Mid Pleistocene Transition
Our working hypothesis holds that the bays were created as voids in sheets of comminuted terrestrial strata spread as a fluidized geophysical mass flow from a well provenanced cosmic impact at 785 ka ±5 k. This was during the Mid Pleistocene Transition (MPT), so named because a significant number of enigmatic events occurred in that era, such as the M-B geomagnetic reversal, and the transition into 100 ky glacial cycles [10] [11]. Evidence is mounting that there was an anomalous “regolith injection” across the continent at ~800 ka, as seen in glacial tills [12] and karst system deposits [13]. If there is any merit to our hypothesis, more 800 ka dates will appear.

Our proposed MPT date has elicited suggestions that Carolina bays do not exhibit a “great age”, as they are “too perfect” in planform. Research into their geomorphology has historically been directed at easily recognized, hydraulically closed examples, but a holistic assessment of the LiDAR shows that erosional and accretionary processes are working to remove the bays
[14].

Thom considered that Carolina bays were formed during the mid to late Pleistocene
[15]. Recent discussions that the bays are associated with the proposed Younger Dryas Boundary (YDB) impact are easily falsified by extensive temporal data - they are far, far older.

In 1943, B. W Wells reported on Blythe Bay in Wilmington, NC [7]. As reported by Savage:

Wells was quite emphatic that he read a catastrophic genesis for the bays. The referenced paper discusses at length how he felt the majority of bays never hosted bodies of water, but simply grew peat deposits many feet in depth on their moist bottoms. Note that peat bogs do not form in open water. His interpretation of the bay lakes which are in existence today is because that, for a very few, they lie low between major rivers and are controlled by water table levels, while many of the bays with water exist because peat within bays had been burned out in the dry periods of the middle Holocene, based on significant findings of charcoal. [16]

Pollen studies [17] record multiple glacial cycles, and 14C dating had long ago evaluated the age of organic deposits in cored Carolina bay basins to be older than 50 ka. The age of bays based on their existence on Cape Fear River terraces sets a minimum date for bay formation at prior to the Illinoian glaciation [18]. Ivester has found bays older than 100 ka using OSL [19].

The Survey’s LiDAR digital elevation maps elucidate bays succumbing to erosion during the dissection of coastal terraces of Cenozoic and Mesozoic age, yet leaving intriguing imprints in Cretaceous terrace remnants at elevations over 200 masl
[8]. Carolina bays in lowlands may have been inundated by fluvial and estuarine deposits, only to delicately project their competent rims to the surface when they are unroofed by erosion, or when buried organics in their basins compact and dissolve away. Sheets of dune sands and aeolian loess have overridden and blanketed clusters of bays, yet they continue to offer evidence of their presence. Such findings suggest that once created, a Carolina bay’s ovoid shape and orientation is deeply imprinted into the landscape, revealing its presence despite the reworking of surficial deposits, likely due to the differential robustness of the high-energy emplacement of the rim constituents. Exploring the various temporal aspects of such alterations may provide constraints on the timing of bay creation.

Any attempt at dating the age of the bays to the MPT will require performing an extensive suite of cosmic isotopic dating technologies to the bay deposits and underlying strata to elucidate the arrival time of the formative rim. When attempting to date bay creation episodes, workers must discriminate between foundational rim deposits and those of subsequent gradualistic processes.


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