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据国外研究,有一定规模的风化淋滤型富铁矿床的形成和保存条件有四:1.有变质浅的、粒度细的火山-沉积型的厚大的贫矿层作矿源;2.炎热潮湿的古气候条件;3.适合的古构造、古地貌条件;4.富矿形成后,要很快被覆盖保存起来。冀东地区上述矿源层、古地貌等条件是具备的,但能否形成风化淋滤型富铁矿床的关键,首先就在于古气候条件是否有利。不同的古气候决定了不同的风化淋滤作用,从而产生不同的表生矿物类型和矿物的共生组合。本文则利用成因矿物学的方法来研究冀东长凝风化壳的类型,进而推断形成风化壳的古气候条件。
According to foreign studies, there is a certain scale of formation and preservation of weathered leaching iron-rich ore deposits in four areas: 1. There are volcanic-sedimentary thick lean ore bodies with shallow metamorphism and fine grain size as ore sources; 2. hot Humid paleoclimatic conditions; 3 suitable ancient structure, paleogeomorphology; 4, after the formation of rich ore, it should be quickly covered and preserved. Jidong area above the source rock, paleogeomorphology and other conditions are available, but the key to the formation of weathering and leaching of iron-rich deposits, the first is that the paleoclimatic conditions are favorable. Different paleoclimate determines the different leaching of weathering and leaching, resulting in different epigenetic mineral assemblages and minerals. In this paper, we use the method of genetic mineralogy to study the type of the Jidong long-setting weathering crust, and then infer the paleoclimatic conditions of weathering crust.