The Crummock Water aureole : a zone of metasomatism and source of ore metals in the English Lake District
Cooper, D.C.; Lee, M.K.; Fortey, N.J.; Cooper, A.H.; Rundle, C.C.; Webb, B.C.; Allen, P.M.. 1988 The Crummock Water aureole : a zone of metasomatism and source of ore metals in the English Lake District. Journal of the Geological Society, 145 (4). 523-540. 10.1144/gsjgs.145.4.0523Full text not available from this repository. (Request a copy)
The Crummock Water aureole, an ENE-trending elongate zone of bleached and recrystallized Skiddaw Group rocks, 24 km in length and up to 3 km wide, is a zone in which pervasive metasomatism has modified the composition of the dominantly siltstone and mudstone lithologies. The bleached rocks show a substantial net gain of As, B, K and Rb and loss of Cl, Ni, S, Zn, H2O and C. Carbon loss is responsible for the bleaching. There are smaller and more localized net losses of Cu, Fe, Li and Mn, and gains of Ca, F and Si, whilst Co, Pb and REE are at least locally redistributed. Many chalcophile elements show evidence of initial widespread depletion and subsequent local enrichment. The mineralogy of the rocks is little affected by the geochemical changes. Like their counterparts outside of the bleached zone, the metasomatized rocks consist essentially of quartz, chlorite, muscovite, paragonite and rutile. Small aggregates and porphyroblasts of white mica and chlorite are developed. The metasomatism, which was accompanied by tourmaline veining, is superimposed on a contact metamorphic event. It post-dates the main Caledonian cleavage but pre-dates late Caledonian minor folds.
|Programmes:||BGS Programmes > Geology and Landscape Northern|
|NORA Subject Terms:||Earth Sciences|
|Date made live:||20 May 2011 08:56|
Actions (login required)