Darwin the Geologist


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Charles Darwin and the geology of the Galapagos Islands. Created by Dave Lageson.

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Darwin the Geologist

  1. 1. Charles Robert Darwin (1809-1882):The making of a Geologist
  2. 2. “I a geologist have illdefined notion of landcovered with ocean, former animals, slow forcecracking surface &c truly poetical.”
  3. 3. Born to do Science• Born February 12, 1809 in Shrewsbury, England(west-Wales)• Mother (Susannah) was a Wedgewood (pottery);died when Darwin was only 8 years old• Father (Robert Waring Darwin) was an esteemedmedical doctor and Fellow of the Royal Society• Grandfathers on both sides were intellectuals:– Erasmus Darwin  physician, inventor, poet andnatural philosopher– Josiah Wedgewood  potter, inventor, patron ofthe arts, and prominent slavery abolitionist
  4. 4. Shrewsbury Public Library, CastlegatesShrewsbury town square
  5. 5. Shrewsbury Town Square & Market1850
  6. 6. Shrewsbury PublicLibrary, Castlegates; formerlyhoused Charles Darwins almamaterDarwin attended school herefrom 1818-1825Charles as a child, with his sisterCatherine (Cambridgeshire Collection)
  7. 7. Erasmus Darwin (1731-1802)• English physician• One of the key thinkers ofthe Enlightenment, he wasalso a naturalphilosopher, physiologist, slave tradeabolitionist,inventor andpoet• His poems included muchnatural history, including astatement of evolution and…the relatedness of allforms of life
  8. 8. Erasmus DarwinCharles Darwin’spaternal grandfather
  9. 9. Josiah Wedgewood (1730-1795
  10. 10. Typical blueWedgewoodplate
  11. 11. England’s Industrial Revolution• Early years of the industrial revolution (coal-powered)• Scientific thought and innovative ideas were encouraged• Early ideas about evolution had germinated during the 18th centuryand became more cohesive in early 19th century– French naturalist Compte de Buffon  father of natural historythought during the second half of the 18th century– French naturalist Jean-Baptiste Pierre Antoine de Monet, Chevalierde Lamark  Philosophie Zoologique in which evolution was presentedas a theory (characteristics acquired by an individual during its lifetimeare passed down to its offspring)– Erasmus Darwin  suggested that every living thing had “degeneratedfrom a single living filament”– Many others…Jean-Baptiste Lamarck
  12. 12. Jean-Baptiste Lamarck
  13. 13. The Education of Charles Darwin• Early youth  gardening, fishing, rockcollecting, examining flowers, taking longsolitary walks, climbing trees, generalcollector• Shrewsbury School  labeled a “trifler”• University of Edinburgh (1825-27) studied medicine as the insistence of hisfather; quit after two years, but he wasnevertheless baptized into contemporaryscientific thinking– Studiedmeteorology, mineralogy, geology, botany,zoology, anatomy, etc.– Exposed to the ideas of Cuvier, AbrahamGottlob Werner & James Hutton
  14. 14. Georges Léopold Chrétien FrédéricDagobert Cuvier (1769-1832)• French Baron, naturalist, zoologist• Brilliant comparative anatomist and paleontologist• Had a major impact on Charles Darwin when hestudied medicine at the University of Edinburgh• Cuvier’s Important scientific contributions: Established the fact of extinction Fine-tuned the Linnaeus classification bycomparing the internal structure of organisms Rigorously compared the anatomy of livingorganisms with fossils Showed that species become more complex anddiverse as they are replaced through time
  15. 15. Abraham Gottlob Werner (1749-1817)• German geologist who developed anearly theory about the stratification ofthe Earths crust• Led the school of thought called“Neptunism”• Though much of Werners theoreticalwork was erroneous, science isindebted to him for clearlydemonstrating the chronologicalsuccession of rocks• Zealous teacher who greatly inspiredhis students• Has been called the “father of Germangeology”
  16. 16. Cambridge University• Attended from 1828- 1831• A great time for Darwin“I clambered over the mountains…with a bounding step andmade the volcanic rocks resound under my geological hammer!All this shows how ambitious I was.”• Mentored by mineralogy & botany Professor John StevensHenslow– Attended weekend meetings at Henslow’s house andwent on many field excursions– Became known as “the man who walks with Henslow”• Henslow taught Darwin how to pay attention to variation• Henslow also encourged Darwin to read the books ofAlexander Von Humboldt and John F.W. Herschel (APreliminary Discourse on the Study of Natural Philosophy) –these books had a huge influence on Darwin’s scientificdevelopment• Henslow also encouraged Darwin to study more geology:– Geology was growing fast at this time– Geology offered opportunities for “large views” of thenatural world– Henslow introduced Darwin to geology professor AdamSedgwickDarwin’s residence at Christ’s College, Cambridge
  17. 17. Christ’s College, Cambridge
  18. 18. Darwin’s geologicmentors during hisCambridge yearsSedgwickHenslowLyell Hooker
  19. 19. Adam Sedgwick(1785-1873)• One of the founders of moderngeology• Educated at TrinityCollege, Cambridge – studiedmathematics and theology• Proposed the Devonian andCambrian Periods• Guided the young Darwin in hispre-Beagle geological education• Held Woodwardian Professor ofGeology Chair at Cambridge from1818 until his death in 1873
  20. 20. Adam Sedgwick (1785-1873)• He founded the system for the classification ofCambrian rocks and, with RoderickMurchison, worked out the order of theCarboniferous and underlying Devonian strata(1830s)• Was the first to distinguish clearly betweenstratification, jointing, and slaty cleavage• He strongly believed that species of organismsoriginated in a succession of Divine creative actsthroughout the long expanse of history• While he became increasingly Evangelical withage, he strongly supported advances in geologyagainst conservative churchmen• However, Sedgwick never accepted the case forevolution made in On the Origin of Species in1859Sedgwick: 1887
  21. 21. Adam Sedgwick (1785-1873)• Worked with Sedgwick in August, 1831 in Wales• Sedgwick taught Darwin an array of field skills and detailed note takingthat proved invaluable on the voyage of the Beagle• Darwin learned the field skills and science of structural and stratigraphicgeology from the best• Darwin learned from Sedgwick the process of constructing a scientificargument from empirical facts• Darwin “came of age” as a scientist under Sedgwick’s mentorship• The two kept up a correspondence while Darwin was on the Beagleexpedition, and afterwards
  22. 22. The Cambrian (540-488 Ma)• Named in the 1830s bySedgwick after Cambria, theLatin names for Wales• Geologically complex area• Type section in northernWales  poorly fossiliferousdark siltstones andsandstones
  23. 23. Cambrian rocks, North WalesPoorly fossiliferous dark siltstones and sandstones
  24. 24. Founders of Deep Geologic TimeNicholas Steno (1660s)– Superposition– Original horizontalityCharles Lyell (1830s)– Cross-cutting relations– Principle of inclusion (xenoliths)William Smith (~1800)– Faunal succession– Fossil correlationJames Hutton (1785) = uniformitarianism
  25. 25. W. W. NortonSuperposition & Original HorizontalityNicholas Steno (Niels Stensen)Danish physician who settled in ItalyBecame physician to the Grand Duke of Tuscany
  26. 26. Charles LyellCharles Lyell, 1840
  27. 27. Cross-cutting relations & inclusionsCharles Lyell
  28. 28. Frontispiece to Elements of Geology
  29. 29. a) Sedimentary layers can beidentified by their ownunique assemblage offossilsb) Fossil organisms succeedone another in a definiteand determinable order(“biostratigraphy”)c) Stratigraphy can becorrelated based on theirfossil assemblagesWilliam “Strata” Smith
  30. 30. Canals of England
  31. 31. One of Smith’s sketches of dipping stratigraphy:
  32. 32. James Hutton (1726 – 1797)Lived during the Age of Enlightenment in Europe (Philosopherslike Voltaire, Kant, Hume and others encouraged people to cast asideconstraints of dogma and think for themselves)Discovery of physical laws by Newton and others made peoplelook to natural, not supernatural, processes to explain theuniverseConsidered the “Father” of modern geologyGentleman farmer in ScotlandTrained as a physician, but never practiced medicineMain interests in life = natural history (geology)
  33. 33. Hutton’s Great Contribution to Science-Uniformitarianism: Physical processes we observe today also operatedin the past and were responsible for the formation ofgeological features we see in outcrops Geologic change occurs over long periods of time Implication  the earth is ancient  very, very old
  34. 34. Hutton’s Famous Quotes: “The present is the key to the past” “We find no vestige of a beginning, noprospect of an end”Thus, Hutton conceived of the concept of DEEP TIME
  35. 35. Famous angular unconformity at Siccar Point, Scotland-- James Hutton --
  36. 36. W. W. NortonAngular Unconformity Nonconformity
  37. 37. W. W. NortonDisconformity
  38. 38. W. W. Norton
  39. 39. Voyage of the HMS Beagle27 December 1831 to 2 October 1836
  40. 40. Voyage of the HMS Beagle• It took three years and nine months for Beagle to reach Galápagos; during that time, Darwin became anexperienced field man & theorizer• He rode over 5000 km across the Pampas of Argentina and the Andes on horseback• Filled 18 field notebooks, four volumes of zoological observations, 13 volumes of geologicalobservations, composed several essays, kept a descriptive specimen catalogue, and maintained a diaryfrom beginning to end• Darwin’s top priority during the voyage was GEOLOGY; he wrote four times more geology notes (1,383pages) than zoology notes (368 pages) and collected 2,000 rock samples• He wrote five books with multiple volumes and editions based on his experiences on the voyage:1. Journal of Researches2. The structure and Distribution of Coral Reefs3. Geological Observations on the Volcanic Islnads visited during the Voyage of HMS Beagle4. Geological Observations on South America5. The Zoology of the Voyage of HMS Beagle (in five parts)
  41. 41. Coquimbo to Copiapò
  42. 42. Darwin’s Geological Research on theVoyage of the HMS Beagle• Foxes of the FalklandIslands• Giant fossil Pleistocenemammals• Active volcaniceruptions• Earthquakes• Tectonic uplift• Cross-sections acrossthe Andes
  43. 43. Discovery of Giant Fossil Mammals• Sept. 22, 1832 near BahíaBlanca, Argentina (10 months into thevoyage)• Several extinct species of Pleistocenemammals• He found a Megatherium that was morecomplete than the one described byCuvier, which he used to introduce theprinciple of extinction in the fossil record• Extinct mammals and their resemblanceto living species living in the same area ledDarwin to question the doctrine of “fixityof species”• Megatherium went extinct around 10,500years ago
  44. 44. Bahía Blanca
  45. 45. Bahía BlancaMegatherium
  46. 46. Megatherium• Megatherium was one of the largest land mammalsknown, weighing up to 4 tonnes and up to 6 m (20 ft) inlength from head to tail. It is the largest known groundsloth, as big as modern elephants and would have onlybeen exceeded in its time by a few species of mammoth.Although it was primarily a quadruped, its footprintsshow that it was capable of assuming a bipedal stance.This sloth, like a modern anteater, walked on the sides ofits feet because its claws prevented it from putting themflat on the ground. Megatherium species were membersof the abundant Pleistocene megafauna, large mammalsthat lived during the Pleistocene epoch.• Megatherium had a robust skeleton with a large pelvicgirdle and a broad muscular tail. Its large size enabled itto feed at heights unreachable by other contemporaryherbivores. Rising on its powerful hind legs and using itstail to form a tripod, Megatherium could support itsmassive body weight while using the curved claws on itslong forelegs to pull down branches with the choicestleaves. Its jaw is believed to have housed a longtongue, which it would then use to pull leaves into itsmouth, similar to the modern tree sloth.
  47. 47. American MegatheriumThe first M. americanumskeleton discovered in 1798
  48. 48. ActiveconvergentmarginPassivemarginPassivemarginNazcaPlateAtlanticPlate
  49. 49. Isochron map of the Nazca Plate South AmericaSyn-convergent extension in the Cordillera Blanca, PeruCredit: MicahJessup, Univ.Tenn.
  50. 50. ~2-15o SouthPeruFlat SlabSubductionsegments~27-33o SouthChile & Argentina SierrasPampeanasMendoza
  51. 51. 30o
  52. 52. Falkland Islands• Beagle arrived at East Falkland Island in March, 1833• Darwin found Paleozoic shells and corals  evidence oftectonic uplift• Darwin discovered a wide “stream of stones” that wasremarkable for their enormous size– Freeze-thaw processes, not earthquake shaking as Darwin believed– Left an impression that the landscape could change through violentmovements of the Earth’s crust• Darwin studied the famously fearless now-extinct (in 1876)Falkland Island wolf (Dusicyon australis)
  53. 53. West FalklandEast Falkland
  54. 54. Stone run at Mount Kent, East Falkland
  55. 55. Falkland Island Wolf (Fox)• Dusicyon australis• This was Darwin’s onlyexample outside Galapagosof an organism that exists asdistinct varieties onseparate islands• This discovery really shapedhis thinking on therelationship of geographyand the distribution oforganisms
  56. 56. Dusicyon australis
  57. 57. Dusicyon australis - Falkland Islands
  58. 58. Andean OrogenSouth American Cordillera
  59. 59. Darwin in the Andes• Darwin saw the Andes as the “backbone” ofthe South American continent• As such, it was a “great barrier” dividingeastern and western species• He kept lists of “birds and animals” seen onhis numerous transects of the Andes
  60. 60. Active Tectonics• January 1835  witnessed the sky-illuminating eruptionChile’s Osorno Volcano 100 km to the north• February 20, 1835  experienced a severe earthquake inValdiva– 70 villages destroyed– Large tsunami had deposited slabs of marine sediments high on thebeach– Fissures split the ground in all directions– The offshore island of Santa Maria was uplifted 9 ft.• Darwin came to understand that the geography of a place,and therefore its organisms, could change suddenly orgradually over time
  61. 61. Osorno Volcano - Chile• 2,652-metre (8,701 ft) high stratovolcano;resembles Mount Fuji in Japan• Osorno is one of the most activevolcanoes of the southern Chilean Andes,with 11 historical eruptions recordedbetween 1575 and 1869• The upper slopes of the volcano arealmost entirely covered in glaciers despiteits very modest altitude and latitude,sustained by the substantial snowfall inthe very moist maritime climate of theregion• Osorno sits on top of a 250,000-year-olderoded stratovolcano, La Picada, with a 6-km-wide caldera
  62. 62. Portillo Pass: Chilean/ArgentineBorder near Aconcagua• March 21, 1835  elevation 3,700m (12,140 ft.)• Discovered marine fossil shells on the “highest ridge”• Two weeks later he crossed the Uspallata Range and found asilicified coastal forest at over 2000m elevation• Time and time again he found evidence for tectonic upliftover long periods of geologic time, but sometimes occurringsuddenly
  63. 63. Los Penitentes – border of Chile & Argentina
  64. 64. Portillo Pass
  65. 65. Darwin’s HutNear Chilean-Argentine BorderWest of Mendoza (Los Penitentes)(April 2006)
  66. 66. Cerro Aconcagua
  67. 67. South face of Cerro AconcaguaHighest Peak in the Americas (6,962 metres; 22,841 ft)North of Mendoza (April 2006)
  68. 68. North side of Cerro Aconcagua
  69. 69. Puente del Inca Hot Springs
  70. 70. Darwin’s hand-drawn and hand-coloredcross-section of the Andes(from his voyage on the HMS Beagle)www.lib.cam.ac.uk/exhibitions/Darwin/theory.html
  71. 71. Ideal (and highly simplified) model of an Andean orogen:Subduction alone does not lead to orogeny!
  72. 72. Aconcagua Structure Sections
  73. 73. Mendoza, Argentina: eastern foothills of the AndesOrganically poor desert soilswith scarce rains create idealconditions for quality viticultureBy controlling irrigation, the Mendoza winegrowercan influence vigor and hang-time
  74. 74. Mendoza Malbec Harvest TimeMendoza, ArgentinaApril 2006
  75. 75. Beagle’s last stop in South Americawas Lima, PeruDarwin enjoyed the ladies and aPeruvian custard apple called“chilimoya”September 7, 1835  Beagle steeredtowards the Galápagos Islands afterhugging the South American coast foralmost four yearsDarwin was 26 years old and highlyexcited
  76. 76. Charles Darwin & Reefs• Darwin, C. R. 1842, The structure anddistribution of coral reefs, Being the first partof the geology of the voyage of the Beagleunder the command of Capt. Fitzroy, R.N.during the years 1832 to 1836: London, SmithElder and Co.
  77. 77. Cocos (Keeling) Islands
  78. 78. • The Territory of the Cocos (Keeling) Islands is a territory of Australia, located in the IndianOcean, southwest of Christmas Island and approximately midway between Australia and Sri Lanka• The territory consists of two atolls and 27 coral islands of which two, West Island and HomeIsland, are inhabited with a total population of approximately 600• April 1st, 1836  Charles Darwin arrives aboard the HMS Beagle (Captain Fitzroy)
  79. 79. South Keeling Island
  80. 80. Progressive evolution:
  81. 81. Mount Tavurvur in Papua New Guinea
  82. 82. Fiji: Monukiri & Monu Islands
  83. 83. Maldives, Indian Ocean
  84. 84. Polynesia
  85. 85. Taiaro Atoll, French PolynesiaFirst visited in 1835 by Charles Darwin aboard the BeagleUNESCO protected area & Biosphere Preserve