Organic reefs are favourabte accumulation spaces for hydrocarbons and various mineral resources. A complete Permian organic reef profile about 44 m thick with distribution area no more than 1 km2 is exposed near Lengw...Organic reefs are favourabte accumulation spaces for hydrocarbons and various mineral resources. A complete Permian organic reef profile about 44 m thick with distribution area no more than 1 km2 is exposed near Lengwu, Tongtu, Zhejiang Province. Examination of outcrops and thin sections revealed that the main reef-building organisms are catcisponges, with inozoans as dominant type. Five types of rocks have been recognized in the reef, and they are catcisponge framestone, catcisponge bafflestone, bindstone, rudstone and bioctastic wackestone. The profile was constructed in three reef-building stages. The thickness of the second stage is largest, followed by the first stage and the third stage is smallest. Each stage started with a frame-stone or bafflestone, ended as the reef grew near the sea-level, and died because of influx of terrigenous sediments. The development of the Lengwu reef is controlled by biological factors and sea-level changes. Based on the study a reef sedimentary model is established.展开更多
A calcisponge fauna occurs in uppermost Permian Conodont Clarkina meishanensis yini zone of the sequence exposed in the vicinity of Laibin, Guangxi Zhuang Autonomous Region, southern China. The fauna is dominated by o...A calcisponge fauna occurs in uppermost Permian Conodont Clarkina meishanensis yini zone of the sequence exposed in the vicinity of Laibin, Guangxi Zhuang Autonomous Region, southern China. The fauna is dominated by one thalamid species, Arnblysiphonella vesiculosa de Koninck, 1863, and one new scterosponge genus and species, Radiofibrosclera laibinensis gen. et sp. nov. They are associated with a few other accessory species, including the thalamid sponges Amblysiphonella laibinensis Deng, 1981, Colospongia sp., Polvcystocoelia sp., and the inozoan sponge Acoelia discontinua sp. nov. Though the individuals are abundant, the species diversity is very low. Without common calcisponge components of Changhsingian reefal faunas, the assembtage is interpreted as not a reefal fauna. The water depth at which they dwelled was less than 105 m, and more probably tess than 40 m. Its occurrence indicates a significant sea-level drop at the end of Late Permian Changhsingian Age.展开更多
文摘Organic reefs are favourabte accumulation spaces for hydrocarbons and various mineral resources. A complete Permian organic reef profile about 44 m thick with distribution area no more than 1 km2 is exposed near Lengwu, Tongtu, Zhejiang Province. Examination of outcrops and thin sections revealed that the main reef-building organisms are catcisponges, with inozoans as dominant type. Five types of rocks have been recognized in the reef, and they are catcisponge framestone, catcisponge bafflestone, bindstone, rudstone and bioctastic wackestone. The profile was constructed in three reef-building stages. The thickness of the second stage is largest, followed by the first stage and the third stage is smallest. Each stage started with a frame-stone or bafflestone, ended as the reef grew near the sea-level, and died because of influx of terrigenous sediments. The development of the Lengwu reef is controlled by biological factors and sea-level changes. Based on the study a reef sedimentary model is established.
基金supported by the National Natural Scientific Foundation of China(No.40172007,40472015,40802001,and 41372121)the key project from Chinese Academy of Sciences(No.KZ951B1-409)
文摘A calcisponge fauna occurs in uppermost Permian Conodont Clarkina meishanensis yini zone of the sequence exposed in the vicinity of Laibin, Guangxi Zhuang Autonomous Region, southern China. The fauna is dominated by one thalamid species, Arnblysiphonella vesiculosa de Koninck, 1863, and one new scterosponge genus and species, Radiofibrosclera laibinensis gen. et sp. nov. They are associated with a few other accessory species, including the thalamid sponges Amblysiphonella laibinensis Deng, 1981, Colospongia sp., Polvcystocoelia sp., and the inozoan sponge Acoelia discontinua sp. nov. Though the individuals are abundant, the species diversity is very low. Without common calcisponge components of Changhsingian reefal faunas, the assembtage is interpreted as not a reefal fauna. The water depth at which they dwelled was less than 105 m, and more probably tess than 40 m. Its occurrence indicates a significant sea-level drop at the end of Late Permian Changhsingian Age.
