Campbell, S. D. G., Reedman, A. J., Howells, M. F., Mann, A. C. (1987) The emplacement of geochemically distinct groups of rhyolites during the evolution of the Lower Rhyolitic Tuff Formation caldera (Ordovician), North Wales, U.K. Geological Magazine, 124 (6) 501-511 doi:10.1017/s0016756800017349
Reference Type | Journal (article/letter/editorial) | ||
---|---|---|---|
Title | The emplacement of geochemically distinct groups of rhyolites during the evolution of the Lower Rhyolitic Tuff Formation caldera (Ordovician), North Wales, U.K. | ||
Journal | Geological Magazine | ||
Authors | Campbell, S. D. G. | Author | |
Reedman, A. J. | Author | ||
Howells, M. F. | Author | ||
Mann, A. C. | Author | ||
Year | 1987 (November) | Volume | 124 |
Issue | 6 | ||
Publisher | Cambridge University Press (CUP) | ||
DOI | doi:10.1017/s0016756800017349Search in ResearchGate | ||
Generate Citation Formats | |||
Mindat Ref. ID | 253702 | Long-form Identifier | mindat:1:5:253702:7 |
GUID | 0 | ||
Full Reference | Campbell, S. D. G., Reedman, A. J., Howells, M. F., Mann, A. C. (1987) The emplacement of geochemically distinct groups of rhyolites during the evolution of the Lower Rhyolitic Tuff Formation caldera (Ordovician), North Wales, U.K. Geological Magazine, 124 (6) 501-511 doi:10.1017/s0016756800017349 | ||
Plain Text | Campbell, S. D. G., Reedman, A. J., Howells, M. F., Mann, A. C. (1987) The emplacement of geochemically distinct groups of rhyolites during the evolution of the Lower Rhyolitic Tuff Formation caldera (Ordovician), North Wales, U.K. Geological Magazine, 124 (6) 501-511 doi:10.1017/s0016756800017349 | ||
In | (1987, November) Geological Magazine Vol. 124 (6) Cambridge University Press (CUP) | ||
Abstract/Notes | AbstractRhyolites in the vicinity of Snowdon (North Wales) are intimately associated with the evolution of the Lower Rhyolitic Tuff Formation (LRTF) caldera of Ordovician (Caradoc) age. They occur as deep-seated dykes, sills and small stocks, shallow-level intrusive domes, and domes extruded within a predominantly shallow-marine environment. Extrusion occurred during three main phases, indicating the episodic availability of rhyolite magma. The rhyolites can be divided on their trace element ratios (e.g. Nb/Zr) into five main groups. Extrusive representatives indicate that each group correlates strongly with a single phase of rhyolite extrusion. Within each group, the distribution and variation of intrusive form with stratigraphic level suggests that geochemically similar rocks were emplaced at approximately the same time. Consequently, the groups represent discrete magma compositions tapped from the evolving Snowdon subvolcanic magma system. Differences in distribution of the groups reflect changes in structural controls of emplacement before and after development of the LRTF caldera. |
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