A comparison study of tungsten-bearing granite and related mineralization in the northern Jiangxi-southern Anhui provinces and southern Jiangxi Province in South China

The southern Jiangxi Province (SJP) and northern Jiangxi-southern Anhui provinces (NJSAP) are the two most important tungsten metallogenic districts in South China. The SJP district is a well-known tungsten producer in South China where distributes several ore concentrated areas such as the "Chongyi-Dayu-Shangyou", "Yudu" and "Longnan-Quanan-Dingnan" areas, with many large and super large tungsten deposits including the famous Xihuashan, Piaotang, Pangushan and Dajishan deposits. In recent years, major prospecting breakthrough for W-polymetallic resources has been made in the NJSAP district. Several large and super large W-Cu (Mo) deposits, such as the Dahutang, Zhuxi, Dongyuan and Baizhangyan deposits, are discovered. These deposits are all genetically associated with the Yanshanian (Mesozoic) granitic magmatism. In this study, a systematic comparison of the temporal and spatial distribution, petrology, geochronology, and geochemical characteristics of the tungsten-bearing granites between the SJP and NJSAP districts has been made, with an aim to improving the understanding of the petrogenesis of the granites and associated metal enrichment mechanisms in the two tungsten ore districts in South China. The following conclusions can be drawn: (1) The ages of the tungsten-bearing granites and associated mineralization are different in the two districts, in the SJP district the ages are mainly concentrated in 165-150 Ma, whereas in the NJSAP district it displays two age periods, one is 150-140 Ma (Late Jurassic-Early Cretaceous), and the other is 135-120 Ma (Early Cretaceous). (2) The tungsten-bearing granites from both the NJSAP and SJP districts are highly fractionated granitic rocks, but the SJP granites have experienced higher degree of fractional crystallization and more extensive fluid metasomatism than the NJSAP granites. (3) The petrogeneses of the tungsten-bearing granites from the two districts are different, those from the NJSAP district originated from partial melting of less mature sandstone-mudstone intercalated with meta-volcanic rocks of the Neoproterozoic Shuangqiaoshan Group which are both W and Cu enriched, in contrast those from the SJP district were likely derived from the highly mature, clay-rich mudstones of the Mesoproterozoic age which are only W enriched. In summary, the different source rocks with different metal enrichment features and different magmatic evolution and fractional degrees for the granites in the two districts might be the key factors that controlled the different matallogenic characteristics of tungsten ore deposits in the two districts in South China.