Mineralogical, chemical, and isotopic analyses of clay minerals from outcrops and playa sediments, as well as chemical and isotopic analyses of groundwater and interstitial playa pore waters, have been used to improve ...

Using high-resolution, triplicate body waveforms, I investigate strong lateral variations in P- and SH-wave speeds (VP and VS) beneath the Tonga subduction zone where cold lithosphere is subducting rapidly at 200 mn/yr. ...

For the continental collision zone, I show that due to high VP near the bottom of the mantle transition zone, the contrast in VP across the 660-km discontinuity beneath central Tibet is small (around 3.1%): only about 70% ...

In the second part of this study, I developed the chromium stable isotope system as a biogeochemical indicator and monitoring tool. After initial work designing the techniques, I measured chromium stable isotope fractionation ...