气候变化领域集成服务门户(CCPortal): Polyphase or time-dependent kinematics and quaternary reactivation of thrust bounding Baijnath Klippe: western Kumaun Himalaya; India

CCPortal

DOI	10.1007/s00531-018-1662-2
	Polyphase or time-dependent kinematics and quaternary reactivation of thrust bounding Baijnath Klippe: western Kumaun Himalaya; India
	Joshi N.; Singh S.; Pant P.D.; Puniya M.K.; Kothyari G.C.
发表日期	2019
ISSN	14373254
起始页码	455
结束页码	473
卷号	108 期号:2
英文摘要	The morphotectonic elements of the Baijnath Klippe (BK) have been examined to understand the kinematics of the Inner Kumaun Lesser Himalaya from Tertiary to Late Quaternary. The BK is bounded by two thrusts: the Askot Thrust (AT), to the north and the Baijnath Thrust (BjT), to the south. The older (20 Ma) hanging wall rocks (mylonites and phyllites) are underlain and surrounded by quartzites (equivalent to Nagthat Formation of Outer Lesser Himalaya). The kinematics study and strain analysis along Dewal–Narayanbagarh transect provides the varied intensity of deformation (D 1 , D 2, and D 3 ) within the zone of BK. The D 1 event is characterized by isoclinal tight folds in phyllite and mylonite; the D 2 phase is characterized by open folding in mylonite. However, the youngest event D 3 phase is observed as a regional synclinal folding of BK and associated rocks. The presence of 1–3-km-thick mylonite zone parallel to the thrust planes is related to the compressional event of Miocene age. The geomorphic pattern and chronologically constraints (OSL ages) with spatial variability in the incision/uplift rate suggests that the terrain is undergoing differential crustal deformation during Late Quaternary. Kinematic indicators such as streaky foliations, S–C foliation, mantled porphyroclasts, micro-shears with bookshelf gliding, and mica fish found in mylonites (macroscopic as well as microscopic) indicate ductile deformation in the area. We used Flinn plot (R f /ϕ) and Fry (Tectonophysics 60:89–105, 1979) analysis to delineate the finite strain pattern in 21 oriented samples collected across the BK bound thrusts (BjT and AT). The strain analysis revealed an increasing trend of strained quartz grains, which presents triaxialoblate strain geometry (flattening i.e., 0 < k < 1) towards the structural discontinuity. The textural (chessboard, myrmekite, undulose extinction and fracturing in quartz and feldspar) and mineralogical properties (non-flaky) of quartz and feldspar indicate the temperature of deformation and mylonitization ranging 300–500 °C. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Baijnath Klippe; Lesser Himalaya; Polyphase deformation; Quaternary
语种	英语
scopus关键词	ductile deformation; feldspar; folding; mylonite; mylonitization; quartz; Quaternary; strain; thrust; Himalayas; India; Kumaun Himalayas; Lesser Himalayas; Uttarakhand
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147877
作者单位	Institute of Seismological Research, Gandhinagar, Gujarat, India; Department of Geology, Kumaun University Nainital, Uttarakhand, India; Faculty of Science, Uttarakhand Open University, Uttarakhand, India; National Geotechnical Facility, Survey of India, 11C Circular Road, Dalanwala, Dehradun, India
推荐引用方式 GB/T 7714	Joshi N.,Singh S.,Pant P.D.,et al. Polyphase or time-dependent kinematics and quaternary reactivation of thrust bounding Baijnath Klippe: western Kumaun Himalaya; India[J],2019,108(2).
APA	Joshi N.,Singh S.,Pant P.D.,Puniya M.K.,&Kothyari G.C..(2019).Polyphase or time-dependent kinematics and quaternary reactivation of thrust bounding Baijnath Klippe: western Kumaun Himalaya; India.International Journal of Earth Sciences,108(2).
MLA	Joshi N.,et al."Polyphase or time-dependent kinematics and quaternary reactivation of thrust bounding Baijnath Klippe: western Kumaun Himalaya; India".International Journal of Earth Sciences 108.2(2019).