Chronology of the Palmer Deep site, Antarctic Peninsula: a Holocene palaeoenvironmental reference for the circum-Antarctic

Abstract

Palmer Deep sediment cores are used to produce the first high-resolution, continuous late Pleistocene to Holocene time-series from the Antarctic marine system. The sedimentary record is dated using accelerator mass spectrometer radiocarbon methods on acid insoluble organic matter and foraminiferal calcite. Fifty-four radiocarbon analyses are utilized in the dating which provides a calibrated timescale back to 13 ka BP. Reliability of resultant ages on organic matter is assured because duplicates produce a standard deviation from the surface age of less than laboratory error (i.e., +50 years). In addition, surface organic nmatter ages at the site are in excellent agreement with living calcite ages at the accepted reservoir age of -1260 years for the Antarctic Peninsula. Spectral analyses of the magnetic susceptibility record against the age model reveal unusually strong periodicity in the 400, -200 and 50-70 year frequency bands, similar to other high-resolution records from the Holocene but, so far, unique for the circum-Antarctic. Here we show that comparison to icecore records of specific climatic events (e.g., the 'Little Ice Age', Neoglacial, Hypsithermal, and the B0lling/Allerod to Younger Dryas transition) provides improved focus upon the relative timing of atmosphere/ocean changes between the northem anid southern high latitudes.

The sedimentary legacy of a palaeo-ice stream on the shelf of the southern Bellingshausen Sea: Clues to West Antarctic glacial history during the Late Quaternary

“…All other 14 C ages were obtained by dating the acid-insoluble organic fraction (AIO) of bulk sediment samples (cf. Licht et al, 1996Licht et al, , 1998Domack et al, 1999Domack et al, , 2001Licht and Andrews, 2002;Pudsey et al, 2006). We give the radiocarbon ages as conventional, i.e.…”

“…With the exception of site GC359, the down-core variability of the d 13 C org values at each individual core site is 1.1& (Table 1), which is comparable or less than at core sites from other parts of the Antarctic shelf (e.g. Harden et al, 1992;Domack et al, 1998Domack et al, , 1999Domack et al, , 2001Licht and Andrews, 2002;Ó Cofaigh et al, 2005a;Pudsey et al, 2006;Hemer et al, 2007;McKay et al, 2008;Hillenbrand et al, 2010). The d 13 C org composition of marine particulate organic substance typically ranges from À18& to À27& (e.g.…”

“…by dating the onset of seasonal openmarine sedimentation (e.g. Pudsey et al, 1994;Licht et al, 1996Licht et al, , 1999Domack et al, 1999Domack et al, , 2001Anderson et al, 2002;Licht and Andrews, 2002;Heroy and Anderson, 2005;Mosola and Anderson, 2006;McKay et al, 2008). These dates actually provide only minimum ages for ice-sheet retreat, but they are considered to be the most reliable radiocarbon ages available.…”

Antarctic Shallow Drilling Project provides key core samples

“…Core recovery was good (about 85%), except in the upper 20 meters of the section where soft, water-saturated sediments were encoun tered; this section can be retrieved in the future with a jumbo piston core. Paleoclimate reconstructions from these expanded Holocene sections at Maxwell Bay and Firth of Tay will complement a reconstruction from the Palmer Deep [Domack et al, 2001] on the Pacific side of the Antarctic Penin sula, and they will expand the geographic coverage of such records around the Penin sula region.…”

Chapter 5 Cenozoic Climate History from Seismic Reflection and Drilling Studies on the Antarctic Continental Margin

“…Domack et al, 2001aDomack et al, , b, 2005Brachfeld et al, 2003;Evans et al, 2005). These researchers infer that grounded ice converged into major ice streams and advanced to the shelf edge during the LGM, that the Prince Gustav Sound Ice Shelf collapsed and reformed in the mid-Holocene, and that the recent collapse of the Larsen B Ice Shelf is unprecedented during the Holocene.…”