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In situ dating and investigation of remarkably depleted –27.3‰ SMOW “Slushball” Earth zircons

Bindeman, I. and Vazquez, J. and Schmitt, A. and Eiler, J. and Serebryakov, N. and Evans, D. (2011) In situ dating and investigation of remarkably depleted –27.3‰ SMOW “Slushball” Earth zircons. Mineralogical Magazine, 75 (3). p. 530. ISSN 0026-461X. https://resolver.caltech.edu/CaltechAUTHORS:20130806-112431702

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Abstract

Paleoproterozoic amphibolites and gneisses - that are remarkably depleted in ^(18)O are found in the Belomorian Belt in Karelia, Russia [1,2]. We mapped their extent to exceed 200x20km and affect metamorphosed mafic intrusions (est. ~2.4 Ga intrusion age) and host 2.6Ga gneisses found in this 1.9 Ga collisional belt. δ^(18)O values of –7 to –27.3‰ characterize minerals and rocks from several of these localities; some of these rocks are also remarkably depleted with respect to δD (-212 to –235‰ amphiboles). All have typical terrestrial Δ^(17)O values of 0‰. Based on previous paleogeographic reconstructions, we attribute the origin of these exotic O and H isotope compositions to the hydrothermal alteration associated with subglacial rifting during the Paleoproterozoic panglobal ice ages, but discuss additional possibilities: extremely low-δ^(18)O Paleo- proterozoic sea water, and excursion of Karelia to polar latitudes. Given that at high-T hydrothermal exchange equilibrium Δ^(18)O(rockwater) is close to zero, but water-rock interaction is rarely 100% efficient, the lowest measured δ^(18)O value in silicates likely gives the upper δ^(18)O bound for the altering meteoric fluid; we thus continues our quest to find the lowest δ^(18)O material such as a mineral assemblage or a tiny zircon fragment that would provide record of δ^(18)Owater.


Item Type:Article
Related URLs:
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http://minmag.geoscienceworld.org/content/75/3.tocPublisherIssue Table of Contents
http://goldschmidt.info/2011/abstracts/view.htmlOtherConference Website Abstracts
Additional Information:© 2011 by the Mineralogical Society of Great Britain and Ireland. Open Access Article. Published online 1 August 2011.
Issue or Number:3
Record Number:CaltechAUTHORS:20130806-112431702
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130806-112431702
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39784
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Aug 2013 18:49
Last Modified:03 Oct 2019 05:10

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