MacDonald, J.M. , VanderWal, J., Roberts, N.M.W., Winkelstern, I.Z., Faithfull, J.W. and Boyce, A.J. (2020) Fingerprinting fluid source in calcite veins: combining LA-ICP-MS U-Pb calcite dating with trace elements and clumped isotope palaeothermometry. EarthArXiv, (doi: 10.31223/osf.io/qsm86) (Submitted)
|
Text
222482.pdf - Submitted Version Available under License Creative Commons Attribution. 582kB |
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 distinctive patterns and shed no further light on fluid source. LA-ICP-MS U-Pb dating determined the vein calcite precipitation age – 318±30 Ma – which rule out metamorphic or magmatic fluid sources as no metamorphic or magmatic activity was occurring in the area at this time. The vein fluid source was therefore 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 |
|---|---|
| Keywords: | Geothermometry, calcite, geothermal, clumped isotopes, isotopologues, geology. |
| Status: | Submitted |
| Refereed: | No |
| Glasgow Author(s) Enlighten ID: | Boyce, Professor Adrian and Faithfull, Dr John and MacDonald, Dr John |
| 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: | University Services > Library and Collection Services > Museum and Art Gallery College of Science and Engineering > School of Geographical and Earth Sciences College of Science and Engineering > Scottish Universities Environmental Research Centre |
| Journal Name: | EarthArXiv |
| Copyright Holders: | Copyright © 2020 The Authors |
| Publisher Policy: | Reproduced under a Creative Commons License |
University Staff: Request a correction | Enlighten Editors: Update this record
Funder and Project Information
Funder and Project Information