Synkinematic intrusion of the 1.4-Ga Boriana Canyon Pluton, northwestern Arizona: Implications for Ca. 1.4-Ga regional strain in the Western United States

Colin B. Ferguson, Ernest M Duebendorfer, Kevin R. Chamberlain

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The transcontinental belt of ca. 1.4-Ga granite plutons that extends from southern California to Labrador has conventionally been interpreted as either "anorogenic" or emplaced in an extensional tectonic setting. Recent studies in the western United States, however, demonstrate that several ca. 1.4-Ga plutons were emplaced in a broadly northwest-southeast shortening strain field. Our study of the 1404 + 1.5-Ma Boriana Canyon pluton, northwestern Arizona, establishes the emplacement age by U-Pb zircon analysis and reveals synintrusive deformation consistent with northwest-southeast shortening. The Boriana Canyon pluton contains northeast-striking mylonite zones that record reverse-sense, northwest-side-up motion. Undeformed late dikes crosscut solid-state deformation zones in the pluton, indicating synintrusive deformation. The mylonites also contain a continuum of microstructures that record high-temperature plastic deformation through low-temperature brittle deformation. This study adds to the growing catalog of ca. 1.4-Ga plutons deformed by synintrusive, broadly northwest-southeast shortening strains. Several studies, however, document shear zones with orientations that may not be strictly compatible with northwest-southeast shortening. Our results are consistent with models invoking a convergent or transpressive tectonic margin at the southern margin of Laurentia at ca. 1.4 Ga. Alternatively, however, we propose that the 1.4-Ga granites may have been emplaced into an ambient, generally compressional, intracontinental stress field in the absence of an active plate margin at the southern margin of Laurentia. An intracontinental stress field coupled with a large-scale thermal anomaly would allow local deviations from overall northwest-southeast shortening while still explaining why the majority of studied 1.4-Ga plutons record shortening strains.

Original languageEnglish (US)
Pages (from-to)165-183
Number of pages19
JournalJournal of Geology
Volume112
Issue number2
DOIs
StatePublished - Mar 2004

Fingerprint

canyon
pluton
Laurentia
stress field
mylonite
brittle deformation
extensional tectonics
plastic deformation
tectonic setting
temperature anomaly
shear zone
dike
microstructure
emplacement
zircon
granite
tectonics

ASJC Scopus subject areas

  • Geology

Cite this

Synkinematic intrusion of the 1.4-Ga Boriana Canyon Pluton, northwestern Arizona : Implications for Ca. 1.4-Ga regional strain in the Western United States. / Ferguson, Colin B.; Duebendorfer, Ernest M; Chamberlain, Kevin R.

In: Journal of Geology, Vol. 112, No. 2, 03.2004, p. 165-183.

Research output: Contribution to journalArticle

@article{1a8bf2e1e02146cebd11e75bbb8b0039,
title = "Synkinematic intrusion of the 1.4-Ga Boriana Canyon Pluton, northwestern Arizona: Implications for Ca. 1.4-Ga regional strain in the Western United States",
abstract = "The transcontinental belt of ca. 1.4-Ga granite plutons that extends from southern California to Labrador has conventionally been interpreted as either {"}anorogenic{"} or emplaced in an extensional tectonic setting. Recent studies in the western United States, however, demonstrate that several ca. 1.4-Ga plutons were emplaced in a broadly northwest-southeast shortening strain field. Our study of the 1404 + 1.5-Ma Boriana Canyon pluton, northwestern Arizona, establishes the emplacement age by U-Pb zircon analysis and reveals synintrusive deformation consistent with northwest-southeast shortening. The Boriana Canyon pluton contains northeast-striking mylonite zones that record reverse-sense, northwest-side-up motion. Undeformed late dikes crosscut solid-state deformation zones in the pluton, indicating synintrusive deformation. The mylonites also contain a continuum of microstructures that record high-temperature plastic deformation through low-temperature brittle deformation. This study adds to the growing catalog of ca. 1.4-Ga plutons deformed by synintrusive, broadly northwest-southeast shortening strains. Several studies, however, document shear zones with orientations that may not be strictly compatible with northwest-southeast shortening. Our results are consistent with models invoking a convergent or transpressive tectonic margin at the southern margin of Laurentia at ca. 1.4 Ga. Alternatively, however, we propose that the 1.4-Ga granites may have been emplaced into an ambient, generally compressional, intracontinental stress field in the absence of an active plate margin at the southern margin of Laurentia. An intracontinental stress field coupled with a large-scale thermal anomaly would allow local deviations from overall northwest-southeast shortening while still explaining why the majority of studied 1.4-Ga plutons record shortening strains.",
author = "Ferguson, {Colin B.} and Duebendorfer, {Ernest M} and Chamberlain, {Kevin R.}",
year = "2004",
month = "3",
doi = "10.1086/381656",
language = "English (US)",
volume = "112",
pages = "165--183",
journal = "Journal of Geology",
issn = "0022-1376",
publisher = "University of Chicago",
number = "2",

}

TY - JOUR

T1 - Synkinematic intrusion of the 1.4-Ga Boriana Canyon Pluton, northwestern Arizona

T2 - Implications for Ca. 1.4-Ga regional strain in the Western United States

AU - Ferguson, Colin B.

AU - Duebendorfer, Ernest M

AU - Chamberlain, Kevin R.

PY - 2004/3

Y1 - 2004/3

N2 - The transcontinental belt of ca. 1.4-Ga granite plutons that extends from southern California to Labrador has conventionally been interpreted as either "anorogenic" or emplaced in an extensional tectonic setting. Recent studies in the western United States, however, demonstrate that several ca. 1.4-Ga plutons were emplaced in a broadly northwest-southeast shortening strain field. Our study of the 1404 + 1.5-Ma Boriana Canyon pluton, northwestern Arizona, establishes the emplacement age by U-Pb zircon analysis and reveals synintrusive deformation consistent with northwest-southeast shortening. The Boriana Canyon pluton contains northeast-striking mylonite zones that record reverse-sense, northwest-side-up motion. Undeformed late dikes crosscut solid-state deformation zones in the pluton, indicating synintrusive deformation. The mylonites also contain a continuum of microstructures that record high-temperature plastic deformation through low-temperature brittle deformation. This study adds to the growing catalog of ca. 1.4-Ga plutons deformed by synintrusive, broadly northwest-southeast shortening strains. Several studies, however, document shear zones with orientations that may not be strictly compatible with northwest-southeast shortening. Our results are consistent with models invoking a convergent or transpressive tectonic margin at the southern margin of Laurentia at ca. 1.4 Ga. Alternatively, however, we propose that the 1.4-Ga granites may have been emplaced into an ambient, generally compressional, intracontinental stress field in the absence of an active plate margin at the southern margin of Laurentia. An intracontinental stress field coupled with a large-scale thermal anomaly would allow local deviations from overall northwest-southeast shortening while still explaining why the majority of studied 1.4-Ga plutons record shortening strains.

AB - The transcontinental belt of ca. 1.4-Ga granite plutons that extends from southern California to Labrador has conventionally been interpreted as either "anorogenic" or emplaced in an extensional tectonic setting. Recent studies in the western United States, however, demonstrate that several ca. 1.4-Ga plutons were emplaced in a broadly northwest-southeast shortening strain field. Our study of the 1404 + 1.5-Ma Boriana Canyon pluton, northwestern Arizona, establishes the emplacement age by U-Pb zircon analysis and reveals synintrusive deformation consistent with northwest-southeast shortening. The Boriana Canyon pluton contains northeast-striking mylonite zones that record reverse-sense, northwest-side-up motion. Undeformed late dikes crosscut solid-state deformation zones in the pluton, indicating synintrusive deformation. The mylonites also contain a continuum of microstructures that record high-temperature plastic deformation through low-temperature brittle deformation. This study adds to the growing catalog of ca. 1.4-Ga plutons deformed by synintrusive, broadly northwest-southeast shortening strains. Several studies, however, document shear zones with orientations that may not be strictly compatible with northwest-southeast shortening. Our results are consistent with models invoking a convergent or transpressive tectonic margin at the southern margin of Laurentia at ca. 1.4 Ga. Alternatively, however, we propose that the 1.4-Ga granites may have been emplaced into an ambient, generally compressional, intracontinental stress field in the absence of an active plate margin at the southern margin of Laurentia. An intracontinental stress field coupled with a large-scale thermal anomaly would allow local deviations from overall northwest-southeast shortening while still explaining why the majority of studied 1.4-Ga plutons record shortening strains.

UR - http://www.scopus.com/inward/record.url?scp=2342592679&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=2342592679&partnerID=8YFLogxK

U2 - 10.1086/381656

DO - 10.1086/381656

M3 - Article

AN - SCOPUS:2342592679

VL - 112

SP - 165

EP - 183

JO - Journal of Geology

JF - Journal of Geology

SN - 0022-1376

IS - 2

ER -