Publication Date:
2019-09-23
Description:
To investigate the mechanisms of the offset of seawater radiogenic Nd-Hf isotope compositions from those of the upper continental crust rocks, combined Nd-Hf isotope compositions
of desert and loess samples from northern China (which integrate a wide range of lithologies and ages of continental rocks) are presented in this study. The results show significant and systematic fractionation of Hf isotopes between finegrained detritals/leachates (〈5 mm) and coarser fractions (〈75 mm) of the same samples. A small but systematic difference of Nd isotope compositions between leachates and detrital silicates is also revealed. Overall, the leaching data either plot along or slightly above the Nd-Hf seawater array, providing strong direct support that the seawater Nd-Hf isotope relationship is predominantly generated by weathering of upper continental crust. Our study supports the application of dissolved Hf
isotopes as a proxy for different modes of weathering regimes rather than for continental source provenances.
Type:
Article
,
PeerReviewed
Format:
text
Format:
text
