TY - JOUR
T1 - Structural and kinematic evolution of the teslin suture zone, Yukon
T2 - record of an ancient transpressional margin
AU - Hansen, Vicki L.
N1 - Funding Information:
Acknowledgements--This work was supported by the Exploration and Geological Services Division of DIANA, Whitehorse, Yukon, by
PY - 1989
Y1 - 1989
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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U2 - 10.1016/0191-8141(89)90007-2
DO - 10.1016/0191-8141(89)90007-2
M3 - Article
AN - SCOPUS:0024857182
SN - 0191-8141
VL - 11
SP - 717
EP - 733
JO - Journal of Structural Geology
JF - Journal of Structural Geology
IS - 6
ER -