? Quick Search: ? ? ? Advanced Search
Ma Yao,Wang Xiaoyuan,Chen Shuai,Yin Xuebo,Zhu Bowen,Guo Kun,Zeng Zhigang. 2019. Origin of Cu in the PACMANUS hydrothermal field from the eastern Manus back-arc basin: evidence from mass balance modeling. Acta Oceanologica Sinica, 38(9):59-70
Origin of Cu in the PACMANUS hydrothermal field from the eastern Manus back-arc basin: evidence from mass balance modeling
东马努斯海盆PACMANUS热液区Cu的物质来源:质量守恒模拟证据
Received:September 11, 2018??
DOI:10.1007/s13131-019-1475-z
Key words:back-arc basin??mass balance model??PACMANUS hydrothermal field??source of Cu
中文关键词:??弧后盆地??质量守恒模式??PACMANUS热液区??Cu的物质来源
基金项目:
Author NameAffiliationE-mail
Ma Yao?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China?
mayao@qdio.ac.cn?
Wang Xiaoyuan?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China?
?
Chen Shuai?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China?
?
Yin Xuebo?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China??
Zhu Bowen?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
University of Chinese Academy of Sciences, Beijing 100049, China?
?
Guo Kun?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
Ocean Science Isotope and Geochronology Center, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China?
?
Zeng Zhigang?Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
University of Chinese Academy of Sciences, Beijing 100049, China?
?
Hits:?7
Download times:?22
Abstract:
??????Hydrothermal precipitates associated with active vents in the eastern Manus Basin, an actively opening back-arc basin in the Bismarck Sea, Papua New Guinea, are among the most Cu-rich on the modern seafloor. The volcanic rocks associated with this mineralization may be insufficiently enriched in Cu to account for the Cu content of the sulfides by simple leaching. The PACMANUS hydrothermal field lies in the eastern portion of the eastern Manus Basin. Mass balance modeling of the PACMANUS hydrothermal system indicates that simple leaching of a stationary reaction zone (0.144 km3) by hydrothermal fluids cannot yield the Cu found in associated sulfide deposits because unacceptably high leaching, transportation and precipitation efficiencies are required to derive the Cu in sulfides by leaching processes. With 100% leaching, transport and precipitating efficiency, 0.166 km3 of volcanic rocks would need to be leached to account for the Cu budget of hydrothermal sulfide deposits. The key requirement for forming metal-rich magmatic fluids is a large amount of metals available to enter the exsolved vapor phase. Magmas generated in the eastern Manus Basin inherently have high fO2 because of metasomatism of the mantle source by oxidized materials from the subducted slab, leading to copper enrichment in the magma chamber. Moreover, the presence of Cu in gas-rich melt inclusi on bubbles in Pual Ridge andesite is evidence that degassing and partitioning of Cu into the magmatic volatile phase has occurred in the eastern Manus Basin. Numerical mass balance modeling indicates that approximately 0.236 Mt Cu was potentially transferred to the hydrothermal system per cubic kilometer magma. Magmatic degassing seems to play a more significant role than leaching.
中文摘要:
??????东马努斯海盆位于巴布亚新几内亚的俾斯麦海域,是一个正在扩张的弧后盆地,与其活动热液喷口相关的热液产物,是现代海底系统中富含铜最丰富的矿产资源之一。火山岩与这种成矿作用有着密切的关系,然而通过海水对火山岩的淋滤作用是否可以为富含Cu的硫化物提供充足的Cu元素。PACMANUS热液区位于东马努斯海盆,质量守恒模拟在该热液系统的应用表明,由于水岩反应中较低的淋滤、转移和沉淀效率,通过热液流体对稳定反应区(0.144 km3)的简单淋滤无法满足硫化物矿床中Cu的需求。即使在100%的淋滤、转移和沉淀效率条件下,为了满足PACMANUS热液区硫化物中Cu的总量,仍需要0.166 km3体积的火山岩参与淋滤作用。
形成富含金属元素的岩浆流体的关键在于金属元素可以在挥发分中富集。首先,俯冲物质对地幔楔的交代作用,导致了东马努斯海盆地区生成的岩浆具有较高的氧逸度,进而使其岩浆房中富集Cu元素。其次,Pual Ridge的安山岩包裹体的气泡中富含Cu元素,进一步证实了在东马努斯海盆,Cu元素通过岩浆脱气作用向挥发分中运移。数值模拟结果显示,每1 km3体积的岩浆就可能向热液系统中运移0.236 Mt Cu。因此,岩浆脱气作用可能比淋滤作用更显着。
HTML View Full Text ??View/Add Comment??Download reader
Close