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Pelagic Manganese Nodules--A New Type of oncolites

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Acta Geologica Sinica(English Edition) 1997年第1期71卷 43-48,115-116页

作者： Bian Lizeng Lin Chengyi Zhang Fusheng Du De’an Chen Jianlin and Shen Huadi Department of Earth Sciences Centre for Materiale Analysis,Nanjing University,Jiangsu Second Institute of Oceanography, State Oceanic Administration,Hangzhou, Zhejiang Liu Xinzhu

Pelagic manganese nodules from the East Pacific Ocean have been studied using polarizing,scanning electron and transmission electron microscopes. It has been revealed that the manganesenodules are composed of cores and stromatolite coatings. The structures and textures of thesenodules are peculiar to oncolite. Consequently, the pelagic manganese nodules are manganeseoncolites. Based on the stromatolites in the coatings, the manganese oncolites from the East Paci-fic Ocean can be divided into two types. One is smooth on surface and dense inside. Its coatingsare composed mainly of Minima. The other has a knobby surface and is loose internally. Itscoatings consist mainly of Admirabilis. The TEM investigation has also revealed that the con-structors of the manganese oncolites are ultra-microbes. The Minima is constructed byMiniactinomyces chinensis sp. nov. and the Admirabilis is built by Spirisosphaerospora pacifica ***.

关键词： pelagic manganese nodule oncolite stromatolite ultra-microfossil

Petrography and origin of the Lower Ordovician microbial carbonates in the Songzi Area of Hubei Province,middle Yangtze region,China

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Petroleum Science 2019年第5期16卷 956-971页

作者： Chuan-Tao Xiao Guo-Qi Wei Zhen-Yu Song Yun-Peng Xiao Wei Yang Man Dong Yun-Fei Huang Da Gao Geosciences School of Yangtze University Wuhan 430100HubeiChina Research Institute of Petroleum Exploration and Development PetroChinaLangfang 065007HebeiChina

This study is the first systematic assessment of the Lower Ordovician microbial carbonates in Songzi,Hubei Province,*** paper divides the microbial carbonates into two types according to growth patterns,namely nongranular and *** nongranular types include stromatolites,thrombolites,dendrolites,leiolites and laminites;the granular types are mainly oncolites and may include a small amount of microbiogenic *** to their geometric features,the stromatolites can be divided into four types:stratiform,wavy,columnar and ***,dipyramidal columnar stromatolites are identified for the first time and represent a new type of columnar *** thrombolites are divided into three types:speckled,reticulated and *** grazing gastropod Ecculiomphalus and traces of bioturbation are observed in the speckled and reticulated *** paper considers these two kinds of thrombolites to represent bioturbated *** findings not only fill gaps in the field of domestic Ordovician bioturbated thrombolites but also provide new information for the study of *** on the analysis of the sedimentary characteristics of microbialites,the depositional environments of the various types of microbialites are described,and the distribution patterns of their depositional environments are *** relationship between the development of microbialites and the evolution and radiation of metazoans during the Early to Middle Ordovician is *** with the correspondence between the stepwise and rapid radiation of metazoans and the abrupt reduction in the number of microbialites between the late Early Ordovician and the early Middle Ordovician,fossils of benthonic grazing gastropods(Ecculiomphalus)were found in the stromatolites and thrombolite of the study *** is believed that the gradual reduction in microbialites was related to the rapid increase in the abundance of *** not only graze

关键词： Microbial carbonate Stromatolites Thrombolites oncolite Lower Ordovician Songzi Area

Distribution and depositional model of microbial carbonates in the Ordovician middle assemblage,Ordos Basin,NW China

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Petroleum Exploration and Development 2021年第6期48卷 1341-1353页

作者： WEI Liubin ZHAO Junxing SU Zhongtang WEI Xinshan REN Junfeng HUANG Zhengliang WU Chunying State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu 610059China Institute of Sedimentary Geology Chengdu University of TechnologyChengdu 610059China Exploration and Development Research Institute of PetroChina Changqing Oilfield Company Xi’an 710018China National Engineering Laboratory for Exploration and Development of Low-Permeability Oil&Gas Fields Xi’an 710018China

Based on outcrop profiles,drilling cores,cast thin sections etc.,the types,microfacies combinations and distribution pattern of microbial carbonates in the Ordovician middle assemblage of the mid-eastern Ordos Basin have been systematically *** middle assemblage of Ordovician in the mid-eastern Ordos Basin has microbial carbonates formed by the calci-fication of cyanobacteria,including microbial biostromes and microbial mounds made of stromatolites,thrombolites,and *** distribution of the carbonates shows obvious“stratum-control”and“regional”*** microbial bio-stromes 2–3 m thick each are controlled by sequence cycles and sedimentary facies changes,and were mainly formed in the tidal flat environment during the depositional stages of the Ma56 and Ma55 *** microbial biostrome in the Ma55 sub-member occurring near the carbonate-evaporite transition interface in the early stage of the transgression is distributed mainly in the Mizhi subsag in the eastern part of the basin;the microbial biostrome in the Ma56 sub-member turns up near the carbonate-evoporite transition zone in ring shape in the east of the central *** ancient landform had noticeable control on the distribution of microbial *** microbial mounds or mound-shoal complexes developing mainly during the de-positional stages of Ma57_Ma510 sub-members are about 15–25 m thick in single layer and distributed largely in the Wushenqi-Jingbian *** development model of the microbial carbonate rocks shows that the carbonate-evaporite lithologic transition zone and the Wushenqi-Jingbian paleouplift are favorable exploration zones of microbial carbonates in the Ordovician middle assemblages.

关键词： Ordos Basin Ordovician Majiagou Formation microbial carbonates stromatolite thrombolite oncolite deposi-tional model