Mesozoic Earth ] Back | Next >

 North America
 75 million years ago

Mean atmospheric O2
 150% of modern level

Mean atmospheric CO2
 6x pre-industrial level

Mean temperature
 4C above modern level

Mesozoic Earth - The Western Interior Seaway as seen from Earth orbit 75 million years ago; the Cretaceous Seaway; the Niobraran Sea; the North American Inland Sea; Earth from space; plate tectonics; lithosphere; seafloor spreading; continental drift; tectonophysics - Natural History Illustration Geologic Time Scale

 Era: Mesozoic
  Period: Cretaceous
   Epoch: Late
    Age: Campanian


Western Interior Seaway

This is how the Western Interior Seaway may have appeared 75 million years ago from Earth orbit. This large inland sea once divided the North American continent into two landmasses, Laramidia to the west and Appalachia to the east. Branching toward the northeast is the Hudson Seaway and to the north on the horizon are the liquid polar waters of the Labrador Seaway.

At less than one-fifth the size of present day North America, the island continent of Laramidia extended from present-day Mexico to Alaska and was home to tyrannosaurs, dromaeosaurids, troodontids, hadrosaurs, ceratopsians, pachycephalosaurs, and titanosaur sauropods.

The dinosaurs of Appalachia are less-understood as much of the fossil evidence was destroyed by the glaciers that alternately descended from the north and retreated starting 2.5 million years ago.




Copyright Walter B. Myers. All rights reserved.

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