The Sagainaw Impact Manifold

Evaluating The Carolina Bays As Surface Features In A Distal Ejecta Blanket:
Geophysical Flow Analysis Predicts Bay Orientations,
Enables Triangulation To A Causal Impact Site

Abstract:

We present a novel approach to the genesis of the Carolina bays, proposing that those enigmatic landforms are depositional features within a 1 to 10 meter-thick blanket of hydrated ejecta associated with a cosmic impact into the Wisconsinan ice shield during the latter part of the Pleistocene era, ~40,000 years ago. The ellipsoidal bays exhibit an "inferred orientation", facilitating the use of a triangulation network to identify the associated terrestrial impact crater. Attempts by others to triangulate bay orientations to a causal crater may have failed because the ballistic physics and fluid mechanics aspects of an ejecta distribution were not considered. An analytical model was heuristically developed to generate ejecta emplacement orientations that reflect large-scale geophysical flow effects, and its results were compared to empirically measured bay orientations at ~250 Carolina bay "fields" (representing many thousands of bays). Our model's predicted results correlate well with actual bay orientations when an oblique cosmic impact across the Saginaw area of Michigan is considered. The great-circle distances separating the proposed Saginaw impact crater and all identified Carolina bays also correlate well; the bay’s geographic distribution is along an annulus surrounding the proposed crater. These positive correlations suggest that a unique geospatial relationship exists between the proposed impact location and the Carolina bays of North America. To facilitate independent testing of the hypothesis, a web-based version of the model was made publicly available for integration with the Google Earth GIS.



A comprehensive review of the Hypothesis and our Heuristic Argument is discussed in this web site.

Inspiration

The inspiration for our conjecture was an observation in the paper The Goldsboro Ridge, an Enigma, by R. B. Daniels, E. E. Gamble and W.H. Wheeler, 1970:

The Goldsboro ridge is a unique feature on the Sunderland surface and requires special explanation whatever its origin. It must be either an erosional remnant of a once more extensive sediment or a depositional feature. ...The Goldsboro sand overlies the Sunderland Formation conformably. The contact is always abrupt but there is no evidence of deep channeling, basal coarse material, and evidence of weathering at the contact. Even the Carolina Bays do not disturb the underlying Sunderland materials.... The sand in the bay rim is not different from the Goldsboro sand. Therefore, these Carolina Bays are merely surface features associated with the formation of the ridge.


Introduction


In his 1942 scholarly examination of numerous then-current hypotheses for the genesis of Carolina bays, Johnson noted: “No one has yet invented an explanation which will fully account for all the facts observed”. The Carolina bays continue to challenge geological science to this day. Their sheer numbers, distinct oval circumpheral rims, variety of sizes, and common alignments in any one area are enigmatic. Visual photography available since the bays were observed from the air in the early 1930’s tells only a part of the story. Digital elevation maps (DEM) created with today’s Laser Imaging and Range Detection (LiDAR) systems accentuates their already-stunning visual presentation (Figure 1). While some of the bay’s characteristics are seen in sand dunes or wind-oriented paleolakes, such comparisons are unsatisfactory to us.

Researchers generally consider the bays to be formed within or excised from pre-existing strata (Prouty, 1952; Eyton & Parkhurst, 1975]. We propose that the bays are surface imperfections within a blanket of ballistically deposited shattered sedimentary strata (sand), generated at time of emplacement by the energetic deflation of steam inclusions. The authors feel this interpretation explains many of the bays’ physical characteristics, such as companion bays at different elevations, occasionally intersecting or overlaying one another. Also explained is a mechanism to create bays on ridges, the ridges themselves being comprised of ejecta deposition, which is our interpretation of the Goldsboro Ridge in NC [Daniels, R.B., and E.E. Gamble, 1970].

The lack of a correlated impact structure in North America is problematic for any attempt to implicate a cosmic impact in the genesis of the Carolina bays. Our hypothesis holds that the impacting object was a massive low-density hydrated silicate object, likely a cometary body, which impacted the earth on a shallow angle, nearly tangential to the earth’s surface. Remote sensing has show that approximately 5% of all craters are created during such oblique impacts, creating a set of recognizable characteristics: oval shape, butterfly ejecta pattern, “no-fly” ejecta area up field, and “blow-out” rim down field. [Herrick, R.R, 2009; Herrick R.R. and K. Hessen, 2003]. Recent studies suggest that impacts into solid surfaces protected by a layer of low impedance materials generate structures that differ from the classic crater planforms [Schultz, P. H. and A. M. Stickle, 2009]. In our specific case, we invoke the Wisconsinan ice shield as a low-impedance layer protecting the sedimentary strata of the Michigan basin.

An ejecta curtain wall radiating outward from a cosmic impact should follow a few simple laws of large-scale geophysical flows. We diuscuss our analytical model engineered to replicate those flows in the Analytical Modeling section.

This web presentation is composed of sections discussing:


ButterflyPortrait
Graphic shows the impact site and triangulation from ~200 bay "fields".


googleearth
The Google Earth GIS facility has been heavily leveraged in developing the proposed solution. Images derived from Google Earth are presented under the Google Permissions
Guidelines for Fair Use.
This window offers a view of our Carolina bay field index and the Saginaw Impact in Google Earth's 3-D Browser.


Our efforts in researching the Saginaw Impact Manifold and in presenting our results on the web are entirely self-funded by us. Your donation will assist us in ongoing efforts to determine the true genesis of the Carolina bay.



Carl Sagan noted “The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what's true.... Cleverly designed experiments are the key” (Sagan, 1995). We present our Bearing Calcualtor as a very cleverly designed experiment.

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