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: 2128091
• 负责人: Virginia Dorsey Wanless
• 金额: $ 27.36万
• 依托单位: Boise State University
• 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=2128091&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：东南太平洋隆起的喷发时间和火山增生地球表面的百分之七十被水下洋中脊火山形成的洋壳覆盖，准确描述海底熔岩流的大小、形状和频率非常重要。了解洋中脊火山系统如何运作然而，美国国家科学院最近的一份报告将喷发规模和频率的描述视为火山科学的重大挑战之一。由于测年技术不足，以及从海底进行观测和收集样本相关的相当大的技术挑战，区分和准确测定单个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隆起的喷发时间。来自自动驾驶水下航行器（AUV-自主水下航行器）的数据将与潜水器观测和样本收集相结合，有助于确定表面流的年龄和喷发频率。 AUV数据提供了海底的高分辨率测绘以及与地下熔岩流分布相关的附加信息，其结果将被合并到一个可以应用于其他洋中脊设置的模型中。与经过深入研究的东太平洋海隆北部 9°N 部分进行比较，扩大了少数经过深入研究的山脊部分。海底熔岩流的大小、形状和喷发频率是我们理解中重要的一阶变量的许多洋中脊过程，包括火山构造；岩浆补给、通量和储存；以及热液系统和生物群落的稳定性，国家科学院最近的一份报告将喷发规模和频率的量化作为重要的重要组成部分。然而，由于辐射测量技术的不足，以及与海底观测和收集样本相关的巨大技术挑战，在地质记录中区分和准确地确定单个海底流的年代仍然具有挑战性。尽管在 EPR 和胡安德富卡海岭的轴海山记录了北纬 9° 的喷发历史方面投入了大量精力，但在空间和时间上都受到了限制。可变的全球系统需要更多的数据，并且可能需要新的方法，通过将 AUV（自主水下航行器）测绘与 HOV 相结合来量化东南太平洋海隆的喷发时间。 （载人车辆）观测和样本收集将指导采样位置并提供重要的解释背景，以及计算流量的可能性将与地磁古强度提供的时间约束相结合。定义喷发簇。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，并为流量分布的 3D 统计模型提供重要约束。结合现有地震反射数据对 2A 层厚度的估计，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，并可针对其他洋中脊设置进行测试和应用。此外，拟议的工作将提供与经过深入研究的 9°N 段的对比点，并扩展少数经过深入研究的山脊段。该奖项反映了 NSF 的法定使命，并被认为是值得的通过使用基金会的智力优势和更广泛的影响审查标准进行评估来获得支持。