Reader thinks Carolina Bays have glacial origin

Hello Robert,

Here is my explanation for why the Carolina bays are oval and oriented all in the same general direction, and why I think they have a glacial origin:


Carolina Bays - Lidar image

Glacial Kettles are formed by large blocks of relatively sediment-free(clearer) ice being carried along in an ice-mass that is more uniformly sediment laden (gravels, glacial till). When the ice-mass finally melts, it does not always melt at once, nor at the same rate. The motion of the whole ice-mass accounts for the oval shape of the bays. In areas where kettle lakes are more round than oval, one can assume that the containing ice-mass was in relative stasis, i.e.: not in motion when melting occurred.

I searched on ‘Carolina Bays Topography’ and found:

PART II; Guidebook To The Geology of Upland Gravels near Midlothian, Virgina by Bruce K. Goodwin and Gerald H. Johnson, Department of Geology, The College of William and Mary, Williamsburg, Virginia

“Upland surfaces covered by gravels are relatively flat and undissected”.
http://abob.libs.uga.edu/bobk/cbayvirg.html

and later in the same article:

“A reconnaissance survey of the surrounding region revealed that these basins(bays) are restricted to the upland surfaces of the Midlothian gravels. No evidence was found of similar basins in Piedmont areas without a gravel veneer or in areas which have been severely dissected by erosion”.

Undissected means not eroded dendritically by rivers and creeks, this suggests to me that these bay features are also typical of glacial outwash plains. Where else could the gravels come from if not deposited by a melting ice mass, or a wide flat glacial outwash river?  (the ancient James River for ex.)

Although the page cited above does not attempt to speculate on the origin of the “bays”, it does say this:

“A summary of the major origins forwarded for Carolina Bay formation include: meteorite impact; solution; submarine scour and subsequent wind action; artesian springs and ground water action; the action of wind and currents on shorelines; rotation of the earth aided by currents and wind; the schooling of fish around fresh-water springs on the continental shelf; and possibly the meandering of streams”.
Some of these can likely be easily ruled out.

Although I still think the bays are formed from one of the ice ages that is very much older than the most recent one which formed the Laurentide ice sheet.

If you publish my comments, please omit my last name.

Thanks, and thank you for your sites!

Andrew S.

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