Quantifying Sampling Biases and Silicate-Derived Sr in Continental Runoff: A Coupled 87Sr/86Sr - 88Sr/86Sr Study

海水的锶同位素(~(87)Sr/~(86)Sr)记录是重建最好的海洋同位素记录之一。它被广泛用于估计大陆和热液对海水的输入的时间变化，并且时间变化与冰川、造山和重大岩浆事件的时期相关。尽管有这一令人印象深刻的记录，但对目前海水中锶的质量平衡的估计基本上不一致，这突显了解释海洋锶同位素记录的挑战。该项目旨在调查目前对大陆径流进入海洋的估计有多严重的偏差，以及如何纠正这种偏差。对海洋记录的解释关键取决于对当今物质平衡和强迫因素的不偏不倚的理解。除了放射性成因(87Sr/86Sr)同位素组成外，稳定的(88Sr/86Sr)同位素特征还可以深入了解硅酸盐和碳酸盐衍生锶之间的平衡，从而了解硅酸盐和碳酸盐风化之间的平衡。这项研究将在全球河流天文台的保护伞下进行，这是一个由科学家和社区志愿者组成的合作国际网络，旨在以时间序列的方式观察河流系统。公民科学家和REU的学生将对北美西海岸和东海岸的代表性河流进行采样。邀请本地学校参与“我的河流，我的家”学生艺术计划。

The Strontium isotope (87Sr/86Sr) record of seawater is one of the best-reconstructed marine isotope records. It has been widely used to estimate temporal changes of continental and hydrothermal inputs to seawater, and temporal variations have been correlated with periods of glaciations, mountain building and major magmatic events. Despite this impressive record, estimates of the present-day mass balance of strontium in seawater fundamentally disagree, highlighting the challenges of interpreting the marine strontium isotope record.This project aims at investigating how severely present estimates of continental runoff into the ocean are biased, and how such biases can be corrected. The interpretation of the marine record critically hinges on an unbiased understanding of the present-day mass balance and forcing factors. In addition to the radiogenic (87Sr/86Sr) isotope composition, the stable (88Sr/86Sr) isotope signature may yield insights into the balance of silicate- vs carbonate-derived strontium, and thus the balance between silicate and carbonate weathering.The study will be conducted under the umbrella of the Global Rivers Observatory, a collaborative, international network of scientists and community volunteers aimed at observing river systems in time-series fashion. Citizen scientists and REU students will be engaged in sampling representative rivers draining the West and East coasts of North America. Local schools are invited to participate in the "My River, My Home" student art project.