新疆准噶尔盆地周边晚石炭世的珊瑚*

新疆北部准噶尔盆地周边石炭系广泛出露, 其中上石炭统发育海相火山—沉积序列, 包括西准噶尔地区的哈拉阿拉特组、阿腊德依克赛组, 东准噶尔地区的石钱滩组以及盆地南部的祁家沟组、奥尔吐组等。本文研究在上述各地层的灰岩层或夹层、碎屑岩中获得的四射珊瑚9属17种和床板珊瑚2属3种, 对石钱滩组中的3个新种进行了详细的系统古生物学描述。上述珊瑚化石的地质时代主要为巴什基尔期至莫斯科期。在珊瑚动物群的组成上, 哈拉阿拉特组中新发现Caninophyllum属分子, 结合盆地东、西部共同产出的床板珊瑚Cystodendropora 属分子, 说明整个准噶尔盆地周边的动物群面貌大致类似, 而西准噶尔地区的化石丰度、分异度显著低于盆地东部和东南部。综合前人资料, 目前在准噶尔盆地周边发现的珊瑚化石有约一半为地方性分子。本文认为研究区珊瑚化石的分布和组成特征与晚石炭世准噶尔洋走向封闭或半封闭的演化趋势密切相关。

Upper Carboniferous corals from the Junggar Basin, northern Xinjiang, NW China

The Carboniferous strata are widely exposed in the Junggar Basin in northern Xinjiang. The following parts of these upper Carboniferous strata, including the Halaalate and Aladeyikesai formations in the West Junggar region, the Shiqiantan Formation in the East Junggar region, and the Qijiagou and Aoertu formations in the southern part of the basin, consist of marine volcanic-sedimentary sequences. In this study, nine genera and seventeen species of rugose corals as well as two genera and three species of tabulate corals are recognized from the limestone beds or interbeds, and siliciclastic rocks in the above-mentioned strata. Three new species of dissepimented solitary rugose corals are described from the Shiqiantan Formation. The geological age of these corals ranges mainly from the Bashkirian to the Moscovian. The abundance and diversity of corals in the West Junggar region are significantly lower than those in the eastern and southeastern regions. With regard to the composition of the coral fauna, the species of Caninophyllum from the Halaalate Formation and the widespread distribution of the genus Cystodendropora suggest that the coral assemblages from various regions of the Junggar Basin are comparable. Furthermore, in conjunction with a compilation of the published data on the upper Carboniferous strata from the Junggar Basin, almost half of the known coral species are endemic elements. This study suggests that the distribution and composition of the coral fauna are closely tied to the formation of trapped Junggar Ocean during the late Carboniferous.