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Paleobiogeography

Paleobiogeography. What is it?. Studying geographic distributions of fossil organisms So what? Biostratigraphy – correlating between biotic provinces Paleogeography – tracking sea level changes, reconstructing plates and continents Paleoclimatology – using organisms to track climate.

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Paleobiogeography

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  1. Paleobiogeography

  2. What is it? • Studying geographic distributions of fossil organisms • So what? • Biostratigraphy – correlating between biotic provinces • Paleogeography – tracking sea level changes, reconstructing plates and continents • Paleoclimatology – using organisms to track climate

  3. Water Masses • “Bodies of ocean water with relatively uniform conditions of temperature and salinity • E.g.: California Current, Central Pacific Water

  4. http://oceanmotion.org/html/background/timeline1978-88.htm

  5. Implications: • Geographic distributions of organisms can reflect boundaries of water masses • Equatorial currents act as dispersal barriers to marine organisms (cold water critters can’t cross equator) • Ocean currents depend on: • Continental positions • Heat budget of Earth • And so does the geographic distribution of organisms • So mapping the organisms can map ancient ocean water masses and currents

  6. Tectonic processes affect the distribution of organisms • Creation/elimination of dispersal barriers • E.g. Opening of Atlantic is barrier to land organisms, pathway for marine organisms • Changes in ocean currents • Changes in basin depth & therefore sea level • Changes in climate – continentality promotes extreme terrestrial climates

  7. Implications • Plate distributions can explain organism distributions • E.g., Tethys organisms • Organisms can be evidence for plate reconstructions

  8. Examples • Gondwana reconstructions • Mesosaurus – freshwater lizard • Glosspteris – tropical flora • “Viking funeral ships” – dead when the continents separated

  9. http://www.mrsciguy.com/sciimages/fossil_record.gif

  10. Examples • Gondwana reconstructions • Mesosaurus – freshwater lizard • Glosspteris – tropical flora • “Viking funeral ships” – dead when the continents separated • Baja rifting • Legless worm lizard • “Noah’s ark” – range separated while species was extant

  11. Examples • Exotic terranes: • Late Paleozoic to Meoszoic California (and the ret of the Cordillera) is made of many accreted terranes – • As small as island arcs from subduction zones • As large as continental fragments • Evidence • Lithologic • Paleomagnetic – magnetic declination & inclination • Fossils – tropical fusilinids in Permian rocks

  12. http://plate-tectonic.narod.ru/terranesswamerphotoalbum.html

  13. Organisms & Climate • Distribution of organisms is affected by climate & climate change • If you know the biology, you can infer the climate: pollen • If you know the climate (using other evidence – isotopes, pollen), you can infer biology: high latitude dinosaurs & homeothermy • Maybe we can use past climate & biogeographic shifts to predict the current change • What happened in interglacials? Where to the climate & vegetation belts go?

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