Universität zu Köln

Sheppard, Rachel Y., Milliken, Ralph E., Russell, James M., Dyar, M. Darby, Sklute, Elizabeth C., Vogel, Hendrik ORCID: 0000-0002-9902-8120, Melles, Martin, Bijaksana, Satria ORCID: 0000-0001-6374-4128, Morlock, Marina A. and Hasberg, Ascelina K. M. (2019). Characterization of Iron in Lake Towuti sediment. Chem. Geol., 512. S. 11 - 31. AMSTERDAM: ELSEVIER SCIENCE BV. ISSN 1872-6836

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Abstract

Sediments collected from Lake Towuti, an ultramafic-hosted lake in Indonesia, preserve a visible alternating pattern of red and green sediments due to variations in clay mineral and Fe-oxide composition and abundance consistent with changes in iron oxidation state through time. Spectral, mineralogical, and chemical analyses on soils, river, and sediment samples from across the lake and its catchment were carried out to better understand the starting composition of these sediments and the processes that affected them before and after deposition. Despite high Fe abundances in all samples and abundant Fe oxides in lateritic source regions, mineralogical analyses (X-ray diffraction (XRD) and Mossbauer spectroscopy) of the modern lake sediment show almost no well-crystalline iron oxides. In addition, sequential Fe extractions suggest an increasing proportion of easily extractable, poorly crystalline (X-ray amorphous) material with burial depth. XRD, bulk chemistry, and visible-near infrared (VNIR) spectral reflectance measurements demonstrate that clay mineralogy and bulk chemistry can be inferred from VNIR data. These results provide evidence for variations in Fe mineralogy and crystallinity based on location in this source to sink system. Understanding how the mineralogy and chemistry of sediments within a ferruginous lake basin are affected by transport, chemical alteration, physical alteration, and deposition from source to sink on Earth, and the degree to which these trends and underlying processes can be inferred from chemical and spectral properties, may provide useful direction in assessing paleoenvironmental conditions in other terrestrial lakes as well as ancient lacustrine environments preserved in the stratigraphic record of Mars.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Sheppard, Rachel Y. UNSPECIFIED UNSPECIFIED UNSPECIFIED Milliken, Ralph E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Russell, James M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dyar, M. Darby UNSPECIFIED UNSPECIFIED UNSPECIFIED Sklute, Elizabeth C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Vogel, Hendrik UNSPECIFIED orcid.org/0000-0002-9902-8120 UNSPECIFIED Melles, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Bijaksana, Satria UNSPECIFIED orcid.org/0000-0001-6374-4128 UNSPECIFIED Morlock, Marina A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hasberg, Ascelina K. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-148534
DOI:	10.1016/j.chemgeo.2019.02.029
Journal or Publication Title:	Chem. Geol.
Volume:	512
Page Range:	S. 11 - 31
Date:	2019
Publisher:	ELSEVIER SCIENCE BV
Place of Publication:	AMSTERDAM
ISSN:	1872-6836
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language REFLECTANCE SPECTROSCOPY; GALE CRATER; INDONESIA; RECONSTRUCTION; MINERALOGY; EVOLUTION; MUDSTONE; DEPOSITS Multiple languages Geochemistry & Geophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/14853