Lidar reveals the ancient landforms that most Carolina Bays researchers won't show you

Nearly all online material regarding Carolina Bays focuses on clusters of impressively elliptical bays along the Lumber and Cape Fear Rivers in North Carolina. The expanses of ancient sand dunes that interact with the bays receive comparatively little attention, but they deserve more! The Atlantic Coastal Plain landscape is covered in Pleistocene sand dunes, some of which formed from the edges of the bays themselves, indicating the bays existed during the Pleistocene. Things get interesting when bays cut off each other's sand sheets, suggesting some bays are younger than others. Was bay formation an ongoing process related to climatic conditions and an open, windy landscape? Check out these images and see what you think.

[@MichaelHolloway]

Lidar changes everything. I look forward to more of these.

[@TheGeoModels]

It certainly does.

[@MichaelDavias]

Your initial suggestion that perhaps the migrating dunes could not move into the basin because it’s closed hydrology enables it to be water filled (at least periodically) and circulating water spread the slow dune influx across the entire basin. One test would be to identify basins that are NOT hydraulically close - like those pirated by nearby streams/rivers. I find such basins often breached by normal dune migration.

[@TheGeoModels]

This is a valuable perspective! I admit I am flattered that you watched the video!

[@MichaelDavias]

@@TheGeoModels I approach all this modestly and I am always looking to learn.. Still so much to understand, and my proposal requires that a large swath North America was effectively sterilized 788,000 years ago during MIS 20 ago... but it was probably pretty desolate anyway at that point. We have come to openly expect that North America East of the Rockies needed repopulation in the past, as the ice ages since 2.5 million year ago have been quite persistent. I explains a lot of this, like where the sand came from in the Nebraska Sand Hills (Muhs now states it was NOT from the White River Mountains). But it also creates new challenges.

[@tegtime]

@@MichaelDavias Why would it have been 'pretty desolate'? I doubt there is any evidence for that claim. There are multiple studies that indicate regions

[@justmenotyou3151]

You talk about the sandune sheet froming from the bay and the smaller bay forming later cutting the the sandune. How about the sandune was there before the impact, and both impacts are on top of or obliterated the sandune feture.

[@AustinKoleCarlisle]

this makes the most sense. all of these bays formed at the same time.

[@gravitonthongs1363]

When you find a pristine bay over the top off a heavily eroded bay it is clear verification for the several dating methods which agree these features were formed over a long period …not simultaneously like pseudoscience conspiracy proponents would have you believe.

[@doomoo5365]

Probably for decades and decades after a supposed impact event there wasn't much vegetation between the bays and Sand Dunes did form

[@AustinKoleCarlisle]

@@doomoo5365 EXACTLY! the impacts obliterated all vegetation and this explains the "paleo winds" that created dunes during this time.

[@gravitonthongs1363]

@@doomoo5365 even though we already know there was little vegetation during glacial periods? This is not evidence supporting impact fantasy.

[@anthonywirth3332]

Great video 👍

[@TheGeoModels]

it's an interesting topic!

[@anthonywirth3332]

@@TheGeoModels do you have any good lidar content for the finger lakes?

[@TheGeoModels]

@@anthonywirth3332 I don't, but I bet there's some cool stuff there! I'm mostly a non-glaciated landscape type of guy. Trying to do one more bay thing tomorrow. It shows my favorite bays in South Carolina, which I think are really unexpected in the landscape

[@anthonywirth3332]

@@TheGeoModels looking forward to it

[@namzarf]

Vegetation often presents a very effective barrier to wind and erosion. Vegetation around the raised rims of the bays would present significant resistance to the advancement of wind-b;lown sand, In effect, the sand would collect around the windward edges of the rims as we see in the LIDAR images you've offered.

[@doomoo5365]

If there is a devastated landscape because of ice Boulders smashing into the ground and there would be a period of sand dunes because the vegetation would have been wiped out

[@tegtime]

​@@doomoo5365 ... sure. But it is more likely that the depressions were playa lakes which would have provided bare sediment to form the dunes. As the video showed, there are areas where this phenomena is observed today. The ice impact hypothesis is wildly fanciful.

[@justmenotyou3151]

Nope. These formed from secondary impacts of ice. Carolina bays and Nebraska rainwater basins formed that way.

[@TheGeoModels]

I have heard this theory...

[@justmenotyou3151]

@TheGeoModels it's a good theory, one that needs to be properly evaluated and not dismissed. Zamora work looks detailed and well presented. The counter Arguments used against the theory, zamora does a good job countering them.

[@gravitonthongs1363]

@@justmenotyou3151Zamora’s hypothesis fails scientific scrutiny. It requires the largest impact in billions of years. No geologist supports it.

[@AustinKoleCarlisle]

@@gravitonthongs1363 disinformation.

[@risunokairu]

@@gravitonthongs1363yeah they also denied a asteroid impact wiping out dinosaurs. Science advances one funeral at a time. There is no guarantee that a fractured comet impacting on miles of ice would leave a crater in Canada if the comet was small enough to not reset the planet. It would also flush itself away.

[@testbenchdude]

WTH are you doing, applying facts and reason and logic to this phenomena??? Are you a MADMAN? Oh, the conspiracy theorists are not going to like this one bit. I am especially looking forward to you trying to explain Marine Isotope Stages to both seasoned "scientists" and the general public. You are a brave person for tackling this particular geomorphology, in this space no less, for sure. There's a reason why Geologyhub won't touch it. Anyway, this was very well presented. Subbed!

[@liammerrick6399]

The bays collars are overlapping, overturned sediment. Is that not all the proof we need that they were formed from impact debrit? How does wind form that feature?

[@herbertfawcett7213]

What creates the bays?

[@TheGeoModels]

Pleistocene climate...freeze-thaw, deflation hollows from strong wind on a more treeless landscape, maybe? Depressions become water filled and wind/wave action shapes the boundaries. Wind action moving ice around might contribute; this is seen in modern high latitude oriented lakes.

[@villedocvalle]

@@TheGeoModelsswamp gas

[@AustinKoleCarlisle]

these features were formed concurrently.

[@TheGeoModels]

Have to agree to disagree on that one!

[@AustinKoleCarlisle]

@@TheGeoModels the ice boulder bombardment would've lasted about 10 minutes and would explain why some bays are emplaced overtop of wind-blown ejecta.

[@TheGeoModels]

@@AustinKoleCarlisle Zamora says they are splash chevrons! Plus wrong wind direction and not enough time for miles of dune progradation.

[@TheGeoModels]

Is the wind/impact theory the result of Coriolis deflection of syn-impact updraft inflow? Seems unlikely that could be instantaneous thing. Wind definitely from southwest in southeast US at time of bay development, which doesn't line up with northern tier impact...

[@AustinKoleCarlisle]

@@TheGeoModels Zamora posits that the atmosphere would've been ripped open when the comet struck and there would have been a rush of surface-level wind to replace it. if the comet came from the west and imparted that momentum into the atmosphere, it could explain why there is west-to-east wind damage. there is also other damage I've found on Lidar that seems like it would date this wind event. perhaps you'd like me to send it to you?

[@anthonywirth3332]

I just wonder if flooding was accuring or accured shortly after some of the inpacks, then higher acr of the ejecta? Dunes being water born rather than wind?

[@TheGeoModels]

Not sure about water producing parabolic dunes...probably worth a read-up. I gave it a quick look but didn't find any direct discussions

[@anthonywirth3332]

@@TheGeoModels that's a good point, typically you get ripples. Like those huge examples out west, in the scab lands.

[@TheGeoModels]

@@anthonywirth3332 check out the modern-day parabolics in this post, compared to some Pleistocene lidar dunes in Georgia bay country: princegeology.com/pleistocene-coastal-plain-sand-dunes-and-the-value-of-pattern-recognition-in-lidar-interpretation/

[@anthonywirth3332]

@@TheGeoModels wow, great article, the example of the Alaskan landscape being compared to the them.

[@TheGeoModels]

@@anthonywirth3332 yeah I thought those Alaskan dunes were cool. You got to get somewhere windy and pretty treeless and covered with unconsolidated sediment to see stuff today like the Pleistocene features in lidar.

[@stephenmesser4196]

Thank you so much for this explanation , I first heard about Carolina bays in an article about Bon Air near Richmond VA being a Carolina Bay.

[@TheGeoModels]

They're quite widespread, but definitely just hide out without lidar. I presume some of them in Coastal Plain Virginia were still little lakes when folks were making arrowheads at Cactus Hill!

[@AustinKoleCarlisle]

@@TheGeoModels Hey man, can I send you those coordinates about the "paleo" wind damage I've observed in LiDAR? I think it can conclusively date the catastrophic wind event.

[@TheGeoModels]

@@AustinKoleCarlisle yes friend I apologize for my slow reply! Landslide work has been dominating recently! Go to Princegeology.com and find the email in the contact and send em my way. May take me a few days though; got to some travel work next week!

[@AustinKoleCarlisle]

@@TheGeoModels thanks, man. i am really curious to hear your professional input on the evidence i've found, and all i ask is that you look at it with an open mind. i'll shoot you an email tonight.

[@TheGeoModels]

@@AustinKoleCarlisle got it, and will do! Still give me a bit here to put these other fires out, but we are in contact now and good to go!

[@AustinKoleCarlisle]

i was thinking about how to conclusively date the formation of the bays, and aside from inverted rim stratigraphy (which might be a hit-or-miss finding), i think the next best way to verify the age of a bay is to OSL test sand grains near the bottom of a dune that has encroached a Carolina Bay. if Zamora is correct, there shouldn't be any dates older than 12,900 years. but if Carolina Bays are hundreds of 1000s of years old, we should expect to find dates well beyond the YD boundary.

[@TheGeoModels]

be back with yall soon

[@AustinKoleCarlisle]

@@TheGeoModels no worries!

[@user-ix7bm6jx1c]

Big Bay in Sumter County, South Carolina, is a Carolina Bay into which eolian dunes have migrated (eolian dunes overlie the western part of the Carolina Bay). These eolian dunes that overlie the western part of this Carolina Bay have yielded luminescence ages ranging from ~74,300 to 29,600 years (see Swezey, 2020, p. 38; and references cited therein).

[@AustinKoleCarlisle]

@@user-ix7bm6jx1c yes, i was talking to zamora about this particular bay, and he believes during the ice boulder bombardment that a giant tidal wave of mud washed over the landscape and this was responsible for most of the mass of the dune. i'm curious to know the particle sizes located in those dunes. if the particles were too large to be carried by the wind, then that would support antonio's theory. i'm also curious to know if the soil is stratified and if the OSL age correlates with sample depth, does he say specifically at what depth the dates were obtained and how many samples were taken?

[@user-ix7bm6jx1c]

@@AustinKoleCarlisle The low-relief hills that overlie the western side of Big Bay near the confluence of the Wateree River and the Congaree River are composed primarily of fine to medium sand (most grain size diameters range from 0.13 mm to 0.50 mm). I have been to this location and observed the sand sizes myself. There is really no mud here. Stratification is not visible in shallow pits dug into the sand, but that is consistent with many (most) other vegetated dune fields in river valleys of the Atlantic Coastal Plain. It would have been no problem for winter winds to move these grain sizes during the last glaciation or previous glaciations (with colder air temperatures, a given wind velocity can move larger grain sizes). Ivester et al. (2002) and Brooks et al. (2010) have reported three published luminescence ages from these sands. Each of these three ages is from a sample collected at a different location, although the authors do not specify the depth below the surface at which the samples were collected. The first sample (Wateree 01) was collected at 33.7900 latitude/-80.4852 longitude, and yielded an age of 74.3 +/- 7.1 thousand years (in other words, 81.4-67.2 thousand years). The second sample (Wateree 02) was collected at 33.7866 latitude/-80.4891 longitude, and yielded an age of 29.6 +/- 2.4 thousand years (in other words, 32.0-27.2 thousand years). The third sample (Wateree 03) was collected at 33.8008 latitude/-80.4989 longitude, and yielded an age of 33.2 +/- 2.8 thousand years (in other words, 36.0-30.4 thousand years).

[@jollyroger7624]

Not necessarily so. So many theories, but only one is right, Any theory concerning the bays is just that, a theory, unless it explains exactly how the bays themselves were formed. Talk of windblown sand is just a distraction until it's decided how the bays formed. Investigating the layering of the windblown sand comes way before deciding the timing of bays and chevrons. Has that been done? As for bays being formed at different rates or times is very clearly spurious. Nowhere in the world can this bay formation be seen to be active today. We should not be ignoring overturned layers at the southern end of the bays, as there would be with impacts. The physics of so many impacts over such a widespread countryside in such a short time period is mind boggling. Can anyone with any competence say what effect winds of many hundreds or thousands of miles per hour would do when combined with billions of tons of water travelling at supersonic speeds? It's just another distraction comparing present day windblown sand forms with those of the bays, clearly no present wind formations are anywhere near the scale of the bays. Once science gets it's act together it will prove the one event was responsible, for not just the bays, but will also explain the extinctions of so many peoples and beasts.

[@AustinKoleCarlisle]

science progresses one funeral at a time! give it a few years and we'll be told "we knew all along it was the Younger Dryas Cataclysm that caused the Carolina Bays".

[@gravitonthongs1363]

The Carolina bays are far more widespread than any boulders from Chicxulub. Formation by impact ejecta requires the largest impact in billions of years.

[@AustinKoleCarlisle]

@@gravitonthongs1363 look up articles about Corinto crater on Mars that created 2 billion secondary craters from ejecta that traveled up to 2000 kms. so much for your claim that ejecta can only travel 5x the diameter of the impactor.

[@gravitonthongs1363]

@@AustinKoleCarlislelol to you not understanding that mars has a thin atmosphere and less mass than the Earth (where ejecta blanket law is derived and applied)

[@AustinKoleCarlisle]

@@gravitonthongs1363 and you should be aware that those ejecta blanket laws are specifically referring to METEOR strikes onto TERRESTRIAL soil. this scenario involves icy comet onto glacial ice, not even comparable.

[@SJR_Media_Group]

The round formations are NOT Bays.... which are ALWAYS Elliptical and ALWAYS have their long axis point towards the Great Lakes regardless which State they formed in.

[@TheGeoModels]

Interesting interpretation! Thanks for watching!

[@tegtime]

you're right! they are not bays but are playa lakes. It is a not coincidence that they point to the Great Lakes, too. The shape of the lakes is due to wind drawing out the shape since it there were intervals over the last 30,000 where surficial winds were shockingly constant - generally from the NW.

[@SJR_Media_Group]

Thanks for commet

[@st-ex8506]

@@tegtimethere is not a chance in a zillion that wind formed Carolina bays. The prevailing wind was possibly from the NW in the Carolinas, but was it from the north in Texas? From the ENE in Iowa? Or from the WNW in Long Island? Also, wind never creates perfect elliptical shapes, but rather pear-shaped ones. Finally, the wind does not upturn and inverse the sedimentation layers of the rims.

[@AustinKoleCarlisle]

@@tegtime how do you explain the bays that do not orient to the Great Lakes? it not an insignificant number.

[@AustinKoleCarlisle]

experiments involving the wind & water hypothesis never replicated elliptical geometry, nor was the 1977 paper by Kaczorowski ever peer-reviewed. in other words, the eolian hypothesis for Carolina bay formation is complete speculation, and any dates obtained using this hypothesis cannot tell us when an impact occurred because the perfectly elliptical and consistent geometry of the bays indicates an impact origin--not primary impacts, but secondary impacts. please refer to Zamora's work for more information. thank you.

[@user-ix7bm6jx1c]

In Google Earth, please look at Barrow, Alaska. Also look at the Falkland Islands. These features are thermokarst lakes. Also, please note that in the eastern United States, many Carolina Bays have a nice elliptical geometries and consistent orientations in North Carolina and South Carolina, but geometries and orientations are less consistent farther north and south (e.g., New Jersey, Georgia).

[@AustinKoleCarlisle]

@@user-ix7bm6jx1c the nice elliptical geometries of the Carolina Bays in the SE are a direct result of the deep sandy soil, high water table, and extremely flat terrain in that region. whereas the soil from the Mid-atlantic northward isn't nearly as deep, the water table isn't as high, and the terrain isn't as flat--all of these variables reduce the probability of creating perfectly elliptical CBs. as for the orientations, that is the result of multiple impacts.

[@user-ix7bm6jx1c]

@@AustinKoleCarlisle In Google Earth, please look at Barrow, Alaska. Also look at the Falkland Islands. These features are thermokarst lakes.

[@AustinKoleCarlisle]

@@user-ix7bm6jx1c thermokarst lakes are not morphologically comparable to the Carolina Bays. why do you push the wind and water hypothesis for Carolina bay formation when experiments have failed to reproduce elliptical geometry and the associated 1977 paper by Kaczorowski was never peer-reviewed? last time i checked, that is not "following the science". we should be following the science, right?

[@gravitonthongs1363]

⁠​⁠@@AustinKoleCarlislethermokarst lakes are far more morphological comparable to the bays than impact craters (which correlate depth to width and have entire rims) Why are you obsessed with pushing pseudoscience in conspiracy form?

[@MorganBrown]

When I saw those potholes, it made me think of the salt karst features that you see in Kansas. Well, on 3D seismic data you can "see" them pretty well!

[@TheGeoModels]

I hear you...the bays do well with GPR study. Would be nice if they were karst to settle all the debates.

[@worldbridger9]

You know, it can be both! after bombardment, there was a hellscape for decades... wind can move ejecta!

[@TheGeoModels]

The Pleistocene was probably a hellscape at most latitudes under the best conditions!

[@greenman6141]

Another totally fascinating video. And anything that speaks sense - sense based on facts - to the current obsession with seeing "impact related features" every where brightens one's day. Though the vogue for impacts under every stone is LESS totally silly than ancient astronauts or Atlantis, they nevertheless look suspiciously like close cousins.

[@TheGeoModels]

Lidar is a game-changing tool, and makes everyone look closer in hopes of supporting their argument. I am sure some useful "collateral discoveries" will come out of the bays debate.

[@AustinKoleCarlisle]

@@TheGeoModels you should adjust your Lidar to where the colors of the rainbow repeat every 10 meters. it's WAY more revealing than the color scheme you have here.

[@TheGeoModels]

@@AustinKoleCarlisle here is the devil's advocate! How much topo relief is there across the typical Carolina Bay?

[@AustinKoleCarlisle]

@@TheGeoModels upwards of 7 meters, but usually around 2-5 meters. do you still want the coordinates of the wind damage I believe can date this event?

[@AustinKoleCarlisle]

@@TheGeoModels do you want those coordinates? i'm highly interested in your geological expertise on the matter.

[@sarahdawn7075]

Supposedly the jet stream was briefly pushed down close to the surface by the expanding vapor plume created when an extra terrestrial object impacted the ice sheet near the great lakes. This is what created the ice boulders that formed the secondary impact craters that we call Carolina Bays. The ice boulders themselves did create splash chevrons as they impacted wet soil liquified by the vibration from the impacts. The sheets of sand along rivers and streams are not "splash" chevrons created by impacts. These sand sheets are more akin to ones left by tsunami waves. They were created by hurricane force winds coming from the south west, blasting across the coastal plains and blowing water and sand out of their river, stream and lake beds. This occured as the jet stream was suddenly displaced to the surface following the impact into the ice sheet. (Note: wind direction is dictated by the flow of the jet stream. It is not a blast wave from the impact.) The rain-down of ice boulders that created all Carolina Bays took only minutes. There are sand sheets that partially cover bays that also have bays on top of the sheet, meaning the sand sheet formed as the ice bombardment was taking place. The video also shows an example of a bay on top of a sand sheet with a splash chevron formed as it landed. The splash chevron points in the same direction as the sand sheet. In the same view you can see other bays to the right that formed and then were partially inundated by the wave that created the sand sheet. That was followed by the impact to the sand sheet that created the bay in the center that has a splash chevron.

[@AustinKoleCarlisle]

This is my interpretation of the landscape features, as well. All the evidence points to a sudden blast of wind from west-to-east at the Earth's surface during this bombardment of ice boulders. I have more evidence of this wind damage for the channel owner to review; I believe it can conclusively date when this wind event took place by geological deduction. @TheGeoModels

[@gravitonthongs1363]

See ejecta blanket law to realise that a minimum 1000km wide crater is required to explain the bays as impact ejecta marks. Zamora’s hypothesis is clear pseudoscience.

[@tegtime]

The jet stream was not briefly pushed down - it was dramatically altered for thousands of years. Specifically between 29,000 to 19,000 thousand years ago. During this interval, the Laurentide Ice Sheet was >8,000 ft thick and would have acted like a mountain range. Unlike the rockies though, the shape of the ice would have been a dome, rather than a series of peaks and valleys. The mass of ice sheet was also always at or below freezing, causing a perminate high pressure system over the ice. Combined, these factors caused the weather patterns to have a constant track. The winds in most of the Midwest and eastern US would have been from the NW. The evidence for this is thick dust deposits and sand dunes all across the country. The dust and sand was sourced from river valleys and the dust is thickest on the southeastern (down wind) side of the valley as are the dunes. The tens of thousands of dunes across the US deposited during this interval have a shape indicating winds from the WNW to NWN. So it wasn't one short event that caused these features, but a significant paleoclimactic interval. The depressions of the Carolina Bays are playa lakes and the dunes blew out of them during intervals when the lakes dried out. This is why there are Carolina Bays with multiple rims on the SE side (the down wind side). The sand bodies cannot be ejecta, because the energy from the impact would have scattered the fine-grained sediment much, much further from impact site. This impact hypothesis has been repeatedly disproven by field-based evidence. The biggest is that the sediment in the basins is not disturbed and has similar layers to the area around the depression. If you would like references to the studies I would be glad to help.

[@AustinKoleCarlisle]

@@tegtime although well spoken and formulated, your conclusion does not account for inverted stratigraphy of the raised rims of Carolina Bays that date-tests to approx 12.8k ybp at the inversion point. this can *only* be explained by an impact. see Bunch, et al

[@gravitonthongs1363]

@@AustinKoleCarlisle impact craters have rim heights corresponding to crater depth. A 3km bay with the same rim height as a neighbouring 50m bay is obvious evidence debunking impactor formation …along with all the other factors such as absence of impactor markers, large range of dating, soft flat terrain selection, large variations in shapes and orientation, etc.

[@jcomstock4246]

Literally everything that you said is supposition

[@TheGeoModels]

Thank you for watching and commenting!

[@pauldickman4379]

If you spend 20 minutes going through lidar data, the impact theory falls away fast. It's next to impossible to share links on here or I would. New Jersey has easy to use lidar though. There are clearly many generations of bays of all shapes and orientations. Wind just makes so much more sense...

[@TheGeoModels]

Do you just run it through National Map? The bay landscape down on the Delmarva is very impressive. I probly should have just done the dune/bay orientation thing, but whatever. Might do it later. The dunes in south Georgia are quite beautiful (at least in a stretched hillshade!).

[@pauldickman4379]

@@TheGeoModels I can't seem to find a lidar map for the entire area or nation I just search state by state. Searching just through New Jerseys had multiple locations where the bays are overlapping in every orientation you can imagine from NS to EW everywhere in between, all in the same few square miles. Was enough for me to personally dismiss the impact theory until someone can actual find some good solid evidence for it.

[@TheGeoModels]

@@pauldickman4379 I fear there won't be solid impact evidence... I'll do a National Map video. You can stream lidar from most states, though resolution does vary somewhat. It works about the same as ArcGIS online web viewers, and the stretched hillshade function is good for coastal plain stuff.

[@AustinKoleCarlisle]

@@pauldickman4379 Carolina Bay Survey website has way better resolution than what is used on this channel

[@tegtime]

@@pauldickman4379The field-based evidence confirms that these depressions are not impact craters. It's pretty funny that people see dunes on the edge of playa lakes and mistake them craters. The depressions are only a few meters below the surrounding landscape and the sediment in them has the same horizons and beds. People just get too hung up on the orientation :(

[@markalan1501]

Nope...it's from the last pole shift.

[@TheGeoModels]

Now that is interesting!

[@edwardhill3676]

They are impact craters from very large chunks of ice.

[@gravitonthongs1363]

…said no scientist ever

[@doomoo5365]

​@@gravitonthongs1363Antonio Zamora uses mathematics and geology to explain it, he's a geologist

[@gravitonthongs1363]

@@doomoo5365 Zamora is a computer technician you fool. The mathematics of ejecta blanket law is far from compatible with his fantasy

[@AustinKoleCarlisle]

@@gravitonthongs1363 that law was based on meteor strikes onto terrestrial soil.

[@gravitonthongs1363]

@@AustinKoleCarlisle again… it encompasses all known impacts on earth including many type of terrain, and water. Ignorance of evidence to suit your ideology is pseudoscience.

[@Texan190]

Good theory, but how does this explain the ones found further to the west in iowa, kansas, nebraska, even TX?

[@TheGeoModels]

They line up at the same angle to the dune systems out there. The dune-forming winds were more north-south, making the elliptical depressions trends more east-west (they are slightly northeast-southwest). In any case, the general wind-sculpting idea fits with the dune fields and depression orientation, which is quite different from what is seen on the east coast.

[@Texan190]

@@TheGeoModels I'm sorry, I don't follow with that. How to North -South winds form east-west structures? Are you hypothesizing that these depressions are formed by aeolian processes, elongated? The Laurentide ice sheet had a maximum that only went so far south, not really going beyond Illinois, Indiana, and Ohio. It fluctuated of course over thousands of years, but didn't come further south. Were winds really strong enough from that distance, traveling over the Appalachians to get to the coast and create these elongated structures? Also traveling to the locations in Kansas, Nebraska, Oklahoma, even TX?

[@Texan190]

@@TheGeoModels There's this to consider too. I wondered how far below permafrost would be based on the last glacial maximum. Certainly it didn't make it down to Georgia or even Texas. What are your thoughts? kzbin.info/www/bejne/lYHbYqCOgbmti6csi=JUweLpFcawfmiy40

[@TheGeoModels]

@@Texan190 so the relationship between wind direction/dune orientation and bay long axes is definitely there. Because the sediment in the bottoms of the bays indicate that they were water-filled depressions at some point, by comparison to modern oriented lakes they would have elongated nearly perpendicular to wind direction. This occurs because wind over the lakes causes wave and water movement which focuses energy on the ends of the water-filled depression. You can look up oriented lakes and it will be diagrammed. So yes, wind will causes small lakes in unconsolidated sediment to elongate nearly perpendicular to wind direction--it's seen in many places on earth today. This process fits with the dune orientations, the bay orientations, and the little dunes that come off the bays. It also fits with the dune orientations in the midwest relative to the southeast, where wind patterns would have been different in the Pleisto as they are today. It's definitely worth a cruise on national map and google earth! Thanks for watching and commenting!

[@tegtime]

@Geomodels is correct about the process for elongating the lakes. The Carolina Bays are playa lakes, which are common in areas flat areas that lack streams and rivers. These can be found in Nebraska, Kansas, and Texas. These typically form in areas that may be more monsoonal, having a strong break between rainy and dry seasons. When it does rain, the water ponds on the surface in low areas and can kill vegitation not adaptaed to being submerged. These waterbodies eventually form depressions due to wave action from wind shaping the bottom. When the lakes dry, vegitation adaptaed to being submerged dies off. The now bare sediment in the bottom is perfect for wind to erode. Fine grained silts and clay become dust and is blown away while coarser sand is blown to the downwind side of the lake. The next rainfall carries in sediment as it wash in, refreshing the bottom of the lake. This cycle can be an annual event or occur ever few years, but it took place for thousands to tens of thousands of years in some areas. If the wind is from generally consistent direction, the basins will show this preference. The circular depressions in Iowa are varied and range from ice walled lake plains, pingo scars, and other glacial and periglacial features. There was already ice covering parts of the state while permafrost was found in the rest, so that is much more plausable than the depressions being impacts.