Rare earth elements and yttrium (REY) in glacial meltwaters and their potential impact on the REY distribution in Modern and Precambrian seawater

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Global warming is accelerating the retreat of polar ice caps and alpine glaciers and enhances the input of glacial meltwater into the oceans. This situation is not unique in Earth history, as rapid deglaciation also characterized the end of major low-latitude glaciations (“Snowball Earth episodes”) in the Neoproterozoic and Paleoproterozoic. It has even been suggested that such input temporarily dominated the rare earths and yttrium (REY) inventory of Neoproterozoic seawater. However, little is known about the impact of glacial meltwaters on the seawater distribution of particle-reactive elements with short marine residence times, such as the REY. This is mainly due to (i) a quasi non-existing data base with regard to the REY distribution in glacial meltwaters and (ii) a lack of knowledge about the behaviour of those REY that are truly dissolved and those that are bound to inorganic (nano)particles (present as a component of rock flour and volcanic ash) during estuarine mixing with seawater. Thus, the distribution and behavior of trace elements, in particular of REY, will be studied in glacial meltwaters from Iceland and Greenland, that are typically poor in organic but very rich in inorganic (nano)particles (volcanic ash and rock flour). Meltwater impact on the distribution of REY in seawater will be determined by mixing experiments between glacial meltwaters and seawater in the laboratory. The results will then be used to better characterize the REY signature of continental run-off into the modern and the Precambrian oceans.