Universität zu Köln

Morlock, Marina A. ORCID: 0000-0001-6495-8267, Vogel, Hendrik ORCID: 0000-0002-9902-8120, Nigg, Valentin ORCID: 0000-0001-5512-4930, Ordonez, Luis, Hasberg, Ascelina K. M., Melles, Martin, Russell, James M. and Bijaksana, Satria (2019). Climatic and tectonic controls on source-to-sink processes in the tropical, ultramafic catchment of Lake Towuti, Indonesia. J. Paleolimn., 61 (3). S. 279 - 296. DORDRECHT: SPRINGER. ISSN 1573-0417

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Abstract

Humid tropical landscapes are subject to intense weathering and erosion, which strongly influence sediment mobilisation and deposition. In this setting, we aimed to understand how geomorphology and hydroclimate altered the style and intensity of erosion and sediment composition in a tropical lake and its tectonically active catchment. Lake Towuti (2.75 degrees S, 121.5 degrees E) is one of the oldest and deepest lakes in Indonesia, with uninterrupted lacustrine sedimentation over several glacial-interglacial cycles. Here we present results from a novel set of Lake Towuti surface sediment, bedrock and soil samples from the catchment, and two existing sediment cores that extend to 30,000 and 60,000years before present. We studied the catchment morphology, soil properties, geochemistry, and clay and bulk mineralogy. Results from several river long profiles show clear signs of tectonic activity, which enhances river incision, favours mass movement processes, and together with remobilisation of fluvial deposits, strongly influences modern sedimentation in the lake. Material from the Mahalona River, the lake's largest inflow, dominates modern sediment composition in Towuti's northern basin. The river transports Al-poor and Mg-rich sediments (mainly serpentines) to the lake, indicating river incision into the Mg-rich serpentinised peridotite bedrock. Relatively small, but important additional contributions of material, come from direct laterite-derived input and the Loeha River, which both provide Al-rich and Mg-poor sediment to the lake. Over time, the Al/Mg and kaolinite-to-serpentine ratios varied strongly, primarily in response to lake-level fluctuations driven by hydroclimatic changes. In the past 60,000years, both the Al/Mg and kaolinite-to-serpentine ratios showed variations sensitive to changes in climate boundary conditions across glacial-interglacial cycles, while tectonic activity had less influence on changes in sediment composition on these short time-scales.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Morlock, Marina A. UNSPECIFIED orcid.org/0000-0001-6495-8267 UNSPECIFIED Vogel, Hendrik UNSPECIFIED orcid.org/0000-0002-9902-8120 UNSPECIFIED Nigg, Valentin UNSPECIFIED orcid.org/0000-0001-5512-4930 UNSPECIFIED Ordonez, Luis UNSPECIFIED UNSPECIFIED UNSPECIFIED Hasberg, Ascelina K. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Melles, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Russell, James M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bijaksana, Satria UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-155336
DOI:	10.1007/s10933-018-0059-3
Journal or Publication Title:	J. Paleolimn.
Volume:	61
Number:	3
Page Range:	S. 279 - 296
Date:	2019
Publisher:	SPRINGER
Place of Publication:	DORDRECHT
ISSN:	1573-0417
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CENTRAL SULAWESI; LAST; VEGETATION; RECONSTRUCTION; PERSPECTIVES; SOROAKO Multiple languages Environmental Sciences; Geosciences, Multidisciplinary; Limnology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15533