Tracking the key parameters stimulating organic carbon productivity, accumulation rate and preservation based on foraminiferal proxies in the subsurface Miocene sediments in north Sinai, Egypt

Abstract

Productivity, redox conditions and sedimentation rate constrain the enrichments of organic matters and under suitable conditions they can trigger larger enrichments. These parameters are tracked in the subsurface Miocene sediments in four wells on east to west transect across north Sinai. These wells are Abu Roda-1, Misfaq-1, Teffah-1 and Einab-1. The Miocene sections cover the Aquitanian, Burdigalian, Langhian, Serravalian and Tortonian. The tracking is based on the proxies of planktonic and benthic foraminifera that offer many solutions in the application of the equations used to calculate these parameters. The first of these parameters is the sedimentation rate which is calculated for different time segments based on the planktonic foraminifera bioevents. The sedimentation rates are correlated throughout the basin. The second parameter is the water depth that is obtained from conversion of the scores of component 1 resulted during the routine statistical analysis of the benthic foraminifera by cluster and principal component analyses. These analyses are used also in assessment of redox condition and eutrophication. The sedimentation rates and water paleobathymetry alongside the measured Corg are used to calculate the paleoproductivity and to determine four stratigraphic sequences (Seq1, Seq2, Seq3 and Seq4). The tracking of these parameters reveal higher productivity levels in the Seq1 (Aquitanian and Burdigalian) accompanied with dysoxic and mesotrophic conditions, however the lower sedimentation rates are not optimum to stimulate enough burial efficiency that reduced values of Corg. In the younger sequences (Seq2-4), the higher sedimentation rates increase the burial efficiency and values of Corg despite the lower paleoproductivity and oxic oligotrphic conditions.