Monday, May 30, 2022

Articles: Earthquake Temperatures, Marshes, Ocean Drilling

Sharing some good stuff I came across recently.

1) Taking the temperature of faults. From AGU News. Rocks get hot as they slide past each other during faulting. Chemical changes in organic molecules and helium content in zircon crystals are sensitive to temperature changes. Scientists have used these to estimate short lived temperature rise during faulting. Understanding patterns and magnitude of earthquake generated heat informs us about earthquake intensity, heat dissipation, and fault movement history. 

2) Why a Marsh: "Neither land nor water, maybe both, a marsh is a balancing act, a collaboration between changing elements, uncertain by its very nature, in flux"

A beautiful long essay by Daniel Wolff and Dorothy Peteet on marshes and wetlands and the vital role they play in ecosystem functioning. Especially fascinating is the description of Piermont Marsh, along the banks of the Hudson river, north of New York City. Sediment cores going back a thousand years preserve a record of climate change and human modification of the landscape. The marsh was first exploited by Native Americans and then more extensively by European settlers. It is a detailed look at the wealth of information a wetland can yield about climate, ecology, and human disturbance of the environment.

3) Drilling Into the Sea Bed: This is a really interesting summary of scientific ocean drilling by Neena Notman . They are attempts going on to reach the earth's mantle by drilling into the sea bed. Although drilling in the deep ocean seems daunting, this makes more sense than trying to reach the mantle from land. The crust making up the continents is much thicker. Ocean bed drilling offers a short cut to the earth's mantle. We know about the mantle mostly through geophysical data. Actual samples of the mantle are rare. Recovering pristine pieces of the mantle will allow us to validate what we've gleaned from geophysics. Drilling is also going on along a subduction zone to understand the nature of fault interface and rock properties.


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