淮北地区矽卡岩型铁铜矿床控矿条件分析与成矿模式

淮北地区位于安徽省北部，是重要金属成矿区之一。地质构造单元归属华北陆块，其矽卡岩型矿床的控矿条件和成矿模式既与华北地区邯邢式接触交代型铁矿床相似而又有区别。邯邢式铁矿主要围岩地层为奥陶系，矿石成分简单，以磁铁矿为主。淮北地区部分矿床具有这一特征，而另一部分矿床的特征与此有较大差异：围岩地层为寒武系，矿石成分复杂，以铁铜矿为主，并含有金、钼等其它有益元素，岩体分叉侵入，多层成矿，矿体产于燕山中期石英二长闪长玢岩与寒武系中上统内接触带及正接触带，镁质矽卡岩较发育，含铜矽卡岩可见于外接触带。为了与邯邢式铁矿区别，称其为前常式铁铜矿。本区矽卡岩型矿床的赋矿层位为中上寒武统一下奥陶统。其中，寒武系铁矿比例43．39％、铜矿比例92．67％、金矿比例100％，奥陶系铁矿比例56．61％、铜矿比例7．33％。本文在介绍地质背景的基础上、较系统地分析了控矿条件和成矿模式，提出了岩浆侵入活动中心（或活动带）与寒武系接触带为重点找矿方向的观点，并明确指出远离侵入中心（带）的岩床，其成矿性差。文中还介绍了覆盖区识别岩浆侵入活动中心（或活动带）的方法。

Analysis on ore-controlling conditions and metallogenic model of skarn type Fe and Cu deposits in Huaibai area

Located in North Anhui province, Huaibei area is one of the important metal mimeralized districts. The geologic structural unit of the area belongs to North China continental block, in which the ore-controlling conditions and metallogenie model of skarn type deposits are similar to but a little different from those of Handan-Xingtai contact metasomatic type iron deposits. The wall rocks of Handan-Xingtai type iron deposits mostly are Ordovician strata, the composition of ores is simple, being dominated by magnetites. A part of deposits in Huaibei area have the same characteristics showing in Handan-Xingtai type deposits. But the other part of deposits in Huaibei area has quite different characteristics. The wall rocks of deposits are Cambrian strata, the ores have complicated composition, being dominated by iron and copper ores containing gold, molybdenum and other available elements. The igneous bodies are shown as bifurcating intrusions causing to from multi- layered mineralizations. The ore bodies are occurred in contacts and endocontacts between middle Yanshan quartz monzodiorite porphyries and middle and upper Cambrian, with developing of magnesium skarns and Cu-bearing skarns in exodontists. In order to distinguish from Handan-Xingtai type iron deposits, the deposits in Huaibei area are named as Qianchang type skarn iron-copper deposits. The ore-bearing horizons are upper Cambrianlow Ordovician, in which the Cambrian iron ores make up 43.39%, copper ores 92.67% and gold ore 100%; the Ordovician iron ores make up 56.61% and copper ores 7.33%. Basing on the study on geological background of skarn iron-copper deposits in Huaibei area, the paper systematically analyzed ore-controlling conditions and metallogenic model for the deposits in Huaibei area, proposed that the contacts between magma intrusion center （belt） and Cambrian strata may be considered as the major ore-prospecting targets and clearly pointed out poor mineralizations of sills located far away from intrusion center. In addition, the way to recognize magma intrusion center in the area with overlying strata was introduced. province