甘(肃)新(疆)交界地区的石炭系和二叠系——兼论金窝子金矿围岩地层的时代

通过对甘新交界地区 3条石炭系和二叠系代表剖面的观察 ,结合多年调查东疆地层的资料积累 ,认为 :1)因绿条山组岩性组合及所含生物群与东疆的东古鲁巴斯套组相同 ,甘新交界地区绿条山组分布区是北塔山地层小区石炭系的南延部分 ,应从黑鹰山地层小区分出 ,甘新交界地区的中南部普遍缺失杜内期沉积 ;　 2 )阿齐山—康古尔—雅满苏火山岛弧带与博格达—哈尔里克火山岛弧带的构造造山历程不同 ,彼此的兴衰转换存在一定的时间差 ;　 3)甘肃北山石炭纪生物群与天山一级地层区的生物群相似 ,具有特提斯区系和西伯利亚—北美区系相互交会、混生的过渡性质 ;　 4 )来自兴蒙海槽的早二叠世海侵 ,未波及北疆地区 ,而是经由北山、红柳河谷地 ,终止于库姆塔格沙垄以东的狭小区域 ,根据雅满苏西大沟阿瑟尔期类化石的发现 ,推断至今从未发现早二叠世类化石的北山 ,主要原因是调查程度较低 ;　 5 )在金窝子金矿、2 10金矿及 2 30矿脉附近找到许多早二叠世生物化石 ,对仅根据一个同位素年龄数据 ( 36 1.1Ma)建立的“金窝子组”提出质疑 ,否定区内存在泥盆纪地层 ,认为金窝子金矿围岩地层的时代是早二叠世 ,不是晚泥盆世。

THE CARBONIFEROUS AND PERMIAN OF THE GANSU-XINJIANG BORDER AREA WITH REMARKS ON THE AGE OF THE SURROUNDING STRATA OF THE JINWOZI GOLD ORE

Through the observations on the three representative Carboniferous and Permian sections in the Gansu Xinjiang border area and combined with the data accumulated during many years of stratigraphical survey in East Xinjiang, it is regarded that 1) Because the lithological association and biotas contained are similar to those from the Donggulubasitao Formation, and being an extending southern part of the Carboniferous strata in the Santanghu Stratigraphical Subprovince, the distribution area of the Lutiaoshan Formation in the Gansu Xinjiang border area should be separated from the Heiyingshan Stratigraphical Subprovince. The Tournaisian deposits are generally lacking in the central southern part of the Gansu Xinjiang border area. 2) The Aqishan Kongguer Yamansu volcanic arc belt is different from the Bogada Haenlike volcanic arc belt in the tecto orogenic processes and there is a lead time in their rise, decline and change. 3) The Carboniferous biotas of Beishan, Gansu are similar to those of the stratigraphical region of Tianshan, Xinjiang, having a transitional nature of mixed biotas between Tethyan and Siberia North America biogeographical realms. 4) The Early Permian marine transgression from the Mongolia Hingan Ocean did not affect the North area beyond Tianshan Mts. of Xinjiang, but came by way of Beishan and Hongliuhe valley and terminated in a small narrow area east of Kumutage sand ribbon. It is inferred from the discovery of the fusulinids of Asselian stage in Xidagou of Yamansu that the main reason why the Early Permian fusulinids have never been found up to now in Beishan is the insufficient investigations in the past. 5) Because many Early Permian fossils have been found near Jinwozi Gold Ore, No.210 gold ore and No.230 auriferous vein, the “Jinwozi Formation” established only based on one isotopic datum (361.1Ma) is thus questioned, the presence of the Devonian strata in this border area is denied and the surrounding strata of the Jinwozi Gold Ore is considered to be Early Permian and not Late Devonian in age.