摘要
江西修水二叠系—三叠系界线地层有一段特殊构造的地层,下部为灰色部分和红色部分组成的斑状构造,上部为灰色部分和黄色部分组成的树枝状构造。这种树枝状构造的岩石与前人报道自重庆老龙洞剖面的微生物岩非常相似。岩石薄片观察表明,树枝状构造的暗色部分为残留的灰泥岩;浅色部分为灰岩经过重结晶、白云石化—去白云石化作用改造而成。在暗色的残留灰岩里有保存很好的丰富的球状微生物化石。研究认为,岩石中暗色部分和浅色部分的原始组分是同时沉积的;是成岩作用控制了浅色部分的形成。这一成果应当对认识老龙洞剖面树枝状微生物岩的成因有借鉴作用。
This paper deals with the origin of dendroid-structured rocks in the Permian-Triassic boundary section in Xiushui, Jiangxi Province. The dendroid structure in Xiushui resembles that described as ＂ microbialite crest＂ from the P-T boundary section in Laolongdong, Chongqing by previous researchers, and is composed of dendroid light-colored part in dendroid dark-colored rock part. This study reveals that the dark areas are residual lime mudstone; while the light areas are derived from recrystallization, dolomitization-dedolomitization of original limestone. The dark residual lime mudstone contains abundant spherical microbial fossils. Diagenesis such as recrystallization, dolomitization-dedolomitization is the controlling factor in the formation of the dendroid structures in Xiushui.
出处
《地质论评》
CAS
CSCD
北大核心
2007年第3期323-328,I0002,共7页
Geological Review
基金
国家自然科学基金资助项目(编号40472015)
现代古生物学和地层学国家重点实验室开放课题基金资助项目(编号053102)的成果
