| _version_ | 1867167865557221376 |
|---|---|
| author | Klöcker, Ralph Ganssen, Gerald M Jung, Simon J A Kroon, Dick Henrich, Rüdiger |
| author_facet | Klöcker, Ralph Ganssen, Gerald M Jung, Simon J A Kroon, Dick Henrich, Rüdiger |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | In order to better understand Late Quaternary pelagic aragonite preservation in the western Arabian Sea we have investigated a high-resolution sediment core 905 off Somalia. Pteropod preservation is enhanced in times of reduced monsoon-driven productivity, indicated by low amounts of Corg and low barium to aluminium (Ba/Al) ratios. All periods corresponding to Heinrich events in the North Atlantic are represented by maxima in shell preservation of the common pteropod Limacina inflata (LDX values <2, except for H5-equivalent with a poorer shell preservation, LDX >2.66). Good shell preservation is also found during stadials at 52.1-53.2, 36, 33.2, and 31.9 ka. Relative abundance of pteropods and their fragments in the coarse fraction reaches maxima during Marine Isotope Stage (MIS) 5.2, during time-equivalents of Heinrich events 4-6 and in stadials at not, vert, similar 53, not, vert, similar 42.5, and 41.4 ka. On longer time scales, the pteropod abundance corresponds to the 'Indo-Pacific carbonate preservation type' with poor preservation during interglacials and better preservation during glacials. Late MIS 5 to early MIS 4 sections (84.1-64.8 ka) and the Late Holocene interval (6.5–0 ka) of core 905 contain only traces of pteropods. The early Holocene (9.2-6.5 ka) part is characterized by low pteropod amounts. Between 64.8 and 43.4 ka strong fluctuations occur and an intermediate average relative pteropod abundance is revealed. Between 43.4 and 9.2 ka the highest amounts in relative pteropod abundance in core 905 are observed. Besides the regional monsoonal influence on deepwater chemistry, changes in deepwater circulation occurring on glacial/interglacial and stadial/interstadial time scales might have affected pteropod preservation. However, it remains elusive whether 1) deep water formation in the Arabian Sea, 2) inflow of Glacial North Atlantic Intermediate Water or 3) change in water mass properties of the Circumpolar Deep Water (which is the water mass currently bathing this site) contributed to the observed pteropod preservation pattern. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_328911 |
| institution | PANGAEA |
| language | en |
| publishDate | 2005 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Age, pteropoda counts and Limacina dissolution index of sediment core NIOP-C2_905_BC Klöcker, Ralph Ganssen, Gerald M Jung, Simon J A Kroon, Dick Henrich, Rüdiger AGE; Calculated, see reference(s); Center for Marine Environmental Sciences; Counting 125-500 µm fraction; DEPTH, sediment/rock; Limacina dissolution index; MARUM; Netherlands Indian Ocean Programme; NIOP; NIOP-C2; NIOP-C2_905_PC; PC; Piston corer; Pteropoda; Pteropoda fragmentation ratio; Pteropoda fragments; Tyro In order to better understand Late Quaternary pelagic aragonite preservation in the western Arabian Sea we have investigated a high-resolution sediment core 905 off Somalia. Pteropod preservation is enhanced in times of reduced monsoon-driven productivity, indicated by low amounts of Corg and low barium to aluminium (Ba/Al) ratios. All periods corresponding to Heinrich events in the North Atlantic are represented by maxima in shell preservation of the common pteropod Limacina inflata (LDX values <2, except for H5-equivalent with a poorer shell preservation, LDX >2.66). Good shell preservation is also found during stadials at 52.1-53.2, 36, 33.2, and 31.9 ka. Relative abundance of pteropods and their fragments in the coarse fraction reaches maxima during Marine Isotope Stage (MIS) 5.2, during time-equivalents of Heinrich events 4-6 and in stadials at not, vert, similar 53, not, vert, similar 42.5, and 41.4 ka. On longer time scales, the pteropod abundance corresponds to the 'Indo-Pacific carbonate preservation type' with poor preservation during interglacials and better preservation during glacials. Late MIS 5 to early MIS 4 sections (84.1-64.8 ka) and the Late Holocene interval (6.5–0 ka) of core 905 contain only traces of pteropods. The early Holocene (9.2-6.5 ka) part is characterized by low pteropod amounts. Between 64.8 and 43.4 ka strong fluctuations occur and an intermediate average relative pteropod abundance is revealed. Between 43.4 and 9.2 ka the highest amounts in relative pteropod abundance in core 905 are observed. Besides the regional monsoonal influence on deepwater chemistry, changes in deepwater circulation occurring on glacial/interglacial and stadial/interstadial time scales might have affected pteropod preservation. However, it remains elusive whether 1) deep water formation in the Arabian Sea, 2) inflow of Glacial North Atlantic Intermediate Water or 3) change in water mass properties of the Circumpolar Deep Water (which is the water mass currently bathing this site) contributed to the observed pteropod preservation pattern. |
| title | Age, pteropoda counts and Limacina dissolution index of sediment core NIOP-C2_905_BC |
| topic | AGE; Calculated, see reference(s); Center for Marine Environmental Sciences; Counting 125-500 µm fraction; DEPTH, sediment/rock; Limacina dissolution index; MARUM; Netherlands Indian Ocean Programme; NIOP; NIOP-C2; NIOP-C2_905_PC; PC; Piston corer; Pteropoda; Pteropoda fragmentation ratio; Pteropoda fragments; Tyro |
| url | https://doi.org/10.1594/PANGAEA.328911 |