Where is the Post- Flood Break?

"The present distribution of living organisms is the consequence of numerous Flood-and post-Flood

related events. For those nephesh creatures taken aboard Noah’s Ark, the biogeography of the modern species is primarily reflective of the migration and/or transport of original Ark-borne progenitor animals from the mountains of Ararat combined with intrabaraminic diversification (e.g. speciation).
Whether baramins are best reflected at lower taxonomic levels (e.g. genera) or are more inclusive (families or higher taxonomic categories), intrabaraminic speciation events may be recorded in post-Flood sediments, leaving a fossil record of diversification within baramins leading to the present.

Evaluation of this record is the domain of biostratigraphy, the branch of paleontology dedicated to discovering the patterns of fossil occurrences within vertical sections of sedimentary rock.

While a number of criteria have been offered for determining the location of the Flood/post-Flood boundary, there remains as yet no consensus. Opinion is primarily (though not entirely) split between a boundary at or near
*the Cretaceous/Paleogene (= Tertiary) or
*the Pliocene/Pleistocene divisions.
I submit that a robust biostratigraphic analysis aids in determining the location of the Flood/post-Flood boundary, since a pronounced biostratigraphic break marking the termination of the Flood should be expected by all creationists. The reasons are as follows.

1. Since the pre-Flood distribution of continents was markedly different than the modern distribution, pre-Flood ecosystems from any given continent would be significantly different from those found on that same continent after the Flood.
2. Even if the continental configuration was identical to today (which is unlikely), the majority of young-earth creationists maintain that Earth’s climate was more equitable, particularly in (presently) temperate and polar regions. Hence pre-Flood organisms borne by the Ark would face differing climates upon their return to the same continent and latitude. Such climatic differences would only become more pronounced leading up to and throughout the post-Flood Ice Age (which, in accordance with ‘high’ boundary placement, occurs very shortly after the end of the Flood).
3. As a result, it is unlikely that the post-Flood dissemination of animals would result in a return to their pre-Flood geographic locales. In other words, it is unlikely that species of baramins taken aboard the Ark would display a proclivity to migrate to the graveyards of their deceased, pre-Flood baraminic kin.

Regardless of the initial continental configuration, the following must be true if the Flood/post-Flood boundary is placed at or near the Pliocene/Pleistocene boundary: North American fossil taxa must have either inhabited the locations of their present fossil deposits (in North America) prior to the Flood, or they must have been transported exceptionally long distances en masse to North America during the Flood.

From the dissemination of nephesh kinds released from the Ark, one would also expect that the post-Flood baramin representatives would follow a ‘sweepstakes’ pattern of opportunistic migration and inhabitation of the new post-Flood world and its varied environments. Given this and the above-

mentioned differences in climate, there would likely be no preference for any particular baramins to migrate back to the starting locations of their now-deceased, pre-Flood kin.

But what if the Flood/post-Flood boundary is not/ cannot be placed at a particular geologic location? That is, what if the Flood ended in one location that geologists call ‘Eocene’ and elsewhere in the ‘Pliocene’? While this may be possible for certain deposits (e.g. the marine sediments of the southeastern United States display a marine → terrestrial transition reflective of continual sea level drop through much of the Cenozoic; in this case, some areas may be post-Flood earlier than other, still-inundated areas), it is unlikely to apply here. In North America, the vast majority of the mammals evaluated here are found in sedimentary deposits from regionally restricted terrestrial basins, rather than trans-continental sedimentary deposits likely to be formed under Flood condition. This fact was part of the rationale for placing the end of the Flood near the Cretaceous-Paleogene (= Tertiary) boundary by Austin et al. in their description of Catastrophic Plate Tectonics.

Methods

Selection of North American mammals

Ideal groups to test the argument for a Pliocene/ Pleistocene location for the Flood/post-Flood boundary are North American mammals. These groups benefit from a long history of intensive, well-documented collection and study.

Creation of biostratigraphic range charts

North American mammalian families were tabulated and analyzed using the Paleobiology Database. The Paleobiology Database is a collaborative online repository of paleontological information. In particular, the Paleobiology Database includes taxonomic, biogeographic, and biostratigraphic data for fossils described in the professional paleontological literature and curated in museums and university repositories.

For this analysis, mammalian families were chosen from the following Orders: Artiodactyla, Carnivora, Edentata/Xenarthra, Insectivora, Lagomorpha, Marsupialia, Perissodactyla, and Proboscidia. Each of the families selected from these orders contain genera that are either extant or cross the Pliocene/Pleistocene boundary, and therefore exist until the Ice Age, which is recognized by creationists to be a post-Flood event.

Figure 2. Correlation diagram of Cenozoic periods and epochs with North American Land Mammal Ages (NALMAs). Figure produced with TSCreator.

To conduct the analysis, I employed the following methods:

1. From the main page at www.pbdb.org, the ‘Count taxa’ tool from the ‘Analyze’ tab was selected to create a list of the fossil genera within each queried family. I entered the family name (e.g. Canidae) into the ‘Taxonomic group’ box. I then clicked ‘Submit Query’, and the tool produced a list of genera and species.
2. I copied and imported this list of genera into the ‘Analyze taxonomic ranges’ tool, which builds biostratigraphic range charts from known fossil occurrences, generated from the published literature and records from museum collections. After entering the genus list, I selected ‘as entered’ in the ‘Break taxa into’ box and submitted the query.
3. The next page which loads is the ‘Confidence interval options’ page. Under ‘Time scale’, researchers can choose among a number of biostratigraphic methods for graphical output. I selected ‘North American Land Mammal Ages’ (see below for discussion).
4. On this same page, I selected ‘no confidence intervals’ under the ‘Estimate’ box. This retrieves only the raw occurrence data, with no statistical estimates on biostratigraphic ranges above or below documented first and last appearances.
5. For visual ease of evaluation, I selected ‘last appearance’ for the ‘Order taxa by’ box and submitted the query.

Standard geological chronology vs North American land mammal ages

I evaluated the differences in reporting which result from selecting two timescales applicable to the Cenozoic mammal record of North America:
stages (e.g. Eocene, Oligocene, Miocene) and North American Land Mammal Ages (herein NALMAs). The NALMAs are a biostratigraphic system used primarily for the Cenozoic of North America, built upon biostratigraphic relationships among mammals (there are several late Cretaceous NALMAs as well; they are not employed in this evaluation).

Results and analysis

The position of the Pliocene/Pleistocene boundary (dated at 2.6 million years ago by conventional geologists) correlates to the upper portion of the Blancan NALMA.
For ease of evaluation, the boundary between the Blancan and overlying Irvintonian NALMA will serve as a proxy for the Pliocene/Pleistocene boundary. Genera known from the Irvingtonian NALMA that also record fossils from the Blancan NALMA or below are considered to cross the Flood/ post-Flood boundary when placed at the Pliocene/Pleistocene. Any genus whose highest occurrence is within the Blancan is not considered to cross the boundary. Of the 303 genera surveyed, 70 (23%) cross the Pliocene/Pleistocene boundary.

....the output generated for the family Antilocapridae, and serves as a guide for interpreting these figures. Fossils of this unusual ungulate family (which have a bony horn capped by antler material) are found only in North America, and the family is represented today by the lone species Antilocapris americana, the pronghorn antelope. .....Antilocapris is accompanied by sixteen additional genera from Antilocapridae during the Cenozoic.

A dashed line marks the boundary between the Blancan and Irvingtonian NALMAs, the proxy for the Pliocene/Pleistocene boundary. Of the seventeen total genera, four cross the Pliocene/Pleistocene boundary.

When the Pliocene/Pleistocene boundary is used to approximate the Flood/post-Flood boundary, nearly one-fourth of the post-Flood baramin members (understood to be species within the same genus) evaluated here migrated from North America to the Ark, and returned again to North America to coincidentally inhabit the same geographic locations as their pre-Flood (or transported, Flood-buried) baraminic kin.

If pre-Flood baramins are better approximated by the taxonomic rank of family (which is more reflective of current baraminological research and rather broad consensus within the young-earth community), then the situation is far more severe. Twenty-seven of the 28 mammal families studied here include at least one genus which crosses the Flood/post-Flood boundary when placed at the Pliocene/ Pleistocene boundary, and many families display multiple boundary-crossing genera. The lone exception is the Rhinocerotidae, the last members of which in North America suffer extinction during the Pliocene. So if the family approximates the baramin, then >96% of the mammal baramins evaluated here migrated from Laurentia/North America to the Ark, and returned again to North America.

Moreover, taxa which would have had to return to North America are in some cases genera known only from North America (e.g. Antilocapris (pronghorn antelope), Odocoileus (whitetail and mule deer), Sylvilagus (cotton-tail rabbits)). For these taxa, there is no pool of species from their genus on other continents which could coincidentally migrate to North America during the post-Flood period. In other words: why would endemic pre-Flood North American mammals return only to North America? One would expect, given the ‘sweepstakes’ model of post-Flood migration, that pre-Flood baramins currently known from the Cenozoic of other continents would appear above the boundary as Pleistocene fossils in North America. While it is certainly true that there are a number of genera which appear to migrate from Asia and Europe (especially bovids) and South America (a number of edentates/xenarthrans), these taxa are themselves known from more recent geological strata, rather than from deeper within the Cenozoic, or below. This supports a Flood/post-Flood boundary significantly lower than the Pliocene/ Pleistocene, with the Cenozoic faunal interchanges and significant endemic development reflective of post-Flood migration and intrabaraminic diversification.

Conclusions
The biostratigraphic analysis presented here for North American mammalian families makes

placement of the Flood/post-Flood boundary at or near the Pliocene/Pleistocene boundary untenable. Rather, these data are more naturally interpreted as representing time-sequential recolonization of the post-Flood world by diversifying terrestrial mammal baramins. Given the biostratigraphic break expected to characterize the Flood/post-Flood boundary, a lower location for the boundary must be sought. At present, the Cretaceous/Paleogene boundary appears to be the stratigraphically highest and most prominent biostratigraphic break (it includes the last inplace stratigraphic appearance of dinosaurs, pterosaurs, and several other bird, mammal, reptile, and amphibian groups), though a similarly thorough analysis must be completed in order to strengthen its claim to the Flood/post-Flood boundary." CMI

Every beast, every creeping thing, and every fowl,

and whatsoever creepeth upon the earth, after their kinds, went forth out of the ark.

Genesis 8:19