Sedimentary analysis and magnetic properties of Lake Anónima, Vega Island

Antarctic science

Marcos A.E. Chaparro¹  Mauro A.E. Chaparro²  Francisco E. Córdoba³  Karina L. Lecomte⁴  José D. Gargiulo⁵  Ana M. Barrios⁶  Gimena M. Urán⁷  Nadia T. Manograsso Czalbowski⁸  Araceli Lavat⁹ 

[1] 1Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, CONICET-UNCPBA), Pinto 399, 7000 Tandil, Argentina;2Centro Marplatense de Investigaciones Matemáticas (CEMIM), Facultad de Ciencias Exactas y Naturales UNMDP, CONICET, Mar del Plata, Argentina;3Instituto de Ecorregiones Andinas (INECOA), Universidad Nacional de Jujuy-CONICET. Instituto de Geología y Minería, Av. Bolivia 1661 (4600), San Salvador de Jujuy, Argentina;4Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), CONICET Av. Vélez Sarsfield 1611, X5016GCA Córdoba, Argentina;5Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Av. Vélez Sarsfield 1611, X5016CGA Córdoba, Argentina;6Universidad de Granada, Av. del Hospicio, s/n, 18010 Granada, Spain;7Instituto Antártico Argentino (IAA), 25 De Mayo 1143, San Martín, Provincia de Buenos Aires, Argentina;8Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, CONICET-UNCPBA), Olavarría, Argentina;9Centro de Geociencias (UNAM), Blvd. Juriquilla 3001, 76230 Querétaro, México

关键词: Antarctica;    environmental magnetism;    grain size analysis;    hydrochemical studies;    lake sediments;    multivariate statistics;   

DOI  :  10.1017/S0954102017000116

学科分类：自然科学（综合）

来源: Cambridge University Press

【 摘 要 】

During the summer Lake Anónima experiences important changes in salinity and lake level fluctuations. Physicochemical data and field observations indicate that evaporative processes are dominant and that the water inflow is mainly provided by snow meltwater and streams. A multiproxy analysis of data from lake bottom sediments suggests that the main surface stream located south-west of the lake controls the clastic input and the spatial variation of sediment composition. Through an integrated analysis (magnetic, X-ray diffraction and Fourier transform infrared spectroscopy studies) magnetite and greigite minerals were identified in these lake sediments. Such ferrimagnetic minerals have ultra-fine grain sizes (<0.1 μm). Magnetic parameters and non-magnetic variables analysed by multivariate statistics reveal significant differences between silt facies (e.g. mass-specific susceptibility χ=109.6×10-8 m3 kg-1, remanent coercivity Hcr=49.2 mT and total organic carbon (TOC)=1.11%) and sand facies (e.g. χ=82.1×10-8 m3 kg-1, Hcr=44.7 mT and TOC=0.70%), and four recent depositional sub-environments were identified and characterized in Lake Anónima. This multiparameter analysis contributes to the understanding of present-day lacustrine dynamic and sedimentary processes. Lake Anónima may provide a useful analogue for the interpretation of other lacustrine basins in the Antarctic region.

【 授权许可】

CC BY