蒙古国塔木察格盆地塔南凹陷下白垩统构造层序地层学的初步研究A Preliminary Study on Tectonic Sequence Stratigraphy for the Lower Cretaceous in the Tanan Sag, Tamsag Basin, Mongolia
孙效东, 刘赫, 李春柏, 吴根耀, 李强, 张革, 高庚, 朱德丰, 王金奎, 刘绍军
构造层序地层, 层序界面, 层序结构, 同生断层, 下白垩统, 塔南凹陷, 塔木察格盆地Tectonic Sequence Stratigraphy, Sequence Interface, Sequence Structure, Contemporaneous Faulting, Lower Cretaceous, The Tanan Sag, The Tamsag Basin
《Advances in Geosciences》, Vol.4 No.2, 2014-04-18
Based on the drilling data, seismic reflecting horizons, together with sedimentological achievements, in the light of the tectonic sequence stratigraphy, the sequences in the Lower Cretaceous of the Tanan Sag are studied and discriminated. The Tongbomiao Formation, as deposits of the initial rifting stage and being divided into two members lithologically, is correlated to two third-order sequences (SQ1 and SQ2). The Nantun Formation, record of the main rifting stage, is correlated to third-order sequence SQ3, in which three forth-order sequences (Sq31, Sq32 and Sq33), and furthermore, seven fifth-order sequences, are identified. The superface of Sq32 represents the largest lacustrine overflow, which marks blossom phase of the basin developing, and the seven suborder tectonic units formed during this period. The Damoguaihe Formation, as deposits of the stage from fault-depressing to down-warping, is correlated to third-order sequence SQ4, in which two forth- order sequences are identified. The Yimin Formation, record of down-warping stage, is correlated to third-order sequence SQ5. The contemporaneous faulting plays an important role in the sequence developing, which can be separated into three grades and two systems. The NE-orientated normal faulting activates during sedimentary period of the Tongbomiao and Nantun Formations, which results in the containing space enlarged on the upper side. The strike-slip (or transtensile) faulting, with NEN-striking or approximate longitude-striking, moves during sedimentary period of the Damoguaihe Formation and lower part of the Yimin Formation. Vertically, the both fault systems are bounded by the T22 seismic reflecting horizon (the top surface of Nantun Formation).