Structure and Geological Significance of Pishan Caldera in Tarim Basin

摘要/Abstract

摘要： On the basis of caldera theory integrated with seismic-lithofacies interpretation and tectonic evolution, the paper investigates the structures of Pishan caldera and describes its impact on the Cretaceous reservoirs. It is considered that the large-scaled composite caldera in Pishan formed in the late Hercynian movement, which is a circle with the diameter of 25 km and the maximum subsidence depth of 1.5 km. Volcanic materials erupted in central and fissure mode along the circular fault and the evacuation of magma chamber resulted in sharply subsidence. Volcanic eruption facies, lacustrine facies and Cretaceous breccia facies assume the circular symmetric distribution; inner-dipping circular normal faults and outer-dipping circular inverse faults are developed in collapse structure area and high-steep divergent inverse faults occur in central dome structure area, which indicates the complete process of caldera from its first eruption, subsidence to re-activation.Pishan caldera structure controls the development and distribution of the Cretaceous reservoirs.

关键词: Tarim basin, Pishan, caldera, circular fault, Cretaceous

Abstract: On the basis of caldera theory integrated with seismic-lithofacies interpretation and tectonic evolution, the paper investigates the structures of Pishan caldera and describes its impact on the Cretaceous reservoirs. It is considered that the large-scaled composite caldera in Pishan formed in the late Hercynian movement, which is a circle with the diameter of 25 km and the maximum subsidence depth of 1.5 km. Volcanic materials erupted in central and fissure mode along the circular fault and the evacuation of magma chamber resulted in sharply subsidence. Volcanic eruption facies, lacustrine facies and Cretaceous breccia facies assume the circular symmetric distribution; inner-dipping circular normal faults and outer-dipping circular inverse faults are developed in collapse structure area and high-steep divergent inverse faults occur in central dome structure area, which indicates the complete process of caldera from its first eruption, subsidence to re-activation.Pishan caldera structure controls the development and distribution of the Cretaceous reservoirs.

Key words: Tarim basin, Pishan, caldera, circular fault, Cretaceous

ZHANG Changjian, LIU Shaojie, LUO Shaohui, WANG Ming. Structure and Geological Significance of Pishan Caldera in Tarim Basin[J]. 新疆石油地质, 2016, 37(zk(English) ): 20-24.

ZHANG Changjian, LIU Shaojie, LUO Shaohui, WANG Ming. Structure and Geological Significance of Pishan Caldera in Tarim Basin[J]. Xinjiang Petroleum Geology, 2016, 37(zk(English) ): 20-24.

参考文献

[1] CUI Zehong,TANG Yue.Geochemical characteristics and geological significance of later Hercynian volcanic rocks in Tahe area[J].Geology in China,2010,37(2):334-345.
[2] KANG Yuzhu.Characteristics of the Carboniferous-Permian volcanic rocks and hydrocarbon accumulations in two great basins,Xinjiang area[J].Petroleum Geology &Experiment,2008,30(4):321-327.
[3] LUO Jinhai,CHE Zicheng,CAO Yuanzhi,et al.Geochemical and geochronological characteristics and its tectonic significance of Early Permian acid volcanic rocks of Xiaotikanlike formation in thesouthern margin of South Tianshan orogen,NW China[J].Acta Petrologica Sinica,2008,24(10):2 281-2 288.
[4] YANG Jinlong,LUO Jinglan,HE Faqi,et al.Permian volcanic reservoirs in the Tahe region[J].Petroleum Exploration and Development,2004,31(4):44-47.
[5] TANG Liangjie,HUANG Taizhu,QIU Haijun,et al.The tectonic characteristics and hydrocarbon accumulation of late Hercynian volcanic rocks in the Tahe area,Tarimbasin[J].Acta Geologica Sinica,2012,86(8):1 188-1 197.
[6] WEN Shengming,WANG Jianzhong,WANG Guizhong,et al.Characteristics of igneous rock reservoir and its influence on hydrocarbon accumulation,Tarim basin[J].Oil Geophysical Prospecting,2005,40(Supp.):33-39.
[7] RUAN Honghong,XIE Jiaying,TAO Kuiyuan.Circular mega volcanic structure in Kuocangshan &its geological significance[J].Volcanology &Mineral Resources,1993,14(4):1-11.
[8] LU Jiang,LI Zubin.The geological characteristics and evolving history of Wangweishan caldera,Deqing[J].Geology of Zhejiang,1988,4(2):7-12.
[9] WU Yan.Lishui tectono-volcanic depression-its volcanic structure types and evolution model[J].Bull.Nanjing Inst.Geol.M.R.,Chinese Acad.Geol.Sci,1982,3(1):57-77.
[10] HE Dian,LI Jianghai,LIU Shoujie,et al.Discovery of a giant caldera in the Yingcheng formation in the Xujiaweizi fault depression,northern Songliao basin[J].Geology in China,2008,35(3):463-470.
[11] LÜHaitao,ZHANG Zhongpei,SHAO Zhibing,et al.Structural evolution and exploration significance of the Early Paleozoic palaeouplifts in Bachu-Maigaiti area,the Tarim basin[J].Oil &Gas Geology,2010,31(1):76-83.
[12] LIPMAN P W.Subsidence of ash-flow calderas:relation to caldera size and magma-chamber geometry[J].Bulletin of Volcanology,1997,59(3):198-218.
[13] ZHANG Zhongpei,LIU Shilin,YANG Ziyu,et al.Tectonic evolution and its petroleum geological significances of the Maigaiti slope,Tarim basin[J].Oil &Gas Geology,2011,32(6):909-919.
[14] CHEN Gang,TANG Liangjie,YU Tengxiao,et al.Differential deformation and control mechanism of fault structures in Yubei area of Tarim basin[J].Journal of Earth Sciences and Environment,2015,37(3):42-65.