Category Archives: Paleogeography

Entropy and the Grand Canyon II

We left off in the last post having boated 78 miles, about five days on a typical trip, and having encountered the last of the suite of three books that comprise the geological story revealed in the Grand Canyon. We … Continue reading

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Entropy and the Grand Canyon

It has been our good fortune to row 280 miles of the Colorado River through the Grand Canyon twice in the last seven months. This is rare for private boaters limited to one trip per calendar year and subject to … Continue reading

Posted in Geology, Paleoclimate, Paleogeography | 1 Comment

Differential Motions of the Continents, Mesozoic and Cenozoic Eras: The 120mya Inflection and Finale

A square kilometer of extruded ocean floor exerts force in all directions. The “squareness” is partly our own construct for convenience of measurement, but also justified by lateral offsets where the linear ruptures we call ridges accommodate the curvature of … Continue reading

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Differential Motions of the Continents, Mesozoic and Cenozoic Eras V: The 80mya Inflection

In the last post on constraints we decided that the east Pacific and Juan de Fuca ridges were useless in constraining the motions of the Americas. We decided that the Atlantic, Greenland, and Lomonosov ridges were acceptable explanations for the … Continue reading

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Differential Motions of the Continents, Mesozoic and Cenozoic Eras IV: Constraints

We know the position and velocity of stable points on our six cratons. A reasonable question to ask is, “Can we account for this motion?” Above is a map of the ocean floor created in the last 10 million years. … Continue reading

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Differential Motions of Continents, Mesozoic and Cenozoic Eras

The total volume of ocean floor production becomes increasingly difficult to constrain as we work backwards in time. Ocean floor is increasingly lost to subduction, and efforts to replicate the missing parts become speculation. The continents, by contrast, have grown … Continue reading

Posted in Continental Wander Path, Paleogeography | 2 Comments

The Cretaceous Superchron, Beaufort Isochrons, and the Motion of North America

In the last post we explored a very peculiar set of seafloor isochrons in the Beaufort Sea and Arctic ocean. We found that a perpendicular shift in seafloor spreading defined the Cretaceous Normal Superchron, the longest known period in earth … Continue reading

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