Microbial controls on Panthalassan Carboniferous-Permian oceanic Buildups, Japan
Microbial controls on Panthalassan Carboniferous-Permian oceanic Buildups, Japan
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DOI：
10.1007/bf02546167
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发表时间：
1996-12
期刊：
影响因子：
1.8
通讯作者：
H. Sano;K. Kanmera
中科院分区：
文献类型：
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作者：
H. Sano;K. Kanmera
这一贡献强调了微生物外壳生物的重要造岩作用，包括结核菌，丝状蓝藻（主要是girvanellaand ortonella），以及在Panthalassa海洋中形成的石炭纪至二叠纪海底山脉上形成的古岩石。描述集中在这些微生物的古生物学特征和微生物结合岩和相关的隐微生物织物的岩石学性质。简要讨论了石炭纪-二叠纪泛海堆和泛古礁中主要造岩生物群的比较。研究了日本西南部下石炭统(Visean) -上二叠统（Murgabian）灰岩单元和下二叠统(Artinskian) -上二叠统（Murgabian）灰岩单元。所有这些石灰岩单元都被海洋岛屿型玄武岩所覆盖，完全不含陆源物质。这些石灰石位于日本破碎的增生地形中，被认为是海洋堆积在Panthalassan公海海域海底山上的遗迹。薄切片研究表明，丝状蓝藻、管藻和古石藻的沉积物结合和稳定作用对几种微生物结合岩和相关隐微生物织物的形成起着重要作用。无柄有孔虫、葛氏菌和相关的丝状蓝藻形成了束缚石和隐微生物的泥晶层/垫，其中捕获了骨骼碎片和球粒颗粒。fortonellland和相关丝状蓝藻的微小灌木既可以作为沉积物的阻挡物，也可以作为沉积物的粘合剂。管状结合石是由低层状致密的原位生长形成的。暗箱菌，常被丝状蓝藻菌包覆。合成复杂体，完全被古石器砾岩包覆，并被同沉积碳酸盐胶结物胶结。这些微生物结合岩和相关的隐微生物组构几乎存在于所有地层中，特别是在上石炭统和二叠统碳酸盐岩剖面中。相比之下，边界石的特点是大尺寸，抗波框架，由红珊瑚，毛纲和苔藓虫建造，只出现在横向离散的斑块中，在上维西河到下莫斯科河的间隔中占主导地位。在石炭纪到二叠纪期间，微生物岩和丝状蓝藻相关的隐微生物织物虽然不那么显眼，体积也小得多，但在Panthalassan海洋构造中占主导地位，而当时大多数大型框架构建者在全球范围内都处于贫困状态。在研究的泛海堆中，维桑到莫斯科早期丰富的珊瑚-苔藓虫组合对讨论泥盆纪末期危机后珊瑚礁生态系统的恢复具有特别重要的意义。Panthalassan礁群不同于它们与时间相当的泛古宙礁群，它们有能力建造抗波礁群。这些抗波的珊瑚-毛毛虫-苔藓虫礁被后莫斯科时期的微生物碳酸盐所取代，这是上石炭世和二叠纪秋吉和米诺地区碳酸盐堆积的特征。提出了对“Akoyoshi礁模型”的修正。
This contribution emphasizes the significant rock-building role of microbial encrusting organisms includingTubiphytes, filamentous cyanobacteria (mainlyGirvanellaandOrtonella), andArchaeolithoporellain the Carboniferous to Permian buildups that formed on seamounts in the Panthalassa ocean. The description concentrates on the paleontological characters of these microbes and the petrographic properties of the microbial bindstones and related cryptomicrobial fabrics. Comparisons of major rock-building biotas in the Carboniferous-Permian Panthalassan buildups and Pangean reefs are briefly discussed.The Lower Carboniferous (Visean) to upper Middle Permian (Murgabian) limestone units and the upper Lower to upper Middle Permian (Artinskian to Murgabian) limestone units in southwest Japan were examined. All these limestone units are underlain by oceanic island-type basalts and are totally free from terrigenous materials. The limestones are lying in disrupted accretionary terranes of Japan and are regarded as relicts of oceanic buildups upon seamounts in the Panthalassan open-ocean realm.Thin-section studies revealed that the sediment-binding and stabilizing of filamentous cyanobacteria,Tubiphytes, andArchaeolithoporellacontributed significantly to the formation of several varieties of microbial bindstone and related cryptomicrobial fabrics. Sessile foraminifers,Girvanellaand related filamentous cyanobacteria formed bindstones and cryptomicrobial micritic laminae/mats in which skeletal debris and peloidal grains have been trapped. Minute shrubs ofOrtonellaand related filamentous cyanobacteria acted as small-scale sediment-bafflers as well as sediment-binders.Tubiphytesbindstone was formed by the low-laminar and dense insitu growth ofT. obscurus, often encrusted by filamentous cyanobacteria.T. sosioensisformed complicated bodies that are completely encrusted byArchaeolithoporellaand cemented by syndepositional carbonate cement.These microbial bindstones and related cryptomicrobial fabrics are present in almost all the stratigraphic levels, especially in Upper Carboniferous and Permian carbonate sections. In contrast, boundstones, characterized by large-sized, wave-resistant frameworks and built by rugose corals, chaetetids, and bryozoans, only occurring in laterally discrete patches, dominate in an interval ranging from the Upper Visean to the Lower Moscovian. The microbialites and filamentous cyanobacteria-related cryptomicrobial fabrics, though less conspicuous and much smaller-sized, dominanted on the Panthalassan oceanic buildups during Carboniferous to Permian time when most large-sized frame-builders were globally impoverished.The Visean to early Moscovian abundance of the coralchaetetid-bryozoan association in the examined Panthalassan buildups is of special importance for the discussion on the recovery of the reef ecosystem after the end-Devonian crisis. The Panthalassan buildups differ from their time-equivalent Pangean reefs in the ability to construct wave-resistant reefs. These wave-resistant coral-chaetetid-bryozoan reefs were replaced by the post-Moscovian microbial carbonates, which characterize the Upper Carboniferous and Permian development of the carbonate buildups of the Akiyoshi and Mino teranes. A modification of the ‘Akoyoshi reef model’ is proposed.