Mantle discontinuity structure from midpoint stacks of converted P to S waves across the Yellowstone hotspot track

摘要: Analysis of a deployment broadband sensors along 500-km-long line crossing the Yellowstone hotspot track (YHT) has provided 423 in-plane receiver functions with which to image lateral variations in mantle discontinuity structure. Imaging is accomplished by performing converted wave equivalent common midpoint stack, significantly improves resolution structure respect single-station stacks. Timing corrections are calculated from locally derived tomographic P and S velocity images applied Pds (where d depth conversion) ray set order isolate true topography. Using one-dimensional TNA model Vp/Vs ratio 1.82 map our times depth, average depths 410- 660-km discontinuities 664 km, respectively, giving an transition zone thickness 241 km. Our most robust observation comparing stack all NW back-azimuth arrivals versus SE arrivals. This shows that varies between 261 232 portions line. More spatially resolved show this variation results occurrence 20–30 km topography over 200–300 scale lengths on discontinuities. The not correlated either positively or negatively beneath 600-km-long transect, albeit correlation could be present for wavelengths larger than length transect. If controlled exclusively thermal effects, then uncorrelated 250° temperature required at However, other sources such as effects garnet-pyroxene phase transformations, chemical layering, hydration may contribute. obvious downward dip 410-km 415 margin YHT 435 easternmost extent Basin Range faulting. Assuming thermally controlled, warmest resides track, but 150 edge active