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Stratigraphy

Stratigraphy. DEFINITION OF STRATIGRAPHY 1. Branch of geology that deals with definition & description of major & minor natural division of rocks... w/ the interpretation of their significance in geologic history.

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Stratigraphy

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  1. Stratigraphy • DEFINITION OF STRATIGRAPHY • 1. Branch of geology that deals with definition & description of major & minor natural division of rocks... w/ the interpretation of their significance in geologic history. • 2. Specifically, the geologic study of the form, arrangement, geographic distribution, chronological succession, classification & esp. correlation and mutual relationships of rock strata in normal sequence. • 3. It involves interpretation of these features of rock strata in terms of origin, occurrence, environment, thickness, lithology, composition, fossil content, age, history, paleogeography etc

  2. http://web.wm.edu/geology/virginia/provinces/Blueridge/blue_ridge_strat.html?svr=wwwhttp://web.wm.edu/geology/virginia/provinces/Blueridge/blue_ridge_strat.html?svr=www http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch11/ch_11_f.html

  3. Introduction • Beginning-(~1500AD) da Vinci saw fossils in rks of Italian Apennines • Concluded fossils once living marine organisms http://www.ucmp.berkeley.edu/history/vinci.htm

  4. Introduction • Steno- 1669-important contributor • Principle of Original Horizontality • Principle of Superposition • Principle of Lateral Continuity http://www.ucmp.berkeley.edu/history/steno.html

  5. Steno Principles • Lateral Continuity http://itc.gsw.edu/faculty/bcarter/histgeol/time/latcont.htm Superposition Original Horizontality

  6. Development of Sed Strat as Science • Organization of sed rocks—Arduino (1714-15) divided rocks • Primary Mtns-metallic ores no fossils • Secondary Mtns-Stratified, lithified, fossiliferous, no fossils • Tertiary low Mtns- Fossiliferous, unconsolidated gravels, sands clay, volcanics • Alluvium- Sediment washed down from mtns http://www.quaternary.stratigraphy.org.uk/about/history.html

  7. Development of Sed Strat as Science • Geologic Cycle and Uniformitarianism • James Hutton (1727-1797)-Scottish Physician, farmer • Noted cyclicity to earth’s behavior • Uplift, erosion, transport, deposition • Established Principle of Uniformitarianism or Actualism • present key to past but rates change and catastrophes occur http://www.ucmp.berkeley.edu/history/hutton.htm

  8. Development of Sed Strat as Science gsahist.org • Birth of Biostratigraphy & Stratigraphic Correlation • William Smith(1769-1839)-English surveyor, engineer • “father” of biostratigraphy • Canal builder noted relationship of fossils & rocks • Established law of faunal succession—fossils succeed each other in organized & recognizable fashion • Produced first geologic map

  9. Birth of Biostratigraphy & Stratigraphic Correlation • D’Orbigny (1842)-developed biologic stage for rock division • strata systematically follow each other with characteristic fossil assemblage • Oppel (1856)- developed biologic zone • Rocks deposited during existence of specific fossil • Zones based of first appearance of last appearance of organisms • Zones could be correlated

  10. Oppel Zones

  11. Development of Sed Strat as Science • Petrographic microscope development • Sorby began microscopic study of rocks • Led to description and systematic study of rocks • Geologic Revolution-Seafloor Spreading and Plate Tectonics • 1950-1960s- Renaissance period • More funds, more geophysical exploration, Deep Sea Drilling Project • More oil exploration

  12. New Tools • Magnetic and Seismic Surveying • Identification of normal/reverse periods led to magnetostratigraphy • Seismic surveying could identify units and unconformities, packages of related rocks • Isotope stratigraphy • Use carbon and oxygen isotopes to correlate units petroleum-gas.blogspot.com http://www2.ocean.washington.edu/oc540/lec01-28

  13. Magnetostratigraphy sp.lyellcollection.org

  14. Seismic Stratigraphy www-odp.tamu.edu

  15. Development of Sed Strat as Science • Sedimentary Rocks and Earth History • Paleoclimate • study of ancient climate

  16. Development of Sed Strat as Science • Sedimentary Rocks and Earth History • Paleogeography • reconstruction of area for given time in past http://jan.ucc.nau.edu/~rcb7 Wiley.com

  17. Development of Sed Strat as Science • Sedimentary Rocks and Earth History • Paleoecology & Evolution • studies relationships between ancient organisms & their environments http://scienceblogs.com/laelaps/Futalognkosaurus%2Bmural.jpg

  18. Development of Sed Strat as Science • Sedimentary Rocks and Earth History • Paleoceanography & Ancient Atmosphere • Composition of ancient oceans and atmosphere using isotopes http://www.jamstec.go.jp/rigc/j/ebcrp/paleo/

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