Subducted Lithosphere Under South America From Multifrequency <i>P</i> Wave Tomography
نویسندگان
چکیده
We analyze mantle structure under South America in the DETOX-P1 seismic tomography model, a global-scale, multifrequency inversion of teleseismic P waves. inverts most extensive data set broadband, waveform-based traveltime measurements to date, complemented by analyst-picked traveltimes from ISC-EHB catalog. The is sampled ?665,000 cross-correlation measured on 529 American broadband stations and 5,389 elsewhere. By their locations, depths, geometries, we distinguish four high-velocity provinces America, interpreted as subducted lithosphere (“slabs”). deepest (?1,800–1,200 km depth) shallowest (<600 km) slab are observed beneath Andean Cordillera near continent’s northwest coast. At intermediate depths (1,200–900 km, 900–600 km), two farther east, Brazil, Bolivia Venezuela, with links Caribbean. interpret slabs relative America’s paleo-position over time, exploring hypothesis that sank essentially vertically after widening viscous deformation transition zone. province carries geometric imprint continental margin represents ocean-beneath-continent subduction during Cenozoic times. deepest, farthest west complex formed intra-oceanic trenches late Jurassic Cretaceous times, far adjoined Africa. complexes record westward eastward America. This geophysical inference matches geologic records Jura-Cretaceous, extensional “intra-arc” basins basin onset modern arc ?85 Ma.
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ژورنال
عنوان ژورنال: Journal Of Geophysical Research: Solid Earth
سال: 2021
ISSN: ['2169-9356', '2169-9313']
DOI: https://doi.org/10.1029/2020jb020704