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... Science Frontiers ONLINE No. 18: Nov-Dec 1981 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Iridium-rich layers and catastrophism Kyte et al have discovered a 2.3 -millionyear-old sedimentary layer under the Antarctic Ocean that contains iridium and gold concentrations comparable to those in the Cretaceous-Tertiary boundary. The noble metals are mostly contained in millimeter-sized grains that resemble ablation debris from a large extraterrestrial object. Unlike the Cre taceous-Tertiary episode, however, the newly found layer is not accompanied by evidence of mass biological extinctions. (Kyte, Frank T., et al; "High Noble Metal Concentrations in a Late Pliocene Sediment," Nature, 292:417, 1981.) Comment. Perhaps those ... who deny the existence of sudden biological extinctions at the CretaceousTertiary boundary are correct and something else besides catastrophism impacted terrestrial life at that juncture. Reference. The implications of iridium "spikes" are found in Category ESB1 in our Catalog: Anomalies in Geology. To order, go to: here . From Science Frontiers #18, NOV-DEC 1981 . 1981-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 15: Spring 1981 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Iceland And The Iridium Layer The high concentration of iridium between the Cretaceous and Tertiary eras (about 65 million years ago) is widely interpreted as indicating a worldwide catastrophe caused by the impact of a comet or meteor. The increase of iridium concentration over normal levels is much higher in northern latitudes, suggesting that the impact point is in this region. But no impact scar of the proper size and age exists. However, if one looks for scabs rather than scars, one finds that Iceland is formed entirely of volcanic rocks younger than the Cretaceous. To Fred Whipple of the Smithsonian Astrophysical Observatory, these facts dovetail nicely. Iceland was form ed by ... welling up from a 100-km hole in the sea floor blasted out by a 10-km meteor. (Anonymous; "The Blow That Gave Birth to Iceland?" New Scientist, 89:740, 1981.) From Science Frontiers #15, Spring 1981 . 1981-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 8: Fall 1979 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Iridium And Mass Extinctions Alvarez and his colleagues at the University of California, while chemically analyzing a series of sedimentary strata from Italy, discovered that one layer had 25 times the concentration of iridium residing in adjacent strata. The iridium-rich layer forms the boundary between the Cretaceous and Tertiary periods, 65 million years ago. During that death-filled interval, 50% of the earth's genera were wiped out. Such are the two correlated facts: iridium increase and mass extinction. But do they have the same cause? Alvarez et al point out that iridium is rare on earth but much more common out in space. The anomalous concentration ... iridium could have been injected by a massive solar flare, a big meteor impact, or come other extraterrestrial catastrophe. Thus is catastrophism being resurrected. (Anonymous; "An Iridium Clue to the Dinosaur's Demise," New Scientist, 82: 798, 1979.) From Science Frontiers #8 , Fall 1979 . 1979-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 67: Jan-Feb 1990 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Microorganisms complicate the k-t boundary Ancient bacteria, it appears, have tampered with the K-T (Cretaceous-Tertiary) boundary of some 65 million years ago. A key marker of this boundary is a thin "spike" of iridium that is found worldwide, and which was supposedly deposited by the asteroid impact that helped finish off the dinosaurs. For many scientists, the asteroid-impact scenario has become a "non-negotiable" brick in the Temple of Science. The problem they have faced is that the iridium layer is variable in thickness and concentration from site to site. Sometimes iridium can be detected well above and ... the K-T boundary. This variability has tended to undermine the asteroid-impact theory. Recent experiments at Wheaton College by B.D . Dyer et al have demonstrated that bacteria in ground water can both concentrate and disperse iridium deposits. In other words, bacteria could smear out an iridium spike, perhaps partially erase it, or even move it to a deeper or shallower layer of sediment. (Monastersky, R.; "Microbes Complicate the K-T Mystery," Science News, 136: 341, 1989.) Comment. An obvious question now is how bacteria might have affected other chemicals, such as oxygen and carbon isotopes, widely used in stratigraphy. From Science Frontiers #67, JAN-FEB 1990 . 1990-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 60: Nov-Dec 1988 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Global fire at the k-t boundary The worldwide deposit of iridium at the K-T (Cretaceous-Tertiary) boundary has been considered very strong evidence that a large astronomical object (asteroid or comet) devastated our planet some 65 million years ago. Some scientists, however, propose that the iridium layer was instead deposited through widespread volcanic activity. The proponents of an astronomical mechanism should be heartened by a recent paper in Nature, by W.S . Wolbach et al. Here is their Abstract: "Cretaceous-Tertiary (K -T ) boundary clays from five sites in Europe and New Zealand are 102 -104 - ... enriched in elemental C (mainly soot), which is isotopically uniform and apparently comes from a single global fire. The soot layer coincides with the Ir layer, suggesting that the fire was triggered by meteorite impact and began before the ejecta had settled." The composition of the hydrocarbons in the sediments points to the earth's biomass (mainly surface vegetation) as the source of the soot. The total quantity of K-T soot is equivalent to that which would be produced by burning 10% of all present terrestrial plant material. (Wolbach, Wendy S., et al; "Global Fire at the Cretaceous-Tertiary Boundary," Nature, 334:665, 1988.) Comment. Unmentioned in the above article is the possibility that extensive wildfires might have been generated ...
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... Science Frontiers ONLINE No. 85: Jan-Feb 1993 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Two Tsumani Tales Only a few years ago astronomical catastrophism was denied as a major factor in geological change. Now one reads everywhere of huge terrestrial impact craters, iridium layers, and tektite deposits. Even so, one necessary consequence of 70% of the large impacts has been neglected until recently: the giant tsunamis and marine incursions that must have swept over the coasts of the continents following impacts at sea. This oversight is now being rectified. 100,000 BP. The South Pacific. A longstanding geological enigma of the New South Wales coastline is the curious distribution of sand dunes. Those headlands less than 40 meters high have lost most ... their dunes, leaving only raw, unweathered rock. On the other hand, the higher headlands have retained these dunes. Australians B. Young and T. Bryant hypothesize that a tsunamis 40 meters high swept the lower headlands clean about 100,000 years ago. They can even plot the incoming wave's direction, because a few remnants of the coastal dunes still cling to the southwest corners of the headlands along the NSW coast south of Newcastle. In their scenario, the tsunamis came from the northeast, smashed into the Solomons, southeastern Australia, and northeastern New Zealand. The Great Barrier Reef protected northeastern Australia from the full force of the wave. Young and Bryant favor a Hawaiian landslip as the initiator of the tsunamis, but acknowledge that an asteroid impact could also have done the ...
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... T. Hallam raises still more objections: Tropical plants, mammals, crocodiles, birds, and benthic invertebrates were little affected by whatever happened at the Cretaceous-Tertiary interface. Furthermore, many groups that were extinguished were already well into a decline. Some geologists insist that some of the supposedly synchronous extinctions were probably separated by several hundred thousand years; viz., plankton and dinosaurs. The vaunted iridium anomaly in deep-sea cores is spread through a considerable thickness of sediment. Even after allowing for the mixing of sediments, the iridium-rich layer is thousands of years thick. According to the asteroid scenario, the clay layer separating the Cretaceous from the Tertiary should represent the fallout from impact-raised dust, which would include asteroidal material and a mixed sample of earth rocks. However ... in Denmark, the boundary is marked by the so-called Fish Clay, which is almost pure smectite -- a single mineral and not a mixture of terrestrial rock flour. If it wasn't an asteroid impact, why the iridium concentration? At least three hypotheses have been proposed to circumvent the asteroid debacle: (1 ) volcanic activity; (2 ) a concentration of micrometeorites, thousands of tons of which fall each day, through extreme reduction of sedimentation; and (3 ) selective enrichment of iridium by an anoxic environment acting upon kerogenand pyrite-rich clay. In short, some geologists at least do not find the asteroid hypothesis compelling at the moment. (Hallam, Tony; "Asteroids and Extinction -- No Cause for Concern," New Scientist, p. ...
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... Science Frontiers ONLINE No. 23: Sep-Oct 1982 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The cretaceous-tertiary extinction bolide The recently discovered worldwide iridium-rich layer is taken by many scientists as evidence of the collision of an asteroid or comet with the earth about 65 million years ago. This cataclysmic event is also blamed (by some, at least) for the apparent sudden biological extinctions recorded on these pages of the fossil record. In this setting, the authors of this paper calculate the effects on the earth of a 10-kilometer-diameter object impacting at about 20/km/sec. Do the theoretical results jibe with the geological and paleontological data? Very definitely. Crater ejecta rich in extraterrestrial material would be ... to an altitude of 10 km, where winds would insure global distribution. In terms of biological stress, the 10-km projectile would transfer 40-50% of its kinetic energy to the atmosphere, creating a heat pulse that could raise global temperatures 30 C (50 F) for several days. Many large animals might well succumb to such a temperature transient. In addition, the protective ozone layer might be blown away by shock waves and not reform for a decade. (O 'Keefe, John D., and Ahrens, Thomas J.; "Impact Mechanics of the Cretaceous-Tertiary Extinction Bolide," Nature, 298,123, 1982.) Reference. We catalog biological extinctions at ESB1 in Anomalies in Geology. To order this book, visit: here . ...
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... Science Frontiers ONLINE No. 26: Mar-Apr 1983 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Punching A Hole In The Asteroid Hypothesis Scientists have long searched for a cause for the profound geological and biological changes that apparently occurred between the Cretaceous and Tertiary periods. When an iridium-rich layer was found in several areas at this important boundary, many claimed it as proof of an asteroid impact or some other catastrophism that would nicely explain the massive worldwide changes that occurred. With this preamble in mind, consider the following abstract from an article in Science: "Analyses of the clay mineralogy of samples from the Cretaceous-Tertiary boundary layer at four localities show that the boundary clay is neither mineralogically exotic nor distinct from locally derived clays above ... below the boundary. The significant ejecta component in the clay that is predicted by the asteroid impact scenario was not detected." (Rampino, Michael R., and Reynolds, Robert C.; "Clay Mineralogy of the Cretaceous-Tertiary Boundary Clay," Science, 219:1983.) From Science Frontiers #26, MAR-APR 1983 . 1983-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 43: Jan-Feb 1986 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The Cretaceous Incineration The worldwide deposit of iridium at the end of the Cretaceous implies, to many at least, that the great biological extinctions of this period were the consequence of a meteorite impact. It has now been discovered that clay samples from the Cretaceous-Tertiary boundary also contain 0.36-0 .58% graphitic carbon. It is fluffy stuff and suggests that the planet was once covered by a thick layer of soot. Quantitatively, the soot layer is equivalent to the carbon in 10% of the earth's present biomass. The authors speculate that this soot was created by huge wildfires that consumed much of the earth ... s vegetation and perhaps fossil fuel as well. Terrestrial life was, of course, devastated -- just as it is in the currently popular "nuclear winter" scenarios. The end-of-the-Cretaceous soot is in fact, thicker and more widely spread than nuclear winter theories predict. (Wolbach, Wendy S., et al; "Cretaceous Extinctions: Evidence for Wildfires and Search for Meteoric Material," Science, 230:167, 1985.) Comment. Questions arise, though: How could a single meteorite impact ignite worldwide wildfires? Why haven't other meteorite impacts, recorded abundantly by large craters and astroblemes, also set fire to the planet and left iridium layers? From Science Frontiers #43, JAN-FEB 1986 . 1986-2000 William R ...
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... Other pages Home Page Science Frontiers Online All Issues Last Issue Next Issue Sourcebook Project Sourcebook Subjects Contents Archaeology The Senegambian Megalithic Monument Complex A Celtic Frontier Site in Colorado? Astronomy A Bump in the Cosmic Background Phoebe Not Locked to Saturn Biology Descent of Man -- or Ascent of Ape? Life's Origin Within the Earth? Or Did it Drift in From Without? Geology The Burgess Shale Puzzle Iridium-rich Layers and Catastrophism Geophysics The Long Arms of Venus and Jupiter Giant Thunderstorm Clusters Offshore Booms Are Still with Us Psychology Dreams More Real Than Reality Warts on Demand? ...
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... Issues This Issue Sourcebook Project Sourcebook Subjects The Rise Of Astronomical Catastrophism After being ridiculed for well over a century, astronomical catastrophism is now coming into its own. First, there was the admission that a few small craters, like Meteor Crater in Arizona, just might be of meteoric origin; then, more and bigger craters (astroblemes) were recognized; and, recently, the discovery of the iridium-rich layer at the Cretaceious-Tertiary boundary has made the subject very popular, as evidenced by the following three items: A long, very thorough and scientific review of geological and biological changes caused by meteor strikes throughout the earth's history. (McLaren, Digby J.; "Bolides and Biostratigraphy," Geological Society of America, Bulletin, 94:313, 1983. ... A shorter, popular version of the above. (McLaren, Digby; "Impacts That Changed the Course of Evolution," New Scientist, 100:588, 1983.) Evidence is growing that the collision of planetary material with the Earth can profoundly affect local geology, and that impacts of very large meteorites may have influenced the evolution of the Earth and the life that exists upon it. This quotation is from the lead-in to the article references below, which also has a nice world map of major impact sites over 1 km in diameter. (Grieve, Richard; "Impact Craters Shape Planet Surfaces," New Scientist, 100:516, 1983.) Reference. Terrestrial cratering phenomena are cataloged in Chapter ETC in Carolina Bays, Mima Mounds. For details about this ...
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... ?" His certainty was shaken, however, when he began mapping fossil deposits on Seymour Island, Antarctica. He didn't find the dinosaur bones but rather a giant bed of fish bones at least 50 square kilometers in area. Some sort of catastrophe must have annihilated untold millions of fish. And guess what? This great bone bed was deposited directly on top of that layer of extraterrestrial iridium that marks the 65-million-year-old Cretaceous Tertiary boundary at many sites around the world. (Hecht, Jeff; "The Island Where the Fish Had Their Chips," New Scientist, p. 16, November 11, 1995) Cross reference. Bone beds of fish and other creatures are filed under ESB13X2 in Anomalies in Geology. To order this catalog, see here ... Science Frontiers ONLINE No. 104: Mar-Apr 1996 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects An Antarctic Bone Bed W. Zinsmeister was accustomed to scoff at the idea that the Age of Dinosaurs ended violently with the impact of a giant asteroid some 65 million years ago. He always asked: "Where's the layer of burnt and twisted dinosaur bones?" His certainty was shaken, however, when he began mapping fossil deposits on Seymour Island, Antarctica. He didn't find the dinosaur bones but rather a giant bed of fish bones at least 50 square kilometers in area. Some sort of catastrophe must have annihilated untold millions of fish. And guess what? This great bone bed was deposited directly on top of ...
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... Subjects Contents Archaeology Basques in the Susquehanna Valley 2,500 Years Ago? Invention of Agriculture May Have Been A Step Backward Hidden Stonehenge Atlantis Found -- again Astronomy Distant Galaxies Look Like Those Close-by "tired Light" Theory Revived Those Darn Quarks Biology If Bacteria Don't Think, Neither Do We The Evolutionary Struggle Within Geology Is All Natural Gas Biological in Origin? Iceland and the Iridium Layer Geophysics The Novaya Zemlya Effect Massive Ice Lump Falls on England Psychology Is Your Brain Really Necessary? ...
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... Science Frontiers ONLINE No. 65: Sep-Oct 1989 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Chemical surprises at the k-t boundary The presence of high iridium concentrations at the Cretaceous-Tertiary (K -T ) boundary, some 65 million years ago, has led to the widely accepted notion that an extraterrestrial projectile slammed into the earth at that time, wreaking geological and biological havoc. But the K-T boundary is anything but simple chemically and paleontologically. To illustrate, J.L . Bada and M. Zhao have found unusual amino acids in sediments laid down before and after this geological time marker. "They find that Danish sediments spanning the narrow boundary layer contain two amino acids, alpha-aminoisobutyric acid and ... , that are relatively uncommon in biological materials but abundant in the organicrich meteorites. They suggest that the body which collided with Earth 65 million years ago and left the telltale iridium residue may have been organic-rich, perhaps like a C-type asteroid or a comet. Such a possibility has interesting implications for the extinction and related atmospheric effects, and supports the idea that impact events could have supplied the Earth during a much earlier period with the raw materials for organic chemical evolution." Actually, the above quotation is pretty much in line with present mainstream thinking. Perhaps so, but Bada and Zhao identified two troubling anomalies. First, the amounts of amino acids found were surprisingly high. How could these complex molecules survive the searing temperatures engendered by high-velocity impact? Second, ...
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... absence of a smoking gun (a sufficiently large terrestrial crater with an age of 65 million years) has allowed volcanists to deny the cosmic catastrophists a complete victory. However, the recent identification of tektite-like glasses at the Cretaceous-Tertiary boundary (KTB) on Haiti is leading geological detectives closer and closer to the missing crater. Elsewhere in the world, the KTB is characterized by an iridium anomaly and a thin layer of "impact clay" consisting of tiny bits of shocked minerals. At Beloc, on Haiti, though, geologists find a 55-centimeter-thick layer of glassy debris. Approximately 25% of this stra tum consists of 1-6 -millimeter particles of tektite-like glass. Most of the glass particles are spherical, but a few have the splash ... forms and dumbbell shapes of bona fide tektites. The thickness of the Haitian deposit and the large sizes of the particles suggest that the smoking gun must be nearby. Ironically, the Haiti stratum was originally classified as of volcanic origin; and we must add that we are presenting here only the conclusions of the asteroid school. But where oh where is this crater? The Manson crater in Iowa (now buried) is of the right age but too small. The best candidate so far is buried in northern Yucatan. The Chicxulub crater is discernible on gravity- and magneticanomaly maps and is probably of the right age. Only drilling will confirm the guilt of the suspect. Even if Chicxulub is the culprit, much debate prevails over exactly how the dinosaurs were done in. Was it a " ...
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... a comeback, as illustrated by the following back-to-back articles in Nature. We quote from the abstracts. "Closely spaced samples from an uninterupted calcareous pelagic sequence across the Cretaceous-Tertiary boundary reveal that the extinction of planktonic Foraminifera and nannofossils was abrupt without any previous warning in the sedimentary record, and that the moment of extinction was coupled with anomalous trace element enrichments, especially of iridium and osmium. The rarity of these two elements in the crust of the Earth indicates that an extraterrestrial source, such as the impact of a large meteorite may have provided the required amounts of iridium and osmium." (Smit, J., and Hertogen, J.; "An Extraterrestrial Event at the Cretaceous-Tertiary Boundary," Nature, 285:198, 1980.) ... Science Frontiers ONLINE No. 12: Fall 1980 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The Rehabilitation Of Cuvier Cuvier (1769-1832) was a catastrophist. To him, the record of death in the layers of fossiliferous rocks was obviously the consequence of terrestrial convulsions. But Cuvier's ideas were swept aside by the uniformitarians who saw the earth and its cargo of life unfolding with almost agonizing slowness. But Cuvier is making a comeback, as illustrated by the following back-to-back articles in Nature. We quote from the abstracts. "Closely spaced samples from an uninterupted calcareous pelagic sequence across the Cretaceous-Tertiary boundary reveal that the extinction of planktonic Foraminifera and nannofossils was abrupt without any previous warning in the sedimentary record ...
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... Washed Up," New Scientist, p. 26, November 7, 1998.) Comments. Tsunami debris from the end-Cretaceous impact has been found along the Gulf Coast and on some Caribbean islands. In northeastern Mexico, geologists have found a debris layer 3-meters thick that is also of the right age. This layer contains tektites, glass spheres, plant material, and an iridium anomaly. (SF#85) However, these debris deposits can hardly compare to the far-inland Arkansas sandstone chunks. From Science Frontiers #121, JAN-FEB 1999 . 1999-2000 William R. Corliss ...
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... splashed into the oceans, leaving no record at all. An updating of the most recent crater data available, such as they are, greatly weakens the case for the popular 28-31 million-year period and strengthens support for a 19-22 million-year period. But neither cycle is in synchronism with the famous K-T (Cretaceous-Tertiary) Boundary, with its perplexing iridium layer and massive biological extinctions. In fact, say V.L . Sharpton et al, the entire known cratering record could well be the consequence of chance encounters between the earth and stray meteors and comets. Thus would pass the periodicities of this world! (Sharpton, V.L . et al; "Periodicity in the Earth's Cratering Record?" Eos, 68: ... , 1987.) Reference. More details on crater periodicity may be found in ETC4 in our catalog: Carolina Bays, Mima Mounds. For information on this book, see: here . From Science Frontiers #52, JUL-AUG 1987 . 1987-2000 William R. Corliss ...
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... . A similar patter of magnetic rings has shown up in the Yucatan peninsula. The inner ring is 60 kilometers across; the second, 180 kilometers. The rocks causing the magnetic anomalies are about 1100 feet down. Since these rocks are probably Late Cretaceous in age, this potential impact feature may be the eagerly sought scar of the asteroid impact that some think wiped out the dinosaurs and left an iridium-rich layer all over the world. (Anonymous; "Possible Yucatan Impact Basin," Sky and Telescope, 63:249, 1982.) From Science Frontiers #21, MAY-JUN 1982 . 1982-2000 William R. Corliss ...
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... Buildings and cars seem to be swallowed fairly regularly by Florida sinkholes.) Petuch disagrees with the collapse theory and points to the following evidence for an impact origin: 1. The presence of a strong positive magnetic anomaly; 2. Eocene formations, 40 million years old, are missing over the southern Everglades; 3. A network of fractures pervades rock layers older than Eocene; 4. High iridium concentrations, probably of extraterrestrial origin, exist at the Eocene-Oligocene boundary on nearby Barbados; and 5. The oval reef structure that seems to have grown around the impact area as sealevels rose. Some geologists do not concur with the asteroid theory, but they are all reviewing Florida's geological history in a new light. (Weisburd, S.; "Asteroid Origin of the ... caused by groundwater dissolving away limestone. (Buildings and cars seem to be swallowed fairly regularly by Florida sinkholes.) Petuch disagrees with the collapse theory and points to the following evidence for an impact origin: 1. The presence of a strong positive magnetic anomaly; 2. Eocene formations, 40 million years old, are missing over the southern Everglades; 3. A network of fractures pervades rock layers older than Eocene; 4. High iridium concentrations, probably of extraterrestrial origin, exist at the Eocene-Oligocene boundary on nearby Barbados; and 5. The oval reef structure that seems to have grown around the impact area as sealevels rose. Some geologists do not concur with the asteroid theory, but they are all reviewing Florida's geological history in a new light. (Weisburd, ...
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