“Petit Spot” Rejuvenated Volcanism Superimposed on Plume‐Derived Samoan Shield Volcanoes: Evidence From a 645‐m Drill Core From Tutuila Island, American Samoa

We collected whole rock radiogenic isotopic (Sr, Nd, and Pb) compositions and whole rock major and trace element concentrations on lavas from a 645-m drill core from Tutuila Island, America Samoa. The goal of the study was to identify patterns in the geochemical evolution of the volcano, and capture the onset of rejuvenated volcanism. Following the termination of shield stage volcanism at 1.17 Ma, a 1.15 million-year-long volcanic hiatus lasted until the appearance of rejuvenated volcanism at 24.3 Ma.

本研究采集了美属萨摩亚图图伊拉岛一段645米钻探岩心中的熔岩样品，对其全岩放射成因同位素（Sr、Nd及Pb）组成以及全岩主量、微量元素含量进行了测试分析。本研究旨在识别该火山的地球化学演化规律，并捕捉复活型火山作用（rejuvenated volcanism）的起始特征。在1.17 Ma盾状火山作用阶段结束后，存在一段长达115万年的火山喷发间断期，直至24.3 Ma复活型火山作用出现。