Structural and kinematic evolution of the teslin suture zone, Yukon

record of an ancient transpressional margin

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32 Citations (Scopus)

Abstract

The Teslin suture zone (TSZ), Yukon, which forms the fundamental boundary between rocks deposited along the ancient margin of North America, and allochthonous terranes to the west, preserves a complex history of pre-mid-Jurassic convergence and dextral strike-slip translation which is overprinted locally by late Cretaceous dextral strike-slip shear. The TSZ, comprised of a 15-20 km thick structural sequence of ductilely deformed sedimentary and volcanic strata, basalt, peridotite and granitoids, is divisible into distinct elongate structural domains based on the distribution of two well-defined but differently oriented stretching lineations, Lds and Lss, Lds and Lss both formed during non-coaxial ductile deformation; Lds trends E-W and plunges down-dip, whereas Lss trends NNW-SSE and plunges shallowly. Two 1-2 km wide, NNW-trending anastomosing shear zones of Lss cross-cut Lds structures, indicating Lss is younger. Other field relations indicate further that Lds began forming earlier than Lss, followed by a period of coeval Lds and Lss formation; latest motion was dominantly parallel to Lss. Synkinematic mineral assemblages associated with both Lds- and Lss-related structures record greenschist to albite-epidote amphibolite facies conditions. Lds tectonites record a complex movement history: to the west textural asymmetries indicate west-side-down, or normal shear, whereas in eastern domains top-to-the-east thrust-style asymmetries dominate. Lss tectonites consistently record dextral, or top-to-the-north, shear parallel to Lss. Tectonic motion began as chiefly penetrative dip-slip shear (Lds) at a high angle to the present trend of the TSZ, and evolved to dominantly dextral strike-slip shear (Lss) parallel to the trend of the zone. The geometry, kinematics and sequence of deformation in TSZ tectonites evoke a general model of terrane accretion during oblique plate convergence involving initial shortening at a high angle to the convergent margin and progression to margin-parallel translation.

Original languageEnglish (US)
Pages (from-to)717-733
Number of pages17
JournalJournal of Structural Geology
Volume11
Issue number6
DOIs
StatePublished - Jan 1 1989

Fingerprint

suture zone
kinematics
terrane
asymmetry
plate convergence
convergent margin
dip-slip fault
ductile deformation
greenschist
epidote
lineation
history
albite
amphibolite facies
peridotite
shear zone
dip
thrust
Jurassic
basalt

Cite this

@article{726d24f50179495b9c1ece50e0bd3dcd,
title = "Structural and kinematic evolution of the teslin suture zone, Yukon: record of an ancient transpressional margin",
abstract = "The Teslin suture zone (TSZ), Yukon, which forms the fundamental boundary between rocks deposited along the ancient margin of North America, and allochthonous terranes to the west, preserves a complex history of pre-mid-Jurassic convergence and dextral strike-slip translation which is overprinted locally by late Cretaceous dextral strike-slip shear. The TSZ, comprised of a 15-20 km thick structural sequence of ductilely deformed sedimentary and volcanic strata, basalt, peridotite and granitoids, is divisible into distinct elongate structural domains based on the distribution of two well-defined but differently oriented stretching lineations, Lds and Lss, Lds and Lss both formed during non-coaxial ductile deformation; Lds trends E-W and plunges down-dip, whereas Lss trends NNW-SSE and plunges shallowly. Two 1-2 km wide, NNW-trending anastomosing shear zones of Lss cross-cut Lds structures, indicating Lss is younger. Other field relations indicate further that Lds began forming earlier than Lss, followed by a period of coeval Lds and Lss formation; latest motion was dominantly parallel to Lss. Synkinematic mineral assemblages associated with both Lds- and Lss-related structures record greenschist to albite-epidote amphibolite facies conditions. Lds tectonites record a complex movement history: to the west textural asymmetries indicate west-side-down, or normal shear, whereas in eastern domains top-to-the-east thrust-style asymmetries dominate. Lss tectonites consistently record dextral, or top-to-the-north, shear parallel to Lss. Tectonic motion began as chiefly penetrative dip-slip shear (Lds) at a high angle to the present trend of the TSZ, and evolved to dominantly dextral strike-slip shear (Lss) parallel to the trend of the zone. The geometry, kinematics and sequence of deformation in TSZ tectonites evoke a general model of terrane accretion during oblique plate convergence involving initial shortening at a high angle to the convergent margin and progression to margin-parallel translation.",
author = "Hansen, {Vicki L.}",
year = "1989",
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doi = "10.1016/0191-8141(89)90007-2",
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journal = "Journal of Structural Geology",
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TY - JOUR

T1 - Structural and kinematic evolution of the teslin suture zone, Yukon

T2 - record of an ancient transpressional margin

AU - Hansen, Vicki L.

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N2 - The Teslin suture zone (TSZ), Yukon, which forms the fundamental boundary between rocks deposited along the ancient margin of North America, and allochthonous terranes to the west, preserves a complex history of pre-mid-Jurassic convergence and dextral strike-slip translation which is overprinted locally by late Cretaceous dextral strike-slip shear. The TSZ, comprised of a 15-20 km thick structural sequence of ductilely deformed sedimentary and volcanic strata, basalt, peridotite and granitoids, is divisible into distinct elongate structural domains based on the distribution of two well-defined but differently oriented stretching lineations, Lds and Lss, Lds and Lss both formed during non-coaxial ductile deformation; Lds trends E-W and plunges down-dip, whereas Lss trends NNW-SSE and plunges shallowly. Two 1-2 km wide, NNW-trending anastomosing shear zones of Lss cross-cut Lds structures, indicating Lss is younger. Other field relations indicate further that Lds began forming earlier than Lss, followed by a period of coeval Lds and Lss formation; latest motion was dominantly parallel to Lss. Synkinematic mineral assemblages associated with both Lds- and Lss-related structures record greenschist to albite-epidote amphibolite facies conditions. Lds tectonites record a complex movement history: to the west textural asymmetries indicate west-side-down, or normal shear, whereas in eastern domains top-to-the-east thrust-style asymmetries dominate. Lss tectonites consistently record dextral, or top-to-the-north, shear parallel to Lss. Tectonic motion began as chiefly penetrative dip-slip shear (Lds) at a high angle to the present trend of the TSZ, and evolved to dominantly dextral strike-slip shear (Lss) parallel to the trend of the zone. The geometry, kinematics and sequence of deformation in TSZ tectonites evoke a general model of terrane accretion during oblique plate convergence involving initial shortening at a high angle to the convergent margin and progression to margin-parallel translation.

AB - The Teslin suture zone (TSZ), Yukon, which forms the fundamental boundary between rocks deposited along the ancient margin of North America, and allochthonous terranes to the west, preserves a complex history of pre-mid-Jurassic convergence and dextral strike-slip translation which is overprinted locally by late Cretaceous dextral strike-slip shear. The TSZ, comprised of a 15-20 km thick structural sequence of ductilely deformed sedimentary and volcanic strata, basalt, peridotite and granitoids, is divisible into distinct elongate structural domains based on the distribution of two well-defined but differently oriented stretching lineations, Lds and Lss, Lds and Lss both formed during non-coaxial ductile deformation; Lds trends E-W and plunges down-dip, whereas Lss trends NNW-SSE and plunges shallowly. Two 1-2 km wide, NNW-trending anastomosing shear zones of Lss cross-cut Lds structures, indicating Lss is younger. Other field relations indicate further that Lds began forming earlier than Lss, followed by a period of coeval Lds and Lss formation; latest motion was dominantly parallel to Lss. Synkinematic mineral assemblages associated with both Lds- and Lss-related structures record greenschist to albite-epidote amphibolite facies conditions. Lds tectonites record a complex movement history: to the west textural asymmetries indicate west-side-down, or normal shear, whereas in eastern domains top-to-the-east thrust-style asymmetries dominate. Lss tectonites consistently record dextral, or top-to-the-north, shear parallel to Lss. Tectonic motion began as chiefly penetrative dip-slip shear (Lds) at a high angle to the present trend of the TSZ, and evolved to dominantly dextral strike-slip shear (Lss) parallel to the trend of the zone. The geometry, kinematics and sequence of deformation in TSZ tectonites evoke a general model of terrane accretion during oblique plate convergence involving initial shortening at a high angle to the convergent margin and progression to margin-parallel translation.

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