Geochemical Characteristics and Sedimentary Environment of Paomaping Manganese Deposit in Changyang,Western Hubei Province
Liu Hai
Qi Shuanglin
Fan Jiulin
Guo Wei
Chen Aizhang
Zhang Shujie
Abstract：The Nanhua manganese deposit in Changyang anticline of western Hubei is a Datangpo-type manganese deposit,and its metallogenic age is precisely in the interglacial period of the Neoproterozoic Snowball Earth event.Under the background of the breakup of the Rodinia supercontinent,there is genetic relationship among the climate change,rift basin and manganese mineralization in the Datangpo period.In order to elaborate the control of paleoclimate,sedimentary environment and manganese source on the sedimentary mineralization of large-scale manganese deposits,restore the metallogenic process of Datangpo-type manganese deposits in western Hubei,this study selected Paomaping manganese deposit in Changyang area of western Hubei as the research object,and carried out a comprehensive study on its geochemical characteristics.The results show that the Mn/Fe ratio of manganese carbonate ore is high,the separation of Mn and Fe was very thorough during the deposition process,the oxidation-reduction sensitive elements V and U are depleted,and Mo is enriched,revealing that the Datangpo period is an oxidation-weak oxidation sedimentary environment.Paleo-oxygenation facies such as δU,Uau,Th/U,V/Cr,and Co/Ni indicate that the Datangpo period was an oxygen and weak oxidation sedimentary environment.The Al and Ti contents of the Changyang anticline rhodochrosite are slightly higher than those in the Hunan,Guizhou and Chongqing areas,indicating that the content of terrigenous debris in the manganese deposits in the northern margin of Yangtze is higher than that in the southeastern margin of Yangtze and the depth of its sedimentary water is relatively shallow or closer to the source.The study of CIA index shows that the weathering intensity of Datangpo period in Changyang anticline is medium,rhodochrosite and carbonaceous mud(shale)rock are characterized by the low Al/(Al+Mn+Fe)ratios,positive Eu anomalies,LREE enrichment,Nb/Ta,Zr/Hf,Y/Ho ratio and La/Yb-Ce/La,(Co+Ni+Cu)X10-Fe-Mn,Zr-Cr diagram analyses of manganese carbonate indicate that the source of manganese is mainly from deep hydrothermal fluid,supplemented by land-derived manganese,and it was sourced from the hydrothermal sedimentary in the mineralization period.By studying the CIA index,Sr/Cu,Rb/Sr,Sr,Sr/Ba values,it is considered that the Datangpo period of Changyang anticline is a warm and humid climate environment.The mineralization of manganese carbonate is obviously coupled with redox environment,manganese source,paleoclimate and paleosalinity.
Keywords：Paomaping manganese depositgeochemistrypaleoclimaticsedimentary environmentmanganese source
Publication Date：2025-01-14
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：19( 58-76 )