关于辽东－吉南中侏罗－早白垩世地层问题

ON THE PROBLEM ABOUT MIDDLE JURASS IC EARLY CRETACEOUS STRATA FROM EAST LIAONING TO SOUTH JILIN

吉南候家屯组与辽东小东沟组在辽东北部连成一体，以往地层划分和对比上的分歧，皆由王钰等定义小东沟组含有熔岩——“为小岭期火山喷发初的火山活动产物”所致。小东沟组、候家屯组为独立于辽东小岭组，吉南果松组火山岩之外的地层体，为干旱炎热气候条件下的河湖相沉积。辽东梨树沟组建立时未明确定义，建组剖面仅共分二层，为凝灰岩、凝灰质砂岩夹砂页岩，多数研究者将其理解为小岭期火山喷发的尾声产物，无疑是正确的，但近年已人为地演义为“远火山相和湖相”（沉积），并与辽西九佛堂（沙海）组对比，已失去岩石地层单位组的客观性、物质性及组内岩性、岩相的一致性。现据“组应概分，不易细分”等有关原则，建议废弃梨树沟组名称，将与小岭组有成因联系的远火山相产物（包括夹层）划归小岭组。

Houjiatun Formation(F.) in S.Jilin and Xiaodonggou F.in E.Liaoning are jointed together in the north part of E.Liaoning.Before differences of opinion on their subdivision and correlation all resulted from the definition made by Wang Yu et al .,which there is lava in Xiaodonggou F.They considered that the two Fs. were the products of volcanic activities in the early stage of volcanic eruption during Xiaoling age.The author holds that Xiaodonggou and Houjiatun rocks of Xiaodonggou F.in E.Liaoning and Guoshong F.in S.Jilin and the first two Fs.are of river lake facies deposition under the condition of dry and hot cliote.When Lishugou F.in E.Liaoning which is consisted of tuff,sand tuff interbedding sandy shale,was established,its definition was not madeclear.The author regard it undoubtedly right that Lishugou F.waste last produit of volcanic eruption in Xiaoling age ,but recently the above mentioned consideration was evolved into that Lishugou F.in E.Liaoning was of distal volcanic and lake faciesdeposition and it could be correlated with Jiufutang(Shahai)F. in W.Liaoning.On the principle of establishing a formation,the author propose that the name of Lishugou F.should be discarded and distal volcanic products (including inteabeds)origionally relatded with Xiaoling F.should be incorporated into xiaoling F.and the river lake(marsh) facies deposition above it which was not related with the volcanic druption in Xiaoling age should be incorporated into Nieerku F.