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慢速扩张脊热液区烟囱体生长过程中常经历复杂的多阶段成矿事件，使得硫化物地球化学组成异常复杂，其成矿机理尚存在争议。德音热液区位于南大西洋中脊15°S附近，是一个典型的、发育于慢速扩张背景下的热液活动区。本文基于德音热液区烟囱体样品中硫化物微区元素组成，对烟囱体生长过程中热液流体物理化学条件演化进行了探讨。结果表明，该区烟囱体生长过程中，成矿流体经历了低温到高温的演化，硫化物微量元素富集特征由Mn、As、Pb等低温元素的富集向Cu、Se、Co等高温元素的富集转变，这主要受控于海水混合程度的变化。烟囱体生长的高温阶段，热液流体还发生了显著的相分离作用，导致了黄铁矿Tl/Pb(<0.02)、Sb/Pb(<0.5)比值的降低。本文研究结果为慢速扩张脊成矿流体演化及热液成矿机理提供了新的制约。
Abstract：In slow-spreading ridge hydrothermal fields, multiple stage mineralization events frequently occur, resulting in complicated geochemical compositions in precipitated sulfides. At present, the mineralization mechanism of hydrothermal sulfides in the hydrothermal system remains highly debated. The Deyin hydrothermal system, located on mid-Atlantic Ridge 15°S, is a typical hydrothermal field developed on slow-spreading ridge. In this study, in-situ geochemical compositions of sulfides from the Deyin field were analyzed systematically to reveal the mineralization fluid evolution. Results show that the hydrothermal fluid temperatures increased gradually during the chimney growth, and sulfide trace element characteristics evolved from low-temperature-element enrichment to high-temperature-element enrichment, which was controlled by variable seawater mixing contents. In high-temperature mineralization stage of the chimney growth, hydrothermal fluid experienced strong phase separation, resulting in low Tl/Pb(< 0.02), Sb/Pb(< 0.5) in pyrites. This study provided new constraints on hydrothermal fluid evolution and mineralization mechanism in slow-spreading ridge hydrothermal systems.
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基本信息:
DOI：10.16562/j.cnki.0256-1492.2025102802
中图分类号:P744
引用信息:
[1]张侠,孙治雷,侯晓帆,等.南大西洋中脊德音热液区成矿流体演化：来自硫化物微区元素组成的制约[J].海洋地质与第四纪地质,2025,45(06):59-67.DOI:10.16562/j.cnki.0256-1492.2025102802.
基金信息:
国家自然科学基金面上项目“冲绳海槽冷泉、热液共生区流体过程追溯与碳循环机理研究”（42476082）,“海洋甲烷拦截带对冷泉流体的消耗研究：来自南海东沙海域的观测与研究”（42176057）;国家自然科学基金集成项目“西太平洋流固界面物质循环及其演变集成研究”（92358301）; 国家地质调查专项（DD20230402）