摘要:
南天山西端的乌帕塔尔坎群为一套灰色、深灰色细碎屑岩,夹火山岩、硅岩和碳酸盐岩,其中分布有一些超基性岩(块)。以往曾据灰岩夹层中的化石将其划归志留系-中泥盆统或前泥盆系。我们对乌帕塔尔坎群中所采集的24块硅岩样品进行室内分离和鉴定,发现的放射虫化石主要有Albaillella sp. cf A. undulata Deflandre,Albaillella sp. cf A. paradoxa Deflandre,Albaillella cf. A. deflandrei Gourmelon,Albaillella sp. cf. A. indensis Won,Albaillella sp. cf. Albaillella excelsa Ishiga, Kitoand Imoto,Albaillella sp.和Latentifistulidae gen. et. sp. indet.。其中可划分出两个放射虫化石组合,一个是以Albaillella sp. cf A. undulata Deflandre,Albaillella sp.cf A. paradoxa Deflandre,Albaillella cf. A. deflandrei Gourmelon和Albaillella sp. cf. A. indensis Won为代表的早石炭世早期的化石组合;另一个是以Albaillella sp. cf. Albaillella excelsa Ishiga, Kito and Imoto为代表的晚二叠世化石组合。说明乌帕塔尔坎群至少可能包含有志留系到二叠系不同时代的岩石,可能是蛇绿混杂岩。这是该群首次发现放射虫化石,特别是再次发现晚二叠世放射虫化石,进一步证实了南天山西段晚二叠世(残余)古洋盆存在的可能性。
Abstract:
The Wupatarkan Group (or the Wupatarkan Formation), distributed at the west terminal of Chinese South Tianshan, consisted mainly of gray and dark gray fine-grained clastic rocks, interlayered with volcanic rocks, carbonate rocks and chert, with some ultra-basic rocks (blocks) in it. Generally, it was ascribed in ages of Silurian-Middle Devonian, Silurian-Early Devonian or pre-Devonian according to Atrypa bodini Mansuy, Hypothyridina parallelepipedia (Brour.) and Prismatophyllum hexagonum Yoh found from the limestone interlayers. 24 chert specimens were analyzed, from which the radiolarian fossils included Albaillella sp. cf A. undulata Deflandre, Albaillella sp. cf A. paradoxa Deflandre, Albaillella cf. A. deflandrei Gourmelon, Albaillella sp. cf. A. indensis Won, Albaillella sp. cf. Albaillella excelsa Ishiga, Kito and Imoto, Albaillella sp. and Latentifistulidae gen. et. sp. indet. Two radiolaria group could be recognized, one being early Early Carboniferous group represented with Albaillella sp. cf A. undulata Deflandre, Albaillella sp. cf A. paradoxa Deflandre, Albaillella cf. A. deflandrei Gourmelon and Albaillella sp. cf. A. indensis Won, another being Late Permian group represented with Albaillella sp. cf. Albaillella excelsa Ishiga, Kito and Imoto. This new discovery indicated that the Wupatarkan Group, consisted of rocks in varied ages from Silurian to Permian, was probably an ophiolitic mélange. These firstly discovered radiolarian fossils, especially the Late Permian Albaillella sp. cf. Albaillella excelsa, confirmed the understanding that the relic ancient oceanic basin occurred in west part of the Chinese South Tianshan during Late Permian.
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