How geology has changed in 350 years, with a snook to Creationists

From very early times people had observed and made use of the geological environment. Minerals have been mined for millennia and one of the earliest accounts of mining is to be found in Job 28.

1 “Surely there is a mine for silver, and a place for gold to be refined.
2 Iron is taken out of the earth, and copper is smelted from ore.
3 Miners put an end to darkness, and search out to the farthest bound the ore in gloom and deep darkness.
4 They open shafts in a valley away from human habitation; they are forgotten by travelers, they sway suspended, remote from people.
5 As for the earth, out of it comes bread; but underneath it is turned up as by fire.
6 Its stones are the place of sapphires, and its dust contains gold.
7 “That path no bird of prey knows, and the falcon’s eye has not seen it.
8 The proud wild animals have not trodden it; the lion has not passed over it.
9 “They put their hand to the flinty rock, and overturn mountains by the roots.
10 They cut out channels in the rocks, and their eyes see every precious thing.
11 The sources of the rivers they probe; hidden things they bring to light.
12 “But where shall wisdom be found? And where is the place of understanding?
13 Mortals do not know the way to it, and it is not found in the land of the living.

The sheer number of mines in the ancient world shows just how much practical knowledge of rocks and minerals there was. There is a mine for copper and base metals near Mt Sinai which dates back to 1400 BC, which may well have provided the metals, needed for the tabernacle. Old Testament Cosmology reflects its origin in 500-1000BC

Ancient-Hebrew-view-of-universe

Many Greeks and Romans observed natural phenomena and Pliny was the first vulcanologist to be killed by a volcano in 79 AD, when he was helping people to escape from the eruption of Vesuvius.

Today Creationists reject all geology and suggest bizarre alternatives but none as humorous as this one

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Out on a cycle ride pedalling over hills made of 330 my old Carboniferous limestone and smeared with Glacial Till some 20,000 years ago I saw this sign outside an Anglican church. It is both true and dishonest. Theories do change as this essay describes, but the purpose of the poster was to sow seeds of doubts and open the way fro Creationism.

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Try another thought experiment in the year 1650. You are interested in fossils, minerals and rocks and wonder how they all got there. You are very well–read and can read all the Latin works on minerals, but you want to get back to the beginning. So you read the Bible with creation in six days and an enormous deluge. As many had worked out the Biblical Chronologies, with Ussher’s Annales Veteris Testamenti published in 1656 as the most famous, it was thought that the age of the earth was to about six thousand years.

Jacobus_ussher

And then there was the Deluge. Most people in Europe were aware of the devastating effects of floods. They were intimately acquainted with flooding of the Severn and Trent in England, the Seine, Rhine and Danube on the continent, not to mention flash floods in hilly areas. Sudden floods could not only wash away river banks and property, they could also leave thick deposits of sand and silt. A primitive understanding of sandstones and silts would compare them to mud and sand and thus it was believed they were deposited by water.

What would you conclude? You would think that the earth was not very old, humans had been around about 6000 years and that the Flood had mashed up the earth’s surface and could well have laid down strata, just as you had seen by a river bank. You have ended up with a fairly typical Theory of the Earth of the late 17th Century, which were produced by the dozen.

As savants (I use the French word as many of these highly educated writers were not scholars in the usual sense of the word, as some were men of means, others university professors or in secular employment.) began to look at the earth and its rocks after 1660, the formed stones or fossils began to be studied in earnest. Any substance embedded in a rock was called a fossil, whether they are human artifacts, minerals or plant– or animal– like objects. These formed stones became a center of controversy in the late 17th Century. Some argued that they were impressions of dead animals or plants and others denied it. What is obvious to us was not at all obvious then, as no one would expect plants or even sea–shells to be turned into stone. It was contrary to commonsense and observation. By the end of the century most savants accepted the organic origin of formed stones, but that created another problem. How could one explain fossils found at high altitudes, say at 2,000 feet in the limestones of Northern England or many thousand feet high in the Alps? Something watery had to deposit them there and the obvious culprit was the Deluge.

So by 1700 most savants in Europe reckoned the earth to be thousands of years old – probably somewhat older than Ussher’s date of 4004BC – and that most rocks were laid down by the Flood. To make it more plausible, Whiston and Halley suggested that a passing comet affecting the oceans caused the Flood, thus giving a naturalistic twist to this scriptural geology. Therefore until nearly 1800 most early geologists followed a Flood Geology model as this made greatest scientific sense to them.

The progress of geology appears to us to be painfully slow. Until 1760 the 18th Century was not a very fruitful period for geology but observers added to the knowledge of the earth. After mid–century many savants throughout Europe turned their eyes away from the stars above to the rocks below. Often the story is told that it was the heroic efforts of a few men like Hutton and Lyell who argued for an ancient earth in the face of virulent opposition from the church. That has the same truth content as the flat–earth story, even when put forward by learned scholars from Cambridge or Berkeley. It is perfectly true that some Christians opposed geology but most did not.

It is difficult to say exactly who first argued for an ancient earth in the 18th century as scientists were arguing for it in many European countries from 1760 to 1800. Like many scientific discoveries it was a culmination of previous work and no one scientist should take all the credit. It was a cross–fertilizing, trans–European venture with significant workers including Whitehurst, Hutton

james-hutton-caraciture

and Smith from Britain, Buffon, Cuvier and Soulavie from France, de Saussure and de Luc from Switzerland and Werner and Blümenbach from Germany. There was considerable diversity between them, both in religious belief and scientific method. They differed on the age of the earth: de Luc and de Saussure favored an age of tens of thousands of years (MECs –Middle-aged Earth Creationists!) whereas Hutton, Buffon and Soulavie favored millions. However both of these views would be lethal to a young earth. Geologists were slowly piecing together very fragmentary evidence and there is no sense that any started from an assumption of an old earth in some kind of materialist opposition to the Christian Church. It would be truer to say that geologists started with young earth and flood geology assumptions and then changed them, as contrary evidence proved irresistible. A good example is Sir William Hamilton, plenipotentiary at Naples, who is best known to the British as the husband of Lord Nelson’s mistress, Emma. However before he married Emma in 1791 he carried out much research on Mt Vesuvius. He observed that in between many bands of lava was a band of burnt soil indicating sufficient time between volcanic eruptions elapsed to allow the formation of soil and vegetation. He concluded that the earth must be more than thousands of years old.

We move from Naples to Chamonix in the Alps. Henri de Saussure of Geneva was a great explorer of the Alps and the second to climb Mt Blanc. His Voyages dans les Alpes (1779-96) is a wonderful account of his explorations and geology. When he commenced his work he was convinced that the rocks in the heart of the Alps were those formed during the early stages of Creation. He began to question this as a result of his exploration of the Arve Valley from Geneva to Chamonix. This included ascending the precipitous Mt Buet (10,500ft) with a large barometer and Mt Blanc. Two places were of prime importance in convincing de Saussure of the earth’s vast age. First are the waterfalls at Nant d’Arpenaz, near Sallanches. Water plunges down a vertical cliff of over 1000 feet and the cliff is a synclinal fold of Mesozoic limestone rotated though 90 degrees. (Figure 3.) The second are vertical sediments (actually Ordovician) at Vallorcine 10 miles east of Chamonix. These were thought to be crystalline-like granite but de Saussure found rounded pebbles indicating water–erosion. Instead of crystalline “creation rocks” (i.e. those formed in the initial creation) followed by sediments, de Saussure now had older sediments underlying the newer sediments. He concluded that the earth had to be old but never speculated in print what the age could be and simply considered it to be “très vieille”.

Writers like de Saussure and Hamilton published their findings either in tomes or journals, which were widely read throughout Europe. During the last decades of the 18th Century the question was not whether the earth was considerably older than Ussher suggested, but whether its was millions of years old as Buffon, Fr Soulavie, Fr J. Needham (both Roman Catholic priests) and Hutton suggested or tens of thousands as de Luc and de Saussure posited. The choice was OEC or MEC!

So much for the age of the earth, but how were the rocks deposited? The proto–geologists of the 17th century were convinced of the major and, possibly, only cause – The Noachian Deluge. It is fashionable to make jest of this and to claim that this was the pernicious influence of the church. This is standard fare of the “pop” atheist but is rejected by any competent historian of geology. With Genesis as the only writing available, which spoke of the early story of the earth, it was almost inevitable that they should opt for the Flood. It made a tremendous amount of sense as no one had any inkling how old the earth was. The Flood could apparently explain how strata, which looked similar to river deposits, were formed and why fossils could be found on high ground. The realization of the true nature of fossils served to confirm this and thus until about 1830 the Flood was seen to be an important geological agent. Consequently, the many Theories of the Earth written in the 17th Century all emphasized that the strata with fossils were laid down by the Flood. As the 18th century wore on, several observers began to question it. In 1749 Buffon in his Histoire Naturelle questioned the flood arguments of Whiston, Woodward and Scheutzer and offended the theologians at the Parisian University of the Sorbonne. These theologians objected to Buffon minimizing the effect of the Flood rather than raising the age of the earth – a point which is often lost.

Towards the end of the 18th century some geologists, notably Hutton, ignored the Flood altogether. Others suggested the strata were deposited by  a succession of catastrophic floods, and that the Noachian Deluge was the last of many. After Lyell published his Principles of Geology in 1830, Whewell named Hutton, Fleming, Lyell and similar geologists Uniformitarians in distinction to the Catastrophists, who included George Cuvier, Jameson and many geologists on both sides of the Channel. Most notable in the 1820s were the English clergy –geologists Sedgwick, Henslow, Conybeare and Buckland who was reckoned to have believed in some fifty deluges! As a high proportion of strata (in today’s terms from the Cambrian to the Quaternary) was clearly deposited by water and contained marine fossils, multiple floods, or catastrophes, made sense. However by 1820 only the Quaternary deposits were regarded to be Noachian. As it turned out these were drift deposits formed during the Ice Age.

The differences of Uniformitarians and Catastrophists are often reduced to parody as if one group were reasonable scientists escaping the clutches of the churches and the other second–raters beholden to church dogma which insisted on the Flood. It is frequently claimed that Lyell enabled geologists to escape dogma and become free in their science, especially in regard to the age of the earth. This argument is wrong on several counts. First, all geologists sought to explain geological events by natural causes (even by comets causing floods) and by comparing present processes with what happened in the past, thus Catastrophists were uniformitarian in one sense. Secondly, both Uniformitarians and Catastrophists were equally convinced of the vast age of the earth. Thirdly, from 1780 to 1830 Catastrophists had made a larger contribution to geology than Uniformitarians, particularly on the Geological Column. And fourthly, many Uniformitarians, most notably the Reverend John Fleming were devout evangelicals.

So far, we have considered many aspects but not the historical order of strata, which geologists call the Geological Column. This is one of the most important interpretative constructs of all geology, but its origin even confuses many geologists. There are several principles behind its method. First there is the Principle of Superposition, which was grasped in the 1660s by Nils Steno, later a Roman Catholic Bishop. This simply states that in a pile what lies at the bottom was put there first and what lies on the top was put there last. Very obvious and very simple and inevitable because of Gravity. However the out–working of these principles is never easy because at times strata are folded or inverted. By 1790 i.e. before Cuvier and Smith

200px-william_smith_geologist

began to use fossils there was a rudimentary geological column with rocks in approximate order that gave us the Primary, Secondary and Tertiary strata in descending order of age. (diagram ex Laudun) The Primary rocks were mostly granites and gneisses and were thought to be the rocks of the original creation. (Remember that both Christians and Deists believed that God originally made the world.) These were overlaid by newer and newer rocks. It was relatively easy to work out a rough order where strata were more or less flat and folded rocks. Hutton was the first to work out The Principle of Cross–cutting Relationships and the occurrence of unconformities in the 1780s.

During the 18th Century many workers produced their tables of strata, but these remained rudimentary until the important breakthroughs of the 1790s. The German geologist Blümenbach worked out that animals and plants could go extinct – with great implications for the history of life. Also in that decade fossils were first used to work out the order of strata. The French say Cuvier and Brogniart were first with their work on the chalk (Cretaceous) around Paris, but the English claim priority with William Smith who mapped the limestones (Jurassic) around Bath. It is often portrayed that they used only fossils to work out the relative order of strata, but they could do this only because the strata were almost horizontal and the Principle of Superposition enabled them to work out the order of the strata in the first place. As they also noticed that certain fossils always appeared in the same order, they realized that the order of fossils was a historical sequence. If they then went somewhere else and found those fossils they could correlate them with those they had already found. By 1799 Smith had worked out the succession of strata from the Coal Measures (Pensylvanian) to the Chalk. This he improved in 1816, when his new Geological Column was essentially that of 1860 and today. (see Figures 4 and 5 ) In his work Smith was encouraged by three Anglican clergy – Warner, Richardson and Townsend. What is often not known is that in 1797 Smith believed all rocks were laid down at the same time, i.e. about 6000 years ago but by 1805 realised that the earth was ancient. With these breakthroughs using fossils the elucidation of the history of the earth and the Geological Column could begin in earnest. It is often claimed that the use of fossils in dating rocks and producing the Geological Column is a case of circular argument from evolution. As Cuvier and Brogniart were dogmatic anti–evolutionists and Smith knew nothing about it, that charge is falsified. Fossils are not absolutely necessary to elucidate the order of strata as I found when I mapped a large area of fossil–free Precambrian in South Africa, by working out which strata lay above another, and working out the displacement due to faults.

From then on geologists gradually began to work out the Geological Column and tried to work upwards and downwards from the Jurassic and Cretaceous. They used a mixture of the Principle of Superposition and the use of index fossils. By the 1820s they had worked out most of the strata from the Carboniferous (Mississipian and Pennsylvanian in the United States) to the top of the Cretaceous, but had problems with the Permo–Trias (New Red Sandstone) owing to the lack of fossils. What was above and below defied them. The newer strata – the Tertiary – did not contain easily identifiable stratigraphic units and the fossil contents of different layers seemed to merge into each other and contained some forms living today. In 1831 Adam Sedgwick

300px-Adam_Sedgwick

and Roderick Murchison began to work on what are now the Cambrian, Ordovician and Silurian rocks of Wales. Sedgwick worked on the Cambrian in Snowdonia where the strata contained few fossils and were heavily folded and thus relied more on the principle of superposition. Murchisons’s task was easier as he found more fossils and encountered less folding. He was also fortunate to have a Shropshire vicar the Reverend Thomas Lewis, a former pupil of Sedgwick, to direct him to sections passing down from the Old Red Sandstone (Devonian) to the older strata which he termed Silurian. Murchison, to his shame, never gave full recognition to Lewis. The work was slow and laborious and resulted in fractured relationships between Sedgwick and Murchison and was only completed after their deaths when Lapworth suggested the Ordovician to lie in between the Cambrian and Silurian. What is not widely known is just how many of the early 19th century geologists were devout Christians, including several evangelicals such as Sedgwick, Fleming, Lewis and Townsend.

By about 1850 the whole of the geological column was more or less worked out and it is almost identical to what we have today. (Figure 5.) The main differences are some name changes of stages and the recognition that parts of the Cambrian and Silurian are now Ordovician. The whole succession of life from the base of the Cambrian was also worked out. Up to then there had been little work on the Precambrian and much of that waited until the 20th Century. From reading this you may think that the Geological Column is of only local value as initially it was worked out in Britain and the European mainland. However, the same sequence was found throughout Europe and, given local variations, is the same throughout the world. I had its universal validity demonstrated to me while teaching geology for Wheaton College in the Black Hills. Almost all strata from the Precambrian to the Tertiary are present in a small area. Very quickly I could make sense of the geologic succession by comparison with British formations, as they were remarkably similar. Even the fossils were similar. I found the same comparison in the Grand Canyon the year before. By 1850 geology had come a long way in two hundred years, but no one had any idea of the real age of the earth. It would be correct to say that in the 17th Century geologists started with the assumption of a young rather than an old earth and during the 18th century were forced, by geological evidence to accept an old earth. Until 1910 there were many guestimates, both educated and uneducated, on the age of the earth. From the middle of the 18th century it was clear that the earth was more than a few thousands of years old, but how old was not known.

400px-Geo_time

The authors of the various Theories of the Earth reckoned the earth to be thousands of years old – older than Ussher suggested but not much. Two who broke loose from the Theories of the Earth were de Maillet and Buffon. Benoit de Maillet (1656-1738) was a French diplomat who wrote Telliamed: or conversations between an Indian philosopher and a French missionary in 1748. It was an odd work both accepting mermaids and that the earth to be over two billion years old. The second was Buffon, born as Georges-Louis Leclerc (1707-88), the Keeper of the Jardin du Roi in Paris. He published many volumes of Histoire Naturelle. Buffon also carried out experiments on the cooling of red-hot globes of iron and then applied his findings to the cooling of a globe the size of the earth and estimated the age of the earth to be about 75,000 years.  In unpublished manuscripts Buffon reckoned the earth to be 3 million years old.

By 1800 many thought that the age of the earth was millions of years, yet no precise figure could be given. Twenty years later, the eccentric British clerical-geologist William Buckland (1784-1856) was reckoning “millions of millions” of years.

buckland

There was no concerted attack by the church as most educated Christians happily accepted geologists’ findings, which was not surprising as many were clergy. When Darwin published The Origin of Species in 1859, the vast, but unspecified, age of the earth was as established as heliocentricity. The Reverend Samuel Haughton (1821-97), Geology Professor at Dublin and an ardent opponent of Natural Selection, suggested that 1,526 m.y.(million years) had passed since the beginning of the Cambrian, three times the present figure. That was too cavalier for William Thomson (later Lord Kelvin), who believed in the precision of physics. From 1855 Kelvin reckoned the age of the earth to be no more than 100 m.y. With the authority of physics against them, most geologists succumbed.

In the 1880s Kelvin reduced his estimates to about 24 m.y. and for a half-century from 1860, few geologists dared to suggest more than 100 m.y. for the age of the earth. In 1860, John Phillips (1800-74), nephew of William Smith and geology Professor at Oxford, suggested 96 m.y. He estimated that the rate of deposition today is one foot in 1,332 years. As the estimate of the thickness of fossiliferous strata was 72,000 ft, that made about 96 m.y. This date gave credence to Kelvin’s 1868 estimate of 100 m.y.  Though rates of deposition were very much guesses the thickness of strata in the various periods are good indication of the relative length of the periods. Despite this great disparity of estimates, the one agreement was that the age of the earth was to be measured in millions of years. This was shared by most Christians, including the evangelicals, whose ideas of time were included in the booklets published in 1910, entitled The Fundamentals.

While Kelvin was shrinking the age of the earth, the French physicist Henri Becquerel (1852-1908) discovered radioactivity in 1896. Radioactivity had two major implications for the age of the earth. The first was that radioactive decay created immense energy, thus negating Kelvin’s arguments for a cooling earth. The second was that radioactive elements could be used to measure time as they disintegrated at a fixed rate – known as their half-life.   In 1905 the English physicist John William Strutt, later Lord Rayleigh (1842-1919) showed that a mineral containing radium was 2 billion years old because of its helium content. In the same year Bertrand Boltwood suggested that Lead may be the end product of the decay of uranium and calculated the ages of 43 minerals from 400 to 2,200 my. The radiometric dating game had begun.

 

Arthur Holmes and the Age of the Earth

For the next fifty years the most innovative geologist on the dating-game (and on plate tectonics) was Arthur Holmes.

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He wrote many articles on geological time and several editions of a short, but profound book The Age of the Earth in 1913, 1927 (this edition cost sixpence) and 1937. In 1913 he based his work on three Uranium-Lead results from the Paleozoic. Combining this with the thickness of sediments, he estimated the base of the Cambrian to be 600m.y., remarkably close to present figures of 550m.y. Whatever flaws there were in his early work, they show remarkable geological insight. As time wore on the number of age determinations multiplied and is now almost infinite. A study of Holmes’s work over half a century (as carried out by Cherry Lewis) shows how an initially tentative scientific theory can be gradually supported by strong experimental data.

Initially Holmes reckoned the age of the earth to be under 2 billion years, but from 1946 this was seen to be nearer 4.6 billion, with the Cambrian commencing in about 550-590 m.y., with the lower estimate being accepted today. Despite the many refinements and explosion of methods and age determinations, this figure has remained the same for half a century. There are three basic methods of determining the age of the earth. The first is to date the oldest rocks on earth, as this will give a minimum age of the earth. The ages of the Amitsoq gneisses of Greenland, first “dated” by the Oxford geologist Stephen Moorbath and others in the early 1970s, have not yet been bettered.  The five methods used give an average of 3.65 billion years, with a variation of less than 0.1 b.y. either way, which is about 2%. Nearby the Banded Ironstones give ages of 3.8 b.y. These are for whole rocks and in the last ten years minute fragments of detrital Zircons in early Precambrian sediments have given ages up to 4.4 b.y. indicating that the grains may have been formed at that time yet deposited by water about 3 b.y. ago. That indicates that the earth had cooled to form a crust with 200 M.y. or so from the formation of this planet. The second are the ages of meteorites, which give ages between 4.5 and 4.7 b.y.  The second are the ages of meteorites, which give ages between 4.5 and 4.7 b.y. The third is more theoretical and is to determine “model lead ages” from the decay of uranium into lead for the Earth, Moon and meteorites. It was developed independently by Holmes and Houtermans in 1946. (For a more technical discussion read Dalrymple, The Age of the Earth.)

The greatest advance in the late 20th Century was the discovery of plate tectonics and its precursor continental drift. Though this came to be geological orthodoxy in the 1970s, Wegener, Holmes

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and du Toit were suggesting continental drift from the fit of continents in the 20s and 30s. Most significant was the matching–up of the geology of Africa and South America. To give an example, I worked in the Precambrian strata near the mouth of the Orange River in South Africa. When a geologist friend returned from Uruguay I was able to describe to him the Precambrian geology of Uruguay, without having been there or read a book on the subject. The discovery of subduction and ocean floor spreading turned old ideas of continental drift into a highly plausible theory. Plate tectonics has a superb explanatory power and explains so many geological riddles of the past. As a result it has come to be seen as the over–arching theory of geology and has unified the somewhat disparate geology of the last 200 years.

 

References;

Rudwick The Meaning of Fossils, 1972 London

Young, Davis, & Stearley; The Bible, Rocks and Time  IVP 2008

The Biblical Flood, 1995, Eerdmans

Roberts, M Evangelicals and Science 2008 Greenwood

  1. J. Gould, Time’s Arrow, Time’s Cycle, 1988 Viking

** A. Cutler, The Seashell on the Mountaintop, 2003. (A readable and superb biography of Steno, a 17th century geologist and anatomist.)

  1. Winchester, The Map that changed the World, 2001, Penguin (Readable, but anti-Christian)

 

Historical Box

Geologist                           Dates                                 Contribution                             Religion

Steno                               1638-1686                             Principle of superposition       RC Bishop

Ray                                 1627-1705                            Hints of older earth                   Minister

Buffon                            1707-1788                          Great age                                     Nominal RC

J-L Soulavie                1752-1813                             Great age                                    RC Priest

de Luc                         1727-1817                            Much geology                               devout Prot

Werner                       1749-1817                           Much geology                              ?prot?

Hutton                         1726-1797                         Unconformities etc                     Deist

Smith                           1769-1839                         Use of fossils                               anglican?

Cuvier                         1769-1832                          Fossils, strat,                                nom prot

Sedgwick                    1785-1873                          Cambrian etc                              Evang clergy

Buckland                     1784-1856                          fossils, ice age                          Anglican clergy

Lyell                            1797-1875                         Uniformitarianism                        Unitarian

Murchison                   1791-1871                          Silurian                                        nom Anglican

Thomson (Ld Kelvin) 1824-1907                   Physicist, age of earth                     Presbyterain

Holmes                        1890-1964                   Radiometric dating                            none

 

 

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