Plate Tectonics Flooded North America

In a radical departure from conventional ideas,
geologists affirm key mechanisms of Biblical Flood models

In recent presentations hosted by Logos Research Associates, creation geologists with PhDs have given detailed models for how the Biblical Flood happened. These presentations are available on YouTube:

• Dr John Baumgardner modeled how runaway subduction caused tsunamis across the world that deposited sediments and fossils.
• Dr Tim Clarey modeled how the major global megasequences of strata were deposited at stages of the Flood year.
• Dr Steve Austin gave details about a sudden mass kill event recorded in the Redwall Limestone that buried billions of nautiloids and corals at one stage of the Flood in a fast-moving underwater debris flow. He supplied field data he collected over 35 years in widely scattered areas in and around Grand Canyon.

Creation geology models like these are typically ignored by secular geologists. Tied at the hip to evolutionary biology, secular geology interprets everything in a framework of Deep Time (billions of Darwin Years) and scoffs at ideas of Biblical creation and young earth, just like the apostle Peter said people would in the last days (II Peter 3:1-8).

Nevertheless, field data and rock layers are out there for anyone to see.

Volunteer points to Great Unconformity, as Dr Andrew Snelling and Tom Vail look on. Above the unconformity is the Tapeats Sandstone, the first sedimentary layer above bedrock, and lowest member of the Sauk Megasequence. Photo by David Coppedge, June 2008.

This month, two geologists at University of California in Santa Barbara (UCSB) shared their model about how the first sedimentary layers in the Sauk Megasequence were laid down above basement rock. This megasequence begins at the Tapeats sandstone above the Great Unconformity, visible at many places in the Grand Canyon as a sharp boundary between igneous granite overlaid by sediments containing Cambrian fossils. Their model? Subduction at continental margins raised sea levels that flooded North America. This sounds remarkably similar to the Flood model presented by Baumgardner, except for the time frame: these secular geologists stretch the flood out over millions of years.

Phanerozoic flooding of North America and the Great Unconformity (Tasistro-Hart and Macdonald, PNAS, 5 Sept 2023). The paper mentions the word flood over a hundred times. The “significance” of the paper, summarized at the top, mentions that it was caused by subduction at continental margins:

Marine sediments across North America record multiple flooding events over the Phanerozoic, starting with the Sauk Transgression that seals the Great Unconformity. Using Macrostrat, a geospatial database of stratigraphy, we demonstrate that these flooding events, except the Sauk, correspond temporally and spatially with subduction under North America, consistent with near-field dynamic subsidence. We suggest that the Sauk resulted from the migration of subduction zones from oceanic to continental arcs around Gondwana, which flattened global hypsometry and displaced ocean water onto North America. Our analysis links the Phanerozoic flooding of North America to local and global tectonics and suggests that sea level is set by the amount of oceanic spreading that is balanced by subduction under continental relative to oceanic lithosphere.

Creation geologists say that one flooding event, the Genesis Flood, accounts for all the sedimentary layers—not “multiple flooding events.” As shared at this site previously by Bill Hoesch, ten evidences show that the one Flood explains the data. These include the flat pancake-like stacks of sedimentary layers without evidence of surface erosion, and the fact that multiple strata folded simultaneously while they must have still been soft. Evolutionists have no explanation for multiple gaps of millions of years at four major unconformities in the Grand Canyon:

To believe the evolutionary timeline, you have to accept multiple huge time gaps. And yet all the strata sit conformably on top of one another, with no evidence of millions of years of erosion between them. The bottom gap shows the position of the Tapeats sandstone above the Great Unconformity.

Moving along without mentioning these discrepancies for deep time, the two secular geologists postulate that a global event triggered the flood over North America when the “Sauk Transgression” began:

The sole Phanerozoic exception to this pattern of global sea level tracking North American near-field geodynamics is the Cambrian Sauk transgression. We argue that this is a far-field record of the inception of circum-Gondwanan subduction, independent of North America, which significantly flattened Earth’s hypsometry. This hypsometric flattening displaced ocean water globally, flooding tectonically passive North America to seal the Great Unconformity.

They’re getting warmer. This is a far cry from older models by secular geologists that pictured slow, gradual processes according to Lyell’s principle of uniformitarianism. Now, they allow for global events with major consequences for a large continent.

Can flooding a continent take place because of activity at a distant source, like seafloor spreading at an oceanic ridge? Can this take place faster than expected? The laws of physics prevent this—unless special circumstances occur to raise sea level. But that’s what happened to flood North America. Tasistro-Hart and Macdonald say:

The globally averaged rate of oceanic spreading is frequently portrayed as the dominant control on long-term global sea level (eustasy). A longer total ridge length, or faster-spreading ridges, generates more young, warm, and therefore buoyant oceanic lithosphere, elevating ocean basins and displacing sea water onto continents (13). This Pitman model of sea level, however, must conserve mass: If ocean basins go up, then some other part of Earth’s surface must go down (14). From this perspective, if elevated oceanic lithosphere in one part of the globe is entirely compensated by subsiding oceanic lithosphere elsewhere, then the net effect on sea level is zero. Increased spreading rates must be complemented by a geodynamic mechanism for subsiding land masses above sea level in order to increase sea level (14) (Fig. 1). An obvious candidate for this geodynamic coupling is subduction along continental margins, which can cause dynamic subsidence of continental lithosphere above descending slabs (10). A slab subducting under continental lithosphere, creating a continental arc, can contribute to both local and global sea level rise, whereas a slab subducting under oceanic crust, creating an oceanic arc, cannot.

Figure 1 in the paper shows how “increased spreading rates” can reach a “fulcrum” or tipping point, like a “see-saw” (their phrase*), making water spread out onto a continent. If this is the explanation for the onset of the Sauk Megasequence, then it was not uniformitarian. It was an exception. A “faster-spreading ridge” caused subduction under a continental lithosphere, raising sea level and sending water over North America. Sounds rather catastrophic.

Dr Steve Austin, creation geologist, points out the position of the Great Unconformity near Pikes Peak along the Colorado front range. The Great Unconformity can be traced around much of the globe, signifying a world-wide cataclysm. (Photo by DFC, 11/2015).

It’s a new idea, they say, that fills in a gap in secular geology: a geodynamic grounding or physical cause for the stratigraphic record. “Dynamic and tectonic subsidence are often treated independently from global sea level,” they admit, but that causes problems with the record.

Our argument linking the Phanerozoic flooding of North America, including the Sauk Transgression and the Great Unconformity, to the local and global distribution of subduction under continents provides a previously lacking geodynamic grounding. This new link reconciles the relative roles of near-field tectonic basin formation and far-field geodynamics on the distribution of the rich stratigraphic record that crowns North America.

The only question now is the rate at which this happened, and whether it is tied causally to the other “multiple flooding events” that laid down the subsequent layers. See Clarey’s presentation for a Genesis Flood interpretation of all the megasequences, many of which are world-wide.

Abruptness of the Great Unconformity is evident throughout the Grand Canyon, where it is extremely flat. Yet evolutionists insist a billion years of geology took place between the basement bedrock and the overlying sediments. (Photo by DFC in Blacktail Canyon, Grand Canyon, 2007)

This paper should be of interest to creation geologists. It’s pretty exciting to see two geologists at a secular university start entertaining the thought of global causes with global effects (the word “global” appears 44 times in the paper). “Refinements to plate reconstructions coupled with dynamic topography models, along with development of spatial flooding datasets on continents besides North America, will provide future tests of our model,” they say. Good. Think outside the uniformitarian box and start considering all the other evidences for rapid sedimentation around the world.

*Another quote from the paper:

The global dynamic topographic response to this subduction has been shown by the mantle convection model of ref. 67, who demonstrate the kilometer scale subsidence over the entirety of Gondwana and complementary topographic highs concentrated in the proto-Tethys and proto-Pacific Oceans. Although ref. 67 do not show flooding of North America at 520 to 480 Ma in their C1 reconstruction (their Fig. 4), this is a product of the assumptions in the plate reconstruction, whereas the M21 reconstruction produces strong far-field flooding (their Fig. 9). This result is precisely the hypsometric see-saw by which enhanced continental subduction lowers the continents and is balanced by enhanced seafloor spreading that raises the oceanic lithosphere, raising sea level globally and driving the Sauk Transgression.