SAMPLING AND PHYSICAL EFFECTS ON SPACE/TIME DISTRIBUTION OF ANTARCTIC AGE DATA FROM A GLACIO-GEOLOGICAL DATABASE

A digital database of absolute dates relevant to ice-sheet geometry has been established at BAS. This will be used to constrain models of the Holocene retreat of the Antarctic ice sheet. The amount of Antarctic absolute age data spanning the last glacial cycle has grown considerably, especially in the last decade. The present database (AGGD) forms the first ever that links geological field-data on a continent wide scale to inverse ice sheet modelling. Data from 124 different research papers are reviewed and divided over thirteen different geographical areas. The requirement for absolute age input in the AGGD is that each date is tied to a specific physical environment. The reconstruction of physical (or sedimentary) environments in this study is highly promoted by the sophisticated nature of recent studies in the field. Limitations of dating and calibration methods, quantitative errors, and ‘reservoir’ correction are reviewed and implemented within the AGGD.

Frequency distributions of absolute ages (time slices) show a number of similarities and differences between West- and East-Antarctica. We discuss how these can be attributed to sampling, physical and historical effects.