黑龙江省前寒武纪变质地层划分对比研究进展

    Research progress of the division and correlation of the Precambrian metamorphic strata in Heilongjiang Province

    • 摘要: 黑龙江省前寒武纪地层分布广泛,出露零星。通过对黑龙江省前寒武纪地层年代学、沉积建造、发育矿床特征及地层对比的综合分析显示,黑龙江省前寒武纪变质岩系和古生界锆石测年数据中出现有较多的太古宙、古元古代的谐和年龄,在古生代火成岩中也存在太古宙和古元古代捕获锆石的年龄数据信息,且黑龙江省前寒武纪变质基底主要为中-新元古界,产出沉积变质型铁矿和中、大型石墨矿床,发育典型的硅铁建造、孔兹岩系或含石墨岩系,并可在区域上对比。结合黑龙江省近年1:25万区域地质调查和相关科学研究成果,在额尔古纳地块上划分出古元古代表壳岩,将《黑龙江省区域地质志》置于新太古代的麻山群,置于古元古代的兴东群、东风山群、兴华渡口群修订为岩群,并依据近年来的区域地质调查成果、高精度测年资料、典型建造类型与变质程度等,将时代厘定为中-新元古代,同时依据建造和产出铁矿特征在宁安西南部地区划分对比出塔东岩群,为黑龙江省前寒武纪地质研究提供了地层学方面的资料。

       

      Abstract: Precambrian strata in Heilongjiang province are widely distributed with sporadic surface outcrops. Based on the comprehensive analysis of the Precambrian stratigraphic chronology, sedimentary formation and ore deposits hosted in the strata, the division and correlation results of the Precambrian metamorphic strata in this area are summarized. Zircon dating of Precambrian metamorphic rocks and Paleozoic strata in this area yield more Archean and Paleoproterozoic harmonic ages, and that of Paleozoic igneous rocks gives Archean and Paleoproterozoic harmonic ages. In addition, the Precambrian metamorphic basement in Heilongjiang Province is mainly the Meso-Neoproterozoic strata, and typical ferrosilicon formation, khondalite series or graphitic series that can be compared regionally are well developed in the sedimentary metamorphic iron deposits and the medium-large graphite deposits hosted in the strata. Based on the 1:250000 regional geological survey and related scientific research results in recent years, the Paleproterozoic surfaee rocks are demarcated in the Ergun Block. The late Archean Mashan Group, Paleoproterozoic Xingdong Group, Dongfeng Mountain Group and Xinghuadukou Group determined in "the regional geology of Heilongjiang province" are revised as rock groups. According to the regional geological survey, high-precision dating, typical formation types and metamorphic degree, the age is determined as Meso-Neoproterozoic. Meanwhile, based on the formation and characteristics of iron deposits, the Tadong Group is divided in the Ning'an area, which provides stratigraphic data for the study of Precambrian geology in Heilongjiang Province.

       

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