Rheology and flow of crystal-bearing lavas: Insights from analogue gravity currents
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| Title: | Rheology and flow of crystal-bearing lavas: Insights from analogue gravity currents |
|---|---|
| Authors: | Castruccio, Angelo1,2 angelo.castruccio@bristol.ac.uk, Rust, A.C.1, Sparks, R.S.J.1 |
| Source: | Earth & Planetary Science Letters. Sep2010, Vol. 297 Issue 3/4, p471-480. 10p. |
| Subjects: | Crystals, Rheology, Gravity, Lava flows, Strength of materials, Particle size distribution, Case studies |
| Abstract: | Abstract: The rheology of suspensions of cubic crystals in viscous liquids was investigated with a series of experiments, consisting of the release of a fixed volume of fluid inside a horizontal channel. A Herschel–Bulkley rheology was assumed and the consistency K and the shear rate exponent n of this constitutive equation were calculated using the evolution of the flow front; the yield strength was calculated using the final shape of the flow. A solid fraction by volume of ϕ =0–0.67 and a liquid viscosity range of 1–370Pas were used in the experiments. Results show an increase in K when crystal content increases. The mixtures start to show a shear thinning behaviour at ϕ ~0.3 with n values going from approximately 1 (Newtonian behaviour) to 0.5 at ϕ =0.6. Yield strength was detected at the same ϕ as the beginning of shear thinning behaviour and increases with a power-law relationship with crystal content. Suspensions with bimodal size distribution of crystals show a dramatic decrease of the apparent viscosity compared to unimodal suspensions, especially at the higher total crystal concentrations. The results were applied to theoretical 2-D flows on a slope, showing large variations in velocity profiles for the same crystallinity depending on the rheology assumed. A case study of a 2002 lava flow from Etna volcano demonstrates that measured lava flow speeds are similar to speeds calculated from 2-D theory with rheologies of lava based on laboratory experiments and measured lava crystal content. The results illustrate that the dynamics of lava flows depend on the crystal size distribution in addition to the total crystal concentration. [ABSTRACT FROM AUTHOR] |
| Copyright of Earth & Planetary Science Letters is the property of Elsevier B.V. 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: 53335567 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Rheology and flow of crystal-bearing lavas: Insights from analogue gravity currents – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Castruccio%2C+Angelo%22">Castruccio, Angelo</searchLink><relatesTo>1,2</relatesTo><i> angelo.castruccio@bristol.ac.uk</i><br /><searchLink fieldCode="AR" term="%22Rust%2C+A%2EC%2E%22">Rust, A.C.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Sparks%2C+R%2ES%2EJ%2E%22">Sparks, R.S.J.</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Earth+%26+Planetary+Science+Letters%22">Earth & Planetary Science Letters</searchLink>. Sep2010, Vol. 297 Issue 3/4, p471-480. 10p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Crystals%22">Crystals</searchLink><br /><searchLink fieldCode="DE" term="%22Rheology%22">Rheology</searchLink><br /><searchLink fieldCode="DE" term="%22Gravity%22">Gravity</searchLink><br /><searchLink fieldCode="DE" term="%22Lava+flows%22">Lava flows</searchLink><br /><searchLink fieldCode="DE" term="%22Strength+of+materials%22">Strength of materials</searchLink><br /><searchLink fieldCode="DE" term="%22Particle+size+distribution%22">Particle size distribution</searchLink><br /><searchLink fieldCode="DE" term="%22Case+studies%22">Case studies</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Abstract: The rheology of suspensions of cubic crystals in viscous liquids was investigated with a series of experiments, consisting of the release of a fixed volume of fluid inside a horizontal channel. A Herschel–Bulkley rheology was assumed and the consistency K and the shear rate exponent n of this constitutive equation were calculated using the evolution of the flow front; the yield strength was calculated using the final shape of the flow. A solid fraction by volume of ϕ =0–0.67 and a liquid viscosity range of 1–370Pas were used in the experiments. Results show an increase in K when crystal content increases. The mixtures start to show a shear thinning behaviour at ϕ ~0.3 with n values going from approximately 1 (Newtonian behaviour) to 0.5 at ϕ =0.6. Yield strength was detected at the same ϕ as the beginning of shear thinning behaviour and increases with a power-law relationship with crystal content. Suspensions with bimodal size distribution of crystals show a dramatic decrease of the apparent viscosity compared to unimodal suspensions, especially at the higher total crystal concentrations. The results were applied to theoretical 2-D flows on a slope, showing large variations in velocity profiles for the same crystallinity depending on the rheology assumed. A case study of a 2002 lava flow from Etna volcano demonstrates that measured lava flow speeds are similar to speeds calculated from 2-D theory with rheologies of lava based on laboratory experiments and measured lava crystal content. The results illustrate that the dynamics of lava flows depend on the crystal size distribution in addition to the total crystal concentration. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Earth & Planetary Science Letters is the property of Elsevier B.V. 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.epsl.2010.06.051 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 10 StartPage: 471 Subjects: – SubjectFull: Crystals Type: general – SubjectFull: Rheology Type: general – SubjectFull: Gravity Type: general – SubjectFull: Lava flows Type: general – SubjectFull: Strength of materials Type: general – SubjectFull: Particle size distribution Type: general – SubjectFull: Case studies Type: general Titles: – TitleFull: Rheology and flow of crystal-bearing lavas: Insights from analogue gravity currents Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Castruccio, Angelo – PersonEntity: Name: NameFull: Rust, A.C. – PersonEntity: Name: NameFull: Sparks, R.S.J. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 09 Text: Sep2010 Type: published Y: 2010 Identifiers: – Type: issn-print Value: 0012821X Numbering: – Type: volume Value: 297 – Type: issue Value: 3/4 Titles: – TitleFull: Earth & Planetary Science Letters Type: main |
| ResultId | 1 |
