摘要
川东北开县满月甘泉剖面长兴组早期发育两期生物丘,分别位于两个向上变浅的沉积旋回中上部。通过露头解剖、镜下鉴定和X衍射等手段,对该剖面生物丘构成进行精细研究发现:第一期生物丘在角砾灰岩的基础上发育,造丘生物以蓝绿藻为主;岩性为泥晶灰岩和含云灰岩;由丘基和丘核构成。第二期生物丘在生物碎屑滩的基础上发育,造丘生物早期主要为蓝绿藻和粗枝藻,后期以各类海绵和珊瑚为主;岩性为泥—微晶灰岩,局部白云岩化;发育丘基、丘核和丘顶,最终向礁骨架演化。在此基础上,探讨了两期生物丘成丘模式:前者属于低能生物丘,形成于台缘前斜坡相带内,经历了两个演化阶段;而后者属于高能生物丘,形成于台地边缘生物礁滩相带内,经历了四个演化阶段。
Two phases of bioherms are respectively developed in the middle-upper of two descending cycles in the forepart of Changxing Formation in Manyue-Ganquan section of Kaixian, northeastern Sichuan. By the outcrop survey- ing, observation by microscope and diffraction of X-ray, the composition of bioherms is researched in detail. It is found that the first phase of bioherm in which the bioherm-building organisms are dominated by eyanobaeteria and the lithology includes micrites and dolomitised limestone is composed of bioherm-bottom and bioherm-core. The second phase of bioherm in which the bioherm-building organisms are dominated by algae primarily and types of sponges and corals later and the lithology includes mierites with partly dolomitation is composed of bioherm-bottom, bioherm-core and bioherm-top and turns to reef finally. Based on that, the bioherm-forming models of two bioherms are discussed ： the former which develops on the platform margin shoal-slope is low energy bioherm and has two phases of evolvement, while the latter which develops on the platform-margin shoal and reef is high energy bioherm and has four phases of evolvement.
出处
《沉积学报》
CAS
CSCD
北大核心
2009年第1期9-17,共9页
Acta Sedimentologica Sinica
基金
教育部构造与油气资源重点实验室开放基金项目(批准号:YQ2006KF18)
中国石油化工集团公司项目(编号:2006026015)
中国石油化工集团公司前瞻性项目专题(编号:2007026230)联合资助
关键词
生物丘
成丘模式
长兴组
川东北
bioherm, bioherm-forming model, Changxing Formation, Northeast Sichuan
