Collaborative Research: Towards quantifying eruptive timing and volcanic accretion on the Southern East Pacific Rise

合作研究：量化东南太平洋隆起的喷发时间和火山增生

• 批准号: 2128108
• 负责人: Julie Bowles
• 金额: $ 27.65万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2128108&HistoricalAwards=false
• 关键词: Collaborative; Research; Towards; quantifying; eruptive

Collaborative Research: Eruptive timing and volcanic accretion on the Southern East Pacific RiseSeventy percent of Earth’s surface is covered by ocean crust created by volcanoes at underwater mid-ocean ridges. It is important to accurately describe the size, shape, and frequency of submarine lava flows to understand how mid-ocean ridge volcanic systems work. A recent National Academies report identifies description of eruptive sizes and frequencies as one of the outstanding grand challenges in volcano science. However, distinguishing and accurately dating individual submarine lava flows remains challenging due to inadequate dating techniques, as well as considerable technical challenges associated with making observations and collecting samples from the seafloor. This project takes multiple approaches to measuring eruptive timing on the Southern East Pacific Rise (a mid-ocean ridge in the south Pacific). Data from self-driving underwater vehicles (AUV-autonomous underwater vehicle) will be combined with submersible observations and sample collection. Sample chemistry and magnetic signals help determine age and eruption frequency of surface flows, while the AUV data provide high-resolution mapping of the sea floor and additional information related to sub-surface lava flow distributions. The results will be combined into a model that can be and applied to other mid-ocean ridge settings. The proposed work will provide a comparison to the well-studied 9°N section of the northern East Pacific Rise, expanding the small number of intensively-studied ridge segments.The size, shape, and eruptive frequency of submarine lava flows are important first-order variables in our understanding of many mid-ocean ridge processes, including volcanic construction; magma recharge, flux, and storage; and the stability of hydrothermal systems and biological communities. A recent National Academies report identifies the quantification of eruptive sizes and frequencies as integral to one of the outstanding grand challenges in volcano science. However, distinguishing and accurately dating individual submarine flows in the geological record remains challenging due to inadequate radiometric techniques, as well as the considerable technical challenges associated with making observations and collecting samples from the seafloor. Further, for a process that is episodic, there is no commonly-accepted statistical framework for reporting or interpreting eruptive intervals. While considerable effort has gone into documenting eruptive history at 9°N on EPR and at Axial seamount on the Juan de Fuca Ridge, constraining a spatially and temporally variable global system requires significantly more data, and perhaps new approaches. The proposed work takes an integrated approach to quantifying eruptive timing on the Southern East Pacific Rise by combining AUV (autonomous underwater vehicle) mapping with HOV (human occupied vehicle) observations and sample collection. Near-bottom sidescan and bathymetric data will guide sampling locations and provide important interpretive context, as well as the possibility of calculating flow volumes. Geochemical data will be combined with temporal constraints provided by geomagnetic paleointensity to define eruptive clusters. Near-bottom magnetic anomaly data will be used to link the surface paleomagnetic data with a depth-integrated signal and provide important constraints on 3D statistical models of flow distributions, which are also constrained by estimates of layer 2A thickness from existing seismic reflection data. Combined, these methods will enable identification of flow units, quantifying eruptive frequency, and assessing accretionary processes. The resulting statistical model can be tested against and applied to other mid-ocean ridge settings. Further, the proposed work will provide a point of contrast to the well-studied 9°N segment and expand the small number of intensively-studied ridge segments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

合作研究：东南太平洋隆起的火山爆发时间和火山增生地球表面的百分之七十被海底中脊火山产生的海洋地壳覆盖。准确描述海底熔岩流的大小、形状和频率对于了解大洋中脊火山系统的工作方式至关重要。美国国家科学院最近的一份报告指出，对火山喷发规模和频率的描述是火山科学面临的重大挑战之一。然而，由于测年技术不足，以及与从海底进行观测和收集样本有关的相当大的技术挑战，区分和准确测定个别海底熔岩流的年代仍然具有挑战性。 该项目采用多种方法来测量东南太平洋海隆（南太平洋的一个洋中脊）的喷发时间。来自自动驾驶水下航行器（AUV-自主水下航行器）的数据将与潜水观测和样本收集相结合。 样品的化学成分和磁信号有助于确定地表熔岩流的年龄和喷发频率，而自动潜航器数据则提供了海底高分辨率绘图和与地表下熔岩流分布有关的其他信息。 这些结果将被合并成一个模型，可以应用于其他洋中脊环境。拟议的工作将提供一个比较研究的北方东太平洋海隆的9°N部分，扩大了少数深入研究的海脊段，海底熔岩流的大小，形状和喷发频率是重要的一阶变量，在我们的许多洋中脊过程的理解，包括火山建设，岩浆补给，流量和存储;以及热液系统和生物群落的稳定性。美国国家科学院最近的一份报告指出，火山喷发规模和频率的量化是火山科学面临的重大挑战之一。然而，由于辐射测量技术不足，以及在进行观测和从海底收集样本方面存在相当大的技术挑战，在地质记录中区分个别海底水流并准确确定其年代仍然具有挑战性。此外，对于偶发性过程，没有普遍接受的统计框架来报告或解释喷发间隔。虽然在记录EPR上9°N和Juan de Fuca海岭上Axial海山的喷发历史方面已经做了相当大的努力，但限制一个时空可变的全球系统需要更多的数据，也许还需要新的方法。拟议的工作采取综合的方法来量化东南太平洋隆起的喷发时间，结合AUV（自主水下航行器）映射HOV（载人潜水器）的观测和样本收集。近底侧扫和测深数据将指导取样地点，提供重要的解释背景，并有可能计算流量。地球化学数据将与地磁古强度提供的时间限制相结合，以确定喷发群。近底磁异常数据将用于将地表古地磁数据与深度积分信号联系起来，并对三维流量分布统计模型提供重要的制约，而流量分布统计模型也受到根据现有地震反射数据对2A层厚度估计的制约。结合起来，这些方法将能够识别流动单元，量化喷发频率，并评估增生过程。由此产生的统计模型可以对照其他洋中脊环境进行测试和应用。此外，拟议的工作将提供一个点的对比，以充分研究的9°N部分，并扩大了少数深入研究的山脊段。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。