Insights into the distribution and mobility of metals in the sheeted dike complex formed at fast-spreading ridges (Pito Deep, EPR)
Date
2014-04-17
Authors
Zoeller, Khalhela
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Abstract
Hydrothermal fluid circulation is an important process in the formation and evolution of ocean crust. A tectonic window located at Pit Deep (NE corner Easter Microplate) provides an ideal location to examine a 3-dimensional view of ocean crust formed at the fast-spreading East Pacific Rise. This study focuses on the base metal (Cu, Ni, Mn, Co, Zn, and Pb) content of the bulk rock and mineral components in the sheeted dike complex. There is no observable trend of metal mobility with depth, geographic location, or dominant alteration phase. Secondary mineral analyses (using LA-ICP-MS) show that metals are redistributed throughout the sheeted dikes, entering into secondary sulphides, chlorite, and amphibole. Temperature and mineral stability is a primary control of metal mobility in these rocks. Due to highly variable metal concentrations and observed temperatures of alterations, the hydrothermal cell is suggested to be a continuously evolving system, and can cause the large variability observed in the metal distribution in the sheeted dikes.
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mid-ocean ridges, base metal mobility, fluid flow, base metal distribution, hydrothermal cells, water-rock interactions, sheeted dike complex, Pito Deep, East Pacific Rise, VMS deposits