Carolina Bays as Medial Ejecta
The Ejecta Depositional Conjecture holds that a sheet of ejecta debris - a slurry of water and sand/silica - was deposited across an arc down range of the Saginaw impact. The sheet exhibits a surface texture of "splatter" marks, which have evolved into today's Carolina bays. The sheet of material is proposed to be quite "thin"; only a few meters of ridge around our splatter mark will hold water. We emphasize that our conjecture does NOT suggest that the bays are either primary or secondary impact structures, but rather exist within a blanket of ejecta material. … Well, at least that is one of many working hypothesis as to how the basins were formed in the ejecta sheet.
We speculate that glacial ice, excised sedimentary strata beneath it in Michigan, and the impactor, would effectively shatter into small particles and intermix in the ejecta curtain wall. The hypothesis holds that from this event a 1-10 meter-thick layer of Medial ejecta was spread across the continent. At a certain distance from the crater - seen empirically as 850km to 1300 km - constituents of fine to medium sand was willowing out of the ejecta curtain wall. It was hot, and very hydrous. Effectively we see this as being a frothy mixture that created the bays as bubbles of gas deflated during deposition. The visualization of bays, both in size and juxtaposition clearly represents a physical fractal distribution.
While the majority of inquiries into the bays have been accomplished by probing their interiors, the hypothesis suggests that they are but voids within the ejecta sheet, and the real action is actually between the bays. Many Carolina bays possess classic lacustrine sediment stratigraphy and enclosing shoreline sediments, which is fully appropriate for a basin existing for tens of thousands of years in areas of high water tables.
The standardized template used to identify and validate a proposed structure is shown below. The outline is used by us in the Google Earth facility as an overlay to discriminate ejecta deposits.
The geomorphic signatures seen in these structures are many, and no other deposition method has been implicated satisfactorily. Arriving from the upper left in the image below, the sheet of debris slammed into the terrain, and spread across areas of varying elevation. Within a few hundreds of meters, we see Carolina bays created at significantly different elevations, as well as having them overlaid and/or partially obscured by additional material arriving moments later. All "Carolina bay" fields we have been able to identify are positively for correlated to a cosmic impact as causal source.
Co-located Bays seen at significantly different elevations
The situation is similar out to the west. The Clay Center, Nebraska area has a significant emplacement of "Carolina bay" ejecta structures. In this case, the elevation differences are even more striking. In the graphic below, we see bays of similar alignment spanning an elevation difference of 40 meters in the range of 30 km. Obviously these are not likely former oxbows in a lazy river.
An extensive display of the "fields" we have investigated in Google Earth is available on the “Bay of the Day” page. Links to kml files for use in Google Earth is available there, also.
With an incoming velocity of close to 1,000 km/hour, the slurry surged forward at impact and created slightly higher rims on the SE end of the splash bay. The ground speed difference effect driven by the latitude delta between the Michigan ejection point and the deposition location would have subtracted from any west-to-east velocity component. The result would be expected to distort the surficial bay features along the E-W axis, which has been reported:
: (1)"Many bays, however, lack true bilateral symmetry along either the major or minor axis. ….the northeast side bulges slightly more than the southwest side.
Along with the compression, we believe the inferred orientation of the bay becomes skewed from its expected arrival direction. This effect is referred to by us as "systematic by latitude", as the effect is a function of the latitudes involved.
Here are a few photos showing this very common compressional artifact.
Other supportive details include the well-understood fact that, universally, the soil layers containing the bays are superimposed on underlying strata at a sharp and "abrupt comfortable" interface that shows no interbeding.
Much of the current research identifies the strata as consistent across wide areas, both within single and multiple bays.
No variation in the heavy mineral suite was found along a traverse of the major axis of one South Carolina bay; even though samples were taken from the bay floor, bay rim and the adjacent non-bay terrace (Preston and Brown, 1964).
Our conjecture holds that a major component of the ejecta slurry was terrestrial strata from the Michigan Basin area. This quote from a web page at Clemson University makes some interesting comments:
While the surface color can be bright enough to appear almost white, the color of the "B" horizon layer is often brown or black, like topsoil, but it is found about four feet below the soil surface. [Soils of this type are usually found in northern regions, like New England, Northern Michigan, Minnesota, and Canada.] For several reasons, including acidity and possible aluminum toxicity, this is not a good soil for plant growth and is only sparsely covered by scrubby pines, blackjack oak, and turkey oak.
When presented with the ejecta strata concept in 2006, noted soil geologist R.B. Daniels observed that the conjecture, while hard to embrace, did address one ongoing enigma of the bays (and Goldsboro Ridge in particular): The unconsolidated deposits that constituted the rim bays did not contain the lenses of clay that would be expected in a classical fluvial deposition mechanisms.
"Carolina bays" are not existent only on flat landscapes. The Goldsboro Ridge Structure includes several clearly delineated Carolina bays within the ridge itself.
(1) A RE-EVALUATION OF THE EXTRATERRESTRIAL ORIGIN OF THE CAROLINA BAYS by J. Ronald Eyton & Judith I. Parkhurst
Geological Research by Cintos is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Based on a work at Cintos.org.
Permissions beyond the scope of this license may be available at http://cintos.org/about.html.
