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Posted on 08/11/2010 5:32:45 AM PDT by decimon
New Haven, Conn. — The Gondwana supercontinent underwent a 60-degree rotation across Earth’s surface during the Early Cambrian period, according to new evidence uncovered by a team of Yale University geologists. Gondwana made up the southern half of Pangaea, the giant supercontinent that constituted the Earth’s landmass before it broke up into the separate continents we see today. The study, which appears in the August issue of the journal Geology, has implications for the environmental conditions that existed at a crucial period in Earth’s evolutionary history called the Cambrian explosion, when most of the major groups of complex animals rapidly appeared.
The team studied the paleomagnetic record of the Amadeus Basin in central Australia, which was part of the Gondwana precursor supercontinent. Based on the directions of the ancient rock’s magnetization, they discovered that the entire Gondwana landmass underwent a rapid 60-degree rotational shift, with some regions attaining a speed of at least 16 (+12/-8) cm/year, about 525 million years ago. By comparison, the fastest shifts we see today are at speeds of about four cm/year.
This was the first large-scale rotation that Gondwana underwent after forming, said Ross Mitchell, a Yale graduate student and author of the study. The shift could either be the result of plate tectonics (the individual motion of continental plates with respect to one another) or “true polar wander,” in which the Earth’s solid land mass (down to the liquid outer core almost 3,000 km deep) rotates together with respect to the planet’s rotational axis, changing the location of the geographic poles, Mitchell said.
The debate about the role of true polar wander versus plate tectonics in defining the motions of Earth’s continents has been going on in the scientific community for decades, as more and more evidence is gathered, Mitchell said.
In this case, Mitchell and his team suggest that the rates of Gondwana’s motion exceed those of “normal” plate tectonics as derived from the record of the past few hundred million years. “If true polar wander caused the shift, that makes sense. If the shift was due to plate tectonics, we’d have to come up with some pretty novel explanations.”
Whatever the cause, the massive shift had some major consequences. As a result of the rotation, the area that is now Brazil would have rapidly moved from close to the southern pole toward the tropics. Such large movements of landmass would have affected environmental factors such as carbon concentrations and ocean levels, Mitchell said.
“There were dramatic environmental changes taking place during the Early Cambrian, right at the same time as Gondwana was undergoing this massive shift,” he said. “Apart from our understanding of plate tectonics and true polar wander, this could have had huge implications for the Cambrian explosion of animal life at that time.”
Other authors of the paper include David Evans and Taylor Kilian.
Citation: DOI: 10.1130/G30910.1
PRESS CONTACT: Suzanne Taylor Muzzin 203-432-8555
Junk science.
Thanks for your input, professor. Perhaps you’d like to detail the shortcomings of the research in question. I’m looking forward to hearing you explain why this is “junk science”, and why the positions you advocate go further in explaining the data.
The earth is about 8000 miles thick. The deepest we have drilled is about 8 miles. We don't really even know what's in the earth's core.
Plate tectonics theory was developed about 100 years ago (probably while Wegener was sitting in an outhouse.)
There may be a lot of good science used to develop the theory but the overall theory doesn't make sense.
Remember, last year you were a flat-earther if you denied AGW. In 1998, you were a fool if you thought the ever expanding universe was speeding up.
Seriously? A comic book artist? I tried to read the gibberish you provided, and while the author seems to have grasped some very basic principles of plate tectonics, other geomorphological concepts like, um, erosion, are ignored - forget about isostatic rebound, accreted terranes, or hot spots. I did watch one of the videos, and I’ve got to admit, it was pretty slick - too bad he pulled the “facts” out of his ass.
You are correct, we have not directly observed the Earth’s core. Our concept is admittedly speculation, but it is based on observation and the application of scientific principles and how they relate to the data, i.e. the characteristics of wave as they pass through different media and the nature of electromagnetic fields.
Wegener did not develop tectonic theory - he hypothesized about continental drift (his observations were later used in in the development of tectonic theory), and he did so in 1915 while recovering from injuries as a patient in a German military hospital.
As far as tectonic theory not “making sense”, what are the weaknesses? (and please don’t quote cartoonist Neal Adams) How does modern tectonic theory fail to describe the data in the most parsimonious manner?
Don't forget,
In 1970 we were going into an ice age. Now it's warming up.
In 1998 scientists believed the universe was expanding and slowing down. Now it's speeding up.
Barry Marshall cured stomach cancer because he didn't accept settled science.
I won't pretend to be a world class scientist, but I can read and think.
Interesting. I lived in the PNW at the time of that quake, but was on a layover in SFO. I was downtown Burlingame when the quake hit. Reminded me of when I lived in Alaska.
The PNW is certainly not immune to big earth quakes. And with the saturated ground, I’d want to be standing on rock when one hits.
Interesting. I lived in the PNW at the time of that quake, but was on a layover in SFO. I was downtown Burlingame when the quake hit. Reminded me of when I lived in Alaska.
The PNW is certainly not immune to big earth quakes. And with the saturated ground, I’d want to be standing on rock when one hits.
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...the Moon clearly could not have been the satellite of the Earth then, for a total period of about 2,000 million years... Spurr points out that the face of the Moon shows two systems of great surface fractures, or faults, lying about 30 degrees from the two poles and trending from west-south-west to east-north-east. This is explained by him as a result of the halting of the Moon's rotation... Curiously, the face of the Earth, too, shows a similar structure, with the same general trend -- the Highland Boundary Fault... The poles of the Earth would also seem to have shifted place on at least three occasions, in the Cambrian, Permian, and (lastly) Quaternary Periods, brining ice and cold to previously warm lands... some mighty force made the crust of the Earth slip (the rotational stability of the axis of a mass as large as the Earth is enormous) and the position of the poles wobbled... there exists on the Moon a triple grid of surface fractures... perpendicular to each other within each grid, the grids being of different ages... Cambrian, Perm-Carboniferous, and Tertiary.Firsoff's basically given us a snapshot of the problems inherent with a fission origin (having settled on an overspin origin for the Moon, very early in the history of the Earth), not least of which is that the fission origin also requires in orbit formation of the lunar sphere and capture by the Earth, while showing that capture is possible. Capture of the Moon, irrespective of its place and era of formation, is the simplest model.
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Thanks decimon. |
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...to some scientists...Rocks show life began 1bn years earlier than first thoughtScientists studying Australian rocks have found evidence that primitive forms of life existed 2.7bn years ago - a billion years earlier than had been previously shown... The finding pushes back evidence of life to the Archean era, the period from the beginning of earth to about 2.5bn years ago... Most rocks as old as the ones studied have undergone a process called metamorphism, an intense geological heating that changes them and which scientists believed would destroy any organic compounds they contained. But the shales studied by this team were well-preserved and still contained the biological chemicals. The researchers found evidence of organic compounds called lipids in the sedimentary rocks located more than 2,100ft deep in north-western Australia's Roy Hill Shale and Marra Mamba Formations. The rocks formed a seabed 2.6 bn to 2.7 bn years ago... Because of their complexity, eukaryotes were thought to have developed relatively late in earth's history. This discovery pushes the date for their appearance back to the earliest part of geological time.
The Guardian
Saturday August 14, 1999
[orig: www.newsunlimited.co.uk/uk_news/story/0,3604,73745,00.html]Paleoproterozoic snowball Earth (pdf)This snowball model predicts that postglacial, greenhouse-induced warming would lead to the deposition of banded iron formations and cap carbonates. Although global glaciation would have drastically curtailed biological productivity, melting of the oceanic ice would also have induced a cyanobacterial bloom, leading to an oxygen spike in the euphotic zone and to the oxidative precipitation of iron and manganese... Kirschvink noted that the extreme geochemical environments predicted by a snowball Earth model explain the Neo-proterozoic banded iron formations (BIFs).
Joseph L. Kirschvink et al
Early life theory takes a biffMoreover, the carbon isotopic basis used for interpreting its organic origin is questionable, the authors say. The authors demonstrate that much of the fine layering in the banded rocks, interpreted as a typical BIF (Banded Iron Formation) sedimentary structure, was in fact formed as a result of metamorphic processes.
May 24, 2002
A chemical study of the rocks also points away from a BIF origin for the banded rock. Analyses of green bands show that their composition is very similar to komatiite, a type of basalt. If this is correct there is little chance that the preserved graphite represents past life.
Recent studies of hydrothermal vents on mid-ocean ridges have also shown that basalt-like rocks can interact with water to form carbon compounds by non-biological processes, leaving an isotopic signature similar to that of metabolic function. While it is possible life existed on Earth when the rocks on Akilia formed, direct evidence for life older than approximately 3.8 billion years ago is still lacking.
"It's like no cheese I've ever tasted."
I believe that the fission theory still seems dominant. Myself, I have problems with the capture theory, maybe because I was lousy at catching baseballs or footballs.
Just ignore the troll.
Yes! I was just going to say that.
You saved me a whole bunch of typing!!!!!!
The only way to solve this problem is through peace and unity. Give heaps of money to Golden Sacks, Algore and his UN pals and they will be able to halt the drift and unite the globe!
Nice topic, SC. But this thread has descended into just plain silliness. I’m L-ingOL!
Reunite Gondwanaland indeed. *Snort*
I’m sure that it will be scientifically confirmed lunar or later.
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