福建省早三叠世溪口期岩相古地理与构造活动性质

Lithofacies-palaeogeography and Structural Active Charaters of Xikou Stage of Early Triassic in Fujian Province

本文根据福建省溪口组岩石组合类型、沉积构造、生态组合类型、粘土岩微量元素等沉积特征,对溪口期沉积水体的古水深、古流向以及沉积相的展布进行了分析,认为溪口期早时自南东往北西依次分布有潮坪泻湖相、台地边缘浅滩相、台地前缘斜坡相和陆棚边缘盆地相;溪口期晚时沉积相单一为潮坪泻湖相分布,可细分为潮坪亚相和泻湖亚相。同时对控制沉积盆地的同沉积期构造的活动性质和构造背景作了探讨,认为沉积盆地的形成与发展是板块扩张下陆内地块裂陷的产物。

Based on the sedimentary characters of Xikou Formation (T_1) such as the lithological types,sedi-mental structures,ecological assemblages and trace elements in clayrock,an analysis is herein made onthe palaeowaterbody depth,palaeocurrent direction and sedimental facies distribution during XikouStage.During early Xikou Stage there is a distribution of four sedimental facies from southeast to north-west in Fujian Province,e.i.the wadd lagoon,platform-maginal shoal,platform foreslope and shelf-margin basin,and during late Xikou Stage only the wadd lagoon facies is in existence which can be di-vided into both the wadd and lagoon subfacies.After studying the active characters and setting of struc-tures in the syndepositional stage that control the development of sedimental basin,the author consideredthat the formation and development of the sedimental basin result from the rifting of intercontinentalmassifs under the condition of plate spreading.