四川广安谢家槽三叠系底部微生物岩中化石微囊菌的首次发现及其意义  

THE FIRST DISCOVERY OF FOSSIL MICROCYSTIS FROM THE BOTTOM OF THE LOWEST TRIASSIC AT THE XIEJIACAO SECTION, GUANG’AN, SICHUAN

作　　者：周志澄[1] 罗辉[1] ZHOU Zhicheng;LUO Hui(Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,China)

机构地区：[1]中国科学院南京地质古生物研究所,南京210008

出　　处：《微体古生物学报》2022年第3期235-244,共10页Acta Micropalaeontologica Sinica

基　　金：国家自然科学基金项目(42172028);中国科学院战略性先导科技专项(XDB26000000);第二次青藏高原综合科学考察(2019QZKK0706)共同资助。

摘　　要：现生微囊菌主要生活在河流、湖泊和水库等淡水水体中,在四川广安剖面下三叠统夜郎组底部微生物岩中,作者首次在海相沉积中发现了微囊菌化石,文中对微囊菌化石进行了详细描述,并与现生淡水微囊菌进行了对比研究。它类似于现代的鱼害微囊菌(Microcystis ichthoblabe)。此外,作者在岩石薄片中还首次发现了与化石微囊菌共存的暗色泥晶碳酸盐团块,其中产有大量的微囊菌菌苗。本文所报道的化石微囊菌产于海相沉积中,我们可以推测,这些携带着大量微囊菌菌苗的泥晶碳酸盐团块可能最初由河流或其他淡水流入海洋,在适当的环境下,微囊菌大量繁殖。同时,微囊菌化石的发现表明,这一地区早三叠世海洋地球化学条件、沉积环境及后来的成岩作用有利于蓝细菌化石的保存。Present Microcystis live in the fresh waters like rivers, lakes and reservoirs so on. Microcystis fossils were first discovered in the microbialite from the bottom of the Lowesr Triassic Yelang formation at the Xiejiacao section of Guang’an, Sichuan. Their morphology and structural characteristics are similar to those of present Microcystis ichthoblabe. Moreover, a mass of barely visible Microcystis vaccines have been found in the dark micritic lumps. This discovery discloses the secret about the origin of the Early Triassic Microcystis. Probably, at the beginning these micritic lumps with Microcystis vaccines formed in the fresh waters such as the rivers and emptied into the sea later. Occurrence of the well-preserved Microcystis fossils indicates that conditions of marine geochemistry, depositional environments and diagenesis later are benefit to calcification and preservation of cyanobacteria.

关 键 词：球状蓝细菌 微囊菌 微囊菌菌苗 微生物岩 谢家槽剖面 早三叠世 四川广安 

分 类 号：Q913.2[天文地球—古生物学与地层学]