The Geochemistry of River Particulate Matter from High-Standing Oceanic Islands (EPSCoR)

9725543里昂米利曼和西维茨基(1992年)最近的沉积物通量研究表明，排出澳大利亚和亚洲之间的高位海洋岛屿的河流可能占海洋总沉积物通量的50%。这些物质很可能被直接转移到深海，部分原因是与这些岛屿周围活跃的边缘相关的狭窄的沿海陆架区域。如果这是真的，那么陆地对海洋的地球化学输入，以及基于较大河流系统沉积物测量的平衡可能是错误的。我们收集并分析了新西兰四个水系的河流沉积物。我们的资料表明，相对于海相粘土，这些河流沉积物亏损Ba、Co、Cu、Hg、Mo、Ni、Zn和Pb，而富锶。壳层标准化稀土元素配分模式显示中等稀土元素富集，Eu正异常。我们的初步结果表明，这些新西兰沉积物与海相碎屑沉积物具有不同的地球化学特征。在对这项研究的三年支持期间，私人投资促进机构计划从新西兰的溪流和河流中收集200至300个河流颗粒物(RPM)样本。将使用最先进的技术对这些样品进行分析，以确定从这些高海拔岛屿到海洋的RPM地球化学通量是否不同于Martin和Meybeck(1979)确定的主要河流通量。如果是，将进行新的通量计算，以便更好地量化RPM对海洋地球化学的重要性。此外，还将从地质和气候相似但面积和产沙量不同的流域收集样本，以评估储存对RPM地球化学的重要性。在第二年，将对不同地质但气候相似的流域的样本进行比较，以建立基岩类型与RPM化学之间的联系。所有这些工作都将与新西兰克赖斯特彻奇国家水与大气研究所的同事密切合作完成。

9725543 Lyons Recent sediment flux work by Milliman and Syvitski (1992) suggest that rivers draining high-standing oceanic islands between Australia and Asia may contribute 50% of the total sediment flux to the oceans. This material is likely to be transferred directly into the deep ocean due, in part, to the narrow coastal-shelf areas associated with the active margins surrounding these islands. If this is true, terrestrial geochemical inputs to the ocean, and, hence, balances based on sediment measurements from larger river systems may be in error. We have collected and analyzed riverine sediments from four river systems in New Zealand. Our data indicate that these river sediments are depleted in Ba, Co, Cu, Hg, Mo, Ni, Zn and Pb and enriched in Sr, relative to marine clays. Shele-normalized REE patterns show intermediate REE enrichments with positive Eu anomalies. Our preliminary results indicate that these New Zealand sediments have different geochemical signatures than marine clastic sediments. During the three years of support for the research, the PIs plan to collect 200 to 300 riverine particulate matter (RPM) samples from streams and rivers in New Zealand. These samples will be analyzed, using state-of-the-art techniques in order to establish if the RPM geochemical flux to the oceans from these high-standing islands are different than from the major riverine flux established by Martin and Meybeck (1979). If they are, new flux calculations will be undertaken in order to better quantify the importance of RPM on marine geochemistry. In addition, samples will be collected from watersheds of similar geology and climate but of different area and sediment yield in order to evaluate the importance of storage on the RPM geochemistry. In Year 2, samples from watersheds of differing geology but similar climate will be compared in order to establish the linkage between bedrock types and RPM chemistry. All this work will be done in close cooperation with colleagues at the National Institute for Water and Atmospheric Research Ltd. in Christchurch, New Zealand.