摘要
湘西北地区露头区早奥陶世生物礁发育,主要造礁生物有蓝绿藻(包括 Cyanobacteria 和 Girvanella)、Pulchrilamina、Calathium、Batostoma、Archaeoscyphia。主要礁岩类型有障积岩和粘结岩,主要生物礁类型有障积礁和粘结礁。根据生物礁生长发育特征可将其分为三个阶段:奠基阶段、生长阶段和灭亡阶段。部分生物礁生长阶段形成的岩石类型上下不同,成礁方式也不同,据此可将生长阶段分为两期。根据生物礁上覆岩石类型的不同可推测其死亡方式是属淹死型还是属渴死型;根据围岩和礁岩的接触关系的不同,可形成追赶型和并进型两种生物礁埋藏模式。相对海平面的变化控制着生物礁的生长、发育、死亡和埋藏,海平面的上升和下降可形成生物礁不同的发育、死亡和埋藏模式组合。
The Early Ordovician bioherm develops at outcrops in the northwest part of Hunan.Reef-building organism mainly con- sists of Blue-green algae (including Cyanobacteria and Girva- nella),Pulchrilamina,Calathi,Batostoma,Archaeoscyphia. Bafflestone and boundstone are the main types of reef lime- stone so baffle and binding reefs are the main in reefs.Based on the features of growth and development,the stages of foun- dation,growth and death can be divided.Some reefs formed different types of reef rocks in the upper and lower parts in their reef bodies during different growth stages,which resulted in different reef-forming models,so that the growth stage can be subdivided into two phrases.According to the different fea- tures of overlying rock,the reef death model can be deduced to be drawn or thirsty.According to the different contact of reef rock with surrounding rock,the burial model can be de- duced to be catched-up or kept-up.Reef growth,develop- ment,death and burial were controlled by change of relative sea level,Ascending and descending sea levels resulted in different combined development-death-burial models of reefs.
出处
《海相油气地质》
2003年第1期30-34,共5页
Marine Origin Petroleum Geology
基金
国家自然科学基金成果(项目编号:49372116)
关键词
湘西北地区
早奥陶世
生物礁
成礁模式
Early Ordovician
Bioherm
Reef type
Reef-form-ing model
Northwest Hunan
