湖南桃源九溪地区下奥陶统石灰岩中新生变形残基的识别及其成因探讨  

RECOGNITION AND ORIGIN OF THE NEOMORPHIC RELICS IN THE LOWER ORDOVICIAN LIMESTONES,JIUXI AREA,TAOYUAN COUNTY,HUNAN PROVINCE,CHINA

作　　者：王正允[1] 郭建华[1] 王方平[1] 

机构地区：[1]江汉石油学院

出　　处：《南方油气地质》1995年第1期22-28,T001,共7页

摘　　要：在湖南桃源九溪地区下奥陶统石灰岩成岩作用的研究基础上,提出了新生变形残基的概念。这种残基具有与细砂-粉砂级内碎屑相类似的形态,根据:1)残基及其间的微亮晶带具有明显的新生变形特征;2)残基与微亮晶的化学成分相似,而与典型的胶结物区别明显;3)原分布于灰泥基质中的自生石英晶体或其假晶仍存在于残基和微亮晶带内,不出现于胶结物中;4)与残基共生的生物碎屑显示了弱水动力条件,残基是一种成岩产物。其成因主要是在早期成岩阶段,由于新生变形微亮晶的发育,逐渐分隔改造了原来基本均一的灰泥基质,其中未受影响或影响轻微的残余部分最终成为残基。微亮晶是沿着灰泥基质中的残余孔隙经过了成核、格架形成和溶液膜三个阶段逐渐发育的。正确识别残基并阐明其成因,在灰岩结构及分类研究、沉积环境分析、储集岩孔隙演化研究等方面均具重要意义。The concept of neomorphic relics is proposed herein, Based on the following features: (1) the relics and inter-relic microspar zones have distictly neomorphic characteristics; (2) the chemical composi- tion of relics is similar to the microspar, but obviously different from typical cement; (3) the crystals of au- thingenic quartz or their pseudomorphs, originally distributed within marl matrix, still exist in the relics and microspar zones, but not in the cement; (4) the paragenetic bioclasts with relics show as weak hydrody- namic conditions, etc., it is regarded that with appearances analogous to the intraclasts of silt-finesand grads, the neomorphic relics are a kind of diagenetic products. Due to the gowth of neomorphic microspar in the early diagenesis, the originally unified marl martrix would be gradually isolated and reformed, Along the residual pores within marl matrix, the neomorphic relics have gradually developed and undergoing, three evolutionary stages, named as uncleation, framework and solution film.

关 键 词：石灰岩 成岩作用 微观结构 早奥陶世 成因 

分 类 号：P588.245[天文地球—岩石学]