This chapter describes geochemical and petrographic characteristics of the central belt of the archean Dongwanzi ophiolite complex. The Dongwanzi ophiolite of the North China craton represents the oldest known complete section of oceanic crust. It consists of three main northeast striking outcrop belts, and numerous related blocks in tectonic mélange. The ophiolite is broken into three main thrust slices, including the NW Belt, Central Belt, and the SE Belt. In this contribution aspects of all belts are described in the chapter, but focus is given on the Central Belt. All of the belts are metamorphosed to at least greenschist facies and typically amphibolite facies, with conditions approaching granulite in the west. Amphibole-bearing pyroxenites (NC2001-13-1) from the central belt include mineral assemblages of primary coarse-grained hornblende and smaller primary titanite grains in a fine-grained altered matrix. The cumulate layer represents the transition zone between the lower ultramafic cumulates and uppermafic assemblages. The lower part of the sequence consists of orthocumulate pyroxenite, dunite, wehrlite, lherzolite and websterite, and olivine gabbro-layered cumulates.
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