Review of geology, alteration and origin of iron oxide¨Capatite deposits in the Cretaceous Ningwu basin, Lower Yangtze River Valley, eastern China: Implications for ore genesis and geodynamic setting

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• 作者：Jinjie  ; Yu^a ;   ; ^{yjjchina@sina.com} ; Yuchuan  ; Chen^a ; Jingwen  ; Mao^a ; Franco  ; Pirajno^b ; Chao  ; Duan^a
• 关键词：Iron oxide&ndash ; apatite deposits ; Wall rock alteration ; Cretaceous Ningwu basin ; Eastern China ; Kiruna-type mineral system
• 刊名：Ore Geology Reviews
• 出版年：2011
• 出版时间：December 2011
• 年：2011
• 卷：43
• 期：1
• 页码：170-181
• 全文大小：3337 K

文摘

In the Cretaceous Ningwu volcano-sedimentary basin in the Yangtze River Valley metallogenic belt, eastern China, there are three areas with a dense distribution of magnetite or hematite deposits: the Meishan deposit in the north; Washan, Nanshan and Taocun deposits in the center; and the Zhongjiu and Gushan deposits in the south. The mineralization in the Ningwu basin is associated mainly with subvolcanic intrusions, consisting of gabbro¨Cdiorite porphyry and/or gabbro¨Cdiorite. Alteration zoning of these deposits is pronounced, and includes: (1) an upper light colored zone of argillic, kaolinite, silica, carbonate and pyritic alteration (2) a middle dark colored zone of diopside, fluorapatite¨Cmagnetite, phlogopite, and garnet with fluorapatite¨Cmagnetite; (3) a lower light colored zone of extensive albitic alteration. However, at the Gushan iron deposit, the lower light colored zone and the middle dark colored zone are absent, whereas the principal alteration is represented by silicification, kaolinization, and carbonatization.

The iron oxide¨Capatite deposits in the Ningwu basin are typically magmatic¨Cmetasomatic origin and are similar to the Kiruna-type deposits in Scandinavia, particularly with respect to mineral assemblages, fabric and structure of the iron ores, occurrence of the orebodies and wall rock alteration. The iron oxide¨Capatite deposits of the Ningwu basin contain magnetite and/or hematite, with diopside or actinolite and apatite gangue. They were formed in a rift or extensional environment and the mineralization is associated with alkaline magmatism. The time interval between magmatism and related mineralization is very short.