摘要
中国的白垩系除西藏、东喀喇昆仑、昆仑南缘、塔里木西缘、黑龙江东部及台湾等地区有海相及海陆交互相沉积之外,其余广大地域均为非海相沉积。按其沉积特征可分为两种类型:内陆盆地沉积型、火山及火山碎屑沉积型。内陆盆地沉积主要分布在大兴安岭及其以东至松花江两岸和陕甘宁盆地、新疆北部以及川滇等地区,岩性以暗色或红色夹杂色砂泥岩为主;火山和火山碎屑沉积主要分布在濒临太平洋的东部沿海地区及雅鲁藏布江两侧,岩性以火山碎屑沉积为主。非海相白垩系厚度巨大,层序齐全,其中含有极其丰富的陆生生物群,其赋存之多、分布之广、属种之繁盛程度是世界各大陆无可比拟的(表1),而且其中又蕴藏有丰富的矿产资源。
In China the Cretaceous marine facies and the interbedding of marine and continental facies are only developed in Xizang(Tibet),east Kala-Kunlun,southern piedmont of Kunlun,western part of Tarim Basin,eastern Heilungjiang and Taiwan province.In other vast areas of the country,terrestrial facies of Cretaceous containing abundant non-marine biotas widespreads in various inland basins.Evolution of life forms and development of sedimentation indicated by the vertical changes in fossil assemblages and lithological characteristics suggest a tripartite character of the non-marine Cretaceous and this is taken as the basis for dividing it into three series.The lower series is well represented by the Zhidan Group(equivalent to the Rehe Group of North China and the Jiande Group of southeast China),predominated by sandy and clayish beds,brownish red and brick-red in colour with mottled intercalations,coal-seams and pyroclastie rocks in most localities.Important elements of the lower series biotas comprise Charophyta:Mesochara stiptata(S.Wang)Z.Wang;higher plants:the Acanthopteris gothani Sze-Ruffordia goepperti(Dunker)flora and the Pilosisporites-Cicatricosisporites sporo-pollen assemblages;Bivalvia:Nakamuranaia chingshanensis(Grabau),Nippononaia tetoriensis Maeda,Sphaerium jeholense(Grabau),"Corbicula(Mesocorbicula)"tetoriensis Kobayashi et Suzuki;Ostracoda:Cypridea vitimensis Mandelstam,C.sulcata Mandelstam,C.koskulensis Mandelstam,C.kansuensis Hou,Limnocypredea subplana Lübimova;Conchastraca:the Eosestheria-Yanjiestheria assemblage;Insecta:Ephemeropsis trisetalis Eichwald;Pisces:the Ly-coptera-Sinamia fauna and Dinosauria:Psittacosaurus.The lower series is probably of Neocom age.The middle series is well represented by the Yongkang Group(equivalent to the lower part of the Songhuajiang Group and the Huashan Group of Northeast China),which is dominated by a suite of brick-red to red clastic deposits changing laterally into variegated lacustrine beds in some districts.Main fossil contents of the middle series include Charophyta:Atopochara trivalvia Peck;Bivalvia:the Trigonioides-Plicatounio-Nippononaia fauna;Ostracoda:the Cypridea(Morinia)-C.(Bisulcocypridea)-Ilyocyprimorpha-Ziziphocypris simakovi Mandelstam fauna,the geological age of the middle series is probably from Apt to Turon.The upper series is well represented by the Wangshi Group(equivalent to the upper part of the Songhuajiang Group of Northeast China and the Nanxiong Formation of Guangdong),lithologically similar to the middle series and the fossil biotas are characterized by the rapid increase in angiosperms among plants and sporo-pollen assemblage;by the flourish of Talicypridea(=Cristocypridea),the decline of Cypridea and the occurrence of some Cenozoic genera,such as Candona and Candoniella among ostracodes as well as by the thriving of pseudohyria among bivalves.Important vertebrate fossils are Hadrosourus,Tyranosaurus and abundant Oolithes.The main representative of charophytes is Latochara curtula Z.Wang.So the geological age of the upper series is probably from Coniac to Maastricht.According to the chronological age indicated by the fossil assemblages and to the radiometric determinations on the volcanies from the Rehe Group in North China and the Jiande Group in South China,the non-marine Juro-Cretaceous boundary should be put within the lowest part of the Rehe and the Jiande groups and their equivalents or at the base of these groups.The radiometric age of them is about 137—135 m.y.
作者
郝诒纯
苏德英
李友桂
余静贤
张望平
李佩贤
齐骅
关绍曾
郭福祥
Hao Yichun;Su Deying;Li Yougui;Yu Jingxian;Zhang Wangping;Li Peixian;Qi Hua;Guan Shaozeng;Guo Fuxiang
出处
《地质学报》
1982年第3期187-199,共13页
Acta Geologica Sinica
