Preliminary Study of Carbonate Mud-mounds, Middle-Late Ordovician,Tazhong Area
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摘要: 塔中地区中晚奥陶世灰泥丘是在古老碳酸盐岩台地逐渐沉没过程中生长发育的。横向上，它向台地高部位层层爬坡，纵向上，为多旋回叠丘。建造灰泥砂丘的生物主要是菌藻类—奥特藻及其相近的属，尚有珊瑚、苔藓虫、层孔虫、海绵等。其岩石类型主要是泥晶凝块格架岩、泥晶凝块障积格架岩、泥晶藻凝块粘结岩。其沉积相可分为丘中心、丘前和丘间三个相带。灰泥丘的演化受控于海进速率同灰泥丘的增长速率及海水深度与浊度。Abstract: Carbonate mud-mounds of Middle-Late Ordovician age in Tazhong area grew and developed on an old carbonate platform when it was progressively sinking b elow the sea level.Those laterally climbed up the slope toward high position of the platform,and vertically are the multiple superimposed mud-mound.The main mu d-mound-building organisms are bacterium and algae,such as ortonella and its k ind genus.The secondary organisms are Tabulati,Btyozoa,stromatoproids,spongea,an d so on .It is considered that the rock types of the mud-mounds are dominantly micrite-thromoblites framestone,micrite-thrombolites baffle-framestone,algal micrite-thrombolites bindstone. Mud-mound facies may be divided into three sub facies such as mud-mound centre,mud-mound talus and intermud mound-deposit. Th e evolution of mud-mound was controlled by the relationship between the rate of transgressive and the rate of mud-mounds growth,and by the change of water dep th and turbidity.
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Key words:
- carbonate /
- mud-mound /
- mud-mound-building /
- organisms /
- mud-mound
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[1] 俞剑华，边立曾.浙赣交界地区晚奥陶世生物礁初步研究[J] .南京大学学 报(地球科学版)，1992，4(2)：1～3 [2] 边立曾，方一亭，黄志诚.浙赣交界区晚奥陶世生物礁类型及其特征[A] .见:范 嘉松主编，中国生物礁与油气[C] .北京：海洋出版社.1996.54～75 [3] 张永辂，刘冠邦，边立曾等主编.古生物学[M] .北京：地质出版社,1988.350～ 400 [4] 郑荣才.湖南西部花垣县渔塘早寒武世藻礁[A] .见:范嘉松主编：中国生物礁 与油气[C] .北京：海洋出版社,1996.29～38 -
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