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Metasomatism and the formation of greisen in Grainsgill, Cumbria, England
Author(s) -
Roberts D. E.
Publication year - 1983
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350180104
Subject(s) - greisen , metasomatism , geology , geochemistry , hornfels , quartz , hydrothermal circulation , amphibole , metamorphism , mineralogy , tourmaline , fluid inclusions , biotite , paleontology , mantle (geology)
A section of hornfelsed Skiddaw Slate adjacent to the margin of the Grainsgill Greisen is described and chemical analyses of the various rock types presented. The results confirm that hydrothermal fluids liberated K and Na from the granite to produce the greisen. This gave rise to K metasomatism of the adjacent hornfels and to retrogressive metamorphism over a radius of 200m from the intrusion. Na leached from the hornfels near the intrusion and that liberated during the formation of the greisen are probably the sources of the Na in the brines recorded in fluid inclusions within the nearby quartz‐tungsten veins.