Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp
During four expeditions with RV "Polarstern" at the continental margin of the southern Weddell Sea, profiling and geological sampling were carried out. A detailed bathymetric map was constructed from echo-sounding data. Sub-bottom profiles, classified into nine echotypes, have been mapped...
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Format: | Article in Journal/Newspaper |
Language: | English |
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PANGAEA - Data Publisher for Earth & Environmental Science
1991
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Online Access: | https://dx.doi.org/10.1594/pangaea.729620 https://doi.pangaea.de/10.1594/PANGAEA.729620 |
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ftdatacite:10.1594/pangaea.729620 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Giant box corer Dredge Gravity corer Kiel type Multiboxcorer ANT-I/2 ANT-II/4 ANT-III/3 ANT-IV/3 ANT-V/4 ANT-VI/3 Polarstern Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo |
spellingShingle |
Giant box corer Dredge Gravity corer Kiel type Multiboxcorer ANT-I/2 ANT-II/4 ANT-III/3 ANT-IV/3 ANT-V/4 ANT-VI/3 Polarstern Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo Melles, Martin Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp |
topic_facet |
Giant box corer Dredge Gravity corer Kiel type Multiboxcorer ANT-I/2 ANT-II/4 ANT-III/3 ANT-IV/3 ANT-V/4 ANT-VI/3 Polarstern Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo |
description |
During four expeditions with RV "Polarstern" at the continental margin of the southern Weddell Sea, profiling and geological sampling were carried out. A detailed bathymetric map was constructed from echo-sounding data. Sub-bottom profiles, classified into nine echotypes, have been mapped and interpreted. Sedimentological analyses were carried out on 32 undisturbed box grab surface samples, as well as on sediment cores from 9 sites. Apart from the description of the sediments and the investigation of sedimentary structures on X-radiographs the following characteristics were determined: grain-size distributions; carbonate and Corg content; component distibutions in different grain-size fractions; stable oxygen and carbon isotopes in planktic and, partly, in benthic foraminifers; and physical properties. The stratigraphy is based On 14C-dating, oxygen isotope Stages and, at one site, On paleomagnetic measurements and 230Th-analyses The sediments represent the period of deposition from the last glacial maximum until recent time. They are composed predominantly of terrigenous components. The formation of the sediments was controlled by glaciological, hydrographical and gravitational processes. Variations in the sea-ice coverage influenced biogenic production. The ice sheet and icebergs were important media for sediment transport; their grounding caused compaction and erosion of glacial marine sediments on the outer continental shelf. The circulation and the physical and chemical properties of the water masses controlled the transport of fine-grained material, biogenic production and its preservation. Gravitational transport processes were the inain mode of sediment movements on the continental slope.The continental ice sheet advanced to the shelf edge and grounded On the sea-floor, presumably later than 31,000 y.B.P. This ice movement was linked with erosion of shelf sediments and a very high sediment supply to the upper continental slope from the adiacent southern shelf. The erosional surface On the shelf is documented in the sub-bottom profiles as a regular, acoustically hard reflector. Dense sea-ice coverage above the lower and middle continental slope resulted in the almost total breakdown of biogenic production. Immediately in front of the ice sheet, above the upper continental slope, a <50 km broad coastal polynya existed at least periodically. Biogenic production was much higher in this polynya than elsewhere. Intense sea-ice formation in the polynya probably led to the development of a high salinity and, consequently, dense water mass, which flowed as a stream near bottom across the continental slope into the deep sea, possibly contributing to bottom water formation. The current velocities of this water mass presumably had seasonal variations. The near-bottom flow of the dense water mass, in combination with the gravity transport processes that arose from the high rates of sediment accumulation, probably led to erosion that progressed laterally from east to West along a SW to NE-trending, 200 to 400 m high morphological step at the continental slope.During the period 14,000 to 13,000 y.B.P., during the postglacial temperature and sea-level rise, intense changes in the environmental conditions occured. Primarily, the ice masses on the outer continental shelf started to float. Intense calving processes resulted in a rapid retreat of the ice edge to the south. A consequence of this retreat was, that the source area of the ice-rafted debris changed from the adjacent southern shelf to the eastern Weddell Sea. As the ice retreated, the gravitational transport processes On the continental slope ceased. Soon after the beginning of the ice retreat, the sea-ice coverage in the whole research area decreased. Simultaneously, the formation of the high salinity dense bottom water ceased, and the sediment composition at the continental slope then became influenced by the water masses of the Weddell Gyre.The formation of very cold Ice Shelf Water (ISW) started beneath the southward retreating Filchner-Ronne Ice Shelf somewhat later than 12,000 y.B.P. The ISW streamed primarily with lower velocities than those of today across the continental slope, and was conducted along the erosional step on the slope into the deep sea. At 7,500 y.B.P., the grounding line of the ice masses had retreated > 400 km to the south. A progressive retreat by additional 200 to 300 km probably led to the development of an Open water column beneath the ice south of Berkner Island at about 4,000 y.B.P. This in turn may have led to an additional ISW, which had formed beneath the Ronne Ice Shelf, to flow towards the Filcher Ice Shelf. As a result, increased flow of ISW took place over the continental margin, possibly enabling the ISW to spill over the erosional step On the upper continental slope towards the West. Since that time, there is no longer any documentation of the ISW in the sedimentary Parameters on the lower continental slope. There, recent sediments reflect the lower water masses of the Weddell Gyre. The sea-ice coverage in early Holocene time was again so dense that biogenic production was significantly restricted. |
format |
Article in Journal/Newspaper |
author |
Melles, Martin |
author_facet |
Melles, Martin |
author_sort |
Melles, Martin |
title |
Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp |
title_short |
Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp |
title_full |
Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp |
title_fullStr |
Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp |
title_full_unstemmed |
Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp |
title_sort |
sedimentology at the continental margin of the southern weddell sea, supplement to: melles, martin (1991): paläoglaziologie und paläozeanographie im spätquartär am kontinentalrand des südlichen weddellmeeres, antarktis (late quaternary paleoglaciology and paleoceanography at the continental margin of the southern weddell sea, antarctica). berichte zur polarforschung = reports on polar research, 81, 190 pp |
publisher |
PANGAEA - Data Publisher for Earth & Environmental Science |
publishDate |
1991 |
url |
https://dx.doi.org/10.1594/pangaea.729620 https://doi.pangaea.de/10.1594/PANGAEA.729620 |
long_lat |
ENVELOPE(-48.117,-48.117,-79.333,-79.333) ENVELOPE(-61.000,-61.000,-78.500,-78.500) |
geographic |
Berkner Island Ronne Ice Shelf Weddell Weddell Sea |
geographic_facet |
Berkner Island Ronne Ice Shelf Weddell Weddell Sea |
genre |
Antarc* Antarctica Antarktis* Berkner Island Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ronne Ice Shelf Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctica Antarktis* Berkner Island Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ronne Ice Shelf Sea ice Weddell Sea |
op_relation |
https://dx.doi.org/10.2312/bzp_0081_1991 |
op_rights |
Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/pangaea.729620 https://doi.org/10.2312/bzp_0081_1991 |
_version_ |
1766257703533936640 |
spelling |
ftdatacite:10.1594/pangaea.729620 2023-05-15T13:52:53+02:00 Sedimentology at the continental margin of the southern Weddell Sea, supplement to: Melles, Martin (1991): Paläoglaziologie und Paläozeanographie im Spätquartär am Kontinentalrand des südlichen Weddellmeeres, Antarktis (Late Quaternary paleoglaciology and paleoceanography at the continental margin of the southern Weddell Sea, Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 81, 190 pp Melles, Martin 1991 application/zip https://dx.doi.org/10.1594/pangaea.729620 https://doi.pangaea.de/10.1594/PANGAEA.729620 en eng PANGAEA - Data Publisher for Earth & Environmental Science https://dx.doi.org/10.2312/bzp_0081_1991 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 CC-BY Giant box corer Dredge Gravity corer Kiel type Multiboxcorer ANT-I/2 ANT-II/4 ANT-III/3 ANT-IV/3 ANT-V/4 ANT-VI/3 Polarstern Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo Collection article Supplementary Collection of Datasets 1991 ftdatacite https://doi.org/10.1594/pangaea.729620 https://doi.org/10.2312/bzp_0081_1991 2021-11-05T12:55:41Z During four expeditions with RV "Polarstern" at the continental margin of the southern Weddell Sea, profiling and geological sampling were carried out. A detailed bathymetric map was constructed from echo-sounding data. Sub-bottom profiles, classified into nine echotypes, have been mapped and interpreted. Sedimentological analyses were carried out on 32 undisturbed box grab surface samples, as well as on sediment cores from 9 sites. Apart from the description of the sediments and the investigation of sedimentary structures on X-radiographs the following characteristics were determined: grain-size distributions; carbonate and Corg content; component distibutions in different grain-size fractions; stable oxygen and carbon isotopes in planktic and, partly, in benthic foraminifers; and physical properties. The stratigraphy is based On 14C-dating, oxygen isotope Stages and, at one site, On paleomagnetic measurements and 230Th-analyses The sediments represent the period of deposition from the last glacial maximum until recent time. They are composed predominantly of terrigenous components. The formation of the sediments was controlled by glaciological, hydrographical and gravitational processes. Variations in the sea-ice coverage influenced biogenic production. The ice sheet and icebergs were important media for sediment transport; their grounding caused compaction and erosion of glacial marine sediments on the outer continental shelf. The circulation and the physical and chemical properties of the water masses controlled the transport of fine-grained material, biogenic production and its preservation. Gravitational transport processes were the inain mode of sediment movements on the continental slope.The continental ice sheet advanced to the shelf edge and grounded On the sea-floor, presumably later than 31,000 y.B.P. This ice movement was linked with erosion of shelf sediments and a very high sediment supply to the upper continental slope from the adiacent southern shelf. The erosional surface On the shelf is documented in the sub-bottom profiles as a regular, acoustically hard reflector. Dense sea-ice coverage above the lower and middle continental slope resulted in the almost total breakdown of biogenic production. Immediately in front of the ice sheet, above the upper continental slope, a <50 km broad coastal polynya existed at least periodically. Biogenic production was much higher in this polynya than elsewhere. Intense sea-ice formation in the polynya probably led to the development of a high salinity and, consequently, dense water mass, which flowed as a stream near bottom across the continental slope into the deep sea, possibly contributing to bottom water formation. The current velocities of this water mass presumably had seasonal variations. The near-bottom flow of the dense water mass, in combination with the gravity transport processes that arose from the high rates of sediment accumulation, probably led to erosion that progressed laterally from east to West along a SW to NE-trending, 200 to 400 m high morphological step at the continental slope.During the period 14,000 to 13,000 y.B.P., during the postglacial temperature and sea-level rise, intense changes in the environmental conditions occured. Primarily, the ice masses on the outer continental shelf started to float. Intense calving processes resulted in a rapid retreat of the ice edge to the south. A consequence of this retreat was, that the source area of the ice-rafted debris changed from the adjacent southern shelf to the eastern Weddell Sea. As the ice retreated, the gravitational transport processes On the continental slope ceased. Soon after the beginning of the ice retreat, the sea-ice coverage in the whole research area decreased. Simultaneously, the formation of the high salinity dense bottom water ceased, and the sediment composition at the continental slope then became influenced by the water masses of the Weddell Gyre.The formation of very cold Ice Shelf Water (ISW) started beneath the southward retreating Filchner-Ronne Ice Shelf somewhat later than 12,000 y.B.P. The ISW streamed primarily with lower velocities than those of today across the continental slope, and was conducted along the erosional step on the slope into the deep sea. At 7,500 y.B.P., the grounding line of the ice masses had retreated > 400 km to the south. A progressive retreat by additional 200 to 300 km probably led to the development of an Open water column beneath the ice south of Berkner Island at about 4,000 y.B.P. This in turn may have led to an additional ISW, which had formed beneath the Ronne Ice Shelf, to flow towards the Filcher Ice Shelf. As a result, increased flow of ISW took place over the continental margin, possibly enabling the ISW to spill over the erosional step On the upper continental slope towards the West. Since that time, there is no longer any documentation of the ISW in the sedimentary Parameters on the lower continental slope. There, recent sediments reflect the lower water masses of the Weddell Gyre. The sea-ice coverage in early Holocene time was again so dense that biogenic production was significantly restricted. Article in Journal/Newspaper Antarc* Antarctica Antarktis* Berkner Island Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ronne Ice Shelf Sea ice Weddell Sea DataCite Metadata Store (German National Library of Science and Technology) Berkner Island ENVELOPE(-48.117,-48.117,-79.333,-79.333) Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) Weddell Weddell Sea |