A two-dimensional, one by two-kilometer section through the seafloor was simulated with a numerical model to investigate coupled fluid and heat flow resulting from basalt intrusions in a buried spreading center. Boundary and initial conditions and physical propertie s of both sediments and basalt were constrained by field surveys and drilling in the Guaymas Basin, central Gulf of California. Pa...

Flood basalt flows of the Columbia River Basalt Group commonly exhibit well-developed colonnade and entablature structures formed during cooling of individual flows. The colonnade refers to the well-defined columnar structure of many flows, which appears in the lowermost 10% to 30% and, in places, the uppermost 10% to 20%. Entablature refers to those parts of a flow that have smaller column dia...

Introduction: Data from the MGS Thermal Emission Spectrometer (TES) has shown that surface type 1 (ST1) materials, interpreted as basalt, dominate the ancient crust in the southern highlands of Mars [1]. Large expanses of surface type 2 (ST2) materials in the northern lowlands have been variously interpreted as andesite [1, 2], oxidized crystalline basalt [3], or partly weathered basalt [4]. Th...

Harrat Lunayyir is a basaltic volcanic field in NW Saudi Arabia. Lava flows are basaltic to basanitic in composition, and the Holocene flows are alkali olivine basalts. The volcanic field contains about 50 cones that were constructed on Precambrian crystalline rocks along an N-S axis. The dominantly basaltic lavas of Harrat Lunayyir have been divided based on their erosion characteristics into ...

[1] High-alumina (HA) mare basalts are a unique group of the lunar sample collection. Sample geochemistry indicates that these basalts are derived from sources composed of late-stage cumulates from the Lunar Magma Ocean (LMO). Their aluminous nature suggests their sources contained significant plagioclase, which has implications regarding the efficiency of plagioclase separation from earlier fo...

Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and...

Grande Ronde Basalt (GRB) lavas represent the most voluminous eruptive pulse of the Columbia River-Snake River-Yellowstone hotspot volcanism. With an estimated eruptive volume of 150,000 km, GRB lavas form at least 66% of the total volume of the Columbia River Basalt Group. New Ar/Ar dates for GRB lavas reveal they were emplaced within a maximum period of 0.42 ±0.18 My. A well-documented strati...

We examine the role that flood basalt eruptions may have played during times of mass extinction through the release of volcanic gases. Continental flood basalt provinces have formed by numerous eruptions over a short period of geologic time, characteristically a fewmillion years.Within this period, a short-lived climactic phase that lasts about 1Ma typically emplaces a large proportion of the l...

BACKGROUND We studied the meiofauna community at deep-sea hydrothermal vents along a gradient of vent fluid emissions in the axial summit trought (AST) of the East Pacific Rise 9°50'N region. The gradient ranged from extreme high temperatures, high sulfide concentrations, and low pH at sulfide chimneys to ambient deep-sea water conditions on bare basalt. We explore meiofauna diversity and abund...

The pyroxene composition of basaltic rocks from the Coloured Series and Exotic blocks in the Neyriz area are discussed. Comparison has been made with equivalent rocks from Oman. The clinopyroxene compositions are in cognation with trace and rare-earth element analyses which definately confirm the occurrence of three different trends in basic lavas: I-Depleted tholeiite, 2-Transitional basal...