Marine Regression Theory - Dinosaur Extinction
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Extinction > Marine Regression Theory
Marine regression suggests that many areas of the terrestrial realm were repeatedly inundated by shallow epicontinental seas throughout geologic history. These inundations occurred in very shallow seas upon the continental shelves and platforms rather than in deep ocean basins.
It is known that during the Late Cretaceous Period, large areas of continents were submerged under shallow epicontinental seas.
The loss of shallow seas increased by more than 25% during this time period, this is the equivalent of adding the land area of all of Africa, the second largest continent nowadays.
Some of the most dramatic additions of nonmarine areas at or near the K-T boundary occurred in North America. Near the Cretaceous, maximum transgression divided North America into two continents.
As this transgression continued, costal plains decreased in size and became fragmented. The repeated inundations or transgressions is not fully understood. The idea is that it may be the result of plate tectonics.
This drastic reduction of costal plains put tremendous pressure on some, especially large vertebrate species. The shrinking of coastal plains of latest Cretaceous North America affected the dinosaurs.
By having this coastal fragmentation caused the reduction of flow of species from one fragment to another. The results can be disastrous if viable populations cannot be maintained in the various fragments. Scientists believe that fragmentation can lead to extinctions.