Partial Melting Experiments of Peridotite + CO2 at 3 GPa and Genesis of Alkalic Ocean Island Basalts

Near-solidus Melting of the Shallow Upper Mantle: Partial Melting Experiments on Depleted Peridotite

We present the results of melting experiments on a moderately depleted peridotite composition (DMM1) at 10 kbar and 1250±1390 C. Specially designed experiments demonstrate that liquids extracted into aggregates of vitreous carbon spheres maintained chemical contact with the bulk charge down to melt fractions of 0 02±0 04 and approached equilibrium closely. With increasing melt fraction, SiO2, F...

Major element chemistry of ocean island basalts — Conditions of mantle melting and heterogeneity of mantle source

Calculation of Peridotite Partial Melting from Thermodynamic Models of Minerals and Melts, IV. Adiabatic Decompression and the Composition and Mean Properties of Mid- ocean Ridge Basalts

Composition, mean pressure, mean melt fraction, and crustal thickINTRODUCTION ness of model mid-ocean ridge basalts (MORBs) are calculated Comparison of observed basalt compositions with the using MELTS. Polybaric, isentropic batch and fractional melts predictions of polybaric mantle melting models places from ranges in source composition, potential temperature, and final important restrictions...

Generation of mid-ocean ridge basalts at pressures from 1 to 7 GPa

We propose a model for the generation of average MORBs based on phase relations in the CaO-MgO-Al2O3-SiO2-CO2 system at pressures from 3 to 7 GPa and in the CaO-MgO-Al2O3-SiO2-Na2OFeO (CMASNF) system at pressures from 0.9 to 1.5 GPa. The MELT seismic tomography (Forsyth et al., 2000) across the East Pacific Rise shows the largest amount of melt centered at 30-km depth and lesser amounts at grea...

THE GEOCHEMISTRY OF CENOZOIC BASALTS AND PERIDOTITE XENOLITHS FROM HANNUOBA REGION, EASTERN CHINA: IMPLICATION FOR THEIR PETROGENESIS AND SUBCONTINENTAL MANTLE HETEROGENEITY by

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...