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Late Caledonian dyke-swarms of northern Britain; spatial and temporal intimacy between lamprophyric and granitic magmatism around the Ross of Mull Pluton, Inner Hebrides


, : Late Caledonian dyke-swarms of northern Britain; spatial and temporal intimacy between lamprophyric and granitic magmatism around the Ross of Mull Pluton, Inner Hebrides. Geologische Rundschau 76(3): 805-826

Numerous sheet intrusions in Iona and western Mull (Scotland) range from basic calc-alkaline lamprophyres (45% SiO2;mg number 65–75%; Thornton-Tuttle differentiation index [DI] 45%), through intermediate (microdioritic) compositions (malchites) to microgranitic porphyries (70% SiO2; DI 85%). Well-defined major element trends, remarkably consistent normalized multielement patterns, and strong linear correlations between homologous elements (e.g. Sc-V-Fe-Ti, Mg-Ni-Cr) suggest that these sheets form one cogenetic suite. Although Rb-Sr systems have been disturbed by Archaean country-rock contamination, isotopic signatures and field evidence suggest that sheet emplacement bracketed that of the 414 Ma Ross of Mull granitoid pluton: a few late sheets cut the pluton; exceptionally well-developed multiple and composite sheets provide clear evidence forsimultaneity of lamprophyric and granitic magmas; and an early group of sheets appears to be metamorphosed by the pluton. The composite sheets comprise lamprophyric borders around thicker microgranitic quartz-feldspar-porphyries, each rock-type carrying xenocrysts or xenoliths of the other. Mutual contacts mark wide discontinuities in major element composition, and sites of local hybridisation, yet close trace element similarities strongly imply the lamprophyres and porphyries are cogenetic. Least-squares modelling further shows that fractionation of actual phenocrysts in one lamprophyric margin could reproduce the porphyry with which it is in intimate contact. The most primitive (mg>70%) lamprophyres combine very high K, Rb, Th and Ba with MORB-like contents of Cr, Ni, Ti, Y, and Sc, implying a substantial mantle-derived component, and in some cases near-primary status, but not precluding some crustal participation. Biotite- and hornblende-lamprophyres are locally heteromorphic. Discontinuities in some chemical trends, field evidence, and initial87Sr/86Sr ratios (0.706), imply more complex interactions of fractionation and hybridisation with lamprophyric parent magmas, plus crustal contamination, in the genesis of the intermediate and microgranitic rocks. The association between lamprophyric and granitic magmatism in Iona/western Mull is not therefore fortuitous but genetic. The lamprophyres have an undoubted role in the genesis not merely of the microgranitic minor intrusions but probably of the granite pluton itself.

US$19.90

DOI: 10.1007/bf01821065


Other references

Fortoul, G.N.rdi, R., 1979: Additions to the fungus flora of the upper Alps: Rutstroemia remyi nov. sp. (Ascomycetes). Bulletin trimestriel de la Societe mycologique de France5(2): 77-81

Emery, C.; Young, R.M.; Morgan, D.B.; Hay, A.W.; Tete-Donker, D.; Rubython, J., 1984: Tubular damage in patients with hypokalaemia. Severe hypokalaemia is occasionally associated with gross changes in renal tubular function. We have looked for lesser degrees of renal tubular damage in unselected patients with hypokalemia by measuring the urine excretion of total protein, album...

Bukovski, T., 1954: Technique for collecting spores of cap fungi for germination purposes. At the Mycological Laboratory, Warsaw, Poland, spores of Agaricus hortensia were collected on a dish placed under the sporophore growing on its natural substrate or removed from the bed together with spawn and earth and grown in a sterilized tube...

Felberg, J.; Johnson, P., 1998: Characterization of recombinant CD45 cytoplasmic domain proteins. Evidence for intramolecular and intermolecular interactions. CD45 is a transmembrane two-domain tyrosine phosphatase required for efficient signal transduction initiated by lymphocyte antigen receptors. As with most transmembrane two-domain phosphatases, the role of the second phosphatase domain is unclear....

Ibragimova, G.T.; Kivaeva, L.S.; Kutyshenko, V.P., 1999: Study of the compact denatured state of a protein by molecular dynamics simulation. The native state can be considered as a unique conformation of the protein molecule with the lowest free energy of residue contacts. In this case, all other conformations correspond to the denatured state. The degree of their compactness varies si...

Weaver F.M.; Wise S.W., 1973: Origin of Cristobalite-Rich Tertiary Sediments in Atlantic and Gulf Coastal Plain. The American Association of Petroleum Geologists Bulletin 57(9): 1840

Pyzik, Z.; Karczmarz, A.; Dubiel, J.P., 1975: Hemodynamics of the right cardiac ventricle and pulmonary circulation and the functional state of the lungs in patients with chronic cor pulmonale syndrome. Folia Medica Cracoviensia 17(1): 11-20

Hentschel G.; Tillmanns E.; Hofmeister W., 1985: Hannebachite, natural calciumsulfite hemihydrate, CaSO3X1/ 2 H2O. Neues Jahrbuch fuer Mineralogie Monatshefte

Milgrom, L.R., 2002: Vitalism, complexity and the concept of spin. Vital Force is a concept that has suffered at the hands of the current medical model. An attempt is made to show how it might be possible to explain Vital Force in terms of complexity theory. A metaphor is introduced for the operation of Vital For...

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