新疆叶城南部“赛力亚克达坂群”及其时代的商榷
Discussion on Age of “Sailiyakedaban Group” in Southern Yecheng, South Xinjiang, NW China

新疆叶城南部西昆仑山区的赛力亚克达坂一带，发育于麻扎-康西瓦构造带内的一套含煤碎屑岩系被命名为“赛力亚克达坂群”，并被认为是早-中三叠世沉积的地层.作为西昆仑和喀喇昆仑两板块分界，也是欧亚板块与“古特提斯域”分界的麻扎-康西瓦构造带，该陆相含煤碎屑岩系的时代对于西昆仑地区的大地构造和古地理演化的研究有着十分重要的意义.该套地层从岩性上大体可分为3个部分：下部以砾岩为主，中部以含煤及煤线为特征，上部以含砾砂岩为主.其中部产有以苏铁类(25%)、真蕨类(20%)、银杏类(20%)和松柏类(15%)占优势的植物群，共17属20种的植物化石.该植物群与西昆仑山及塔里木盆地边缘的叶尔羌群植物群相似，为兼有北方ConiopterisPhoenicopsis和南方PtilophyllumConioptersis植物群特征的早-中侏罗世植物群.另外，在岩性和地层序列上，麻扎-康西瓦构造带内的含煤碎屑岩系可与叶尔羌群进行对比，也适合叶尔羌群的定义.因而，建议废弃“赛力亚克达坂群”这一岩石地层单位，而沿用叶尔羌群，其时代为早-中侏罗世.
In the Sailiyakedaban area (in West Kunlun Mountains), Yecheng, South Xinjiang, a series of coalbearing clastic strata, distributed in the MazhaKangxiwa tectonic belt, is named as the Sailiyakedaban Group and considered as the EarlyMiddle Triassic strata. The MazhaKangxiwa tectonic belt is considered as the boundaries between the West Kunlun and the Karakoram plates, as well as between the Eurasian plate and the PaleoTethys domain, so the dating of the coalbearing clastics in the MazhaKangxiwa tectonic belt is significant to the study on the tectonic and paleogeographic evolution in West Kunlun Mountains. Lithologically, the coalbearing clastic strata can be divided into three parts: the lower part consists mainly of conglomerates, the middle part is characterized by coals, and the upper part consists mainly of pebbly sandstones. Abundant plant fossils, of 17 genus and 20 species, were collected from the middle part of the strata. The flora is predominated by Cycadophytes (25%), ferns (20%), Ginkgopsida (20%), and Confiers (15%). Similar to the Yarkant Group flora found in the West Kunlun Mountains and the margin of the Tarim basin, it shows the characteristics of both ConiopterisPhoenicopsis flora in North China and PtilophyllumConioptersis flora in South China during the EarlyMiddle Jurassic transition. In addition, the coalbearing clastic deposit in the MazhaKangxiwa tectonic belt not only is correlated with the Yarkant Group in the stratigraphic sequences and lithostratigraphy, but also conforms to the definition of the Yarkant Group. Therefore, the stratigraphic unit “Sailiyakedaban Group” of the EarlyMiddle Triassic is proposed to be suspended for use and to be replaced by the Yarkant Group of the EarlyMiddle Jurassic