Boron isotopes trace an increase in subduction-driven recycling of fluid-mobile elements in the Neoarchean
(2025) In Geochimica et Cosmochimica Acta 408. p.1-11- Abstract
The deep recycling of surface material into Earth’s mantle is an integral process governing global water and fluid-mobile element cycles. This recycling is largely predicated on subduction operating efficiently, which may not apply for the first two billion years of Earth’s history. Tracing the initiation and evolution of the modern deep fluid-mobile element cycle requires determining when the mantle first became modified by subducted surface-derived materials on a global scale. The B isotope system provides a unique geochemical parameter to test for early signatures of such recycling, given that B is enriched and isotopically fractionated at Earth’s surface, depleted in the mantle, and mobilized by fluids and fluid-rock interaction. In... (More)
The deep recycling of surface material into Earth’s mantle is an integral process governing global water and fluid-mobile element cycles. This recycling is largely predicated on subduction operating efficiently, which may not apply for the first two billion years of Earth’s history. Tracing the initiation and evolution of the modern deep fluid-mobile element cycle requires determining when the mantle first became modified by subducted surface-derived materials on a global scale. The B isotope system provides a unique geochemical parameter to test for early signatures of such recycling, given that B is enriched and isotopically fractionated at Earth’s surface, depleted in the mantle, and mobilized by fluids and fluid-rock interaction. In this study, B isotopes of granitoids from seven Archean cratons are analyzed to trace the early signatures of recycling of surface-altered materials. When filtered for alteration and (post-)magmatic B modification, the B isotope compositions of the sample set show substantial variation. The range exhibited by sanukitoids (−8.9 ‰ to −1.6 ‰, mean: −4.7 ‰, n = 5) overlaps with other granitoids (−15.8 ‰ to +8.0 ‰, mean: −8.6 ‰, n = 30), but the average B isotope composition of sanukitoids is higher than other granitoids. The granitoids reveal a temporal diversification towards, on average, higher11B/10B values from the Neoarchean onward. The heavier B isotope values reflect the recycling of surface-derived B into the melt source along a geotherm that was cold enough to prevent total loss of B through dehydration reactions, consistent with a cold-subduction geotherm. The B data thus indicate that the subduction-driven recycling of surface-derived materials into the mantle became more prevalent since the Neoarchean, marking this era as the likely starting point for the modern deep fluid-mobile element and water cycle.
(Less)
- author
- Goumans, Jeroen
; Smit, Matthijs A.
; Musiyachenko, Kira A.
; Rasbury, E. Troy
; Bleeker, Wouter
; Caton, Summer
; Halla, Jaana
; Hoffmann, Jörg Elis
; Kooijman, Ellen
; Mezger, Klaus
; Pandey, Om Prakash
LU
; Ravindran, Arathy
and Scherstén, Anders
LU
(Less) - organization
- publishing date
- 2025-11-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Archean granitoids, B isotopes, Deep water cycle, Fluid-mobile elements, Recycling
- in
- Geochimica et Cosmochimica Acta
- volume
- 408
- pages
- 11 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:105017585475
- ISSN
- 0016-7037
- DOI
- 10.1016/j.gca.2025.09.021
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/
- id
- 27b61f04-162e-46b4-a4c9-167204741cf8
- date added to LUP
- 2025-11-18 15:48:06
- date last changed
- 2025-11-19 13:07:50
@article{27b61f04-162e-46b4-a4c9-167204741cf8,
abstract = {{<p>The deep recycling of surface material into Earth’s mantle is an integral process governing global water and fluid-mobile element cycles. This recycling is largely predicated on subduction operating efficiently, which may not apply for the first two billion years of Earth’s history. Tracing the initiation and evolution of the modern deep fluid-mobile element cycle requires determining when the mantle first became modified by subducted surface-derived materials on a global scale. The B isotope system provides a unique geochemical parameter to test for early signatures of such recycling, given that B is enriched and isotopically fractionated at Earth’s surface, depleted in the mantle, and mobilized by fluids and fluid-rock interaction. In this study, B isotopes of granitoids from seven Archean cratons are analyzed to trace the early signatures of recycling of surface-altered materials. When filtered for alteration and (post-)magmatic B modification, the B isotope compositions of the sample set show substantial variation. The range exhibited by sanukitoids (−8.9 ‰ to −1.6 ‰, mean: −4.7 ‰, n = 5) overlaps with other granitoids (−15.8 ‰ to +8.0 ‰, mean: −8.6 ‰, n = 30), but the average B isotope composition of sanukitoids is higher than other granitoids. The granitoids reveal a temporal diversification towards, on average, higher<sup>11</sup>B/<sup>10</sup>B values from the Neoarchean onward. The heavier B isotope values reflect the recycling of surface-derived B into the melt source along a geotherm that was cold enough to prevent total loss of B through dehydration reactions, consistent with a cold-subduction geotherm. The B data thus indicate that the subduction-driven recycling of surface-derived materials into the mantle became more prevalent since the Neoarchean, marking this era as the likely starting point for the modern deep fluid-mobile element and water cycle.</p>}},
author = {{Goumans, Jeroen and Smit, Matthijs A. and Musiyachenko, Kira A. and Rasbury, E. Troy and Bleeker, Wouter and Caton, Summer and Halla, Jaana and Hoffmann, Jörg Elis and Kooijman, Ellen and Mezger, Klaus and Pandey, Om Prakash and Ravindran, Arathy and Scherstén, Anders}},
issn = {{0016-7037}},
keywords = {{Archean granitoids; B isotopes; Deep water cycle; Fluid-mobile elements; Recycling}},
language = {{eng}},
month = {{11}},
pages = {{1--11}},
publisher = {{Elsevier}},
series = {{Geochimica et Cosmochimica Acta}},
title = {{Boron isotopes trace an increase in subduction-driven recycling of fluid-mobile elements in the Neoarchean}},
url = {{http://dx.doi.org/10.1016/j.gca.2025.09.021}},
doi = {{10.1016/j.gca.2025.09.021}},
volume = {{408}},
year = {{2025}},
}