Seismic evidence for lithospheric foundering beneath the southern Transantarctic Mountains, Antarctica

Document Type

Article

Department or Administrative Unit

Geological Sciences

Publication Date

11-29-2017

Abstract

The 3000-km-long Transantarctic Mountains (TAMs), which separate cratonic East Antarctica from tectonically active West Antarctica, remain one of the least understood of Earth’s major mountain ranges. The tectonic mechanism that generates the high elevation, as well as the processes that produce major differences between various sectors of the TAMs, are still uncertain. Here we present newly constructed seismic images of the crust and uppermost mantle beneath central Antarctica derived from recently acquired seismic data, indicating ongoing lithospheric foundering beneath the southern TAMs. These images reveal an absence of thick, cold cratonic lithosphere beneath the southern TAMs. Instead, an uppermost-mantle slow seismic anomaly extends across the mountain front and 350 km into East Antarctica, beneath a high plateau near the South Pole. Under the slow anomaly, a relatively high-wave-speed root is found at ∼200 km depth, connected with the East Antarctic lithosphere, suggesting that sinking lithosphere has been replaced at shallow depths by warm, slow-velocity asthenosphere. A mantle lithosphere foundering model is proposed to interpret these images, which best explains the present large area of high elevation and the uplift of the TAMs, as well as Miocene-age volcanism in the Mount Early region.

Comments

This article was originally published in Geology. The full-text article from the publisher can be found here.

Due to copyright restrictions, this article is not available for free download from ScholarWorks @ CWU.

Journal

Geology

Rights

© 2017 Geological Society of America.

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