Pleistocene to present evaporitic lacustrine sediments in Lake Magadi, East African Rift Valley, Kenya were studied and mapped using spectral remote sensing methods. This approach incorporated surface mineral mapping using space-borne hyperspectral Hyperion imagery together with laboratory analysis, including visible, near-infrared diffuse reflectance spectroscopy (VNIR) measurements and X-ray ...

Kahang Cu Porphyry deposit is situated in the central part of a major Iranian magmatic belt, Urumieh-Dokhtar, in central Iran.There are several sub-volcanic stocks (e.g., porphyric granitoids rocks, quartz monzonite, diorite and monzodiorite-monzogranite)within Eocene volcanic and pyroclastic rocks consisting of basaltic, trachy-andesite and dacitic rocks. Hydrothermal alterations at the Kahang...

The Isua greenstone belt (Fig. 1) contains the oldest known, relatively well preserved, metavolcanic and metasedimentary rocks on Earth. The rocks are all deformed and many were substantially altered by metasomatism, but both the deformation and metasomatism were heterogeneous. Transitional stages can be seen from relatively well preserved primary volcanic and sedimentary structures to schists ...

Polar ice core records attest to a colossal volcanic eruption that took place ca. A.D. 1257 or 1258, most probably in the tropics. Estimates based on sulfate deposition in these records suggest that it yielded the largest volcanic sulfur release to the stratosphere of the past 7,000 y. Tree rings, medieval chronicles, and computational models corroborate the expected worldwide atmospheric and c...

Multicondition-driven mechanisms may produce pyroclastic deposits varying in fundamental properties such as dispersal, grain size, vesicularity and morphology of juvenile clasts, and the abundance of lithic or ‘‘wall rock’’ ejecta (xenoliths). Volcanic ash particles from different fragmentation mechanisms have different surface textures and morphologies. The analysis of the volcanic clast shape...

The volcanic island of Surtsey (Vestmannaeyjar, Iceland) is the product of a 3.5-year-long eruption that began in November 1963. Observations of magma-water interaction during pyroclastic episodes made Surtsey the type example of shallow-to-emergent phreatomagmatic eruptions. Here, in part to mark the 50(th) anniversary of this canonical eruption, we present previously unpublished major-element...

Abstract Apatite is a powerful research tool because it common in various rocks and incorporates many chemical elements. Understanding how elements partition between apatite melt the controls on are critical for applications of apatite. It has been recently proposed that MgO content magmatic proportional to melt, highlighting potential importance this oxide as parameter. A comprehensive compila...