| 库车坳陷北缘早白垩世源区特征:来自盆地碎屑锆石 |
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| 引用本文： | 彭守涛.库车坳陷北缘早白垩世源区特征:来自盆地碎屑锆石[J].沉积学报,2009,27(5):956-966. |
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| 作者姓名： | 彭守涛 |
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| 作者单位： | 中国石油化工股份有限公司石油勘探开发研究院北京100083 |
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| 摘 要： | 通过对下白垩统亚格列木组79颗碎屑锆石的LA—ICP—MS U—Pb微区定年分析，结果表明该时期库车坳陷的物源年龄构成复杂，主要集中在427~389 Ma，379~339 Ma、321~283 Ma，266~239 Ma，162~150 Ma五组及前寒武纪基底年龄。结合对潜在的物源区天山造山带岩石属性、年龄构成调研以及以往盆地碎屑组分、重矿物研究成果，作者认为早白垩世时期库车坳陷北缘物源受南天山皱褶带和伊犁—中天山弧造山带源区共同控制，即南天山、塔里木北缘的南天山花岗岩—碱性岩带，伊犁—中天山(包括中天山南缘断裂的古生代花岗岩—火山岩带)均为潜在的物源。并且，前寒武纪基底年龄的发现反映源区剥露程度较深，天山造山带可能存在元古代—太古代结晶基底，但对此类锆石的成因机理尚需进一步研究。另外，碎屑锆石年龄162~150 Ma暗示了天山地区可能存在晚侏罗世岩浆活动，但有待进一步的证实。
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| 关 键 词： | 库车坳陷天山白垩系碎屑锆石物源 |
| 收稿时间： | 1900-01-01 |
Provenance of Early Cretaceous Deposites in Kuqa Subbasin,the Southern Margin of Tianshan: Implication from Detrital |
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| Institution: | .Institute of Exploration & Development, SINOPEC, Beijing 100083 |
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| Abstract: | There are some quite different disputes about the provenance types and tectonic attributes of early Cretaceous deposits in Kuqa Subbasin, northern margin of the Tarim Basin, with very complicated source rocks. In order to reveal further detailed information on the nature of the source terrains, a typical sandstone samples from the Yageliemu Formation in early Cretaceous strata is collected for U Pb dating of 79 detrital zircons. The lower Cretaceous sample shows a complicated provenance geochronological constitution, with new peak ages of 427~389 Ma, 379~339 Ma, 321~283 Ma, 266~239 Ma, 162~150 Ma and some Precambrian basement zircons. Investigating on the rock attributes and age constitution of the Tian Shan Orogen, the potential source area, together with the previous results of sandstone framwork grains and detrital heavy minerals in Kuqa Subbasin, we suggest that the provenance supply is mainly resulted from denudation process of the South Tian Shan, the granite alkaline rocks belts in South Tian Shan and Yili Central Tian Shan (including the Paleozoic granites and vocanic rocks at the southern margin of the Central Tian Shan)，related to the Middle Late Jurassic volcanism and the Ordovician Permian tectonic events. Additionly，the several clusters of Proterozoic Archean ages of this sample probably reflect that some provenance areas were deeply exhumated and the Archean Proterozoic basement maybe exsist in the Tian Shan Orogen. In addition，the detrital zircons age spectra of 162～150Ma indicates that there was possible magma activity in late Jurassic in Tian Shan area, which require further work. |
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