摘要
江西省杨桥矿区晚二叠世龙潭组含煤地层是一套海陆交互相沉积,沉积厚度在403m至437m,砂岩厚度占总厚度的五分之一。区内最常见的是含长石含岩屑石英砂岩,其次是含长石岩屑质石英砂岩、纯石英砂岩、长石质石英砂岩,杂砂岩很少。砂岩粒度以细砂级及微砂级为主,分选较好(Ⅰ级),矿物成熟度为准成熟(Ⅲ级)及成熟(Ⅱ级)。岩石中轻矿物以石英为主,次为燧石岩屑和长石,长石强烈水云母化。重矿物种类较多,但以较稳定的锆石和电气石为主,代表湿热气候条件下既有物理风化又有化学风化,碎屑物质经长距离搬运至滨海地区堆积的产物。狮子山段砂岩中锆石具有无色浑圆状,成分纯,分选和圆度较好,推测是再沉积成因的。官山段砂岩中含肉红色锆石,糙面显著,浑圆度好,具有古老的花岗-片麻岩建造的锆石特征,因此官山段砂岩的母岩可能是浙中南及闽北的古老的花岗岩和片麻岩。
The coal-bearing Longtan Formation of Late Permian in Yangqiao mine area in Jiangxi province is composed of alternating marine-terrestrial deposits.The total thickness ranges from 403鈥?37m, and one fifth of the total thickness is sandstone. The most commonly found sandstone is quartz-arenite with feldspar and rock fragments,the next,are lithic quartz-arenite with feldspar, quartz-arenite and feldspathic quartz-arenite, and the wackes are seldomly found. The sandstone strata are composed of fine to very fine grains of sands, well sorted (grade I), and is sub-mature (grade III) to mature (grade II) in mineralogy. The major light mineral in rock is quartz and the minor ones are chert fragments and feldspar. The feldspars in rocks have been strongly illitized. The heavy minerals in sandstone are varied. being mostly zircon and tourmaline,which indicated that the clastic materials were resulted from physical desintegration and chemical decomposition under tropical climate conditions, and then were transported for long distance to littoral areas and finally deposited there.Zircon in sandstone of Shizishan member is colorless, pure in composition, well rounded and sorted, showing that it is of re-deposition origin. Ziron grains in sandstone of Guanshan member are flesh-red in color and have evidently rough surfaces and are well rounded, which are similar to characteristics of old granite- gneiss formation, and therefore, suggest that the parent rocks of the Guanshan member are possibly the old granites and gneisses in the central and southern Zhejiang province and northern Fujian province.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
1989年第1期66-75,共10页
Journal of China Coal Society
