DEFORMATION CHARACTERISTICS AND KINEMATICS OF ACTIVE DETACHMENT FOLD SCARP：A CASE STUDY FROM THE MINGYAOLE ANTICLINE, PAMIR-SOUTHERN TIANSHAN FORELAND

doi:10.3969/j.issn.0253-4967.2014.03.011

Abstract

Abstract:

The fold scarp, a type of geomorphic scarp on the land surface formed by folding without fault offsets on the surface, can be used to constrain folding and slip rates and kinematics and to reconstruct a folding history despite a lack of full constraints on the subsurface structure. Recently, the conceptual, geometric, and kinematic models of fold scarps formed by fault-bend folding(fault-bend fold scarp)were developed. But for other types of fold scarp, there are few detailed investigations till now.
Located at southern foreland of Chinese Tianshan, the Mingyaole anticline is interpreted to be a detachment fold. On the Kezilesu river terraces in the south limb, a series of detachment fold scarps occur. The height, width, and slope of fold scarps on the T₂ and T₃b terraces are ～16m/～40m/～25° and ～20m/～50m/～26° respectively. The scarp locations are correlated with an underlying synclinal hinge separating a 50° dip and a 15°dip domain and the strike of the scarp is parallel with the hinge. Detailed geologic and geomorphic mapping and dGPS survey data reveal important characteristics of detachment fold scarp. 1)The fold scarps are formed by synclinal hinge migration. 2)During initial growth, the height, width and slope of the fold scarp increase gradually. When the fold scarp's horizontal width increases to be at least twice that of the hinge, the slope will approach a maximum, and will subsequently remain constant even as the height and width continue to increase gradually. 3)The scarp height and underlying bedding dips on either side of the hinge can be used to calculate incremental shortening absorbed by the fold scarp. Based on the height ～16m of the fold scarp on the T₂ and its exposure age ～8.0ka, the shortening rate absorbed by south limb of the Mingyaole fold is estimated to be ～1.3mm/a. Despite similarities with fault-bend fold scarps, detachment-fold scarps have some pronounced differences, which suggest that the type of fold scarp should be defined prior to calculating folding rates.

Key words: active fold, fluvial terrace, fold scarp, Mingyaole anticline, Pamir, thrust-related fold, Tianshan

摘要：

褶皱陡坎是褶皱变形过程中形成的地貌陡坎，是近期发现的一种不同于断层陡坎的构造作用形成的陡坎状地貌。在缺少地震反射剖面等深部资料时，利用褶皱陡坎可对活动褶皱的变形特征和生长演化历史进行限定，但迄今为止有关研究较少。位于帕米尔-南天山前陆地区的明尧勒背斜为第四纪活动的滑脱褶皱。在背斜南翼的河流阶地上发育了一系列褶皱陡坎：在T₂和T₃b阶地上，褶皱陡坎的高度/宽度/坡度分别为16m/40m/25°和20m/50m/26°，陡坎位置与下伏基岩中向斜枢纽位置对应。通过对这些褶皱陡坎的分析，得出：1）这些褶皱陡坎是滑脱褶皱通过膝折带迁移机制形成的。2）褶皱陡坎形成初期，陡坎高度、宽度和坡度逐渐增大；当陡坎宽度达到枢纽带宽度2倍时，陡坎坡度将达到最大值；之后尽管陡坎高度和宽度逐渐增大，其坡度将保持恒定。3）褶皱陡坎吸收的缩短增量与陡坎高度和下伏地层倾角间存在定量几何关系。根据T₂阶地上褶皱陡坎的高度约16m和暴露年龄约8ka，估算T₂阶地面暴露以来明尧勒背斜南翼的缩短速率为～1.3mm/a。在上述分析基础上，还对比总结了滑脱褶皱陡坎和断弯褶皱陡坎的异同点。

CLC Number:

P315.2

LI Tao, CHEN Jie, XIAO Wei-peng. DEFORMATION CHARACTERISTICS AND KINEMATICS OF ACTIVE DETACHMENT FOLD SCARP：A CASE STUDY FROM THE MINGYAOLE ANTICLINE, PAMIR-SOUTHERN TIANSHAN FORELAND[J]. SEISMOLOGY AND GEOLOGY, 2014, 36(3): 677-691.

李涛, 陈杰, 肖伟鹏. 滑脱褶皱陡坎的变形特征和运动学模型：以帕米尔-南天山前陆地区明尧勒背斜为例[J]. 地震地质, 2014, 36(3): 677-691.

References

陈杰, Scharer K M, Burbank D W, 等. 2005a. 利用河流阶地限定活动褶皱的类型和生长机制: 运动学模型
[J]. 地震地质, 27(4): 513-529.
CHEN Jie, Scharer K M, Burbank D W, et al. 2005a. Kinematic models of fluvial terraces over active folds: Constraints on the growth mechanism and kinematics of the fault-related folds
[J]. Seismology and Geology, 27(4): 513-529(in Chinese).
陈杰, Scharer K M, Burbank D W, 等. 2005b. 西南天山明尧勒背斜的第四纪滑脱褶皱作用
[J]. 地震地质, 27(4): 530-547.
CHEN Jie, Scharer K M, Burbank D W, et al. 2005b. Quaternary detachment folding of the Mingyaole anticline, southwestern Tianshan
[J]. Seismology and Geology, 27(4): 530-547(in Chinese).
冯先岳. 1994. 新疆乌恰地震地表破裂带
[A]. 见: 国家地震局地质研究所编: 活动断裂研究(3). 北京: 地震出版社. 45-55.
FENG Xian-yue. 1994. Surface rupture associated with the 1985 Wuqia earthquake in Xinjiang
[A]. In: Institute of Geology, SSB(ed). Research of Active Fault (3). Seismological Press, Beijing. 45-55(in Chinese).
何登发, Suppe J, 贾承造. 2005. 断层相关褶皱理论与应用研究新进展
[J]. 地学前缘, 12(4): 353-364.
HE Deng-fa, Suppe J, JIA Cheng-zao. 2005. New advances in theory and application of fault-related folding
[J]. Earth Science Frontiers, 12(4): 353-364(in Chinese).
李涛, 陈杰, 肖伟鹏, 等. 2011. 西南天山前缘乌拉根背斜南翼逆断层的发现及其地质意义
[J]. 地震地质, 33(2): 277-288. doi: 10.3969/j.issn.0253-4967.2011.02.003.
LI Tao, CHEN Jie, XIAO Wei-peng, et al. 2011. The discovery and geologic significance of the thrust at south limb of the Wulagen anticline, south margin of the southwestern Tianshan
[J]. Seismology and Geology, 33(2): 277-288(in Chinese).
李涛, 陈杰, 肖伟鹏, 等. 2013. 帕米尔-天山对冲带明尧勒背斜西南倾伏端晚第四纪褶皱变形
[J]. 地震地质, 35(2): 234-246. doi: 10.3969/j.issn.0253-4967.2013.02.004.
LI Tao, CHEN Jie, XIAO Wei-peng, et al. 2013. Late-Quaternary folding deformation of the Mingyaole anticline southwestern tip, Pamir-Tianshan convergent zone
[J]. Seismology and Geology, 35(2): 234-246(in Chinese).
李涛, 陈杰. 2014. 利用河流阶地限定活动逆断层相关褶皱晚第四纪变形机制和速率: 方法与认识
[J]. 地震地质, 待刊.
LI Tao, CHEN Jie. 2014. Using deformation fluvial terraces to constrain growth mechanism and rates of thrust related fold: Methods and recognition
[J]. Seismology and Geology(in press).
卢华复, 王胜利, 贾东, 等. 2002. 天山中段南麓的第四纪褶皱作用
[J]. 科学通报, 47(21): 1675-1679.
LU Hua-fu, WANG Sheng-li, JIA Dong, et al. 2002. Quaternary folding in the south piedmont of central segment of Tianshan Mountains
[J]. Chinese Science Bulletin, 47(21): 1675-1679(in Chinese).
杨晓东. 2013. 西南天山-帕米尔前陆盆地活动弯滑断层陡坎与地震
[D]:
[学位论文]. 北京: 中国地震局地质研究所.
YANG Xiao-dong. 2013. Active flexural-slip fault scarps and earthquakes in the southwest Tianshan-Pamir foreland basin
[D]. Ph D thesis. Institute of Geology, China Earthquake Administration, Beijing.
Chen Y G, Lai K Y, Lee Y H, et al. 2007. Coseismic fold scarps and their kinematic behavior in the 1999 Chi-Chi earthquake, Taiwan
[J]. Journal of Geophysical Research, 112: B03S02. doi: 10.1029/2006JB004388.
Epard J L, Groshong R H. 1993. Excess area and depth to detachment
[J]. Aapg Bull, 77(8): 1291-1302.
Hubert-Ferrari A, Suppe J, Gonzalez-Mieres R, et al. 2007. Mechanisms of active folding of the landscape(southern Tianshan, China)
[J]. Journal of Geophysical Research, 112:B03S09. doi: 10.1029/2006JB004362.
Li T, Chen J, Thompson J A, et al. 2012. Equivalency of geologic and geodetic rates in contractional orogens: New insights from the Pamir Frontal Thrust
[J]. Geophysical Research Letters, 39. doi: 10.1029/2012GL051782.
Li T, Chen J, Thompson J A, et al. 2013. Quantification of three-dimensional folding using fluvial terraces: A case study from the Mushi anticline, northern margin of the Chinese Pamir
[J]. Journal of Geophysical Research, 112, B03S09. doi: 10.1029/2006JB004362.
Poblet J, McClay K. 1996. Geometry and kinematics of single layer detachment folds
[J]. AAPG Bull, 80: 1085-1109.
Poblet J, McClay K, Storti F, et al. 1997. Geometries of syntectonic sediments associated with single-layer detachment folds
[J]. Journal of Structural Geology, 19: 369-381.
Poblet J. 2012. 2D kinematic models of growth fault-related folds in contractional settings
[A]. In: Cathy Busby and Antonio Azor(eds). Tectonics of Sedimentary Basin: Recent Advances, First Edition. Blackwell Publishing Ltd.
Scharer K M, Burbank D W, Chen J, et al. 2004. Detachment folding in the southwestern Tianshan-Tarim foreland, China: Shortening estimates and rates
[J]. Journal of Structural Geology, 26: 2119-2137.
Scharer K M, Burbank D W, Chen J, et al. 2006. Kinematic models of fluvial terraces over active detachment fold: Constraints on the growth mechanism of the Kashi-Atushi fold system, Chinese Tianshan
[J]. Geological Society of American Bulletin, 118: 1006-1021. doi: 10.1130/B25835.1.
Suppe J. 1983. Geometry and kinematics of fault-bend folding
[J]. American Journal of Science, 283: 684-721.
Suppe J, Medwedef D A. 1990. Geometry and kinematics of fault-propagation folding
[J]. Ecologae Geol Helv, 83(3): 409-454.
Suppe J, Chou G T, Hook S C. 1992. Rates of folding and faulting determined from growth strata
[A]. In: McClay K(ed). Thrust tectonics. London: Chapman & Hall.
Suppe J, Sabat F, Munoz J A, et al. 1997. Bed-by-bed fold growth by kink-band migration: Sant Llorenc de Morunys, eastern Pyrenees
[J]. Journal of Structural Geology, 19(3-4): 443-461.
Thompson S C, Weldon R J, Rubin C M, et al. 2002. Late Quaternary slip rates across the central Tien Shan, Kyrgyzstan, central Asia
[J]. Journal of Geophysical Research, 107(B9): 2203. doi: 10.1029/2001JB000596.
Thompson S C. 2013. Neogene tectonic evolution of the NE Pamir margin, NW China
[D]. Ph D thesis. University of California, Santa Barbara.6-56.

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