Olivine-normative dolerite dikes from western South Carolina: Mineralogy, chemical composition and petrogenesis

Warner, R. D.; Snipes, D.S.; Hughes, S. S.; Steiner, J. C.; Davis, Michael W.; Manoogian, Peter R.; Schmitt, R. A.

doi:10.1007/bf00384717

Cited by 10 publications

(1 citation statement)

References 20 publications

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“…8), except that olivine diabase shows a little less overall enrichment in LILE and HFSE. Rare-earth-element patterns are quite different from those of olivine-normative tholeiitic diabases elsewhere in eastern North America (e.g., Warner et al 1985). In their overall chemistry, the dykes are quite different from the widespread early Jurassic tholeiitic basalt and diabase, even those that are olivine-normative (e.g.…”

Section: Olivine Diabase Dykesmentioning

confidence: 93%

Early Mesozoic Alkaline Mafic Dykes, Southwestern Nova Scotia, Canada, and Their Bearing on Triassic-Jurassic Magmatism

Pe‐Piper

Reynolds

2000

The Canadian Mineralogist

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Dykes of lamprophyre and alkaline olivine diabase cut the Cambro-Ordovician Goldenville Formation and the Carboniferous Wedgeport Pluton near Plymouth, southwestern Nova Scotia. 40 Ar/ 39 Ar geochronology yielded hornblende-biotite ages ranging between 231 ± 3 and 222 ± 3 Ma (mean 227 Ma) for the lamprophyres, and biotite ages of 209 ± 6 and 203 ± 15 Ma for the olivine diabase. Minerals present in the dykes include olivine (Fo 83), augite with a rim of titanaugite, kaersutite and titaniferous phlogopite. The whole-rock composition of both the lamprophyre and olivine diabase shows greater LILE and HFSE enrichment in the lamprophyres, but the relative abundances of these elements are remarkably similar in the two rock types, suggesting that they are comagmatic. Values of Nd (~+4) and Sr (~+5) are much more primitive than values for the widespread early Jurassic tholeiites. Pb isotope compositions for the lamprophyres fall near the Northern Hemisphere Reference Line; those of the olivine diabase are intermediate between the lamprophyres and more radiogenic Pb compositions typical of the Triassic alkaline dykes at Seabrook, New Hampshire, and the early Jurassic tholeiites; they may have experienced some contamination in the lower crust. The lamprophyres resemble, in age and chemical composition, other alkaline rocks of the Coastal New England province. The olivine diabases, apparently synchronous with the main Eastern North American tholeiites, represent renewed partial melting of the same mantle source, triggered by the thermal effect of the regional tholeiitic magma.

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Section: Olivine Diabase Dykesmentioning

confidence: 93%