The southern Sierra Nevada drip and the mantle wind direction beneath the southwestern United States

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The Miocene-Pliocene convective removal of the southern Sierra Nevada batholithic root and its sinking through the upper mantle provides a natural experiment to estimate the direction and velocity of mantle flow beneath the southwestern United States. Xenolith data, volcanism patterns, and geologic evidence are used to constrain the location and timing of the initial detachment. Seismic tomography images of the upper mantle are used to determine the displacement of the downwelling "tail" by the background mantle flow. The "mantle wind" direction based on this analysis is estimated to be SSW, in contradiction to another recent estimate based on a combination of geodetic data and shear-wave splitting measurements. The conflicting conclusions can be reconciled if the splitting measurements are dominated by anisotropy in the shallow mantle imposed by lithospheric motion. The SSW direction is approximately consistent with global models of asthenospheric counterflow directions, and therefore supports the idea that self-driving plate forces can explain the absolute motion of the North American plate.

Original languageEnglish (US)
Pages (from-to)213-224
Number of pages12
JournalInternational Geology Review
Volume45
Issue number3
StatePublished - Mar 2003

Fingerprint

wind direction
mantle
upper mantle
North American plate
geodetic datum
wave splitting
xenolith
seismic tomography
downwelling
S-wave
volcanism
Pliocene
anisotropy
Miocene
experiment

ASJC Scopus subject areas

  • Geology

Cite this

The southern Sierra Nevada drip and the mantle wind direction beneath the southwestern United States. / Zandt, George.

In: International Geology Review, Vol. 45, No. 3, 03.2003, p. 213-224.

Research output: Contribution to journalArticle

@article{c2e9504f8a474904be53d1f1cff02907,
title = "The southern Sierra Nevada drip and the mantle wind direction beneath the southwestern United States",
abstract = "The Miocene-Pliocene convective removal of the southern Sierra Nevada batholithic root and its sinking through the upper mantle provides a natural experiment to estimate the direction and velocity of mantle flow beneath the southwestern United States. Xenolith data, volcanism patterns, and geologic evidence are used to constrain the location and timing of the initial detachment. Seismic tomography images of the upper mantle are used to determine the displacement of the downwelling {"}tail{"} by the background mantle flow. The {"}mantle wind{"} direction based on this analysis is estimated to be SSW, in contradiction to another recent estimate based on a combination of geodetic data and shear-wave splitting measurements. The conflicting conclusions can be reconciled if the splitting measurements are dominated by anisotropy in the shallow mantle imposed by lithospheric motion. The SSW direction is approximately consistent with global models of asthenospheric counterflow directions, and therefore supports the idea that self-driving plate forces can explain the absolute motion of the North American plate.",
author = "George Zandt",
year = "2003",
month = "3",
language = "English (US)",
volume = "45",
pages = "213--224",
journal = "International Geology Review",
issn = "0020-6814",
publisher = "Bellwether Publishing, Ltd.",
number = "3",

}

TY - JOUR

T1 - The southern Sierra Nevada drip and the mantle wind direction beneath the southwestern United States

AU - Zandt, George

PY - 2003/3

Y1 - 2003/3

N2 - The Miocene-Pliocene convective removal of the southern Sierra Nevada batholithic root and its sinking through the upper mantle provides a natural experiment to estimate the direction and velocity of mantle flow beneath the southwestern United States. Xenolith data, volcanism patterns, and geologic evidence are used to constrain the location and timing of the initial detachment. Seismic tomography images of the upper mantle are used to determine the displacement of the downwelling "tail" by the background mantle flow. The "mantle wind" direction based on this analysis is estimated to be SSW, in contradiction to another recent estimate based on a combination of geodetic data and shear-wave splitting measurements. The conflicting conclusions can be reconciled if the splitting measurements are dominated by anisotropy in the shallow mantle imposed by lithospheric motion. The SSW direction is approximately consistent with global models of asthenospheric counterflow directions, and therefore supports the idea that self-driving plate forces can explain the absolute motion of the North American plate.

AB - The Miocene-Pliocene convective removal of the southern Sierra Nevada batholithic root and its sinking through the upper mantle provides a natural experiment to estimate the direction and velocity of mantle flow beneath the southwestern United States. Xenolith data, volcanism patterns, and geologic evidence are used to constrain the location and timing of the initial detachment. Seismic tomography images of the upper mantle are used to determine the displacement of the downwelling "tail" by the background mantle flow. The "mantle wind" direction based on this analysis is estimated to be SSW, in contradiction to another recent estimate based on a combination of geodetic data and shear-wave splitting measurements. The conflicting conclusions can be reconciled if the splitting measurements are dominated by anisotropy in the shallow mantle imposed by lithospheric motion. The SSW direction is approximately consistent with global models of asthenospheric counterflow directions, and therefore supports the idea that self-driving plate forces can explain the absolute motion of the North American plate.

UR - http://www.scopus.com/inward/record.url?scp=0041887353&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0041887353&partnerID=8YFLogxK

M3 - Article

VL - 45

SP - 213

EP - 224

JO - International Geology Review

JF - International Geology Review

SN - 0020-6814

IS - 3

ER -