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Magmatic development and tectonomagmatic models for the Solund-Stavfjord Ophiolite Complex, West Norwegian Caledonides

1989; Elsevier BV; Volume: 23; Issue: 3 Linguagem: Inglês

10.1016/0024-4937(89)90001-7

1872-6143

Kjell Petter Skjerlie, Harald Furnes, R.J. Johansen,

earthquake and tectonic studies

Geochemical variation and different extrusion rates of the Late-Ordovician Solund-Stavfjord Ophiolite Complex (SSOC) suggest both open and closed magma chambers. Closed chambers existed off axis and within a transform fault and are indicated by dykes and pillow lavas that evolved from high-MgO basalt to ferrobasalt by fractional crystallization of olivine, plagioclase and clinopyroxene. Hybrid magmas with ferrobasaltic composition represent open magmatic systems and are characterized by frequent eruptions of sheet flows. The SSOC is interpreted as representing either a normal or a propagating ridge-transform intersection (RTI). The propagating RTI model is favoured as it explains both the high frequency of ferrobasalt and uplift of ultramafic rocks to above the sea-level which is suggested by detrital ultramafics occurring in an ophiolitic mélange.