Evaluation of Caldera Hosted Geothermal Potential during Volcanism and Magmatism in Subduction System, NE Japan

Deep-seated geothermal reservoirs beneath calderas have high potential as sources of renewable energy. In this study, we used an analysis of melt inclusions to estimate the amount of water input to the upper crust and quantify the properties of a deep-seated geothermal reservoir within a fossil caldera, the late Miocene Fukano Caldera (formation age 8–6 Ma), Sendai, NE Japan. Our research shows that Fukano Caldera consists of the southern part and northern part deposits which differ in the age and composition. The northern deposits are older and have higher potassium and silica contents than the southern deposits. Both the northern and southern deposits record plagioclase and plagioclase–quartz differentiation and are classified as dacite–rhyolite. The fossil magma chamber underlying the caldera is estimated to have a depth of ~2–10 km and a water content of 3.3–7.0 wt.%, and when the chamber was active it had an estimated temperature of 750°C–795°C. The water input into the fossil magma chamber is estimated at 2.3–7.6 t/yr/m arc length based on the magma chamber size the water content in the magma chamber and the length of volcanism periods of Fukano Caldera, NE Japan arc. The total amount of water that is stored in the chamber is ~1014 kg. The chamber is saturated in water and has potential as a deep-seated geothermal reservoir. Based on the shape of the chamber, the reservoir measures ~10 km × 5 km in the horizontal dimension and is 7–9 km in vertical extent. The 0th estimate shows that the reservoir can hold the electric energy equivalent of 33–45 GW over 30 years of power generation. Although the Fukano reservoir has great potential, commercial exploitation remains challenging owing to the corrosive nature of the magmatic fluids and the uncertain permeability network of the reservoir.

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MAGMA CHAMBER DYNAMICS AND ERUPTIVE MECHANISMS IN THE CASCADE ARC: INSIGHTS FROM MELT INCLUSIONS AND TITANIUM-IN-QUARTZ THERMOBAROMETRY

10.1130/abs/2017am-308453 ◽

2017 ◽

Author(s):

Jeremy S. Rosen ◽

◽

Brian G. Rusk ◽

Michael A. Clynne ◽

Susan M. DeBari

Keyword(s):

Magma Chamber ◽

Melt Inclusions ◽

Cascade Arc

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Constraining Mantle Heterogeneity beneath the South China Sea: A New Perspective on Magma Water Content

Minerals ◽

10.3390/min9070410 ◽

2019 ◽

Vol 9 (7) ◽

pp. 410 ◽

Cited By ~ 1

Author(s):

Wei Wang ◽

Fengyou Chu ◽

Xichang Wu ◽

Zhenggang Li ◽

Ling Chen ◽

...

Keyword(s):

South China Sea ◽

Water Content ◽

South China ◽

Mantle Source ◽

Melt Inclusions ◽

The South China Sea ◽

Spreading Ridge ◽

Mantle Heterogeneity ◽

The South ◽

China Sea

The nature of upper mantle is important to understand the evolution of the South China Sea (SCS); thus, we need better constrains on its mantle heterogeneity. Magma water concentration is a good indicator, but few data have been reported. However, the rarity of glass and melt inclusions and the special genesis for phenocrysts in SCS basalts present challenges to analyzing magmatic water content. Therefore, it is possible to estimate the water variations through the characteristics of partial melting and magma crystallization. We evaluated variations in Fe depletion, degree of melt fractions, and mantle source composition along the fossil spreading ridge (FSR) using SCS basalt data from published papers. We found that lava from the FSR 116.2° E, FSR 117.7° E, and non-FSR regions can be considered normal lava with normal water content; in contrast, lava from the FSR 117° E-carbonatite and 114.9–115.0° E basalts have higher water content and show evidence of strong Fe depletion during the fractional crystallization after elimination of the effects of plagioclase oversaturation. The enriched water in the 117° E-carbonatite basalts is contained in carbonated silicate melts, and that in the 114.9–115.0° E basalts results from mantle contamination with the lower continental crust. The lava from the 117° E-normal basalt has much lower water content because of the lesser influence of the Hainan plume. Therefore, there must be a mantle source compositional transition area between the southwestern and eastern sub-basins of the SCS, which have different mantle evolution histories. The mantle in the west is more affected by contamination with continental materials, while that in the east is more affected by the Hainan mantle plume.

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Post-drying of energy sorrel in a grate stock

Research in Agricultural Engineering ◽

10.17221/4921-rae ◽

2012 ◽

Vol 50 (No. 1) ◽

pp. 15-22

Author(s):

P. Hutla ◽

J. Mazancová

Keyword(s):

Water Content ◽

Electric Energy ◽

Energy Crop ◽

Yield Potential ◽

High Yield ◽

Large Capacity ◽

The Czech Republic ◽

Time Switching ◽

Operational Conditions ◽

Short Time

Energy sorrel is a crop with high-yield potential and belongs among the most promissing energy crop for the Czech Republic. The suitable processing technology is harvest by the harvesting cutter with subsequent short-time storage and post-drying of chopped material in the large-capacity hayloft. For chopped sorrel were found-out hydraulic air losses during its passing through the stored layer and they were compared with values for stored forage. Two methods of drying ventilators controlling in the large-capacity heyloft were compared with the regime of time switching within chopped sorrel drying. Electric energy comsumption for ventilators drive in different regimes depends on water content in the material. Method of ventilators or time switching controlling has no effect on drying process result, thus even on water content reduction in the dried material. Under operational conditions the possibility of the chopped energy sorrel in large-capacity heyloft was verified.

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The quality of geothermal reservoir of the Lower Jurassic aquifer in the Mogilno-Łódź Trough (Polish Lowlands)

E3S Web of Conferences ◽

10.1051/e3sconf/201913302004 ◽

2019 ◽

Vol 133 ◽

pp. 02004 ◽

Cited By ~ 1

Author(s):

Aleksandra Kasztelewicz ◽

Barbara Tomaszewska

Keyword(s):

Grain Size ◽

Heat Production ◽

Lower Jurassic ◽

Geothermal Reservoir ◽

Accurate Identification ◽

Geothermal Potential ◽

Geological Conditions ◽

Temperature Ranges ◽

Water Accumulation

The assessment of the geothermal potential should always take an accurate identification of the geological conditions into account. Petrographic and petrophysical investigations of the aquifers allow to estimate their productivity and infectivity. The area of the Mogilno-Łódź Trough is next to the Podhale basin, one of the most prospective regions in terms of geothermal potential in Poland. The Lower Jurassic aquifers are characterized by the largest dispositional resources among geothermal aquifers in the Polish Lowlands. The Lower Jurassic geothermal reservoir consist of fine and mixed grain-size sands and sandstones layers from 10-650 m thick, depending on the depth. The water within the reservoir exhibits mineralization ranging from 2 to over 250 g/L and its temperature ranges from 30 to 100°C. Boreholes profiles selected for study consist Lower Jurassic formations of the Polish Lowlands, which are perspective for the heat production in Poland. Sandstones are represent mainly by quartz arenites and subordinate by quartz wackes. Parameters measured include among others porosity, permeability and surface area. The results of the petrographic and mineralogical studies of core samples confirmed the presence of rock with favorable parameters for geothermal water accumulation.

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A critical magma chamber size for volcanic eruptions

Geology ◽

10.1130/g47045.1 ◽

2020 ◽

Vol 48 (5) ◽

pp. 431-435 ◽

Cited By ~ 1

Author(s):

Meredith Townsend ◽

Christian Huber

Keyword(s):

Magma Chamber ◽

Scaling Law ◽

Volcanic Eruptions ◽

Elastic Response ◽

Chamber Pressure ◽

Pressure Drops ◽

Chamber Volume ◽

Intermediate Chamber ◽

History Of ◽

Chamber Size

Abstract We present a model for a coupled magma chamber–dike system to investigate the conditions required to initiate volcanic eruptions and to determine what controls the size of eruptions. The model combines the mechanics of dike propagation with internal chamber dynamics including crystallization, volatile exsolution, and the elastic response of the magma and surrounding crust to pressure changes within the chamber. We find three regimes for dike growth and eruptions: (1) below a critical magma chamber size, eruptions are suppressed because chamber pressure drops to lithostatic before a dike reaches the surface; (2) at an intermediate chamber size, the erupted volume is less than the dike volume (“dike-limited” eruption regime); and (3) above a certain chamber size, dikes can easily reach the surface and the erupted volume follows a classic scaling law, which depends on the attributes of the magma chamber (“chamber-limited” eruption regime). The critical chamber volume for an eruption ranges from ∼0.01 km3 to 10 km3 depending on the water content in the magma, depth of the chamber, and initial overpressure. This implies that the first eruptions at a volcano likely are preceded by a protracted history of magma chamber growth at depth, and that the crust above the magma chamber may have trapped several intrusions or “failed eruptions.” Model results can be combined with field observations of erupted volume, pressure, and crystal and volatile content to provide tighter constraints on parameters such as the eruptible chamber size.

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Glass-bearing felsic nodules from the crystallizing sidewalls of the 1944 Vesuvius magma chamber

Mineralogical Magazine ◽

10.1180/002646100549373 ◽

2000 ◽

Vol 64 (3) ◽

pp. 481-496 ◽

Cited By ~ 15

Author(s):

P. Fulignati ◽

P. Marianelli ◽

A. Sbrana

Keyword(s):

Magma Chamber ◽

Melt Inclusions ◽

Mineral Chemistry ◽

Glassy Matrix ◽

Crystal Mush ◽

Stratigraphic Sequence ◽

Shallow Magma Chamber ◽

Mineral Assemblages ◽

Pressure Crystallization

AbstractIn the 1944 Vesuvius eruption, the shallow magma chamber was disrupted during the highly energetic explosive phases. Abundant cognate xenoliths such as subvolcanic fergusites and cumulates, hornfels, skarns and rare marbles occur in tephra deposits.Mineral chemistry, melt inclusions in minerals and glassy matrix compositions show that fergusites (highly crystalline rocks made of leucite, clinopyroxene, plagioclase, olivine, apatite, oxides and glass) do not correspond to melt compositions but result from combined sidewall accumulation of crystals, formed from K-tephriphonolitic magma resident in the chamber, and in situ crystallization of the intercumulus melt. Very low H2O contents in the intercumulus glass are revealed by FTIR and apatite composition. Whole rock compositions are essentially determined by the bulk mineral assemblages.Glass–bearing fergusites constitute the outer shell of the magma chamber consisting of a highly viscous crystal mush with a melt content in the range 20–50 wt.%. The leucite/(clinopyroxene+olivine) modal ratio, varies with the extraction order of magmas from the chamber, decreasing upwards in the stratigraphic sequence. This reflects a vertical mineralogical zonation of the crystal mush. These data contribute to the interpretation of the subvolcanic low–pressure crystallization processes at the magma chamber sidewalls affecting alkaline potassic magmas.

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Magma chamber decompression during explosive caldera-forming eruption of Aira caldera

Communications Earth & Environment ◽

10.1038/s43247-021-00272-x ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Nobuo Geshi ◽

Tadashi Yamasaki ◽

Isoji Miyagi ◽

Chris E. Conway

Keyword(s):

Pressure Drop ◽

Water Content ◽

Magma Chamber ◽

Quartz Glass ◽

Roof Rock ◽

Theoretical Models ◽

Caldera Collapse ◽

Magma Chambers ◽

Pyroclastic Deposits ◽

Fundamental Condition

AbstractDecompression of a magma chamber is a fundamental condition of caldera collapse. Although theoretical models have predicted the decompression of magma chambers before caldera collapse, few previous studies have demonstrated the amount of magma chamber decompression. Here, we determine water content in quartz glass embayments and inclusions from pyroclastic deposits of a caldera-forming eruption at Aira volcano approximately 30,000 years ago and apply this data to calculate decompression inside the magma chamber. We identify a pressure drop from 140–260 MPa to 20–90 MPa during the extraction of around 50 km3 of magma prior to the caldera collapse. The magma extraction may have caused down-sag subsidence at the caldera center before the onset of catastrophic caldera collapse. We propose that this deformation resulted in the fracturing and collapse of the roof rock into the magma chamber, leading to the eruption of massive ignimbrite.

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