Data report: major and trace element and Sr-Nd-Pb-Hf isotope composition of three granite clasts from Hole U1501D in the South China Sea (IODP Expedition 367/368/368X)

During International Ocean Discovery Program Expeditions 367/368/368X, Hole U1501D was cored on the continental shelf (2846 meters below sea level) in the northern South China Sea (SCS). In Hole U1501D, sediments were recovered from 433.5 to 644.3 meters below seafloor (mbsf) and the acoustic basement was penetrated at 598.91 mbsf. The acoustic basement is a stratigraphic boundary at which late Eocene Cenozoic sediments likely unconformably overlay heterolithic Mesozoic sandstones that are intercalated with rare siltstones and subordinate conglomerate with pebble- and cobble-sized igneous clasts of proximal provenance. Here, we present major and trace elements and Sr-Nd-Pb-Hf isotope data of a fine-grained granite pebble, a medium-grained granite cobble, and a porphyritic volcanic pebble. The data show that these clasts are relics of the Mesozoic subduction-related magmatism that was active along the southeast Asian margin prior to the Cenozoic rifting. The Pb isotope composition of the clasts partially overlaps with the enriched Cenozoic mid-ocean-ridge basalt type and intraplate basalts of the SCS. However, the clasts are distinct from the Cenozoic basalt volcanism in Sr-Nd-Hf isotope space. Thus, Sr-Nd-Hf isotope systematics of the Cenozoic basalts might be useful in detecting traces of crustal contamination in the earliest rift basalts of the SCS that may have erupted through the Mesozoic continental basement.