Foundered Lithospheric Segments Dropped into the Mantle Transition Zone Beneath Southern California, USA
The diverse range of active tectonics occurring in southern California, USA, offers an opportunity to explore processes of continental deformation and modification in response to the instability of the Pacific and Farallon plates. Here, we present a high-resolution receiverfunction image of the mantle transition zone (MTZ). Our result reveals significant lateral heterogeneities in the deep mantle beneath southern California. Both seismic tomography and MTZ discontinuity deflections reveal foundered lithospheric segments that have dropped into the MTZ beneath the western Transverse Ranges, the Peninsular Ranges, and part of the southern Sierra Nevada. Water dehydrated from these foundered materials may contribute to the observed MTZ thickening. Our observations, combined with previous tomography and geochemical results, indicate that lithospheric foundering of fossil arc roots provides a way for geochemical heterogeneities to be recycled into the underlying mantle, and suggest that the foundered materials can play a significant role in inducing lateral variations of MTZ structure.
Y. Yu et al., "Foundered Lithospheric Segments Dropped into the Mantle Transition Zone Beneath Southern California, USA," Geology, vol. 48, no. 2, pp. 200-204, Geological Society of America (GSA), Feb 2020.
The definitive version is available at https://doi.org/10.1130/G46889.1
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Seismology, Continental deformation; Geochemical heterogeneity; Lateral heterogeneity; Lateral variations; Mantle transition zone; Seismic tomography; Southern California; Southern sierra nevada, Geochemistry, deflection; deformation; discontinuity; geochemistry; heterogeneity; image analysis; lithosphere; mantle; plate tectonics; seismic tomography, California; Coast Ranges; Peninsular Ranges; Sierra Nevada [California]; Transverse Ranges; United States
International Standard Serial Number (ISSN)
Article - Journal
© 2020 Geological Society of America (GSA), All rights reserved.
01 Feb 2020