Grain size and XRD analysis on Site 162-983 ...

• Main Authors: Jonkers, Lukas, Barker, Stephen, Hall, Ian R, Prins, Maarten Arnoud
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2015
• Subjects: Ocean Drilling Program ODP; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.854773; https://doi.pangaea.de/10.1594/PANGAEA.854773

The grain size of deep-sea sediments provides an apparently simple proxy for current speed. However, grain size-based proxies may be ambiguous when the size distribution reflects a combination of processes, with current sorting only one of them. In particular, such sediment mixing hinders reconstruction of deep circulation changes associated with ice-rafting events in the glacial North Atlantic because variable ice-rafted detritus (IRD) input may falsely suggest current speed changes. Inverse modeling has been suggested as a way to overcome this problem. However, this approach requires high-precision size measurements that register small changes in the size distribution. Here we show that such data can be obtained using electrosensing and laser diffraction techniques, despite issues previously raised on the low precision of electrosensing methods and potential grain shape effects on laser diffraction. Down-core size patterns obtained from a sediment core from the North Atlantic are similar for both ... : Supplement to: Jonkers, Lukas; Barker, Stephen; Hall, Ian R; Prins, Maarten Arnoud (2015): Correcting for the influence of ice-rafted detritus on grain size-based paleocurrent speed estimates. Paleoceanography, 30(10), 1347-1357 ...