02172nas a2200169 4500008004100000245010100041210006900142300001400211490000700225520160700232653001401839653001701853653002801870100001901898700001801917856006701935 2012 eng d00aOutcrop Analog for Trenton-Black River Hydrothermal Dolomite Reservoirs, Mohawk Valley, New York0 aOutcrop Analog for TrentonBlack River Hydrothermal Dolomite Rese a1369-13880 v963 a
Geochemical analysis and field relations of linear dolomite bodies occurring in outcrop in the Mohawk Valley of New York suggest that the area has undergone a significant fault-related hydrothermal alteration. The dolomite occurs in the Lower Ordovician Tribes Hill Formation, which is regionally a Lower Ordovician shaley limestone with patchy dolomitization. The outcrop has an en echelon fault, fracture, and fold pattern. A three-dimensional (3-D) ground-penetrating radar (GPR) survey of the quarry floor has helped to map out faults, fractures, anticlines, synclines, and the extent of dolomitization. Most of the dolomitization occurs in fault-bounded synclines or sags flanked by anticlines. The dolomite structures are highly localized, occurring around faults, and are absent away from the faults and fractures. Trenches cut across the outcrop help relate offset along faults to the overall geometry of the dolomitized bodies. Geochemical analysis, although helpful in characterizing the conditions of dolomitization, does not define its origin absolutely. This study uses fluid inclusions, stable isotopes, 3-D GPR, core analysis, and surficial observations, which all show a link between faulting, dolomitization, and other hydrothermal alteration. Although the outcrop is much too small and shallow to act as a producing gas field, it serves as a scaled analog for the Trenton–Black River hydrothermal dolomite reservoirs of eastern United States. It may therefore be studied to help petroleum geologists characterize existing gas plays and prospect future areas of exploration.
10aDolomites10aGeochemistry10aHydrothermal alteration1 aSlater, B., E.1 aSmith, L., B. uhttp://aapgbull.geoscienceworld.org/content/96/7/1369.abstract