Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1130/B31922.1 |
Evidence for deep crustal seismic rupture in a granulite-facies, intraplate, strike-slip shear zone, northern Saskatchewan, Canada | |
Orlandini, Omero F.1; Mahan, Kevin H.1; Williams, Michael J.2; Regan, Sean P.2; Mueller, Karl J.1 | |
2019-03-01 | |
发表期刊 | GEOLOGICAL SOCIETY OF AMERICA BULLETIN
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ISSN | 0016-7606 |
EISSN | 1943-2674 |
出版年 | 2019 |
卷号 | 131页码:403-425 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Pseudotachylyte veins are solidified frictional melt generated by localized highstrain-rate deformation, and they are commonly considered to be reliable geological indicators of seismic slip. While originally thought to occur primarily in the upper crust, field studies suggest pseudotachylyte can also form far below the frictional-viscous transition. This implies a more complex interplay between brittle and crystal-plastic deformation in crustal-scale fault systems. We report a new example of deep pseudotachylyte from the Paleoproterozoic granulite-facies strikeslip Cora Lake shear zone in northern Saskatchewan, Canada. Multiple generations of pseudotachylyte have been variably overprinted by plastic deformation and growth of high-grade metamorphic mineral assemblages (including garnet, orthopyroxene, and/or clinopyroxene). Undeformed pseudotachylyte generation surfaces locally display sinistral offsets, and deformed pseudotachylyte shows unambiguous shear sense indicators compatible with left-lateral Cora Lake shear zone kinematics. The vein networks are commonly proximal to and inherit kinematically compatible semibrittle shear fractures. Thermobarometry and modeling of mineral stability fields for the overprinted pseudotachylyte suggest vein generation between 0.7 and 0.8 GPa and 700 degrees C and 800 degrees C (corresponding to depths from 24 to 28 km). Combined with the kinematic compatibility and the well-constrained regional exhumation history, this suggests that the Cora Lake pseudotachylyte formed contemporaneously with the waning stages of deformation in the shear zone and constitutes one of the deepest examples of fault-related pseudotachylyte yet reported in North America. Evidence exists for several possible formation mechanisms, including in situ generation via ductile shear heating-induced plastic instabilities, as well as from interaction with earthquakes nucleating in the overlying brittle fault system. All of these possible mechanisms ultimately suggest a more rheologically complex environment than might typically be expected for these lower-crustal pressure and temperature conditions. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000460031700004 |
WOS关键词 | SNOWBIRD TECTONIC ZONE ; HIGH-TEMPERATURE METAMORPHISM ; ATHABASCA MYLONITE ZONE ; INTERMEDIATE-DEPTH EARTHQUAKES ; FRICTIONAL MELTING PROCESSES ; WESTERN CHURCHILL PROVINCE ; HIGH-PRESSURE METAMORPHISM ; LOWER CONTINENTAL-CRUST ; SAN-ANDREAS FAULT ; HIGH-P GRANULITES |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/24576 |
专题 | 地球科学 |
作者单位 | 1.Univ Colorado, Dept Geol Sci, UCB 399, Boulder, CO 80309 USA; 2.Univ Massachusetts, Dept Geosci, 627 North Pleasant St,233 Morrill Sci Ctr, Amherst, MA 01003 USA |
推荐引用方式 GB/T 7714 | Orlandini, Omero F.,Mahan, Kevin H.,Williams, Michael J.,et al. Evidence for deep crustal seismic rupture in a granulite-facies, intraplate, strike-slip shear zone, northern Saskatchewan, Canada[J]. GEOLOGICAL SOCIETY OF AMERICA BULLETIN,2019,131:403-425. |
APA | Orlandini, Omero F.,Mahan, Kevin H.,Williams, Michael J.,Regan, Sean P.,&Mueller, Karl J..(2019).Evidence for deep crustal seismic rupture in a granulite-facies, intraplate, strike-slip shear zone, northern Saskatchewan, Canada.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,131,403-425. |
MLA | Orlandini, Omero F.,et al."Evidence for deep crustal seismic rupture in a granulite-facies, intraplate, strike-slip shear zone, northern Saskatchewan, Canada".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 131(2019):403-425. |
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