No abstract

Citation for published item:hellingerD wthieu nd fouhezD tulien nd qillrdetD t¡ er¢ ome nd pureD vetiti nd woureuD tulien @PHIUA 9ring wethering regimes using the lithium isotope omposition of detritl sedimentsF9D qeologyFD RS @SAF ppF RIIERIRF Further information on publisher's website: httpsXGGdoiForgGIHFIIQHGqQVTUIFI Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT 9Lithium (Li) isotopes are a promising tracer of chemical weathering processes for 10 both modern and ancient times. In order to improve the use of Li isotopes in the 11 sedimentary record, here we calibrate the relationship between weathering intensity and 12 detrital Li isotope composition ( 7 Li) using the fine fraction of modern large river 13 sediments. By using independent estimates for sediment provenance to calculate the Li 14 isotope signature of the rock from which the sediments derive through weathering, we 15show that source rock variability (in particular the relative contribution of sedimentary vs. 16 igneous rocks) must be corrected for before using Li isotopes as a weathering proxy. We 17 also show that for rivers draining mountain ranges, the contribution of particles derived 18 from sedimentary rocks to river sediments is correlated to their Li/Al ratio, making it 19 possible to use Li contents to estimate the average source rock composition. Once 20 corrected for bedrock variability, the Li isotope signature defines a negative relationship 21 with the weathering intensity (ratio between silicate weathering rate and total denudation 22 Page 2 of 17 rate) with highest Li isotope fractionation for the highest weathering intensity. 23Altogether, we propose a set of new relationships between weathering, erosion, 24 provenance and Li isotopes that can be used to quantify present-day and paleo-25 weathering using detrital sediment.