Ge/Si and Ge Isotope Fractionation During Glacial and Non-glacial Weathering: Field and Experimental Data From West Greenland ...

• Main Authors: Baronas, JJ, Hammond, DE, Bennett, MM, Rouxel, O, Pitcher, LH, Smith, LC
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media SA 2021
• Subjects: glacial weathering; germanium; isotope fractionation; Amorphous silica; experimental dissolution; Greenland; glacier
• Online Access: https://dx.doi.org/10.17863/cam.66421; https://www.repository.cam.ac.uk/handle/1810/319300

Glacial environments offer the opportunity to study the incipient stages of chemical weathering due to the high availability of finely ground sediments, low water temperatures, and typically short rock-water interaction times. In this study we focused on the geochemical behavior of germanium (Ge) in west Greenland, both during subglacial weathering by investigating glacier-fed streams, as well as during a batch reactor experiment by allowing water-sediment interaction for up to 2 years in the laboratory. Sampled in late August 2014, glacial stream Ge and Si concentrations were low, ranging between 12–55 pmol/L and 7–33 µmol/L, respectively (Ge/Si = 0.9–2.2 µmol/mol, similar to parent rock). As reported previously, the dissolved stable Ge isotope ratio (δ 74 Ge) of the Watson River was 0.86 ± 0.24‰, the lowest among global rivers and streams measured to date. This value was only slightly heavier than the suspended load (0.48 ± 0.23‰), which is likely representative of the bulk parent rock composition. Despite ...