Degassing During a Seafloor Eruption along the Mid-Ocean Ridge: Helium, Argon and Carbon Isotopes in Basalts from the East Pacific Rise Integrated Study Site

几乎所有的大洋中脊玄武岩岩浆在通过洋壳上升时都会失去气体，因为它们被二氧化碳饱和或过饱和。未知数量的二氧化碳通过水热系统排出，并通过生化反应被栖息在水热系统中的有机体利用。这项研究测量了1991-1992年和2005-2006年在东太平洋隆起的Ridge 2000综合研究地点喷发的玄武岩熔岩气泡中的惰性气体(Ar和He)和二氧化碳浓度。这些气体的浓度和同位素组成提供了基本信息，可用于确定大洋中脊上熔岩的脱气量，并提供对洋壳中岩浆演化的洞察。对单个熔岩流长度的样品进行分析，为研究大洋中脊的岩浆补给提供了前所未有的机会，量化了已发生的喷发前和同时喷发的脱气量，并评估了地球内部的碳被并入热液流体并最终进入海底生态系统的程度。这项工作的更广泛影响包括支持俄勒冈州立大学的一个新的惰性气体设施和培训学生。

Virtually all mid-ocean ridge basalt magmas lose gas as they rise through the ocean crust because they are saturated or oversaturated with carbon dioxide. An unknown amount of the CO2 that is lost is vented through hydrothermal systems and used by organisms inhabiting them via biochemical reactions. This research measures noble gas (Argon and Helium) and CO2 concentrations trapped in bubbles of basaltic lavas erupted from 1991-1992 and 2005-2006 at the RIDGE 2000 Integrated Study Site on the East Pacific Rise. The concentration and isotopic composition of these gases provide fundamental information that can be used to determine the amount of lava degassing on mid-ocean ridges and provide insights into the evolution of magmas in the ocean crust. Analyses of samples along the length of individual lava flows offer an unprecedented opportunity to study magma recharge at a mid-ocean ridge, quantify the amount of pre-eruptive and syn-eruptive degassing that has occurred, and evaluate the extent to which carbon from Earth's interior is incorporated into hydrothermal fluids and ultimately into seafloor ecosystems. Broader impacts of the work include support of a new noble gas facility at Oregon State University and trains students.