含富锂(钾)卤水断陷盆地的深部构造特征:以中国华南吉泰盆地为例

Deep Structural Characteristics of Depressional Basin with Lithium(Potash)-Rich Brines:An Example of Jitai Basin in South China

中国华南吉泰盆地在白垩纪-古近纪发育大量蒸发岩,其中含富锂卤水矿床,由于盆地深部构造特征认识不清,导致富锂卤水矿勘查评价明显滞后.基于盆地东北部泰和坳陷二维地震数据和钻孔资料,经过精细保幅处理和综合构造解释,总结了含富锂卤水矿断陷盆地的深部构造特征.地震剖面和构造属性表明,盆地深部发育错断白垩系的NE-SW走向、NW倾向的正断层,高陂-梅岗低隆起深部存在挤压走滑性质逆断层,二者导致盆地白垩系茅店组、周田组和宏岗组微裂隙普遍发育.基于梅岗含富锂卤水矿层位追踪和钻孔岩性录井,吉泰盆地深部隐伏正断层和白垩系裂隙是深层富锂卤水向上运移的通道,白垩系深层可能存在富锂卤水矿床.

Massive Cretaceous-Paleogene evaporates with lithium(potash)-rich brines develop in Jitai Basin of South China,of which deep structural characteristics remain unclear so that no breakthrough progress has been made in the exploration and evaluation of brines.According to 2 D seismic survey and drilling in Taihe Depression,it summarizes structural pattern and characteristics of the brine-bearing basin by means of refined relative-amplitude-preserved seismic processing and integrated interpretation.Seismic profiles and structural attributes show that one NE-SW normal fault southward sloping down to the basin basement and inner strike-slipping faults in low uplift of Gaopi-Meigang lead to more fractures yielded within Maodian,Zhoutian and Honggang formations.By the reservoir tracking to Meigang lithium-bearing brines and the lithological analysis,it is concluded that the normal fault and the fractures form migration pathways of deep brines moving upward.Meanwhile,much of lithium-rich brines can be predicted within deep Cretaceous strata.