Along‐strike variation of the sheeted dike complex in the Oman Ophiolite: Insights into subaxial ridge segment structures and the magma plumbing system

摘要: [1] Along-strike variations of the 60-km-long sheeted dike complex in northern Oman Ophiolite were studied order to understand shallow magma plumbing system beneath fossil fast spreading ridge. The presence numerous dikes intruding into layered gabbro defines end paleoridge segment at Wadi Fizh. postulated center is located Thuqbah, which has a thicker Mono transition zone than elsewhere along segment. Aphyric predominate dikes, 99% are simple, while multiple and composite few. thickness 1511 ranges from 13 m, with an average 71.3 cm. Restored trends 30-km-long half display NS trending north domain NNE-NS south bordered Bani Umar al Gharbi. In boundary, gradually change strikes or mutually intrusive. Dike thickens northward largest peak Fizh small Most have bulk Mg# 55–66, overlaps majority MORB. Less common, highly evolved 34–40 characterize domain. Thicker (>3 m) tend high Mg#, thinner (<2 variable Mg#. regional whole rock compositions can be explained by secular variation structures comparable third-order present mid-ocean ridge spanning few tens thousands years. Initially, segment-long melt lens developed axis, fed long thick With decreasing supply magma, split up smaller lenses DEVAL that former dikes. Cut-off source changed composition evolved, low-Mg# magmas, subsequently intruded as short Meanwhile, main continued feeding high-Mg# maintained larger size intermittent deep chambers.