Tracking the thermal properties of the lower continental crust: Measured versus calculated thermal conductivity of high-grade metamorphic rocks (Southern Granulite Province, India).
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| Title: | Tracking the thermal properties of the lower continental crust: Measured versus calculated thermal conductivity of high-grade metamorphic rocks (Southern Granulite Province, India). |
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| Authors: | Ray, Labani1 labani@ngri.res.in, Förster, Hans-Jürgen2, Förster, Andrea2, Fuchs, Sven3, Naumann, Rudolf2, Appelt, Oona2 |
| Source: | Geothermics. May2015, Vol. 55, p138-149. 12p. |
| Subjects: | Thermal conductivity, Metamorphic rocks, Granulite, Sedimentary rocks, Igneous rocks, Anisotropy |
| Geographic Terms: | Iran |
| Abstract: | In this study, the bulk thermal conductivity (TC) of 26 rock samples representing different types of granulite-facies rocks, i.e., felsic, intermediate and mafic granulites, from the Southern Granulite Province, India, is measured at dry and saturated conditions with the optical-scanning method. Thermal conductivity is also calculated from modal mineralogy (determined by XRD and EPMA), applying several mixing models commonly used in thermal studies. Most rocks are fine- to medium-grained equigranular in texture. All samples are isotropic to weakly anisotropic and possess low porosities (<2%). Measured TC values range between 2.5 and 3.0 W m −1 K −1 for felsic granulites, between 2.5 and 3.5 W m −1 K −1 for intermediate granulites and between 2.4 and 2.7 W m −1 K −1 for mafic granulites. Considering this data and literature compilations, rocks representative for the lower continental crust typically display values between 2 and 3 W m −1 K −1 at ambient temperature and pressure conditions. Depending on the mixing model and the mineral TC value used in the calculations, measured and calculated bulk TC could be properly fitted. For mean values of mineral TCs, the harmonic mean provides an almost perfect fit, with a mean deviation of −1 ± 6% (1 σ ). However, the implication of that correspondence would be that minerals and pores are predominantly aligned parallel, which is in apparent contrast to the texture of the rocks studied here. The geometric mean, which does not consider any layering of minerals or pores in the rock and, thus, should be in better harmony with the textural characteristics of the studied high-grade rocks, matches the measured TC data very well, if minimal minerals TCs reported in the literature are applied (mean deviation 5 ± 8%). Thus, if samples appropriate for laboratory measurements (in terms of sample size or physical-chemical-mechanical condition) are not available, bulk TC of high-grade metamorphic rocks with low anisotropy and porosity could be satisfactorily good assessed from modal mineralogy, using the data sets for mineral TC applied in this study. Further work is required on the applicability of mixing models to compute TC of other rock types, e.g., of igneous and sedimentary rocks. [ABSTRACT FROM AUTHOR] |
| Copyright of Geothermics is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 101910221 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Tracking the thermal properties of the lower continental crust: Measured versus calculated thermal conductivity of high-grade metamorphic rocks (Southern Granulite Province, India). – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Ray%2C+Labani%22">Ray, Labani</searchLink><relatesTo>1</relatesTo><i> labani@ngri.res.in</i><br /><searchLink fieldCode="AR" term="%22Förster%2C+Hans-Jürgen%22">Förster, Hans-Jürgen</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Förster%2C+Andrea%22">Förster, Andrea</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Fuchs%2C+Sven%22">Fuchs, Sven</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Naumann%2C+Rudolf%22">Naumann, Rudolf</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Appelt%2C+Oona%22">Appelt, Oona</searchLink><relatesTo>2</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Geothermics%22">Geothermics</searchLink>. May2015, Vol. 55, p138-149. 12p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Thermal+conductivity%22">Thermal conductivity</searchLink><br /><searchLink fieldCode="DE" term="%22Metamorphic+rocks%22">Metamorphic rocks</searchLink><br /><searchLink fieldCode="DE" term="%22Granulite%22">Granulite</searchLink><br /><searchLink fieldCode="DE" term="%22Sedimentary+rocks%22">Sedimentary rocks</searchLink><br /><searchLink fieldCode="DE" term="%22Igneous+rocks%22">Igneous rocks</searchLink><br /><searchLink fieldCode="DE" term="%22Anisotropy%22">Anisotropy</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Iran%22">Iran</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: In this study, the bulk thermal conductivity (TC) of 26 rock samples representing different types of granulite-facies rocks, i.e., felsic, intermediate and mafic granulites, from the Southern Granulite Province, India, is measured at dry and saturated conditions with the optical-scanning method. Thermal conductivity is also calculated from modal mineralogy (determined by XRD and EPMA), applying several mixing models commonly used in thermal studies. Most rocks are fine- to medium-grained equigranular in texture. All samples are isotropic to weakly anisotropic and possess low porosities (<2%). Measured TC values range between 2.5 and 3.0 W m −1 K −1 for felsic granulites, between 2.5 and 3.5 W m −1 K −1 for intermediate granulites and between 2.4 and 2.7 W m −1 K −1 for mafic granulites. Considering this data and literature compilations, rocks representative for the lower continental crust typically display values between 2 and 3 W m −1 K −1 at ambient temperature and pressure conditions. Depending on the mixing model and the mineral TC value used in the calculations, measured and calculated bulk TC could be properly fitted. For mean values of mineral TCs, the harmonic mean provides an almost perfect fit, with a mean deviation of −1 ± 6% (1 σ ). However, the implication of that correspondence would be that minerals and pores are predominantly aligned parallel, which is in apparent contrast to the texture of the rocks studied here. The geometric mean, which does not consider any layering of minerals or pores in the rock and, thus, should be in better harmony with the textural characteristics of the studied high-grade rocks, matches the measured TC data very well, if minimal minerals TCs reported in the literature are applied (mean deviation 5 ± 8%). Thus, if samples appropriate for laboratory measurements (in terms of sample size or physical-chemical-mechanical condition) are not available, bulk TC of high-grade metamorphic rocks with low anisotropy and porosity could be satisfactorily good assessed from modal mineralogy, using the data sets for mineral TC applied in this study. Further work is required on the applicability of mixing models to compute TC of other rock types, e.g., of igneous and sedimentary rocks. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Geothermics is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.geothermics.2015.01.007 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 12 StartPage: 138 Subjects: – SubjectFull: Thermal conductivity Type: general – SubjectFull: Metamorphic rocks Type: general – SubjectFull: Granulite Type: general – SubjectFull: Sedimentary rocks Type: general – SubjectFull: Igneous rocks Type: general – SubjectFull: Anisotropy Type: general – SubjectFull: Iran Type: general Titles: – TitleFull: Tracking the thermal properties of the lower continental crust: Measured versus calculated thermal conductivity of high-grade metamorphic rocks (Southern Granulite Province, India). Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Ray, Labani – PersonEntity: Name: NameFull: Förster, Hans-Jürgen – PersonEntity: Name: NameFull: Förster, Andrea – PersonEntity: Name: NameFull: Fuchs, Sven – PersonEntity: Name: NameFull: Naumann, Rudolf – PersonEntity: Name: NameFull: Appelt, Oona IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 05 Text: May2015 Type: published Y: 2015 Identifiers: – Type: issn-print Value: 03756505 Numbering: – Type: volume Value: 55 Titles: – TitleFull: Geothermics Type: main |
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