Study On Geological Characteristics Of Iron Ore Deposits And Buried Ore Prospecting In Anshan Region

Anshan is one of the most important iron-producing base in China, where the proved iron ore reserves are about7.5billion ton in less than500km2. The reconnaissance of iron ore reached high degree after the systematic research of1950’s, and experiences the new ore-prospecting climax in the beginning of the21st century. Based on the detailed study of the regional geological characteristics of iron ore deposits, the thesis focuses on the regional metallogentic regularities and effective prospecting methods for buried ores. The significance of the thesis is, firstly aiming to new ore finding in the highly-researched area through further reconnaissance and enlarge the reserves and also provide basis for target-selecting and reconnaissance design, which is a big challenge and economic beneficial; secondly only new idea on fundamental geology can lead to the break-through of ore prospecting in such area as highly-researched, numerous concluding remarks coexisting. The paper aims to summarize the thoughts of iron ore prospecting in new situation by sum-up of the target-selecting reason and procedure of typical prospecting implement, and the main achievement is as following:1. Based on the systematic research of Archean geologic settings and regional metallogentic regularities of iron ores in Anshan region, the ore-forming terrain can be classified into six tectonic units, i.e., Tiejiashan granite terrain, Qidashan granite terrain, Tanggangzi granite terrain, sunken-margin of west Anshan city, SN iron tectonic belt and EW iron tectonic belt.2. The analysis on geologic evolution indicates that Anshan region is an ancient granite dome centered Tiejiashan, and the SN and EW iron belt came into being due to the intrusion of Qidashan and Tanggangzi granite bodies.3. The SN and EW iron belt were formed in late Archean era, and greatly influenced by the splitting, sinking and folding recurrent of Palaeo-Proterozoic Liaodong-Jinan ancient rifting and the sinking of later Taizihe depression; the EW iron belt was rebuilt by the Mesozoic Hanling fault zone, thus led to the formation of nowdays pattern of Anshan region.4. The phsical properties of ores and rocks of Anshan region are analyzed and the occurrence and distribution characteristics of magnetic anomaly are summerized. The result indicates that there are no other magnetic anomalies existing in Anshan region, and the magnetic method is the most useful method for iron ore hunting. The possible gravity interfaces are analyzed and the whether magnetic and gravity are spatially homologous is helpful to the ocurrence of deep iron ore bodies.5. The preservation conditions, especially the folds and faults which greatly influence the occurrence of iron ore bodies, comined with the quantitive computation of magnetic data, is the most useful method for buried iron ore propecting in exploited mining area.6. Based on the above-mentioned results, Heishilazi, Chentaigou and Beishanqiaonan iron deposit are selected for buried ore prospecting and nealy1billion tonnage iron ore reserve is obtained.