(1. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長沙 410083;
2. 中南大學(xué) 有色資源與地質(zhì)災(zāi)害探查湖南省重點實驗室，長沙 410083;
3. 安徽省地質(zhì)調(diào)查院，合肥 230001)
摘 要: 江南造山帶新元古變基性巖為區(qū)域構(gòu)造事件和演化模型的建立提供地質(zhì)依據(jù)。對江南造山帶東段皖南鶴城地區(qū)變玄武質(zhì)巖的地球化學(xué)及巖石成因進行研究。鶴城變玄武巖呈北東—南西向沿瑤里—鶴城—江潭一帶分布。元素地球化學(xué)的研究表明:休寧鶴城變玄武巖同科馬提質(zhì)玄武巖及島弧玄武巖相類似;富集Rb、Ba、Th、U等強不相容元素，虧損高場強元素Nb和Ta，指示其成因可能與富集地幔的部分熔融有關(guān)，同時有地殼物質(zhì)的混染，其可能屬于皖南伏川蛇綠巖西延組成部分，與伏川蛇綠巖組成一個弧后雜巖帶，形成于與俯沖有關(guān)的弧后小洋盆環(huán)境。結(jié)合區(qū)域資料，表明新元古代板塊俯沖、島弧巖漿活動以及拼合是江南造山帶形成的比較合理的構(gòu)造演化過程。
關(guān)鍵字: 江南造山帶東段;鶴城;變玄武巖;科馬提質(zhì)玄武巖;島弧玄武巖
（1. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
2. Hunan Key Laboratory of Non-ferrous Resources and Geological Hazard Detection,
Central South University, Changsha 410083, China;
3. Bureau of Geology and Mineral Resources Exploration of Anhui Province, Hefei 230001, China）
Abstract:The Neoproterozoic meta-mafic rocks of the Jiangnan Orogen in South China provide a critical geological record for unraveling regional tectonic history and testing previously proposed tectonic models. An integrated study of geochemistry and petrogenesis was carried out for the meta-basaltic rocks from Hecheng, south Anhui Province of the eastern Jiangnan Orogen, which distributed along the NE-SW Yaoli-Hecheng-Jiangtan line. The geochemical features of the Hecheng meta-basalt are similar to those of Komatiitic basalt as well as island arc basalt. The trace elements features, such as the enrichment in strongly incompatible elements (Rb, Ba, Th and U) and the depletion in high field strength elements (Nb and Ta), indicate that the Hecheng meta-basalt is derived from partial melting of enriched mantle, with crust materials contamination, suggesting that Hecheng meta-basalt is a westward extension of Fuchuan ophiolite in southern Anhui Province, and constitute a back-arc complex belt with Fuchuan ophiolite, attributed to the back arc basin environment related to the subduction. Integrating this information with previous studies, the plate subduction-island arc magmatism-assembly model is a more appropriate geodynamic interpretation for the Neoproterozoic tectonic evolution of South China.
Key words: Eastern Jiangnan orogen; Hecheng; meta-basalt; Komatiitic basalt; island arc basalt
