Abstract: Integration of Statistical Analysis of Apatite Fission Track (AFTA) Data and Biostratigraphic Information as a New Tool for Stratigraphic Age Assessment, East Maracaibo Basin, Venezuela

Lorente, M.A. - PDVSA; F. Cassani* - Consultant; R. Donelick - Donelick Analytical Inc.

Apatite fission track analysis allows to interpret the paleothermal history of rocks, as well as the stratigraphic age of uplifting events recorded in the section. Currently the measured AFTA age tends to be younger than the stratigraphic age.

Recently the information obtained from AFTA has been expressed in mathematical form and introduced in a statistical software specially developed to handle this type of data (AFTSolve©) which permits to predict the correct parameters for the paleothermal history modeling and compare it with the measured geological data, as well as, determine the thermal history of a particular geological sample with a known statistical level of confidence.

The present work evaluates the use of this statistical modeling program for the assessment of stratigraphic age in Eocene rocks from three wells of the eastern Maracaibo Basin.

The results allow to visualize a direct relation between the biostratigraphically determined age and the age obtained through AFTSolve© in sample results with high statistical level of confidence.

This permits to constrain the real time of the cooling event, to obtain a better definition of the age for the post Eocene uplifting which took place in the area. As a result we have established that the degree of confidence of the modeling becomes lower as we get further from the biostratigraphically determined age.

Based on these findings it was also possible to apply the present methodology to date sections otherwise barren or very poor in fossils in one of the wells.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil