Fingerprinting fluid source in calcite veins: combining LA-ICP-MS U-Pb calcite dating with trace elements and clumped isotope palaeothermometry

MacDonald, J.M. , VanderWal, J., Roberts, N.M.W., Winkelstern, I.Z., Faithfull, J.W. and Boyce, A.J. (2024) Fingerprinting fluid source in calcite veins: combining LA-ICP-MS U-Pb calcite dating with trace elements and clumped isotope palaeothermometry. Tektonika, 2(1), pp. 27-39.

[img] Text
222482.pdf - Published Version
Available under License Creative Commons Attribution.

1MB

Publisher's URL: https://tektonika.online/index.php/home/article/view/2

Abstract

Application of geochemical proxies to vein minerals - particularly calcite - can fingerprint the source of fluids controlling various important geological processes from seismicity to geothermal systems. Determining fluid source, e.g. meteoric, marine, magmatic or metamorphic waters, can be challenging when using only trace elements and stable isotopes as different fluids can have overlapping geochemical characteristics, such as δ18O. In this contribution we show that by combining the recently developed LA-ICP-MS U-Pb calcite geochronometer with stable isotopes (including clumped isotope palaeothermometry) and trace element analysis, the fluid source of veins can be more readily determined. Calcite veins hosted in the Devonian Montrose Volcanic Formation at Lunan Bay in the Midland Valley Terrane of Central Scotland were used as a case study. δD values of fluid inclusions in the calcite, and parent fluid δ18O values reconstructed from clumped isotope palaeothermometry, gave values which could represent a range of fluid sources: metamorphic or magmatic fluids, or surface waters which had undergone much fluid-rock interaction. Trace elements showed no particularly distinctive patterns. LA-ICP-MS U-Pb dating determined the vein calcite precipitation age – 318±30 Ma – indicating a metamorphic or magmatic fluid source was unlikely as there was no metamorphic or magmatic activity was occurring in the area at this time. The vein fluid source was therefore interpreted to be a surface water (meteoric based on paleogeographic reconstruction) which had undergone significant water-rock interaction. This study highlights the importance of combining the recently developed LA-ICP-MS U-Pb calcite geochronometer with stable isotopes and trace elements to help determine fluid sources of veins, and indeed any geological feature where calcite precipitated from a fluid that may have resided in the crust for a period of time (e.g. fault precipitates or cements).

Item Type:Articles
Additional Information:J. VanderWal received funding from Dalhousie University’s Shell Educational Learning Fund (SELF) and the Society of Economic Geologists Canada Foundation (SEGCF) undergraduate research fund. Fieldwork was part-funded by Research Incentive Grant 70316 from the Carnegie Trust for the Universities of Scotland to J. M. MacDonald and J. W. Faithfull.
Keywords:geology, trace elements, geochemistry, geochronology, LA-ICP-MS, calcite.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Faithfull, Dr John and MacDonald, Dr John and Boyce, Professor Adrian
Creator Roles:
MacDonald, J.Conceptualization, Methodology, Funding acquisition, Supervision, Writing – original draft, Investigation, Data curation, Visualization
Faithfull, J.Conceptualization, Supervision, Writing – review and editing, Investigation
Boyce, A.Methodology, Writing – review and editing, Investigation
Authors: MacDonald, J.M., VanderWal, J., Roberts, N.M.W., Winkelstern, I.Z., Faithfull, J.W., and Boyce, A.J.
Subjects:Q Science > QD Chemistry
Q Science > QE Geology
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
College of Science and Engineering > Scottish Universities Environmental Research Centre
University Services > Library and Collection Services > Museum and Art Gallery
Journal Name:Tektonika
Publisher:University of Aberdeen
ISSN:2976-548X
ISSN (Online):2976-548X
Published Online:05 February 2024
Copyright Holders:Copyright © 2024 The Author(s)
First Published:First published in Tektonika 2(1):27-39
Publisher Policy:Reproduced under a Creative Commons license

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
173286Clumped isotopes in calcite: a new method for tracking fluid flow in lavas and its implications for geothermal energy generationJohn MacDonaldThe Carnegie Trust for the Universities of Scotland (CARNEGTR)70316GES - Earth Sciences