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| Plain–Yellowstone Region and Adjacent Areas The Littlefield Rhyolite and associated mafic lavas: Bimodal volcanism...province, with constraints on age and storage sites of Grande Ronde Basalt magmas Brian M. Webb1, Martin J. Streck1...Health Sciences, Eastern Oregon University, La Grande, Oregon 97850, USA 1 CITATION: Webb, B.M., Streck... W.C., and Ferns, M.L., 2019, The Littlefield Rhyolite and associated mafic lavas: Bimodal volcanism...province, with constraints on age and storage sites of Grande Ronde Basalt magmas: Geosphere, v. 15, no. 1, p |
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| mudflow deposit, and flow ____________________________________ _ Rhyolitic ash-flow tuff ______________________...and Lloyd shaft ____ --_-----_Manganese Hill and Chimney Hill mines_Last Chance mine _________________...fluorspar mine. Geologic maps of the Manganese Hill and Chimney Hill fluorspar deposits. Geologic maps and vertical...semiquantitative spectrographic analyses, gray rhyolite flow, Ruby Mountain, Chaffee County_ Sample data...surface is a pediment of late flow deposit, and a rhyodacite porphyry flow of Eocene ( ?) age Tertiary |
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| ................. Red Rock by metamorphism of rhyolite.................................................in oxides from base of the Endion sill to the rhyolite above........... 1147 5. Diagram of normative...sill to the rhyolite above....... 1158 8. Relative amounts of albite, orthoclase, and anorthite molecules...Variation diagrams of the Duluth sills and overlying rhyolite flows................ 1167 11. Alkali-silica ratios...intrusive into flows of Keweenawan basalt and rhyolite. Three of the sills are large, and each consists |
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| the caldera. (See photographic point. pl. 1). Rio Grande has cut its va lley in soft lacustrine deposits...______________ --- __ ----- _------ - ---Bachelor Mountain Rhyolite ____ -- __ -_-- __ -----_-_--Distribution and...eutaxitic and fluidal structures_______ Farmers Creek Rhyolite ____________ - _-- __ -------- -- Distribution...composition ________________ -____ Mammoth Mountain Rhyolite _______________ -_-_---__ Source_____________..._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Ash flow boundaries and partings_________________ Characteristics |
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| mafic and felsic dykes. The terrestrial basalt-rhyolite/trachyte volcanism of Malani is characterised................................... Peralkaline rhyolite . . ........................................................................ Peraluminous rhyolite . ............. ........ . ................voluminous acid flows, which culminated with ash flow deposits. The second phase experienced intrusion...voluminous outpouring of peralkaline and peraluminous rhyolite, rhyodacite and trachyte flows during the second |
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| voluminous outpouring of peralkaline and peraluminous rhyolite, basalt, dacite and trachyte flows. The third...third stage ceased with the outburst of ash flow deposits. The dominant felsic volcanics are rhyolites and...31,000 km2.The other rock types associated with rhyolite are trachytes, dacites, pitchstone, welded tuff...vogue. Areal Extent The MIS occurs as residual hill tors, inselbergs and scattered hummocks over 5...fragments of basement granite embedded in overlying rhyolite. Fig. 2B. Pentagonal and hexagonal columnar jointing |
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| ~7 11. Flow banding in ferro granodiorite .......................... 34 12. Basalt flow inclusions...preliminary papers (Taylor, 1956; Goldich, Taylor, and Lucia, 1956). A brief summary is also given in Bulletin...assistance in the field was given in 1953 by F. J. Lucia and in 1954 by H. M. Gehman, Jr. The project was...and sericite. The black slate has well-developed flow cleavage and is composed largely of sericite and...sandstone or quartzite overlain by a Keweenawan lava flow. According to Schwartz (1949, p. 22) the conglomerate |
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| . . . . . . 71 Influence of Lava Flows on Fluid Flow . . . . . . . . . . . . . . . . . . . . . . . ....joints and fractures along which hydrothermal fluids flow. Active deformation of the Yellowstone caldera,...faulting and moderate local seismicity, high heat flow, rapid changes in climate, and regional stresses...system developed. Ascending hydrothermal fluids flow along fractures that have developed in response...basin of Yellowstone Lake, an area of high heat flow and active deformation within the Yellowstone caldera |
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| Lake: left – looking north to high hills of rhyolite and rhyolite breccia of the Thlewycho east lava dome...lower left: Blocky-jointed cliffs of flat-lying ash-flow tuff units of Innerring sequence, about 7 km northeast...Lambert. GSC 2005-040 lower right: White-weathering rhyolite derived turbidite beds on northern end of the...distribution Lithology Andesite and basalt Dacite Rhyolite Volcaniclastic and iron-rich sedimentary rocks...relations Stratigraphy Flow units Andesite lavas Dacitic lavas and tuffs Rhyolite lavas, domes, and intrusions |
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| resistance of the structure to volumetric and shear flow, respectively. The shear viscosity can be measured...references in Richet (1984) for (SiO2, ABalbite, AN-anorthite, DI-diopside): Astin (1962: 710-soda lime SRM...calculated using the method of Shaw (1972: R1A rhyolite). Other sources of data relating to relaxation...well-investigated silicate melts. These include SiO2, albite, anorthite, diopside, Na2SizO5, and NBS standard soda-lime...of interest is that of Spera et al. (1988) on rhyolite composition melts. Their study was performed with |
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| rock types V/eathering and outcrops willow Creek rhyolite General character and distribution ............Petrography Megascopic -.iicroscop 1 _ 1 rhyolite. General character and distribution. Contacts...Microscopic Weathering and outcrops Windy gulch rhyolite breccia General character and distribution Petrography...Comparison with Campbell Mountain rhyolite Hazanoth Mountain rhyolite General character and distribution...outcrops Comparison with the Campbell Mountain rhyolite Hhyolite tuff General character and distribution |
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| Calvados, and Orne. Their typical development is at Saint La, about twenty miles inland, almost due east of...erosion of both sedimentary and intrusive rocks. The Saint La shales are green and satin-like. The Jersey shales...beds than any other variety of the Phyllades de Saint Lo. TH E GEO LO GY OF JE RSEY . 153 They occupy...suggests pri ority t o the shale movement of the flow of t he eruptive rocks. At " Sally Mit chell 's...is loose matter with rhyolite blocks and andesite rubble. There is much rhyolite-debris and it is probably |
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| in Idaho: Physical and Chemical Characteristics, Flow Distribution, and Tectonic Implications. by V. E.... . . . . . . . . . . 55 Srratigraphy of rhe Grande Ronde Basalt, Columbia River Basalt Group, From... .. .. .. . . . . . . . . . . . .. . . . . . Rhyolite Lava Flows in the Bruneau-Jarbidge Eruptive Center...Stratigraphic Framework of the Pliocene and Miocene Rhyolite, Eastern Snake River Plain, Idaho, by G. F. Embree...cauldron complex with an eruption of rhyodacite ash-flow tuff, and it continued intermittently until about |
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| and weight-percent norms for selected samples of rhyolite and basalt from Buckskin Basin and Stevens Peak...fanglomerate, gravels, tuffaceous sandstones, ash-flow tuffs, rhyolitic flows, and freshwater limestone...in the lower member-the rhyolite of Two-and-a-Half-Mile Creek and the rhyolite of Stevens Peak-have potassium-argon...contains gravel, air-fall ash, and one olivine basalt flow dated at 7.0 million years. The top of the Starlight...changed markedly from predominantly rhyolitic ash-flow eruptions to olivine tholeiitic basalt flows (the |
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| (rhyodacite to dacite in composition) in the Ward and Gold Hill 7.5 minute quadrangles, Boulder County (Gable and...time ago by Williams and Curtis (1977) in a rhyolite flow at Sutter Buttes, California. The Colorado example...they impinged on plagioclase phenocrysts during flow of the magma. Small amounts of the interior of many...less silicic igneous rocks (greater normative anorthite) and in tonalites of deep-seated crystallization...The content of F is small (cf., phenocrysts in rhyolite analyzed by Schleicher and Lippolt 1981) and consistent |
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| A semi-quantitative model for fractionation of rhyolite from rhyodacite in a compositionally altered Archean...A semi-quantitative model for fractionation of rhyolite from rhyodacite in a compositionally altered Archean...subvolcanic and pyroclastic rhyodacite, subordinate rhyolite pyroclastic rocks and lava flows, minor intercalated...that is coeval with the felsic volcanic rocks. Rhyolite in PDLC differs from the associated rhyodacite...calculations using estimates of rhyodacite and rhyolite primary phenocryst compositions and estimates |
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| Gravel and silt member___________________________ Rhyolite member..........................................---------------------------------------------------·-Rhyolite intrusives of the northern Santa Rita Mountains...____ __ ___ Photomicrograph of vitrophyre from a flow in the rhyodacite member of the Grosvenor Hills...--25. Map showing the distribution of Oligocene rhyolite intrusives of the northern Santa Rita Mountains...Tuffaceous sandstone and overlying massive nearly white rhyolite tuff beds intercalated in the lower part of the |
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| ......................... Magnitude of the rhyolite flow........................................................ Basalt xenoliths wholly enclosed in rhyolite............................................................................... Pseudo-dike of rhyolite............................................................ Incipient alteration of basalt by rhyolite...................................................................... Complexes of basalt and rhyolite.............................................. |
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| Rio Grande from north of Weminuche meadows, San Cristobal quadrangle. The upper cliff-forming flow is...is Piedra rhyolite; the lower talus-covered slopes are underlain by Huerto quartz latite and Alboroto rhyolite...rhyolite. Geology and Petrology of the San Juan Region Southwestern Colorado By ESPER S. LARSEN, JR...granite. _____________________ Granite of the Rio Grande Canyon, in the western part of the San Cristobal...diorite---------------The Iron Hill complex.. _____________________ Marble of Iron Hill. ____________________ |
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| ........................................ . 25 Rhyolite and Felsite Flows ............................... . . . . . . . . . . . . . . S. Much-Jointed Rhyolite, Little Palisades, Lake Superior. . . . . . ....Typical Shore Line of Beaver Bay Diabase. Anorthosite Hill on the Sky Line...................................Flows below Rhyolite of the Palisades, Lake Superior 11. Columnar Jointing in a Thick Flow of Basalt,...Amygdules at the Basal Contact of a Flow, Sho'wing Direction of Flow. Shore of Lake Superior, Little Marais |
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| Garita Quartz Latite ________________________ _ Rhyolite of Miners Creek _______________________ _ Shallow...____________________ _ Bachelor Mountain Rhyolite ____________________ _ Farmers Creek Rhyolite ________________________...__ _ Mammoth Mountain Rhyolite ___________________ _ Rhyolite neck and flow near Shallow Creek _______..._______ _ Wason Park Rhyolite __________ ---- ____________ _ Huerto Formation ______________________________...deposits in the Creede Formation _______ -----Monon Hill mine ____________________ --- __ -----Solomon-Holy |
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| Publications Division - Illl III II IIIII Hill Hill Hill illii inn inn mil "« ""' '" ' '" '"" Frocns...tuff member : Porphyritic lava flows Gray Hills Rhyolite Member Upper gray tuff member INTRACALDERA FACIES...tuff member Blue Lake Rhyolite Member Middle tuff member Mount Baldy Rhyolite Member and volcanic breccia...Member. These rocks and associated rhyolitic ash-flow tuffs, lava flows, and volcanic breccias form the...intermediate-composition volcanos about 23 m.y. ago, and ash-flow tuffs from local and distant sources interleave |
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| .................................. Low-silica rhyolite............................................. Basalt.............................................. Ash-flow tuffs and potassium metasomatism..................Mesa............................ Analyses of ash-flow tuff..................................... Delayed...by a gravity low near the volcano. A 25-m.y. ash-flow tuff in the Harcuvar Mountains, 30 km south of McLendon...Th, and Rb/Sr ratios, is suggestive that the ash-flow tuff is genetically related to McLendon volcano |
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| magma chamber, buffering the magmas' compokm3 of rhyolite. The rhyolitic phase marked a 10 fold decrease...1981; silicic magmas immediately before eruption. Rhyolite production Oskarsson et al., 1982; Marsh et al...Rhyolites by Crystal Fractionation: the Basalt-Rhyolite Association at Volcan Alcedo, Galapagos Archipelago...that it is the only one that has erupted abundant rhyolite, although the volcano been attributed to different...crystal fractionation models of oceanic basalt-rhyolite associations need to be reassessed. The origin |
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| rocks range in composition from basalt through rhyolite, and the sedimentary rocks represent first cycle...include both submarine and subaerial, consisting of flow breccias and massive, columnar and pillowed lava...basalt, basaltic andesite, andesite, dacite, and rhyolite. The intrusive rocks include gabbro, basalt, basaltic...feldspar, as a groundmass phase, is found only in rhyolite and basaltic andesite. Apatite is an accessory...Amphibole Basalt Basaltic Andesite Andes ite Dacite Rhyolite Rock Type Phenocrysts OrthoClinoFe-Ti pyroxene |
