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Geochemistry of Vein Calcites Hosted in the Troodos Pillow Lavas and Their Implications for the Timing and Physicochemical Environment of Fracturing, Fluid Circulation, and Vein Mineral Growth

Quandt, D.; Micheuz, P.; Kurz, W.; Kluge, T.; Boch, R.; Hippler, D.; Krenn, K.; Hauzenberger, C.A.

Abstract (englisch):
Calcite veins hosted in pillow lavas of the Late Cretaceous Troodos suprasubduction zone ophiolite provide insights into the timing and physicochemical environment of postmagmatic fracturing and fluid circulation through oceanic crust. This study presents rare earth element and yttrium (REE+Y) concentrations, δ13C, δ18O, 87Sr/86Sr, and clumped isotopic (Δ47) compositions of vein calcites in order to investigate their fluid sources, formation temperatures, and precipitation ages. These geochemical data are combined with microtextural analyses. Intersections of 87Sr/86Sr ratios of vein calcites with the Sr isotope seawater curve suggest two distinct calcite veining phases. Major calcite veining within an interval of ~10 Myr after crust formation is characterized by microtextures that point to extensional fracturing related to crack and sealing, host rock brecciation, and advective fluid flow. These vein calcites show REE+Y characteristics, 87Sr/86Sr ratios, and clumped isotopic compositions indicative of precipitation from seawater at <50 °C. Extended fluid residence times intensified fluid‐rock interactions and lowered Y/Ho ratios of some blocky vein calcites, whereas crack and sealing resulted in pristine seawater signatures. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000117990
Veröffentlicht am 01.04.2020
Originalveröffentlichung
DOI: 10.1029/2019GC008369
Scopus
Zitationen: 2
Web of Science
Zitationen: 2
Dimensions
Zitationen: 3
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 12.2019
Sprache Englisch
Identifikator ISSN: 1525-2027, 1525-2027
KITopen-ID: 1000117990
Erschienen in Geochemistry, geophysics, geosystems
Verlag Wiley
Band 20
Heft 12
Seiten 5913–5938
Vorab online veröffentlicht am 10.12.2019
Nachgewiesen in Scopus
Web of Science
Dimensions
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