edge of the character and chemical composition of the rocks of the moon, and thus possibly a decision of the question of the volcanic or non-volcanic origin of its "craters," might conceivably be arrived at by astronomers, through study of the maximum polarization angle of various portions of the moon's surface, such as the floors of the "seas" and the "walled plains." From the determination of...

neyshabour turquoise mine is located in northwest of neyshabour, southern quchan volcanic belt. eocene andesite and dacite forming as lava and pyroclastic rocks cover most of the area. subvolcanic diorite to syenite porphyry (granitoids of magnetite series) intruded the volcanic rocks. both volcanic and subvolcanic rocks are highly altered. four types of alteration are recognized including: sil...

This study investigates petrology and major, minor, and rare earth elements ‎geochemistry of ‎East Iranian Eocene–Oligocene volcanic rocks in Sistan suture ‎zone, to examine their ‎petrogenesis and magma evolution. The volcanic rocks include andesite, trachy-andesite, dacite ‎and rhyolite. ‎These calc-alkaline rocks of high-K series are enriched in Large ‎Ion Lithophile ‎Elements of Rb and Ba a...

[1] In the Inner Basin of the Columbia Hills, Gusev Crater is Home Plate, an 80 m platform of layered clastic rocks of the Barnhill class with microscopic and macroscopic textures, including a bomb sag, suggestive of a phreatomagmatic origin. We present data acquired by the Spirit Mars Exploration Rover by Alpha Particle X-Ray Spectrometer (APXS), Mössbauer Spectrometer, Miniature Thermal Emiss...

The collision of India with Asia, one of the most profound tectonic events to have occurred in past 100 m.y., is thought to have had geological, geochemical, and climatological consequences of global extent. Surprisingly the age of initiation of this collision remains poorly constrained. Estimates range from the Late Cretaceous (.65 Ma) to latest Eocene (,40 Ma), with little consensus in betwee...

The central Oregon section of the Cascade Range volcanic arc is characterized byrelatively high Quaternary volcanic extrusion rates and hot-spring discharge rates, and by high conductive h at flow. However, a large area of near-zero near-surface onductive h at flow occurs in the younger volcanic rocks, due to downward and lateral flow of cold groundwater. Alternate models for the high heat flow...