新疆库鲁克塔格地区中奥陶统黑土凹组的放射虫新属种

NEW RADIOLARIAN GENERA AND SPECIES OF HEITUAO FORMATION(ORDOVICIAN) IN THE KURUKTAG REGION,XINJIANG

新疆库鲁克塔格地区的奥陶系黑土凹组黑色硅质岩中发现丰富的放射虫动物群,以泡沫虫类球形放射虫最多,不具外刺和具外刺的Inaniguttidae科占优势,及一些分类位置待定的特殊放射虫族群。本文描述该动物群中4个新属Quasibeothuka,Batoballa,Protosegmentum和Tetrasphaera,10个新种(Quasibeothuka fusiforma,Q.ovata,Q.ellipsoidala,Q.longifusiforma,Q.bithornya,Batoballa communis,B.longiovata,Protosegmentum xinjiangensis,Tetrasphaera kuruktagensis,Beothuka longispiniforma)。黑土凹组的放射虫动物群拟建立Tetras-phaerakuruktagensis带,下分二个亚带,下部的Protosegmentum xinjiangensis亚带和上部的Quasibeothuka fusi-forma亚带。该组的黑色页岩中产Exigraptus clavus带笔石化石,时代为中奥陶世大坪期。该组很可能是一个很好的生油层。

A rich radiolarian fauna is discovered in the Tetrasphaera kuruktagensis, Beothuka longispin- iforma） are described . Associated with the fauna includes graptolites of the Exigraptus clavus Biozone, which were found from the black shale of this formation, indicating Dapingian age （Middle Ordovician）. Based on the radiolarian fauna, Tetrasphaera kuruktagensis Biozone is identified, which includes two subzones, a lower Protoseg- mentum xinjiangensis Subzone and an upper Quasibeothuka fusiforma Subzone. This formation may be considered as a potential hydrocarbon source rock.