甘肃省的三叠系

根据地层区划分原则,将省内三叠系划分为海、陆2个地层区和6个地层小区,阐述了各地层区特征,对顶、底界及统界进行了合理划分并提出了一些新的划分意见,对个别地层时代,据新资料进行了修改、厘定;建立了地层系统和地层层序,统一了地层单位和名称,选出代表性剖面,系统论述了岩性、岩相、厚度、古生物组合、接触关系及合矿性等特征;首次将三叠纪划分为海、陆两大生物区系,南部海相区,早、中三叠世主要属特提斯型生物区系,混有少量北方及环太平洋区系分子,北部陆相区的三叠纪及南部的南祁连小区和西秦岭小区的晚三叠世主要属北方型植物区系,仅西秦岭小区属不典型的南方型植物区系,两区间为混合型植物区系;按海、陆相各世分别总结了各门类古生物组合特征及与国内、外进行了对比;按海、陆相三叠系分别与国内、外有关地层进行了概略对比;按世分别编制了岩相古地理略图,并探讨了各地层小区内岩相古地理及古气候特征;概述了三叠纪沉积矿产煤、石油及层控矿产汞、锑等13种矿产的分布、含矿岩系及储存层位等特征。

TRIASSIC SYSTEM IN GANSU

Based on the principle of stratigraphic area classification, Triassic System of Gansu maybe divided into sea area and land area, they were divided into six region(lesser or minor) further. Character of each stratigraphic region was discussed. Top boundary, bottom boundary &series boundary of Triassic System were reasonably divided, and some new idea of division was given. Based on the new information, some stratigraphic age was revised. Stratigraphic system and stratigraphic sequence were established. Stratigraphic unit and stratigraphic name were u-nified. Representative section was found out. Character of lithology and lithofacies, thickness, association of extinct animals and plants, contact relation and ore -bearing were systematically discussed . Triassic System of Gansu was divided into both sea biota &land biota for the first time. In south seafacies area, Early Triassic and Middle Triassic mainly belongs to Tethys type biota, and these are some of North type and Circumpacific ocean type . Within it Triassic System in North Range landfacies area and Later Triassic of South Qilian region and West Qinling region in South Range mainly belong to North type flora,only West Qinling region belongs to the intypicat South type flora. The area between the both area is mixture type flora. Character of association of extinct animal and plant were summarized in the item of each period of seafacies and landfacies ,and the character were summarily compare with that of home and abroad. Lithofacies -paleo-geographic map of each epoch were edited. Character of lithofacies -paleo-geographic and paleoclimate of each region were discussed. It was summarily discussed that distribution, Ore - bearing rock, Storage horizon of thirteen deposit including sedimentary coal, oil, stratum central mercury, antimony et. al of Triassic System in Gansu.