[meteorite-list] Deep Inside an Impact Crater Lake in Siberia

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 17 Nov 2006 09:03:25 -0800 (PST)
Message-ID: <200611171703.JAA21540_at_zagami.jpl.nasa.gov>

http://www.livescience.com/imageoftheday/siod_061117.html

Deep Inside a Lake
LiveScience.com
November 17, 2006

A team of scientists will embark on an expedition to a polar lake in
Siberia, which should yield data that will provide the most detailed
record of past Arctic climate to date.

Understanding the natural climatic variations of the Arctic - such as
which aspects are cyclic and which are stable - will illuminate how the
region evolved from a warm ecosystem blanketed in forest to a cold one
covered in permafrost. And ultimately it could give scientists a glimpse
at the Arctic of tomorrow, the researchers say.

The destination is Lake El'gygytgyn, a lake of roughly nine miles across
that was formed when a meteorite hurtled into northeastern Siberia
around 3.6 million years ago. Unlike much of the Arctic, this lake was
never covered by glaciers or ice sheets and thus has received a steady
accumulation of sediment since the time of impact. Scientists will
collect deep cores of this sediment - cylindrical columns of dense muck
that should provide a detailed narrative of the past climate of the Arctic.

Once the cores are extracted, the assemblage of pollen grains, algae and
bacteria within the sediment will tell the scientists what was living in
and around the lake throughout its history. The researchers will also
read the cores for changes in geochemistry, the magnetic orientation of
the muck's minerals and other parameters that capture what happened to
the Arctic's climate since the time of impact. These data will be
compared with cores taken from the north Atlantic and Pacific oceans, as
well as tropical oceans, allowing scientists to address climate change
questions on a broad scale.
Received on Fri 17 Nov 2006 12:03:25 PM PST