Constraining the crustal composition of the continental U.S. using seismic observables

The composition of the crust is one most uncertain and controversial components continental estimates due to (1) limited direct access (2) inconsistent indirect assessments. Here we show that by combining high-resolution shear velocity (Vs) models with newly measured ratio compressional wave (Vp) Vs, or Vp/Vs ratio, for crystalline crust, a 3-D (SiO2 wt%) model can be derived uncertainty estimates. Comparing local xenolith data shows consistency at mid lower crustal depths. spatial patterns in bulk SiO2 content correlate major geological provinces, including footprints Cenozoic Mesozoic mafic volcanism western U.S., offer new insight into evolution U.S.