Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1130/B31797.1 |
Microscopic anatomy of a "hot-on-cold" shear zone: Insights from quartzites of the Main Central Thrust in the Alaknanda region (Garhwal Himalaya) | |
Hunter, Nicholas J. R.1; Weinberg, Roberto F.1; Wilson, Christopher J. L.1; Luzin, Vladimir2; Misra, Santanu3 | |
2018-09-01 | |
发表期刊 | GEOLOGICAL SOCIETY OF AMERICA BULLETIN
![]() |
ISSN | 0016-7606 |
EISSN | 1943-2674 |
出版年 | 2018 |
卷号 | 130页码:1519-1539 |
文章类型 | Article |
语种 | 英语 |
国家 | Australia; India |
英文摘要 | Microstructures inside exhumed crustal shear zones provide a window into the mechanics of Earth's interior. However, difficulties remain in quantifying their physical properties due to the numerous macro-, meso-, and grain-scale factors controlling their development and modification. The complex interplay between these factors has meant that inconsistencies remain between the knowledge derived from controlled laboratory deformation experiments and that from empirical observations in nature. We present a quantitative toolbox for identifying variations in the deformation characteristics of shear zones, using the microstructure and crystallographic preferred orientation (CPO) of quartz. The Main Central Thrust in the Alaknanda Valley (NW Himalaya) is an archetypal major ductile thrust zone that contains abundant quartzites and quartz-mica schists that permit microstructural characterization across gradients in strain and temperature. Using a combination of detailed microstructural analysis and neutron diffraction, we show that quartzites across the Main Central Thrust sequence are characterized by: (1) systematic increases in grain lobateness and coarseness, indicating the transition from subgrain rotation (SGR) to dominant grain boundary migration (GBM) dynamic recrystallization; (2) a concomitant shift in CPO from oblique (top-to-the-SSW) girdles to a strong single y maximum, indicating increasing activity of prismatic slip; and (3) high CPO intensities coinciding with the switch to GBM and prismatic slip activity. Our analyses suggest the Main Central Thrust may be characterized as an similar to 3-km-wide zone of dominantly non-coaxial deformation coinciding with a sharp change in peak metamorphic temperatures, from similar to 450 degrees C in the footwall to 750-800 degrees C in the hanging wall. We suggest that the observed systematic microstructural and CPO transitions may typify the deformational behavior of quartz in the Main Central Thrust across the wider Himalaya. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000443133000007 |
WOS关键词 | CRYSTALLOGRAPHIC PREFERRED ORIENTATION ; PARALLEL SUBGRAIN BOUNDARIES ; NATURALLY DEFORMED QUARTZ ; CENTRAL NEPAL HIMALAYA ; C-AXIS FABRICS ; GRAIN-SIZE ; DEFORMATION MECHANISMS ; PLASTIC-DEFORMATION ; DISLOCATION CREEP ; MICROSTRUCTURAL GEOTHERMOBAROMETER |
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/24810 |
专题 | 地球科学 |
作者单位 | 1.Monash Univ, Sch Earth Atmosphere & Environm, Clayton, Vic 3800, Australia; 2.ANSTO, Australian Ctr Neutron Scattering, Lucas Heights, NSW 2234, Australia; 3.Indian Inst Technol Kanpur, Dept Earth Sci, Kanpur 208016, Uttar Pradesh, India |
推荐引用方式 GB/T 7714 | Hunter, Nicholas J. R.,Weinberg, Roberto F.,Wilson, Christopher J. L.,et al. Microscopic anatomy of a "hot-on-cold" shear zone: Insights from quartzites of the Main Central Thrust in the Alaknanda region (Garhwal Himalaya)[J]. GEOLOGICAL SOCIETY OF AMERICA BULLETIN,2018,130:1519-1539. |
APA | Hunter, Nicholas J. R.,Weinberg, Roberto F.,Wilson, Christopher J. L.,Luzin, Vladimir,&Misra, Santanu.(2018).Microscopic anatomy of a "hot-on-cold" shear zone: Insights from quartzites of the Main Central Thrust in the Alaknanda region (Garhwal Himalaya).GEOLOGICAL SOCIETY OF AMERICA BULLETIN,130,1519-1539. |
MLA | Hunter, Nicholas J. R.,et al."Microscopic anatomy of a "hot-on-cold" shear zone: Insights from quartzites of the Main Central Thrust in the Alaknanda region (Garhwal Himalaya)".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 130(2018):1519-1539. |
条目包含的文件 | 条目无相关文件。 |
除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。
修改评论