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K. H. Wedepohl 《Die Naturwissenschaften》1981,68(3):110-119
The oceanic earth's crust has mainly grown from magmatic productivity in spreading meridional ridges during the past 100–200 million years. The specific rock formed from these magmas is the ocean ridge tholeiitic basalt (ORT). From both melting experiments on peridotites and relative abundances of incompatible elements (La, Ce, Th, Rb etc.) the tholeiitic magmas can be explained as products of about 15% partial melting of abundant upper mantle rocks. A mobilization of incompatible elements very late in the mantle history has formed the different source rocks for magmas and ORT basalts depleted or slightly enriched in incompatible elements. 相似文献
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Relatively high strontium concentrations and their isotopic composition in Roman glass of the Imperial period indicate the
general use of shells as carbonate raw material. Lead, iron, and barium concentrations and lead isotopes of glass of the late
fourth century from Hambach and Gellep (western Germany) are conformable with the use of glass sand from Eifel rivers. Each
of three pairs of six simultaneously operating Roman glasshouses in the Hambach area made its own raw glass from different
quartz sands.
Received: 2 July 1999 / Accepted in revised form: 13 December 1999 相似文献