Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones
Only few data from geothermal exploited reservoirs are available due to the restricted accessibility by drilling, which limits the understanding of the entire reservoir. Thus, analogue investigations are needed and were performed in the framework of the H2020 MEET project. The Noble Hills range, loc...
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| Format: | Article |
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MDPI AG
2021-07-01
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| Online Access: | https://www.mdpi.com/2076-3263/11/8/325 |
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| author | Johanne Klee Sébastien Potel Béatrice A. Ledésert Ronan L. Hébert Arezki Chabani Pascal Barrier Ghislain Trullenque |
| author_facet | Johanne Klee Sébastien Potel Béatrice A. Ledésert Ronan L. Hébert Arezki Chabani Pascal Barrier Ghislain Trullenque |
| author_sort | Johanne Klee |
| collection | DOAJ |
| description | Only few data from geothermal exploited reservoirs are available due to the restricted accessibility by drilling, which limits the understanding of the entire reservoir. Thus, analogue investigations are needed and were performed in the framework of the H2020 MEET project. The Noble Hills range, located along the southern branch of the Death Valley pull-apart (CA, USA), has been selected as a possible granitic paleo-reservoir. The aim is to characterize the pervasive alteration processes affecting this granite, away from the influence of the faults, in terms of mineralogical, petrophysical and chemical changes. Various methods were used as petrographic, geochemical and petrophysical analyses. Mineral changes, clay mineralogy, bulk rock chemical composition, calcite content and porosity were determined on different granite samples, collected in the Noble Hills granite, far from the faults and in the Owlshead Mountains, north of the Noble Hills, considered as its protolith. In order to complete the granite characterization, the metamorphic grade has been studied through the Noble Hills granite body. This complete characterization has allowed distinguishing the occurrence of three stages of alteration: (1) a pervasive propylitic alteration characterized by calcite-corrensite-epidote-K-white mica assemblage, (2) a more local one, only present in the Noble Hills granite, producing illite, kaolinite, illite/smectite, calcite and oxides, characteristic of the argillic alteration, which overprints the propylitic alteration and (3) weathering evidenced by the presence of montmorillonite in the Owlshead Mountains, which is considered as negligible in both granites. Alteration was also outlined by the correlation of the loss on ignition, representing the hydration rate, to porosity, calcite content and chemical composition. Moreover, the Kübler Index calculated from illite crystals allowed to identify a NW-SE temperature gradient in the Noble Hills. |
| first_indexed | 2024-03-10T08:46:59Z |
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| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-03-10T08:46:59Z |
| publishDate | 2021-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Geosciences |
| spelling | doaj.art-93fdc0d538f5499e91b24ab0a811bfe32023-11-22T07:47:48ZengMDPI AGGeosciences2076-32632021-07-0111832510.3390/geosciences11080325Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture ZonesJohanne Klee0Sébastien Potel1Béatrice A. Ledésert2Ronan L. Hébert3Arezki Chabani4Pascal Barrier5Ghislain Trullenque6B2R, Geosciences Department, Institut Polytechnique UniLaSalle Beauvais, 19 Rue Pierre Waguet, F-60026 Beauvais, FranceB2R, Geosciences Department, Institut Polytechnique UniLaSalle Beauvais, 19 Rue Pierre Waguet, F-60026 Beauvais, FranceGeosciences and Environment Cergy, CY Cergy Paris Université, 1 Rue Descartes, F-95000 Neuville-sur-Oise, FranceGeosciences and Environment Cergy, CY Cergy Paris Université, 1 Rue Descartes, F-95000 Neuville-sur-Oise, FranceB2R, Geosciences Department, Institut Polytechnique UniLaSalle Beauvais, 19 Rue Pierre Waguet, F-60026 Beauvais, FranceB2R, Geosciences Department, Institut Polytechnique UniLaSalle Beauvais, 19 Rue Pierre Waguet, F-60026 Beauvais, FranceB2R, Geosciences Department, Institut Polytechnique UniLaSalle Beauvais, 19 Rue Pierre Waguet, F-60026 Beauvais, FranceOnly few data from geothermal exploited reservoirs are available due to the restricted accessibility by drilling, which limits the understanding of the entire reservoir. Thus, analogue investigations are needed and were performed in the framework of the H2020 MEET project. The Noble Hills range, located along the southern branch of the Death Valley pull-apart (CA, USA), has been selected as a possible granitic paleo-reservoir. The aim is to characterize the pervasive alteration processes affecting this granite, away from the influence of the faults, in terms of mineralogical, petrophysical and chemical changes. Various methods were used as petrographic, geochemical and petrophysical analyses. Mineral changes, clay mineralogy, bulk rock chemical composition, calcite content and porosity were determined on different granite samples, collected in the Noble Hills granite, far from the faults and in the Owlshead Mountains, north of the Noble Hills, considered as its protolith. In order to complete the granite characterization, the metamorphic grade has been studied through the Noble Hills granite body. This complete characterization has allowed distinguishing the occurrence of three stages of alteration: (1) a pervasive propylitic alteration characterized by calcite-corrensite-epidote-K-white mica assemblage, (2) a more local one, only present in the Noble Hills granite, producing illite, kaolinite, illite/smectite, calcite and oxides, characteristic of the argillic alteration, which overprints the propylitic alteration and (3) weathering evidenced by the presence of montmorillonite in the Owlshead Mountains, which is considered as negligible in both granites. Alteration was also outlined by the correlation of the loss on ignition, representing the hydration rate, to porosity, calcite content and chemical composition. Moreover, the Kübler Index calculated from illite crystals allowed to identify a NW-SE temperature gradient in the Noble Hills.https://www.mdpi.com/2076-3263/11/8/325Noble Hills graniteOwlshead Mountains granitemetamorphic gradefluid/rock interactionsnewly formed mineralselement variations |
| spellingShingle | Johanne Klee Sébastien Potel Béatrice A. Ledésert Ronan L. Hébert Arezki Chabani Pascal Barrier Ghislain Trullenque Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones Geosciences Noble Hills granite Owlshead Mountains granite metamorphic grade fluid/rock interactions newly formed minerals element variations |
| title | Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones |
| title_full | Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones |
| title_fullStr | Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones |
| title_full_unstemmed | Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones |
| title_short | Fluid-Rock Interactions in a Paleo-Geothermal Reservoir (Noble Hills Granite, California, USA). Part 1: Granite Pervasive Alteration Processes away from Fracture Zones |
| title_sort | fluid rock interactions in a paleo geothermal reservoir noble hills granite california usa part 1 granite pervasive alteration processes away from fracture zones |
| topic | Noble Hills granite Owlshead Mountains granite metamorphic grade fluid/rock interactions newly formed minerals element variations |
| url | https://www.mdpi.com/2076-3263/11/8/325 |
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