四川类前陆盆地须家河组震积岩的发现及其研究意义

四川盆地是扬子地块上的一个多旋回类前陆盆地，盆地边缘长期剧烈的构造活动控制着上三叠统须家河组的沉积作用。通过地表剖面和岩芯观察，首次在该盆地上三叠统须家河组地层中识别出微裂缝、微褶皱层、JP2]微断层、液化砂岩构造、球—枕构造和角砾岩等典型的软沉积变形构造的地质记录，这些变形构造可能与印支构造运动期的地震活动有关。越靠近断裂带附近，软变形构造呈明显增加的趋势，表明震积岩的分布与龙门山和米仓山—大巴山构造活动有关。因此，研究该盆地须家河组震积岩，对了解控制盆地边界的龙门山和米仓山—大巴山造山带的活动史具有重要意义。

The Discovery and Significance of Seismites from Xujiahe Formation in Sichuan Analogous Foreland Basin

The sedimentary processes of the Upper Triassic Xujiahe Formation were controlled by the long term tectonic activity in the peripheral zones of Sichuan basin, a mult episodic para foreland basin of the Yangtze block. Based on the outcrop and the core observations, a series of soft sedimentary deformation structures were recognized for the first time in the Triassic Xujiahe formation in Sichuan Basin; these structures include micro cracks, micro folds, micro faults, liquefied sand structure, ball and pillow structures and eautochthnous breccias, and so on. These autochthonous structures are here suggested to having been formed related to seismic activity during Indosinian tectonic episode. The increase in abundance of these soft deformation structures towards the outer peripheral zone of the basin to the west and north respectively suggests a causal connection to the overthrusting of Longmenshan to the west and Micangshan Dabashan to the north fold thrust belts, Therefore, to a broader extent, this study is of great significance for us to understand the tectonic history of Sichuan basin and adjacent Longmenshan and Micangshan Dabashan fold thrust belts.