Data Report: Physical Properties Relevant to Seismic Stratigraphic Studies, Continental Rise Sites 1095, 1096, and 1101, ODP Leg 178, Antarctic Peninsula

Volpi, V.; Camerlenghi, Angelo; Moerz, Tobias; Corubolo, Piero; Rebesco, Michele; Tinivella, Umberta

doi:10.2973/odp.proc.sr.178.228.2001

Cited by 13 publications

(15 citation statements)

References 1 publication

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“…The term is just used for better clarity. The maps of unit thickness were converted from milliseconds TWT into meters thickness applying the second-order polynomial regressions describing the relationship between TWT (in ms) and subbottom depth (in mbsf) at Sites 1095 and 1096 deduced by Volpi et al (2002).…”

Section: Resultsmentioning

confidence: 99%

“…This is most certainly due to the fact that (a) Rebesco et al (1997) studied sedimentation rates at a specific location at the gentle flank of Drift 7 on profile IT92-109, whereas I investigated the value for each whole sedimentary unit. This was done by using the results of ODP Leg 178 (Shipboard Scientific Party, 1999a,b;Volpi et al, 2002). I observe that sedimentation rates increase until unit M2 and show a slight decrease during unit M1.…”

Section: Seismic Stratigraphymentioning

confidence: 99%

“…Using the information supplied by ODP Leg 178 Sites 1095 and 1096 for Drift 7 (Shipboard Scientific Party, 1999a,b) and Site 1101 for Drift 4 (Shipboard Scientific Party, 1999c) the age model for the seismic units was refined. P-wave velocities supplied by Volpi et al (2002) were used to convert the geological information from depth into two-way traveltime. Moreover, the ages for the older not drilled units were ascertained on the basis of correlation with DSDP Site 325 (Tucholke et al, 1976) and ages of the underlying crust .…”

Section: Seismic Stratigraphymentioning

confidence: 99%

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Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Uenzelmann-Neben

2006

Marine Geology

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Understanding the processes and phases of deep-sea sediment drift formation is essential for a reconstruction of their evolution. This leads to a better understanding of the properties of oceanographic currents active during drift formation and in turn to information on the climatic conditions. A system of sediment drifts at the Antarctic Peninsula Pacific rise has been chosen to learn more about the Neogene evolution of both current systems and palaeo-climate in that area. Drift 7 was extensively surveyed (seismic and sampling), and two ODP Leg 178 sites were drilled there. Using this information, maps of reflectors depth and seismic unit thickness were compiled and interpreted regarding the controlling depositional processes. The depositional model shows an initially major along-slope sediment transport by a SW-setting bottom current (25-15 Ma), which deflected sediment supplied from the continental shelf. Between 15 Ma and 9.5 Ma down-slope transport took over as a result of the growth of the Antarctic Peninsula ice sheet. The SW setting bottom current appears to have broken down. Down-slope transport has decreased since 9.5 Ma, but a re-onset of the bottom current can only be observed since 5.3 Ma. The analysis has further shown that the nucleus of the drift is connected to a basement ridge. It is hence inferred that basement topography played a major role in the formation of this sediment drift.

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Section: Resultsmentioning

confidence: 99%

Section: Seismic Stratigraphymentioning

confidence: 99%

Section: Seismic Stratigraphymentioning

confidence: 99%

See 1 more Smart Citation

Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Uenzelmann-Neben

2006

Marine Geology

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“…The opal contents and the DBD at sites 1095, 1096 and 1101 were analyzed on different sets of samples (Barker et al, 1999;Hillenbrand and Fütterer, 2001). However, the downcore variability of the DBD values at the three sites is relatively small (Volpi et al, 2001). Therefore, we multiplied the opal content of a sample with the average DBD of the 10-metre long core that this sample was taken from, as well as with the corresponding LSR (instead of splicing the data sets for biogenic opal and DBD by resampling and multiplying them with the LSR, cf.…”

Section: Methodsmentioning

confidence: 99%

Polar stratification: A critical view from the Southern Ocean

Hillenbrand

Cortese

2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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Oceanic stratification represents an effective mechanism to reduce vertical mixing of the water column, thereby locking up carbon dioxide (CO 2 ) in the deep sea and preventing air-sea exchange of CO 2 . It has been proposed that enhanced stratification of the upper water column in polar oceans during late Cenozoic cooling episodes limited the upwelling of CO 2 -rich deep waters and thus CO 2 -release to the atmosphere, resulting in a net global drawdown of atmospheric CO 2 . Increased stratification in the Subarctic Northwest Pacific, during both the onset of Northern Hemisphere glaciation at 2.73 Ma and late Quaternary glacial periods, has been recently linked to enhanced ocean stratification south of the Antarctic Polar Front (APF) in the Pacific and Atlantic sectors of the Southern Ocean. Increased stratification of Southern Ocean surface waters was mainly deduced from a reduction of biological production during these cooling episodes, manifested by the decrease of geochemical proxies for productivity, such as biogenic opal and barium, in the marine sediment records. However, the records chosen from the Southern Ocean do not provide evidence for a more stratified upper water column, rather the observed decrease in biological productivity is likely to have resulted from an expansion of annual sea-ice coverage. The sediment records suggest that south of the APF in the Pacific and Atlantic sectors of the Southern Ocean, extensive sea ice may have contributed to the global CO 2 -drawdown during glacial periods, with hypothetical glacial increase of stratification in today's permanent open-ocean zone merely being an "add on" caused by this expansion.

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“…Downhole meas- urements of velocity at ocean drilling sites are very sparse and the use of short streamers during acquisition (due to ice conditions) often precludes the generation of a reliable velocity model. The study of Volpi et al [2001], for example, shows seismic interval velocities from stacking velocities that are very different to downhole velocities measured during ODP Leg 178. Because of this, we used an empirical relation [Carlson et al, 1986] ; the RMS error in these estimates is 26 m in depth.…”

Section: Twt [S] To Depth [M] Conversionmentioning

confidence: 99%

Gridded isopach maps from the South Pacific and their use in interpreting the sedimentation history of the West Antarctic continental margin

Scheuer

Gohl

Eagles

2006

Geochem Geophys Geosyst

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[1] We model sediment isopach grids for the southern Pacific margin of West Antarctica on the basis of a compilation of more than 10,000 km of single-channel and multichannel seismic reflection data and correlations with ocean drilling sites. Following recent seismic stratigraphic models, we differentiate two main sequences, the upper of which alone is defined by seismostratigraphic indications for frequent grounded ice advances to the shelf edge off West Antarctica. The subsequent modeling of sediment thickness grids allows us to compare the pre-glacially dominated and glacially dominated sedimentary development of the study area. On the basis of available age constraints from drilling sites, we assume the onset of accumulation of sediments on the continental rise that were supplied by frequent advances of grounding ice on the continental shelf to have occurred at about 10 Ma. The thickest glacial sediment accumulations occur in front of major glacial drainage outlets, i.e., Marguerite Trough on the western Antarctic Peninsula margin, Belgica Trough in the Bellingshausen Sea, and a depression on the inner and middle shelves off Pine Island Bay in the Amundsen Sea. Glacially dominated sedimentation rates of between 140 and 170 m/m.y. are calculated for these sites.

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Data Report: Physical Properties Relevant to Seismic Stratigraphic Studies, Continental Rise Sites 1095, 1096, and 1101, ODP Leg 178, Antarctic Peninsula

Cited by 13 publications

References 1 publication

Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Depositional patterns at Drift 7, Antarctic Peninsula: Along-slope versus down-slope sediment transport as indicators for oceanic currents and climatic conditions

Polar stratification: A critical view from the Southern Ocean

Gridded isopach maps from the South Pacific and their use in interpreting the sedimentation history of the West Antarctic continental margin

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