MRCSP Phase I Geologic Characterization Report - Midwest ...

96 CHARACTERIZATION OF GEOLOGIC SEQUESTRATION OPPORTUNITIES IN THE MRCSP REGION
fossiliferous, silt- and sand-sized grainstones, calcareous shales, and
silty argillites; dark gray to black, medium bedded, cherty, silt-size
grainstones with silty argillites and platy shales; and 4) terrigenous
black shales interbedded with thin-bedded mudstones and calcarenites
(Head, 1969). In south-central Pennsylvania, western Maryland,
and northeastern West Virginia, the upper calcareous facies of the
Helderberg (Licking Creek Limestone grades upward into the Oriskany
Sandstone. Many drillers have difficulty separating the two,
and the formational contact typically is placed at the base of the
lowest arenaceous sequence.
The Huntersville Chert is characterized as “variously . . . dark,
noncacareous shale, carcareous silty shale, calcareous siltstone, argillaceous
and silty or sandy limestone, and a subordinate amount of
glauconitic or conglomeratic quartz sandstone” (Basan and others,
1980, p. 42). The sandy facies contains well-rounded quartz grains
where the Huntersville lies directly on the Oriskany Sandstone. Thin
argillaceous sandstone beds, phosphatic nodules, and glauconite occur
in the basal Huntersville as well, indicating the presence of an
erosional surface on the top of the Oriskany.
The Onondaga Limestone in northern Ohio consists of lightcolored,
micritic to coarse-grained, sparry, fossiliferous limestone
with fairly abundant chert (Janssens, 1997). The color changes to
medium-gray to black to the east. The Onondaga tends to be very
argillaceous in the upper portion in places where the limestone
grades upward into the organic-rich shales of the Marcellus or
“lower” Olentangy formations (Van Tyne, 1996a). In central and
western Ohio, the Columbus Limestone is about 215 feet thick
and composed of gray to bluish-gray, partly crystalline, and cherty
limestone. In the Michigan basin, the Lucas Formation is a siliceous
(cherty) dolostone about 35 feet thick, which makes this formation
especially distinguishable from the Onondaga and Columbus
limestones (Janssens, 1997). The Jeffersonville Limestone of Indiana
is brown to gray, dense to crystalline, thick-bedded, dolomitic
limestone typically less than 50 feet thick (Patton and Dawson, in
Murray, 1955).
DISCUSSION OF DEPTH AND THICKNESS RANGES
Figure A8-2.—Detailed stratigraphic column and geophysical log curves of
the Niagaran thru Onondaga interval from a well in Columbiana County,
eastern Ohio (from Mesolella, 1978).
The Niagaran/Lockport thru Onondaga Interval is relatively shallow
over the arches of the region, but attains greater depths in the
basins (Figure A8-3). The top of the interval is mostly below 2,000
feet in the Michigan basin, whereas the base is below 8,000 feet
in the deepest parts of that basin. In Indiana and western Ohio, the
interval is quite shallow, straddling the Cincinnati arch and cropping
out along either side of the arch. In the Appalachian basin, the top of
the interval ranges from -1,000 feet along the Lake Erie shoreline,
to -7,500 feet in south central Pennsylvania. The base ranges from
-2,000 feet along Lake Erie to more than -10,000 feet in Somerset
County, Pennsylvania (Figure A8-3). In eastern Kentucky several
fields produce from this interval at depths of -2,000 to -2,500 feet,
but most reservoirs, including the Big Sinking field, are shallower,
with depths from -500 to -1,500 feet (Nuttall and others, 2003).
The interval thickness ranges from 250 feet in eastern Kentucky
and northern Indiana to more than 6,000 feet in the central part of
the Michigan basin (Figure A8-4). Within the Appalachian basin,
thickness increases northeastward from about 250 feet in eastern
Kentucky to approximately 3,000 feet in central Pennsylvania and
western Maryland. These dramatic increases in thickness result
mainly from the large accumulations of carbonates and evaporites
in the Salina Group.
DEPOSITIONAL ENVIRONMENTS/
PALEOGEOGRAPHY/TECTONISM
Most of the environments represented in this heterolithic interval
are normal or restricted marine facies. Intervals of evaporite deposition
represent even greater restriction in local areas. The sandstones
represent shallow marine or coastal settings (Smosna and Patchen,
1978). The carbonate rocks, in many cases, are influenced by the
basin-fringing reef belts, with shallow tidal to supratidal deposits
forming behind the reef systems, and deeper subtidal accumulations
forming in the basinward settings. In some settings within the
deeper portions of the basins, the rocks are very fine grained and
rich in shale and clay.