Does the Eocene-Oligocene Transition mark the end of the global flood?
In the Genesis flood model, the geologic record (at least of the Phanerozoic) are the remains of a catastrophic global flood and associated tectonic upheaval, followed by an extended period of aftershocks or regional catastrophes as the waters receded from the continents and life began to repopulate a gradually stabilizing earth.
Paleozoic, Mesozoic, and lower Paleogene rock layers are globally catastrophic depositions, or the mass annihilation of the pre-Flood world's ecosystems.
It is at the Eocene-Oligocene Boundary, or EOB, (at about 34 million years ago in the Evolution model) where we see a shift from past global catastrophe to an unfolding of what are now "modern" ecosystems. This phenomena may record the earth being repopulated by land animals migrating from the Ark, as well as the continents becoming seeded with vegetation and other small organisms drifting along ocean currents.
At this boundary, we find a major trend of new types of animals filling out Asia and Europe with a pronounced mammalian faunal replacement..
These patterns are so dominant that researchers have given them names like the "Asian Biotic Reorganization" in Asia and simultaneously, the "Grand Coupure" in Europe.
Eocene–Oligocene extinction event - Wikipedia
"
Evidence in the world’s ocean current system indicates an abrupt cooling from 34.1 to 33.6 Ma across the Eocene–Oligocene boundary at 33.9 Ma. The remarkable cooling period in the ocean is correlated with pronounced mammalian faunal replacement within continental Asia as well. The Asian biotic reorganization events are comparable to the Grande Coupure in Europe and the Mongolian Remodeling of mammalian communities. The global cooling is also correlated with marked drying conditions in low-latitudes Asia."
Some other notes from the secular literature:
From "The Eocene-Oligocene Transition" by Coxall and Pearson 2007
"
It is interesting that in groups as diverse as foramnifera, primates, whales, and birds, the Oligocene saw the diversification of recognizably modern taxa,whereas most of the Eocene forms are from prehistoric now-extinct groups.....The whole Earth system seems to have entered a period of prolonged change, a factor that makes the Eocene-Oligocene boundary extinctions rather different from the more sudden mass extinctions at the end of the Cretaceous and probably the end of the Permian as well."
"The weight of fossil and climate evidence strongly indicates the Late Eocene to Early Oligocene as a time of major global climate change, with many implications for marine and terrestrial ecosystems... Unlike the Cretaceous-Paleogene or Permian-Triassic boundaries, there is no indication of a sudden catastrophic event: rather, fossil records document a pattern of enhanced yet gradual turn-over, signalling adjustment to changes in food and nutrient availability, habitat, and climate-regime."
Some other papers:
"Faunal Turnovers of Paleogene Mammals from Mongolian Plateau" - Meng 1998
"Eocene-Oligocene Transition in Central Asia and its Effects on Mammalian Evolution" Kraatz 2016
"Synchronous Turnover of Flora, Fauna, and Climate at the Eocene-Oligocene Boundary in Asia" - Sun 2014
The last article notes a "remarkable" change in pollen and abrupt increase in grasslands as the climate gets cooler and drier....
We find open grasslands appearing all over the world.
As well as:
- Large-scale aridification or drying
- Significant drop in sea-level
- Major reorganization of the ocean currents
These are all trends we would expect to see around the same time that the "modern" land animals are appearing on the scene as they migrate across a post-flood world.
So that's the idea.
A question arises, why don't we also see pre-flood versions of these "modern" ecosystems that were deposited by the flood before this post-flood transition began to take place?
The flood would have overtaken ecosystems in a basic step-wise fasion.. starting at the deep ocean floors (but not necessarily the open ocean swimmers or inland seas), and working its way up coastlines, and swampy wetlands, and finally the drier uplands where we find much of these same types of ecosystems today. These ecosystems would have been deposited in the upper most rock layers. It is then hypothesized that much of these top layers were then scrubbed off the continents when the global floodwaters began to recede, to be replaced by post-flood sedimentary layers. This is why we don't find an ecosystem of "modern" mammals (or humans) buried in rock layers directly below the post-flood layers where those same types of animals were repopulating the earth.
Importantly, as the post-flood world is repopulated, ecosystems still undergo many smaller, regional catastrophes associated with residual tectonic and volcanic activity, as well as regional floods resulting from natural dam-breaks and drainings of in-land lakes or seas that were left over.
Extinct paleozoic and mesozoic land animals would have been included in these post-flood migrations. Any land animal type's absence tells us they were relatively unsuited for the post-flood world, either through predation or other ecological factors, and their populations may have been endangered from the outset. This may be related to the reason they were buried in these lower rock layers to begin with, that these extinct animals lived in far more segregated pre-flood biogeographic realms, and their success levels plummeted in a drastically changed post-flood world.
(Point of clarification: in this flood model we obviously reject the convention of geologic time. Instead, the Paleozoic-Mesozoic layers were deposited in the span of a year-long flood. And the Eocene-Oligocene transition did not actually happen 30+ million years ago, but within the last several thousand years.)