Abstract
Geochemical analysis and field relations of linear dolomite bodies
occurring in outcrop in the Mohawk Valley of New York suggest that
they have undergone significant fault-related hydrothermal
alteration. The dolomite occurs in the Lower Ordovician Tribes
Hill Formation, which is regionally an early Ordovician shaley
limestone with patchy dolomitization. The outcrop has an en
echelon fault, fracture, and fold pattern. A 3D ground penetrating
radar 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, though helpful in characterizing the
conditions of dolomitization, does not define its origin
absolutely. This study uses fluid inclusions, stable isotopes,
3D-ground penetrating radar, core analysis, and surficial
observation 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 Trenton - Black River
hydrothermal dolomite reservoirs of the eastern United States. It
may therefore be studied to help petroleum geologists characterize
existing gas plays and prospect future areas of exploration.
Slater, Brian E., 2007. Outcrop Analog for Lower Paleozoic
Hydrothermal Dolomite Reservoirs, Mohawk Valley, NY
Unpublished MSc. thesis, State University of New York at Albany.
104 pp., +x; folded plate in pocket
University at Albany Science Library call number: SCIENCE
Oversize (*) QE 40 Z899 2007 S53
MS thesis pdf
(6 MB);
Plate 1-6 (combined) - Aerial
photo mosaic, fracture map, and photographic profiles of walls
of trenches at Palatine Bridge outcrop
(colour
poster) - 23 MB pdf file
Return to MS Theses completed in the
Geological Sciences Program, University at Albany