西藏改则县玛米雪山北坡晚石炭世的腕足动物化石

本文报导了玛米雪山北坡的腕足动物化石。玛米雪山北坡含此化石的地层过去划归白垩系,腕足动物化石在此地的发现是第一次,它对于本区地层系统的建立及重建本区地质历史和古地理环境都有重要意义。 玛米雪山北坡腕足类化石、数量非常多,本文共描述了12个属15个种,其中新属1个,新种6个,它们是:Trichochonetes xizangensis sp.n.,Neo-chonetes gigantea sp. n.,Canorneilla semicircularis sp. n.,Ovatiamamixueshanensis sp. n.,Lissochonetes sp.,Marginifera sp.,Tib-etospirifer xizangensis gen.＆ sp. n.,T. mamixueshanensis sp.n.,Brachythyrina stranywaysi(Vern.),B.rectangula(Kut.),B.lataChao,Choristites cf. xianzaensis Yang,Neospirifer sp.,Punctos-pirifer sp.,Dielasma spp..并依据岩性和化石组合特征建立了一个新的地层单位—玛米雪山组,时代为晚石炭世。

UPPER CARBONIFEROUS BRACHIOPOD FOSSILS FROM NORTHERN SLOPE OF MAMIXUEHAN IN GAIZE COUNTY OF ALI REGION, XIZANG (TIBET) AUT REG

Brachiopod fossils reported and described in this paper were collected from northern slope of Mamixueshan (Mt.) in Gaize County of Ali Region, Xizang (Tibet) Aut. Reg..Brachiopod-bearing strata were referred to Cretaceous. The brachiopod fossils discovered for the first time in this area provided important and significant data to establish strata system and reconstruct the Geological History and Palaeogeographic environments.Abundant brachiopod fossils were collected in this area. 12 genera and 15 species are reported and described with 1 new genus and 6 new species; they are: Trichochonetes xizangensis sp. n.,Neochonetes gigantea sp., n., Cancrinella semicircularis sp. n, . Ovatia mamixueshanensis sp. n, . Lissochonetes sp, . Ma-rginifera sp., Tibetospirifer xizangensis gen. & sp. n., T. mamixueshanensis sp. n., Brachytliyrina strangwaysi (Vern.), B. rectangula (Kut.), B. lata Chao, Choristites of. xianzaensis Yang.Neospirifer sp., Punclospirifer sp., Dielasma spp..A new stratigraphic unit-Mamixueshan Formation is established, according to its lithologic character and brachiopod assemblage, to represent the fossil-bearing strata which is referred to Upper Carboniferous.