Wednesday, July 27, 2011
"Atlantis-Like" submerged Landscape Nr Scotland Discovered (Internet News Item)
....A Lost World? Atlantis-Like Landscape Discovered
[Map, Geology of Scotland-DD]
By Wynne Parry
LiveScience.com LiveScience.com – Sun, Jul 10, 2011
Buried deep beneath the sediment of the North Atlantic Ocean lies an ancient, lost landscape with furrows cut by rivers and peaks that once belonged to mountains. Geologists recently discovered this roughly 56-million-year-old landscape using data gathered for oil companies.
"It looks for all the world like a map of a bit of a country onshore," said Nicky White, the senior researcher. "It is like an ancient fossil landscape preserved 2 kilometers (1.2 miles) beneath the seabed."
So far, the data have revealed a landscape about 3,861 square miles (10,000 square km) west of the Orkney-Shetland Islands that stretched above sea level by almost as much as 0.6 miles (1 km). White and colleagues suspect it is part of a larger region that merged with what is now Scotland and may have extended toward Norway in a hot, prehuman world.
History beneath the seafloor
The discovery emerged from data collected by a seismic contracting company using an advanced echo-sounding technique. High pressured air is released from metal cylinders, producing sound waves that travel to the ocean floor and beneath it, through layers of sediment. Every time these sound waves encounter a change in the material through which they are traveling, say, from mudstone to sandstone, an echo bounces back. Microphones trailing behind the ship on cables record these echoes, and the information they contain can be used to construct three-dimensional images of the sedimentary rock below, explained White, a geologist at the University of Cambridge in Britain.
The team, led by Ross Hartley, a graduate student at the University of Cambridge, found a wrinkly layer 1.2 miles (2 km) beneath the seafloor — evidence of the buried landscape, reminiscent of the mythical lost Atlantis.
The researchers traced eight major rivers, and core samples, taken from the rock beneath the ocean floor, revealed pollen and coal, evidence of land-dwelling life. But above and below these deposits, they found evidence of a marine environment, including tiny fossils, indicating the land rose above the sea and then subsided — "like a terrestrial sandwich with marine bread," White said.
The burning scientific question, according to White, is what made this landscape rise up, then subside within 2.5 million years? "From a geological perspective, that is a very short period of time," he said.
The giant hot ripple
He and colleagues have a theory pointing to an upwelling of material through the Earth's mantle beneath the North Atlantic Ocean called the Icelandic Plume. (The plume is centered under Iceland.)
The plume works like a pipe carrying hot magma from deep within the Earth to right below the surface, where it spreads out like a giant mushroom, according to White. Sometimes the material is unusually hot, and it spreads out in a giant hot ripple.
The researchers believe that such a giant hot ripple pushed the lost landscape above the North Atlantic, then as the ripple passed, the land fell back beneath the ocean.
This theory is supported by other new research showing that the chemical composition of rocks in the V-shaped ridges on the ocean floor around Iceland contains a record of hot magma surges like this one. Although this study, led by Heather Poore, also one of White's students, looked back only about 30 million years, White said he is hopeful ongoing research will pinpoint an older ridge that recorded this particular hot ripple.
Because similar processes have occurred elsewhere on the planet, there are likely many other lost landscapes like this one. Since this study was completed, the researchers have found two more recent, but less spectacular, submerged landscapes above the first one, White said.
Both studies appear today (July 10) in the journal Nature Geoscience.
[-It is often stated that the Mid-Ocean ridges are expanding because of upwelling plumes of magma such as the one described here. What is NOT often noted is that the magma chamber that should be in the middle of the North Atlantic is not there. The Chamber has blown out, and quite recently and signs are from the surrounding lanscape that the ridge has subsided to a depth of 6000 to 9000 feet, at least. Several recent articles mention this, but N. Zhirov already had much evidence of the collapsed Mid-Atlantic ridge back when he wrote his book on Atlantis. A review of this book follows]
Crustal Magma Chambers
Melted material migrates upward from the mantle to form the oceanic crust. When cooled sufficiently from above, this melt will pond and form a liquid pool or magma chamber. Cracking of overlying rock will open conduits (usually axis-parallel planar dikes) to feed extrusive basalt flows at the seafloor. Whether a magma chamber is usually present beneath the seafloor is thought to be strongly dependent on spreading rate. On the fast spreading East Pacific Rise there is extensive evidence from multichannel seismic studies for an axial magma chamber. This is thought to be a steady state feature, found on 60% of the ridge between the Siqueiros Fracture Zone at 8°30'N and 13°30'N. Its width across axis is 1-1.5 km and height 100-500 m. The low velocity zone surrounding this body is thought to be material with at least 3% melt. In contrast there is no evidence of the existence of persistent magma chambers on the Mid-Atlantic Ridge,[Emph added-DD] although such bodies are [thought to be] likely present episodically.
[On this cross-section of the Mid-Pacific rise there is a mantle plume arising to approx 4 km depth and a ridge with a domed profile. The Atlantic ridge does not have the same profile when the plume is taken away and there may well be a slump down to 4km depth in its place-DD]
Atlantis: Atlantology - Basic Problems
By N. Zhirov, Review on Amazon.com
Paperback: 444 pages
Publisher: Univ Pr of the Pacific (September 2001)
Product Dimensions: 8.8 x 6 x 1.3 inches
A Soviet scientist examines geology, climate, oceanography and attempts reconstruction of Atlantis. Illustrated with maps, charts, tables, illustrations, seismic data, sonar images, etc.
The fascinating age-old riddle of the legendary continent of Atlantis is a challenge to any investigator for it would be hard to name a problem of longer standing or one that has given rise to sharper controversies and differences of views and opinions. Some investigators have rejected it as a key to an ancient riddle throwing light on many aspects of human history and civilization. Thousands of books and papers have been devoted to the thrilling problem of Atlantis, and a new scientific trend, atlantology, studying Atlantis has emerged.
Atlantology cannot advance without the aid of geomorphology and marine geology, which are relatively new spheres of human knowledge. Indeed, the problems linked up with Atlantis can be approached successfully only by drawing upon the latest achievements of world science in the study of the geological structure and relief of the ocean bed, only in the light of the new ideas about the youth and active development of oceans.
The author believes that Atlantis existed [As an island in the Nortth Atlantic which sank at the end of the Ice Age-DD] and uses a great number of facts to back up his arguments. His work sums up much on what we know about atlantology. This book will unquestionably serve as the basis for elaborating on many aspects of one of the world’s most dramatic problems. Zhirov was a chemist by trade and a leading Soviet Atlantologist. The book was written between 1959-63. New data was added for this English edition. Seismics, gravimetrics, climatology, paleobotanical data, geomorphology, plate tectonics, turbidity data, bottom current patterns, submarine erosion and geological data separate this book from most of the rest of the Atlantology field. Cites 825 separate sources in 34 pages of references - Russian, Ukrainian, Greek, German, English, Latin....
Zhirov's book is far and away the best single source on Atlantis from the standpoint of truly Scientific evidence. It is a must-read for any serious researcher-Dale D.