Composition and grain size distribution of laminated sediment core SO130_275KL from northeastern Arabian Sea off Pakistan
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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2018
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| _version_ | 1867167676351119360 |
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| author | Gaye, Birgit |
| author_facet | Gaye, Birgit |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Laminated sediments of the continental slope off the Makran coast in the northern Arabian Sea are well-known climate archives and record productivity as well as supply of material from land. Here we studied sediment core 275KL off Pakistan in concert with sediment trap, dust and river samples in order to characterise and quantify land-derived material deposited in varves and event layers. We analysed grain sizes, mineral assemblages, bulk components, and stable isotopes (δ13C, δ18O) of carbonates. In winter, enhanced river discharge is the main source of lithogenic matter contributing the major amounts to the total annual sedimentation of the northern Arabian Sea. During the late summer season, lithogenic matter accumulation is slightly enhanced, probably carried along with the southeastward blowing Levar winds from the Balochistan and the Sistan Basins and the summer monsoon discharge maximum of perennial streams. C/N ratios and stable carbon and oxygen isotopes could not be used to distinguish between organic matter produced on land and in the ocean, whereas stable carbon and oxygen isotope ratios of carbonates suggest that sedimentation of event layers is dominated by direct inputs from land. Catastrophic denudation and storm events occur on average once every 50 years and lead to sedimentation rates that exceed the mean annual sedimentations of 983 g m-2 yr-1 by 6 to 10 times. Nevertheless, due to their rare occurrence they contributed only 7% to the total sedimentation during the last ca 5,000 years. End-member modelling of grain sizes in accordance with lithogenic matter accumulation rates and event layer frequencies showed that arid conditions prevailed between 4,000 and 5,000 a BP while more humid conditions commenced around 2,000 ka BP in accordance with the Pacific ENSO record. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_894293 |
| institution | PANGAEA |
| language | en |
| publishDate | 2018 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Composition and grain size distribution of laminated sediment core SO130_275KL from northeastern Arabian Sea off Pakistan Gaye, Birgit KL; MAKRAN 2; Piston corer (BGR type); SO130; SO130_275KL; Sonne Laminated sediments of the continental slope off the Makran coast in the northern Arabian Sea are well-known climate archives and record productivity as well as supply of material from land. Here we studied sediment core 275KL off Pakistan in concert with sediment trap, dust and river samples in order to characterise and quantify land-derived material deposited in varves and event layers. We analysed grain sizes, mineral assemblages, bulk components, and stable isotopes (δ13C, δ18O) of carbonates. In winter, enhanced river discharge is the main source of lithogenic matter contributing the major amounts to the total annual sedimentation of the northern Arabian Sea. During the late summer season, lithogenic matter accumulation is slightly enhanced, probably carried along with the southeastward blowing Levar winds from the Balochistan and the Sistan Basins and the summer monsoon discharge maximum of perennial streams. C/N ratios and stable carbon and oxygen isotopes could not be used to distinguish between organic matter produced on land and in the ocean, whereas stable carbon and oxygen isotope ratios of carbonates suggest that sedimentation of event layers is dominated by direct inputs from land. Catastrophic denudation and storm events occur on average once every 50 years and lead to sedimentation rates that exceed the mean annual sedimentations of 983 g m-2 yr-1 by 6 to 10 times. Nevertheless, due to their rare occurrence they contributed only 7% to the total sedimentation during the last ca 5,000 years. End-member modelling of grain sizes in accordance with lithogenic matter accumulation rates and event layer frequencies showed that arid conditions prevailed between 4,000 and 5,000 a BP while more humid conditions commenced around 2,000 ka BP in accordance with the Pacific ENSO record. |
| title | Composition and grain size distribution of laminated sediment core SO130_275KL from northeastern Arabian Sea off Pakistan |
| topic | KL; MAKRAN 2; Piston corer (BGR type); SO130; SO130_275KL; Sonne |
| url | https://doi.org/10.1594/PANGAEA.894293 |