Seafloor hydrothermal processes and deposits

海底热液过程和沉积物

• 批准号: 7069-2006
• 负责人: Scott, Steven
• 金额: $ 4.34万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=389464
• 关键词: Seafloor; hydrothermal; processes; deposits

This research aims to solve the mystery of how base and precious metal ore bodies are formed in volcanic rocks. Some of these deposits contain in excess of 100 million tons of ore. These are rare but very desirable because they represent the most cost effective means of producing metals such as zinc, copper, lead, silver and gold that are essential to modern society. Canadian examples such as Kidd Creek in Ontario and Brunswick #12 in New Brunswick would completely fill 10 Toronto Skydomes. Another aspect of my research is to determine the dispersal patterns of contaminants in sediments resulting from the ore-forming process. These contaminants (various metals, barium and arsenic) may provide vectors towards ores. Yet another is to understand the role of micro-organisms in the formation or iron and other base metal ores through the process of "biomineralization". It is generally considered that ore bodies now on land formed in ancient seas where seawater circulating through hot volcanic rocks became heated to 350°C (hot enough to melt lead). This hot sea water leached metals from the rocks and precipitated them as minerals where it discharged onto the sea floor. These metal-rich hot springs, known as "black smokers" because they resemble a dirty industrial process, are found in many regions of the world's oceans but none of them are accumulating metals in anywhere near the amounts of a Kidd Creek. From where, then, did all the metals in Kidd Creek come? The answer may be from fluids and gases, a so-called "magmatic fluid", issuing directly from the molten rock ("magma") that produces lavas from the depths of the Earth. As magmas rise within the seafloor crust, they cool and give off gases, mostly carbon dioxide and water. Some of these gases are trapped as tiny bubbles within the lavas. Careful work on such rocks from the sea bed off eastern Papua New Guinea with high resolution microscopes and micro analytical instruments has shown that accidentally trapped magmatic fluids are extremely rich in metals, many times more that the hot sea water of the black smokers.

这项研究旨在解开火山岩中贱金属矿体和贵金属矿体是如何形成的谜团，其中一些矿床蕴藏着超过 1 亿吨的矿石。生产对现代社会至关重要的锌、铜、铅、银和金等金属的加拿大例子，例如安大略省的基德溪和新不伦瑞克省的布伦瑞克#12将完全填满10个多伦多天穹。另一个目的是确定成矿过程中产生的沉积物中污染物的扩散模式，这些污染物（各种金属、钡和砷）可能为矿石提供载体，还有一个目的是了解微生物在铁的形成中的作用。和其他贱金属矿石通过“生物矿化”过程一般认为，现在陆地上的矿体是在古代海洋中形成的，海水循环通过热火山岩被加热到100℃。 350°C（温度足以熔化铅）。这些热海水从岩石中滤出金属，并将其沉淀为矿物质，并排放到海底。这些富含金属的温泉被称为“黑烟囱”，因为它们类似于一个。世界上许多海洋中都发现了肮脏的工业区，但没有一个海洋中的金属积累量接近基德河的量，那么，基德河中的所有金属是从哪里来的呢？可能来自流体和气体，即所谓的“岩浆流体”，直接从地球深处产生熔岩的熔融岩石（“岩浆”）中喷出。当岩浆在海底地壳内上升时，它们会冷却并释放出来。使用高分辨率显微镜和微型分析仪器对巴布亚新几内亚东部海床上的这些岩石进行仔细研究后发现，其中一些气体以微小气泡的形式被捕获。岩浆液中的金属含量极其丰富，比黑烟客的热海水还要多很多倍。