Serpentinization and the Origin of Hydrogen Gas in Kansas (original) (raw)
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Natural H2 in Kansas: Deep or shallow origin?
Geochemistry, Geophysics, Geosystems
A new well provide the opportunity of a reappraisal of a persistent regional H 2 production in intracontiental settings, in Kansas. Two different origins are suggested for H 2 production in intra-cratonic context: a crustal origin, a surficial origin. Hypotheses of two H 2 are supported by geochemical properties of associated gases, by water associated and completion story of the well.
Keywords: abiotic methane serpentinization hydrogen isotope Serpentinite-hosted hydrothermal systems have attracted considerable attention as sites of abiotic organic synthesis and as habitats for the earliest microbial communities. Here, we report a systematic isotopic study of a new serpentinite-hosted system: the Hakuba Happo hot spring in the Shiroumadake area, Japan (36 • 42 N, 137 • 48 E). We collected water directly from the hot spring from two drilling wells more than 500 m deep; all water samples were strongly alkaline (pH > 10) and rich in H 2 (201-664 μmol/L) and CH 4 (124-201 μmol/L). Despite the relatively low temperatures (50-60 • C), thermodynamic calculations suggest that the H 2 was likely derived from serpentinization reactions.
Keywords: abiotic methane serpentinization hydrogen isotope Serpentinite-hosted hydrothermal systems have attracted considerable attention as sites of abiotic organic synthesis and as habitats for the earliest microbial communities. Here, we report a systematic isotopic study of a new serpentinite-hosted system: the Hakuba Happo hot spring in the Shiroumadake area, Japan (36 • 42 N, 137 • 48 E). We collected water directly from the hot spring from two drilling wells more than 500 m deep; all water samples were strongly alkaline (pH > 10) and rich in H 2 (201-664 μmol/L) and CH 4 (124-201 μmol/L). Despite the relatively low temperatures (50-60 • C), thermodynamic calculations suggest that the H 2 was likely derived from serpentinization reactions.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about ABSTRACT Gases occluded in fracture zones of active faults are characterized by a high concentration of H2 and/or CO2. A predominant gas species-H2 or CO2-is related to the lithofacies which the fault cuts. Carbon dioxide concentration in sediments fluctuates with temperature. This evidence and 13C of CO2 (about-20%o) suggests that CO2 originates from organic materials. Carbon dioxide with 813C of-5%o to-17%o in brecciated gneiss containing marble may have been produced by interaction between organically derived CO2 and the marble, or alternatively, may have been magmatically derived. Hydrogen usually occurs in sheared silicate rocks, and its concentration fluctuates a great deal. The concentration of H2 from active faults associated with historical earthquakes usually amounts to as high as several percent in maximum, whereas the concentration of H2 from Quaternary faults not associated with historical earthquakes is at most 100 ppm. Laboratory experiments showed that much H2 is generated from paste made of newly pulverized rocks and water, suggesting that the fresh mineral surface formed by tectonic stresses reacts with groundwater to produce H2. Since the mineral surface loses its activity with time, discrimination between recently moved faults and other Quaternary faults can be made by the H2 concentration. Hydrogen isotope thermometer, as well as field evidence, suggests a deep seated origin of H2 in an active fault. Hydrogen measurements at monitoring stations offer information at depth on mechanisms that operate prior to earthquakes.
Natural hydrogen potential and basaltic alteration in the Asal-Ghoubbet rift, Republic of Djibouti
2023
The Asal-Ghoubbet active rift in the Republic of Djibouti is a site of interest for geothermal energy and natural hydrogen, and previous studies have indicated that dihydrogen (H 2) emanates from this rift. However, the well-known serpentinization reaction does not appear to be the main mechanism generating H 2 at this site. Rather, the H 2 is generated as follows: (1) by alteration of basaltic lava at depth via reaction with seawater flowing from Ghoubbet Bay towards Lake Asal; (2) by simple degassing of the volcanic chamber located a few kilometers below the Fiale Caldera in the rift axis; or (3) as a result of pyritization processes via the oxidation of H 2 S. Study of microorganisms did not indicate any production or consumption of H 2 , CO 2 , or CH 4 ; therefore, it is unlikely that microorganisms affected H 2 gas contents measured at the surface. However, air contamination at fumaroles is typically considerable and may limit interpretation of such processes. Drill cuttings from the Fiale 1 (F1) and Gale le Goma 1 (Glc1) wells (located on the inner and outer rift margins, respectively) were analyzed to determine where H 2 is generated. Total rock analyses indicated distinct zones at depths of 464 m and 280 m for F1 and Glc1, respectively, representing the boundary between the Asal and Stratoïd Basalts. 57 Fe Mössbauer analyses show a decrease in the percentage of Fe 3þ at depth, indicating that Fe 2þ-rich minerals, particularly in the Stratoïd Basalts, may be a source of H 2. Based on well data from the rift center and the outer rift margin, it is evident that H 2 is present at the surface in the rift axis and that this area offers good remnant potential because of the presence of Fe-rich chlorite. Conversely, few H 2 emissions were measured at the surface on the outer rift margins, although well data showed some H 2 (∼0.25%) at depth. The presence of a cap rock in the rift axis has not yet been proven; however, the high loss on ignition and the mineralogy in well Glc1 may indicate that the rocks are sufficiently altered into clays to offer potential as a H 2 seal. If so, the rift margins would offer greater exploration potential than the rift center.
H 2 -rich fluids from serpentinization: Geochemical and biotic implications
Proceedings of the National Academy of Sciences, 2004
Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi 3 , forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impact. This process formed some of the ferric iron in the Earth's mantle. For the rest of Earth's history, serpentinites covered only a small fraction of the Earth's surface but were an important prebiotic and biotic environment. Extant methanogens react H 2 with CO 2 to form methane. This is a likely habitable environment on large silicate planets. The catalytic properties of FeNi 3 allow complex organic compounds to form within serpentinite and, when mixed with atmospherically produc...
Mineralogical evidence for H 2 degassing during serpentinization at 300 °C/300 bar
Earth and Planetary Science Letters, 2011
Keywords: hydrogen serpentine XANES hydrothermal field Hydrogen is produced in large amounts during hydrothermal alteration of peridotite in low-spreading-rate mid-ocean ridges. This production is directly linked to reducing conditions in hydrothermal fluids induced by the oxidation of Fe 2+ in primary minerals (olivine and pyroxene) to Fe 3+ in secondary minerals (magnetite and serpentine). A better knowledge of iron speciation in serpentine is therefore crucial to the quantification of hydrogen production during the serpentinization process. For the first time, we have determined the amount of ferric iron in altered peridotite as a function of alteration time. We investigated experimentally the alteration of powdered lherzolite in pure water at 300°C/300 bar. For each experimental run (0, 7, 18, 34 and 70 days), H 2 degassing was measured using in-situ gas chromatography and the experimental products were analyzed using XRD, Raman and X-ray absorption spectroscopy at the iron K-edge. In parallel, aqueous solutions were analyzed by ICP-AES. Our results show quasi-complete serpentinization at 70 days with replacement of primary olivine and pyroxene by secondary lizardite and magnetite. The Fe 3+ /Fe total ratio is linearly dependent on the hydrogen production and ranges from 0 to 0.66 at the end of the experiment. Our results reveal strong variations in Fe 3+ in serpentine for different alteration times, from 0 to 100% of ferric iron, including up to 12% of tetrahedral iron. Hydrogen was produced in three main stages: (1) a first stage during which the H 2 production rate reaches a maximum at 18 days and is controlled by the crystallization of magnetite, (2) an intermediate stage during which serpentine incorporates ferric iron and thus plays a major role (up to 50%) in the hydrogen formation, and (3) a final stage during which magnetite amount increases from~2 to~5% of the mineral assemblage. The last alteration stage is accompanied by a slight increase of the Fe 3+ /Fe total ratio, while the rate of hydrogen production decreases at the end of the experiment. Consequently, variations of the ferric iron contents in natural oceanic peridotites may constitute a good indicator of the "hydrogen-potential" of various ultramafic hydrothermal fields.
Diffused flow of molecular hydrogen through the Western Hajar mountains, Northern Oman
Arabian Journal of Geosciences
We report the discovery of a general, diffused flow of molecular hydrogen (H 2) through the Western Hajar mountains of Northern Oman. H 2 was detected across a fracture system in the peridotites of the Semail ophiolite massif, and no traces of this gas were found in unfractured peridotites. H 2 seeps in these rocks have been classically interpreted to be the result of reduction of groundwater during the process of peridotite serpentinization. However, there is evidence of hydrogen seepage in other geological units of Northern Oman, particularly in the Precambrian to Early Permian metamorphic sequences of the Jebel Akhdar massif, and to a lesser extent in the Hawasina sequence underthrust beneath the ophiolitic units. As a consequence, hydrogen flows are also being detected from geological formations structurally located below the ophiolites. Our sampling shows that increased flow is not observed in the peridotites, but in the deeper stratigraphic and structural units (Upper Proterozoic). These observations suggest a source of H 2 existing below the ophiolites. Minimum estimated H 2 flows using various methods range from 70 to 150 m 3 /km 2 per day from peridotites and up to 1300 m 3 /km 2 per day from the Upper Proterozoic.