Plate Tectonics and the Fossil Record

Two questions and perspectives that we will explore:

The first question was more important during early arguments on continental drift and the second has become more important as plate tectonics has been accepted.

Some background on history of life on earth you can delve into.

Biogeography a critical discipline here - geographic distribution of organisms and why?

Example of a biogeographic map. Note the latitudinal control. However, also not the departures from a strict latitudinal control. At least some of these departures reflect tectonic topography. Image source: USGS - http://gapanalysis.usgs.gov/species/news/ .

What environmental factors influence biogeographic distribution?

Two important concepts within:

Glossopteris leaf fossil - one of the fossils common to Pangea continental partners - an example of the information available in documenting paleobiogeographic distribution. This particular sample is from the Ellsworth Mountains of Antarctica. Image source: (Photo Credit USGS DDS21) as found at http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/tectonics_landforms/tectonics_evidence.html


Exercise: Supercontinents and biogeographic patterns. Gondwana and Pangea are large continental masses (super continents) that formed and split apart. So in addition to the Wilson cycle, which explores the type of history we would expect on a continent scale, there is a proposed supercontinent cycle that is thought to have occurred on a global scale. Break up into groups of four and work on developing a cycle diagram that depicts how biogeographic patterns would change with the continental configuration, a la the Wilson and supercontinent cycle. Think of different types of organisms: marine vs. terrestrial is a major distinction, but there are others. After fifteen minutes, a spokesperson will present the groups results to the class.

The Mesozoic world was a time of supercontinent dispersal . How might of this affected the history of life? Source of image - USGS publication - Dynamic Earth.

Hallam's faunal assemblage behavior in plate tectonics context:


Dispersal mechanisms:

Barriers to migration:


A few lessons from the present day biogeography.

More diversity in warmer climates than colder for terrestrial organisms, but not necessarily for marine organisms.

A variety of ant eaters:

Wallace's line:


Examples in the fossil record:

De Geer Route of mammal dispersal (based on McKenna, 1975).

Gondwana associated examples:

Panamanian isthmus related examples:

Two faunal provinces of Cambrian trilobites on either side of the Caledonides, but by Silurian they converge ­ Caledonide ocean narrow enough. Trilobites informative in general.

Ural moutains in Russia:


A paper waiting to be done? - what is the role of suspect and exotic terrance tectonics in biogeographic behavior.

Role of mantle convection and hotspots?

Origin of life and submarine hot springs and black smokers?

Idea that plate tectonics influenced hominid, and therefore human evolution?


Some links:

Paleo Integration Project (PIP) - still in development.

Trilobite paleogeography.

References:


Course materials for Plate Tectonics, GEOL 3700, University of Nebraska at Omaha. Instructor: H. D. Maher Jr., copyright. This material may be used for non-profit educational purposes with appropriate attribution of authorship. Otherwise please contact author.