534铀矿床地质特征及成矿条件探讨

A STUDY ON GEOLOGICAL CHARACTERISTICS AND METALLOGENETIC CONDITION OF URANIUM DEPOSIT NO.534

Uranium deposit No.534 occurs at the north margin of North China Platform, and is a volcanic hydrothermal deposit. The mineralization is characterized by obvious vertical zoning, the upper ore body is stratoid, stratiform and occurs as black disseminated UMo ore; the lower ore body is lenticular, irregular in form, composed of red, vein-like uranium ore. The wall rock alteration is intense, mainly appears as hydromicazation, fluoritization, silicification and hematitization. The ore-controlling conditions of the deposit are: (a) The Upper Jurassic acidic volcanic rock of Zhangjiakou Formation with higher uranium abundance is supposed to be the uranium source-bed; (b) Mineralization is closely related to subrhyolite-porphyry of the middle stage of Yanshan cycle; (c) Multiple hydrothermal activity favourable for mineralization; (d) The graben-horst system and microfissure zones developed in mining area are respectively localization of uranium deposit and ore-hosting structure. The major direction for uranium exploration is to look for steeplydipping and vein-like uranium mineralization at the contact zone of concealed subrhyolite-porphyry and new mineralized area along fault system between graben and horst.