Collaborative Research: Interpreting the record of Antarctic sediment influenced by metal-rich hydrothermal deposits from their accumulation through early diagenesis and burial

合作研究：解释受富含金属热液矿床影响的南极沉积物的记录，这些沉积物通过早期成岩作用和埋藏而积累

• 批准号: 1847509
• 负责人: Natascha Riedinger
• 金额: $ 6.49万
• 依托单位: Oklahoma State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-15 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1847509&HistoricalAwards=false
• 关键词: Collaborative; Research; Interpreting; record; Antarctic

The Antarctic region is surrounded by spreading centers, areas on the seafloor where volcanic eruptions and vigorous hydrothermal venting typify the environment. Hydrothermal venting releases metals into the water column. These metals are of some economic interest as a natural resource, and they can impact the biosphere, including affecting faunal composition and microbial processes that dominate in the region. Additionally, hydrothermal metals settle onto the seafloor along with other sediments. Marine sediments provide a window into the past as they accumulate, with each layer containing information about oceanographic condition at the time of their deposition. However, the amount and composition of trace metals in the sediment can change as hydrothermal fluids circulate through the sediment and oceanic crust, thereby impacting this geologic record. The goal of this project is to collect samples during a sea-going expedition on the research vessel R/V Polarstern and identify the impact of hydrothermal fluids on the sedimentary environment. The results will advance our knowledge on how hydrothermal vents impact the geochemical signals in sediment deposit and with that their application to reconstruct paleoenvironmental conditions. The project supports the training of a graduate student.During the last few years several expeditions in the Southern Ocean have focused on reconstructing paleoceanographic conditions in this climate-sensitive region of the planet. In this previous work, variations in redox-sensitive element distributions in the sediment were proposed as a valuable tool for unravelling changes in productivity and redox conditions in the water column over time. However, the potential effect of metal-rich sediment on this paleoceanographic record has remained unstudied. The goal of this project is to decipher the potential impact of hydrothermal systems in the Antarctic region onto the sedimentary trace metal signatures frequently applied for paleo redox reconstructions. For this purpose we will join an international expedition on the R/V Polarstern (P119). Hydrothermal deposits and sediments will be recovered using ROV-guided push cores and piston cores. The sedimentary signal will be compared with the trace metal signal in the hydrothermal fluids from two vent sites and background pelagic opal-rich sediment typical for this area. For this purpose, sulfur, iron and manganese phases and selected trace metals will be analyzed in the solid phase and pore waters. Samples will be analyzed for selected constituents onboard the ship. All other analyses will be carried out at home institutes and samples will be prepared and stored accordingly. The data will enhance our understanding of the alteration of primary proxy-signals and the potential impact of hydrothermal fluids on these proxies and could thus be crucial for its application as redox proxy for sites in vicinity to hydrothermal input. Additionally, the results will complement parallel planned research at this location aimed at understanding the role of hydrothermal vents on faunal composition and microbial processes in these extreme environments.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.

南极地区周围环绕着扩张中心，海底的火山爆发和强烈的热液喷口是环境的典型特征。热液喷口将金属释放到水柱中。这些金属作为一种自然资源具有一定的经济利益，它们可以影响生物圈，包括影响该地区占主导地位的动物组成和微生物过程。此外，热液金属与其他沉积物一起沉淀到海底。海洋沉积物的积累为了解过去提供了一个窗口，每一层都包含了沉积时海洋状况的信息。然而，随着热液流体在沉积物和海洋地壳中循环，沉积物中微量金属的数量和组成会发生变化，从而影响这一地质记录。该项目的目标是在R/V北极星号科考船的一次海上考察中收集样本，并确定热液流体对沉积环境的影响。研究结果将有助于我们进一步了解热液喷口对沉积物地球化学信号的影响，并利用这些信号重建古环境条件。该项目支持培养一名研究生。在过去的几年里，在南大洋进行的几次考察集中在重建地球上这个气候敏感地区的古海洋学条件。在之前的工作中，沉积物中氧化还原敏感元素分布的变化被认为是揭示水柱中生产力和氧化还原条件随时间变化的有价值的工具。然而，富金属沉积物对这一古海洋学记录的潜在影响尚未得到研究。该项目的目标是破译南极地区热液系统对沉积微量金属特征的潜在影响，这些特征经常用于古氧化还原重建。为此目的，我们将参加北极星号（R/V Polarstern）的一次国际考察。热液矿床和沉积物将采用rov导向的推式岩心和活塞式岩心进行回收。将沉积信号与两个热泉点的热液流体中的微量金属信号以及本地区典型的远洋富蛋白石背景沉积物进行比较。为此，将分析固相和孔隙水中的硫、铁和锰相以及选定的微量金属。样品将在船上分析选定的成分。所有其他分析将在国内研究所进行，样品将相应地准备和储存。这些数据将增强我们对主要代理信号的变化以及热液流体对这些代理信号的潜在影响的理解，因此对于将其作为热液输入附近地点的氧化还原代理至关重要。此外，这些结果将补充平行计划的研究，旨在了解热液喷口在这些极端环境中对动物组成和微生物过程的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。