U–Pb dating of calcite in ancient carbonates for age estimates of syn- to post-depositional processes: a case study from the upper Ediacaran strata of Finnmark, Arctic Norway

Meinhold, Guido; Roberts, Nick M.W.; Arslan, Arzu; Jensen, Sören; Ebbestad, Jan Ove R.; Högström, Anette E. S.; Høyberget, Magne; Agić, Heda; Palacios, Teodoro; Taylor, Wendy L.. 2020 U–Pb dating of calcite in ancient carbonates for age estimates of syn- to post-depositional processes: a case study from the upper Ediacaran strata of Finnmark, Arctic Norway. Geological Magazine, 157 (8). 1367-1372. https://doi.org/10.1017/S0016756820000564

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Official URL: http://dx.doi.org/10.1017/S0016756820000564

Abstract/Summary

Results of in situ U–Pb dating of calcite spherulites, cone-in-cone (CIC) calcite and calcite fibres from a calcareous concretion of the upper Ediacaran of Finnmark, Arctic Norway, are reported. Calcite spherulites from the innermost layers of the concretion yielded a lower intercept age of 563 ± 70 Ma, which, although imprecise, is within uncertainty of the age of sedimentation based on fossil assemblages. Non-deformed CIC calcite from the bottom part of the concretion yielded an age of 475 ± 25 Ma, which is interpreted as the age of CIC calcite formation during a period of fluid overpressure induced during burial of the sediments. Deformed CIC calcite from the top part of the concretion yielded an age of 418 ± 23 Ma, which overlaps with a known Caledonian tectono-metamorphic event, and indicates a potential post-depositional overprint at this time. Calcite fibres that grew in small fissures along spherulite rims, which are interpreted as a recrystallization feature during deformation and formation of a cleavage, gave an imprecise age of 486 ± 161 Ma. Our results show that U–Pb dating of calcite can provide age constraints for ancient carbonates and syn- to post-depositional processes that operated during burial and metamorphic overprinting.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1017/S0016756820000564
ISSN:	0016-7568
Date made live:	02 Dec 2020 11:43 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/529073

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1017/S0016756820000564

ISSN:

0016-7568

Date made live:

02 Dec 2020 11:43 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/529073