Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere

Romain A. Bouchet, Janne Blichert-Toft, Mary Reid, Alan Levander, Francis Albarède

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

In order to elucidate the nature and history of the different geological units in the western USA and correlate geochemical signatures with features identified in seismic models developed from USArray, we compiled from the literature Pb isotope compositions of ores, granitic K-feldspars, and felsic plutonic rocks and complemented the database by analyzing Pb isotopes for 82 felsic xenoliths and plutonic rocks from the Colorado Plateau and its immediate vicinity. The raw Pb isotope abundances for the complete data set were converted into model ages T (time of last U/Pb fractionation), 238U/204Pb (μ), and 232Th/238U (κ) with computed representative values for grid cells of 1° × 1°. The model ages reflect the old formation ages in the Mojave and Yavapai blocks and the Archean Wyoming craton. Model ages are reset wherever the Moho is relatively shallow, most notably west of the Rocky Mountains, likely as a result of metamorphic reheating ± melting above the Pb closure temperature (~550-650°C). The κ values correlate with the uppermost mantle VP/VS ratio. High κ values are found in the Snake River basin and central Colorado. High κ values also form a ridge trending south from northwestern Utah through the Great Basin into the Mojave and Yavapai blocks. This ridge may represent exhumation of deep-seated rocks as a result of regional extension and collapse. Alternatively, it may signal the presence of igneous and metamorphic material associated with a channel of flowing crust originating beneath the Colorado Plateau and spreading north.

Original languageEnglish (US)
Pages (from-to)243-254
Number of pages12
JournalEarth and Planetary Science Letters
Volume391
DOIs
StatePublished - Apr 1 2014

Fingerprint

seismic property
basements
lithosphere
Colorado Plateau (US)
Isotopes
Crystalline materials
isotopes
felsic rock
Rocks
plutonic rock
isotope
rocks
ridges
Great Basin (US)
Rocky Mountains (North America)
plateau
river basins
closure temperature
feldspars
cratons

Keywords

  • Continental crust
  • Lead isotopes
  • Receiver functions
  • Seismology
  • Western USA

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere. / Bouchet, Romain A.; Blichert-Toft, Janne; Reid, Mary; Levander, Alan; Albarède, Francis.

In: Earth and Planetary Science Letters, Vol. 391, 01.04.2014, p. 243-254.

Research output: Contribution to journalArticle

Bouchet, Romain A. ; Blichert-Toft, Janne ; Reid, Mary ; Levander, Alan ; Albarède, Francis. / Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere. In: Earth and Planetary Science Letters. 2014 ; Vol. 391. pp. 243-254.
@article{d7f7efe4476f4a97a0e6685ccb15b595,
title = "Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere",
abstract = "In order to elucidate the nature and history of the different geological units in the western USA and correlate geochemical signatures with features identified in seismic models developed from USArray, we compiled from the literature Pb isotope compositions of ores, granitic K-feldspars, and felsic plutonic rocks and complemented the database by analyzing Pb isotopes for 82 felsic xenoliths and plutonic rocks from the Colorado Plateau and its immediate vicinity. The raw Pb isotope abundances for the complete data set were converted into model ages T (time of last U/Pb fractionation), 238U/204Pb (μ), and 232Th/238U (κ) with computed representative values for grid cells of 1° × 1°. The model ages reflect the old formation ages in the Mojave and Yavapai blocks and the Archean Wyoming craton. Model ages are reset wherever the Moho is relatively shallow, most notably west of the Rocky Mountains, likely as a result of metamorphic reheating ± melting above the Pb closure temperature (~550-650°C). The κ values correlate with the uppermost mantle VP/VS ratio. High κ values are found in the Snake River basin and central Colorado. High κ values also form a ridge trending south from northwestern Utah through the Great Basin into the Mojave and Yavapai blocks. This ridge may represent exhumation of deep-seated rocks as a result of regional extension and collapse. Alternatively, it may signal the presence of igneous and metamorphic material associated with a channel of flowing crust originating beneath the Colorado Plateau and spreading north.",
keywords = "Continental crust, Lead isotopes, Receiver functions, Seismology, Western USA",
author = "Bouchet, {Romain A.} and Janne Blichert-Toft and Mary Reid and Alan Levander and Francis Albar{\`e}de",
year = "2014",
month = "4",
day = "1",
doi = "10.1016/j.epsl.2014.02.004",
language = "English (US)",
volume = "391",
pages = "243--254",
journal = "Earth and Planetary Sciences Letters",
issn = "0012-821X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere

AU - Bouchet, Romain A.

AU - Blichert-Toft, Janne

AU - Reid, Mary

AU - Levander, Alan

AU - Albarède, Francis

PY - 2014/4/1

Y1 - 2014/4/1

N2 - In order to elucidate the nature and history of the different geological units in the western USA and correlate geochemical signatures with features identified in seismic models developed from USArray, we compiled from the literature Pb isotope compositions of ores, granitic K-feldspars, and felsic plutonic rocks and complemented the database by analyzing Pb isotopes for 82 felsic xenoliths and plutonic rocks from the Colorado Plateau and its immediate vicinity. The raw Pb isotope abundances for the complete data set were converted into model ages T (time of last U/Pb fractionation), 238U/204Pb (μ), and 232Th/238U (κ) with computed representative values for grid cells of 1° × 1°. The model ages reflect the old formation ages in the Mojave and Yavapai blocks and the Archean Wyoming craton. Model ages are reset wherever the Moho is relatively shallow, most notably west of the Rocky Mountains, likely as a result of metamorphic reheating ± melting above the Pb closure temperature (~550-650°C). The κ values correlate with the uppermost mantle VP/VS ratio. High κ values are found in the Snake River basin and central Colorado. High κ values also form a ridge trending south from northwestern Utah through the Great Basin into the Mojave and Yavapai blocks. This ridge may represent exhumation of deep-seated rocks as a result of regional extension and collapse. Alternatively, it may signal the presence of igneous and metamorphic material associated with a channel of flowing crust originating beneath the Colorado Plateau and spreading north.

AB - In order to elucidate the nature and history of the different geological units in the western USA and correlate geochemical signatures with features identified in seismic models developed from USArray, we compiled from the literature Pb isotope compositions of ores, granitic K-feldspars, and felsic plutonic rocks and complemented the database by analyzing Pb isotopes for 82 felsic xenoliths and plutonic rocks from the Colorado Plateau and its immediate vicinity. The raw Pb isotope abundances for the complete data set were converted into model ages T (time of last U/Pb fractionation), 238U/204Pb (μ), and 232Th/238U (κ) with computed representative values for grid cells of 1° × 1°. The model ages reflect the old formation ages in the Mojave and Yavapai blocks and the Archean Wyoming craton. Model ages are reset wherever the Moho is relatively shallow, most notably west of the Rocky Mountains, likely as a result of metamorphic reheating ± melting above the Pb closure temperature (~550-650°C). The κ values correlate with the uppermost mantle VP/VS ratio. High κ values are found in the Snake River basin and central Colorado. High κ values also form a ridge trending south from northwestern Utah through the Great Basin into the Mojave and Yavapai blocks. This ridge may represent exhumation of deep-seated rocks as a result of regional extension and collapse. Alternatively, it may signal the presence of igneous and metamorphic material associated with a channel of flowing crust originating beneath the Colorado Plateau and spreading north.

KW - Continental crust

KW - Lead isotopes

KW - Receiver functions

KW - Seismology

KW - Western USA

UR - http://www.scopus.com/inward/record.url?scp=84894025376&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84894025376&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2014.02.004

DO - 10.1016/j.epsl.2014.02.004

M3 - Article

AN - SCOPUS:84894025376

VL - 391

SP - 243

EP - 254

JO - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

ER -