Origin Stories

How Carolina Bays Came to Be

Carolina Bays formed at different times, with sediments aged from a few thousand to tens of thousands of years ago, with the oldest just over 100,000 years ago1.  The bulk of evidence indicates that most bays predate the Holocene (~11,700 years ago), the time of the last glacial maximum. Some geologists interpret these data to suggest that bays have been formed periodically over tens of thousands of years, while others hypothesize a single origin >100,000 years ago and subsequent modification and alteration of those bays over time.2

Over the years, there have been many possible explanations proposed for the formation of the Carolina Bays, including spring basins, enclosed soundlets, groundwater solution depressions, artesian springs, wallows from large animals, streamlined groundwater forming limestone sinks, deflation hollows, intersecting river terraces, burning peat leading to subsidence, wind modified and ponded frozen ground, hydrogen seepage, meteorite or comet impacts, and shockwaves from a comet explosion.

While there is not complete scientific consensus, the majority of the evidence suggests formation from directional wind and wave action in relic thermokarst lakes.3

Directional winds and waves

In areas where the ground freezes, repeated freezing and thawing along with directional winds create depressions in the landscape with similar shapes.  Thermokarst lakes can be seen today in the arctic, and geologists theorize that the Carolina Bays formed with similar processes during the last glacial period when what is now the southeastern US was much colder and drier.4 These depressions can be further modified by wind and water to create features such as sand rims.  

Photo: Thermokarst Lakes, Hudson Bay, Canada. Photo: Steve Jurvetson

Geologist have found that the orientations of the Carolina Bays are consistent with the wind patterns that existed during the Wisconsin glaciation (15,000 – 80,000 years before present), as reconstructed from the orientations of parabolic dunes in river valleys.5  Explains shape, orientation, and different ages of sediments.

Boring

Meteor or comet impact

The meteor or comet impact theory has been proposed as early as the 1930’s6, and a University of North Carolina geologist named William Prouty championed the theory in the 1950’s,7 and others have built on it.8 The leading theory is that a meteor or comet impacted glaciers near the Great Lakes region and chunks of ice were thrown up in the air, landing across the east coast creating the elliptical depressions and pushing up sand rims on the far edge.9

Photo: Comet Impact Illustration by Nicole Rager-Fuller, US National Science Foundation

Explains common orientation and shape.  The orientation of the long axis of bays changes with change in latitude, pointing back towards the Great Lakes10.  Overlapping bays could be multiple ice chunks hitting staggered close together.  Prouty conducted lab experiments simulating an impact and produced depressions similar to Carolina Bays.  

No meteor or comet material has been found in bays.11  Wide-ranging soil ages suggest bays were created periodically across tens of thousands of years, not all at once.  

Burning Peat

A study of Lake Mattamuskeet in Hyde Co, NC revealed evidence in the sediments that a large peat fire during a dry period created the large depression, and subsequent water and wind shaped the basin and rim.12

Photo: Peat Fire Evans Road, NC, NC Forest Service

Clear evidence of charcoal in Mattamuskeet sediments.  Large-scale modern day peat fires have created open water lakes. 

While some consider Lake Mattamuskeet a Carolina Bay, it does not have the classic shape and orientation.  Extensive peat deposits do not occur in all areas with bays (e.g. the areas with clay-based bays).

Dinosaur, Giant Beaver, or Whale Wallows

Photo: Brontosauri Wallow in Wetland. From a Disney Postcard.

Would be awesome13

Probably not

Literature Cited

  1. Bliley, D. J.; Burney, D. A. (1988). “Late Pleistocene climatic factors in the genesis of a Carolina Bay”. Southeastern Geology. 29 (2): 83–101.
    Brooks, M. J. (2001). “Pleistocene encroachment of the Wateree River sand sheet into Big Bay on the Middle Coastal Plain of South Carolina”. Southeastern Geology. 40: 241–257.
    Brooks, Mark J.; Taylor, Barbara E.; Grant, John A. (1996). “Carolina Bay geoarchaeology and Holocene landscape evolution on the Upper Coastal Plain of South Carolina”. Geoarchaeology. 11 (6): 481–504.
    Brooks, Mark J.; Taylor, Barbara E.; Ivester, Andrew H. (2010). “Carolina Bays: Time Capsules of Culture and Climate Change”. Southeastern Archaeology. 29: 146–163.
    Grant, John A.; Brooks, Mark J.; Taylor, Barbara E. (1998). “New constraints on the evolution of Carolina Bays from ground-penetrating radar”. Geomorphology. 22 (3–4): 325–345.
    Ivester, Andrew H.; Leigh, David S.; Godfrey-Smith, D. I. (2001). “Chronology of Inland Eolian Dunes on the Coastal Plain of Georgia, USA”. Quaternary Research. 55 (3): 293–302.
    Moore CR (2016). “The Quaternary evolution of Herndon Bay, a Carolina Bay on the Coastal Plain of North Carolina (USA): implications for paleoclimate and oriented lake genesis”. Southeastern Geology. 51: 145–171.
    Moore CR (2012). “Radiocarbon and luminescence dating at Flamingo Bay (38AK469): implications for site formation processes and artifact burial at a Carolina Bay”. Legacy. 16 (1): 16–21. ↩︎
  2. Brooks, M. J. (2001). “Pleistocene encroachment of the Wateree River sand sheet into Big Bay on the Middle Coastal Plain of South Carolina”. Southeastern Geology. 40: 241–257.
    Brooks, Mark J.; Taylor, Barbara E.; Grant, John A. (1996). “Carolina Bay geoarchaeology and Holocene landscape evolution on the Upper Coastal Plain of South Carolina”. Geoarchaeology. 11 (6): 481–504.
    Grant, John A.; Brooks, Mark J.; Taylor, Barbara E. (1998). “New constraints on the evolution of Carolina Bays from ground-penetrating radar”. Geomorphology. 22 (3–4): 325–345.  ↩︎
  3. Swezey, C. S. (2020). “Quaternary eolian dunes and sand sheets in inland locations of the Atlantic Coastal Plain Province”. In Lancaster, N.; Hesp, P. (eds.). Inland Dunes of North America. Dunes of the World. Springer Publishing. pp. 11–63.  ↩︎
  4. May, J. H.; Warne, A. G. (1999). “Hydrogeologic and Geochemical Factors Required for the Development of Carolina Bays Along the Atlantic and Gulf of Mexico Coastal Plain, USA”. Environmental & Engineering Geoscience. 5 (3): 261–270. ↩︎
  5. Carver, Robert E.; Brook, George A. (1989). “Late pleistocene paleowind directions, Atlantic Coastal Plain, U.S.A”. Palaeogeography, Palaeoclimatology, Palaeoecology. 74 (3–4): 205–216.
    Markewich, H. W., and W. Markewich (1994) An overview of Pleistocene and Holocene inland dunes in Georgia and the Carolinas; morphology, distribution, age, and paleoclimate. Bulletin no. 206, United States Geological Survey, Reston, Virginia. ↩︎
  6. Melton, F. A.; Schriever, William (1933). “The Carolina ‘Bays’: Are They Meteorite Scars?”. The Journal of Geology. 41 (1): 52–66.  ↩︎
  7. Prouty, W. F. (1952). “Carolina Bays and Their Origin”. Geological Society of America Bulletin. 63 (2): 167. ↩︎
  8. Lundine, M.; Trembani, A. (2025). “Investigating the origin and dynamics of Carolina Bays”. Marine Geology. 480. ↩︎
  9. Zamora, A. (2017). “A model for the geomorphology of the Carolina Bays”. Geomorphology. 282 (2017): 209-216. ↩︎
  10. Kaczorowski, R. T. (1977) The Carolina Bays: a Comparison with Modern Oriented Lakes Technical Report no. 13-CRD, Coastal research Division, Department of Geology, University of South Carolina, Columbia.
    Johnson, D. W. (1942). The Origin of the Carolina Bays. New York: Columbia University Press. ↩︎
  11. Holliday, V.T.; Daulton, T.L.; Bartlein, P.J.; Boslough, M.B.; Breslawski, R.P.; Fisher, A.E.; Jorgeson, I.A.; Scott, A.C.; Koeberl, C.; Marlon, J.; Severinghaus, J.; Petaev, M.I.; Claeys, P. (2023). “Comprehensive refutation of the Younger Dryas Impact Hypothesis (YDIH)”. Earth-Science Reviews. 247. ↩︎
  12. Rodriguez, Antonio B.; Waters, Matthew N.; Piehler, Michael F. (2012). “Burning peat and reworking loess contribute to the formation and evolution of a large Carolina-bay basin”. Quaternary Research. 77 (1): 171–181. ↩︎
  13. Marcus, Jeffrey F.  2026.  Personal Communication. ↩︎

Banner Photo: Big Cypress Meadow, Leslie Starke

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