Posted on 07/24/2006 12:03:03 AM PDT by ForGod'sSake
The Paleoindian occupation of North America, theoretically the point of entry of the first people to the Americas, is traditionally assumed to have occurred within a short time span beginning at about 12,000 yr B.P. This is inconsistent with much older South American dates of around 32,000 yr B.P.1 and the similarity of the Paleoindian toolkit to Mousterian traditions that disappeared about 30,000 years ago.2. A pattern of unusually young radiocarbon dates in the Northeast has been noted by Bonnichsen and Will.3,4
Our research indicates that the entire Great Lakes region (and beyond) was subjected to particle bombardment and a catastrophic nuclear irradiation that produced secondary thermal neutrons from cosmic ray interactions. The neutrons produced unusually large quantities of 239Pu and substantially altered the natural uranium abundance ratios (235U/238U) in artifacts and in other exposed materials including cherts, sediments, and the entire landscape. These neutrons necessarily transmuted residual nitrogen (14N) in the dated charcoals to radiocarbon, thus explaining anomalous dates.
We investigated a cluster of especially young radiocarbon dates concentrated in the north-central area of North America. For example, at the Gainey site in Michigan a 2880 yr B.P. radiocarbon date was reported, while the thermoluminescence date for that site is 12,400 yr B.P.5 Other anomalous dates found at Leavitt in Michigan,6 Zander and Thedford in Ontario,7 Potts in New York,8 Alton in Indiana,9 and Grant Lake in Nunavut10 are summarized in Table 1. The Grant Lake Paleoindian site is most remarkable because its 160 [rc] yr B.P. age is nearly contemporary, while adjacent and deeper samples give ages of 1480-3620 [rc] yr B.P.
Stratigraphic associations place Paleoindian occupations at depth on the prehistoric North American landscape on sediments that form the old C horizon composed of parent material, Wisconsinan deposits that predate Holocene sediment buildup.11,12,13 The young Paleoindian dates cannot be correct, particularly since there are no patterned anomalies noted in later-period prehistoric assemblages relating to higher stratigraphic positions. In a pioneering study of the Paleoindian site at Barnes, Michigan, Wright and Roosa observed that Paleoindian artifacts were deposited before the formation of spodosols ceased in this area about 10,000 yr B.P.14 This conclusion was based on observing that cemented sediments on artifacts, found outside their original context, defines their original stratigraphic position.
Sediment profiles were taken at Paleoindian sites and at numerous widely separated control locations in Michigan. The C sediment horizon is clearly recognized by its transitional color and confirmed by elevated concentrations of potassium and other isotopes. Color and chemistry are key indicators of this very old soil11,12,13,14 derived from parent materials and associated postglacial runoff.15 At Gainey, large quantities of micrometeorite-like particles appear to be concentrated near the boundary between the B and C sediment horizons. They can be separated with a magnet and are identified by the presence of chondrules and by visual evidence of sintering and partial melting. These particles, dissimilar to common magnetites, are found in association with a high frequency of "spherules." The depth profiles for potassium and particles at the Gainey site are compared in Fig. 1. Minor vertical sorting of particles is apparent, with a shallow spike of particles near the surface probably resulting from modern agricultural or industrial activity. Total gamma-ray counting of sediment profiles in the various locations invariably showed increased radioactivity at the B-C boundary consistent with enhanced potassium (40K) and possibly other activities.
Microscopic examination of chert artifacts from several widely separated Paleoindian locations in North America revealed a high density of entrance wounds and particles at depths that are evidence of high-velocity particle bombardment. Chondrules were identified visually; their presence necessarily indicates heating during high-speed entry into the atmosphere. The depth of penetration into the artifacts implies that the particles entered with substantial energy.16 Field simulations with control cherts for large particles (100-200 microns) suggest an entrance velocity greater than 0.4 km/s, and experiments at the National Superconducting Cyclotron Laboratory indicate that the smaller particles left tracks comparable to about 526 MeV iron ions (56Fe) in Gainey artifacts. Similar features are not observed in later-period prehistoric artifacts or in bedrock chert sources. Track angles were estimated visually; track densities were measured with a stage micrometer; track depths were found by adjusting the microscope focus through the track. These data are summarized in Table 1.
Track and particle data in Table 1 suggest that the total track volume (density times depth) is highest at the Michigan, Illinois, and Indiana sites and decreases in all directions from this region, consistent with a widespread catastrophe concentrated over the Great Lakes region. The nearly vertical direction of the tracks left by particle impacts at most sites suggests they came from a distant source.
Natural uranium, which is ubiquitous in cherts, has a 235U/238U isotopic ratio of 0.72 percent, which varies by less than 0.1 percent in natural sources.17 Significant variations in the isotopic ratio do not occur because of chemical processes; however, a thermal neutron bombardment depletes 235U and thus alters the ratio. Solar or galactic cosmic rays interacting with matter produce fast secondary neutrons that become thermalized by scattering from surrounding materials. Thermal neutrons see a target of large cross section (681 barns)A for destroying 235U, compared with a target of only 2.68 barns for neutron capture on 238U. Therefore, despite the low abundance of 235U, about 1.8 times as many 235U atoms are destroyed as 238U atoms by thermal neutrons.
If a large cosmic-ray bombardment impacted the earth and irradiated the prehistoric landscape with thermal neutrons, the 235U/238U ratio would be changed; 239Pu would be produced from neutron capture on 238U, followed by the decay of 239U. Neutrons colliding with nitrogen (1.83 barns) would create 14C in exactly the same way 14C is normally produced in the upper atmosphere, necessarily resetting the radiocarbon dates of any organic materials lying near the surface on the North American prehistoric landscape--including charcoals at Paleoindian sites--to younger values. 239Pu produced during the bombardment will also be partly destroyed by thermal neutrons with 1017 barn cross section. Assuming 239Pu doesn't mobilize, it will decay back to 235U (half-life 24,110 yr), partially restoring the normal abundance.
Paleoindian artifacts from Gainey, Leavitt, and Butler, and two later-period artifacts from the same geographic area of Michigan were analyzed for 235U content by gamma-ray counting at the Phoenix Memorial Laboratory, University of Michigan. They were compared with identical chert types representative of the source materials for the artifacts. Control samples were extracted from the inner core of the purest chert known to be utilized by prehistoric people. The Paleoindian artifacts contained about 78 percent as much 235U as the controls and later-period artifacts, suggesting substantial depletion. Depletion of 235U necessarily indicates that thermal neutrons impacted these artifacts and the surrounding prehistoric landscape.
Various artifacts, cherts, sediments, and a control sample containing about 0.2 percent uranium obtained from uraninite were sent to the McMaster University Centre for Neutron Activation Analysis to determine 235U concentration by delayed neutron counting and 238U concentration by activation analysis. These results are shown in Table 2. The 235U/238U ratios for all samples except the control deviated substantially from the expected ratio. McMaster ran additional calibration standards and has considerable expertise analyzing low-level uranium. This analysis was sensitive to a few ppb for 235U and 0.1-0.3 ppm for 238U, more than sufficient to precisely analyze the uranium-rich chert samples (0.7-163.5 ppm). Most samples were depleted in 235U, depletion increasing geographically from the southwest (Baker, Chuska chert, 17 percent) to the northeast (Upper Mercer, 77 percent), as shown in Table 2. This is consistent with cosmic rays focused towards northern latitudes by Earth's magnetic field. Only a very large thermal neutron flux, greater than 1020 n/cm2, could have depleted 235U at all locations.
Samples of unaltered flakes from Taylor and sediment originally adjacent to Gainey artifacts showed 235U enriched by 30 percent. Both samples were closely associated with the particles described above. The position of these samples appears to be related to the enrichment, which cannot be explained by thermal neutrons from the bombardment. To test this, we bathed another Taylor flake in 48-percent HF at 60°F for ten minutes to remove the outer 70 percent of the sample and the attached particles. Analysis showed the "inner" flake depleted in 235U by 20 percent, consistent with the other depleted cherts.
Samples of Gainey sediment and Taylor flakes were analyzed for plutonium by Nuclear Technology Services, Inc., of Roswell, Georgia, which specializes in radiochemistry using standard methodology. The plutonium, with an aliquot of NIST-traceable 242Pu added, was chemically separated on an anion exchange resin column and counted on an alpha-particle spectrometer. The 239Pu/238U ratios in both samples were approximately 10 ppb, vastly exceeding the expected ratio of 0.003 ppb.18 The results of this analysis are shown in Table 2.
Chert is a glass-like material highly impervious to penetration by any nuclear fallout that might also contribute 239Pu. We analyzed a long-exposed piece of Bayport chert by gamma-ray counting at the LBNL low-background facility for the presence of cesium-137 (137Cs), a key indicator of fallout (from nuclear testing), and found none. The B-C interface typically lies sufficiently deep that contamination by fallout is improbable. It is important to note that fallout cannot explain the depletion of 235U.
Since the depletion of 235U must have resulted from bombardment by thermal neutrons, the presence of 239Pu from irradiation of 238U is expected. The total thermal neutron flux required to produce the observed 239Pu concentration can be calculated from the relative concentrations of 239Pu (corrected for the decay) and 238U, and the thermal neutron-capture cross section for 238U. This neutron flux can then be used to estimate the amount of additional 14C that would have been produced in charcoal by neutrons colliding with 14N (14N cross section = 1.83 barns). The corrected radiocarbon age can then be estimated by comparing the current amount of 14C in the dated charcoals, determined from their measured radiocarbon age, with the amount of 14C that would have been produced by the bombardment. For these calculations we assume that charcoal contains 0.05 percent residual nitrogen19 and that initial 14C concentrations were the same as today (one 14C atom for 1012 12C atoms).
We derive a thermal neutron flux of c. 1017 n/cm2 at Gainey, which corresponds to an approximate date of 39,000 yr B.P. No radiocarbon date is available for the more southerly Taylor site, but for the conventional range of accepted Paleoindian dates the neutron flux would be c. 1016 n/cm2, giving a date of about 40,000 yr B.P. These calculations necessarily neglect differences in the neutron flux experienced by the dated charcoal and the artifacts, the effects of residual 239Pu from previous bombardments, and loss of 239Pu due to leaching from chert over time.
The neutron flux calculated from the 235U/238U ratio is more than 1000 times that implied by the level of 239Pu. Since 239Pu decays to 235U, partly restoring the natural abundance, it appears that substantial quantities of 239Pu have migrated out of the chert. This mobility is demonstrated at the Nevada Test Site, where plutonium, produced in nuclear tests conducted by the U.S. between 1956 and 1992, migrated 1.3 km.20 It has also been shown that atoms produced by radioactive decay or nuclear reaction become weakly bound to the parent material and pass more readily into solution than isotopes not affected.21 Both 239Pu and 235U are thus expected to be mobile, complicating any analysis. This is consistent with the enrichment of 235U in the two external samples where migrating 239Pu or 235U may have been trapped, thus enriching the relatively uranium-poor outer regions. Alternatively, excess 235U may have been carried in by the particles. Radiocarbon produced in situ by irradiation should also be mobile. If 14C is more mobile than 239Pu, then the dates calculated above should be decreased accordingly.
The 39,000 yr B.P. date proposed for the Gainey site is consistent with the prevailing opinion among many archaeologists about when the Americas were populated. It is also commensurate with dates for South American sites and with a Mousterian toolkit tradition that many see as the Paleoindian precursor. The proposed date for the Gainey site also falls closer in line with the radiocarbon date for a Lewisville, Texas, Paleoindian site of 26,610 ± 300 yr B.P.22,23 and radiocarbon dates as early as c. 20,000 yr B.P. for Meadowcroft Rockshelter.24 Since the Lewisville and Meadowcroft sites were likely exposed at the same time to thermal neutrons, we estimate that their dates should be reset to c. 55,000 yr B.P. and c. 45,000 yr B.P., respectively.
It is likely that Paleoindians occupied low latitudes during the full glacial and migrated to more northerly areas as the ice front retreated. Therefore the pattern of dates makes sense from the archaeologist's point of view. Dates for North American sites should generally be reset by up to 40,000 years, depending on latitude and overburden.
Geologists believe that before c. 15,000 yr B.P. the Wisconsinan glaciation covered the more northerly locations where Paleoindian sites have been found.25 The ice sheet would have shielded the landscape and any artifacts from an irradiation. (The Gainey thermoluminescence date of 12,400 yr B.P. is probably a result of the heat generated by the nuclear bombardment at that time, which would have reset the TL index to zero.) The modified dates for Paleoindian settlements suggest that the timetable for glacial advance sequences, strongly driven by conventional radiocarbon dates, should be revisited in light of the evidence presented here of much older occupations than previously thought."
A large nuclear bombardment should have left evidence elsewhere in the radiocarbon record. It is well known that radiocarbon dates are increasingly too young as we go back in time. The global Carbon Cycle suggests that 14C produced by cosmic rays would be rapidly dispersed in the large carbon reservoirs in the atmosphere, land, and oceans.26 We would expect to see a sudden increase in radiocarbon in the atmosphere that would be incorporated into plants and animals soon after the irradiation; after only a few years, most of the radiocarbon would move into the ocean reservoirs. The 14C level in the fossil record would reset to a higher value. The excess global radiocarbon would then decay with a half-life of 5730 years, which should be seen in the radiocarbon analysis of varved systems.
Fig. 2 plots 14C from the INTCAL98 radiocarbon age calibration data of Stuiver et al. for 15,000-0 yr B.P.27 and Icelandic marine sediment 14C data measured by Voelker et al. for 50,000-11,000 yr B.P.28 Excess 14C is indicated by the difference between the reported radiocarbon dates and actual dates. Sharp increases in 14C are apparent in the marine data at 40,000-43,000, 32,000-34,000 and c. 12,000 yr B.P These increases are coincident with geomagnetic excursionsB that occurred at about 12,000 (Gothenburg), 32,000 (Mono Lake), and 43,000 yr B.P. (Laschamp),29 when the reduced magnetic field would have made Earth especially vulnerable to cosmic ray bombardment. The interstitial radiocarbon data following the three excursions were numerically fit, assuming exponential decay plus a constant cosmic ray-produced component. The fitted half-lives of 5750 yr (37,000-34,000 yr B.P.), 6020 yr (32,000-16,000 yr B.P.), and 6120 yr (12,000-0 yr B.P.) are in good agreement with the expected value.
We also determined that contemporary radiocarbon contains about 7 percent residual 14C left over from the catastrophe. The constant cosmic ray production rate was about 34 percent higher for the Icelandic sediment than the INTCAL98 samples, perhaps implying higher cosmic ray rates farther north. Disregarding fluctuations in the data from variations in ocean temperatures and currents, the results are clearly consistent with the decay of radiocarbon following the three geomagnetic excursions.
In Fig. 2, the sharp drop in 14C activity before 41,000 yr B.P. suggests that global radiocarbon increased by about 45 percent at that time and by about 20 percent at 33,000 and 12,000 yr B.P The results are remarkably consistent with Vogel's comparison of 14C and U-Th dates of a stalagmite that indicates global radiocarbon increased about 75 percent from 30,000 to 40,000 yr B.P. and about 30 percent around 18,000 yr B.P.30
McHargue et al. found high levels of 10Be in Gulf of California marine sediments at 32,000 and 43,000 yr B.P.C that could not be explained by magnetic reversal alone and were attributed to cosmic rays, possibly from a supernova.29 The geomagnetic excursion at 12,500 yr B.P. coincides with the thermoluminescence date from Gainey, and additional evidence for a cosmic ray bombardment at that time is found in the increases of 10Be,31 Ca,32 and Mg32 in Greenland ice cores around 12,500 yr B.P. Similar increases are also seen in the data for NO3-, SO4-, Mg+, Cl-, K+, and Na+ ions in Greenland ice cores.33 This occurrence can be dated precisely to 12,500 ± 500 yr B.P., an average of the remarkably consistent concentration peak centroids in the Greenland ice core data. Significant increases at that time are not found in comparable data for the Antarctic, which indicates that the cosmic ray irradiation was centered in the Northern Hemisphere. Weak evidence of an occurrence at 12,500 yr B.P. is seen in the radiocarbon record for marine sediments near Venezuela,34 confirming that the cosmic ray bombardment was most severe in northern latitudes.
Lunar cosmogenic data also show evidence of increased solar cosmic ray activity at or before 20,000 yr B.P.35,36 although these data are not sensitive to earlier irradiation.
Sonett suggests that a single supernova would produce two or three shock waves, an initial forward shock and a pair of reverse shocks from the initial expansion and a reflected wave from the shell boundary of a more ancient supernova.39,40 Fig. 2 shows that each episode in a series produced a similar amount of atmospheric radiocarbon. The sun lies almost exactly in the center41 of the Local Bubble, believed to be the result of a past nearby supernova event. A candidate for the reverse shock wave is the supernova remnant North Polar Spur, with an estimated age of 75,000 years and a distance of 130 ± 75 parsecs (424 light years),42 conveniently located in the north sky from where it would have preferentially irradiated the Northern Hemisphere. Assuming the Taylor flux is average and 1,000 neutrons are produced per erg of gamma-ray energy,43 the catastrophe would have released about 1016 erg/cm2 (2 x 108 cal/cm2), corresponding to a solar flare of 1043 ergs or a gamma-flash of 1054 ergs from a supernova about 1 parsec away.
The geographical distribution of particle tracks, 235U depletion, and 239Pu concentration shown in Fig. 3 are quite consistent, although the particle tracks seem to be confined to a smaller geographic area. They indicate energy released over the northeastern sector of the U.S., with maximum energy at about 43° N, 85° W, the Michigan area of the Great Lakes region.
Wdowczyk and Wolfendale44 and Zook36 propose, based on the existing record of solar flare intensities, that solar flares as large as 3 x 1038 ergs should be expected every 100,000 years. Clark et al. estimate that supernovas release 1047-1050 ergs within 10 parsecs of Earth every 100 million years.45 Brackenridge suggests that a supernova impacted the earth in Paleoindian times.46 Damon et al. report evidence from the 14C tree ring record that SN1006, which occurred at a distance of 1300 parsecs, produced a neutron shower of 2 x 108 n/cm2.47 Castagnoli et al. report evidence of the past six nearby supernovae from the thermoluminescence record of Tyrrhenian sea sediments.48 Dar et al. suggest that a cosmic ray jet within 1000 parsec would produce 1012 muons/cm2 (greater than 3 x 109 eV) and 1010 protons and neutrons/cm 2 (greater than 106 eV) and deposit over 1012 erg/cm2 in the atmosphere every 100 million years.49 A cosmic ray jet is also predicted to produce heavy elements via the r-process and could be a source of 235U enriched up to 60 percent in uranium.
The Paleoindian catastrophe was large by standards of all suspected cosmic occurrences. Normal geomagnetic conditions would focus cosmic rays towards the magnetic poles, concentrating their severity in those regions. However, low magnetic field intensity during a geomagnetic excursion may have allowed excessive cosmic rays to strike northeastern North America. (Whether the geomagnetic excursion admitted cosmic radiation, or the radiation caused the excursion, is uncertain. Given our present state of knowledge, cause and effect in this instance are unclear.) The presence of a nearby small and dense interstellar cloud may explain the origin of the particle bombardment.50 The size of the initial catastrophe may be too large for a solar flare, but a sufficiently powerful nearby supernova or cosmic ray jet could account for it. It appears that the catastrophe initiated a sequence of events that may have included solar flares, impacts, and secondary cosmic ray bombardments.
The enormous energy released by the catastrophe at 12,500 yr B.P. could have heated the atmosphere to over 1000°C over Michigan, and the neutron flux at more northern locations would have melted considerable glacial ice. Radiation effects on plants and animals exposed to the cosmic rays would have been lethal, comparable to being irradiated in a 5-megawatt reactor more than 100 seconds.
The overall pattern of the catastrophe matches the pattern of mass extinction before Holocene times. The Western Hemisphere was more affected than the Eastern, North America more than South America, and eastern North America more than western North America.51,52,53 Extinction in the Great Lakes area was more rapid and pronounced than elsewhere. Larger animals were more affected than smaller ones, a pattern that conforms to the expectation that radiation exposure affects large bodies more than smaller ones.54,55 Sharp fluctuations of 14C in the Icelandic marine sediments at each geomagnetic excursion are interesting; because global carbon deposits in the ocean sediments at a rate of only about 0.0005 percent a year, a sudden increase in sediment 14C may reflect the rapid die-off of organisms that incorporated radiocarbon shortly after bombardment.
Massive radiation would be expected to cause major mutations in plant life. Maize probably evolved by macro-mutation at that time,55,56 and plant domestication of possibly mutated forms appears worldwide after the Late Glacial period. For example, there was a rapid transition from wild to domesticated grains in the Near East after the catastrophe.57
Much of what we assume about the Paleoindian period and the peopling of the Americas has been inferred from conventional radiocarbon chronology, which often conflicts with archaeological evidence. This work mandates that conventional radiocarbon dates be reinterpreted in light of hard terrestrial evidence of exposure of the radiocarbon samples to a cosmological catastrophe that affected vast areas of North America and beyond. A nuclear catastrophe can reset a group of unrelated artifacts to a common younger date, creating gaps and false episodes in the fossil record. Geographical variation and complicated overburdens may further confuse the interpretation. Scrutiny of Paleoindian artifacts and the North American paleolandscape, associated stratigraphic sediments, coupled with continued radiological investigations, may provide more evidence for the cosmic catastrophe and new clues to the origin of Paleoindians.
"...Is there any possibility that Carolina Bays could have been formed by a tsunami depositing huge icebergs, which then melted leaving these gouges, or if covered by inwashed dirt, leaving a depression?..."
I considered this possibility some years ago. The theory is enticing, but I had to reject it in light of what I discovered about how Carolina Bays are arranged on the land. See my post #119.
Although the Bay Rims date from the Pleistocene-holocene boundary, the bays themselves do not.
How can this possibly be? You'll probably need to go slow here with this ol' East Texas country boy. But, I have an open mind however, so I'm trainable.
They are contemporaneous with the fluviomarine terraces upon which they occur, and therefore, were not all formed at once, but sequentially; as sea level dropped and each new terrace was exposed, new bays were formed.
You're suggesting the bays were laid down over a period of hundreds, maybe thousands of years? Some within others? And different sizes; many overlapping? But the rims are all the same age??? I understand and appreciate your familiarity with the bays, but you'll forgive my skepticism?
You recall those 100 pound hailstones mentioned in the Bible(and possibly elsewhere)? To be honest, that seems as plausible as anything else I've read so far. And that's my story and I'm stickin' to it ;^)
FGS
The problem as I understand with that conclusion is there have been no other indicators found from an impactor.........NONE. At least that I've run across in my searches. But who knows. Renfield is doing his best to explain all this in natural, make that, terrestial terms; I'm sure he gets frustrated. He has his own hypothesis that just sounds weird to me; being a layman ;^)
Thanks Fred. Keep 'em coming. I may as well move my computinmachine into the kitchen; like in front of the fridge, so's I won't have to get up and leave to eat. On second thought...........
Back about '97 or '98 I read a paper (unfortunately, I've forgotten the author and journal, but I could probably hunt it up eventually) on bay rims in South Carolina. The researcher dated them to the P-H boundary (perhaps by Optical Stimulation Luminescense?). Formation of rims is pretty easy to understand. 12,000 to 10,000 years ago, most of North America was both colder and windier than it is now. There were still trees in South Carolina, but they would have been more thinly spread than today, sort of like a Savannah. Bays, being depressional areas, were wetter than the surrounding higher areas, and would have supported much denser stands of trees. These denser stands of trees acted like windbreaks; when wind slows down, it drops much of its aeolian load, and indeed, the thickest portions of bay rims are along the southeastern edges of bays, which would have been in the lee of prevailing winter winds. (This is similar to snow drifts forming on the lee side of a hedge or fence). The woody vegetation in bays was (and is) different from that of the surrounding upland areas, too; deciduous evergreens like Red Bay, Loblolly Bay, Sweet Bay, Dahoon, Ti-Ti, etc, while the vegetation on the uplands was dominantly oak-hickory...trees that would lose their leaves during the winter. The Bays were very effective windbreaks.
As for the ages of bays themselves, I think that was from a paper by Ray Daniels and Ehrling Gamble circa 1967. The copies weren't mine, they belonged to one of my colleagues, so it would take me some effort to track them down.
Aeon Flux, however, is rather nice. Tempermental though. And short-lived.
Well, not entirely. The Alaska "bays" are not nearly as uniform in shape or length/width dimensions. Seems the folks studying the Alaska bays haven't reached a conclusion yet as to what actually creates their bays either. Butt crack ice(cracking the bedrock) and thawing seems to be the most widely accepted hypothesis.
...if you drill down through the various stranded barrier dunes and back-barrier flats along the coast of South Carolina today, you will find buried carolina bays.
You're talking barrier islands/strips? Backfilled by wave action? Hurricanes? Tusnamis? Rising oceans? Even so, does that necessarily rule out aerial fireworks? Like I said, you'll need to go slow with this ol' East Texas country boy ;^)
BTW, I'm sure you're familiar with the other "bays" around the world. After doing some additional searching, there seems to be a bunch of these things around. MANY of them nowhere near a present or historic/prehistoric shoreline. Some aligned parallel with a shoreline; some at elevations of a thousand feet; maybe more. Thoughts? Best I can tell the one thing they seem to have in common is they have been located(the visible ones?) on soft soil. Sandy lome and the like??? I suppose if sand dunes didn't change so much they might be good candidates for finding visible bays.
This is giving me a headache. Think I'll take a nap.
"....You're suggesting the bays were laid down over a period of hundreds, maybe thousands of years? Some within others? And different sizes; many overlapping? But the rims are all the same age??? I understand and appreciate your familiarity with the bays, but you'll forgive my skepticism?..."
I am indeed. And I think I have a good theory to explain it. I'm reluctant to post it all here, partially because it would require a lot of drawings and illustrations, and partially because I'm mulling over the possiblity of going back to school for my PhD in geomorphology, and I don't want someone else to steal my research idea out from under me. However, if you are ever in my area and would like to meet me in person, I'll be glad to talk your ear off about it. :)
"...You're talking barrier islands/strips? Backfilled by wave action? Hurricanes? Tusnamis? Rising oceans? ..."
Yes, yes, yes, yes, and more. Once sea level becomes relatively stable for a while, barrier islands form along continental edges of low gradient (such as along our eastern and southeastern coasts). Backbarrier areas accrete soil and soil-forming material rapidly; this includes wind-and wave-deposited mineral material, as well as organic detritus from saltmarsh vegetation (and the saltmarsh vegetation itself acts as a filter to trap suspended sands, silts and clays). One of my colleagues at the Smithsonian Environmental Research Center, in neighboring Anne Arundel County, has measured >14 feet of Holocene deposition (mostly organic) in a saltmarsh along the Chesapeake Bay. This rate of deposition is by no means unusual.
By the way, I'm convinced that earth is frequently (on a geologic time scale) bombarded by various metorites and cometary fragments. I just don't think such bombardment is responsible for Carolina Bays.
IOW, the bays walk, look and act like a duck to the layman(that would be me), that is, it looks for all the world like something took a swipe at the eastern seaboard(amongst other places???) at roughly the P/H boundary. If you're sayin' it ain't a duck, the arguments will necessarily have to be ironclad. Or maybe handed down from the mount. Coulda's and woulda's are great for purposes of discussion, but.....
Again, you'll forgive my skeptcism???
FS
"....Well, not entirely. The Alaska "bays" are not nearly as uniform in shape or length/width dimensions..."
Perhaps not all of them are, but the ones I saw on that poster were very uniform, and appeared to be perfectly elliptical. I was struck by their uniformity and symmetry.
"...Seems the folks studying the Alaska bays haven't reached a conclusion yet as to what actually creates their bays either. Butt crack ice(cracking the bedrock) and thawing seems to be the most widely accepted hypothesis...."
Well, perhaps. Geologists and geomorphologists tell me that there was no permafrost, and no glacial ice, in the Carolinas and Georgia, even during the glacial maxima. It would be surprising if two wildly divergiant geomorphic mechanisms produced such similar results. I suspect that when we finally solve this puzzle, we will find tht the bays of both areas have the same, or very similar, causes.
Can't blame you for that and good luck!
However, if you are ever in my area and would like to meet me in person, I'll be glad to talk your ear off about it. :)
The offer is much appreciated, but I would run out of gas on the subject in short order. My career(s) have been in the financial and sales fields for the most part, and while I have a keen interest in past happenings on our globe, I know little about it, but I'm trying to catch up. Debating experts is good exercise for me. Thanks again for your efforts.
Now I've really got to do something about this headache.
FGS
Certainly I forgive your skepticism; you should see the arguments we soil scientists get into amongst ourselves (there's an old saying that if you put 2 soil scientists into a pit, you get 3 opinions).
Remember that pines are not climax vegetation anywhere on the coastal plain. They are colonizing species, and depend upon fire, or other disturbance, to keep out competing hardwoods. Palynological evidence shows that Oaks and Hickories were the dominant arboreal species on the coastal plain of the Carolinas during the Pleistocene, and dry, sandy uplands are climaxed by Oaks, Hickories, and Dogwood today as well. Indians burned large areas to open up the forest and improve hunting (as well as to make garden space for themselves), and pines came in. Even today, foresters have to burn areas periodically to keep them in pines.
OKG!! Mother Nature has nukes!! We're all DOOMED, DOOMED I TELL YOU!!
To avoid having to calculate the years everytime the subject comes up, I'm guessing. And to place it in a timeline.
Points taken re the forestry characteristics in your area. I suppose I would need to get with a local East Texas forestry agent to find out why things work a little differently in these "piney" woods. Not being on a coastal plain might have something to do with it, although we don't miss it by much.
Not to worry; the radiation is minimal but you'll really need to watch out for those incoming hailstones. One of those could mess up your whole day.
I have witnessed three seperate meteor events. Two were quite a ways west of me. One went right over my head. Now, when a meteor goes over your head, and lights up the sky like daylight, you take notice. The other two were equally as eventful as both were quite incredible explosions. One, off the coast of California, that I could see from Oklahoma, the other happened over New Mexico. All three were in the late 90's while I delivered newspapers at night. I heard on the news after the California meteor that it apparently woke people from sound sleep, and may have caused some electical disturbances as well.
I heard on the news after the California meteor that it apparently woke people from sound sleep, and may have caused some electical disturbances as well.
Now that's interesting. One would suspect some sort of electrical disturbances from one of these things, particularly a big one, but I've not read enough about 'em to know if there's been any research. The static discharge as these things pass through the atmosphere must be tremendous, but what about when they get near the surface??? Lightning bolts??? There may be some interesting stuff out there; I just haven't taken the time to look for it.
Thanks for stopping by and the input.
Yellowstone, another "toba"
Yes, I am very aware of that situation. In fact my father wrote an entire, very long and wordy, novel on the subject. In it he postulates a man, like himself, becoming aware of the danger, and moving operations to the Carolina's. Then it blows and a whole lot of adventures after that. Some day I may take it and rewrite it and possibly get it published. Actually, his interest was one of the things that restimulated my active interest in volcanism.
Regarding Neanderthals, there were some recent FR threads about the discovery of some N genes in the Scottish population, and perhaps other northerners. About 40% of the population, and virtually all the redheads. My husband was Scottish ancestry, very redhead and blue eyed (a positive adaptation to diminished sunshine and Vitamin D formation), heavy brow ridges, large dense bones, short legs and long torso (good for cold climates), very hairy, and warrior temperment. I always thought he might have some neanderthal ancestry, and now I am almost certain. One of our sons has his size and density, but none of his coloring. He is currently in Afghanistan. One of our sons also has the same body density, like a pit bull, if you have ever felt one. I think some Ns may have interbread with other groups moving north, as the pale coloring would have had positive survival value until the blond gene showed up which has the same Vitamin D value, enabling women to develop broad childbirth friendly pelvises.
Regarding Flores person, I think that the island must have been much larger when the ice age ended, with the water 400 feet lower than now. As melting caused the sea to rise the people and other animals were forced into a smaller and smaller area, and miniturization enabled them to survive with fewer resources. I think other large animals also miniturized. I think this happened on Malta with elephants.
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