Synthetic Seismograms Linking ODP Sites to Seismic Profiles, Continental Rise and Shelf of Prydz Bay, Antarctica

Handwerger, D.; Cooper, Alan K.; O'Brien, PE; Williams, T. B.; Barr, S.; Dunbar, R. B.; Leventer, Amy; Jarrard, R. D.

doi:10.2973/odp.proc.sr.188.010.2004

Cited by 7 publications

(3 citation statements)

References 1 publication

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“…The drop at Site 1165 could be related to development of the Prydz Channel Fan as sediments brought down the Prydz Channel by Lambert Glacier became trapped in the fan rather than being entrained in offshore currents and deposited on the Wild Drift. This timing is consistent with seismic evidence that the onset of fan sedimentation occurred during the late Miocene to early Pliocene [ Shipboard Scientific Party , 2001a; Handwerger et al , 2003].…”

Section: Discussionsupporting

confidence: 87%

Neogene changes in Southern Ocean sedimentation based on mass accumulation rates at four continental margins

Handwerger

Jarrard

2003

Paleoceanography

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High‐resolution mass accumulation rates (MAR) were determined from lithologic logs based on downhole log and continuous core data for six sites at four continental margins around the Southern Ocean. Total MAR was calculated at Ocean Drilling Program (ODP) Site 1095 on the margin of the Antarctic Peninsula and ODP Site 1165 on the margin of Prydz Bay, Antarctica. Carbonate and noncarbonate (terrigenous) MAR were calculated for ODP Sites 1123 and 1124 east of New Zealand and Sites 1168 and 1172 west and southeast of Tasmania. Shifts in carbonate MAR are seen around Tasmania and New Zealand at 23 and 14 Ma, suggesting changes in deep water circulation and surface carbonate productivity at these times. Carbonate MAR dropped at Sites 1124 and 1168 at 23 Ma and increased at 14 Ma at Sites 1123, 1168, and 1172. The overall character of total MAR at Antarctic Sites 1095 and 1165 is a continual and relatively constant decrease in total MAR during the Neogene, with periods of stepwise decrease. One such decrease is seen at 14 Ma at Site 1165, coincident with increased carbonate MAR in New Zealand and Tasmania (Sites 1123, 1124, 1168 and 1172) and likely related to mid‐Miocene expansion of the East Antarctic Ice Sheet. Another step drop in total MAR is seen at ∼9 Ma at Site 1165, possibly reflecting diversion of sediment to a newly formed Prydz Channel fan.

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Section: Discussionsupporting

confidence: 87%

Neogene changes in Southern Ocean sedimentation based on mass accumulation rates at four continental margins

Handwerger

Jarrard

2003

Paleoceanography

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“…However, the age of the final transition to the polar ice sheet was not entirely resolved by the stratigraphic studies conducted for the Neogene continental shelf in the frame of ODP Leg 188 (Erohina et al 2004;O'Brien et al 2004;Handwerger et al 2004;Whitehead and Bohaty 2003). This age has been inferred progressively younger: from the middle-late Miocene (Cooper and O'Brien 2001), to the middle Miocene-Pleistocene , to the late Miocene or early Pliocene (Whitehead et al 2006).…”

Section: Introductionmentioning

confidence: 93%

New insights in the evolution of Antarctic glaciation from depth conversion of well-log calibrated seismic section of Prydz Bay

Volpi

Rebesco

Diviacco

2008

Int J Earth Sci (Geol Rundsch)

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The understanding of the evolution of the Antarctic Ice Sheet is crucial for the comprehension of the history of past global climate. The debate regarding the age of the transition to modern ''dry-and cold-based'' ice sheet after the Neogene polythermal conditions has taken place over more than 20 years. An evident change in the geometry of the depositional systems of the Prydz Bay continental margin demarked the initiation of the Prydz Channel Fan and has been inferred to correspond to this transition. The improvement in the age placement of this change contributes to unravel the last stages of the Antarctic glacial history. We predicted the spatial distribution of P-wave velocity data along both dip-and strike-oriented seismic profiles that intersect 3 Ocean Drilling Program (ODP) sites on the Prydz Bay continental shelf. We used this information to assist the correlation of the existing litho-and bio-stratigraphic information among the drilling sites and to produce an accurate geometric reconstruction of the Neogene shelf units through depth-migration of the seismic data. The revised stratigraphy that we obtained suggests an early late to late early Pliocene age for the seismic reflector at the base of the Prydz Channel Fan. This age, younger than previously proposed, is consistent with the age inferred for similar geometric changes identified in different Antarctic margins.

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“…Based on the synthetic seismograms, this boundary is tied to a surface at ~910 ms TWT in the Palmer '04 seismic line near Site 1166 and is penetrated at 267 mbsf in Hole 1166A. It occurs beyond the penetration depth of Hole 742A (Figure 2; Handwerger et al, 2004). Cretaceous pollen and spores, however, are reported within glacio-tectonized beds at the base of Hole 742A (Truswell, 1991;Hambrey et al, 1991), and interpretations of other seismic lines suggest that the pre-glacial to glacial surface lies about 50m below the total depth (TD) of Hole 742A (Erohina et al, 2004).…”

Section: Integrated Seismo-lithostratigraphymentioning

confidence: 99%

An Antarctic stratigraphic record of stepwise ice growth through the Eocene-Oligocene transition

Passchier

Ciarletta

Miriagos

et al. 2016

Geological Society of America Bulletin

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Earth's current icehouse phase began ~34 million years ago with the onset of major Antarctic glaciation at the Eocene-Oligocene Transition (EOT). Changes in ocean circulation and a decline in atmospheric greenhouse gas levels were associated with step-wise cooling and ice growth at southern high latitudes.The Antarctic cryosphere plays a critical role in the ocean-atmosphere system, but its early evolution is still poorly known. With a near-field record from Prydz Bay, Antarctica, we demonstrate that Antarctic ice growth was stepwise and had an earlier onset than previously suggested. Prydz Bay lies downstream of a major East Antarctic ice-sheet drainage system and its sedimentary records uniquely constrain the timing of ice-sheet advance onto the continental shelf. We investigate a detrital record extracted from three Ocean Drilling Program drill holes within a new depositional and chronological framework spanning the late Eocene to early Oligocene (~36-33 Ma). The chemical index of alteration (CIA) and the S-index, calculated from the major element geochemistry of bulk samples, yield estimates of chemical weathering intensities and mean annual temperature (MAT) on the East Antarctic continent. We document evidence for late Eocene mountain glaciation along with transient warm events at 35.8-34.8 Ma. From 34.4 Ma, associated with the EOT-1  18 O excursion, glaciers advanced into Prydz Bay, coincident with a decline in chemical weathering and temperature. We conclude that Antarctic continental ice growth commenced with the EOT-1 "precursor" glaciation, during a time of Subantarctic surface ocean cooling and a decline in atmospheric pCO 2 . These results call for dynamic high-latitude feedbacks that are currently poorly represented in Earth system models and emphasize the need for additional near-field glaciosedimentological, high-latitude SST, and pCO2 records across the EOT.

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Synthetic Seismograms Linking ODP Sites to Seismic Profiles, Continental Rise and Shelf of Prydz Bay, Antarctica

Cited by 7 publications

References 1 publication

Neogene changes in Southern Ocean sedimentation based on mass accumulation rates at four continental margins

Neogene changes in Southern Ocean sedimentation based on mass accumulation rates at four continental margins

New insights in the evolution of Antarctic glaciation from depth conversion of well-log calibrated seismic section of Prydz Bay

An Antarctic stratigraphic record of stepwise ice growth through the Eocene-Oligocene transition

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