Provenance, transport and diagenesis of sediment in polar areas: a case study in Profound Lake, King George Island, Antarctica

• Published in: Polar Research
• Main Authors: Hernández, A.C., Bastias, J., Matus, D., Mahaney, W.C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor and Francis 2018
• Subjects: EDS: energy dispersive spectrometry; Environmental interpretation; Hydrothermal alteration; Lake sediment; Micro-texture characteristics; Quartz grain micromorphology; SEM: scanning electron microscopy; XRD: x-ray diffraction; Antarctic; King George Island; Uruguay; Inach; Collins Glacier; Profound Lake; Antarc*; Antarctica; Polar Research
• Online Access: http://repositorio.unab.cl/xmlui/handle/ria/11012; https://doi.org/10.1080/17518369.2018.1490619

Indexación: Scopus. This study was supported by the Venezuelan Antarctic Program of the Ministerio del Poder Popular para la Ciencia, Tecnología e Innovación. JB acknowledges the Instituto Antártico Chileno project INACH RT0614, which supported his participation. Detailed scanning electron microscopy (SEM) micro-texture and mineralogical analysis of lacustrine sediment recovered from Profound Lake (also known as Uruguay Lake), Antarctica, was conducted in the foreland area of the Collins Glacier, King George Island. Very coarse and coarse sand grade size fractions (2 mm–600 μm) were examined with SEM/energy dispersive spectrometry, while the total sand fraction and fines (silt + clay) were examined using x-ray diffraction to determine relationships to source rock, weathering and transport history and long-term clay mineral weathering, all of which are poorly understood in polar areas. The mineralogy of these sediments was compared with petrographical information of the country rock to identify potential detrital sources. The association of recovered detrital minerals, sometimes strongly pre-weathered, supports release from source rock of basaltic and andesitic compositions. The micro-texture analysis of quartz, magnetite and various plagioclase grains show micro-features that reveal a complex weathering–diagenesis history tentatively extending into the Paleogene. The bedrock was eroded mostly by glacial processes and mechanical action presumed to result from glacial crushing. Alteration minerals, likely the product of pre-weathering, are probably sourced from weathered bedrock during contact with the sub-aerial atmosphere prior to entrainment. However, amorphous silica precipitation indicates weathering subsequent to glacial erosion from the source bedrock. Cracks of variable dimensions are mostly characteristic of either frost weathering or glacial transport, and involve mechanical and chemical processes. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. ...