Early Cretaceous fault-depression development characteristics of western Tabei sag, Erlian Basin
CHEN Nian-Nan1,2(), LI Man-Gen1,2(), GUAN Bao-Wen1,2, SONG Zhi-Jie1,2, DUAN Jian-Bing1,2, LI Xi-De3, LIU Wu-Sheng3, LIU Ying1,2, FAN Peng-Fei1,2
1. School of Earth Sciences,East China University of Technology,Nanchang 330013,China 2. State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China 3. Beijing Research Institute of Uranium Geology,Beijing 100029,China
This study restored the balanced cross sections of the Tabei sag and calculated the extension amounts and extension rates of the sag using three typical seismic profiles selected from the western Tabei sag,Erlian Basin using the 2D Move software.Then,it analyzed the geological and tectonic evolution characteristics of the Tabei sag since the Early Cretaceous.The results indicate that:(1)Due to the effects of the main normal fault layer on the northwest side,the whole Tabei sag has evolved into a single-faulted dustpan-shaped faulted lake basin that is faulted in the west and is overlapped in the east.Moreover,it consists of a fault in the lower part and a depression in the upper part vertically.(2)The variation characteristics of the extension amounts and extension rates in each period of the Tabei sag match the tectonic evolution process of the sag,and all of them show a strong to weak trend,indicating that the extension in the Tabei sag is in a weak-strong-weak trend.(3)The Tabei sag mainly underwent four tectonic movements:①During the sedimentary period of the Aershan Formation,the faults in the Tabei sag began to develop,the sag subsided under the control of normal fault activities, and the Tabei sag began to take shape.②During the sedimentary period of the Tenggeer formation,the faults inside the sag continued to develop,and the whole sag was significantly controlled by the fault depression.The extension amount and extension rate gradually increased and reached their peaks during the upper Tenggeer formation.③During the sedimentary period of the Saihan formation,the Tabei sag was slightly affected by faults overall,and the sedimentary center was gradually far away from the main fault. During this period, the Tabei sag was characterized by depression,subsidence,and overlap unconformity.④Since the end of the Saihan formation,the fault depression activities have disappeared,the basin has gradually contracted, and the terrain has tended to be flat.Since then,the Tabei sag has been continuously uplifting.
陈念楠, 李满根, 关宝文, 宋志杰, 段建兵, 李西得, 刘武生, 刘颖, 范鹏飞. 二连盆地塔北凹陷西部早白垩世断—坳发育特征研究[J]. 物探与化探, 2022, 46(5): 1149-1156.
CHEN Nian-Nan, LI Man-Gen, GUAN Bao-Wen, SONG Zhi-Jie, DUAN Jian-Bing, LI Xi-De, LIU Wu-Sheng, LIU Ying, FAN Peng-Fei. Early Cretaceous fault-depression development characteristics of western Tabei sag, Erlian Basin. Geophysical and Geochemical Exploration, 2022, 46(5): 1149-1156.
Zhao Y, Xu Q, Liang Y P, et al. Uranium mineralization characteristics of Cretaceous period and prospecting direction of the Hurenbuqi depression in Erlian basin,Inner Mongolia[J]. Geology in China, 2018, 45(1): 168-177.
Guo H W. Studies on characteristics and regularity of metallogenesis of Bayanwula uranium deposits,Inner Mongolia[D]. Beijing: China University of Geosciences(Beijing), 2014.
Cheng S Y, Liu S F, Su S, et al. Structural characteristics analysis of Saihantala sag in Erlian Basin[J]. Oil Geophysical Prospecting, 2011, 46(6):961-969.
Wang X, Li L, Yu Y, et al. Study on paleogeomorphic restoring and structural development history of Wulanhua sag,Erlian Basin[J]. China Petroleum Exploration, 2013, 18(6):62-68.
[5]
梁越. 二连盆地巴音都兰凹陷构造特征及演化研究[D]. 北京: 中国地质大学(北京), 2015.
[5]
Liang Y. Tectonic characteristics and tectonic evolution of Erlian Basin Bayindulan depression[D]. Beijing: China University of Geosciences(Beijing), 2015.
Xu Q. Structural control of sedimentary-type uranium mineralization and analogue modelling—A case study of Naomugen and Hurenbuqi sag[D]. Xuzhou: China University of Mineing & Technology, 2018.
[7]
鲁超. 二连盆地巴彦乌拉铀矿田构造控矿机制和成矿模式[D]. 武汉: 中国地质大学, 2019.
[7]
Lu C. Tectonic ore-controlling mechanism and uranium metallogenic model of Bayanwula uranium ore field in Erlian Basin[D]. Wuhan: China University of Geosciences, 2019.
Qi J F, Zhao X Z, Li X P, et al. The distribution of early cretaceous faulted-sags and their relationship with basement structure within Erlian Basin[J]. Earth Science Frontiers, 2015, 22(3):118-128.
Liu W S, Li B H, Shi Q P, et al. Model and application of radon anomaly in soil of sandstone type uranium deposits in Erlian Basin[J]. Geophysical and Geochemical Exploration, 2015, 39(2):234-239.
[11]
刘波. 二连盆地巴赛齐含铀古河谷构造建造与铀成矿模式研究[D]. 长春: 吉林大学, 2018.
[11]
Liu B. Study of structure and construction in uranium-bearing paleo-valley and uranium metallogenic models in the Basaiqi Area, Erlian Basin[D]. Changchun: Jilin University, 2018.
[12]
Guo Z, Shi Y, Yang Y, et al. Inversion of the Erlian Basin (NE China) in the early Late Cretaceous: Implications for the collision of the Okhotomorsk Block with East Asia[J]. Journal of Asian Earth Sciences, 2018, 154:49-66.
doi: 10.1016/j.jseaes.2017.12.007
Zhang T, Zhu W L, Zhong K, et al. Tectonic characteristics and extensional compressional rates of the Northeast Sag of South Yellow Sea Basin[J]. Marine Geology & Quanternar Geology, 2021, 41(2):118-125.
