The philosophical concept of geological time was developed in the 18th century by Scottish geologist James Hutton;[2][3] his "system of the habitable Earth" was a deistic mechanism keeping the world eternally suitable for humans.[4] The modern concept entails huge changes over the age of the Earth which has been determined to be, after a long and complex history of developments, around 4.55billion years.[5]
James Hutton based his view of deep time on a form of geochemistry that had developed in Scotland and Scandinavia from the 1750s onward.[6] As mathematician John Playfair, one of Hutton's friends and colleagues in the Scottish Enlightenment, remarked upon seeing the strata of the angular unconformity at Siccar Point with Hutton and James Hall in June 1788, "the mind seemed to grow giddy by looking so far into the abyss of time".[7][8]
Early geologists such as Nicolas Steno and Horace Bénédict de Saussure had developed ideas of geological strata forming from water through chemical processes, which Abraham Gottlob Werner developed into a theory known as Neptunism, envisaging the slow crystallisation of minerals in the ancient oceans of the Earth to form rock. Hutton's innovative 1785 theory, based on Plutonism, visualised an endless cyclical process of rocks forming under the sea, being uplifted and tilted, then eroded to form new strata under the sea. In 1788 the sight of Hutton's Unconformity at Siccar Point convinced Playfair and Hall of this extremely slow cycle, and in that same year Hutton memorably wrote "we find no vestige of a beginning, no prospect of an end".[9][10]
Other scientists such as Georges Cuvier put forward ideas of past ages, and geologists such as Adam Sedgwick incorporated Werner's ideas into concepts of catastrophism; Sedgwick inspired his university student Charles Darwin to exclaim "What a capital hand is Sedgewick [sic] for drawing large cheques upon the Bank of Time!".[11] In a competing theory, Charles Lyell in his Principles of Geology (1830–1833) developed Hutton's comprehension of endless deep time as a crucial scientific concept into uniformitarianism. As a young naturalist and geological theorist, Darwin studied the successive volumes of Lyell's book exhaustively during the Beagle survey voyage in the 1830s, before beginning to theorise about evolution.
Physicist Gregory Benford addresses the concept in Deep Time: How Humanity Communicates Across Millennia (1999), as does paleontologist and Nature editor Henry Gee in In Search of Deep Time: Beyond the Fossil Record to a New History of Life (2001)[12][13]Stephen Jay Gould's Time's Arrow, Time's Cycle (1987) also deals in large part with the evolution of the concept.
In Time's Arrow, Time's Cycle, Gould cited one of the metaphors McPhee used in explaining the concept of deep time:
Consider the Earth's history as the old measure of the English yard, the distance from the King's nose to the tip of his outstretched hand. One stroke of a nail file on his middle finger erases human history.[1]
In this illustration of the Big History the unit Ga ("giga-annum") has been chosen to bring the different periods and events into graspable numbers.
Concepts similar to geologic time were recognized in the 11th century by the Persian geologist and polymath Avicenna,[14] and by the Chinese naturalist and polymath Shen Kuo.[15] The Roman Catholic theologian Thomas Berry explored spiritual implications of the concept of deep time. Berry proposes that a deep understanding of the history and functioning of the evolving universe is a necessary inspiration and guide for our own effective functioning as individuals and as a species. This view has greatly influenced the development of deep ecology and ecophilosophy. The experiential nature of the experience of deep time has also greatly influenced the work of Joanna Macy.
H. G. Wells and Julian Huxley regarded the difficulties of coping with the concept of deep time as exaggerated:
"The use of different scales is simply a matter of practice," they said in The Science of Life (1929). "We very soon get used to maps, though they are constructed on scales down to a hundred-millionth of natural size ... to grasp geological time all that is needed is to stick tight to some magnitude which shall be the unit on the new and magnified scale—a million years is probably the most convenient—to grasp its meaning once and for all by an effort of imagination, and then to think of all passage of geological time in terms of this unit."[16]
Rance, Hugh (1999). "Hutton's unconformities"(PDF). Historical Geology: The Present is the Key to the Past. QCC Press. Archived from the original(PDF) on 2008-12-03. Retrieved 2008-10-20.
McPhee, John (1998). Annals of the Former World. New York: Farrar, Straus and Giroux.
Repcheck, Jack (2003). "Chapters 2 and 5". The Man Who Found Time: James Hutton and the Discovery of the Earth's Antiquity. Cambridge: Perseus Books. ISBN0-7382-0692-X.
Rossi, Paolo (1984). The Dark Abyss of Time: The History of the Earth and the History of Nations from Hooke to Vico, tr. by Lydia Cochrane, Chicago: University of Chicago Press, pp.338, ISBN0226728358.
Sir Charles Lyell, 1st Baronet, was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth's history. He is best known today for his association with Charles Darwin and as the author of Principles of Geology (1830–33), which presented to a wide public audience the idea that the earth was shaped by the same natural processes still in operation today, operating at similar intensities. The philosopher William Whewell dubbed this gradualistic view "uniformitarianism" and contrasted it with catastrophism, which had been championed by Georges Cuvier and was better accepted in Europe. The combination of evidence and eloquence in Principles convinced a wide range of readers of the significance of "deep time" for understanding the earth and environment.
Geology is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science.
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy and geochronology. It is used primarily by Earth scientists to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardised international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely define global chronostratigraphic units of the International Chronostratigraphic Chart (ICC) that are used to define divisions of geologic time. The chronostratigraphic divisions are in turn used to define geochronologic units.
James Hutton was a Scottish geologist, agriculturalist, chemical manufacturer, naturalist and physician. Often referred to as the "Father of Modern Geology," he played a key role in establishing geology as a modern science.
Uniformitarianism, also known as the Doctrine of Uniformity or the Uniformitarian Principle, is the assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in the past and apply everywhere in the universe. It refers to invariance in the metaphysical principles underpinning science, such as the constancy of cause and effect throughout space-time, but has also been used to describe spatiotemporal invariance of physical laws. Though an unprovable postulate that cannot be verified using the scientific method, some consider that uniformitarianism should be a required first principle in scientific research. Other scientists disagree and consider that nature is not absolutely uniform, even though it does exhibit certain regularities.
Timeline of geology
Historical geology or palaeogeology is a discipline that uses the principles and methods of geology to reconstruct the geological history of Earth. Historical geology examines the vastness of geologic time, measured in billions of years, and investigates changes in the Earth, gradual and sudden, over this deep time. It focuses on geological processes, such as plate tectonics, that have changed the Earth's surface and subsurface over time and the use of methods including stratigraphy, structural geology, paleontology, and sedimentology to tell the sequence of these events. It also focuses on the evolution of life during different time periods in the geologic time scale.
Old Red Sandstone, abbreviated ORS, is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the eastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the paleocontinent of Euramerica (Laurussia). In Britain it is a lithostratigraphic unit to which stratigraphers accord supergroup status and which is of considerable importance to early paleontology. The presence of Old in the name is to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain.
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in Berwickshire in 1788, both in Scotland.
Flood geology is a pseudoscientific attempt to interpret and reconcile geological features of the Earth in accordance with a literal belief in the Genesis flood narrative, the flood myth in the Hebrew Bible. In the early 19th century, diluvial geologists hypothesized that specific surface features provided evidence of a worldwide flood which had followed earlier geological eras; after further investigation they agreed that these features resulted from local floods or from glaciers. In the 20th century, young-Earth creationists revived flood geology as an overarching concept in their opposition to evolution, assuming a recent six-day Creation and cataclysmic geological changes during the biblical flood, and incorporating creationist explanations of the sequences of rock strata.
Sir James Hall of Dunglass, 4th Baronet FRS FRSE was a Scottish geologist and geophysicist. He was a Member of Parliament for St. Michael's borough 1807–1812.
Stephen Edelston Toulmin was a British philosopher, author, and educator. Influenced by Ludwig Wittgenstein, Toulmin devoted his works to the analysis of moral reasoning. Throughout his writings, he sought to develop practical arguments which can be used effectively in evaluating the ethics behind moral issues. His works were later found useful in the field of rhetoric for analyzing rhetorical arguments. The Toulmin model of argumentation, a diagram containing six interrelated components used for analyzing arguments, and published in his 1958 book The Uses of Argument, was considered his most influential work, particularly in the field of rhetoric and communication, and in computer science.
Of the many unconformities (gaps) observed in geological strata, the term Great Unconformity is frequently applied to either the unconformity observed by James Hutton in 1787 at Siccar Point in Scotland, or that observed by John Wesley Powell in the Grand Canyon in 1869. Both instances are exceptional examples of where the contacts between sedimentary strata and either sedimentary or crystalline strata of greatly different ages, origins, and structure represent periods of geologic time sufficiently long to raise great mountains and then erode them away.
Cockburnspath is a village in Berwickshire in the Scottish Borders. It lies near the North Sea coast between Berwick-upon-Tweed and Dunbar. Cockburnspath is the eastern terminus of the Southern Upland Way as well as the northern terminus of the Berwickshire Coastal Path. At the nearby village of Cove, there is a small fishing harbour.
Relative dating is the science of determining the relative order of past events, without necessarily determining their absolute age. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another. Prior to the discovery of radiometric dating in the early 20th century, which provided a means of absolute dating, archaeologists and geologists used relative dating to determine ages of materials. Though relative dating can only determine the sequential order in which a series of events occurred, not when they occurred, it remains a useful technique. Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
Siccar Point is a rocky promontory in the county of Berwickshire on the east coast of Scotland. It is famous in the history of geology for Hutton's Unconformity found in 1788, which James Hutton regarded as conclusive proof of his uniformitarian theory of geological development.
Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time is a 1987 history of geology by the paleontologist Stephen Jay Gould, in which the author offers a historical account of the conceptualization of Deep Time and uniformitarianism using the works of the English theologian Thomas Burnet, and the Scottish geologists James Hutton and Charles Lyell.
The history of geology is concerned with the development of the natural science of geology. Geology is the scientific study of the origin, history, and structure of the Earth.
Hutton's Unconformity is a name given to various notable geological sites in Scotland identified by the 18th-century Scottish geologist James Hutton as places where the junction between two types of rock formations can be seen. This geological phenomenon marks the location where rock formations created at different times and by different processes adjoin. For Hutton, such an unconformity provided evidence for his Plutonist theories of uniformitarianism and the age of Earth.
George Hoggart Toulmin was an English physician and writer who examined geology and planetary history. He was among the first to suggest that the earth was undergoing constant change, contrary to Aristotelian ideas of a planet unchanged since creation.
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