1. Australian Antarctic Data Centre
2. Discover and Manage Data
3. Records
4. DSS_age_scale

Description

Records of methane, and oxygen isotopes (ice and air) for Law Dome DSS (Dome Summit South) core through the last deglaciation (9000-19000 before present).

Data are obtained from the entire DSS core, collected between late 1987 and early 1993.

Data comprise air composition measurements (d18Oair (per mille) and methane composition (ppbv)) and water isotope data (per mille) from the Law Dome core with age scale matched to the GRIP (Greenland) ice core. Default age scale (yr BP, 1950) gives best age scale - LDmin age scale gives a minimum age limiting case that is not the preferred dating.

Supporting information is provided in a pdf document available both in the dataset for download, and the online Science site.

This work was completed as part of ASAC project 757.

The work is also related to the Greenland Ice Core Project (GRIP), and the Greenland Ice Sheet Project Two (GISP2).

The last deglaciation was marked by large, hemispheric, millennial-scale climate variations: the Bolling-Allerod and Younger Dryas periods in the north, and the Antarctic Cold Reversal in the south. A chronology from the high-accumulation Law Dome East Antarctic ice core constrains the relative timing of these two events and provides strong evidence that the cooling at the start of the Antarctic Cold Reversal did not follow the abrupt warming during the northern Bolling transition around 14,500 years ago. This result suggests that southern changes are not a direct response to abrupt changes in North Atlantic thermohaline circulation, as is assumed in the conventional picture of a hemispheric temperature seesaw.

Public Summary from project 757:
Prediction of future climate change requires knowledge of past changes. Polar snow forms an archive of environmental conditions that is accessible by drilling and analysing ice cores. This project uses ice core data to reconstruct and study records, including past temperature and atmospheric composition, to improve understanding of the climate system.

The fields in this dataset are:

(Note: Ages are all BP (1950); the two scenarios only give identical gas-ages at tie-points.)

Sample Mid Depth (metres)
Sample Length (metres)
Delta 18O air (ppt)
Sample Mid Gas Age (Default)
Delta Age (Default) (years)
Sample Mid Gas Age (LDmin)
Delta Age (LDmin) (years)
CH4 (ppbv)
Depth (metres)
Age (Default)
Age (LDmin)
Delta 18 O (ppt)

Quality

Data have been published, and are considered good. Stop date provided in temporal coverage is the date of publication.

Access

The dataset is available from the url's given below. The pdf document is available both on an external website, and as part of the download with the data itself.

Temporal Coverages

• Start date: 1987-12-01 - Stop date: 2002-08-02

Spatial Coverages

Science Keywords

• EARTH SCIENCE > CRYOSPHERE > GLACIERS/ICE SHEETS > ICE SHEETS
• EARTH SCIENCE > CRYOSPHERE > SNOW/ICE
• EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS > ICE CORE AIR BUBBLES
• EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS > ISOTOPES
• EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS > METHANE
• EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC CHEMISTRY > CARBON AND HYDROCARBON COMPOUNDS > METHANE
• EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC CHEMISTRY > OXYGEN COMPOUNDS > MOLECULAR OXYGEN

Use Constraints

This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/).

Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=DSS_age_scale when using these data.