Ash-flow tuffs: Their origin, geologic relations, and identification

Ross, Clarence S.; Smith, Robert L.

doi:10.3133/pp366

Cited by 275 publications

(233 citation statements)

References 19 publications

(30 reference statements)

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“…Vapor-phase formation of tridymite (along with sanidine and iron oxides) occurs in vugs and lithophysae in rhyolitic ash-flow tuff (28)(29)(30)(31)(32)(33)(34)(35). For example, the mineral stratigraphy within compound cooling units of a rhyolitic ash-flow tuff showed tridymite is most abundant (∼25 wt.%) in the central zone where temperatures were highest and occurs along with sanidine as crystals growing into voids; cristobalite and sanidine occur in cooler zones where replacement of glass predominates (30).…”

Section: Tridymite Formation Pathwaysmentioning

confidence: 99%

Silicic volcanism on Mars evidenced by tridymite in high-SiO ₂ sedimentary rock at Gale crater

Morris

Vaniman

Blake

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

187

230

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Tridymite, a low-pressure, high-temperature (>870°C) SiO 2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity. The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition with ∼74 wt.% SiO 2 (Alpha Particle X-Ray Spectrometer analysis). Plagioclase (∼17 wt.% of bulk sample), tridymite (∼14 wt.%), sanidine (∼3 wt.%), cation-deficient magnetite (∼3 wt.%), cristobalite (∼2 wt.%), and anhydrite (∼1 wt.%) are the mudstone crystalline minerals. Amorphous material is silica-rich (∼39 wt.% opal-A and/or high-SiO 2 glass and opal-CT), volatile-bearing (16 wt.% mixed cation sulfates, phosphates, and chlorides−perchlorates−chlorates), and has minor TiO 2 and Fe 2 O 3 T oxides (∼5 wt.%). Rietveld refinement yielded a monoclinic structural model for a well-crystalline tridymite, consistent with high formation temperatures. Terrestrial tridymite is commonly associated with silicic volcanism, and detritus from such volcanism in a "Lake Gale" catchment environment can account for Buckskin's tridymite, cristobalite, feldspar, and any residual high-SiO 2 glass. These cogenetic detrital phases are possibly sourced from the Gale crater wall/rim/central peak. Opaline silica could form during diagenesis from high-SiO 2 glass, as amorphous precipitated silica, or as a residue of acidic leaching in the sediment source region or at Marias Pass. The amorphous mixed-cation salts and oxides and possibly the crystalline magnetite (otherwise detrital) are primary precipitates and/ or their diagenesis products derived from multiple infiltrations of aqueous solutions having variable compositions, temperatures, and acidities. Anhydrite is post lithification fracture/vein fill.Mars | tridymite | Gale crater | lake | volcanism T he Mars Science Laboratory (MSL) rover, Curiosity, has been exploring sedimentary rocks within Gale crater since landing in August 2012, and progressing upward through a sequence of strata exposed along the lower slopes of Aeolis Mons (informally known as Mount Sharp). This traverse has taken Curiosity through sequences of fluvial, deltaic, and lacustrine sediments (e.g., ref. 1). On sol 1057 (the number of martian days since landing), Curiosity began preparations for collecting drill powder from high-silica sedimentary rock at a location named Buckskin. We describe the geologic setting of the Buckskin sample location, the detection of significant amounts of the silica polymorph tridymite by the MSL Chemistry and Mineralogy (CheMin) X-ray diffraction instrument, and its implications for volcanism on Mars. Geologic SettingThe Buckskin outcrop is part of the Murray formation of lacustrine mudstones exposed in the Marias Pass area (SI Appendix, Figs. S1 and S2). The formation was previously studied in the Pahrump Hills (Fig. 1A). Here the laminae have a mean thickness of ∼0.5 mm and are characteristical...

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Section: Tridymite Formation Pathwaysmentioning

confidence: 99%

Silicic volcanism on Mars evidenced by tridymite in high-SiO ₂ sedimentary rock at Gale crater

Morris

Vaniman

Blake

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

187

230

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“…Tridymite occurs in vesicles of some spherulitic rhyolites and presumably forms even later than cristobalite, probably by vapour phase deposition in the same way that Ross and Smith (1961) regard the mineral as having formed in ignimbrites. The amount of tridymite is small, but incl1eases if the rhyolites are heated (e.g., by inclusion in the basalt of the 1886 eruption), so that it may also form by pneumatolytic metasomatism after solidification, as suggested by Rogers (1928).…”

Section: Tridymitementioning

confidence: 99%

Petrography of the rhyolite lavas of Tarawera Volcanic Complex

Cole

1970

New Zealand Journal of Geology and Geophysics

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903The rhyolite domes and associated lava flows of the Tarawera Volcanic Complex, North Island, New Zealand, can be divided into four rock types: hypersthenehornblende rhyolite; hornblende-biotite-rhyolite; hypersthene rhyolite, and biotite rhyolite.Two types of biotite are found within the lavas; "normal" biotite with a y refractive index of 1· 65-1' 67 and "ferrian" biotite with a y refractive index of 1· 72-1' 74. Four types of hornblende occur: a pale one (similar to cummingtonite), and green, brown, and basaltic ones. The concentration of KzO in the lava was probably the controlling factor which determined whether biotite or hornblende (or both) crystallised. Plagioclase occurs in all lavas, and quartz in most. Where they both occur initial crystallisation appears almost synchronous and subsequent resorption was probably due to variations in water pressure within the magma reservoir.

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“…The liva Canyon Member of the Paintbrush Tuff is a laterally continuous (Byers and others, 1976), compositionally zoned, compound-cooling unit (Ross and Smith, 1961) and accounts for most of the outcrop in the Yucca Mountain area. The Yucca Mountain and Pah Canyon members of the Paintbrush Tuff are small-volume, simple-cooling unit ash-flow tuffs (Byers and others, 1976).…”

Section: Geologic and Hydrologic Settingmentioning

confidence: 99%

Revised potentiometric-surface map, Yucca Mountain and vicinity, Nevada

1993

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Ash-flow tuffs: Their origin, geologic relations, and identification

Cited by 275 publications

References 19 publications

Silicic volcanism on Mars evidenced by tridymite in high-SiO ₂ sedimentary rock at Gale crater

Silicic volcanism on Mars evidenced by tridymite in high-SiO ₂ sedimentary rock at Gale crater

Petrography of the rhyolite lavas of Tarawera Volcanic Complex

Revised potentiometric-surface map, Yucca Mountain and vicinity, Nevada

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Ash-flow tuffs: Their origin, geologic relations, and identification

Cited by 275 publications

References 19 publications

Silicic volcanism on Mars evidenced by tridymite in high-SiO 2 sedimentary rock at Gale crater

Silicic volcanism on Mars evidenced by tridymite in high-SiO 2 sedimentary rock at Gale crater

Petrography of the rhyolite lavas of Tarawera Volcanic Complex

Revised potentiometric-surface map, Yucca Mountain and vicinity, Nevada

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Silicic volcanism on Mars evidenced by tridymite in high-SiO ₂ sedimentary rock at Gale crater

Silicic volcanism on Mars evidenced by tridymite in high-SiO ₂ sedimentary rock at Gale crater