| Sandstone samples from twenty-five conventional cores representing the interval from Upper Jurassic to Upper Cretaceous were obtained from seven exploration wells (COST B-2, COST B-3, SHELL 93-1, SHELL 273-1, SHELL 632-1, TEXACO 598-1, and EXXON 684-2) in the Baltimore Canyon Trough. These sandstones were examined using petrography, whole rock geochemistry, and x-ray diffraction analyses. The cores from different wells were integrated to make a single composite stratigraphic column.; Based on modal analyses, the compositions of the sandstones are predominantly subarkosic, with subordinate arkose and sublitharenites. The sandstones have been diagenetically altered.; Examination of available porosity and permeability data shows that the porosity decreases exponentially with depth, and the rate of decrease of porosity is controlled by geothermal gradients and diagenesis within the basin.; The formation waters sampled during drill-stem testing belong to the chloride-calcium type that have remained hydrologically isolated.; Based on petrography, the Upper Jurassic sandstones belonging to Oxfordian, Kimmeridgian, and Tithonian stages were derived from an assemblage of sedimentary and metamorphic provenance, reflect severe to mild source-area uplift, and petrographically fall in the transitional continental to quartzose recycled subfields of Dickinson plots. The Lower Cretaceous sandstones belonging to Berriasian, Valanginian, Hautervian, Berremian, Aptian, and Albian stages were derived from a metamorphic, sedimentary, and minor volcanic provenance, reflect a fluctuating source-area tectonism, and fall within the craton interior/transitional continental to quartzose recycled subfields of Dickinson plots. The Upper Cretaceous sandstones from the Santonian, Campanian, and Maestrichtian were predominantly derived from metamorphic provenance, reflect a mild source-area tectonism, and fall within the craton interior/recycled orogen of Dickinson subfields.; Whole rock geochemistry has been useful for interpreting the source area tectonics for clastic sediments without a volcanic provenance.; Detailed petrography has overcome the effects of diagenesis for interpretation of tectonics using the Dickinson diagrams. However, the low percentage of feldspars and lithic fragments present in the passive margin sandstones of Baltimore Canyon Trough, unlike those from the active tectonic margins, have a limited spread near the "quartz" pole of Dickinson diagrams. |
