Collaborative Research: Rise and Fall of Galapagos Seamounts

合作研究：加拉帕戈斯海山的兴衰

• 批准号: 1634685
• 负责人: Samuel Soule
• 金额: $ 8.76万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634685&HistoricalAwards=false
• 关键词: Collaborative; Research; Rise; Fall; Galapagos

The Galapagos Islands are unique in their construction. The islands sit on a laterally extensive platform consisting of thick layered lava flows and intrusions that rises 3 kilometers above the surrounding seafloor. Sitting on this platform and peeking out of the water are major volcanic islands that form the basis of Darwin's treatise on the Origin of Species. Interestingly enough, the islands only comprise about 5 % of the volume of the Galapagos platform, which is thought to have originated by melting of the mantle and oceanic lithosphere via a thermal plume originating deep in the mantle. With the exception subaerially exposed parts of the volcanic islands, much of the Galapagos platform remains unsampled and unstudied. A recent oceanographic expedition to the Galapagos, funded by the Dalio Foundation and the Ocean Exploration Trust, mapped part of the platform between some of the major islands and discovered 70 previously unknown submerged volcanic edifices that appear to sport wave-cut erosional features on their surface, indicating that, once, parts of them were exposed above sea level. Over 150 rock samples were collected on the expedition, with hopes that their geochemistry would help to unravel the relationships between the plume source of magma and the chemistry of the volcanoes themselves. This research project will analyze these samples and provide more sophisticated processing of the bathymetric and other geophysical data that was collected on the recent cruise to the Galapagos in hopes of better understanding the recent volcanic history and the rise and fall of the platform with relation to sea level. Using cosmogenic isotopes and the He that is released during radioactive decay, it is hoped that the vertical movement of the small submerged volcanic features displaying subaerial erosional features can be dated and related to sea level, thermal upwelling due to plume resurgence, and platform subsidence over time. Hypotheses to be tested include examining whether the 70 small Galapagos seamounts each represent their own tapping into the mantle upwelling with magmatic systems that are distinct from the adjacent volcanic islands and each other. This will be tested by analyzing samples from the seamounts for major and trace elements, radiogenic isotopes of Sr, Nd, U, and Pb, and noble gases. These data will be used to look for geochemical similarities and differences. Coupled with this magma source study will be a refinement of the collected seafloor topography to examine relationships between seamounts and their geomorphic features and to identify additional signs of emergence from the ocean, which may reveal information about sea level changes over time. Broader impacts of the work include providing critical site characterization for the Galapagos Marine Research, a UNESCO World Heritage Site. Because the submerged volcanic edifices are hotspots of marine life and biodiversity, this work also provides important input into the development of Galapagos protected biological site characterization. Additional impacts include support of an early career faculty member whose gender is under-represented in the sciences and who is employed at an institution in Idaho, an EPSCoR state (i.e., a state that does not receive significant federal funding); significant student training; and outreach to transmit the excitement and wonder of marine geology research to the public. Results of the geophysical and submarine topographic studies will be used by the Ecuadorian government to assess potential tsunami hazards from Galapagos volcanic structures.

加拉帕戈斯群岛的建筑独一无二。 这些岛屿坐落在一个横向广阔的平台上，该平台由厚厚的层状熔岩流和侵入物组成，高出周围海底 3 公里。坐落在这个平台上并从水面向外望去的是主要的火山岛，这些火山岛构成了达尔文《物种起源》论文的基础。 有趣的是，这些岛屿仅占加拉帕戈斯平台体积的 5% 左右，加拉帕戈斯平台被认为是由地幔和海洋岩石圈通过源自地幔深处的热羽流融化而形成的。 除了火山岛暴露在空中的部分外，加拉帕戈斯平台的大部分地区仍未采样和研究。 最近由达利奥基金会和海洋探索信托基金会资助的加拉帕戈斯海洋学考察绘制了一些主要岛屿之间平台的部分地图，并发现了 70 个以前未知的水下火山建筑物，这些火山建筑物的表面似乎具有波浪切割侵蚀特征，表明它们的一部分曾经暴露在海平面以上。 此次探险收集了 150 多个岩石样本，希望它们的地球化学成分能够帮助揭示岩浆羽流来源与火山本身化学成分之间的关​​系。 该研究项目将分析这些样本，并对最近加拉帕戈斯群岛航行中收集的测深和其他地球物理数据进行更复杂的处理，希望更好地了解最近的火山历史以及平台与海洋的升降等级。 利用宇宙成因同位素和放射性衰变过程中释放的氦气，希望能够确定显示出地面侵蚀特征的小型水下火山特征的垂直运动的年代，并将其与海平面、羽流复苏引起的热上升以及平台沉降联系起来。时间。 待检验的假设包括检验 70 个加拉帕戈斯小海山是否各自代表着各自对地幔上升流的岩浆系统的利用，这些岩浆系统与邻近的火山岛和彼此不同。这将通过分析海山样品中的主量元素和微量元素、锶、钕、铀和铅的放射性同位素以及稀有气体来进行测试。这些数据将用于寻找地球化学的相似点和差异。 与这项岩浆源研究相结合，将对收集到的海底地形进行细化，以检查海山及其地貌特征之间的关系，并确定从海洋中出现的其他迹象，这可能会揭示有关海平面随时间变化的信息。这项工作的更广泛影响包括为联合国教科文组织世界遗产加拉帕戈斯海洋研究提供关键地点特征描述。 由于水下火山建筑物是海洋生物和生物多样性的热点，这项工作也为加拉帕戈斯受保护的生物地点特征的发展提供了重要的投入。其他影响包括对早期职业教员的支持，该教员的性别在科学领域代表性不足，并且受雇于 EPSCoR 州爱达荷州的一个机构（即没有获得大量联邦资助的州）；重要的学生培训；向公众传播海洋地质研究的兴奋和奇迹。 厄瓜多尔政府将利用地球物理和海底地形研究的结果来评估加拉帕戈斯火山结构潜在的海啸危险。

项目成果

Petrogenesis of alkalic seamounts on the Galápagos Platform

加拉帕戈斯平台碱性海山的岩石成因

• DOI: 10.1016/j.dsr2.2017.09.019
• 发表时间: 2018-04
• 期刊: Deep Sea Research Part II: Topical Studies in Oceanography
• 作者: Schwartz, Darin M.;Wanless, V. Dorsey;Berg, Rebecca;Jones, Meghan;Fornari, Daniel J.;Soule, S. Adam;Lytle, Marion L.;Carey, Steve
• 通讯作者: Carey, Steve

Identification of Erosional Terraces on Seamounts: Implications for Interisland Connectivity and Subsidence in the Galápagos Archipelago

海山侵蚀台地的识别：对加拉帕戈斯群岛岛间连通性和沉降的影响

• DOI: 10.3389/feart.2018.00088
• 发表时间: 2018-07
• 期刊: Frontiers in Earth Science
• 影响因子: 2.9
• 作者: Schwartz, Darin M.;Soule, S. Adam;Wanless, V. Dorsey;Jones, Meghan R.
• 通讯作者: Jones, Meghan R.

Monogenetic Near‐Island Seamounts in the Galápagos Archipelago

加拉帕戈斯群岛的单生近岛海山

• DOI: 10.1029/2020gc008914
• 发表时间: 2020-12
• 期刊: Geosystems
• 作者: Schwartz, D. M.;Wanless, V. D.;Soule, S. A.;Schmitz, M. D.;Kurz, M. D.
• 通讯作者: Kurz, M. D.

Submarine Deep-Water Lava Flows at the Base of the Western Galápagos Platform

西加拉帕戈斯地台底部的海底深水熔岩流

• DOI: 10.1029/2018gc007632
• 发表时间: 2018-10
• 期刊: Geosystems
• 作者: Anderson, Molly;Wanless, V. Dorsey;Schwartz, Darin M.;McCully, Emma;Fornari, Daniel J.;Jones, Meghan R.;Soule, S. Adam
• 通讯作者: Soule, S. Adam