2,390 Myr Rb–Sr whole-rock for the Scourie dykes of north-west Scotland
作者： H. J. CHAPMAN
DOI: 10.1038/277642A0
关键词: North west 、 Isochron 、 myr 、 Metamorphic facies 、 Geology 、 Gneiss 、 Geochemistry 、 Lewisian complex 、 Facies 、 Overprinting
摘要: THE Scourie dyke swarm intrudes the Lewisian Complex in north-west Scotland. The structural state of these basic dykes is used to subdivide into pre-dyke ‘Scourian’ and post-dyke ‘Laxfordian’ complexes1. ∼2,700 Myr (refs 2–4) pyroxene-granulite facies Scourian gneisses Assynt area contain undeformed NW-trending dykes. Gneisses dykes, which underwent ∼1,900 5, 6) Laxfordian event, are now deformed metamorphosed at amphibolite facies. Previous K–Ar measurements for gave a minimum age injection 2,200 (ref. 7). Younger ages were thought reflect later overprinting. I report here Rb–Sr whole-rock isochron 2,390±20 (2σ) an initial 87Sr/86Sr ratio 0.7022±0.0001
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