The records of dust accumulation rates from version 2 (2002) and 1 (2001) of the DIRTMAP data base, including dust information from ice cores, marine sediments, marine sediment traps, and loess sediments. Mass accumulation rates are estimated in g/m2/yr, and a LGM/Holocene ratio are provided where possible. All data were compiled from the literature.
In addition to containing more sites than ... version 1.0 (including data from some terrestrial deposits), DIRTMAP version 2.0 also contains information on site age models (e.g. layer counting, radiocarbon, oxygen isotope stratigraphy), the time interval over which accumulation rates were averaged, the type of information used to calculate an aeolian accumulation rate (e.g. isolation of terrigenous components, Al concentration measurements, number or mass concentrations). This data set also contains (in a separate table) estimates of non-carbonate accumulation rates in marine sediments [Catubig et al., 1998], which can in some cases be used as a first order estimate of dust accumulation rates (e.g., in regions with low opal and organic carbon rates).
In version 2.0, all marine sediment data have also been screened to indicate where contamination problems (e.g. regions with ice-rafted detritus, fluvial input, lateral sediment redistribution). Potentially contaminated sites are still included in the data set but are flagged. It is important to make sure that all flagged sites are removed from the data set before data are compared directly with simulated dust accumulation rates.
Data are included in Version 2 as a series of text tables: Table 1. Ice Core Data Table 2. Marine Sediment Data - Terrigenous Fraction Measured Table 3. Marine Sediment Trap Data Table 4. Marine Sediments - Non-Carbonate Accumulation Rates ONLY Table 5. Terrestrial Sediment Data Table 6. All Data Combined, (excluding sites that have been flagged) Table 7. Flagged Data
Version 1 includes: Table1.doc, DIRTMAP_Table2.doc (Microsoft Word Format). Table1 ? Dust deposition fluxes retrieved from ice cores Table 2a ? Eolian Fluxes to Marine Sediments Table2b ? Eolian Fluxes to Marine Sediment Traps
Kohfeld, K.E., and S.P. Harrison, DIRTMAP: The geologic record of dust, Earth Science Reviews, 54 (1-3), 81-114, 2001.
Mahowald, N., Kohfeld, K. E., Hansson, M., Balkanski, Y., Harrison, S. P., Prentice, I. C., Schulz, M., and Rodhe, H., 1999. Dust sources and deposition during the Last Glacial Maximum and current climate: A comparison of model results with palaeodata from ice cores and marine sediments. Journal of Geophysical Research 104, 15, 895-15, 916.
Tegen, I., S.P. Harrison, K. E. Kohfeld, I.C. Prentice, M. Coe and M. Heimann The impact of vegetation and preferential source areas on global dust aerosol: Results from a model study. Journal of Geophysical Research.(in press).