NAGY, ZSOLT R., University of Missouri-Rolla, Dept. of Geology Geophysics, Rolla, MO

ABSTRACT: Carbonate Sedimentation and Diagenesis in an Extensional-Compressional Setting: Lower Carboniferous of the Irish Midlands

The proposed research will focus on lithofacies and diagenesis of the Supra-Waulsortian carbonate strata in the South Irish Midlands and Dublin Basin region. These rocks were deposited during post Hercynian extension and prior to Variscan compression in the region.

Detailed logging and sampling of core and outcrop sections will be conducted in order to determine precise stratigraphic and facies relationships. Precise biostratigraphic dating of units will be used to correlate between outcrops with boreholes. Standard thin section and cathodoluminescence (CL) petrology will be used to determine microfacies and diagenetic relationships. Carbon, oxygen and strontium isotope geochemistry, and fluid inclusion microthermometry will further constrain diagenetic history.

This work will lead to an understanding of the depositional setting of the Supra-Waulsortian carbonate rocks and the resulting complex stratigraphic relationships within the numerous sub-basins that exist in the area. Petrologic studies will be used to support interpretation of depositional settings and for understanding diagenetic evolution of these rocks. Emphasis will be placed on late diagenetic processes, particularly with regard to fluid flow and hydrocarbon generation and migration. For instance a search will be conducted for petroleum bearing fluid inclusions to establish the timing of hydrocarbon migration relative to CL growth zonation in the cements.

The proposed study will result in a better understanding of complex depositional and diagenetic relationships that exist in similar extensional-compressional tectonic settings.

AAPG Search and Discovery Article #90909©2000 AAPG Foundation Grants-in-Aid