North American plate and causing numerous earthquakes. Furthermore the old fold mountain chain which covers the Scottish Highlands is an example of an ancient continental collision around 400 Ma in closing an ancient ocean and folding mountains up to 8000m high in a process exactly like that which more recently raised the Himalayas when the India plate collided with Asia about 20 Ma with the closure of another ocean. Again, we see that the geological sequence in Britain shows evidence of rocks produced in a variety of climates from cold temperate, through sub-tropical to Sahara-like deserts and tropical rain forests; that instead of proposing widespread global climate changes in the past, we can simply say that Britain has drifted northwards during the last 500 million years from a position in the southern hemisphere with southern Britain near the Antarctic circle, across the equator and into the northern hemisphere to reach its present latitude around 50 Ma. Since then, movement following the birth of the Atlantic has been eastwards. Indeed, Britain probably spent 300 of these 500 million years in the tropics which explains its former coral reefs, coal generating forests and Sahara-like deserts.
However, the foregoing assumes that the Earth has usually had the same climatic conditions and temperature differences between the poles and the equator as it does now. Yet it appears that during the last 1000 million years the Earth has been warmer than it is today; but that during four particular periods there has been major cooling periods which produced Ice Ages; that we are now living in the most recent of these cooler periods; that it has been in effect for about two million years; that during this current period the Earth is cooler than usual; that the more normal condition is for there to be no ice at the poles and for sea levels to be correspondingly higher; and that during the colder periods, oceanic water is trapped in continental polar ice caps with sea levels being correspondingly lower; and that because of our position ne
Article 60: Belief Dethroned By Knowledge.
Having recognised in Articles 58 and 59 that knowledge is currently subjugated by belief to the extent of being publishable only through the mouths of fictitious characters in the form of novels, I now draw my readers’ attention to a further example of this subjugation provided bythe publisher’s disclaimer which appears in the book The Geology of Britainby Peter Toghill re-published by Airlife Publishing in 2012. This disclaimer is that ‘the information in this book is true and complete to the best of our knowledge’; but that ‘all recommendations are made without any guarantee on the part of the Publisher, who also disclaims any liability incurred in connection with the use of this data or specific details’. Given that some of its diagrams are those of Course S 26, Historical Geology, of the Open University, this disclaimer astonishes me, and causes me to wonder (rhetorically) whether such graduates in geology reproduce such knowledge only to obtain their degrees, and disclaim it, and retain beliefs counter to it, thereafter.
Be that as it may, I now use the above book to demonstrate how geology uses the demonstrable knowledge of physicochemical science to replace nineteenth century biblical belief in a young, 4000 year old, Earth with the demonstrable knowledge that the Earth is very old, in fact, millions of years old; that the early belief which assumed that every feature of the Earth’s surface was formed by catastrophic action or biblical flood was replaced by uniformitarianism in which the Earth’s surface changed immeasurably slowly; and that the processes which formed rocks and geological features in the past are still active today at the same slow rates; that the present is the key to the past; that we can explain all ancient features in terms of current processes; and that the recent discovery of plate tectonics now replaces all previous uniformitarian theories (beliefs). The Introduction to this book recalls that James Hutton, a member of the Scottish Enlightenment, began to study geological features around Edinburgh and at Siccar Point on the Berwickshire coast, where he observed what is now called an unconformity, a structural difference between two sedimentary rock sequences caused by a period of uplift and erosion between the formations of the two sequences. As of now, we know that such an unconformity is evidence of a long time interval. In the Siccar Point case, it is about 50 million years. However, without knowing anything about such time intervals, Hutton recognised that one sequence had been laid down, hardened, folded and eroded before the next was laid down on top, and in looking at these exposures, he reported in 1788 that in terms of Earth history, he could see ‘no vestige of a beginning and no prospect of an end’, an observation which brings us to the recognition and measurement of geological timescales.
It was William Smith, often called the ‘father of stratigraphy, who while constructing canals in southern England in the early 1800s, observed that each layer of rock contained a distinct layer of fossils; and that strata could thus be recognised elsewhere by the fossils they contain. Thus, it became possible in the 1800s to recognise different levels in the enormous rock sequence covering Britain from the fossils they contained, and on this basis, observers such as William Smith, had enabled Smith to produce a geological map of England and Wales by 1815. Such observations, over the whole of Britain, led in turn to the sequence of rocks being recognised, with the oldest on the bottom and youngest on top, which on the basis of fossil content could be divided into a series of major units progressively called eras, periods/systems, and epochs/series of relative time, which were initially named the Palaeosoic, Mesozoic and Cainosoic, i.e. ancient, middle and new life, the three of them comprising the Phanerzoic. In regions of layered sedimentary rocks of sequential periods where folding has occurred, the sequence of layering could be determined without reference to the differing fossil content of the layers.
However, the chemical discovery of radioactivity and its application to geology in the twentieth century, enabled geologists to advance from relative to absolute ages, and thus to discover how old rocks actually are in terms of their formation millions of years ago. In simple terms, we know that when lava solidifies to rock, some grains contain a radioactive isotope of uranium which decays to a non-radioactive isotope of lead; that having measured the constant rate of this decay in the laboratory, we can measure the extent of its progress in our rock sample and thus determine the time interval since its solidification, the constant rate of decay being slow enough for its defined and measured half-life to be capable of measuring time lapses of thousands of millions of years, thus giving the radiometric date of origin, and the unit thus used is given the abbreviation Ma, for millions of years ago. Thus, the Cainozoic Era is now sub-divided into the Quaternary Period/ System which itself is further sub-divided into the Holocene Epoch/Series, (10,000 years ago) the Pleistocene Epoch/Series (2 Ma years ago), the Neogene Epoch/Series (24 Ma), and the Palaeogene Epoch/Series (65 Ma) both of which are further sub-divided to two and three Epochs/Series; while the Mesozoic Era is sub-divided into the Cretaceous (146 Ma), the Jurassic (208 Ma) the Triassic (245 Ma) Periods/Systems; and the Palaeozoic Era is sub-divided into the Permian (290 Ma), the Carboniferous (363 Ma), the Devonian (409 Ma), the Silurian (439 Ma), the Ordovician ( 510 Ma); and the Cambrian(544 Ma) Periods/Systems; while the Precambrian Era is subdivided into Proterozoic (1000 – 2500 Ma), the Archaean (2500 – 3800 Ma) and the Pre-Archaean, (4600 Ma and back to the Formation of Earth). Indeed all of the above Eras are further sub-divided into Epochs and Series, though these need not detain us here. However, before proceeding, we must differentiate the rock-types now classified as igneous, sedimentary and metamorphic.
The very first rocks on the Earth’s surface were formed from the cooling of molten solutions and are termed igneous. The molten material which nowadays comes from shallow depths in the Earth’s mantle, down to 60 kilometres, is called magma. This can come to the surface from a volcano in the form of lava, and when it cools, the resulting igneous rock is often of a chemical composition which we call basalt, good examples from the geological past in Britain can be seen on Mull and in the nearby Fingal’s Cave on the Isle of Staffa. Other types of lava include andesite (common in the Andes) and obsidian. Sometimes lava has already hardened in the volcanic vent and is subsequently thrown out as volcanic ash during volcanic explosions. This ash which is called Tuff if it is from an ancient explosion, can entomb whole areas, as it did at Pompeii. It can also be erupted as a dense incandescent gas cloud which flows down the mountain at great speed and causes great damage, as it did at the eruption in Martinique in 1903, thus killing over 30,000 people. The early stages of the eruption of Vesuvius in AD 79 (Pompeii) were probably of this type.
On the other hand, when areas of the Earth’s crust are exposed as land, and are eroded by the sea, or by rivers, wind or ice, the small particles thus formed are called sediment and this material can be transported away from the source and laid down in layers on the seabed, in lakes, in river estuaries or on land to give great thicknesses of sediment which over long periods of time can be hardened to form sedimentary rocks, which usually have an obvious layered structure. Again, such layered sedimentary rocks have been moved to create the sedimentary rocks of some of world’s highest mountains such as the Canadian Rockies in which the layered structure remains clearly visible. Again, some of the best known sedimentary rocks are sandstones which consist of relatively coarse particles, while shales and mudstones consist of finer clay particles, while limestones are calcareous sedimentary rocks made up of the shells of marine animals and plants with proportional precipitates of calcium carbonate. Indeed, some of the latter include whole fossilised reefs, indicative of their formation in sub-tropical latitudes.
At this point, we have to consider the mechanism by which all of this implied lateral movement is actually achieved, and which is known as plate tectonics. The earliest idea was that of continental drift put forward by Alfred Wegener in 1915, but it was not until the 1960s that an explanation of the mechanism of that drift became available. Since then, geologists have accepted that the Earth’s outer shell, down to around 100 km consists of a number of distinct regions which they now call plates; that these plates move independently of each other, driven by giant convection cells in Earth’s molten interior; that the boundaries of the plates, where they are in contact with each other, are lines of movement (tectonic activity) where one plate is over-riding or sliding past another, or where new molten material, in the form of basalt lava, is coming to the Earth’s surface; that the latter boundaries, now called constructive plate boundaries, occur at mid-ocean ridges where volcanic activity produces a constant conveyor belt of new oceanic crust on either side of the ridge to produce new ocean floor; that the new floor moves continents apart on either side of the ocean; that the constant supply of new ocean-floor would increase the size of the Earth, were the crust material not being dragged back into the Earth at corresponding destructive plate boundaries which take the form of deep ocean trenches which mark the route of these returns; that this process is called subduction to denote that one plate is descending below another; that such subduction zones are areas of intense earthquake and tectonic activity where the rocks are folded, faulted, altered (metamorphosed) and melted to form new igneous rocks; that the world’s major earthquakes and volcanoes are associated with subduction zones; but that some of the most intense earthquake activity occurs where one plate is sliding past another along major breaks in the crust called transform faults; that such boundaries are called conservative boundaries; that the best known is the San Andreas Fault in California; that fold mountains and volcanoes are also formed on the leading edge of the plate which is over-riding the other if it is of continental material; that this is happening in the Andes of South America; and that island arcs occur when the two colliding plates are both oceanic areas, as in the East Indies today; that sea-floor spreading is certainly driven by convection cells causing a ‘push’ effect at ocean ridges; but that widening is also caused by a pull’ effect as cold dense plates slide down subduction zones due to gravity; and finally that the process of sea-floor spreading which causes new oceans to form and grow, also leads to the destruction of older oceans; and that the end product of the latter process is that the two continents previously on either side of the old ocean, finally collide to form a huge fold-mountain chain as in today’s Himalayas.
The foregoing now brings us to the great breakthrough in plate tectonics of the 1960s which related sea-floor spreading to magnetic anomalies, and thus introduced a means of deducing the rate of such spreading and of the associated continental drift. This breakthrough came about from observing that that Earth’s magnetic field repeatedly reverses its polarity every few hundred thousand years or so; and that there are large intervals of time when the field was opposite to what it is today- when a compass needle would have pointed to the south magnetic pole; and that a study of basalt lavas dated by the radioactive method on land going back over four million years would produce a timescale for these reversals; that studies of ocean floor in the vicinity of mid-ocean ridges showed them to be entirely basalt and to have a striped pattern of magnetic anomalies symmetrical about the ridge axis with strengths of the field greater and less than the average and it was shown by Vine and Matthews in 1963, following work by Hess in 1960 that these stripes corresponded to normal and reversed polarity in the basalts of the ocean floor. Hess had suggested that basaltic ocean crust was newly created at ocean ridges, and a comparison of the striped pattern on either side of the ridge axis on the ocean floor showed it to be identical with the pattern found in basalt lavas found on land. Thus, by calculating how far a particular stripe was from the ocean ridge and knowing the age of this stripe from continental lavas, it was shown how far the stripe had moved in so many million years from the ridge from which it had originated. Thus, sea-floor spreading rates are known to vary from 2cm per year in the North Atlantic to 20cm per year in the North Pacific, these being the amounts of movement on either side of the ocean ridge.
Sea-floor spreading is the mechanism by which oceans widen and push continents apart. However, all ocean crust is eventually destroyed at subduction zones where it dives back down to the mantle. Hess suggested that mid-ocean ridges were ephemeral structures having a life of 200 – 300 million years; and in fact nowhere on the Earth today is there any ocean crust older than 200 million years- all earlier ocean crust having been destroyed by earlier subductions. However, evidence for oceans up to 500 million years old comes from marine sediments which have not been subducted, old volcanic island arcs, and rare pieces of oceanic crust, called ophiolites, which are preserved within continents. In addition, we can see how continents have moved through various latitudes and climates in the past, as these continents have been pushed around by sea-floor spreading within oceans long since destroyed. All of the effects of plate tectonics can be seen happening somewhere on Earth today. Where we see these effects in older rocks we can conclude that these areas were at plate boundaries in the past. Thus, in examining the geology of Britain, we can see for instance the great thicknesses of volcanic lavas and ashes of Snowdonia which were formed between 500 and 450 million years ago, these being the products of a destructive plate margin where an oceanic plate was subducted under another to form a series of volcanic islands as material melted at depth. The volcanic ashes often fell into the sea and entombed animals of the seabed, which are now found as fossils on the very summit of Snowdon, while a modern example is the volcanic island arc of the East Indies and the teeming life of its surrounding oceanic area. Again, by analysing the chemistry of rocks we can identify trace element differences between volcanic rocks from continental areas such as the Andes and those from oceanic areas such as the East Indies and by such means show that those from Snowdonia and the older lavas from Shropshire, the Wrekin, etc., are from island arcs while those from the Midland Valley of Scotland are of continental origin.
Yet again, we can show that the Great Glen Fault in Scotland may mark the site of an old conservative plate boundary where one plate slid past another around 400-350 million years ago and caused enormous earthquakes, analogous to the San Andreas Fault in California, where the Pacific plate is moving northwards by sliding past the North American plate and causing numerous earthquakes. Furthermore the old fold mountain chain which covers the Scottish Highlands is an example of an ancient continental collision around 400 Ma in closing an ancient ocean and folding mountains up to 8000m high in a process exactly like that which more recently raised the Himalayas when the India plate collided with Asia about 20 Ma with the closure of another ocean. Again, we see that the geological sequence in Britain shows evidence of rocks produced in a variety of climates from cold temperate, through sub-tropical to Sahara-like deserts and tropical rain forests; that instead of proposing widespread global climate changes in the past, we can simply say that Britain has drifted northwards during the last 500 million years from a position in the southern hemisphere with southern Britain near the Antarctic circle, across the equator and into the northern hemisphere to reach its present latitude around 50 Ma. Since then, movement following the birth of the Atlantic has been eastwards. Indeed, Britain probably spent 300 of these 500 million years in the tropics which explains its former coral reefs, coal generating forests and Sahara-like deserts.
However, the foregoing assumes that the Earth has usually had the same climatic conditions and temperature differences between the poles and the equator as it does now. Yet it appears that during the last 1000 million years the Earth has been warmer than it is today; but that during four particular periods there has been major cooling periods which produced Ice Ages; that we are now living in the most recent of these cooler periods; that it has been in effect for about two million years; that during this current period the Earth is cooler than usual; that the more normal condition is for there to be no ice at the poles and for sea levels to be correspondingly higher; and that during the colder periods, oceanic water is trapped in continental polar ice caps with sea levels being correspondingly lower; and that because of our position near to plate-boundaries in the past, our differing latitudes, and the great variety of rock-types and structures which have resulted, we have been able to understand the fundamental principles of geology and to use plate tectonics to understand and explain past events.
At this point in time we recognise eleven plates, the Eurasian, the North American, the South American, the Scotia, the African, the Arabian, the Indian-Australian, the Philippine Sea, the Pacific, the Cocos, the Nazca, and the Antarctic. At this point, it is interesting to note that Scotland, north of the Great Glen was once on the edge of the North American plate while the rest of mainland Britain was on the edge of the Antarctic plate. 18/6/21
ar to plate-boundaries in the past, our differing latitudes, and the great variety of rock-types and structures which have resulted, we have been able to understand the fundamental principles of geology and to use plate tectonics to understand and explain past events.
At this point in time we recognise eleven plates, the Eurasian, the North American, the South American, the Scotia, the African, the Arabian, the Indian-Australian, the Philippine Sea, the Pacific, the Cocos, the Nazca, and the Antarctic. At this point, it is interesting to note that Scotland, north of the Great Glen was once on the edge of the North American plate while rest of mainland Britain was on the edge of the Antarctic plate. 18/6/21.
Article 59Hypocrites’ Isle
My next example of this clever technique of putting expressions of knowledge into the mouths of fictitious individuals in novels to bring such knowledge to the attention of the reading public was exemplified further for me by Hypocrites’ Isle by Ken McClure (cf Article 58), published by Polygon in 2008. This book opens with a quotation from Francois Rabelais, from Pantagruel, Book 4, Chapter LXIV. ‘Pantagruel then asked what sort of people dwelt in that damned island. They are, answered Xenomanes, all hypocrites, holy mountebanks, tumblers of beads, mumblers of ave marias, spiritual comedians, sham saints, hermits, all of them poor rogues who like the hermit of Longmont between Blaye and Bordeaux, live on alms given by passengers’.
Ken McClure’s book Hypocrites’ Isle then tells a fictitious story of how a graduate research student at Edinburgh University discovers how cancer cells can be destroyed in the laboratory by a process involving a product produced and investigated by a Swedish pharmaceutical company some twenty-five years previously as a possible cure for cancer, but which had failed to observe what he had now observed and which now opened the possibility that it could actually cure those suffering from cancer if further investigations were carried out; how he discovers that the company no longer manufactures this substance; that the patent has expired; that it cannot be re-invoked by the company; that it could be re-patented by a competitor company if the news of the student’s success were to be published in a scientific journal in the usual way; that consequently the originating company now wanted the student’s results to be suppressed; that the University authorities agreed to this suppression; that they preferred this suppression to the loss of further funding from the Swedish company; and that from this development the student concluded that money was more important to the company, and to the university authorities, than a cure for cancer; and that the sale of palliative non-cures was more lucrative in the long run than the sale of one-off cures in general; and that the former was the objective of the pharmaceutical industry rather than the latter.
However, this fictional presentation of the pharmaceutical industry is more incisive than the previous presentation of anthropogenic global warming (Article 58), in that this one is accompanied by an Author’s Note which I reproduce as follows. ‘Although a work of fiction, Hypocrites’ Isle is based on something that happened to me (Ken McClure) when I was a researcher in microbial genetics’. ‘I was working on the genes determining cell shape in the genus E. coli, when I stumbled across the reason why an old anti-biotic had failed in practice when, in the research lab, it had appeared to have great promise, and had been given an expensive launch by its manufacturer some twenty years before.’ ‘I had also discovered how it could be used to great effect if it were to be combined in a particular way with other drugs’. ‘My hope was that this new technique could be used to clear up a persistent, recurrent, urinary tract infection called pyelonephritis’. ‘This condition is nearly always caused by E. coli, and affects a great many people across the world, mainly women’. ‘Although not fatal, it often becomes chronic, and many women suffer from recurring infections throughout their lives’.
Ken McClure goes on to say, ‘I was naive in thinking that the drug company would be delighted’. However, ‘they didn’t want to know and I was later to discover that the anti-biotic in question was out of patent and the company no longer had the exclusive right to make it’. ‘Apart from that, it would have been difficult for them to relaunch a product which had already failed, and sales of their more recently developed drugs would have suffered’. ‘A more cynical view put to me at the time, was that chronic conditions are big cash-cows for the pharmaceutical industry, much more so than any condition they can clear up’. He goes on, ‘Not happy with the commercial view of things, I approached the university body which acted as an interface between academia and business’. ‘They were very excited at first, but became less enthusiastic when they learned that the new treatment did not involve any new compounds’. ‘They wanted something they could patent to protect the university’s interests’. ‘They thought it might be possible to patent the intellectual property of the idea and this was confirmed by lawyers, but in the end they pulled out, arguing that E. coli was a relatively soft pathogen and there were plenty of other drugs to treat it’. ‘I approached my employer at the time, the Medical Research Council, who had a similar body’. ‘They informed me that as I had already told the pharmaceutical company about my findings, it would actually be impossible for them to patent the idea, so they had no further interest’. ‘At no time did anyone think that just curing the disease was a good idea’: everyone I approached was primarily concerned with whether or not they could make money’. ‘My assertion that I just wanted to put my idea into practice cast me in the role of an ivory tower academic, who didn’t understand the real world’. Thus, spake Ken McClure!
Thus, in light of the content of my Articles 58 and 59, I now have to recognise that in addition to my recognition of the need to differentiate the knowledge/belief dichotomy, I also have to recognise that the ubiquitous reluctance to do so arises from money being just as easily be made from belief as from knowledge, if not easier; that this conclusion explains the ubiquitous failure of our species to adopt my newly definitive differentiation of the knowledge/belief dichotomy and with it those of truth/untruth, wisdom/folly, right/ wrong and good/bad in all of its policy-making since before and after Socrates first alluded to this difference over 2000 years ago; that with the help of the writings of Crichton and McClure, I and the readership of this website, might be able to correct this failure in the very near future; and that this was the objective of my third book, as it is of this website, and of my public campaign against belief-consensus, and for its replacement with debate-terminating conclusive whenever and wherever such is already available, or for the suspension of all belief until such corrective knowledge has been acquired by my newly definitive reality-evaluation of belief to positive or negative knowledge as exemplified throughout this website. 15/6/21.
Article 58State Of Fear.
Having published my book, The Rational Trinity: Imagination, Belief and Knowledge on the print on demand basis, because I had anticipated problems in otherwise obtaining a commercial publisher for its revolutionary differentiation of the knowledge/belief dichotomy, I have had these anticipated problems confirmed by my recent awareness of commercially published books by authors who have chosen to express beliefs counter to those currently accepable, through the mouths of fictitious characters in what are clearly novels, and thus commercially publishable as such. The first of these to come to my attention in this way was ‘State of Fear’ by Michael Crichton, published in paperback by Harper Collins in 2005, at which point I recalled having previously read ‘Hypocrites’ Isle’by Ken McClure, ‘the master of the thriller’ who adopted this approach in exposing ‘the desperate paradoxes of the medical research industry, the corruption of academia, the hidden politics of drug manufacture, and the chilling human tragedy of a system in which the cost of doing the right thing is sometimes too high’, and which was judged ‘scrupulously observed and completely persuasive’ by The Telegraph, while The Scotsman commented that ‘the most frightening thing is that he makes it all so believable’. At this point, I ask, how much more convincing would such books be, were their beliefs and counter-beliefs to be reality-evaluated for compliance or non-compliance with the experiential reality common to all, and which would thus convert them indisputably to positive or negative knowledge as explained and exemplified in my third book and in this website.
However, Michael Crichton’s clever mixture of fiction and fact, opens with an introduction which fictionalises that ‘in late 2003, at the Sustainable Earth Summit conference in Johannesburg, the Pacific island nation of Vanutu announced that it was preparing a lawsuit against the Environmental Protection Agency of the United States over global warming; that ‘Vanutu stood only a few metres above sea level, and the island’s eight thousand inhabitants were in danger of having to evacuate their country because of rising sea levels caused by global warming’; that ‘the United States, the largest economy in the world, was also the largest emitter of carbon dioxide and therefore the largest contributor to global warming’; that ‘the National Environmental Resource Fund, (NERF) an American activist group, announced that it would join forces with Vanutu in the lawsuit which was expected to be filed in the summer of 2004’; that ‘it was rumoured that wealthy philanthropist George Morton, who frequently backed environmental causes, would personally finance the suit, at an expected cost $8 million’; and that ‘since the suit would ultimately be heard by the sympathetic Ninth Syndicate in San Francisco, the litigation was awaited with some anticipation’. The book is thus a fictional account of how a major financial supporter of the NERF wishes to withdraw his support because he disapproves of an undercover/illegal plan of the Organisation of which he has become aware, which remains unknown to the reader until the closing stages of the book, and which, were I to reveal it here, would destroy a very good read for those who have yet to read it.
My purpose at present is to suggest that Michael Crichton, now deceased, probably did not believe in anthropogenic global warming. As to facts counter this belief, he cites them as appropriate to the development of his story with actual references to to scientific journals which appear as footnotes to the appropriate pages of the book, and he reproduces these references with his comments on each one, in a Bibliography at the end of the book. However, for what I assume to be the requirements of publishers in general, these comments treat these references as counter-contributions to a debate which has already concluded in favour of the now prevalent belief in anthropogenic global warming. Thus, while I conclude that he was a disbeliever in AGW and sought to encourage this disbelief in his readers, the book is a terrific read whatever the individual reader believes or disbelieves, and whatever the publishers believed or disbelieved when they accepted this book for publication in a form which permits the reader to believe or disbelieve in anthropogenic global warming, without committing the publisher one way or the other. 10/6/21.
Article 57The Politics of Catastrophe.
In a recent book, Doom, The politics of Catastrophe, Niall Ferguson catalogues possible sources of catastrophe. The flyleaf states in summary, that ‘disasters are difficult to predict; but that when they strike, we ought to better prepared than the Romans were when Vesuvius erupted or medieval Italians were when the Black Death struck; that we have science on our side after all; and that after all, the responses of many developed countries to the new pathogen from China were badly bungled. Why?’ To this question, the fly leaf responds that ‘while populist rulers performed poorly in the face of this pandemic, Niall Ferguson argues that more profound pathologies were at work – pathologies already visible in our responses to earlier disasters’; and that ‘drawing from multiple disciplines including economics and network science, Doom offers not just a history but a general theory of disasters, showing why our evermore bureaucratic and complex systems are getting worse at handling them’ and that ‘Doom is the lesson of history that the West needs to learn, if we want to tackle the next crisis better, and to avoid the ultimate doom of irreversible decline’. Again, the back of the dust cover offers the following ‘Acclaims For Niall Ferguson, ‘A great historian… Ferguson is master of all he surveys’,TheSpectator. ‘The most brilliant British historian of his generation’ The Times, Ferguson’sintellect and panache mean that his skilful revision of history will reverberate for years to come’ Guardian, A talented controversialist. He brings a wealth of historical knowledge to bear on big questions’ Independent, and Ferguson has a knack for making long-ago events as vivid and visceral as the evening news’The New York Times.
However, my response to this Niall Ferguson book is that it unconsciously demonstrates the rectitude of my contention that all crises and disasters arise from our willingness to act on belief rather than on knowledge; and that this willingness arises from our failure to differentiate knowledge from belief, wisdom from folly, truth from falsehood, right from wrong and good from bad, by evaluating their respective compliance or non-compliance with the cause-effect reality which our senses experience and which gives rise to out beliefs (hypotheses) in the first place, and which, if we are wise, we further evaluate to positive or negative knowledge by observing their compliance or non-compliance with this cause-effect reality of our experience; and that were we to do so, we would avoid or at least reduce all of the crises and disasters reviewed by Niall Ferguson in his failure to recognise, as do all other commentators, that the contention of belief and counter-belief is itself the source of all our crises and disasters, be they wars, pandemics, forest fires; or our tendency to build too close to geological fault-lines, volcanos etc.
However, before the third Section of this website has confirmed how transformative it would be, were all current belief-only policies to be replaced with knowledge-only alternatives, I want to recognise those few authors who have recognised the difficulty of publishing critiques of current practices without the benefit of my newly definitive differentiation of the knowledge/belief dichotomy and with it those of truth/falsehood, wisdom/folly, right/wrong and good bad, and who have sought to overcome this this difficulty by adopting the practice expressing their opposition to specific beliefs through the mouths of fictional characters in their recent novels. In addition, I will show that those non-scientists, such as Niall Ferguson, who cite science without recognising it to be knowledge acquired by the experimentation which isolates the hypothetical cause from all other possible causes in order to identify the actual cause, are now being accompanied by an increasing number of scientists who don’t always recognise the need for this experimentation derived confirmation of hypothetical belief to knowledge. 6/6/21.