Deciphering tectonic phases of the Amundsen Sea Embayment shelf, West Antarctica, from a magnetic anomaly grid

Gohl, Karsten; Denk, Astrid; Eagles, Graeme; Wobbe, Florian

doi:10.1016/j.tecto.2012.06.036

Cited by 38 publications

(79 citation statements)

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“…Seismic data revealed progradational and aggradational deposition on the outer shelf and slope of the ASE probably since the mid-Miocene (e.g., Nitsche et al, 1997Nitsche et al, , 2000Hochmuth and Gohl, 2013;Gohl et al, 2013a). Numerous unconformities within strata on the shelf document frequent advance and retreat of grounded ice from the late Miocene until the Pliocene/Pleistocene according to the stratigraphic age model by Gohl et al (2013a).…”

Section: Hypothesis H4: Major Wais Advances Onto the Middle And Outermentioning

confidence: 96%

“…Numerous unconformities within strata on the shelf document frequent advance and retreat of grounded ice from the late Miocene until the Pliocene/Pleistocene according to the stratigraphic age model by Gohl et al (2013a). The preservation of buried grounding-zone wedges in the Pliocene/Pleistocene sequence on the outer ASE shelf is consistent with prolonged continuous accumulation of (glaci-)marine sediments in an open-marine setting, probably during a long interglacial period with a significantly reduced WAIS, as observed on the Ross Sea shelf during the early Pliocene.…”

Section: Hypothesis H4: Major Wais Advances Onto the Middle And Outermentioning

confidence: 99%

“…Thick gray lines mark existing marine multi-and single-channel seismic profiles collected during six ship expeditions from 1994 to 2010 (e.g., Gohl et al, 2013b). Orange line marks the boundary between the outcropping basement of the inner shelf and the sedimentary basin of the middle shelf Gohl et al, 2013aGohl et al, , 2013b. Figure F2.…”

Section: Expedition Scientists and Scientific Participantsmentioning

confidence: 99%

“…(d) Figure F5. A. Seismic stratigraphic model of the eastern ASE shelf with sedimentary Units ASS-1 to ASS-6 and major Unconformities ASS-u1 to ASS-u5 (modified from Gohl et al, 2013a). Units ASS1-ASS4 correspond to sedimentary units of the ASE continental rise according to Uenzelmann-Neben and Gohl (2012).…”

Section: Pliocenementioning

confidence: 99%

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Gohl¹,

Wellner²,

Klaus³

2017

International Ocean Discovery Program Scientific Prospectus

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The West Antarctic Ice Sheet (WAIS) is largely marine based and thus highly sensitive to both climatic and oceanographic changes. Therefore, the WAIS has likely had a very dynamic history over the last several million years. A complete collapse of the WAIS would result in a global sea level rise of 3.3-4.3 m, yet the world's scientific community is not able to predict its future behavior. Moreover, knowledge about past behavior of the WAIS is poor, in particular during geological times with climatic conditions similar to those expected for the near and distant future. Reconstructions and quantifications of partial or complete WAIS collapses in the past are urgently needed for constraining and testing ice sheet models that aim to predict future WAIS behavior and the potential contribution of the WAIS to global sea level rise. Large uncertainties exist regarding the chronology, extent, rates, and spatial and temporal variability of past advances and retreats of the WAIS across the continental shelves. These uncertainties largely result from the fundamental lack of data from drill cores recovered proximal to the WAIS. The continental shelf and rise of the Amundsen Sea are prime targets for drilling because the records are expected to yield archives of pure WAIS dynamics unaffected by other ice sheets and the WAIS sector draining into the Amundsen Sea Embayment (ASE) currently experiences the largest ice loss in Antarctica (Paolo et al., 2015).We propose a series of drill sites for the ASE shelf where seismic data reveal seaward-dipping sedimentary sequences that span from the preglacial depositional phase to the most recent glacial periods. Our strategy is to drill a transect from the oldest sequences close to the bedrock/basin boundary at the middle-inner shelf transition to the youngest sequences on the outer shelf in the eastern ASE. If the eastern ASE is inaccessible due to sea ice cover, a similar transect of sites can be drilled on the western ASE. The core transect will provide a detailed history of the glacial cycles in the Amundsen Sea region and allow comparison to the glacial history from the Ross Sea sector. In addition, deep-water sites on the continental rise of the Amundsen Sea are selected for recovering continuous records of glacially transported sediments and detailed archives of climatic and oceanographic changes throughout glacial-interglacial cycles. We will apply a broad suite of analytical techniques, including multiproxy analyses, to address our objectives of reconstructing the onset of glaciation in the greenhouse to icehouse transition, processes of dynamic ice sheet behavior during the Neogene and Quaternary, and ocean conditions associated with the glacial cycles.The five principal objectives of Expedition 379 are as follows:1. To reconstruct the glacial history of West Antarctica from the Paleogene to recent times and the dynamic behavior of the WAIS during the Neogene and Quaternary, especially possible partial or full WAIS collapses, and the WAIS contribution to past sea level...

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Section: Hypothesis H4: Major Wais Advances Onto the Middle And Outermentioning

confidence: 96%

Section: Hypothesis H4: Major Wais Advances Onto the Middle And Outermentioning

confidence: 99%

Section: Expedition Scientists and Scientific Participantsmentioning

confidence: 99%

Section: Pliocenementioning

confidence: 99%

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Gohl¹,

Wellner²,

Klaus³

2017

International Ocean Discovery Program Scientific Prospectus

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“…Recent studies of the ASE presented by Weigelt et al (2009), Gohl et al (2007Gohl et al ( , 2013a, Wobbe et al (2012) and Kalberg and Gohl (2014) reveal the embayment to be underlain by multi-staged rifted, extremely stretched and magmatically-underplated continental crust which is overprinted by several tectonic lineaments. The data have been interpreted to indicate a set of rift basins that formed (Fretwell et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Rift processes and crustal structure of the Amundsen Sea Embayment, West Antarctica, from 3D potential field modelling

et al. 2015

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Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

Cochran

Tinto

Bell

2015

Geochem Geophys Geosyst

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Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5–1.7 with 80–100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts.Key Points:Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise

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Deciphering tectonic phases of the Amundsen Sea Embayment shelf, West Antarctica, from a magnetic anomaly grid

Cited by 38 publications

References 34 publications

Untitled

Untitled

Rift processes and crustal structure of the Amundsen Sea Embayment, West Antarctica, from 3D potential field modelling

Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

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