P-T-t estimation of deformation in low-grade quartz-feldspar-bearing rocks using thermodynamic modelling and 40Ar/39Ar dating techniques: example of the Plan-de-Phasy shear zone unit (Brianconnais Zone, Western Alps)

被引：47

作者：

Lanari, Pierre ^{[1
]}

Rolland, Yann ^{[2
]}

Schwartz, Stephane ^{[3
]}

Vidal, Olivier ^{[3
]}

Guillot, Stephane ^{[3
]}

Tricart, Pierre ^{[3
]}

Dumont, Thierry ^{[3
]}

机构：

[1] Univ Bern, Inst Geol Sci, CH-3012 Bern, Switzerland

[2] UNS, CNRS, UMR7329, Geoazur, F-06560 Valbonne, France

[3] Univ Grenoble 1, CNRS, ISTerre, F-38041 Grenoble, France

来源：

TERRA NOVA | 2014年 / 26卷 / 02期

关键词：

QUEYRAS SCHISTES LUSTRES; METAMORPHIC EVOLUTION; WHITE MICA; SUBDUCTION WEDGE; FAULT-ZONE; K-AR; MASSIF; CONSTRAINTS; EXHUMATION; SECTION;

D O I：

10.1111/ter.12079

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

Pressure-Temperature-time (P-T-t) estimates of the syn-kinematic strain at the peak-pressure conditions reached during shallow underthrusting of the Brianconnais Zone in the Alpine subduction zone was made by thermodynamic modelling and 40Ar/39Ar dating in the Plan-de-Phasy unit (SE of the Pelvoux Massif, Western Alps). The dated phengite minerals crystallized syn-kinematically in a shear zone indicating top-to-the-N motion. By combining X-ray mapping with multi-equilibrium calculations, we estimate the phengite crystallization conditions at 270 +/- 50 degrees C and 8.1 +/- 2kbar at an age of 45.9 +/- 1.1Ma. Combining this P-T-t estimate with data from the literature allows us to constrain the timing and geometry of Alpine continental subduction. We propose that the Brianconnais units were scalped on top of the slab during ongoing continental subduction and exhumed continuously until collision.

引用

页码：130 / 138

页数：9