The in vacuo release of Ar from minerals: 1. hydrous minerals

Villa, Igor M. (2021). The in vacuo release of Ar from minerals: 1. hydrous minerals. Chemical geology, 564(120076), pp. 1-9. Elsevier 10.1016/j.chemgeo.2021.120076

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The systematics of Ar release during in vacuo stepwise heating of hydrous minerals is examined. By means of common-denominator three-isotope correlation diagrams, in use for 60 years, it is possible to recognize the presence of polymineralic mixtures in a step-heated mineral separate and characterize their components. This data presentation, when applied to literature studies proposing Fick's Law diffusion during in vacuo stepwise heating, shows that in actual fact these studies were based on partly retrogressed micas that were intergrown with their alteration products, probably at a scale < 20 µm so as to escape recognition during handpicking. The degassing of hydrous minerals in vacuo does not follow Fick's Law in an inert, homogeneous matrix, and instead proceeds from the structural collapse during dehydration. The data presentation discussed here quantifies the differential release of the Ar isotopes. Their release follows the structural collapse of their host phases and gives rise to remarkably well resolved patterns even in polymineralic samples.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Isotope Geology

UniBE Contributor:

Villa, Igor Maria

Subjects:

500 Science > 550 Earth sciences & geology
500 Science

ISSN:

0009-2541

Publisher:

Elsevier

Language:

English

Submitter:

Igor Maria Villa-Toscani

Date Deposited:

23 Jan 2023 10:01

Last Modified:

23 Jan 2023 23:28

Publisher DOI:

10.1016/j.chemgeo.2021.120076

Uncontrolled Keywords:

geochronology, 40Ar/39Ar dating, diffusion, retrogression reactions

BORIS DOI:

10.48350/176702

URI:

https://boris.unibe.ch/id/eprint/176702

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