MESO-CENOZOIC TECTONIC EVENTS AND STRUCTURAL CONSTRAINTS IN THE SOUTHERN JUNGGAR BASIN: EVIDENCE FROM DETRITAL COMPOSITIONS
Fang Shihu1, Jia Chengzao1, Song Yan1, Guo Zhaojie2, Yuan Shuwu3, Wang Xulong3
1. Research Institute of Petroleum Exploration and Development of China, Beijing 100083; 2. School of Earth and Space Sciences, Peking University, Beijing 100871; 3. Xinjiang Oilfield Branch Company, China National Petroleum Corp., Karamay, Xinjiang 834000
The conglomerates of widespread distribution suggested active tectonisms during the Late Jurassic-Earliest Cretaceous,Late Cretaceous and Late Cenozoic.The framework grains of the Jurassic-Cenozoic sandstones and conglomerates in the southern Junggar Basin generally showed low detrital maturity,which mainly resulted from tectonic activities and orogenesis of the provenance area,namely,the ancestral Tianshan.The supplied provenance consisted of provenances of metamorphic rocks,acidic volcanics and sedimentary rocks attributed to recycled orogen, magmatic-arc and arc orogenic sandstone types.The detrital compositions suggested some differences in provenance between the western segment and the eastern segment of the southern Junggar Basin,which showed different sandstone types and tectonic attributes,especially the relative increasing of sedimentary rock detritus suggesting the uplifting and denudation of sedimentary rocks along southern margin of the basin.Different heavy mineral assemblages and unstable heavy minerals during the Late Jurassic-Earliest Cretaceous,Late Cretaceous and Late Cenozoic,indicated tectonic activities during these three stages.The characteristics of sedimentary systems and petrology proved that the basin-orogen pattern changed three times corresponding to the three stages mentioned-above,respectively.The formation of petroleum systems were controlled by the three tectonic events,matching with the multi-phase hydrocarbon accumulation and adjustment events in pool forming.
Fang Shihu,Jia Chengzao,Song Yan et al. MESO-CENOZOIC TECTONIC EVENTS AND STRUCTURAL CONSTRAINTS IN THE SOUTHERN JUNGGAR BASIN: EVIDENCE FROM DETRITAL COMPOSITIONS[J]. Chinese Journal of Geology, 2007, (4): 753-765.