Print this pageCalculating Volumes and Rates of Carbonate Accumulation in the Jurassic of Eastern France: Impact on Stratigraphic Prediction and Modeling
DROMART, GILLES, PASCAL ALLEMAND, JEAN-PIERRE GARCIA, FABRICE GAUMET, and BRUNO ROUSSELLE
Volumes and rates of pure carbonate accumulation are calculated on the basis of 3-D depositional geometries restored by correlating wells and outcrops for two distinct scale lengths: 40,000 km{2} and 10,000 km{2}, with a time-resolution varying from 0,5 to 2,5 Ma. The selection of the surfaces is made on the basis of possible biostratigraphic-geochronologic- assignments and unmistakable identification all over each study area. For each site, a theorical accumulation of pure carbonate is calculated by multiplying the total thickness and the relative carbonate contents. The volumes limited by two successive time-surfaces are then computed by integrating distances between the sites. The results are normalized so as to express rates in m/Ma. Those rates are reflect net production rates for a given time interval over a given pace including shallow to offshore depositional environments. Additionally, carbonate accumulation rates are calculated for each site, and isorate maps are drafted and superimposed with maps of depositional environments.
The overall processing is meant to address the following points of primary interest in promoting stratigraphic prediction and modeling: (1) What is the limitation of the carbonate production potential that implies volumetric partitioning of sediments between shallow and offshore environments? (2) What are real carbonate production rates of ancient systems when restricting total volumes of carbonates to productive areas only? (3) What is the respective influence of the production variable against the diffusivity variable on carbonate depositional profiles (ramps vs platforms)?