Whole-rock geochemical data on basaltic to rhyolitic samples from 12 volcanic centers are used to constrain the role of continental crust in the genesis of magmas formed beneath the anomalously wide subduction-related volcanic arc in Ecuador. Relatively homogeneous, mantle-like, isotopic compositions across the arc imply that the parental magmas in Ecuador were produced largely within the mantl...

—The mid-Tertiary-age volcanoes, dikes, and sills of the Navajo volcanic field are classic and geologically-distinctive landforms of the Colorado Plateau. They are the products of structurally-controlled magma ascent, explosive eruptions, and deep post-eruptive exhumation. Igneous rock types include potassic lamprophyres, serpentinized tuffs, and exotic mafic and ultramafic intrusives. These ro...

The rocks of the Wadi Umm Gheig/El-Shush area in the central Eastern Desert of Egypt form part of the Nubian Shield, a component of the Neoproterozoic Pan-African Orogeny. The rocks have been divided into three units: (i) low-grade metamorphosed rocks, which consist of metavolcanic rocks interleaved with slices of ophiolitic melange; (ii) high-grade metamorphic rocks, which consist of syn-tecto...

Background: Robotic arms on landed spacecraft are typically designed to either (a) retrieve surface samples for analyses by the main spacecraft or (b), bring a mobile instrument package into contact with surface components. Yet the engineering data returned by a robotic arm while conducting these science support operations can themselves be used to investigate the physical properties of surface...

Vol ca nic rocks have formed along the length of the North Amer i can Cor dil lera dur ing the Neo gene and Qua ter nary pe ri ods. Vol ca nism of this age is dom i nantly al ka line and ex tends through out cen tral Brit ish Co lum bia and the south ern Yu kon Ter ri tory. Dis tinct prov inces of al ka line magmatism have been iden ti fied in BC, in clud ing the north ern Cor dil lera vol ca n...

Introduction: Study of the Martian crust by orbital spectroscopy and SNC meteorites has so far only recognized subalkaline volcanic rocks. However, Spirit rover measured high alkalis and low silica in picritic basalts on the Gusev plains [1,2], allowing the possibility that alkaline differentiates might occur. Isolated rocks having mildly alkaline compositions and distinctive spectra have now b...