大兴安岭北部沿江林场依列克得组含煤地层的初步研究

Preliminary study on coal-bearing Yiliekede Formation in Yanjiang Tree Farm in north of Daxing'anling Mountains

在大兴安岭北部塔河县北沿江林场西发现一个产热河生物群的化石点,化石产于依列克得组中。依列克得组分布于大兴安岭北部,是一套以中基性火山岩为主,局部含煤、油页岩等沉积夹层的地层。该组一般整合覆于上库力组之上,与上覆大磨拐河组煤系地层整合接触。其沉积夹层多为湖相沉积,产热河生物群化石。在沿江林场附近胜利煤矿出露的本组沉积夹层中发现大量孢粉及植物大化石,还有少量鲟鱼类、昆虫、叶肢介化石。经初步分析,此孢粉组合接近于海拉尔盆地南屯组至大磨拐河组下段之间的孢粉组合,化石群总体相当于热河生物群的中、晚期组合。

A new Jehol biota fossil site is discovered in west of Yanjiang Tree Farm, north Tahe County in north of Daxing＇anling Mountains, The fossils are from Yiliekede Formation which distributes in the north of the Daxing＇ anling Mountains, consisting of mainly medium basic volcanic rock and locally coal bearing and oil shale sedimentary interbeds. The formation overlies the Upper Kuli Formation in common conformity and is connected in confornlity with the coal measure strata in overlying Damoguaihe Formation. The sedimentary interbeds are mostly lacustrine facies with fossils of ＂Jehol Biota＂ in it. Large amount of sporopollen fossils, plant macrofossils and a few acipenseriformes, insects, conchostracas are found in the fonnation＇s interbeds cropping out from Shengli Coal Mine near Yanjiang Tree Farm. Preliminary analysis shows that, this sporopollen assemblage is similar to the assemblage between Nantun Formation to Lower Damoguaihe Formation in Hailar Basin. The overall assemblage corresponds to the metaphase and late phase assemblage of Jehol Biota.