Volcanic geology and phreato-magmatic eruption of Naozhou Island in Guangdong

Naozhou Island is located in the eastern sea of the Leizhou Peninsula, and the most characteristic form of volcanic eruption on the island is the phreato-magmatic eruption that occurred in the Nayan Bay, southeast of the island, which is a window to unraveling the history, environment, and process of volcanic eruption series on Naozhou Island. In this paper, we analyze and discuss the history of volcanic activity and the characteristics of phreato-magmatic eruption and trace the source of its base surge deposits, starting from the volcanic geology of Naozhou Island, the particle size analysis of base surge deposits from phreato-magmatic eruption, the stable isotope analysis of the organic matter, and the electron spin resonance (ESR) dating methods. The results show that the initial construction of the island was completed by a strong magma overflow in the Early Pleistocene, after which Naozhou Island ceased to receive deposits above sea level; two episodes of small to medium scale volcanic events occurred in the Middle Pleistocene, a phreato-magmatic eruption of about 588ka before present and a magma overflow of about 448ka before present. A weakly explosive eruption may have occurred in the Late Pleistocene in the vicinity of Cunliang Bay, and the volcanic activity on the island has been over since Naozhou Island was established. The island's volcanic activity has ended since then.