Compositional Zoning of the Bishop Tuff

Paleointensity estimates from ignimbrites: An evaluation of the Bishop Tuff

Evaluating the paleomagnetic potential of single zircon crystals using the Bishop Tuff

a Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA b Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA c Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA d Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA e Department of Physics, Harvard University, Cambridg...

Frequency Dependence of Attenuation in Ground-Penetrating Radar: Insights from the Bishop Tuff

Total attenuation in ground-penetrating radar (GPR) was directly measured in radargrams of the Bishop Tuff, CA, from 12.5–200 MHz. The weak variation of attenuation with frequency reaffirms the "GPR Plateau" concept and argues against a constant-Q model. Electrolytic absorption —determined using collocated DC resistivity profiling/ sounding—accounts for about half of the attenuation and is by d...

Systematic compositional zoning in the quaftz fibers of agates

Etched sections of agates examined by scanning electron microscopy show three types of compositional zonation'. (1) two-unit oscillatory sequences in which the successive zones are of the same width, on a micron scale, but show a uniform difference in the content of (OH) in structural sites; (2) three-unit oscillatory sequenc€s of various palindromic types in which successive zones are of the s...

Incremental heating of Bishop Tuff sanidine reveals preeruptive radiogenic Ar and rapid remobilization from cold storage.

Accurate and precise ages of large silicic eruptions are critical to calibrating the geologic timescale and gauging the tempo of changes in climate, biologic evolution, and magmatic processes throughout Earth history. The conventional approach to dating these eruptive products using the 40Ar/39Ar method is to fuse dozens of individual feldspar crystals. However, dispersion of fusion dates is co...