Many commonly used shallow seismic sources are unacceptable for hazardous waste site investigations because they risk exhumation of contaminants in the soil, they add contaminants (e.g. lead) which are not allowed by regulations, or they add new migration paths for contaminants. Furthermore, recently developed high frequency vibrators for shallow investigations could be more effective at some s...

Proterozoic rocks of the southwestern United States exhibit a variety of tectonometamorphic histories that can all be explained by a characteristic looping style of pressure-temperature (P-T) path. The path is fundamentally clockwise. However, because the rocks were cooled isobarically at 3 kbar after tectonism, the cooling path crosses the prograde path, leading to a geometry with a counterclo...

We describe a model of crustal deformation and thermal structure across the Nepal Himalaya over the last 20Myr. The model assumes that, throughout this period, shortening across the range has been entirely taken up by slip along a single thrust fault, the Main Himalayan Thrust (MHT) Fault, and that the growth of the Himalayan wedge has resulted from the development of a duplex at mid-crustal sc...

Metapelites collected in central Nepal reveal a discontinuity in metamorphic pressuretemperature-time (P-T-t) paths near the base of the Main Central thrust zone, despite an absence of obvious structural breaks. Garnets in the structurally lowest rocks grew with increasing T and P (loading), whereas garnets 1–3 km upsection grew with increasing T, but decreasing P (exhumation). Monazite grains ...

New SHRIMP and TIMS zircon ages, Ar=Ar ages, and eclogite locations contribute significantly to our understanding of the ultrahigh-pressure Dabie Shan. (1) The geographic extent of the Yangtze craton that was subducted to ultrahigh pressure extends to the northern edge of the Dabie Shan. (2) The northern half of the Dabie Shan is a magmatic complex, intruded over a 10-Myr interval between 137 a...

Erosion of orogenic mountain ranges exhumes deeply buried rocks and controls weathering, climate, and sediment production and transport at a variety of scales. Erosion also affects the topographic form and kinematics of orogens, and it may provide dynamic feedbacks between climate and tectonics by spatially focused erosion and rock uplift. Thermochronology measures the timing and rates at which...