新疆阿勒泰地区变质岩中微古植物群的发现及其地质意义

DISCOVERY AND GEOLOGICAL SIGNIFICANCE OF MICROPALEOFLORA FROM THE METAMORPHIC ROCKS IN ALTAY REGION OF XINJIANG

阿勒泰地区变质岩很发育,而且厚度巨大,属于地槽型浅海复理石沉积.由于变质岩地层缺少生物化石,地质学者对其划分及对比有不同的认识.笔者(1987)在阿勒泰地区研究地层古生物时,从黑山头—喀纳斯湖、锡伯渡—库鲁木提及北塔山—青河地区的29个剖面采集了216个微生物样品,其中15个剖面含震旦纪的微古植物群,1个剖面含晚奥陶世—早志留世的微古植物群,这些古植物的发现对查清这些变质岩岩层的时代及地层划分、对比将起重要的作用.

The Altay region is located in the frontier of the north part of Xinjiang,China, Where the metamorphic rocks are well developed with huge thickness and belong to shallowmarine flysch deposits of geosynclinal type.Owing to wanting in biological fossils, the subdivision and correlation of the metamorphic strata in this region are recognized by the Geologists with some disagreement. In 1987, we have studied the biostratigraphy in the Altay region, northern Xinjiang, and collected 216 samples of Micropaleoflora from 26 points in the Heishan-tou to Halas Lake and the Xibodu to Kulumuti and the Beitashan to Qinghe sections.We have found more abundant Micropaleoflora within 52 samples of 16 sections. Among them 15 sections contain Micropaleoflora Group of Sinian which are composed mainly of Leiominuscula minuta, Leiopsophosphaera densa, Trematosphaeri-dium, Trachysphaeridium, Turuchania, Micrhystridium minimum, Leiofusa naviculara Conusmorpha brevis, Triangumorpha, Quadramorpha, Anguloplanina rhombica, Polye-dryxium, Pulvinosphaeridium, Paleamorpha punctulata, Taeniatum crassum and Lami-narites, etc. There is 1 point of section contained Micropaleoflora Group of Upper Ordovician to Lower Silurien which are composed mainly of Triangumorpha, Veryha-chium, Micrhystridium, Tylotopalla, Goniosphaeridium , Trunculurarium, Ammonidium. Leiofusa, Eupoikilofusa, Deunffia and pirea, etc. The discovery of the above mentioned Micropaleoflora can play an important role for ascertain the ages of the metamorphic strata, as well as in dividing and correlating the motamorphic strata in this region.