New York Tsunami 300 BCE

This is a neat story that likely got little coverage outside New York, if there. It does tell us that meteorite strikes should not be discounted as sources of tsunami events.

That alone is useful. Tsunami events are mapable in the sedimentary record. Event markers can be checked for. Local impact tsunami events can be sorted out. This report tells geologists to question unusual sediments exposed to tsunami events for an impact signature.

Any crater here, if it could be pinpointed, is likely to be quite close by.

I hope that this means that this particular unique event was never replicated over the past ten thousand years. We presume the 1159 BC Hekla event came from the wrong direction and strength to leave any sign not long since eroded away.

It actually is a good measure of how often a particular stretch of coast line might be impacted by a significant meteor generated tsunami. The risk is real though very small and in the modern era we have some semblance of warning and possible response.

http://www.nytimes.com/2008/12/30/nyregion/30tsunami.html

Meteorite Strikes, Setting Off a Tsunami: Did It Happen Here?

By KENNETH CHANG

Published: December 29, 2008

The tsunami washed over Fire Island and, to the west, waves perhaps as high as 20 feet spilled into Lower Manhattan. The furious onrush of water left sediment a foot and a half deep on the Jersey Shore, and debris cascaded far up the Hudson River.

A Columbia scientist has reported finding carbon spheres, above, in sediment, indicating a meteorite.

No, there’s no need to rush to higher ground, commandeer a rowboat in Central Park or empty the closet to grab the rubber boots. This disaster occurred about 2,300 years ago, though how bad it was, or even if it was a tsunami, remains in dispute.

But several geologists have collected evidence indicating that something very big and unusual occurred in waters near the New York area around 300 B.C., give or take a century. And Dallas Abbott, a research scientist at Columbia University’s Lamont-Doherty Earth Observatory, is asserting that a meteorite, landing somewhere in the Atlantic, generated the tsunami.

Someone at the tip of Lower Manhattan then would probably have seen “something coming in,” Dr. Abbott said. “Then you would hear a big bang, maybe a series of bangs, something that sounded like gunfire or cannons. It would be a really, really loud noise. And then you would be knocked to the ground by the air blast. And then you would be inundated by the tsunami.”

While not nearly as severe as the tsunami that killed more than 180,000 people in South and Southeast Asia in 2004, “it would have been a bad day to end all bad days,” she said, “in all senses.”

Although American Indians had long been living in and around the area that became New York, Dr. Abbott said there was no archeological evidence of a tsunami or known legends of, say, a terrible flood. She has built her case with diamonds, very tiny ones.

At a meeting of the American Geophysical Union in San Francisco earlier this month, Dr. Abbott reported finding minute carbon spheres and smaller-than-dust diamonds in sediment layers, which she said were the distinctive calling cards of a meteorite’s impact.

“I think it’s pretty convincing,” Dr. Abbott said. “We always find the impact ejecta in the tsunami layer, never outside.”

A few years ago, the geologist Steven Goodbred, then at the State University of New York at Stony Brook, was not looking for tsunamis or meteorites when he first examined sediment cores taken along the South Shore of Long Island. Dr. Goodbred was interested in the history of oysters in that area. But in the very first core, he saw a strange layer several inches thick containing fist-size gravel.

“We started joking immediately, ‘It’s a tsunami,’ ” recalled Dr. Goodbred, now a professor at Vanderbilt University in Nashville.

Subsequent cores, taken in Great South Bay, also contained that layer, deposited about 2,300 years ago. When Dr. Goodbred presented his findings at a conference a couple of years ago, he failed to convince other scientists. They said the layer was more likely caused by a big storm, not a tsunami.

“Even if it was a storm, it was the mother of all storms,” Dr. Goodbred said, pointing out that the devastating hurricane that passed directly over Long Island in 1938 generated less than an inch of sediment.

Then Dr. Goodbred met other scientists who had found similar sediment layers nearby. Cecilia McHugh, a professor at Queens College, had seen a sediment layer a foot and a half thick at Sandy Hook in New Jersey. That, too, was laid down about 2,300 years ago. And Frank Nitsche, another research scientist at Lamont-Doherty, had discovered a layer of wood debris in sediment cores from the upstate reaches of the Hudson River.

Then Dr. Abbott joined the project and found possible evidence of a meteorite.

But the arguments of a meteor causing a New York tsunami are still regarded skeptically by many, if not most, geologists. For one, no one has found any craters.

The evidence hinges most strongly on the tiny diamonds, presumably formed by the ultra-high pressures of impact.

The carbon atoms inside some of the diamonds are lined up in a hexagonal crystal structure instead of the usual cubic crystals. The hexagonal diamonds have been found only within meteorites and at impact craters, said Allen West, a geologist who performed the diamond analysis for Dr. Abbott’s New York sediments.

But unless researchers find a crater in the ocean floor, an Indian legend telling of a day of fire and water or many more thick sediment deposits, convincing other scientists of what they believe happened 2,300 years ago will continue to be an uphill battle.

Earth's Magnetic Field

This article is a nice summary of the present state of our ideas about the Earth’s interior and its magnetic engine. To be totally fair, it is complete rubbish to think in terms of swirling dynamos. The core is packed and any motion must be glacial at best. Electron flow is quite a different matter. But even that requires a meaningful potential. And we already know that the mere movement of the magnetic field itself rules out the core acting like a permanent magnet.

An actual review of the global map of magnetic strength reveals a non homogenous field that still preserves the polar orientation. Sort of.

I have come to the conclusion that there exists a thin layer of (liquid) carbon between the crustal material which is disassociating and drawing contained graphitic carbon down with it before hitting the carbon melt point and then rising. The carbon must go deepest to reach a possible melt point. Or perhaps it is all graphite. The point to remember is that all other elements are dissociated there and in liquid state.

This explains how a charge of liquid carbon is able to spear its way through the crust and even reaches the surface at around seventy miles per hour. That is also fast enough to leave a little of the carbon to remain in crystal form. The rest will be consumed by the crustal material itself. Recall the known low viscosity of graphite.

This layer may only be a hundred feet thick if the average size of a kimberlite pipe is an indicator. It is certainly everywhere and about eighty miles deep. It is the slip plane between the crust and the core itself and the reason why any crustal movement is even possible at all.

The mere existence of kimberlite pipes and diamonds is proof of the existence of this layer of pure liquid carbon.

It is also a great place for storing electrons and a natural generator of a strong magnetic field that can shift and move in reaction to modest electrical or even mechanical stimulation. It likely insulates the core itself from expressing magnetic activity.

Earth's Core, Magnetic Field Changing Fast, Study Says

Kimberly Johnson

for National Geographic News June 30, 2008 Rapid changes in the churning movement of Earth's liquid outer core are weakening the magnetic field in some regions of the planet's surface, a new study says.

"What is so surprising is that rapid, almost sudden, changes take place in the Earth's magnetic field," said study co-author Nils Olsen, a geophysicist at the Danish National Space Center in Copenhagen.

The findings suggest similarly quick changes are simultaneously occurring in the liquid metal, 1,900 miles (3,000 kilometers) below the surface, he said.

The swirling flow of molten iron and nickel around Earth's solid center triggers an electrical current, which generates the planet's magnetic field.

The study, published recently in Nature Geoscience, modeled Earth's magnetic field using nine years of highly accurate satellite data.

Flip-Flop

Fluctuations in the magnetic field have occurred in several far-flung regions of Earth, the researchers found.

In 2003 scientists found pronounced changes in the magnetic field in the Australasian region. In 2004, however, the changes were focused on Southern Africa.

The changes "may suggest the possibility of an upcoming reversal of the geomagnetic field," said study co-author Mioara Mandea, a scientist at the German Research Centre for Geosciences in Potsdam.

Earth's magnetic field has reversed hundreds of times over the past billion years and the process could take thousands of years to complete.

(Related story: "Magnetic Field Weakening in Stages, Old Ships' Logs Suggest" [May 11, 2006])

Upper Atmosphere Radiation

The decline in the magnetic field also is opening Earth's upper atmosphere to intense charged particle radiation, scientists say.

Satellite data show the geomagnetic field decreasing in the South Atlantic region, Mandea said, adding that an oval-shaped area east of Brazil is significantly weaker than similar latitudes in other parts of the world.

"It is in this region that the shielding effect of the magnetic field is severely reduced, thus allowing high energy particles of the hard radiation belt to penetrate deep into the upper atmosphere to altitudes below a hundred kilometers (62 miles)," Mandea said.

This radiation does not influence temperatures on Earth. The particles, however, do affect technical and radio equipment and can damage electronic equipment on satellites and airplanes, Olsen of the Danish space center said.

Keep Watching

The study documents just how rapidly the flow in Earth's core is changing, said Peter Olson, a geophysics professor at Johns Hopkins University in Baltimore, Maryland, who was not involved with the research.

By using satellite imagery, researchers have a nearly continuous measurement of changes, he said.

"They provide a good rationale to continue this monitoring longer," Olson said.

Pleistocene Nonconformity - 5 - Crustal slipperiness

We now tackle the question of how the crust might be able to move at all. Recall that it was this objection more that anything else that doomed Wegener's hypothesis to obscurity for decades. Our evidence for a crustal shift is similar to his evidence for continental drift. That is, it is obvious to any school boy looking at a globe and following up on a little deduction once the key idea is picked up on.

Crustal slipperiness

The recognition of the reality of plate tectonics is one of the great triumphs of modern earth science. It has created order out of geological chaos and has hugely informed our understanding of all geological processes. In particular, mountain building can be seen as momentum discharge as one crustal plate crashes into another.

The catch is that the movement of the plates, which is measurable and ongoing, represents a serious energy puzzle. Practically, if we reasonably assume that the affected crust is approximately one hundred miles thick, then a one hundred mile wide section, lifted about one vertical mile by underlying fluid pressure and continuously replaced, generates enough force to push a one hundred mile thick plate continuously. Obviously, this could only happen if the underlying friction is negligible. Certainly global hydrostatic energy transmission is inferred and we can additionally infer movement along a low-viscosity fluidic boundary layer in the direction of plate travel. This is still not good enough since crustal integrity will generate overlaps into areas of counter flow. We quickly return to a situation in which it would be nice to see low friction along the crustal slip plane.

That we are dealing with a slip plane is nicely demonstrated by the passing of the Pacific plate over the apparent Hawaiian hot spot. I observe that if the Pleistocene crustal movement hypothesis is correct, then this particular hot spot has been shifted and will take a massive amount of time to re emerge. In the meantime the molten zones developed beneath the main island will continue to expel material. The vast majority of geologically active zones including plate consumption are contained within the crust and these are simply carried along by any crustal movement. The hot spot is an exception.

The absolute need for low viscosity is apparent. We observe that the deepest rocks we encounter on the surface are the Kimberlites, which rocket to the surface from the one hundred-mile depth associated with the deepest basement of the crust. The implied speed of travel of an estimated seventy-five miles per hour infers remarkable fluidity. More importantly, the source temperature and pressure eliminates all but the most chemically bound compounds. In other words, there is no water or other gases migrating to higher levels in the crust.

Perhaps we should take our cue from the Kimberlites, which are the primary host for diamonds. The diamonds precipitate out from pure carbon within the Kimberlites as they rocket to the surface. What is often forgotten is that the Kimberlites are rapidly shedding carbon all the way to the surface. This implies that the rock began as a fluid supersaturated in carbon. The fact that diamond crystals are formed at all presupposes a supersaturated solution. My speculation is that the crustal layer including the Asthenosphere lies on a layer of material supersaturated in pure carbon, thicker than previously supposed that is inherently slippery and having low viscosity. It seems unlikely that at these pressures, that the slipperiness of graphite is retained, but that may well be the case.

One feature of carbon that is often overlooked is its high melt temperature compared to other elements. It becomes molten at temperatures in excess of 3500^o C. It boils at temperatures over 4000^o C. Of the common elements and minerals entrained in the crust, carbon resists melting the longest. Add this to the fact of its low density as compared to these same materials and we have the necessary conditions for a concentration plane for carbon under the crust. Convection above would send non-molten carbon down into the carbon layer and convection below this layer would concentrate this layer by density. The Kimberlites merely confirm it.

The existence of this layer possibly answers another interesting problem. The implied high natural electrical conductivity of this layer makes it an excellent candidate for handling the massive global electron flow necessary to electrically affect the global magnetic field. The electron flow itself can be physically derived from the daily solar and lunar tides that will cyclically stress and relax the layer, inducing a steady build up of static charge and inducing electron flow within the conductive layer. The zone of maximum charging would be concentrated within belts paralleling the equator with the electron flow possibly either flowing towards the poles or flowing primarily along the equator following the tides.

We can certainly postulate a charging shell. The complexity of the tidal effect resulting from the twenty-three degree tilt of the globe prevents an easy configuration of the electron flow. This shell charging process needs to be cumulative over geological time periods until the process itself must discharge the buildup of electrical energy. The most certain way to do this would be to force the reversal of the earth’s magnetic field. This has in fact occurred often. This process is clearly benign and any shifts will be abrupt. They may even become predictable.

I do not have an exact electromagnetic model to describe this possible behavior pattern, and it may well turn out to be theoretically impossible. The only simple model that occurs to me is one in which the electron flow is nudged along by the daily tides until the electron wave is large enough to collapse and reverse itself jolting the magnetic field into a reversal. Thereupon the flow is reestablished against the new magnetic field and is built up to the point that it once again forces a pole shift draining off some of the accumulated energy. Then once again it builds up and strengthens the magnetic field until the wave once again collapse. This seems possible. On the other hand, I rather think the explanation will prove much more sophisticated.

Right now we simply do not know and any theoretical models will be difficult to prove.

Returning to the subject of crustal movement the possibility of extreme slipperiness does partially open the door to the possibility of the crust been much more mobile than has been reasonably expected. This needs to be investigated thoroughly on a theoretical basis. There may be subtle forms of dynamic instability that are built up by the application of tidal stress and released by floating the crust to a new orientation.

In any event, we have one mechanism in place by the high velocity high-density asteroid that is capable of generating the movements without obliterating all life. It also enables polar shifting as a result of the buildup of the polar ice caps as a second option which would be even more survivable.

We now come to the compelling part of this tale. That is the data itself. Quite bluntly, rotating the crust along the proscribed axis makes a large number of major difficulties with the currently held paradigm disappear. More importantly, the solution seems to be global, as it must. My natural concern is for this type of event to be anomalous and extraterrestrial in origins. A recurring earth based cyclic event would be a catastrophe for the future of our own civilization.