广西中—晚泥盆世拉利和四红山剖面的碳酸盐岩微相和牙形石生物地层格架  

THE MIDDLE–LATE DEVONIAN SEDIMENTARY MICROFACIES AND CONODONT BIOSTRATIGRAPHY IN THE SIHONGSHAN AND LALI SECTIONS,GUANGXI

作　　者：安晏庆 张欣松 杜伟东 AN Yan Qing;ZHANG Xin Song;DU Wei Dong(Zijin College of Geology and Mining,Fuzhou University,Fuzhou 350108)

机构地区：[1]福州大学紫金地质与矿业学院,福建福州350108

出　　处：《地层学杂志》2024年第2期147-171,共25页Journal of Stratigraphy

基　　金：国家自然科学基金(42002017)资助。

摘　　要：华南中—上泥盆统碳酸盐岩高度发育,但却缺乏系统碳酸盐岩微相研究。广西都安四红山剖面和宜州拉利剖面的中—上泥盆统连续发育,是华南泥盆系重要的参考剖面。中—晚泥盆世,四红山剖面为斜坡—盆地相,而拉利剖面为台地—盆地相。本文重建了这两条剖面中—上泥盆统牙形石生物地层,在此基础上结合碳酸盐岩微相沉积学研究,恢复了它们同时期沉积环境演变过程,为不同地层单元的区域对比提供了可靠依据。在吉维特期和弗拉期FZ1~FZ4期,四红山剖面主要为分水岭组硅质灰岩及“榴江组”钙质泥岩,拉利剖面主要为老爷坟组礁灰岩。而在弗拉期牙形石带FZ5~FZ8期间,两条剖面均因海侵事件造成台地淹没形成五指山组,主要特征为大化石稀少的微晶/瘤状/泥质条带灰岩,本次海侵可以与全球Middlesex事件相对应。此外中—晚泥盆世一系列生物环境事件,如F-F事件可通过牙形类的种群更替得以识别。The Middle–Upper Devonian carbonate rocks in South China are highly developed.However,systematic study on the carbonate microfacies is lacking.The Middle–Upper Devonian strata are developed continuously in the Sihongshan section in Du’an and the Lali section in Yizhou,Guangxi,SW China,and they are important reference sections of the Devonian system in South China.The Middle–Late Devonian in the Sihongshan section is a slope-basin facies,and in the Lali section is a platform-basin facies.In this paper,the Middle–Upper Devonian conodont biostratigraphy at the two sections was established,based on which the sedimentology of the carbonate microfacies was studied,the evolutionary course of the sedimentary environment in the same period was reconstructed,so as to provide a reliable basis for the regional comparison among different stratigraphic units.In the Givetian and Frasnian FZ1–FZ4,the Sihongshan section shows mainly siliceous limestone in the Fenshuiling Formation and calcareous mudstone in the“Liujiang Formation”,while the Lali section exposes reef limestone in the Laoyefen Formation.In the Frasnian FZ5–FZ13,the Wuzhishan Formation was formed in both sections,presenting mainly micritic/nodular/mud-banded limestone with few large fossils due to the platform drowning in a transgression event that corresponds to the global Middlesex Event.In addition,a series of bio-events in the Middle–Late Devonian such as F-F event could be identified based on the population change of conodonts.

关 键 词：吉维特阶 弗拉阶 广西 泥盆纪 沉积微相 牙形类 

分 类 号：P534.44[天文地球—古生物学与地层学]