Use of carbon accumulation rates to estimate the duration of coal seams and the influence of atmospheric dust deposition on coal composition

Time contained within coal seams is most commonly estimated using a volumetric approach that fails to take into account processes of carbon accumulation and loss during peat formation and coalification. A more appropriate approach for estimating the time contained within a coal seam is to use Holocene long-term carbon accumulation rates, accounting for carbon loss during coalification. Using this approach the thickness of coal corresponding to 10 kyr of carbon accumulation is calculated for coals of all ranks and latitudinal settings. To test the validity of this approach, latitudinal patterns of Holocene dust deposition are used in conjunction with estimated rates of carbon accumulation to calculate the concentration of titanium in coal. The result is a statistically significant correlation that is optimized when latitudinal variation in carbon accumulation rate is considered. Overall, the use of carbon produces far greater accountability of time within coal-bearing stratigraphic sequences and is not influenced by the presence of hiatal surfaces within the coal. Estimated coal seam duration increases considerably, often removing the need to infer substantial intra-seam hiatuses. On the basis of the results, a re-evaluation of coal and coal-bearing stratigraphic sequences is recommended.