95-575: Gakkel Ridge Caldera , also known as Gakkel Caldera , is a Pleistocene volcanic caldera located on the Gakkel Ridge beneath the Arctic Ocean , off the northern coast of Siberia . It erupted approximately 1.1 million years ago, with an estimated eruptive volume of 3,000 km (720 cu mi). This eruption places it at VEI-8 on the Volcanic Explosivity Index , making it one of
190-459: A Middle Jurassic fossil of the early mammal Didelphis , Lyell told his father that "There was everything but man even as far back as the Oolite." Lyell inaccurately portrayed Lamarckism as a response to the fossil record, and said it was falsified by a lack of progress. He said in the second volume of Principles that the occurrence of this one fossil of the higher mammalia "in these ancient strata,
285-571: A "remarkable manifestation of creative Power" as creating each species separately. He countered Lamarck's views by rejecting continued cooling of the earth in favour of "a fluctuating cycle", a long-term steady-state geohistory as proposed by James Hutton . The fragmentary fossil record already showed "a high class of fishes, close to reptiles" in the Carboniferous period which he called "the first Zoological era", and quadrupeds could also have existed then. In November 1827, after William Broderip found
380-585: A change from low-amplitude glacial cycles with a dominant periodicity of 41,000 years to asymmetric high-amplitude cycles dominated by a periodicity of 100,000 years. However, a 2020 study concluded that ice age terminations might have been influenced by obliquity since the Mid-Pleistocene Transition, which caused stronger summers in the Northern Hemisphere . Glaciation in the Pleistocene
475-506: A copy of Principles and praising the book as opening a way for bold speculation on "that mystery of mysteries, the replacement of extinct species by others" – by analogy with other intermediate causes , "the origination of fresh species, could it ever come under our cognizance, would be found to be a natural in contradistinction to a miraculous process". Lyell replied: "In regard to the origination of new species, I am very glad to find that you think it probable that it may be carried on through
570-574: A deviation from today's annual mean temperature, taken as zero. This sort of graph is based on another isotope ratio versus time. Ratios are converted to a percentage difference from the ratio found in standard mean ocean water (SMOW). The graph in either form appears as a waveform with overtones . One half of a period is a Marine isotopic stage (MIS). It indicates a glacial (below zero) or an interglacial (above zero). Overtones are stadials or interstadials. According to this evidence, Earth experienced 102 MIS stages beginning at about 2.588 Ma BP in
665-421: A few regions had been studied and the names were relatively few. Today the geologists of different nations are taking more of an interest in Pleistocene glaciology. As a consequence, the number of names is expanding rapidly and will continue to expand. Many of the advances and stadials remain unnamed. Also, the terrestrial evidence for some of them has been erased or obscured by larger ones, but evidence remains from
760-590: A profession, entering Lincoln's Inn in 1820. He completed a circuit through rural England, where he could observe geological phenomena. In 1821 he attended Robert Jameson 's lectures in Edinburgh, and visited Gideon Mantell at Lewes , in Sussex . In 1823 he was elected joint secretary of the Geological Society . As his eyesight began to deteriorate, he turned to geology as a full-time profession. His first paper, "On
855-582: A profitable mining area, bears Lyell's name; and the Lyell Range in north-west Western Australia is named after him as well. In Southwest Nelson in the South Island of New Zealand, the Lyell Range, Lyell River and the gold mining town of Lyell (now only a camping site) were all named after Lyell. Lyall Bay in Wellington, New Zealand was possibly named after Lyell. The jawless fish Cephalaspis lyelli , from
950-513: A recent formation of freshwater limestone in Forfarshire", was presented in 1826. By 1827, he had abandoned law and embarked on a geological career that would result in fame and the general acceptance of uniformitarianism, a working out of the ideas proposed by James Hutton a few decades earlier. In 1832, Lyell married Mary Horner in Bonn, daughter of Leonard Horner (1785–1864), also associated with
1045-468: A remarkable series of nearly three hundred manuscript notebooks and diaries. These span Lyell's long scientific career (1825–1874), and offer an unrivalled insight into personal influences, field observations, thoughts and relationships. They were acquired in 2019 by the University of Edinburgh 's Heritage Collections, thanks to a fundraising campaign, with many generous individual and institutional donors from
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#17328479827871140-568: A team of Russian scientists in collaboration with Princeton University announced that they had brought two female nematodes frozen in permafrost , from around 42,000 years ago, back to life. The two nematodes, at the time, were the oldest confirmed living animals on the planet. The evolution of anatomically modern humans took place during the Pleistocene. At the beginning of the Pleistocene Paranthropus species were still present, as well as early human ancestors, but during
1235-491: A wide range of readers of the significance of " deep time " for understanding the earth and environment. Lyell's scientific contributions included a pioneering explanation of climate change, in which shifting boundaries between oceans and continents could be used to explain long-term variations in temperature and rainfall. Lyell also gave influential explanations of earthquakes and developed the theory of gradual "backed up-building" of volcanoes . In stratigraphy his division of
1330-756: Is as fatal to the theory of successive development, as if several hundreds had been discovered." In the first edition of Principles , the first volume briefly set out Lyell's concept of a steady state with no real progression of fossils. The sole exception was the advent of humanity, with no great physical distinction from animals, but with absolutely unique intellectual and moral qualities. The second volume dismissed Lamarck's claims of animal forms arising from habits, continuous spontaneous generation of new life, and man having evolved from lower forms. Lyell explicitly rejected Lamarck's concept of transmutation of species, drawing on Cuvier's arguments, and concluded that species had been created with stable attributes. He discussed
1425-493: Is best known, however, for his role in elaborating the doctrine of uniformitarianism . He played a critical role in advancing the study of loess . From 1830 to 1833 his multi-volume Principles of Geology was published. The work's subtitle was "An attempt to explain the former changes of the earth's surface by reference to causes now in operation", and this explains Lyell's impact on science. He drew his explanations from field studies conducted directly before he went to work on
1520-765: Is estimated that, at maximum glacial extent, 30% of the Earth's surface was covered by ice. In addition, a zone of permafrost stretched southward from the edge of the glacial sheet, a few hundred kilometres in North America , and several hundred in Eurasia . The mean annual temperature at the edge of the ice was −6 °C (21 °F); at the edge of the permafrost, 0 °C (32 °F). Each glacial advance tied up huge volumes of water in continental ice sheets 1,500 to 3,000 metres (4,900–9,800 ft) thick, resulting in temporary sea-level drops of 100 metres (300 ft) or more over
1615-454: Is no systematic correspondence between pluvials to glacials, however. Moreover, regional pluvials do not correspond to each other globally. For example, some have used the term "Riss pluvial" in Egyptian contexts. Any coincidence is an accident of regional factors. Only a few of the names for pluvials in restricted regions have been stratigraphically defined. The sum of transient factors acting at
1710-452: Is to happen thereafter." Geological remains from the distant past can, and should, be explained by reference to geological processes now in operation and thus directly observable. Lyell's interpretation of geological change as the steady accumulation of minute changes over enormously long spans of time was a powerful influence on the young Charles Darwin . Lyell asked Robert FitzRoy , captain of HMS Beagle , to search for erratic boulders on
1805-578: The Ice Age ) is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations . Before a change was finally confirmed in 2009 by the International Union of Geological Sciences , the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of
1900-638: The Alpine ice sheet on the Alps . Scattered domes stretched across Siberia and the Arctic shelf. The northern seas were ice-covered. South of the ice sheets large lakes accumulated because outlets were blocked and the cooler air slowed evaporation. When the Laurentide Ice Sheet retreated, north-central North America was completely covered by Lake Agassiz . Over a hundred basins, now dry or nearly so, were overflowing in
1995-594: The Anthropocene . Building on the innovative work of James Hutton and his follower John Playfair , Lyell favoured an indefinitely long age for the earth, despite evidence suggesting an old but finite age. He was a close friend of Charles Darwin , and contributed significantly to Darwin's thinking on the processes involved in evolution. As Darwin wrote in On the Origin of Species , "He who can read Sir Charles Lyell's grand work on
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#17328479827872090-627: The British Geological Survey (founded in 1835), and the US Geological Survey (founded in 1879), map and exhibit the natural resources within their countries. Over time, these surveys have been used extensively by modern extractive industries, such as nuclear, coal and oil. Before the work of Lyell, phenomena such as earthquakes were understood by the destruction that they brought. One of the contributions that Lyell made in Principles
2185-535: The Elements in 1838. The book went through six editions, eventually growing to two volumes and ceasing to be the inexpensive, portable handbook that Lyell had originally envisioned. Late in his career, therefore, Lyell produced a condensed version titled Student's Elements of Geology that fulfilled the original purpose. Geological Evidences of the Antiquity of Man brought together Lyell's views on three key themes from
2280-653: The Geological Society of London . The new couple spent their honeymoon in Switzerland and Italy on a geological tour of the area. During the 1840s, Lyell travelled to the United States and Canada, and wrote two popular travel-and-geology books: Travels in North America (1845) and A Second Visit to the United States (1849). In 1866, he was elected a foreign member of the Royal Swedish Academy of Sciences . After
2375-681: The Great Chicago Fire in 1871, Lyell was one of the first to donate books to help found the Chicago Public Library . In 1841, Lyell was elected as a member to the American Philosophical Society . Lyell's wife died in 1873, and two years later (in 1875) Lyell himself died as he was revising the twelfth edition of Principles . He is buried in Westminster Abbey where there is a bust to him by William Theed in
2470-673: The Highlands . His family's second country home was in a completely different geological and ecological area: he spent much of his childhood at Bartley Lodge in the New Forest , in Hampshire in southern England. Lyell entered Exeter College, Oxford , in 1816, and attended William Buckland 's geological lectures. He graduated with a BA Hons. second class degree in classics, in December 1819, and gained his M.A. 1821. After graduation he took up law as
2565-503: The Holocene by French paleontologist Paul Gervais in 1867 – included all deposits from the era subject to human observation. In recent years Lyell's subdivisions have been widely discussed in relation to debates about the Anthropocene . In Principles of Geology (first edition, vol. 3, ch. 2, 1833) Lyell proposed that icebergs could be the means of transport for erratics . During periods of global warming, ice breaks off
2660-521: The ICS timescale, the Pleistocene is divided into four stages or ages , the Gelasian , Calabrian , Chibanian (previously the unofficial "Middle Pleistocene"), and Upper Pleistocene (unofficially the "Tarantian"). In addition to these international subdivisions, various regional subdivisions are often used. In 2009 the International Union of Geological Sciences (IUGS) confirmed a change in time period for
2755-631: The Isthmus of Panama , causing a faunal interchange between the two regions and changing ocean circulation patterns, with the onset of glaciation in the Northern Hemisphere occurring around 2.7 million years ago. During the Early Pleistocene (2.58–0.8 Ma), archaic humans of the genus Homo originated in Africa and spread throughout Afro-Eurasia . The end of the Early Pleistocene is marked by
2850-660: The Laurentide Ice Sheet . Charles Lyell introduced the term "Pleistocene" in 1839 to describe strata in Sicily that had at least 70% of their molluscan fauna still living today. This distinguished it from the older Pliocene Epoch , which Lyell had originally thought to be the youngest fossil rock layer. He constructed the name "Pleistocene" ('most new' or 'newest') from the Greek πλεῖστος ( pleīstos ) 'most' and καινός ( kainós ( Latinized as cænus ) 'new'). This contrasts with
2945-593: The Mid-Pleistocene Transition , with the cyclicity of glacial cycles changing from 41,000-year cycles to asymmetric 100,000-year cycles, making the climate variation more extreme. The Late Pleistocene witnessed the spread of modern humans outside of Africa as well as the extinction of all other human species. Humans also spread to the Australian continent and the Americas for the first time, co-incident with
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3040-522: The Old Red Sandstone of southern Scotland, was named by Louis Agassiz in honour of Lyell. Sir Charles Lyell was buried at Westminster Abbey on 27 February 1875. The pallbearers included T. H. Huxley , the Rev. W. S. Symonds and Mr John Carrick Moore . Lyell had private means, and earned further income as an author. He came from a prosperous family, worked briefly as a lawyer in the 1820s, and held
3135-635: The Ruwenzori Range in east and central Africa were larger. Glaciers existed in the mountains of Ethiopia and to the west in the Atlas Mountains . In the northern hemisphere, many glaciers fused into one. The Cordilleran Ice Sheet covered the North American northwest; the east was covered by the Laurentide . The Fenno-Scandian ice sheet rested on northern Europe , including much of Great Britain;
3230-514: The Tertiary period into the Pliocene , Miocene , and Eocene was highly influential. He incorrectly conjectured that icebergs were the impetus behind the transport of glacial erratics , and that silty loess deposits might have settled out of flood waters. His creation of a separate period for human history, entitled the 'Recent', is widely cited as providing the foundations for the modern discussion of
3325-477: The last glacial period ended about 10,000 years ago. Over 11 major glacial events have been identified, as well as many minor glacial events. A major glacial event is a general glacial excursion, termed a "glacial." Glacials are separated by "interglacials". During a glacial, the glacier experiences minor advances and retreats. The minor excursion is a "stadial"; times between stadials are "interstadials". These events are defined differently in different regions of
3420-689: The survey voyage of the Beagle , and just before it set out FitzRoy gave Darwin Volume 1 of the first edition of Lyell's Principles . When the Beagle made its first stop ashore at St Jago in the Cape Verde islands, Darwin found rock formations which seen "through Lyell's eyes" gave him a revolutionary insight into the geological history of the island, an insight he applied throughout his travels. While in South America Darwin received Volume 2 which considered
3515-588: The woolly rhinoceros , various giraffids , such as the Sivatherium ; ground sloths , Irish elk , cave lions , cave bears , Gomphotheres , American lions , dire wolves , and short-faced bears , began late in the Pleistocene and continued into the Holocene. Neanderthals also became extinct during this period. At the end of the last ice age, cold-blooded animals, smaller mammals like wood mice , migratory birds, and swifter animals like whitetail deer had replaced
3610-558: The Early Pleistocene Gelasian . Early Pleistocene stages were shallow and frequent. The latest were the most intense and most widely spaced. By convention, stages are numbered from the Holocene, which is MIS1. Glacials receive an even number and interglacials receive an odd number. The first major glacial was MIS2-4 at about 85–11 ka BP. The largest glacials were 2, 6, 12, and 16. The warmest interglacials were 1, 5, 9 and 11. For matching of MIS numbers to named stages, see under
3705-409: The Earth's surface is cyclical: climate, ocean currents and other movements, wind currents, temperature, etc. The waveform response comes from the underlying cyclical motions of the planet, which eventually drag all the transients into harmony with them. The repeated glaciations of the Pleistocene were caused by the same factors. The Mid-Pleistocene Transition , approximately one million years ago, saw
3800-479: The North American west. Lake Bonneville , for example, stood where Great Salt Lake now does. In Eurasia, large lakes developed as a result of the runoff from the glaciers. Rivers were larger, had a more copious flow, and were braided . African lakes were fuller, apparently from decreased evaporation. Deserts, on the other hand, were drier and more extensive. Rainfall was lower because of the decreases in oceanic and other evaporation. It has been estimated that during
3895-450: The Origin of Species , Lyell finally offered a tepid endorsement of evolution in the tenth edition of Principles . Elements of Geology began as the fourth volume of the third edition of Principles : Lyell intended the book to act as a suitable field guide for students of geology. The systematic, factual description of geological formations of different ages contained in Principles grew so unwieldy, however, that Lyell split it off as
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3990-434: The Pleistocene to 2.58 Ma, results in the inclusion of all the recent repeated glaciations within the Pleistocene. Radiocarbon dating is considered to be inaccurate beyond around 50,000 years ago. Marine isotope stages (MIS) derived from Oxygen isotopes are often used for giving approximate dates. Pleistocene non-marine sediments are found primarily in fluvial deposits , lakebeds, slope and loess deposits as well as in
4085-490: The Pleistocene's overall climate could be characterised as a continuous El Niño with trade winds in the south Pacific weakening or heading east, warm air rising near Peru , warm water spreading from the west Pacific and the Indian Ocean to the east Pacific, and other El Niño markers. Pleistocene climate was marked by repeated glacial cycles in which continental glaciers pushed to the 40th parallel in some places. It
4180-494: The Pleistocene, changing the start date from 1.806 to 2.588 million years BP, and accepted the base of the Gelasian as the base of the Pleistocene, namely the base of the Monte San Nicola GSSP . The start date has now been rounded down to 2.580 million years BP. The IUGS has yet to approve a type section , Global Boundary Stratotype Section and Point (GSSP), for the upper Pleistocene/Holocene boundary ( i.e.
4275-782: The Pleistocene, the East Antarctic Ice Sheet thinned by at least 500 meters, and that thinning since the Last Glacial Maximum is less than 50 meters and probably started after ca 14 ka. During the 2.5 million years of the Pleistocene, numerous cold phases called glacials ( Quaternary ice age ), or significant advances of continental ice sheets, in Europe and North America, occurred at intervals of approximately 40,000 to 100,000 years. The long glacial periods were separated by more temperate and shorter interglacials which lasted about 10,000–15,000 years. The last cold episode of
4370-411: The Pleistocene, the plates upon which they sit probably having moved no more than 100 km (62 mi) relative to each other since the beginning of the period. In glacial periods, the sea level would drop by up to 120 m (390 ft) lower than today during peak glaciation, exposing large areas of the present continental shelf as dry land. According to Mark Lynas (through collected data),
4465-464: The Principles of Geology, which the future historian will recognise as having produced a revolution in natural science, yet does not admit how incomprehensibly vast have been the past periods of time, may at once close this volume." Lyell helped to arrange the simultaneous publication in 1858 of papers by Darwin and Alfred Russel Wallace on natural selection , despite his personal religious qualms about
4560-569: The UK and overseas. Highlights include his travels throughout Europe and the United States of America, the drafts of his correspondence with the likes of Charles Darwin, his geological and landscape sketches and his constant gathering of evidence and refinement of his theories. Principles of Geology , Lyell's first book, was also his most famous, most influential, and most important. First published in three volumes in 1830–33, it established Lyell's credentials as an important geological theorist and propounded
4655-524: The ancient spirit of speculation revived, and a desire manifestly shown to cut, rather than patiently untie, the Gordian Knot. -Sir Charles Lyell, Principles of Geology , 1854 edition, p. 196; quoted by Stephen Jay Gould . Lyell saw himself as "the spiritual saviour of geology, freeing the science from the old dispensation of Moses." The two terms, uniformitarianism and catastrophism , were both coined by William Whewell ; in 1866 R. Grove suggested
4750-687: The appearance of Homo sapiens about 300,000 years ago. Artifacts associated with modern human behavior are unambiguously attested starting 40,000–50,000 years ago. According to mitochondrial timing techniques, modern humans migrated from Africa after the Riss glaciation in the Middle Palaeolithic during the Eemian Stage , spreading all over the ice-free world during the late Pleistocene. A 2005 study posits that humans in this migration interbred with archaic human forms already outside of Africa by
4845-515: The articles for those names. Both marine and continental faunas were essentially modern but with many more large land mammals such as Mammoths , Mastodons , Diprotodons , Smilodons , tigers , lions , Aurochs , short-faced bears , giant sloths , species within Gigantopithecus and others. Isolated landmasses such as Australia , Madagascar , New Zealand and islands in the Pacific saw
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#17328479827874940-495: 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
5035-586: The doctrine of uniformitarianism . It was a work of synthesis, backed by his own personal observations on his travels. The central argument in Principles was that the present is the key to the past – a concept of the Scottish Enlightenment which David Hume had stated as "all inferences from experience suppose ... that the future will resemble the past", and James Hutton had described when he wrote in 1788 that "from what has actually been, we have data for concluding with regard to that which
5130-606: The entire surface of the Earth. During interglacial times, such as at present, drowned coastlines were common, mitigated by isostatic or other emergent motion of some regions. The effects of glaciation were global. Antarctica was ice-bound throughout the Pleistocene as well as the preceding Pliocene. The Andes were covered in the south by the Patagonian ice cap. There were glaciers in New Zealand and Tasmania . The current decaying glaciers of Mount Kenya , Mount Kilimanjaro , and
5225-772: The evolution of large birds and even reptiles such as the Elephant bird , moa , Haast's eagle , Quinkana , Megalania and Meiolania . The severe climatic changes during the Ice Age had major impacts on the fauna and flora. With each advance of the ice, large areas of the continents became depopulated, and plants and animals retreating southwards in front of the advancing glacier faced tremendous stress. The most severe stress resulted from drastic climatic changes, reduced living space, and curtailed food supply. A major extinction event of large mammals ( megafauna ), which included mammoths , mastodons , saber-toothed cats , glyptodons ,
5320-444: The extinction of most large-bodied animals in these regions. The aridification and cooling trends of the preceding Neogene were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, with the sea levels being up to 120 metres (390 ft) lower than present at peak glaciation, allowing the connection of Asia and North America via Beringia and the covering of most of northern North America by
5415-422: The formation of atolls , which supported Lyell's uniformitarianism. On the return of the Beagle (October 1836) Lyell invited Darwin to dinner and from then on they were close friends. Although Darwin discussed evolutionary ideas with him from 1842, Lyell continued to reject evolution in each of the first nine editions of the Principles . He encouraged Darwin to publish, and following the 1859 publication of On
5510-583: The fossil record indicated a directional geohistory in which species went extinct. Around 1826, when he was on circuit, he read Lamarck 's Zoological Philosophy and on 2 March 1827 wrote to Mantell , expressing admiration, but cautioning that he read it "rather as I hear an advocate on the wrong side, to know what can be made of the case in good hands".: He struggled with the implications for human dignity, and later in 1827 wrote private notes on Lamarck's ideas. Lyell reconciled transmutation of species with natural theology by suggesting that it would be as much
5605-598: The founding geology text. He was, along with the earlier John Playfair , the major advocate of James Hutton 's idea of uniformitarianism , that the earth was shaped entirely by slow-moving forces still in operation today, acting over a very long period of time. This was in contrast to catastrophism , an idea of abrupt geological changes, which had been adapted in England to explain landscape features—such as rivers much smaller than their associated valleys—that seemed impossible to explain other than through violent action. Criticizing
5700-588: The geographical distribution of plants and animals, and proposed that every species of plant or animal was descended from a pair or individual, originated in response to differing external conditions. Species would regularly go extinct, in a "struggle for existence" between hybrids, or a "war one with another" due to population pressure. He was vague about how replacement species formed, portraying this as an infrequent occurrence which could rarely be observed. The leading man of science Sir John Herschel wrote from Cape Town on 20 February 1836, thanking Lyell for sending
5795-785: The geology of the Quaternary Period of earth history: glaciers, evolution, and the age of the human race . First published in 1863, it went through three editions that year, with a fourth and final edition appearing in 1873. The book was widely regarded as a disappointment because of Lyell's equivocal treatment of evolution . Lyell, a highly religious man with a strong belief in the special status of human reason, had great difficulty reconciling his beliefs with natural selection . Lyell's geological interests ranged from volcanoes and geological dynamics through stratigraphy , palaeontology , and glaciology to topics that would now be classified as prehistoric archaeology and paleoanthropology . He
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#17328479827875890-414: The glacial range, which have their own glacial history depending on latitude, terrain and climate. There is a general correspondence between glacials in different regions. Investigators often interchange the names if the glacial geology of a region is in the process of being defined. However, it is generally incorrect to apply the name of a glacial in one region to another. For most of the 20th century, only
5985-450: The historical terminology was established. Corresponding to the terms glacial and interglacial, the terms pluvial and interpluvial are in use (Latin: pluvia , rain). A pluvial is a warmer period of increased rainfall; an interpluvial is of decreased rainfall. Formerly a pluvial was thought to correspond to a glacial in regions not iced, and in some cases it does. Rainfall is cyclical also. Pluvials and interpluvials are widespread. There
6080-430: The ideas of Jean-Baptiste Lamarck in some detail. Lyell rejected Lamarck's idea of organic evolution , proposing instead "Centres of Creation" to explain diversity and territory of species. However, as discussed below , many of his letters show he was fairly open to the idea of evolution. In geology Darwin was very much Lyell's disciple, and brought back observations and his own original theorising, including ideas about
6175-445: The immediately preceding Pliocene ("newer", from πλείων ( pleíōn , "more") and kainós ) and the immediately subsequent Holocene ("wholly new" or "entirely new", from ὅλος ( hólos , "whole") and kainós ) epoch , which extends to the present time. The Pleistocene has been dated from 2.580 million (±0.005) to 11,700 years BP with the end date expressed in radiocarbon years as 10,000 carbon-14 years BP. It covers most of
6270-449: The intervention of intermediate causes. I left this rather to be inferred, not thinking it worth while to offend a certain class of persons by embodying in words what would only be a speculation." Whewell subsequently questioned this topic, and in March 1837 Lyell told him: As a result of his letters and, no doubt, personal conversations, Huxley and Ernst Haeckel were convinced that, at
6365-613: The large amounts of material moved about by glaciers. Less common are cave deposits, travertines and volcanic deposits (lavas, ashes). Pleistocene marine deposits are found primarily in shallow marine basins mostly (but with important exceptions) in areas within a few tens of kilometres of the modern shoreline. In a few geologically active areas such as the Southern California coast, Pleistocene marine deposits may be found at elevations of several hundred metres. The modern continents were essentially at their present positions during
6460-409: The late Pleistocene, incorporating archaic human genetic material into the modern human gene pool. Charles Lyell Sir Charles Lyell, 1st Baronet , FRS (14 November 1797 – 22 February 1875) 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
6555-526: The latest period of repeated glaciation , up to and including the Younger Dryas cold spell. The end of the Younger Dryas has been dated to about 9700 BCE (11,700 calendar years BP). The end of the Younger Dryas is the official start of the current Holocene Epoch . Although it is considered an epoch, the Holocene is not significantly different from previous interglacial intervals within the Pleistocene. In
6650-420: The lower Palaeolithic they disappeared, and the only hominin species found in fossilic records is Homo erectus for much of the Pleistocene. Acheulean lithics appear along with Homo erectus , some 1.8 million years ago, replacing the more primitive Oldowan industry used by A. garhi and by the earliest species of Homo . The Middle Paleolithic saw more varied speciation within Homo , including
6745-478: The megafauna and migrated north. Late Pleistocene bighorn sheep were more slender and had longer legs than their descendants today. Scientists believe that the change in predator fauna after the late Pleistocene extinctions resulted in a change of body shape as the species adapted for increased power rather than speed. The extinctions hardly affected Africa but were especially severe in North America where native horses and camels were wiped out. In July 2018,
6840-478: The most explosive volcanoes on Earth during the Pleistocene along with Yellowstone Caldera and Lake Toba . It is the only known supervolcano located directly on a mid-ocean ridge . This article about a specific oceanic location or ocean current is a stub . You can help Misplaced Pages by expanding it . Pleistocene The Pleistocene ( / ˈ p l aɪ s t ə ˌ s iː n , - s t oʊ -/ PLY -stə-seen, -stoh- ; referred to colloquially as
6935-756: The north aisle. Lyell was knighted ( Kt ) in 1848, and later, in 1864, made a baronet ( Bt ), which is an hereditary honour. He was awarded the Copley Medal of the Royal Society in 1858 and the Wollaston Medal of the Geological Society in 1866. Mount Lyell , the highest peak in Yosemite National Park , is named after him; the crater Lyell on the Moon and a crater on Mars were named in his honour; Mount Lyell in western Tasmania, Australia, located in
7030-567: The number and proportion of marine shells encased within. Based on this the third volume of his Principles of Geology , published in 1833, proposed dividing the Tertiary period into four parts, which he named the Eocene , Miocene , Pliocene , and Recent. In 1839, Lyell termed the Pleistocene epoch, distinguishing a more recent fossil layer from the Pliocene. The Recent epoch – renamed
7125-472: The period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology . The name is a combination of Ancient Greek πλεῖστος ( pleîstos ) 'most' and καινός ( kainós ; Latinized as cænus ) 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by
7220-408: The poles and floats across submerged continents, carrying debris with it, he conjectured. When the iceberg melts, it rains down sediments upon the land. Because this theory could account for the presence of diluvium, the word drift became the preferred term for the loose, unsorted material, today called till . Furthermore, Lyell believed that the accumulation of fine angular particles covering much of
7315-552: The post of Professor of Geology at King's College London in the 1830s. From 1830 onward his books provided both income and fame. Each of his three major books was a work continually in progress. All three went through multiple editions during his lifetime, although many of his friends (such as Darwin) thought the first edition of the Principles was the best written. Lyell used each edition to incorporate additional material, rearrange existing material, and revisit old conclusions in light of new evidence. Throughout his life, Lyell kept
7410-417: The ratio of O to O (two isotopes of oxygen ) by mass (measured by a mass spectrometer ) present in the calcite of oceanic core samples is used as a diagnostic of ancient ocean temperature change and therefore of climate change. Cold oceans are richer in O , which is included in the tests of the microorganisms ( foraminifera ) contributing the calcite. A more recent version of
7505-455: The recent period of repeated glaciations. The name Plio-Pleistocene has, in the past, been used to mean the last ice age. Formerly, the boundary between the two epochs was drawn at the time when the foraminiferal species Hyalinea baltica first appeared in the marine section at La Castella, Calabria, Italy. However, the revised definition of the Quaternary , by pushing back the start date of
7600-453: The reliance of his contemporaries on what he argued were ad hoc explanations, Lyell wrote, Never was there a doctrine more calculated to foster indolence, and to blunt the keen edge of curiosity, than this assumption of the discordance between the former and the existing causes of change... The student was taught to despond from the first. Geology, it was affirmed, could never arise to the rank of an exact science... [With catastrophism] we see
7695-407: The sampling process makes use of modern glacial ice cores. Although less rich in O than seawater, the snow that fell on the glacier year by year nevertheless contained O and O in a ratio that depended on the mean annual temperature. Temperature and climate change are cyclical when plotted on a graph of temperature versus time. Temperature coordinates are given in the form of
7790-443: The simpler term continuity for Lyell's view, but the old terms persisted. In various revised editions (12 in all, through 1872), Principles of Geology was the most influential geological work in the middle of the 19th century, and did much to put geology on a modern footing. Lyell noted the "economic advantages" that geological surveys could provide, citing their felicity in mineral-rich countries and provinces. Modern surveys, like
7885-632: The sole factor responsible for the variations in climate since they explain neither the long-term cooling trend over the Plio-Pleistocene nor the millennial variations in the Greenland Ice Cores known as Dansgaard-Oeschger events and Heinrich events. Milankovitch pacing seems to best explain glaciation events with periodicity of 100,000, 40,000, and 20,000 years. Such a pattern seems to fit the information on climate change found in oxygen isotope cores. In oxygen isotope ratio analysis, variations in
7980-421: The study of cyclical climate changes. The glacials in the following tables show historical usages, are a simplification of a much more complex cycle of variation in climate and terrain, and are generally no longer used. These names have been abandoned in favour of numeric data because many of the correlations were found to be either inexact or incorrect and more than four major glacials have been recognised since
8075-643: The study of nature. Lyell's grandfather, also Charles Lyell, had made the family fortune supplying the Royal Navy at Montrose , enabling him to buy Kinnordy House. The family seat is located in Strathmore , near the Highland Boundary Fault . Round the house, in the strath , is good farmland, but within a short distance to the north-west, on the other side of the fault, are the Grampian Mountains in
8170-658: The theory of natural selection by Darwin and Alfred Russel Wallace in 1858: each had arrived at the theory independently. Lyell's views on gradual change and the power of a long time scale were important because Darwin thought that populations of an organism changed very slowly. Although Lyell rejected evolution at the time of writing the Principles , after the Darwin–Wallace papers and the Origin Lyell wrote in one of his notebooks on 3 May 1860: Lyell's acceptance of natural selection, Darwin's proposed mechanism for evolution,
8265-433: The theory. He later published evidence from geology of the time man had existed on the earth. Lyell was born into a wealthy family, on 14 November 1797, at the family's estate house , Kinnordy House , near Kirriemuir in Forfarshire. He was the eldest of ten children. Lyell's father, also named Charles Lyell , was noted as a translator and scholar of Dante . An accomplished botanist, it was he who first exposed his son to
8360-521: The time he wrote Principles , he believed new species had arisen by natural methods. Adam Sedgwick wrote worried letters to him about this. By the time Darwin returned from the Beagle survey expedition in 1836, he had begun to doubt Lyell's ideas about the permanence of species. He continued to be a close personal friend, and Lyell was one of the first scientists to support On the Origin of Species , though he did not subscribe to all its contents. Lyell
8455-446: The upheaval argument supported by other geologists. Lyell was a key figure in establishing the classification of more recent geological deposits, long known as the Tertiary period. From May 1828, until February 1829, he travelled with Roderick Impey Murchison (1792–1871) to the south of France (Auvergne volcanic district) and to Italy. In these areas he concluded that the recent strata (rock layers) could be categorised according to
8550-622: The upper boundary). The proposed section is the North Greenland Ice Core Project ice core 75° 06' N 42° 18' W. The lower boundary of the Pleistocene Series is formally defined magnetostratigraphically as the base of the Matuyama (C2r) chronozone , isotopic stage 103. Above this point there are notable extinctions of the calcareous nannofossils : Discoaster pentaradiatus and Discoaster surculus . The Pleistocene covers
8645-401: The world (today called loess ) was a deposit settled from mountain flood water. Today some of Lyell's mechanisms for geological processes have been disproven, though many have stood the test of time. His observational methods and general analytical framework remain in use today as foundational principles in geology. Lyell initially accepted the conventional view of other men of science, that
8740-543: Was a series of glacials and interglacials, stadials and interstadials, mirroring periodic climate changes. The main factor at work in climate cycling is now believed to be Milankovitch cycles . These are periodic variations in regional and planetary solar radiation reaching the Earth caused by several repeating changes in the Earth's motion. The effects of Milankovitch cycles were enhanced by various positive feedbacks related to increases in atmospheric carbon dioxide concentrations and Earth's albedo. Milankovitch cycles cannot be
8835-399: Was also a friend of Darwin's closest colleagues, Joseph Dalton Hooker and Huxley , but unlike them he struggled to square his religious beliefs with evolution. This inner struggle has been much commented on. He had particular difficulty in believing in natural selection as the main motive force in evolution. Lyell and Hooker were instrumental in arranging the peaceful co-publication of
8930-571: Was equivocal, and came in the tenth edition of Principles . The Antiquity of Man (published in early February 1863, just before Huxley's Man's place in nature ) drew these comments from Darwin to Huxley: "I am fearfully disappointed at Lyell's excessive caution" and "The book is a mere 'digest'". Quite strong remarks: no doubt Darwin resented Lyell's repeated suggestion that he owed a lot to Lamarck , whom he (Darwin) had always specifically rejected. Darwin's daughter Henrietta (Etty) wrote to her father: "Is it fair that Lyell always calls your theory
9025-421: Was to explain the cause of earthquakes. Lyell, in contrast focused on recent earthquakes (150 yrs), evidenced by surface irregularities such as faults, fissures, stratigraphic displacements and depressions. Lyell's work on volcanoes focused largely on Vesuvius and Etna , both of which he had earlier studied. His conclusions supported gradual building of volcanoes, so-called "backed up-building", as opposed to
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