四川盆地北部长兴组-飞仙关组礁、滩分布及其控制因素

Distribution and controlling factors of reefs and oolitic beaches for the Changxing to Feixianguan formations in the northern Sichuan basin

本文对四川盆地北部长兴组礁和飞仙关组滩特征和分布及其控制因素作了较为深入的探讨,研究认为生物礁为海平面上升过程中形成的海侵礁,其在纵向上的分布主要位于长兴期中晚期;鲕粒滩主要是在区域海平面下降过程中形成的海退滩,其在纵向上位于飞一—飞三。礁、滩在平面上主要在广元—梁平海槽两侧呈带状分布。长兴期随着海平面的上升生物礁向海侵的方向迁移,并且其层位逐渐抬升。飞仙关期随着海平面的下降,滩向海槽中迁移,其分布层位也有逐渐抬高的趋势。控制这套地层礁、滩发育的主要因素有海平面升降、大地构造、同生断裂及古气候。

This paper relatively intensively discusses the characteristics, distribution and controlling factors of reefs of the Changxing Formation and beaches of the Feixianguan Formation in the northern Sichuan basin. It is thought that： the reefs are transgressive reefs formed during the regional sealevel rise and vertically mainly distributed in the middle and upper parts of the Changxing Formation, and the oohtic beaches mare mainly regression beaches developed in the process of regional sea-level fall and vertically distributed in Members 1 to 3 of the Feixianguan Formation. In a plan view, reefs and beaches mainly occur in zones on both sides of the Guangyuan-Liangping sea trough. In the period of Changxing, with the rise of sea level reefs moved in the direction of transgression and their horizon was gradually uplifted; in the Feixianguan period, with the fall of sea level the beaches migrated toward the trough and their horizon had a trend of gradual rise. The main factors that controlled the formation and development reefs and beaches of the strata are sea-level fluctuation, tectonics, contemporaneous faults and paleoclimate.