下雷-东平锰矿带矿床特征和成因探讨

下雷-东平锰矿带是我国重要的锰矿矿集区。在矿集区典型锰矿床的野外工作基础上,对含锰岩系和矿石开展了岩石学、岩石化学、微量元素地球化学分析研究,比较了同一锰矿带的下雷式、东平式两类锰矿床特征。结合前人区域构造资料,探讨了下雷式、东平式两类锰矿成因。研究认为下雷式锰矿形成于被动大陆边缘,热水作用参与了锰矿的形成;而东平式锰矿形成于被动大陆边缘向前陆盆地过渡带,成矿过程中火山活动强烈,推测东平锰矿的沉淀富集作用与海底火山喷发具有一定的相关性。

Characteristics and genesis of the deposits in the Xialei-Dongping manganes ore belt of Guangxi Province

The Xialei-Dongping manganese ore belt is an important ore concentration area in China. Based on field work on the typical Mn-deposits, we have conducted research on petrological characteristics, major element content, and trace element content of ore-bearing formation. We compared the characteristics of Xialei-type manganese deposits and Dongping-type manganese deposits which formed in the same ore-forming belt. Combined with regional tectonic data from previous studies, we explored the genesis of the two types of deposits. Our research suggest that the Xialei-type Mn-deposits formed in a passive continental margin, where hydrothermal activity played an important role in the formation of Mn-deposits, while the Dongping-type Mn-deposits were generated in a transition from a passive continental margin to a foreland basin where volcanic activity was intensive. We infer that the formation of the Dongping-type Mn-deposits was related to volcanic eruptions at the seafloor.