Tuesday, December 15, 2009

AGU 2009: Day 1

Hello everyone!

The AGU Fall Meeting 2009 began yesterday at the Moscone Convention Center in San Francisco, California. Thousands of geoscientists have been roaming the halls of the two buildings housing the conference, going to talks, seeing posters, or discussing their research in the halls.

AGU also has had a series of 'town hall' meetings on various issues; one of them was about communicating with Congress, and the content of the meeting was reproduced in a fantastic cartoon board for everyone to see.

Since I am studying paleoclimate for my master's thesis (Owens Lake core OL-92, lake sediment geochemistry), I attended a lot of talks about climate yesterday. There are many good records of paleoclimate that scientists use to tease out the mechanics of the climate system: lake records, stalactites/stalagmites ('speleothems'), sedimentary rocks, marine microfossils (foraminifera, radiolarians, etc.), and much more.

Dr. Fawcett of the University of New Mexico gave a talk about a new lake record from the Valles Caldera, northern NM. This lake record is very detailed; parts of the core are laminated (creating a lake texture called a 'varve') and capture a very short amount of time in each layer, a 'snapshot' of what the lake (and climate) was like at a particular point in time. Laminated sediments look like stripes in a sediment core (a long cylindrical mass of sediment extracted from a lake); when you see stripes, you know that it has been disturbed very little (burrowing clams and snails mix up a lot of sediment, in a process called 'bioturbation') and thus you have a good chance of taking samples of each thin lamina, which you can process geochemically to find proxies for paleoclimate. One of the geochemical proxies we look at is total organic carbon (TOC), which is an indicator of how much life was supported by the lake; changes in TOC might indicate the availability of nutrients for life in the lake, which is affected by changing rainfall over time -climate! The core from Valles Caldera will shed light on climate 360,000 to 560,000 years ago, and tell us how it varied over time.

Thanks for your time, and look for more updates later today or tomorrow!


Cassy Meyers

No comments:

Post a Comment