 | Leavitt, E. D., Spell, T. L., Goldstrand, P. M., Arehart, G. B. (2004) Geochronology of the Midas Low-Sulfidation Epithermal Gold-Silver Deposit, Elko County, Nevada. Economic Geology, 99 (8) 1665-1686 doi:10.2113/gsecongeo.99.8.1665 | Journal (article/letter/editorial) | | were deposited on a relatively impermeable rhyolite flow. During this period, faulting and tilting of...Au-Ag mineralization is identical to the age of rhyolite intrusions whose source magma chamber likely provided...2 Ma. The temporal and spatial coincidence of rhyolite volcanism, faulting, and high-grade mineralization...the bulk of the ore contained within the Colorado Grande and Gold Crown veins. Exploration efforts in the...2001). They are most commonly associated with rhyolite flows and domes in extensional rift environments |  | | Report (issue) | | ~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 |  | | Journal (article/letter/editorial) | | tributaries Dunnerdale Beck and Long Mire Beck. The village of Upha lies in the Duddon valley between Seathwaite...1,550 550 1,100 There are minor intrusions of rhyolite and felsite. The maximum thickness of volcanic...district itself and the Ulpha Andesites from the village near which they crop out in strength. Duddon Bridge...top and bottom beds of the group show excellent flow-brecaation. Near Thwaite Yeat in the south-west...much altered and are mainly sericitic aggregates. Ilmenite occurs as an accessory mineral and the groundmass |  | | Report (issue) | | 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 |  | | Report (volume) | | L. Mosier 25h 162 166 Descriptive model of rhyolite-hosted Sn, by Bruce L. Reed, Wendell Duffield...Donald H. Richter 168 Grade and tonnage model rhyolite-hosted Sn, by Donald A. Singer and Dan L. Mosier...lithologic-tectonic environments to deposit models Flow sheet showing the evolution of model types 9 Schematic...Cartoon cross section of a rhyolite-hosted Sn deposit 170 Tonnages of rhyolite-hosted Sn deposits 171 Tin...Tin grades of rhyolite-hosted Sn deposits 171 Tonnages of volcanic-hosted magnetite deposits 173 Iron |  | | Journal (article/letter/editorial) | | interlayered shale and rhyolite extrusives of Middle Silurian age and (2) rhyolite and basalt extrusives...MEMBER Basalt and rhyolite flows; minor argillite 2200:^ UPPER RHYOLITE MEMBER Rhyolite flows and tuffs...2300 ± LOWER RHYOLITE MEMBER Basalt flows; minor rhyolite flow breccia, and scoria Rhyolite flows LOWER... en c/s 0 Tl faulting Hornfelsic shale and rhyolite QUODDY SHALE o C Absent in mapped area OAK...Brunswick. It was named from exposures at the village of Oak Bay, New Brunswick (Alcock, 1946a; 1946b) |  | | Report (issue) | | 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 |  | | Report (issue) | | .......................................... 10 Rhyolite ite intrusives .................................miles east of the Rio Grande, and lies 14 miles southeast of Domingo, a village on the Atchison, Topeka...pattern is radial and drains southeastward to the Rio Grande. CLIMATE AND VEGETATIO N The climate of the Cochiti...except for a few stretches fed by springs. They flow only during periods of melting snow or during summer...rhyolitic and andesitic flows. The Pleistocene rhyolite, which crops out at Bland, had as its source the |  | | Journal (issue) | | and field relationships of the Tardree Tertiary Rhyolite Complex, County Antrim, Northern Ireland, by R...PLATH 4. The Tardree Rhyolite Dome from Camearny Plantation Columnar rhyolite of Tardree Dome Fan-shaped...Fan-shaped arrangement of rhyolite columns Platy rhyolite of Scolboa Flow Welded rhyolitic tuff with eutaxitic...in Northern Ireland .. Geology of the Tardree Rhyolite Complex Plan of the Sandy Braes vent .. Section...the opaque oxide is magnetite with subordinate ilmenite. This particular specimen also contains an interstitial |  | | Journal (article/letter/editorial) | | is compared with the commonly applied magnetite–ilmenite (mgt–ilm) oxybarometer of Ghiorso and Evans (2008)...vanadium (Dmgt/melt V analyzing magnetite and ilmenite phenocrysts and the surrounding, glassy matrix...Lordsburg mgt, ilm, zirc, ap rhyolite Lordsburg granodiorite Smelter Knolls rhyolite Banco Bonito vitrophyre... – 940 ± 140 (mp) 0.8 ± 0.4 (mp) Glass Creek Flow vitrophyre qtz, plag, Kfsp, mgt, Glassy ilm, ap...apatite, bio biotite, fl fluorite, fsp feldspar, ilm ilmenite, Kfsp potassic feldspar, mgt magnetite, mon monazite |  | | Journal (article/letter/editorial) | | 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 |  | | Journal (article/letter/editorial) | | Yarlside to Shap Fells. Northwards from this line flow a series of streams which eventually unite to form...Scale (approximate) 4 Troutbeck, through the village itself, although here it is shifted by a considerable...Troutbeck and Kentmere, and thence through Kentmere village and over Stile End into Long Sleddale. This depression...500 itie. Froswick Tufts. Lithic tufts and rhyolite-flow. 200 Nan BieldAndesites. Lava-flows, with thin...maximum thickness of 3700 feet. Intrusions of rhyolite, quartz-porphyry, lamprophyre, andesite, spilite |  | | Book | | landscapes and geomorphology, lava v vi Foreword flow structures related to emplacement and solidification...University, Nagpur, India e-mail: dinomohabey@yahoo.com Lucia Castanheira de Moraes CEFET-MG—Centro Federal de...landscapes (Chap. 2), lava flow morphology and stacking patterns (Chap. 3), lava flow structures (Chaps. 4...by extensive ferricrete (laterite), to reach the hill town of Mahabaleshwar (1436 m) on the top. More...Basalt flows. The capping, cliff-forming, black flow is up to about 80 m thick and is tachylitic. More |  | | Report (issue) | | ........................................ . 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 |  | | Journal (article/letter/editorial) | | 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 |  | Scott, Robert B., Harding, Anne E., Swadley, W.C., Novak, Steven W., Pampeyan, Earl H. (1991) Preliminary geologic map of the Vigo NW Quadrangle, Lincoln County, Nevada. Open-File Report Vol. 1991 (91-389) US Geological Survey doi:10.3133/ofr91389 | Report (issue) | | boulders as much as 1.5 m across. Clasts consist of ash-flow tuff and lava; clasts of vesicular basalt are locally...boulders, commonly less than 1 m in diameter, of ash-flow tuff and lava. Unit forms small poorly exposed,...to rounded pebbles, cobbles, and boulders of ash-flow tuff and lava as much as 1.5 m in diameter. Sand...subrounded pebbles, cobbles, and boulders of ash-flow tuff and lava; includes abundant boulders 0.6 to...slopes developed on Tertiary basalt and rhyolitic ash-flow tuff. Unit thickness undetermined Ta Alluvium |  | | Journal (article/letter/editorial) | | the Tweed Volcano is: Beechmont Basalt (base)—Rhyolite (composed of two distinct units, the Springbrook...sanidine, ilmenite, ferrohypersthene (Springbrook rhyolite), and quartz, sanidine, oligoclase, ilmenite, rare...extremely ulvospinel-rich titanomagnetite (Binna Burra rhyolite). Phenocryst equilibration temperatures are estimated...°C for the Springbrook rhyolite and ~ 800-950 °C for the Binna Burra rhyolite, at oxygen fugacities in...quartz, fluor-arfvedsonite, minor acmite, and ilmenite. Pb isotopic compositions indicate at least two |  | | Book | | historian-collector William J. Brunet set out to trace three ilmenite occurrences mentioned in late 19th-century literature...ridge had once been mined for quartz, and large ilmenite masses could be seen on the old dumps. In 1975-1976...Brunet collected sharp, black, flattened hexagonal ilmenite crystals to 7 .5 cm in matrix of massive quartz...judgment, many more "lost" localities for good ilmenite crystals exist in the region (Brunet, I 977b )...Amity-Edenville entry for Edenite and Spine!). Ilmenite is not common in the metasedimentary rocks of |  | | Journal (article/letter/editorial) | | lookssomething like an excessivelysilicifiedporphyritic rhyolite with the phenoca:ysts of orthoclaseintact. For...the southwestslopeof Balloon Hill. BalloonHill is cappedby a rhyolite flow and surroundedon its lower flanks...flanks by a silicified rhyolite tuff or dacite tuff. The materialdescribed occursas a singlenarrow...sometimesbandedwhite and gray or has a very fine textnre. The rhyolite cappingBalloonHill is a light grayishporphyrkic...secondaryquartz. Secondaryquartz is also prominent in the rhyolite and one specimen(No. 2t from Balloon-Mascotle |  | | Report (issue) | | Geological Surveyor, reported on a gold-bearing rhyolite at , (irassy Gully. § {5.) (6.) Mr. W. H. J...reefs are- contained in an old rhyolite, which exhibits traces of flow structure.f The rough and mountainous...Matsoa in 1887, under the sandstone capping of the hill, and 350 feet above the level of the creek. The...the hill in 1891. In 1901 the tunnel was carried a further 100 feet. The idea was to test the hill, and...extend in a north and south direction through a rhyolite flow, and the country was rapidly taken up over a |  | | Book (volume) | | river to include AI) ⎯agate. GALVA, N, at Bishop Hill, area⎯agate, jasper. JEFFERSON COUNTY MT. VERNON...Co.) ⎯Hematite, Magnetite, placer Gold, Pyrite, Ilmenite, Corundum, Garnet, Diamond, Zircon. (Diamonds...good quality material, especially along the Smoky Hill River in Gove, Logan, Trego, and Wallace counties...mi., in Cretaceous outcrops (banks) of the Smoky Hill R., in lignite beds⎯Amber. The old collection area...LOGAN COUNTY ELKADER, up and downstream of the Smoky Hill R., weathered out of chalk bluffs⎯moss agate. McPHERSON |  | | Book (volume) | | river to include AI) ⎯agate. GALVA, N, at Bishop Hill, area⎯agate, jasper. JEFFERSON COUNTY MT. VERNON...Co.) ⎯Hematite, Magnetite, placer Gold, Pyrite, Ilmenite, Corundum, Garnet, Diamond, Zircon. (Diamonds...good quality material, especially along the Smoky Hill River in Gove, Logan, Trego, and Wallace counties...mi., in Cretaceous outcrops (banks) of the Smoky Hill R., in lignite beds⎯Amber. The old collection area...LOGAN COUNTY ELKADER, up and downstream of the Smoky Hill R., weathered out of chalk bluffs⎯moss agate. McPHERSON |  | | Report (issue) | | Basalt, 31. Ophite, 31. Porphyrite, 31. Rhyolite, 3~. Flow Units, 33. Interflow Sediments, 34. Crevice...of the Puckwunge formation ...... 29 15. Five flow units at Sugarloaf Point, Lake Superior ..........GEOLOGY OF COOK COUNTY smaller percentage of rhyolite. The oldest flows crop out near Grand Portage...Coastal Hills. The larger rivers of this division flow mostly in courses transverse to the major ridges...FIGURE 7 . - 9 Grand Marais Ha rbor, sawtooth hill s in th e background . (Co urtesy Hamilton Photo |  | | Report (issue) | | .............. 6 Rhyolite................................... Rhyolitic ash-flow tuff....................................................... 12 Rhyolite flow and rhyolitic tuff..................... 12 Basalt...alkali-feldspar granite. Two small outcrops of Tertiary rhyolite are present in the quadrangle. The predominant...rhyolitic tuff near the southeastern corner and rhyolite in the north-central part of the quadrangle. Unconsol...subaerial explosive eruptions and deposition of ash-flow and ash-fall tuff. Rocks in the western part of |  | | Journal (article/letter/editorial) | | Abstract. Basaltic lava flows and high-silica rhyolite domes form the Pleistocene part of the Coso volcanic...< 5 0 % SiO2) were erupted well away from the rhyolite field at any given time. Compositional variation...containing up to 58% SiO2, erupted adjacent to the rhyolite field, formed by mixing of basaltic and silicic...erupted near the Sierra Nevada fault zone. Several rhyolite domes in the Coso volcanic field contain sparse...commingling and local diffusive mixing of andesite and rhyolite at contacts, concentric vesicle distribution, |
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