Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21-25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile e...

Geochemical modeling using the basalt composition analyzed at the Vega 2 landing site indicates that intermediate to silicic liquids can be generated by fractional crystallization and equilibrium partial melting. Fractional crystallization modeling using variable pressures (0.01 GPa to 0.5 GPa) and relative oxidation states (FMQ 0 and FMQ -1) of either a wet (H2O = 0.5 wt%) or dry (H2O = 0 wt%)...

The Cenozoic Mormon Mountain Volcanic Field (MMVF) of northern Arizona is situated in the transition zone between the Basin and Range and the Colorado Plateau. It is composed of alkalic to sub-alkalic basalts and calcalkalic andesites, dacites, and rhyodacites. Despite their spatial and temporal association, the basalts and the calcalkalic suite do not seem to be co-genetic. The petrogenesis of...

Liquidus phase relationships determined on the join CaAIzSi20 8 (anorthi te)-MgzSiO 4 (forsteri te)-SiO 2 (quartz) at 10 kbar show that increasing pressure causes the forsterite and anorthite primary phase fields to shrink and the spinel, enstatite and silica fields to expand. The boundary line between the enstatite and forsterite fields and that between the enstatite and quartz fields both mov...

We have determined the metallographic cooling rates for 13 IVA irons using the most recent and most accurate metallographic cooling rate model. Group IVA irons have cooling rates that vary from 6600 C/Myr at the low-Ni end of the group to 100 C/Myr at the high-Ni end of the group. This large cooling rate range is totally incompatible with cooling in a mantled core which should have a uniform co...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. [1] We examine mantle melting, fractional crystallization, and melt extraction beneath fast slipping, segmented oce...

Introduction: Although the Lunar Magma Ocean (LMO) hypothesis has achieved wide acceptance in the lunar science community, it has never been fully tested experimentally. Presented here are the first results of equilibrium crystallization experiments using the Taylor Whole Moon (TWM) composition [1]. The first mafic cumulates in this LMO are dominated by forsteritic olivine, low-Ca pyroxene and,...