Effect of Melt Supply on MORB Compositions at Local and Regional Scales

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。海底大洋中脊是地球上火山活动最活跃的地方。从它们喷发出来的熔岩覆盖了大约三分之二的地球表面。这座火山是地球内部热量和物质的主要出口，在海洋化学和海底生命生态方面发挥着重要作用。这项研究评估了导致喷发熔岩成分变化的过程，这些变化发生在区域(100-1000公里)到地方(10-100公里)的尺度上，并持续了几十年到几千年。利用数据挖掘技术、全球海底火山岩成分数据库和统计分析，这项工作试图确定岩浆分异、岩浆混合和地幔来源成分的耦合变化。对时间尺度的限制将根据已公布的放射性U系列日期以及将在关键岩石样本上确定的新的放射性日期来确定。工作重点放在研究地点，在这些地点，熔体供应最近在一系列火山条件下在时间或空间上发生了变化，并且已经掌握了岩石样本和成分数据。这项工作的重要性在于，它揭示了物质和热量从地球内部移动到表面的规模和时空变异性，以及随之而来的地壳结构和深海环境变化的影响。这项工作的更广泛影响包括国际合作、学生培训和对EPSCoR州(夏威夷)的机构的支持。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Submarine mid-ocean ridges are the most volcanically active places on the planet. Lavas erupted from them cover roughly 2/3 of the Earth's surface. This volcanism is a major outlet for heat and matter in Earth's interior and plays a significant role in ocean chemistry and the ecology of the seafloor life. This research evaluates processes responsible for variations in erupted lava compositions that occur at the regional (100-1000 km) to local (10-100 km) length scales and that operate over decades to millennia. Using data mining techniques, global databases of seafloor volcanic rock compositions, and statistical analysis, the work seeks to determine coupled variations in magma differentiation, magma mixing, and mantle source composition. Constraints on timescales will be determined from published radiogenic U-series dates as well as new radiogenic dates that will be determined on key rock samples. Work focuses on study sites where melt supply has recently varied in time or space over a range of volcanic conditions and where rock samples and compositional data are already in hand. The importance of the work is that it sheds light on the magnitude and temporal-spatial variability of movement of material and heat from Earth's interior to its surface, with attendant implications for how Earth's crust is constructed and environmental change in the deep oceans. Broader impacts of the work include international collaboration, student training, and support of an institution in an EPSCoR state (Hawaii).