Evaluation of multiple weathering indices of fine-grained river sediments as climate proxies in subtropical and tropical South China

•The CIA of river-borne clay in South China record the present climates.•Mineral sorting and recycling on weathering indices can’t be ignored for fine silt.•Clay minerals in rivers from South China are influenced by parent rocks. Geochemical and mineral compositions of river sediments are crucial for the understanding of continental weathering and climate changes in the past. Although fined-grained sediments were generally considered as reliable archives of past weathering history, the effectiveness of weathering indices and potential interference factors were rarely discussed seriously. This paper chooses modern river basins in subtropical–tropical South China to evaluate the effectiveness of multiple weathering indices of fine-grained fractions (