6 results found.
... 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 Everglades astrobleme?Astrobleme means "star wound," and the southern tip of Florida seems to have been wounded by an asteroid or some other celestial projectile. At a recent meeting of the Geological Society of America, E.J . Petuch proposed that the Everglades region received a direct hit from an asteroid about 36 million years ago. The Everglades region is a swampy, forested area surrounded by an oval-shaped system of ridges. Geologists usually maintain that the Everglades represent a collapse feature 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, S.; "Asteroid Origin of the Everglades?" Science News, 128:294, 1985.) Reference. Very large craters and astroblemes ...
Terms matched: 1 - Score: 82 - 15 May 2017 - URL: /sf043/sf043p15.htm
... of the Stratigraphic Record ESR2 Lateral Variations in Strata ESR3 Apparently-Inverted Strata ESR4 Near-Global Unconformities ESR5 Rythmites and Cyclothems ESR6 Undisturbed and Unconsolidated Ancient Sediments ESR7 Vertical Stacking of Deposits ESR8 Continent-Type Rocks in the Ocean Depths ESR9 Exotic Terranes ESR10 Long Belts of Igneous and Metamorphic Rocks ESX PIERCEMENT STRUCTURES, INTRUSIVES, EXTERNAL IMPRESSIONS ESX1 Polystrate Fossils ESX2 Diapir Anomalies ESX3 Anomalies of Stigmaria ESX4 Perplexing Intrusives ESX5 Unusual Striations Attributed to Ice-Sheet Action ESX6 Anomalous Superficial Markings ET TOPOGRAPHIC ANOMALIES ETB BAYS, LAKES, SMALL DEPRESSIONS ETB1 Oriented Lakes and Depressions ETB2 Anomalous Features of Potholes ETB3 Fluid-Vent Craters ETB4 Gilgai Topography ETB5 Mountain-Top Depressions ETB6 Horseshoe-Shaped Depressions ETB7 Cookie-Cutter Holes ETB8 "Bottomless" Pits ETB9 Large Assemblages of Glacial Kettles ETB10 Depressions in Chalk Country ETC CRATERS, ASTROBLEMES, LARGE CIRCULAR STRUCTURES ETC1 Astroblemes (Starwounds) ETC2 Very Large Depressions of Probable Meteoric Origin ETC3 Hypothetical (and Still Undiscovered) Craters ETC4 Periodicity of Crater Ages ETE RAISED BEACHES, FOSSIL CORAL REEFS, TERRACES ETE1 Raised and Submerged Beaches ETE2 Fossil Coral Reefs ETE3 Terraces along Rivers, Submarine Canyons, Sea-Floor Channels ETE4 Inland, High-Level Terraces and Erosion Surfaces ETE5 Periodically Created Beach Terraces ETH GUYOTS, PLATEAUS, UNUSUAL MOUNTAINS ETH1 Flat-Topped Seamounts ETH2 Anomalous Oceanic Plateaus ETH3 Mountain Curiosities ETL PLANET-SCALE TOPOGRAPHIC ANOMALIES ETL1 Land-Water Distribution ETL2 Anomalies of Island Arcs ETL3 Patterns of Lineaments ETL4 Relative Velocities of Continents ETL5 Indications of an Expanding Earth ETL6 Continental Fits -- Good and Bad ETL7 Topographical Anomalies and Continental Drift ETM MOUNDS AND HILLS ETM1 Mima Mounds ETM2 Mounds in ...
Terms matched: 1 - Score: 24 - 15 May 2017 - URL: /cat-geol.htm
... Science Frontiers ONLINE No. 31: Jan-Feb 1984 Issue Contents Other pages Home Page Science Frontiers Online All 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 ...
Terms matched: 1 - Score: 15 - 15 May 2017 - URL: /sf031/sf031p11.htm
... Science Frontiers ONLINE No. 52: Jul-Aug 1987 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Do large meteors/comets come in cycles?Only a few years ago, geologists refused to recognize any terrestrial meteor craters larger than Arizona's Meteor Crater, which is merely a mile or so in diameter. Now, we have a long list of craters or astroblemes (star wounds), some of which measure hundreds of miles across. In fact, there are enough large dated crters so that some scientists have taken up a time-honored human pastime: Looking for cycles or periodicities in the data. (Humans can find cyclicities in almost any collection of data!) To be more specific, some have claimed that large meteor craters come in clusters dated 28-31 million years apart. These catastrophic events have been correlated with biological extinctions, magnetic field reversals, and basalt flooding. The astronomical causes of this supposed periodicity range from the solar-system's crossing of the galactic plane, to the perturbations of an unseen solar companion, to regular perturbations of the Oort cloud of comets that is thought to hover at the fringe of the solar system. In short, a large, interlocking edifice of geological and astronomical speculation has been erected upon a foundation of terrestrial crater ages. But how well do we really know the ages of these craters? How complete is the cratering record? The answer to the first question is: "Not well at all." Further, we can be certain that many ...
Terms matched: 1 - Score: 15 - 15 May 2017 - URL: /sf052/sf052g13.htm
... Science Frontiers ONLINE No. 43: Jan-Feb 1986 Other pages Home Page Science Frontiers Online All Issues Last Issue Next Issue Sourcebook Project Sourcebook Subjects Contents Archaeology The Mysterious Tumuli of New Caledonia How Old is the Los Lunas Inscription? A Japanese Presence in Ancient Mexico? Astronomy Waiting for Saturn's Rings to Collapse Anomalous Distribution of Large, Fresh Lunar Craters The Planets As Fragments of An Ancient Companion of the Sun A Recent Transformation of Sirius? Biology & Geology The Return of the Tasmanian Tiger Life Seeks Out Energy Sources Wherever They May Be The Biological Diversity Crisis Treasures in A Toxonomic Wastebasket Piscatorial Data Processing Exploring the Suberranean World of Life The Cretaceous Incineration Everglades Astrobleme? Geophysics Underground Weather 1500-pound Ice Chunk Falls From Sky Psychology The Voice of God Chemistry & Physics "And So on Infinitum" The Thorny Way of Truth: Part II ...
Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf043/index.htm
... 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. Corliss ...
Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf043/sf043p14.htm
