Acta Oceanologica Sinica: New information on the basement rocks of the Xisha Islands

The basement properties of island reefs are an important part of the formation and evolution of coral reefs, and also an important part of geotectonics research. Studying on the composition and properties of the basement can provide an important theoretical basis for discussing the relationship between adjacent plates, tectonic characteristics, formation mechanisms, and the tectonic evolution of adjacent areas. The authors present the LA-ICP-MS zircon U-Pb ages of basaltic pyroclastic rocks from Well CK-1, Chenhang Island, Xisha Islands, South China Sea (SCS), to determine the time of magmatic activity. The Xisha micro-block may have developed on a uniform Late Jurassic metamorphic crystalline basement intruded by the Cretaceous granitic magma. There exists Precambrian crystalline basement within microblocks in the SCS. The crustal remelting of the old Precambrian basement corresponds to the rapid thinning of the South China lithosphere during the Mesozoic, which covered the imprint of the Precambrian crystalline basement in the study area. The research results are published in Acta Oceanologica Sinica“U-Pb zircon geochronology of basaltic pyroclastic rocks from the basement beneath the Xisha Islands in the northwestern South China Sea and its geological significance”.