Start Surface exposure dating

Surface exposure dating

This work was done in collaboration with Julie Libarkin at Ohio University.

These cosmic rays do not penetrate deep into the earth’s surface.

However cosmogenic He dating of additional minerals which are known to retain He at Earth surface conditions, especially the common accessory phases apatite, sphene, and zircon.

The challenge of working with these minerals is their small grain size, which causes a variety of nuclear effects associated with the long stopping range of He in the accessory phases separated from a tuff in Bolivia.

Surface exposure dating provides critical information on a range of Earth science problems including ages of glacial features, erosion rates, and rates of fault motion.

The technique relies on the production of rare isotopes produced by interactions of cosmic rays with target nuclei in rocks within ~ 1 meter of Earth's surface.

The exposure ages of the Indus Valley moraines are the oldest observed to date throughout the Himalayan orogen.

We observe a pattern of progressively more restricted glaciation during the last five glacial cycles, likely indicating a progressive reduction in the moisture supply necessary to sustain glaciation.

Spallation reactions occur in minerals in the rocks upon bombardment by cosmic rays.