Geochemical analyses of heavy minerals (chrome spinel, zircon) from the Puxi River section, Middle Ordovician (Yichang, Hubei, China)

This comprehensive dataset presents detailed mineralogical observations, including electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), of chrome spinel and zircon grains recovered from limestone of the Middle Ordovician Kuniutan Formation at the Puxi River section in Yichang, Hubei Province, China. The dataset also encompasses U-Pb isotopic data obtained via secondary ion mass spectrometry (SIMS) analyses of zircon crystals. These data enable us to constrain the volcanic provenance of both zircon and chrome spinel. More importantly, they provide novel insights into the use of volcanic heavy minerals dispersed within limestone as a powerful proxy for reconstructing ancient volcanic activity, particularly episodes associated with mafic–ultramafic magmatism in the deep time. This work highlights the significant potential of volcanic heavy minerals in tracing cryptic volcanic events hosted in carbonate successions and establishes diagnostic criteria for identifying dispersed volcanic ash layers in limestones.