From 1 - 10 / 17
  • This data were collected as part of the Ocean Drilling Program. All data were collected on Leg 119. The cruise for Leg 119 began at Port Louis Harbor, Mauritius, and finished at the Port of Fremantle, Australia. The objective was to complete a transect, along with Leg 120, to study the Late Cretaceous to Holocene palaeoclimatic history of East Antarctic, tectonic history of the Kerguelen Plateau, and the late Mesozoic rifting history of the Indian plate from East Antarctica. Samples are sediments. Good calibration standards for sediments not available. More information can be obtained from the Ocean Drilling Program website. The data obtained from the drilling is available on the Ocean Drilling Program website (see Download Paleontology Data). From the abstract of one of the papers: The timing and nature of the initiation of the Antarctic Ice Sheet is the subject of considerable discussion. Before Leg 119, the earliest known unequivocal Cenozoic glacial sediments were discovered in a Lower Oligocene sequence from the Ross Sea. Quartz grains of Eocene age from the Subantarctic Pacific Ocean were inferred from their grain texture to be ice-rafted. Previous results obtained by Leg 113 in the Weddell Sea indicate that glaciation at sea level first occurred during the late early Oligocene on East Antarctica and during the late Miocene on western Antarctica. Our new results show that glaciation is present during the earliest Oligocene and possibly the late Miocene.

  • Metadata record for data from ASAC Project 2393 See the link below for public details on this project. ---- Public Summary from Project ---- This project seeks to monitor Holocene-Quaternary variability of Antarctic bottom water outflow at a known deep pathway (east flank of Kerguelen Plateau) into a major ocean basin. Specifically, we can address the question of how sea-ice, frontal dynamics and SST variability are related to bottom-water production. Taken from the 2003-2004 Progress Report Two researchers from the ACE CRC and IASOS, Dr. Will Howard and Honours student Joanne Naylor, participated in a cruise to the Southern Kerguelen Plateau region in January-February 2004. The objectives were to carry out swath bathymetric mapping, subbottom profiling (using a 3.5 kHz echosounder), and coring, aboard the Japanese research vessel Mirai. We were successful in carrying out acoustic profiling and mapping in previously unmapped regions of the Southeast Indian Ridge and in the Labuan Basin area of Southern Kerguelen Plateau. Acoustic data have already been provided to Geoscience Australia, where these data will be incorporated into existing databases of bathymetry and bottom character of this (potential) part of the Australian Marine Jurisdiction. In addition we recovered two piston cores, one each from the SE Indian Ridge area and Kerguelen Plateau, as well as multicores (recovery of sediment-water interface). Inclement weather prevented us from recovering cores from all the suitable coring sites we identified, but we now have acoustic survey data in unprecedented detail and resolution to support future sampling efforts. The cores we recovered consist of pelagic sediments as follows: Split surfaces of archive half sections were exposed and lithological and sedimentological features were described using printed visual core description (VCD) sheets On MR03-K04 Leg 6, ODP-style nomenclature for lithological description (e.g., Mazzullo et al., 1988) was adopted. Results from smear slides, coarse-fraction microfossil observations were combined to construct summarised lithologic columns. This information was also confirmed by the later inspection of soft X-radiographs. Smear-slide descriptions and sieve sample also provide preliminary biostratigraphic estimates of base ages for the piston cores. Results In general, the sediments at both sites are composed of homogenous fine-grained pelagic sediments with extensive, though varying, bioturbation throughout. The lithological and sedimentological features are summarised as graphic columns with short notes, including a legend of symbols and lithologic patterns (Figures D-2-1, D-2-2, D-2-3). Digitised versions of individual VCD sheets and scanned soft X-radiographs used for constructing graphic columns are archived in the Appendix to this report. Southeast Indian Ridge (41 degrees 33.07'S, 90 degrees24,39 E, water depth: 2,913 m) The sediments from MC-05 and PC-05 from the northern flank of Southeast Indian Ridge are dominated by foraminifer-bearing nannofossil ooze. Foraminifera and nannofossils are abundant and well-preserved throughout the core. A qualitative analysis of the planktonic foraminiferal faunas from sieve samples taken at the base of the piston core and the top of the multicore show a diverse assemblage typical of coretops in the Southern Indian Ocean near the modern position of the Subtropical Front Zone, with abundant Globorotalia inflata, Globigerina bulloides, Globigerinita glutinata, and dextral Neogloboquadrina pachyderma (e.g. Howard and Prell, 1992 and 1994). The diatom Hemidiscus karsteni appears to be present in the core base whereas the radiolarian Stylatractus universus appears to be absent. These suggest a base age for PC-05 older that late Marine Isotope Stage (MIS) 7 (approx. 194 ka BP) and younger than late MIS 12 (approx 423 ka BP)*. Flow-in is severe in Sections IX and X and the core catcher of PC-05 (i.e. approx. the bottom 1.5 meters of the core). Comparison with the multicore indicates that the top of the piston core is also moderately disturbed by the piston action. Kerguelen Plateau (53 degrees 48.15'S, 81 degrees 52.75'E, water depth: 2,557 m) The sediments from MC-06 and PC-06 from Labuan Basin, Kerguelen Plateau are dominated by radiolarian-bearing diatom ooze with dispersed foraminifera, detrital grains, and rare nannofossils. Dispersed sand-to-gravel sized rock fragments are present in the core, indicating intermittent ice-rafted debris deposition. The soft X-radiographs similarly show the alternation of almost pure biogenic ooze with more clay-rich oozes with dispersed detrital grains. Though the core is bioturbated to some extent throughout its length, 1-2 cmscale laminations occur in Sections 3-8. Foraminifera present through core in varying states of preservation; nannofossils intermittently present. The planktonic foraminiferal assemblages are typical of coretops in the Subantarctic and Polar Front Zones, dominated by sinistral Neogloboquadrina pachyderma, Globigerina quinqueloba , and G. bulloides, with lesser contributions from globorotalids like Globorotalia crassiformis and and G. inflata. H. karsteni appears to be present from Section 6 (500 cm bsf) down, and abundant in Section 8, from 86 cm down (from approx. 786 cm bsf). The planktonic foraminifer G. crassiformis is present in the base. S. universus appears to be absent throughout the core. This preliminary estimate of the biostratigraphy suggests a base age for PC-06 older that late MIS 9 and younger than MIS 12 (i.e. between approx. 423 and 300 ka BP). The top 176 cm of this core are severely disturbed, being 'washed' during core recovery by water trapped in the core barrel by the stuck piston. All cores were also logged for geophysical properties and optical reflectance (an index of sediment properties). Also see the JAMSTEC (Japan Agency for Marine-Earth Science and Technology) site for more information.

  • Metadata record for data from ASAC Project 2534 See the link below for public details on this project. The Holocene sea-ice project brings together for the first time, records from the Antarctic continent and deep sea sediments that will allow us to calibrate three sea-ice extent surrogates, validate their use in contrast to satellite observations and explore climatic influence on the physio-ecological environment over the last 10,000 years. Taken from the 2004-2005 Progress Report: Progress Objectives: Our objective is to instigate synthesis between deep sea and continental ice core records of Antarctic sea ice variability over the Holocene (last 10,000 yrs BP). The relevance of this novel evaluation is three-fold: - To appraise for the first time the relationships between proxy sea ice predictions beyond the instrumental record from the land and sea. - To assess variability differences and similarities from the various records that can then be used to probe the dynamics of the climate/environmental system in the East Antarctic sector. - To provide insights on the ecological response sea ice plays through the Holocene. Public summary of the season progress: Basic analysis of samples from Core E27-23 have been complete except for seven new samples from near the top of the core. This includes counts of diatoms, foraminifera, ice-rafted debris, volcanic glass. A greater variety of parameters is available than expected. Dramatic downhole changes represent oceanographic changes over last 25 000 years at the site including in evidence for carbonate dissolution and water temperature. Now needs statistical analysis of diatom data, extra radiocarbon dates and integration with data from Law Dome ice-core.

  • This data were collected as part of the Ocean Drilling Program. All data were collected on Leg 119. The cruise for Leg 119 began at Port Louis Harbor, Mauritius, and finished at the Port of Fremantle, Australia. The objective was to complete a transect, along with Leg 120, to study the Late Cretaceous to Holocene palaeoclimatic history of East Antarctic, tectonic history of the Kerguelen Plateau, and the late Mesozoic rifting history of the Indian plate from East Antarctica. Samples are sediments. Good calibration standards for sediments not available. More information can be obtained from the Ocean Drilling Program website. The data obtained from the drilling is available on the Ocean Drilling Program website (see Download Paleontology Data). From the abstract of one of the papers: During Leg 119 of the Ocean Drilling Program, between December 1987 and February 1988, six holes were drilled in the Kerguelen Plateau, southern Indian Ocean, and five in Prydz Bay at the mouth of the Amery Ice Shelf, on the East Antarctic continental shelf. The Prydz Bay holes, reported here, form a transect from the inner shelf to the continental slope, recording a prograding sequence of possible Late Palaeozoic to Eocene to Quaternary glacially dominated sediments. This extends the known onset of large-scale glaciation of Antarctica back to about 36-40 million years ago, the sedimentary record suggesting that a fully developed East Antarctic Ice Sheet reached the coast at Prydz Bay at this time, and was more extensive than the present sheet. Subsequent glacial history is complex, with the bulk of sedimentation in the outer shelf taking place close to the grounding line of an extended Amery Ice Shelf. However, breaks in the record and intervals of no recovery may hide evidence of periods of glacial retreat.

  • Metadata record for data from ASAC Project 2237 See the link below for public details on this project. Two excel spreadsheets are available for download from the provided URL. Taken from the 1997-1998 Progress Report for this project: INAA (instrumental neutron activation analysis) analyses have been made of subsamples of each OSL (Optically stimulated luminescence) sample, for dosimetry calculation. The samples were then dated at Royal Holloway, University of London (RHUL) which is the worlds leading lab for this work. Two very significant findings were made: (i) That the OSL technique works, and is reliable in Antarctica. These are the first OSL dates from Antarctica; (ii) The overriding hypothesis of Colhoun et al. (ASAC 926) has been vindicated: that Bunger Hills was not fully glaciated at the last glacial maximum.

  • Reconstructed sea spray and minerogenic data for a 12,000 year lake sediment record from Emerald Lake, Macquarie Island. Proxies are based on biological (diatoms) and geochemical (micro x-ray fluorescence and hyperspectral imaging) indicators. Data correspond to the figures in: Saunders et al. 2018 Holocene dynamics of the Southern Hemisphere westerly winds and possible links to CO2 outgassing. Nature Geoscience 11:650-655. doi.org/10.1038/s41561-018-0186-5. Detailed supplementary information: https://static-content.springer.com/esm/art%3A10.1038%2Fs41561-018-0186-5/MediaObjects/41561_2018_186_MOESM1_ESM.pdf Abstract: The Southern Hemisphere westerly winds (SHW) play an important role in regulating the capacity of the Southern Ocean carbon sink. They modulate upwelling of carbon-rich deep water and, with sea ice, determine the ocean surface area available for air–sea gas exchange. Some models indicate that the current strengthening and poleward shift of these winds will weaken the carbon sink. If correct, centennial- to millennial-scale reconstructions of the SHW intensity should be linked with past changes in atmospheric CO2, temperature and sea ice. Here we present a 12,300-year reconstruction of wind strength based on three independent proxies that track inputs of sea-salt aerosols and minerogenic particles accumulating in lake sediments on sub-Antarctic Macquarie Island. Between about 12.1 thousand years ago (ka) and 11.2 ka, and since about 7 ka, the wind intensities were above their long-term mean and corresponded with increasing atmospheric CO2. Conversely, from about 11.2 to 7.2 ka, the wind intensities were below their long-term mean and corresponded with decreasing atmospheric CO2. These observations are consistent with model inferences of enhanced SHW contributing to the long-term outgassing of CO2 from the Southern Ocean.

  • AM01 borehole drilled January 2002. Samples collected during drilling and scientific sampling phases of work. AWS continuing to operate.

  • The sedimentological, chemical and isotopic characteristics of sediment cores from three slightly saline to hypersaline lakes (Highway, Ace and Organic Lakes) and two marine inlets (Ellis Fjord and Taynaya Bay) in the Vestfold Hills, Antarctica have been examined. Sections of the cores deposited in marine environments are characterised by uniform, regularly laminated, fine grained, organic-rich sediments, with uniform organic delta 13C values (-18.0 to 19.4 ppt vs. PDB) and sulfur contents. In contrast, sediments deposited in lacustrine environments are extremely heterogeneous, varying from finely laminated mat-like sequences to poorly sorted clastic-rich sediments. Authigenic monohydrocalcite and aragonite occur in some lake sediments. The delta 13C values of organic matter in the lacustrine sediments exhibit an extremely wide range (-10.5 to -25.3 ppt) that can be related to variations in physico-chemical conditions in the lake waters. Strongly negative organic-delta 13C values coupledwith high sulfur contents are indicative of an anoxic zone in the overlying lake waters, whereas less negative organic-delta 13C values coupled with low sulfur contents are indicative of well-mixed oxic conditions. Particularly high organic-delta 13C values result during high levels of microbial activity in the lakes, due to high rates of photosynthetic CO2 fixation. The large shifts in organic-delta 13C are not necessarily accompanied by any change in macroscopic sedimentological characteristics, illustrating the utility if isotopic investigations in these environments. The delta 13C composition of authigenic carbonate in hypersaline Organic Lake sediments provides a record of changes in palaeoproductivity, while the delta 18O of the carbonate provides information on rates of meltwater input and evaporation in the lake. 14C-dating suggests that Highway Lake was isolated from the sea by isostatic uplift at least 4600 years before present (BP) whereas Organic Lake was isolated at approximately 2700 years BP. Apparent emergence rates calculated from the 14C ages range from 1.0 to 2.1 mm per year. The 'reservoir effect' in the lacustrine and marine environments is variable, but probably does not exceed ~ 1000 years in any of the lakes examined.

  • Cores from lakes and the shallow marine were taken for investigation of palaeoclimate through proxies such as grain size, TOC, C:N:S and diatoms. The cores have been 14-C dated with some sheel fragments having been analysed using Amino Acid geochronology. The full postglacial record, plus till and pre-glacial sediments, were recovered from two marine cores at 10.3 and 12 m depth in the sediment respectively. These cores are presently (2000) being analysed. Contact the Chief Investgator for queries about these samples or the project, ASAC1071 - 'Palaeoenvironments of the East Antarctic coast between 50E and 120E'. The fields in this dataset are: core number station-employ lake/marine basin latitude longitude water depth (m) date gear recovery (cm) liner (cm) potsdam storage

  • AM01b borehole site Samples collected during drilling and scientific sampling phases of work. AWS continuing to operate (not a new station, but ongoing AM01 station).