云南省晋宁县天井铁矿床地质特征与成因探讨

发布时间：2018-06-04 22:09

本文选题：天井铁矿 + 矿床成因　；参考：《昆明理工大学》2015年硕士论文

【摘要】：云南省晋宁县天井铁矿床位于云南“山”字型构造脊柱南端偏西与前弧相邻部位,北起东山南至新龙潭山,正处于康滇地轴铁矿带上,成矿条件优越。但由于对天井铁矿床成矿背景、成矿机制的研究主要是在六七十年代进行的,后人很少对其进行剖析。所以天井铁矿床的具体成因尚不清楚,迫切需要进行分析,以便用理论支持深部找矿和区域找矿。本文综合分析区域成矿背景,结合滇中铁矿床的研究,对天井铁矿床进行了详细解剖。通过矿床地质调查、矿体形态描述、矿石特征总结、区域矿床对比等方面的研究,查明了其矿体分布特征、矿区容矿构造、成矿物质来源和大致的成矿年代,分析了天井铁矿床的成矿特征及规律,探讨了天井铁矿床的成因。野外调查发现,矿区主要出露中元古代昆阳群的美党组、大龙口组地层,矿区构造主要呈北东向展布。矿床由两个主矿体及十多条次要矿体组成,矿体受地层、北东向断裂及其次生断裂控制。赋矿围岩为大龙口组的灰岩,成矿对围岩的选择性强,矿体赋存于断裂带中,严格受地层、主干构造及其次生构造的控制,矿体呈南西—北东向展布,倾向以南东为主。矿床分为赋存于大龙口组灰岩中的矿床和残坡积矿。灰岩中的矿床矿石以赤铁矿为主,次为褐铁矿,还有少量的纤铁矿、针铁矿、软锰矿。脉石矿物以方解石、石英及白云石为主,有少量的绢云母和粘土矿物。原生矿石为赤铁矿,之后风化脱水形成褐铁矿。残坡积矿石基本为赤铁矿、褐铁矿碎块和粉末,其品位和夹杂的粘土多少以及灰岩中的矿体的距离有关。通过对天井铁矿的区域地质、矿床地质特征等的分析,认为矿区灰岩中的矿床属于中—低温热液充填交代型铁矿床,风化剥蚀形成残坡积矿床。最后通过对比研究,发现滇中地区与天井铁矿床地质特征基本相同的一系列铁矿床,其矿床与天井铁矿属同一类型。最后依据分析总结的找矿标志与野外勘查工作,为天井矿区下一步找矿粗略的指明了三个预测区。
[Abstract]:The Tianjing iron deposit in Jinning County, Yunnan Province is located in the south end of Yunnan's "mountain" type structure and adjacent to the front arc. It rises from Dongshan to Xinlongtan Mountain in the north and is located in the Kangdian axis iron ore belt, with favorable metallogenic conditions. However, because of the metallogenic background of the Liangjing iron deposit, the metallogenic mechanism was mainly studied in the 1960s and 1970s. Therefore, the cause of formation of the ore deposit in the courtyard is not clear, and it is urgent to analyze it in order to support the deep prospecting and regional prospecting with theory. In this paper, a comprehensive analysis of the regional metallogenic background, combined with the study of iron ore deposits in central Yunnan, the detailed anatomy of the iron ore deposits in the courtyard is carried out. Through the study of geological survey of ore deposit, description of ore body morphology, summary of ore characteristics and comparison of regional ore deposits, the distribution characteristics of orebody, ore-bearing structure, source of ore-forming material and approximate metallogenic age are found out. The metallogenic characteristics and rules of the iron ore deposit in the courtyard are analyzed, and the genesis of the ore deposit in the courtyard iron deposit is discussed. The field investigation shows that the strata of the Meidang formation and the Dalong mouth formation are mainly exposed in the middle Proterozoic Kunyang Group, and the structure of the mining area is mainly distributed in the north to east direction. The ore deposit is composed of two main orebodies and more than ten minor orebodies, which are controlled by strata, NE trending faults and their secondary faults. The ore-bearing surrounding rock is limestone of Dalong mouth formation, and its ore-forming selectivity is strong. The orebody occurs in the fault zone and is strictly controlled by strata, main structure and its secondary structure. The deposit can be divided into deposit and residual slope deposit in limestone of Dalong Kou formation. Hematite is the main ore in limestone, followed by limonite, and a small amount of pyrolusite, goethite and pyrolusite. Gangue minerals are mainly calcite quartz and dolomite with a small amount of sericite and clay minerals. The primary ore is hematite and then weathered and dehydrated to form limonite. The residual slope product ore is basically hematite, limonite fragment and powder, its grade is related to the amount of clay and the distance of ore body in limestone. Based on the analysis of the regional geology and geological characteristics of the Liangjing iron deposit, it is considered that the deposit in limestone belongs to the intermediate-low temperature hydrothermal filling metasomatic iron deposit, and weathering denudation forms the residual slope deposit. Finally, a series of iron ore deposits with the same geological characteristics are found in the central Yunnan area, and the ore deposits belong to the same type as the patio iron ore deposits. Finally, based on the analysis and summary of the prospecting criteria and field exploration work, three prediction areas are roughly indicated for the next prospecting in the patio mine area.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.31

【引证文献】