Bentonite deposits of economic interest are widespread in Tashtab Mountains (Khur), east of Isfahan province, Iran. Several bentonite deposits have been developed in this area as a result of Eocene volcanic alteration. These deposits are classified as Khur bentonite horizon. XRD analyses reveal that alteration products consist of Na-montmorillonite, kaolinite, quartz, calcite, and crystobalite....

Introduction: Water liquid has been considered to be main fluid in cold Mars, though major sources of liquid water are not clearly found on Martian surfaces. Recently author (Y.M.) found carbon-bearing grains on plagioclase composition in druses of terrestrial volcanic basalts in Shimonoseki, Yamaguchi, Japan [1], where many scientists have been reported as normal “plagioclases” formed at hydro...

Volcanic eruptions and lava flows comprise one of the most highly stressed terrestrial environments for the survival of biological organisms; the destruction of botanical and biological colonies by molten lava, pyroclastic flows, lahars, poisonous gas emissions and the deposition of highly toxic materials from fumaroles is the normal expectation from such events. However, the role of lichens an...

Wrangellia Superterrane. The Paleozoic to Mesozoic Wrangellia superterrane (Insular terrane) consists of intraoceanic volcanic assemblages and basement rocks of the Peninsular, Wrangellia, and Alexander terranes (Plafker et al, 1994). The magmatic-arc assemblages of the Peninsular terrane appear to have been built upon the Wrangellia composite terrane prior to the midCretaceous and include: 1) ...

by intermittent land masses on the northeast and southwest. The area has been cut by numerous right-lateral transcurrent faults and the stratified rocks now lie along the northeastern flank of the Coast Plutonic Complex. leletzky and Tipper (1968) described a faunal stratigraphy for the Taseko Lakes map sheet and discussed the role of the Qaughton trough in the geological history of southwester...

Bimodal volcanism in the Santa Maria Province of west-central California occurred when segments of the East Pacific Rise interacted with a subduction zone along the California margin during the Early Miocene (about 17 million years ago). Isotopic compositions of neodymium and strontium as well as trace-element data indicate that these volcanic rocks were derived from a depleted-mantle (mid-ocea...

Negative carbon isotope anomalies in carbonate rocks bracketing Neoproterozoic glacial deposits in Namibia, combined with estimates of thermal subsidence history, suggest that biological productivity in the surface ocean collapsed for millions of years. This collapse can be explained by a global glaciation (that is, a snowball Earth), which ended abruptly when subaerial volcanic outgassing rais...

The end-Permian extinction is typically ascribed to massive volcanic eruptions, but direct geochemical evidence linking the two independent events is generally lacking. Zinc is an important micronutrient of marine phytoplanktons, and Zn isotope (d66Zn) ratios of seawater are markedly higher than those of volcanic rocks and riverine waters. We conducted high-resolution Zn concentration and Zn is...