[1] Sp and Ps converted seismic waves at 93 permanent seismic stations are used to image upper mantle velocity discontinuities across the contiguous United States and portions of southeast Canada and northwest Mexico. Receiver functions are calculated with frequency‐ domain deconvolution and migrated with 1D models that account for variations in crustal structure and mantle velocities between s...

Several chromite deposits located in the in the South and Southeast Arms of Sulawesi, Indonesia, have been investigated by electron microprobe. According to the variation of the Cr# = Cr/(Cr + Fe3+), the chromite composition varies from Cr-rich to Al-rich. Small platinum-group minerals (PGM), 1–10 μm in size, occur in the chromitites. The most abundant PGM is laurite, which has been found inclu...

The Australian Seismological Reference Model (AuSREM) represents a state-of-the-art geophysical synthesis of the continent. To date, its shear-wave component has limited resolution at lower-crustal to uppermost-mantle depths, where it is mainly constrained by sparse measurements collected local scale. In this study, we compile large data set surface-wave phase velocities based on seismic ambien...

Abstract Properties of the lithosphere control transitions in elevation and plate deformation from hot, mobile orogenic belts to cooler, stronger cratons. The sharp, abrupt boundary North American Cordillera with craton western Canada has been suggested be a result recent (<50 Ma) heating delamination lithosphere. To test this, we queried fine structure thermal history mantle approaching...

ABSTRACT What causes previously stable continental crust in the forelands of Cordilleran orogenic systems to shorten during low-angle subduction? The National Science Foundation/EarthScope Bighorn Project combined seismic imaging and Moho with kinematic modeling Laramide (Late Cretaceous–Paleogene) basement-involved deformation address this question. In north-central Wyoming, asymmetrical ENE-v...

SUMMARY As recovering the crust–mantle/Moho density contrast (MDC) significantly depends on properties of Earth's crust and upper mantle, varying from place to place, it is an oversimplification define a constant standard value for it. It especially challenging in Antarctica, where almost all bedrock covered with thick layer ice, seismic data cannot provide sufficient spatial resolution geologi...

S U M M A R Y The structure of the oceanic crust conforms in general to a very simple model. However, fine-scale variations of this structure in anomalous regions (such as beneath oceanic islands) remain poorly resolved. Here we examine teleseismic receiver functions (RFs) computed at four permanent broadband seismic stations on islands in the Pacific region. The RF method is ideal for examinin...

The Tien Shan and its adjacent areas have been a prime place to understand the process of continental collision, mechanism mountain building interaction tectonic blocks. In this study, we collect seismic data recorded by 74 broad-band stations from China Provincial Digital Seismic Networks Regional Kyrgyzstan Kazakhstan between January, 2007 September, 2009. A joint inversion technique that com...