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2015
In North-Hungary, east of the Danube the hilly regions and middle mountains mostly consist of Oligocene–Miocene geological formations. Among them the early Ottnangian rhyolite tuff (Gyulakeszi Rhyolite Tuff Formation) is very typical. The tuffs are mainly ignimbrites originated from episodes of intensive volcanic eruptions repeated two to four times ...
Zoltán Pintér +3 more
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In North-Hungary, east of the Danube the hilly regions and middle mountains mostly consist of Oligocene–Miocene geological formations. Among them the early Ottnangian rhyolite tuff (Gyulakeszi Rhyolite Tuff Formation) is very typical. The tuffs are mainly ignimbrites originated from episodes of intensive volcanic eruptions repeated two to four times ...
Zoltán Pintér +3 more
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Leaching behaviour and electrical conductivity of natural rhyolite and modified synthetic rhyolites
Chemical Geology, 1983This paper describes the leaching behaviour and electrical conductivity of natural rhyolite and three synthetic aluminosilicate glasses prepared by the addition of Na2O and CaO to the composition of natural rhyolite. Frequency-dependent a.c. conductivity measurements show that the conductivity is governed essentially by the Na+ mobility and that this ...
Alan R. Allnatt +8 more
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Gondwana Research, 2000
Abstract The late Proterozoic Malani bimodal volcanics constitute the largest suite of anorogenic acid volcanics in India. The volcanism took place during 745±10 Ma ago, succeeding the granitic activity of Abu pluton and ceased before the onset of Marwar sedimentation.
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Abstract The late Proterozoic Malani bimodal volcanics constitute the largest suite of anorogenic acid volcanics in India. The volcanism took place during 745±10 Ma ago, succeeding the granitic activity of Abu pluton and ceased before the onset of Marwar sedimentation.
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Diffusion of water in rhyolitic glasses
Geochimica et Cosmochimica Acta, 1991Water dehydration experiments on rhyolitic glasses have been carried out at 400-550 degrees C under a N2 atmosphere. Concentration profiles of both H2O molecules and OH groups were measured by Fourier transform infrared spectroscopy. As found in previous studies of water diffusion in rhyolitic melts, the measured total water concentration profiles do
Zhang, Youxue +2 more
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Hydration Rind Dates Rhyolite Flows
Science, 1968Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.
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A Paleoproterozoic A-type Rhyolite
Chinese Journal of Geochemistry, 1999The rhyolites in the upper Luliang Group of Shanxi, China, are Paleoproterozoic weakly alkaline volcanic rocks. They are characterized by high SiO2, Na2O + K2O, Zr, Nb, Ga, Y and REE contents and large FeO* /MgO, Rb/Sr and Ga/Al ratios, and low CaO, Sr and Eu contents, and share much in common with the A-type granitic rocks.
Yu Jinhai, Wang Dezi
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Layering in Yellowstone Rhyolite
The Journal of Geology, 1939The layered structure of much of the rhyolite of Yellowstone National Park consists of either a wavy lamination or a coarse stratification. Iddings attributed the layering to spreading of heterogeneous lava. Evidence is herein presented in favor of that hypothesis.
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Glauconitization of Rhyolite Sand Grains
SEPM Journal of Sedimentary Research, 1964ABSTRACT Rhyolite sand grains showing sequential replacement by glauconite have been observed in Upper Cambrian Lamotte-Bonneterre transitional beds near Ironton, Missouri. No evidence of direct organic action during replacement was observed, but it is possible that accumulated organic detritus contributed to the physico-chemical environment favorable ...
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