Sedimentology and geochemistry of sediments from the Sunda Shelf
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
2000
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| _version_ | 1867172223984336896 |
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| author | Hanebuth, Till J J |
| author_facet | Hanebuth, Till J J |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The Sunda Shelf represents one of the largest tropical shelf areas in the world. Its broad extension, the very low gradient, and the tectonical stability offer excellent conditions for a reconstruction of the exposure and flooding history during the last glacial cycle. A high fluvial input dominated this siliciclastic deposystem over long time intervals. The proximal part of the transect of the research cruise Sonne-115 covers the riverine structures of the ancient North Sunda River ('Molengraaff' River) from -70 to -126 m modern water depth. The aim of the study presented here was to analyse the stratigraphic architecture of the Sunda Shelf during the last 50 kyr, to develop a high-resolution sea-level curve, as well as to reconstruct the flooding history of this part of the world. The facies types examined in 36 sediment cores were classified by sedimentological and geochemical methods. 80 AMS-14C datings and additional fractionation measurement led to a high-resolution age determination. A shallow-seismic survey along and crosswise to the transect illustrated large- to medium-scale sediment structures. Eleven facies types were identified and related to the paleo-shoreline. They extend from terrestrial and coastline deposits to full-marine environments and were classified into five groups along the transect, which contain distinct local facies successions. The sea-level rise from 21 to 11 cal. kyr BP was determined by dating of plant remnants from the intertidal zone, following the retrograde migrating paleo-coastline. During lowstand, sea-level dropped at about -120 m. A conspicuous phase of the subsequent rise between 14.6 and 14.3 cal. kyr BP corresponding to meltwater pulse 1A was documented the first time and indicated as much as 16 m. In response to the sea-level changes during the last 50 kyr, characteristic processes formed the deposits and changed drastically several times until the terrigenous supply starved at about 11 kyr BP. Most remarkable were incised valley fills, which preserved deposits of the transgressive phase. A sequence-stratigraphic interpretation classified the deposits into three systems tracts and indicates, that three major factors controlled the depositional history: sediment input, physiography, and sea-level fluctuations. The specific modification of these factors in comparison to the general model was related to the asymmetry of the sea-level fall and rise and the extreme morphological conditions on the Sunda Shelf. Nevertheless, hiatuses of several thousand years and massive erosion activity were almost always predominantly affecting and strongly reducing the original sediment thickness. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_869934 |
| institution | PANGAEA |
| language | en |
| publishDate | 2000 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Sedimentology and geochemistry of sediments from the Sunda Shelf Hanebuth, Till J J GIK/IfG; Institute for Geosciences, Christian Albrechts University, Kiel The Sunda Shelf represents one of the largest tropical shelf areas in the world. Its broad extension, the very low gradient, and the tectonical stability offer excellent conditions for a reconstruction of the exposure and flooding history during the last glacial cycle. A high fluvial input dominated this siliciclastic deposystem over long time intervals. The proximal part of the transect of the research cruise Sonne-115 covers the riverine structures of the ancient North Sunda River ('Molengraaff' River) from -70 to -126 m modern water depth. The aim of the study presented here was to analyse the stratigraphic architecture of the Sunda Shelf during the last 50 kyr, to develop a high-resolution sea-level curve, as well as to reconstruct the flooding history of this part of the world. The facies types examined in 36 sediment cores were classified by sedimentological and geochemical methods. 80 AMS-14C datings and additional fractionation measurement led to a high-resolution age determination. A shallow-seismic survey along and crosswise to the transect illustrated large- to medium-scale sediment structures. Eleven facies types were identified and related to the paleo-shoreline. They extend from terrestrial and coastline deposits to full-marine environments and were classified into five groups along the transect, which contain distinct local facies successions. The sea-level rise from 21 to 11 cal. kyr BP was determined by dating of plant remnants from the intertidal zone, following the retrograde migrating paleo-coastline. During lowstand, sea-level dropped at about -120 m. A conspicuous phase of the subsequent rise between 14.6 and 14.3 cal. kyr BP corresponding to meltwater pulse 1A was documented the first time and indicated as much as 16 m. In response to the sea-level changes during the last 50 kyr, characteristic processes formed the deposits and changed drastically several times until the terrigenous supply starved at about 11 kyr BP. Most remarkable were incised valley fills, which preserved deposits of the transgressive phase. A sequence-stratigraphic interpretation classified the deposits into three systems tracts and indicates, that three major factors controlled the depositional history: sediment input, physiography, and sea-level fluctuations. The specific modification of these factors in comparison to the general model was related to the asymmetry of the sea-level fall and rise and the extreme morphological conditions on the Sunda Shelf. Nevertheless, hiatuses of several thousand years and massive erosion activity were almost always predominantly affecting and strongly reducing the original sediment thickness. |
| title | Sedimentology and geochemistry of sediments from the Sunda Shelf |
| topic | GIK/IfG; Institute for Geosciences, Christian Albrechts University, Kiel |
| url | https://doi.org/10.1594/PANGAEA.869934 |