Orogen-transverse tectonic window in the Eastern Himalayan fold belt: A superposed buckling model

被引:32
作者
Bose, Santanu [1 ]
Mandal, Nibir [2 ]
Acharyya, S. K. [2 ]
Ghosh, Subhajit [1 ]
Saha, Puspendu [1 ]
机构
[1] Univ Calcutta, Dept Geol, Kolkata 700019, W Bengal, India
[2] Univ Jadavpur, Dept Geol Sci, Kolkata 700032, India
关键词
Rangit window; Ductile deformations; Multi-ordered superposed buckling; Types 1 and 2 interference patterns; Tista dome; DARJEELING-SIKKIM HIMALAYA; LESSER HIMALAYA; THRUST BELT; INDIA; EVOLUTION; COLLISION; PATTERNS; NEPAL; INTERFERENCE; STRATIGRAPHY;
D O I
10.1016/j.jsg.2014.05.008
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
The Eastern Lesser Himalayan fold-thrust belt is punctuated by a row of orogen-transverse domal tectonic windows. To evaluate their origin, a variety of thrust-stack models have been proposed, assuming that the crustal shortening occurred dominantly by brittle deformations. However, the Rangit Window (RW) in the Darjeeling-Sikkim Himalaya (DSH) shows unequivocal structural imprints of ductile deformations of multiple episodes. Based on new structural maps, coupled with outcrop-scale field observations, we recognize at least four major episodes of folding in the litho-tectonic units of DSH. The last episode has produced regionally orogen-transverse upright folds (F-4), the interference of which with the third-generation (F-3) orogen-parallel folds has shaped the large-scale structural patterns in DSH. We propose a new genetic model for the RW, invoking the mechanics of superposed buckling in the mechanically stratified litho-tectonic systems. We substantiate this superposed buckling model with results obtained from analogue experiments. The model explains contrasting F3 F4 interferences in the Lesser Himalayan Sequence (LHS). The lower-order (terrain-scale) folds have undergone superposed buckling in Mode 1, producing large-scale domes and basins, whereas the RW occurs as a relatively higher-order dome nested in the first-order Tista Dome. The Gondwana and the Proterozoic rocks within the RW underwent superposed buckling in Modes 3 and 4, leading to Type 2 fold interferences, as evident from their structural patterns. (C) 2014 Elsevier Ltd. All rights reserved.
引用
收藏
页码:24 / 41
页数:18
相关论文
共 53 条
[1]  
Acharyya S.K., 1998, J Nepal Geol, Soc., V18, DOI 10.3126/jngs.v18i0.32192
[2]  
Acharyya S.K., 1989, Geological Survey of India Special Publication 22, P5
[3]   Crustal structure of the Darjeeling-Sikkim Himalaya and southern Tibet [J].
Acton, C. E. ;
Priestley, K. ;
Mitra, S. ;
Gaur, V. K. .
GEOPHYSICAL JOURNAL INTERNATIONAL, 2011, 184 (02) :829-852
[4]  
[Anonymous], 1977, 4 INT GOND S IND
[5]  
[Anonymous], 2011, INDIAN J GEOSCIENCES
[6]  
[Anonymous], 2003, GSA TODAY
[7]   Mountain building, erosion, and the seismic cycle in the Nepal Himalaya [J].
Avouac, JP .
ADVANCES IN GEOPHYSICS, VOL 46, 2003, 46 :1-80
[8]   Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation [J].
Beaumont, C ;
Jamieson, RA ;
Nguyen, MH ;
Lee, B .
NATURE, 2001, 414 (6865) :738-742
[9]   STRATIGRAPHIC EVIDENCE FOR AN EARLY COLLISION BETWEEN NORTHWEST INDIA AND ASIA [J].
BECK, RA ;
BURBANK, DW ;
SERCOMBE, WJ ;
RILEY, GW ;
BARNDT, JK ;
BERRY, JR ;
AFZAL, J ;
KHAN, AM ;
JURGEN, H ;
METJE, J ;
CHEEMA, A ;
SHAFIQUE, NA ;
LAWRENCE, RD ;
KHAN, MA .
NATURE, 1995, 373 (6509) :55-58
[10]  
Bhargava O.N., 1995, Spec. Publ. Ser. Geol. Surv, V39, P245