Geologogical Characteristics And Ore Genesis Of The Xishimen Iron Deposit

Xishimen iron ore located in the southern section of the Taihang Mountains, is one of rock type iron ore concentration area the largest skarn, large and small deposits have been found in more than 100. Due to various factors, more complex form of ore, ore formation age is mainly Yanshan period, the main ore body Fu presence of acid intrusive rocks in contact with carbonate rocks of the belt, ore types in this area is relatively simple, mainly magnetite. Through detailed field investigation and laboratory research, including magmatic petrology, geochemistry trace REE characteristics of rock, rock formation and study the causes of age, established Xishimen iron ore mineralization model.1. By zircon LA-ICP-MS-situ U-Pb dating of district technology, Wuan in amphibolite rock syenite were dating, get crystallization age of 135.6 ± 1.5Ma, indicating Wu’an complexes of formation time of Yansha n, petrology and geochemical characteristics of complex rock show that:(1) miscellaneous rock rock types are mainly hornblende diorite, diorite twelve diorite and hornblende syenite and flash long porphyry, diorite zone structures are developed plagioclase;(2)geochemistry of Wu’an complexes are shown in the presence of the main magmatic evolution of olivine, clinopyroxene, titanium oxide and phosphorus limestone and other minerals crystallization differentiation, and plagioclase crystallization differentiation obvious. However, this is difficult to explain the role of fractional crystallization Wu’an complexes with high Mg #, Cr isotopic composition and characteristics like EMI. So, Wu’an complexes magma in the process of evolution is bound to have a mantle to join, it may be in the process of magma rising magma source can also be.2. Alteration zonation points in space is regular, its features are:(1) alteration zone mainly developed in the contact zone of rock and carbonatite rock near the large-scale alteration, especially vertical the direction of the rock deep extending fo r hundreds of meters since the roof rock; generally have a clear line between(2), each with the product;(3) changes in mineral composition between different band with a mutation.3. Xishimen iron ore deposits of iron ore S isotopic composition studies show that small changes in the value of iron ore in the sulfide sulfur, sulfur composition described more stable. Δ34S magma mantle or general changes in 0 ~ 2 ‰, anhydrite δ34S = 24.0 ‰ ~ 29.1 ‰, while the typical heavy sulfur evaporation δ34S = 20 ‰ ~ 24 ‰. Thus, Handan- Xingtai area pyrite δ34S value skarn iron deposits between mantle sulfur and sulfur deposition, indicating that mineralization may be derived from magmatic fluids, and in the process of rising captured cream rock formations that ore- forming fluids δ34S value becomes larger. The district lead isotope model ages obvious differences may indicate that more and more types of mineralization and mineralization of times magma.4. Summary of previous research data and field research, analysis of the ore-controlling factors and metallogenic regularity Xishimen skarn iron ore region, pointed out the prospecting mark.