scholarly journals Silica Sinter and the Evolution of Hot Springs in the Alvord/Pueblo Valleys, Southeast Oregon, USA

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7186
Author(s):  
Leslie Allen Mowbray ◽  
Michael L. Cummings
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Late Pleistocene ◽  
Hot Springs ◽  
Basin And Range ◽  
Hydrothermal Systems ◽  
Water Levels ◽  
The Holocene ◽  
Crustal Thinning ◽  
Spring Area

Hot springs in the Alvord/Pueblo valleys in southeastern Oregon are analogous to Basin-and-Range hydrothermal systems where heat source and permeable pathways are met through crustal thinning. Silica sinter deposition at Mickey Springs, Alvord Valley, predates the late Pleistocene high stand of pluvial Lake Alvord. At Borax Lake, Pueblo Valley, sinter deposition occurred during the Holocene. This study examines the evolution of springs at Mickey Springs, where three morphologies of sinter are present: (1) basalt clasts surrounded by sinter in interbedded conglomerate and sandstone, (2) pool-edge and aprons of sinter surrounding depressions (12–32 m diameter), and (3) quaquaversal sinter mounds with pool-edge sinter. The oldest sinter occurs in silica-cemented conglomerate and sandstone, where deposition occurred prior to 30 kya. Deposition around broad depressions and mounds occurred after 30 kya but before water levels began to rise in pluvial Lake Alvord. Thermoluminescence dates suggest sinter deposition ceased before 18 kya when silt and clay filled inactive vents and buried aprons. A few mounds hosted active springs after sinter deposition ceased but while submerged in pluvial Lake Alvord. Now, high-temperature springs, steam vents, and mud pots are concentrated in a 50 × 50 m area near the southern edge of the spring area.

scholarly journals INTERPRETATION OF ALTERATION MINERALS AROUND THE OMA-HARUKU HOT SPRINGS, CENTRAL OF MOLUCCAS

2019 ◽  
Vol 2 (2) ◽  
pp. 090-096
Author(s):  
Helda Andayany ◽  
Josephus Ronny Kelibulin
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Hot Springs ◽  
Hot Spring ◽  
Geothermal Field ◽  
Petrographic Analysis ◽  
Rock Samples ◽  
Spring Area ◽  
Alteration Minerals ◽  
Xrd Method

Petrographic analysis to rock samples located at Oma-Haruku hot springs was dominated by mudstone. Another alteration mineral types of the rocks in this area are quartz, aragonite/calcite and feldspar minerals. Petrographic analysis was supported by the XRD method. The method indicated that the alteration minerals content was generally dominated by the presence of aragonite/calcite with particle size of 0.05 - 2 mm, the abundance of 55% and the spread evenly. Based on such presence of aragonite/calcite, one can interpret that the origin rock was carbonate. Alteration minerals which were generally dominated by mudstone indicate that the type of hot spring area in Oma-Haruku is a type of high-temperature reservoir, namely > 175 oC. Therefore, the area is  potentially as geothermal field in Central of Moluccas.

Microstructure of high-temperature (>73 °C) siliceous sinter deposited around hot springs and geysers, Yellowstone National Park: the role of biological and abiological processes in sedimentation

2003 ◽  
Vol 40 (11) ◽  
pp. 1611-1642 ◽  
Author(s):  
Donald R Lowe ◽  
Deena Braunstein
Keyword(s):  
High Temperature ◽  
Yellowstone National Park ◽  
National Park ◽  
Hot Springs ◽  
Strain Effect ◽  
Temperature Sinter ◽  
Architectural Features ◽  
Siliceous Sinter ◽  
High Temperature Sinter

Slightly alkaline hot springs and geysers in Yellowstone National Park exhibit distinctive assemblages of high-temperature (>73 °C) siliceous sinter reflecting local hydrodynamic conditions. The main depositional zones include subaqueous pool and channel bottoms and intermittently wetted subaerial splash, surge, and overflow areas. Subaqueous deposits include particulate siliceous sediment and dendritic and microbial silica framework. Silica framework forms thin, porous, microbe-rich films coating subaqueous surfaces. Spicules with intervening narrow crevices dominate in splash zones. Surge and overflow deposits include pool and channel rims, columns, and knobs. In thin section, subaerial sinter is composed of (i) dark brown, nearly opaque laminated sinter deposited on surfaces that evaporate to dryness; (ii) clear translucent silica deposited subaqueously through precipitation driven by supersaturation; (iii) heterogeneous silica representing silica-encrusted microbial filaments and detritus; and (iv) sinter debris. Brownish laminations form the framework of most sinter deposited in surge and overflow zones. Pits and cavities are common architectural features of subaerial sinter and show concave-upward pseudo-cross-laminations and micro-unconformities developed through migration. Marked birefringence of silica deposited on surfaces that evaporate to dryness is probably a strain effect. Repeated wetting and evaporation, often to dryness, and capillary effects control the deposition, morphology, and microstructure of most high-temperature sinter outside of the fully subaqueous zone. Microbial filaments are abundant on and within high-temperature sinter but do not provide the main controls on morphology or structuring except in biofilms developed on subaqueous surfaces. Millimetre-scale lamination cyclicity in much high-temperature sinter represents annual layering and regular seasonal fluctuations in silica sedimentation.

scholarly journals Carbon Source Preference in Chemosynthetic Hot Spring Communities

2015 ◽  
Vol 81 (11) ◽  
pp. 3834-3847 ◽  
Author(s):  
Matthew R. Urschel ◽  
Michael D. Kubo ◽  
Tori M. Hoehler ◽  
John W. Peters ◽  
Eric S. Boyd
Keyword(s):  
High Temperature ◽  
National Park ◽  
Hot Springs ◽  
Dissolved Inorganic Carbon ◽  
Hot Spring ◽  
Affinity Constant ◽  
Rrna Gene ◽  
Organic Substrates ◽  
Short Term ◽  
Acetate Assimilation

ABSTRACTRates of dissolved inorganic carbon (DIC), formate, and acetate mineralization and/or assimilation were determined in 13 high-temperature (>73°C) hot springs in Yellowstone National Park (YNP), Wyoming, in order to evaluate the relative importance of these substrates in supporting microbial metabolism. While 9 of the hot spring communities exhibited rates of DIC assimilation that were greater than those of formate and acetate assimilation, 2 exhibited rates of formate and/or acetate assimilation that exceeded those of DIC assimilation. Overall rates of DIC, formate, and acetate mineralization and assimilation were positively correlated with spring pH but showed little correlation with temperature. Communities sampled from hot springs with similar geochemistries generally exhibited similar rates of substrate transformation, as well as similar community compositions, as revealed by 16S rRNA gene-tagged sequencing. Amendment of microcosms with small (micromolar) amounts of formate suppressed DIC assimilation in short-term (<45-min) incubations, despite the presence of native DIC concentrations that exceeded those of added formate by 2 to 3 orders of magnitude. The concentration of added formate required to suppress DIC assimilation was similar to the affinity constant (Km) for formate transformation, as determined by community kinetic assays. These results suggest that dominant chemoautotrophs in high-temperature communities are facultatively autotrophic or mixotrophic, are adapted to fluctuating nutrient availabilities, and are capable of taking advantage of energy-rich organic substrates when they become available.

Modeling and Analysis of Power Conversion System for High Temperature Gas Cooled Reactor With Cogeneration

2008 ◽  
Author(s):  
Ali Afrazeh ◽  
Hiwa Khaledi ◽  
Mohammad Bagher Ghofrani
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Gas Turbine ◽  
Power Conversion ◽  
Hot Water ◽  
Working Fluid ◽  
Closed Cycle ◽  
Nuclear Heat ◽  
Conversion System ◽  
High Temperature Gas

A gas turbine in combination with a nuclear heat source has been subject of study for some years. This paper describes the advantages of a gas turbine combined with an inherently safe and well-proven nuclear heat source. The design of the power conversion system is based on a regenerative, non-intercooled, closed, direct Brayton cycle with high temperature gas-cooled reactor (HTGR), as heat source and helium gas as the working fluid. The plant produces electricity and hot water for district heating (DH). Variation of specific heat, enthalpy and entropy of working fluid with pressure and temperature are included in this model. Advanced blade cooling technology is used in order to allow for a high turbine inlet temperature. The paper starts with an overview of the main characteristics of the nuclear heat source, Then presents a study to determine the specifications of a closed-cycle gas turbine for the HTGR installation. Attention is given to the way such a closed-cycle gas turbine can be modeled. Subsequently the sensitivity of the efficiency to several design choices is investigated. This model is developed in Fortran.

scholarly journals The Ice-Rich Permafrost Sequences as a Paleoenvironmental Archive for the Kara Sea Region (Western Arctic)

2021 ◽  
Vol 9 ◽  
Author(s):  
I. D. Streletskaya ◽  
A. A. Pismeniuk ◽  
A. A. Vasiliev ◽  
E. A. Gusev ◽  
G. E. Oblogov ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Marine Sediments ◽  
Isotope Composition ◽  
Kara Sea ◽  
Coastal Sediments ◽  
Organic Carbon Content ◽  
Ground Ice ◽  
Geochemical Composition ◽  
The Holocene ◽  
Mis 3

The Kara Sea coast and part of the shelf are characterized by wide presence of the ice-rich permafrost sequences containing massive tabular ground ice (MTGI) and ice wedges (IW). The investigations of distribution, morphology and isotopic composition of MTGI and IW allows paleoenvironmental reconstructions for Late Pleistocene and Holocene period in the Kara Sea Region. This work summarizes result of long-term research of ice-rich permafrost at eight key sites located in the Yamal, Gydan, Taimyr Peninsulas, and Sibiryakov Island. We identified several types of ground ice in the coastal sediments and summarized data on their isotopic and geochemical composition, and methane content. We summarized the available data on particle size distribution, ice chemical composition, including organic carbon content, and age of the enclosing ice sediments. The results show that Quaternary sediments of the region accumulated during MIS 5 – MIS 1 and generally consisted of two main stratigraphic parts. Ice-rich polygenetic continental sediments with syngenetic and epigenetic IW represent the upper part of geological sections (10–15 m). The IW formed in two stages: in the Late Pleistocene (MIS 3 – MIS 2) and in the Holocene cold periods. Oxygen isotope composition of IW formed during MIS 3 – MIS 2 is on average 6‰ lower than that of the Holocene IW. The saline clay with rare sand layers of the lower part of geological sections, formed in marine and shallow shelf anaerobic conditions. MTGI present in the lower part of the sections. The MTGI formed under epigenetic freezing of marine sediments immediately after sea regression and syngenetic freezing of marine sediments in the tidal zone and in the conditions of shallow sea.

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