eprintid: 10206055 rev_number: 6 eprint_status: archive userid: 699 dir: disk0/10/20/60/55 datestamp: 2025-03-14 12:18:14 lastmod: 2025-03-14 12:18:14 status_changed: 2025-03-14 12:18:14 type: article metadata_visibility: show sword_depositor: 699 creators_name: Liu, Xianyi creators_name: Krause, Alexander J creators_name: Wilson, David J creators_name: Fraser, Wesley T creators_name: Joachimski, Michael M creators_name: Brand, Uwe creators_name: Stigall, Alycia L creators_name: Qie, Wenkun creators_name: Chen, Bo creators_name: Yang, Xiangrong creators_name: Pogge von Strandmann, Philip AE title: Lithium isotope evidence shows Devonian afforestation may have significantly altered the global silicate weathering regime ispublished: inpress divisions: UCL divisions: B04 divisions: C06 divisions: F57 keywords: Li isotopes, Devonian, Biosphere, Weathering, Carbonate diagenesis note: © 2025 The Author(s). Published by Elsevier Ltd. under a Creative Commons license (http://creativecommons.org/licenses/by/4.0/). abstract: The Devonian Period (∼359–419 Ma) documents significant environmental changes and marine species turnover, but whether these changes were linked to terrestrial weathering remains unknown. Here, we use lithium isotopes in brachiopods and bulk marine carbonates (δ7Licarb) from the Devonian Period to investigate changes in silicate weathering, which represents the primary long-term atmospheric CO2 sink. A rise of ∼ 10 ‰ in δ7Licarb values (from ∼ 8 ‰ to ∼ 18 ‰) is observed across the Mid-Devonian (∼378–385 Ma), suggesting a major change in the seawater Li cycle. We attribute the rise in δ7Licarb values to an increase in the dissolved riverine Li flux and δ7Liriver values, which likely arose from increases in both weathering intensity and regolith thickness, related to the expansion of deep-rooted plants. However, the presence of such terrestrial ecosystems would also have restricted the continuous weathering of silicate rocks. In order to maintain high δ7Liseawater values in the Late Devonian, we propose that repeated cycles of destruction and regeneration of terrestrial forest ecosystems could have occurred, which would have prevented a supply-limited weathering regime from being permanently established. Such a process would potentially have caused oscillations in marine nutrient availability and redox conditions, thereby contributing to prolonged marine biodiversity loss during the Late Devonian. date: 2025-03-01 date_type: published publisher: Elsevier BV official_url: https://doi.org/10.1016/j.gca.2025.02.036 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2367021 doi: 10.1016/j.gca.2025.02.036 lyricists_name: Wilson, David lyricists_id: DJWIL75 actors_name: Wilson, David actors_id: DJWIL75 actors_role: owner full_text_status: public publication: Geochimica et Cosmochimica Acta citation: Liu, Xianyi; Krause, Alexander J; Wilson, David J; Fraser, Wesley T; Joachimski, Michael M; Brand, Uwe; Stigall, Alycia L; ... Pogge von Strandmann, Philip AE; + view all <#> Liu, Xianyi; Krause, Alexander J; Wilson, David J; Fraser, Wesley T; Joachimski, Michael M; Brand, Uwe; Stigall, Alycia L; Qie, Wenkun; Chen, Bo; Yang, Xiangrong; Pogge von Strandmann, Philip AE; - view fewer <#> (2025) Lithium isotope evidence shows Devonian afforestation may have significantly altered the global silicate weathering regime. Geochimica et Cosmochimica Acta 10.1016/j.gca.2025.02.036 <https://doi.org/10.1016/j.gca.2025.02.036>. (In press). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10206055/1/Liu%20et%20al%202025%20GCA%20Devonian%20%2B%20supp.pdf