This
adds an important new factor in our understanding of the dynamics of
global climate change. The core factor is simply Continental
geometry. I suspect we need to run multiple climate runs over a huge
range of possible variations just to perfect our own knowledge there.
After
all if my conjecture regarding crustal Shift holds up as it should,
there will have been a whole range of climatic changes commencing
13,000 years ago. These could be predicted and then confirmed by
field work.
More
importance it would be a powerful way to learn much more about our
own climate itself. It would certainly end the hysterical aspect of
much climate prognostication.
In
the meantime here we discover that the impact of India against Asia
produced a non geometric factor that altered ocean chemistry and may
have been repeated in the past also. It is good enough to explain
the divergence of Eocene climate, yet another unanswered question for
those that are counting.
Ancient Alteration
of Seawater Chemistry Linked With Past Climate Change
by Staff Writers
Washington DC (SPX) Jul 26, 2012
Scientists
have discovered a potential cause of Earth's "icehouse
climate" cooling trend of the past 45 million years. It has
everything to do with the chemistry of theworld's oceans.
"Seawater chemistry is characterized by long phases of
stability, which are interrupted by short intervals of rapid change,"
says geoscientist Ulrich Wortmann of the University of Toronto, lead
author of a paper reporting the results and published this week in
the journal Science.
"We've
established a new framework that helps us better interpret
evolutionary trends and climate change over long periods of time. The
study focuses on the past 130 million years, but similar interactions
have likely occurred through the past 500 million years."
Wortmann and co-author
Adina Paytan of the University of California Santa Cruz point to the
collision between India and Eurasia approximately 50 million years
ago as one example of an interval of rapid change.
This collision
enhanced dissolution of the most extensive belt of water-soluble
gypsum on Earth, stretching from Oman to Pakistan and well into
western India. Remnants of the collision are exposed in the Zagros
Mountains in western Iran.
The dissolution or
creation of such massive gypsum deposits changes the sulfate content
of the ocean, say the scientists, affecting the amount of sulfate
aerosols in the atmosphere and thus climate.
"We propose that
times of high sulfate concentrations in ocean water correlate with
global cooling, just as times of low concentrations correspond
with greenhouse [warmer] periods," says Paytan.
"When India and
Eurasia collided, it caused dissolution of ancient salt deposits,
which resulted in drastic changes in seawater chemistry."
That may have led to
the end of the Eocene epoch--the warmest period of the modern-day
Cenozoic era--and the transition from a greenhouse to an icehouse
climate. "It culminated in the beginning of the rapid
expansion of the Antarctic ice sheet," says Paytan.[
I do not buy that because it it is more plausible that Ice Caps are
driven by the arrival of land inside the 15 degree window around the
pole itself ]
Canada's Natural
Sciences and Engineering Research Council supports Wortmann's
research and the U.S. National Science Foundation (NSF) supports
Paytan research.
"Abrupt changes
in seawater composition are a new twist in our understanding of the
links among ocean chemistry, plate tectonics, climate and evolution,"
says Candace Major, program director in NSF's Division of Ocean
Sciences.
To make the discovery,
the researchers combined past seawater sulfur composition data
collected by Paytan with Wortmann's recent discovery of the strong
link between marine sulfate concentrations and carbon and phosphorus
cycling.
They found that
seawater sulfate reflects huge changes in the accumulation and
weathering of gypsum, which is the mineral form of hydrated calcium
sulfate.
"While it's been
known for a long time that gypsum deposits can be formed and
destroyed rapidly, the effect of these processes on seawater
chemistry has been overlooked," says Wortmann.
"The idea
represents a paradigm shift in our understanding of how ocean
chemistry changes over time, and how these changes are linked with
climate."
Data
used in the research were collected aboard the ocean drillship JOIDES
Resolution and through the Integrated Ocean Drilling Program
(IODP).
The
JOIDES Resolution is a scientific research vessel managed by the U.S.
Implementing Organization of IODP. Texas A and M University,
Lamont-Doherty Earth Observatory of Columbia University and the
Consortium for Ocean Leadership comprise the implementing
organization. Two lead agencies support the IODP: the U.S. NSF and
Japan's Ministry of Education, Culture, Sports, Science and
Technology. Additional program support comes from the European
Consortium for Ocean Research Drilling, the Australia-New Zealand
IODP Consortium, India's Ministry of Earth Sciences, the
People's Republic of China's Ministry of Science and Technology, and
the Korea Institute of Geoscience and Mineral Resources.
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