Nature of the lower crust and moho in eastern Nevada from “wide‐angle” reflection measurements

Paul A. Valasek, Robert B. Hawman, Roy A Johnson, Scott B. Smithson

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Wide angle recordings at offsets between 20 and 40 km in the Ruby Mountains consistently show 5 strong reflections between 4 and 11 s with enough moveout to estimate velocities to the base of the crust. The uppermost “layer” with a temperature corrected velocity of 6.2 km/s and thickness of 9 km corresponds to quartzofeldspathic rocks such as metasedimentary rocks, migmatites and deformed granites and is underlain by a 7‐km‐thick “layer” with velocities of 6.4 km/s which corresponds to quartzofeldspathic material interlayered with amphibolites. The lower crust consists of a heterogeneous, 9 km‐thick zone with velocities of 6.7 to 6.8 km/s corresponding to mafic rocks interlayered with smaller amounts of quartzofeldspathic rock. The lowermost crust is marked by the “X” reflection overlying a 3‐km‐thick “layer” with velocities between 7.4‐7.8 km/s corresponding to anomolous material, possibly layered cumulates. The subhorizontal, layered structure of the crust is caused primarily by ductile extension, which may well be superposed on material added to the crust by underplating. At most, approximately one third of the present crust could have been added by underplating in the Cenozoic.

Original languageEnglish (US)
Pages (from-to)1111-1114
Number of pages4
JournalGeophysical Research Letters
Volume14
Issue number11
DOIs
StatePublished - 1987
Externally publishedYes

Fingerprint

Moho
lower crust
crusts
crust
rocks
underplating
ruby
metasedimentary rock
cumulate
mafic rock
rock
mountains
recording
mountain
material
estimates
temperature

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Nature of the lower crust and moho in eastern Nevada from “wide‐angle” reflection measurements. / Valasek, Paul A.; Hawman, Robert B.; Johnson, Roy A; Smithson, Scott B.

In: Geophysical Research Letters, Vol. 14, No. 11, 1987, p. 1111-1114.

Research output: Contribution to journalArticle

Valasek, Paul A. ; Hawman, Robert B. ; Johnson, Roy A ; Smithson, Scott B. / Nature of the lower crust and moho in eastern Nevada from “wide‐angle” reflection measurements. In: Geophysical Research Letters. 1987 ; Vol. 14, No. 11. pp. 1111-1114.
@article{fdb39bed97f140378cd9f0ec7bf2ff51,
title = "Nature of the lower crust and moho in eastern Nevada from “wide‐angle” reflection measurements",
abstract = "Wide angle recordings at offsets between 20 and 40 km in the Ruby Mountains consistently show 5 strong reflections between 4 and 11 s with enough moveout to estimate velocities to the base of the crust. The uppermost “layer” with a temperature corrected velocity of 6.2 km/s and thickness of 9 km corresponds to quartzofeldspathic rocks such as metasedimentary rocks, migmatites and deformed granites and is underlain by a 7‐km‐thick “layer” with velocities of 6.4 km/s which corresponds to quartzofeldspathic material interlayered with amphibolites. The lower crust consists of a heterogeneous, 9 km‐thick zone with velocities of 6.7 to 6.8 km/s corresponding to mafic rocks interlayered with smaller amounts of quartzofeldspathic rock. The lowermost crust is marked by the “X” reflection overlying a 3‐km‐thick “layer” with velocities between 7.4‐7.8 km/s corresponding to anomolous material, possibly layered cumulates. The subhorizontal, layered structure of the crust is caused primarily by ductile extension, which may well be superposed on material added to the crust by underplating. At most, approximately one third of the present crust could have been added by underplating in the Cenozoic.",
author = "Valasek, {Paul A.} and Hawman, {Robert B.} and Johnson, {Roy A} and Smithson, {Scott B.}",
year = "1987",
doi = "10.1029/GL014i011p01111",
language = "English (US)",
volume = "14",
pages = "1111--1114",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "11",

}

TY - JOUR

T1 - Nature of the lower crust and moho in eastern Nevada from “wide‐angle” reflection measurements

AU - Valasek, Paul A.

AU - Hawman, Robert B.

AU - Johnson, Roy A

AU - Smithson, Scott B.

PY - 1987

Y1 - 1987

N2 - Wide angle recordings at offsets between 20 and 40 km in the Ruby Mountains consistently show 5 strong reflections between 4 and 11 s with enough moveout to estimate velocities to the base of the crust. The uppermost “layer” with a temperature corrected velocity of 6.2 km/s and thickness of 9 km corresponds to quartzofeldspathic rocks such as metasedimentary rocks, migmatites and deformed granites and is underlain by a 7‐km‐thick “layer” with velocities of 6.4 km/s which corresponds to quartzofeldspathic material interlayered with amphibolites. The lower crust consists of a heterogeneous, 9 km‐thick zone with velocities of 6.7 to 6.8 km/s corresponding to mafic rocks interlayered with smaller amounts of quartzofeldspathic rock. The lowermost crust is marked by the “X” reflection overlying a 3‐km‐thick “layer” with velocities between 7.4‐7.8 km/s corresponding to anomolous material, possibly layered cumulates. The subhorizontal, layered structure of the crust is caused primarily by ductile extension, which may well be superposed on material added to the crust by underplating. At most, approximately one third of the present crust could have been added by underplating in the Cenozoic.

AB - Wide angle recordings at offsets between 20 and 40 km in the Ruby Mountains consistently show 5 strong reflections between 4 and 11 s with enough moveout to estimate velocities to the base of the crust. The uppermost “layer” with a temperature corrected velocity of 6.2 km/s and thickness of 9 km corresponds to quartzofeldspathic rocks such as metasedimentary rocks, migmatites and deformed granites and is underlain by a 7‐km‐thick “layer” with velocities of 6.4 km/s which corresponds to quartzofeldspathic material interlayered with amphibolites. The lower crust consists of a heterogeneous, 9 km‐thick zone with velocities of 6.7 to 6.8 km/s corresponding to mafic rocks interlayered with smaller amounts of quartzofeldspathic rock. The lowermost crust is marked by the “X” reflection overlying a 3‐km‐thick “layer” with velocities between 7.4‐7.8 km/s corresponding to anomolous material, possibly layered cumulates. The subhorizontal, layered structure of the crust is caused primarily by ductile extension, which may well be superposed on material added to the crust by underplating. At most, approximately one third of the present crust could have been added by underplating in the Cenozoic.

UR - http://www.scopus.com/inward/record.url?scp=84989535729&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84989535729&partnerID=8YFLogxK

U2 - 10.1029/GL014i011p01111

DO - 10.1029/GL014i011p01111

M3 - Article

AN - SCOPUS:84989535729

VL - 14

SP - 1111

EP - 1114

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 11

ER -