Petroleum geologists have known for some time that reserves beneath the Gulf of Mexico were once part of the continent. They know, too, that for whatever reason cavities developed in the oceanic crust that allowed the oil to flow from the mainland down into these voids beneath the ocean. They have been aware that during orogenic events and eruptions along the mid-oceanic ridge, the floor of the ocean may fall, leading to sea level regression. Scientists have also known that asteroid impacts of 100km or more are sometimes followed by a dramatic drop in sea level which results in mass extinctions.
A few years ago, the entire southeast was searched for any remaining petroleum reserves, but the search was unsuccessful. There had been reason for optimism, though, for along the Alabama-Florida line a series of "subsistence" zones were located. Another was found in southwest Georgia. These areas commonly have sinkhole development and have been linked to small earthquakes, but more importantly, are sometimes found near off-shore oil reserves.
Now, though, it seems probable that they are there because of empty voids in the earth's crust collapsing over time. Voids that were created during the rush of molten material form beneath the oceanic crust into the breach made by the astrobleme as the sea floor sank as petroleum ran downhill into them.
In actuality, the sinking of the sea floor and subsequent drop in sea level together with the collection of petroleum within the sea floor crust were not the cause of the extinction but rather symptomatic of the much larger event.
Perhaps one of the best ways to gauge this astroblemic event is too take a closer look at the fossil record and the lack thereof.
While southwest Alabama beyond the Fall Line Hills boasts of some of the finest Cretaceous fossils ever found and farther up near Tuscaloosa dinosaur remains are regularly found, it is an entirely different story east of these sandy hills. Although shark's teeth and sea shells are found near the rim, large vertebrate fossils of the Cretaceous Period do not exist within the astrobleme except small fragments.
The real story lies in fossilized trees which covered the landscape as living plants at the time of impact. Those nearest the center were blown apart while whole forests were laid down and buried away from ground zero. Beneath the deep sand of Fall Line Hills that comprise the southwest section of the astrobleme's rim lie whole forests that are perfectly preserved. Fossils of trees are plentiful inside the crater because they were not rock at the time and fossilization came after the fact.
Heratite is found in abundance throughout the southeast in every condition imaginable from very small pieces to very large ones. Sometimes magnetite is also found but has not been linked to any impact as of yet.
Other evidence found in Alabama includes clay spherules containing K-T glass, shocked quartz and micro-tekites. These were not addressed in this piece.
See
Comments: The information presented in this website is intended to both inform the reader by presenting the evidence I have collected and try to explore the correlation I noticed. Other people may have a different view, but I cordially invite their input.
Harold Clinton Gragg, Geological Research Author
E-mail Address: alimpact2@bellsouth.net
| Introduction/Main | The Sylacauga Astrobleme | Photographs | Conclusion |
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