Collaborative Research: Linking High 3He/4He to Other Isotopic Systems in Baffin Island Lavas

稀有的火山岩同位素轻氦（即，高的3 He/4 He比率）被认为含有从地球地幔底部早期形成和长期隔离的储层中以羽状上升的物质。加拿大北极巴芬岛火山喷发的熔岩具有最高的3 He/4 He比值，是研究地球深部成层和长期演化的最佳场所。该项目将采用新的地球化学技术研究2018年在巴芬岛收集的一套高3 He/4 He熔岩。该项目的主要目标是提高我们对氦在岩浆环境中行为的理解。结合对样品的岩石学和地球化学评估，我们的研究结果将为地球深部过程提供新的见解。这个合作项目将支持伍兹霍尔海洋研究所和加州理工学院的研究生和高度专业化的技术支持人员。该项目团队还将与马萨诸塞州的康复中心合作，为当地居民提供就业机会。所有结果将发表在同行评审的期刊上，并翻译成因纽特语，与协助实地考察的巴芬岛因纽特人社区分享。了解地球深部的组成和长期演变依赖于将高3 He/4 He比率与火山岩中的其他化学成分联系起来的能力。本研究将通过结合详细的岩相学和地球化学观察以及精确的3 He/4 He测量来研究氦与其他元素的耦合（脱耦合）。该项目将利用创新技术，包括氦扩散实验，X射线计算机断层扫描，激光烧蚀微钻孔和单颗粒破碎，以研究氦在橄榄石晶体中的流动性，橄榄石晶体是熔岩中氦的主要宿主。为了填补巴芬岛熔岩地球化学方面的知识空白，研究人员还将测量186 Os、182 W和较重的惰性气体（Ne、Ar和H2O）同位素丰度。对这些未充分研究的熔岩进行全面的地球化学评估，将为神秘的地球深部过程提供新的视角。这个合作项目将支持伍兹霍尔海洋研究所和加州理工学院的研究生和高度专业化的技术支持人员。项目成员将与马萨诸塞州的康复中心合作，为当地居民提供就业机会。所有研究结果将发表在同行评审的期刊上，并翻译成因纽特语，与协助实地工作的巴芬岛因纽特人社区分享。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Rare volcanic rocks with isotopically light helium (i.e., high 3He/4He ratios) are thought to contain material that ascended in plumes from early formed and long isolated reservoirs at the base of Earth's mantle. Lavas erupted on Baffin Island in arctic Canada have the highest 3He/4He ratios found in any terrestrial rocks and thus afford the best opportunity to investigate the stratification and long-term evolution of the deep Earth. This project will employ novel geochemical techniques to study a suite of high 3He/4He lavas collected on Baffin Island in 2018. The primary objective of the project is to improve our understanding of helium behavior in magmatic settings. Combined with a thorough petrologic and geochemical assessment of the samples, our results will provide new insights about deep Earth processes. This collaborative project will support graduate students and highly specialized technical support staff at Woods Hole Oceanographic Institution and California Institute of Technology. The project team also will partner with a Massachusetts-based rehabilitation center to provide employment opportunities to local residents. All results will be published in peer-reviewed journals, as well as translated into Inuktitut and shared with the Baffin Island Inuit communities that assisted with fieldwork.Understanding the composition and the long-term evolution of the deep Earth relies on an ability to link high 3He/4He ratios to other chemical components in volcanic rocks. This study will investigate helium (de)coupling from other elements by combing detailed petrographic and geochemical observations with precise 3He/4He measurements. The project will utilize innovative techniques including helium diffusion experiments, X-ray computed tomography, laser ablation micro-drilling, and single-grain crushing to investigate helium mobility in olivine crystals, which are the primary hosts of helium in the lavas. To fill knowledge gaps about Baffin Island lava geochemistry, researchers also will measure 186Os, 182W, and heavier noble gas (Ne, Ar, and Xe) isotopic abundances. This comprehensive geochemical assessment of these understudied lavas will offer a fresh perspective on enigmatic deep Earth processes. This collaborative project will support graduate students and highly specialized technical support staff at Woods Hole Oceanographic Institution and California Institute of Technology. Project members will partner with a Massachusetts-based rehabilitation center to provide employment opportunities to local residents. All results will be published in peer-reviewed journals, as well as translated into Inuktitut and shared with the Baffin Island Inuit communities that assisted with fieldwork.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.