Trace element analyses (first-series transition elements, Ti, Rb, Sr, Zr, Y, Nb, and REE) were carried out on whole rocks and minerals from 10 peridotite samples from both Conical Seamount in the Mariana forearc and Torishima Forearc Seamount in the Izu-Bonin forearc using a combination of XRF, ID-MS, ICP-MS, and ion microprobe. The concentrations of incompatible trace elements are generally lo...

The Cenozoic Hannuoba basaltic province, 200 km northwest of Beijing, China, is composed of intercalated tholeiitic, transitional and alkalic basalts. Although the alkalic basalts contain abundant upper mantle xenoliths, they range in MgO content from 5.7 to 10.6% MgO. Most of the major and trace element abundance variations in the alkalic basalts can be explained by segregation of a clinopyrox...

The Emperor Seamount-Hawaiian island chain is thought to originate from melting of a heterogeneous mantle plume, but the composition of the plume has always been inferred from the compositions of the erupted lavas. It has been suggested that recycled (i.e. previously subducted) basaltic oceanic crust (with or without sediments) is part of this plume and responsible for the enriched isotopic com...

Liquidus phase relationships determined on the join anorthite-forsterite-quartz at 20 kbar show primary phase fields for quartz (q), forsterite 0Co), enstatite (en), spinel (sp), anorthite (an), sapphirine (sa), and corundum (cor). Increasing pressure causes (1) the f o and an primary phase fields to contract, (2) the en, q, and cor fields to expand, (3) t h e f o e n boundary line to move away...