Abstract Large and small‐medium river delta systems play distinct roles in sediment source‐to‐sink transport processes within coastal zones; however, it remains unclear how to distinguish sediment sources between these two systems. Although environmental magnetism has demonstrated potential, the specific method and underlying influencing factors remain poorly defined. We compare the magnetic properties of sediments from small (Rongjiang and Lianjiang) and medium‐sized (Hanjiang) rivers in the Hanjiang River Delta with those from large river delta systems (Yangtze and Yellow Rivers) in East Asia. Magnetic properties of bulk samples can identify the provenance of river sediments in the Hanjiang River Delta due to variations in hydrodynamic sorting and lithological composition, but they are insufficient for distinguishing sediments from small‐medium and large river delta systems. By analyzing particle‐size‐dependent magnetic properties, we found that magnetic minerals are coarser in small‐ to medium ‐ size river deltas than in large ones. Furthermore, sediments from small‐medium and large river deltas can be distinguished by analyzing magnetic property distributions across particle size fractions: small‐medium delta sediments have higher magnetic mineral content in the 16–32 μm and 32–63 μm fractions, while large delta sediments are enriched in the <16 μm fraction. This phenomenon mainly stems from differences in transport distance between large and small‐medium river delta systems. Our results not only deepen the understanding of magnetic variability mechanisms but also provide new insights into sediment provenance detection in estuarine and coastal environments influenced by river systems of varying sizes.
Wang et al. (Sun,) studied this question.