天山东端喀尔里克山北缘断裂晚第四纪活动与转换挤压变形

doi:10.3969/j.issn.0253-4967.2022.01.004

摘要/Abstract

摘要：

喀尔里克山位于天山最东端, 是天山造山带往东地貌和构造的终止端, 研究该地区断裂结构和运动学特征对于全面认识天山新生代变形模式具有重要意义。喀尔里克山北缘断裂呈弧形展布在喀尔里克山北侧, 向E延伸与戈壁-天山左旋走滑断裂系相连。根据其走向和运动性质的差异可将喀尔里克山北缘断裂分为东、西2段, 西段长约61km, 走向NW, 呈逆冲性质, 断裂活动在山前洪积扇上形成了多条断层陡坎。利用光释光测年方法对变形阶地进行定年, 得到西段全新世垂直滑动速率介于0.19~0.35mm/a之间, 该滑动速率略大于喀尔里克山南侧的哈密盆地北缘断裂的垂直滑动速率, 这与山体向S掀斜的地貌特征一致。东段长约95km, 走向NE, 以左旋走滑变形为主, 断裂左旋错断了一系列冲沟和河流阶地, 剖面显示该断裂段还具有一定逆冲分量。喀尔里克山北缘断裂与山体两侧其他逆冲断裂共同构成了戈壁-天山左旋走滑断裂系的挤压性马尾状端部构造, 这些断裂在深部收敛会聚并在剖面上呈现不对称的正花状构造。喀尔里克山体的抬升受南北两侧逆冲断裂和东侧左旋走滑断裂共同控制, 表现为转换挤压变形抬升的特征, 山体通过山前逆冲断裂向盆地内部的迁移逐渐向外扩展。

关键词: 喀尔里克山北缘断裂, 运动特征, 转换挤压变形, 天山东端

Abstract:

Karlik Tagh and other lesser ranges of the easternmost Tian Shan are natural laboratory for studying the fault architecture of an active termination zone of an intraplate mountain belt. The Karlik Tagh is located at the easternmost Tian Shan which is active due to the collision of India plate and Eurasian plate in Cenozoic and this range represents the geomorphological and structural end of Tian Shan. Therefore, studying the geometry and kinematics of active faults distributed at this area has important implications for understanding the dynamics features of the end porting of the Cenozoic orogenic belt. This paper is focused on the North Karlik Tagh Fault(KTNF), which is an important active structure at the easternmost Tian Shan. This fault extends about 180km and is gently distributed between the Yiwu Basin and the north of Karlik Tagh. Based on remote sensing and detailed field research, we propose to subdivide the NKTF into 2 segments based on its variation in strike and motion characteristics.
At the west of the NKTF, the west segment is mainly distributed at south of Yanchi County and extends intermittently about 61km. The fault trace along Yanchi segment is obvious and expressed by several linear fault scarps on the foreland alluvial fan surfaces north of Karlik Tagh. Outcrop on a channel wall shows that the fault dips SW and thrusts directly to the NE. Topographic profiles across the scarps have shown that the minimum vertical offset is(1.3±0.5)m, which can be caused by a single earthquake rupture. The maximum vertical offset is(7.3±0.3)m. An OSL dating sample was obtained at 70cm below the T1 terrace surface. And we get the deposition age of(7.0±1.4)ka. Based on the OSL dating of deformed T1 terrace and the vertical displacement of(1.3±0.5)m of T1 and vertical displacement of(2.5±0.2)m of T2, a vertical slip rate of 0.19~0.35mm/a can be calculated. This vertical rate is slightly larger than that of the North Hami Basin Fault, which is consistent with the S-directed tilt of the Karlik Tagh.
At south of Xiamaya town, the east segment of NKTF changes its strike and bends to NE, extending nearly 95km. Toward the east, this fault is connected with the west end of Gobi-Tianshan fault system(GTSFS)at the border of China and Mongolia. There are clear evidences of recent activity of this fault, including well-preserved scarps and offset streams on the alluvial sediments. And this fault segment is very obvious because of linear features on the Google Earth image. About 23km southeast of Xiamaya town, the fault trace runs across a north-flowing river, causing remarkable sinistral offset of the T3/T2 terrace ridge with the maximum displacement of(172±20)m. At about 10km northeast of this river, the NKTF passes through a massif with steep slope on the south and gentle slope on the north. Field observation of a hand-dug outcrop has shown that this fault dips N156°E. In addition, the fault also displays reverse faulting component and dislocates the gravel-bearing silt sedment by about 2.0m.
At north of Karlik Tagh, several NW-trending faults can be interpreted on the satellite image. These faults extend short and form a clear boundary between bedrock and Quaternary sediments. Although there are no obvious deformations in the sediment such as diluvial fans or river terraces in the valley, the good linear characteristics on both sides of the valley indicate that these faults have been active since Quaternary. Because these faults are nearly parallel to the western segment of the northern margin of the Karlik Mountains, and there is no geomorphological evidence of horizontal movement of the faults, it can be inferred that the faults on both sides of the Adak Valley are mainly dominated by vertical movement.
The Karlik Tagh North Fault, together with, the north margin faults of Hami Basin and other NW-trending secondary faults in the north side of Karlik Mountain constitute the horse-tail end structure of Gobi-Tianshan sinistral strike-slip fault system, which regulates and absorbs the sinistral deformation of Gobi-Tianshan fault system and these faults present a positive flower structure in the cross-section. The uplift of Karlik Tagh is controlled by NW thrust fault and NEE left-lateral strike-slip fault, and this range is a typical transpressional mountain in the easternmost Tian Shan.

Key words: North Karlik Tagh Fault, movement feature, transpressional deformation, easternmost Tian Shan

中图分类号:

P315.2

任光雪, 李传友, 孙凯. 天山东端喀尔里克山北缘断裂晚第四纪活动与转换挤压变形[J]. 地震地质, 2022, 44(1): 46-62.

REN Guang-xue, LI Chuan-you, SUN Kai. LATE QUATERNARY ACTIVITY AND TRANSPRESSIONAL DEFORMATION OF THE KARLIK TAGH NORTH FAULT, EASTERNMOST TIANSHAN[J]. SEISMOLOGY AND GEOLOGY, 2022, 44(1): 46-62.

图/表 12

图 1 天山东端喀尔里克山周缘构造及地貌图 a 中亚地区构造简图(修改自Molnar et al., 1984); b 东天山东端及其邻近地区活动构造图; c 横跨喀尔里克山地形与地质剖面图

Fig. 1 Structural and geomorphological map around the Karlik Tagh at the easternmost Tian Shan.

图 2 喀尔里克山北缘断裂西段山前地貌面分期图

Fig. 2 Divisions of frontal morphologic units on east segment of the KTNF.

图 3 喀尔里克山北缘断裂西段沿线的晚第四纪变形地貌面野外照片 a 阔腊段陡坎Google Earth影像图; b 阔腊段陡坎野外照片; c 乌尊巴拉克段陡坎; d 阔腊东侧的高台地

Fig. 3 Field photos of deformed Late Quateranry deposits along the west segment of KTNF.

图 4 a 喀尔里克山北缘断裂西段拜勒乌台克点地形图; b 变形洪积扇面与阶地及采样位置野外照片

Fig. 4 The topography at Bileuteck site on west segment of KTNF(a); Photos of deformed terraces and sampling site(b).

图 5 拜勒乌台克段横跨断层陡坎的地形剖面图(剖面的具体位置见图4a)

Fig. 5 Topographical profiles normal to the fault scarp at Bileuteck site(see Fig.4a for detailed site location).

表1 拜勒乌台克段河流T1阶地的OSL结果

Table 1 The result of OSL dating from the T1 terrace on Bileuteck segment

编号	埋深 /m	²³⁸U/Bg·kg^-1	²²⁶Ra/Bg·kg^-1	²³²Th/Bg·kg^-1	⁴⁰K/Bg·kg^-1	含水量 /%	环境剂量率 /Gy·ka^-1	等效剂量 /Gy	年龄 /ka
KAR-OSL-02	0.7	55.8±9.9	32.2±0.9	45.2±1.0	582.9±19.9	4	3.5±0.2	24.4±4.6	7.0±1.4

图 6 喀尔里克山断裂东段错断阶地的地貌特征 a 喀尔里克山北缘断裂东段位错阶地的Google Earth影像图; b 位错阶地及断层解译图; c 横跨河流剖面图及各级阶地相对河床的高度; d 断裂迹线的野外照片

Fig. 6 Geomorphology of the faulted river terraces at the east segment of KTNF.

图 7 喀尔里克山北缘断裂东段变形地貌的野外照片

Fig. 7 Field photos of deformed landforms on east segment of KTNF.

图 8 下马崖南小隆起的Google Earth影像图红色箭头指示断层迹线, 左上角插图表示隆起下部推测的断裂几何结构示意图

Fig. 8 Google Earth image of the uplifted massif at south of Xiamaya site.

图 9 喀尔里克山北缘断裂东段断层的剖面(a)及剖面解译图(b)

Fig. 9 Outcrop of the fault and its interpretation on east segment of KTNF.

图 10 伊吾周缘次级断裂分布图与野外照片

Fig. 10 Fault distribution around Yiwu and field photo.

图 11 a 喀尔里克山隆起的演化过程图解; b 演化过程对应各演化阶段的断层平面结构

Fig. 11 Block diagrams representing the building process of Karlik Tagh(a) and corresponding stages in plain view(b).

参考文献 30

[1]	柏美祥, 罗福忠, 李军, 等. 1999. 哈密盆地北缘活动断裂微地貌[J]. 内陆地震, 13(2): 162-168.
	BO Mei-xiang, LUO Fu-zhong, LI Jun, et al. 1999. Micro-geomorphology on the active northern margin fault zone of Hami Basin[J]. Inland Earthquake, 13(2): 162-168. (in Chinese)
[2]	邓起东, 冯先岳, 张培震, 等. 2000. 天山活动构造[M]. 北京: 地震出版社.
	DENG Qi-dong, FENG Xian-yue, ZHANG Pei-zhen, et al. 2000. Active Tectonics in Tianshan Mountains[M]. Seismological Press, Beijing. (in Chinese)
[3]	牛之俊, 游新兆, 杨少敏. 2007. 利用GPS分析天山现今地壳形变特征[J]. 大地测量与地球动力学, 27(2): 1-9.
	NIU Zhi-jun, YOU Xin-zhao, YANG Shao-min. 2007. Analysis of contemporary crustal deformation characteristic with GPS data of Tianshan Mountains[J]. Journal of Geodesy and Geodynamics, 27(2): 1-9. (in Chinese)
[4]	沈传波, 梅廉夫, 刘麟, 等. 2006. 新疆博格达山中新生代隆升-热历史的裂变径迹记录[J]. 海洋地质与第四纪地质, 26(3): 87-92.
	SHEN Chuan-bo, MEI Lian-fu, LIU Lin, et al. 2006. Evidence from apatite and zircon fission track analysis for Mesozoic-Cenozoic uplift thermal history of Bogda Mountain of Xinjiang, northwest China[J]. Marine Geology & Quaternary Geology, 26(3): 87-92. (in Chinese)
[5]	王琪, 丁国瑜, 乔学军, 等. 2000. 天山现今地壳快速缩短与南北地块的相对运动[J]. 科学通报, 45(14): 1543-1547.
	WANG Qi, DING Guo-yu, QIAO Xue-jun, et al. 2000. Recent rapid shortening of crust across the Tianshan Mts. and relative motion of tectonic blocks in the north and south[J]. Chinese Science Bullutin, 45(14): 1543-1547. (in Chinese)
[6]	王宗秀, 李涛, 张进, 等. 2008. 博格达山链新生代抬升过程及意义[J]. 中国科学(D辑), 38(3): 312-326.
	WANG Zong-xiu, LI Tao, ZHANG Jin, et al. 2008. The uplifting process of the Bogda Mountain during the Cenozoic and its tectonic implication[J]. Science in China(Ser D), 38(3): 312-326. (in Chinese)
[7]	吴富峣. 2016. 东天山东段几条主要断裂晚第四纪活动证据与变形机制[D]. 北京: 中国地震局地质研究所.
	WU Fu-yao. 2016. Late Quaternary activity of several main faults in east section of eastern Tian Shan and its implication on regional deformation mechanism[D]. Institute of Geology, China Earthquake Administration, Beijing. (in Chinese)
[8]	吴富峣, 冉勇康, 陈立春, 等. 2016. 东天山3条地震地表破裂带的展布及其与2次历史地震的关系[J]. 地震地质, 38(1): 77-90.
	WU Fu-yao, RAN Yong-kang, CHEN Li-chun, et al. 2016. Distribution of 3 earthquake rupture zones in eastern Tienshan and its relationship with 2 historical earthquakes[J]. Seismology and Geology, 38(1): 77-90. (in Chinese)
[9]	徐良鑫, 冉勇康, 梁明剑, 等. 2020. 新疆巴里坤1842年和1914年2次M7½历史地震地表破裂的几何展布及特征[J]. 地震地质, 42(1): 1-17. doi: 10.3969/j.issn.0253-4967.2020.01.001. DOI
	XU Liang-xin, RAN Yong-kang, LIANG Ming-jian, et al. 2020. Geometric distribution and characteristic of the surface rupture of two historical earthquakes in the Barkol Basin, Xinjiang[J]. Seismology and Geology, 42(1): 1-17. (in Chinese)
[10]	杨少敏, 李杰, 王琪. 2008. GPS研究天山现今变形与断层活动[J]. 中国科学(D辑), 38(7): 872-880.
	YANG Shao-min, LI Jie, WANG Qi. 2008. The deformation pattern and fault rate in the Tianshan Mountains inferred from GPS observations[J]. Science in China(Ser D), 38(7): 872-880. (in Chinese)
[11]	张培震, 邓起东, 杨晓平, 等. 1996. 天山的晚新生代构造变形及其地球动力学问题[J]. 中国地震, 12(2): 127-140.
	ZHANG Pei-zhen, DENG Qi-dong, YANG Xiao-ping, et al. 1996. Late Cenozoic tectonic deformation and mechanism along the Tianshan Mountains, northwestern China[J]. Earthquake Research in China, 12(2): 127-140. (in Chinese)
[12]	朱自虎, 季建清, 徐芹芹, 等. 2010. 新疆博格达-哈尔里克山晚新生代转换挤压性变形与隆起成山[J]. 地质科学, 45(3): 653-665.
	ZHU Zi-hu, JI Jian-qing, XU Qin-qin, et al. 2010. The Late Cenozoic transpressional deformation and uplift of Bogda-Harlic Mountains[J]. Chinese Journal of Geology, 45(3): 653-665. (in Chinese)
[13]	Bande A, Sobel E R, Mikolaichuk A, et al. 2015. Talas-Fergana Fault Cenozoic timing of deformation and its relation to Pamir indentation[J]. Geological Society, London, Special Publications, 427(1): 295-311. DOI URL
[14]	Biddle K T, Christie B N. 1985. Glossary-strike-slip deformation, basin formation and sedimentation[J]. SEPM. Special Publication, 68(4): 375-384.
[15]	Calais E, Vergnolle M, San’kov V, et al. 2003. GPS measurements of crustal deformation in the Baikal-Mongolia area(1994-2002): Implications for current kinematics of Asia[J]. Journal of Geophysical Research: Solid Earth, 108(B10): ETG14-1-ETG14-13.
[16]	Cunningham D. 2005. Active intracontinental transpressional mountain building in the Mongolia Altai: Defining a new class of orogeny[J]. Earth and Planetary Science Letters, 240(2): 436-444. DOI URL
[17]	Cunningham D, Mann P. 2007. Tectonics of strike-slip restraining and releasing bends[J]. Geological Society, London, Special Publications, 290(1): 1-12. DOI URL
[18]	Cunningham D, Owen L A, Snee L, et al. 2003. Structural framework of a major intracontinental orogenic termination zone: The easternmost Tienshan, China[J]. Journal of Geological Society, 160(4): 575-590. DOI URL
[19]	Cunningham D, Windley B, Dorjnamjaa D, et al. 1996. Late Cenozoic transpression in southwestern Mongolia and the Gobi Altai-Tien Shan connection[J]. Earth and Planetary Science Letters, 140(1-4): 67-81. DOI URL
[20]	Dewey J F, Holdsworth R E, Strachan R A. 1998. Transpression and transtension zones[J]. Geological Society, London, Special publications, 135(1): 1-14. DOI URL
[21]	Gu L X, Hu S X, Chu Q. 1999. Pre-collision granites and post-collision intrusive assemblage of the Kelameili-Harlik orogenic belt[J]. Acta Geological Sinica, 73(3): 316-329.
[22]	Harland W B. 1971. Tectonic transpression in Caledonian Spisbergen[J]. Geological Magazine, 108(1): 27-41. DOI URL
[23]	Hendrix M S, Dumitru T A, Graham S A. 1994. Late Oligocene-early Miocene unroofing in the Chinese Tianshan: An early effect of the India-Asia collision[J]. Geology, 22(6): 487-490. DOI URL
[24]	Jia Y, Fu B, Jolivet M, et al. 2015. Cenozoic tectono-geomorphological growth of the SW Chinese Tian Shan: Insight from AFT and detrital zircon U-Pb data[J]. Journal of Asia Earth Science, 111(1): 395-413.
[25]	Molnar P, Deng Q D. 1984. Faulting associated with large earthquakes and the average rate of deformation in central and eastern Asia[J]. Journal of Geophysical Research, 89(B7): 6203-6227. DOI URL
[26]	Shu L S, Charvet J, Lu H F, et al. 2002. Paleozoic accretion-collision events and kinematics of ductile deformation in the eastern part of the southern-central Tianshan belt, China[J]. Acta Geologica Sinica, 76(3): 308-323. DOI URL
[27]	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): ETG7-1-ETG7-32.
[28]	Vassallo R, Ritz J F, Bruacher R, et al. 2007. Transpressional tectonics and stream terraces of the Gobi-Altai, Mongolia[J]. Tectonics, 26(5): 1-8.
[29]	Zoback M L. 1992. Frist- and second-order patterns of stress in the lithosphere: The world stress map project[J]. Journal of Geophysical Research: Solid Earth, 97(B8): 11703-11728.
[30]	Zubovich A V, Wang X Q, Scherba Y G, et al. 2010. GPS velocity field for the Tien Shan and surrounding regions[J]. Tectonics, 29(6): 250-272.