Geology of the central Mineral Mountains, Beaver County, Utah

Sibbett, B.S.; Nielson, Dennis L.

doi:10.2172/5040670

Cited by 13 publications

(13 citation statements)

References 4 publications

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“…A 26 MW electrical power plant 2 km from Opal Mound draws its fluids from three wells (Blackett and Ross, 1992). The geologic and geothermal characteristics of the area have been documented elsewhere (Armstrong, 1970;Park, 1971;Nielson and others, 1978;Ward and others, 1978;Parry and others, 1979;Bamford and others, 1980;Sibbett and Nielson, 1980;Capuano and Cole, 1982;Christensen and others, 1983;Moore and Nielson, 1994). Sinter occurs along the Opal Mound fault ( fig.…”

Section: Geothermal Settingsmentioning

confidence: 87%

Tracking crystallinity in siliceous hot-spring deposits

Lynne¹,

Campbell²,

James³

et al. 2007

American Journal of Science

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Siliceous hot spring deposits (sinters) entrap paleoenvironmentally significant components and are used as extreme-environment analogs in the search for early Earth and extraterrestrial life. However, sinters undergo a series of textural and mineralogical changes during diagenesis that can modify and overprint original environmental signals. For ancient hydrothermal settings including those close to the dawn of life, these transformations have long since occurred, so that study of diagenetic processes and effects is best undertaken in much younger deposits still undergoing change. Three young sinters preserve the entire diagenetic sequence of silica phases, from opal-A to quartz. The 6000 to ϳ 11,500 years BP ؎ 70 years sinter at Steamboat Springs, Nevada, the ϳ 1600 -1900 ؎ 160 years BP Opal Mound sinter at Roosevelt Hot Springs, Utah, and the ϳ 456 ؎ 35 years BP deposit at Sinter Island, Taupo Volcanic Zone, New Zealand, provide an opportunity to track crystallographic, mineralogic and morphologic transitions of sinter diagenesis using standard and new analytical approaches. Worldwide, sinter forms from cooling, alkali chloride waters as noncrystalline opal-A, transforming first into noncrystalline opal-A/CT, then paracrystalline opal-CT ؎ moganite, paracrystalline opal-C, and eventually to microcrystalline quartz. In this study, these changes were identified by the novel and combined application of electron backscatter diffraction, X-ray powder diffraction, and scanning electron and optical microscopy techniques. We show that mineralogical changes precede morphological and accompanied crystallographic transformations. During this modification, silica particles grow and shrink several times from the micron-to nano-meter scales via dissolution, reprecipitation and recrystallization, and diagenesis follows the Ostwald Step rule. All deposits followed nearly identical diagenetic pathways, with time as the only variable in the march toward physicochemically stable quartz crystals. Diagenesis alters original environmental signatures trapped within sinters. After five silica phase changes, filamentous microfossils are modified but still remain recognizable within sinter from the Opal Mound and Steamboat Springs deposits, and during the opal-A to opal-CT silica phase transformations at Sinter Island. Therefore, delineating diagenetic components and how they affect sinters is necessary to accurately identify biosignals from ancient hot-spring deposits.

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Section: Geothermal Settingsmentioning

confidence: 87%

Tracking crystallinity in siliceous hot-spring deposits

Lynne¹,

Campbell²,

James³

et al. 2007

American Journal of Science

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show abstract

“…The geothermal reservoir, which covers an area of approximately 32 km 2 , is developed in fractured Precambrian gneiss and Tertiary granite (Christensen et al, 1983;Ward et al, 1978;Moore and Nielson, 1994). Fluid circulation is controlled by high-angle normal faults trending northerly and easterly, and westward dipping, lowangle normal faults (Neilson et al, 1978;Sibbett and Nielson, 1980). Hydrothermal-alteration mineral assemblages of the reservoir host rocks were reported by Parry et al (1979) and Moore and Nielson (1994).…”

Section: Previous Studies and The Geologic Setting Of Roosevelt Hot Smentioning

confidence: 90%

Diagenesis of 1900-year-old siliceous sinter (opal-A to quartz) at Opal Mound, Roosevelt Hot Springs, Utah, U.S.A.

Lynne

Campbell

Moore

et al. 2005

Sedimentary Geology

136

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“…Springs KGRA, f o r example, massive T e r t i a r y g r a n i t i c rocks are believed t o be f a r superior as r e s e r v o i r hosts t o t h e f o l i a t e d Precambrian gneisses they i n t r u d e (Sibbett and Nielson, 1980), y e t t h e two rock types can be mistaken f o r one another i n d r i l l c u t t i n g s (Fig. 7).…”

Section: F F I C U L T T O I D E N T I F Y and D I F F E R E N T I A mentioning

confidence: 99%

Sampling and Interpretation of Drill Cuttings from Geothermal Wells

Hulen¹,

Sibbett²

1981

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Geology of the central Mineral Mountains, Beaver County, Utah

Cited by 13 publications

References 4 publications

Tracking crystallinity in siliceous hot-spring deposits

Tracking crystallinity in siliceous hot-spring deposits

Diagenesis of 1900-year-old siliceous sinter (opal-A to quartz) at Opal Mound, Roosevelt Hot Springs, Utah, U.S.A.

Sampling and Interpretation of Drill Cuttings from Geothermal Wells

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