中国河北柳江盆地西部构造演化及前陆盆地规律研究

Study on Tectonic Evolution and Foreland Basin Laws in the Western Part of Liujiang Basin, Hebei Province, China

摘要: 本文根据柳江盆地西部地震剖面制作演化过程剖面，演化剖面显示柳江盆地西缘奥陶系顶底板存在大规模顺层滑脱，整体形成坡坪式构造，以形成薄皮逆冲推覆构造为主要特征。演化次序整体上呈现后展式结构，体现了深部推动能量“由深到浅”的过程，很可能是响山岩体阶段性两期隆升诱发的向东水平推移所导致的逆冲推覆构造。剖面的恢复显示深层寒武系地层向东推移距离超过4.5 km，预计整体水平推移距离可达到8~9 km左右，相对于现今响山岩体和柳江盆地东西尺度都为15 km左右而言，可谓之“大规模”推覆，水平推移导致大量物质迁移、叠置及造山隆升剥蚀，说明柳江盆地西部吴庄地区属于小型“造山带”。演化阶段体现其白垩纪成盆期为前陆盆地属性，和侏罗纪负向火山岩构造盆地相区别。柳江盆地西缘也埋藏有大规模的绥中花岗岩，说明柳江盆地可能是在大范围绥中花岗岩上发育的碟形盆地。

Abstract: Based on the seismic profile in the western part of the Liujiang Basin, this paper fabricates an evolutionary process profile. The evolutionary profile shows that there is a large-scale subduction of the top and bottom plates of the Ordovician on the western margin of the Liujiang Basin, and the overall structure forms a sloping structure, with the main feature being the formation of thin-crust thrust and overlying structures. The evolutionary sequence as a whole presents a posteriorly spreading structure, reflecting the process of deep driving energy “from deep to shallow”. It is very likely to be a thrust overlying structure caused by the eastward horizontal movement induced by the two-stage uplift of the Xiangshan rock mass. The restoration of the profile shows that the deep Cambrian strata have moved eastward by more than 4.5 kilometers. It is estimated that the overall horizontal movement distance can reach about 8~9 kilometers. Compared with the current Xiangshan rock mass and the Liujiang Basin, both with an east-west scale of about 15 kilometers, this can be regarded as a “large-scale” overthrust. The horizontal movement has led to a large amount of material migration, superposition and orogenic uplift erosion. It indicates that the Wuzhuang area in the western part of the Liujiang Basin belongs to a small “orogenic belt”. The evolutionary stage indicates that its Cretaceous basin-forming period has the attribute of a foreland basin, which is distinct from the Jurassic negative volcanic rock tectonic basin. There are also large-scale Suizhong granites buried on the western edge of the Liujiang Basin, indicating that the Liujiang Basin might be a dish-shaped basin developed on a large area of Suizhong granites.