MRCSP Phase I Geologic Characterization Report - Midwest ...

APPENDIX A: BASAL SANDSTONES TO TOP OF COPPER RIDGE INTERVAL
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Group, Beekmantown Group, Black River and Trenton limestones,
and the Upper Ordovician clastics of the Cincinnati Group, Reedsville
Shale, and Martinsburg Formation (Figure 5) directly overlie
the injection interval. Additional layers of Middle and Upper Paleozoic
clastics, carbonates, and evaporates would be added on top of
this with increasing depth.
3. BASAL SANDSTONES TO TOP OF COPPER RIDGE INTERVAL
The stratigraphic interval from the top of the basal sandstones to
the top of the Copper Ridge Dolomite (Figure 5) serves largely as
a confining interval for possible injection in the underlying basal
sandstones of the MRCSP study area. In some locations, however,
units within the interval may be possible injection targets, although
even for these units, the remainder of the interval would be considered
a seal.
The Basal Sandstones to the top of the Copper Ridge Interval can
be divided into three informal sub-intervals across the region for
descriptive purposes: 1) a thick clastic and carbonate interval above
the basal sandstones within the Rome trough, including the Tomstown
Dolomite, Rome Formation, Waynesboro Formation, and
the lower part of the Conasauga Group; 2) an interval dominated
by clastics in the west and carbonates in the east above the basal
sandstones outside of the Rome trough, and continuous above the
trough-filling interval, which includes the Eau Claire Formation,
Conasauga Group, Elbrook Formation, and Warrior Formations;
and 3) an upper, carbonate-dominated interval, that is extensive
across the region, including the upper Munising Group, Trempealeau
Formation, Davis Formation, Potosi Dolomite, Copper Ridge
Dolomite, Gatesburg Formation, and Conococheague Group (Figure
5). Stratigraphic relationships and thicknesses for these units in
the eastern half of the MRCSP study area are based on a series of
published regional cross sections (Ryder, 1991, 1992a; Ryder and
others, 1992, 1996, 1997).
Tomstown/Rome/Waynesboro/Lower Conasauga Formations—Units
in this sub-interval are mostly confined to the Rome trough of
eastern Kentucky, West Virginia, and Pennsylvania, and the eastern
proto-Appalachian basin as far east as Maryland (Figures 5 and 6).
The Shady or Tomstown Dolomite (250 to 500 feet thick) overlies
the basal sandstone in the Rome trough and areas south and east
of the Rome trough. The Shady/Tomstown is overlain by mixed
clastics and carbonates of the Rome Formation in the Rome trough.
Across the northern bounding faults of the Rome trough in eastern
Kentucky, the Rome Formation may thicken from less than 300 feet
to more than 6,000 feet, depending on usage (definitions of the top
of the Rome have varied). In West Virginia, dramatic increases in
thickness also occur across the southern or eastern fault boundary,
although this is based on a limited number of wells deep enough
to confirm the exact offset across the southern bounding faults
into southern West Virginia. Eastward into northern West Virginia,
Maryland, and Pennsylvania, the Shady/Tomstown Dolomite is
overlain by shale and siltstone of the Waynesboro Formation (Figure
5). The Waynesboro (400 to 500 feet thick) is equivalent to that
part of the Rome Formation that extends south and east of the Rome
trough. The Rome is overlain by the Conasauga Group (Figure 5).
Like the underlying Rome Formation, the lower part of the Conasauga
shows dramatic thickening into the Rome trough (from less
than 200 feet north of the Rome trough, to more than 5,000 feet
within the trough). In eastern Kentucky and West Virginia, six formations
are defined within the Conasauga, from oldest to youngest:
1) the Pumpkin Valley Shale (0 to 300 feet thick); 2) the Rutledge
Limestone (0 to 1,200 feet thick); 3) the Rogersville Shale (0 to 700
feet thick); 4) the Maryville Limestone (0 to 2,400 feet thick); 5) the
Nolichucky Shale (0 to 500 feet thick); and 6) the Maynardsville
Limestone (0 to 200 feet thick). The three lower formations are confined
to the Rome trough, as is the lower part of the Maryville. The
three upper units extend beyond the trough, but become thinner, and
pinch out or merge with lateral units.
Eau Claire/Conasauga/Elbrook/Warrior Formations—In the
proto-Illinois/Michigan basin of Indiana and Michigan (Figure 6),
the basal sandstone is overlain by the Munising Group (Figure 5).
The lower part of the Munising is called the Eau Claire Formation
(100 to 1,000 feet thick), which extends from Indiana and Michigan
into western and central Ohio and northern Kentucky (Shaver and
others, 1986; Rupp, 1991; Catacosinos and others, 2001). Eastward
from central Ohio, the Eau Claire Formation thins and merges laterally
into the Conasauga Group. That part of the Conasauga Group
above the basal sand in southeastern Ohio and northeastern Kentucky
represents only the upper part of the Conasauga preserved to
the southeast in the Rome trough (Figure 5). In the trough, the upper
third of the Maryville Limestone, the Nolichucky Shale, and the
Maynardsville Limestone are equivalent to the Eau Claire. Farther
east, the upper two thirds of the Maryville Limestone interfingers
with the Elbrook Formation/Dolomite, and the Nolichucky and
Maynardsville pinch out or are truncated beneath the lower sandy
interval of the overlying Copper Ridge Dolomite. The lower third
of the Elbrook (also called the Honaker Dolomite) is equivalent to
the lower part of the Conasauga Group in the Rome trough, as well
as an unnamed limestone in the upper Rome Formation. North and
east into Pennsylvania, the Elbrook is estimated to be more than
3,000 feet thick (Kauffman, 1999). In central and western Pennsylvania,
the lower part of the Elbrook is equivalent to the Pleasant Hill
Limestone/Formation (400 to 500 feet thick), and the upper part of
the Elbrook is equivalent to the Warrior Formation (400 to 1,200
feet thick). In some parts of western Pennsylvania, the Warrior Formation
rests directly on the Potsdam Sandstone, which is the basal
sandstone in this area, but younger than the basal sandstone in the
Rome trough (Figure 5).
Upper Munising/Trempealeau/Potosi/Davis/Copper Ridge/Gatesburg/Conococheague
Formations—In Michigan, this sub-interval
includes the upper part of the Munising Group and the overlying
Trempealeau Formation (Milstein, 1983) (Figure 5). The Munising
consists of the Galesville Sandstone (less than 100 to 600 feet thick)
and Franconia Formation (100 to 500 feet thick). The Galesville
and Franconia thicken toward the Chicago area in northern Illinois
(Becker and others, 1978). In Indiana, the Ironton Sandstone occurs
between the Galesville and Franconia within the upper Munising
Group, and these units are restricted to the northwestern part of
the state (Becker and others, 1978). Where the Munising Group
thins southward and eastward in Indiana, the upper Munising is
equivalent to the Davis Formation (Figure 5). The Davis thins gradationally
into the Potosi Dolomite in southern Indiana (Shaver and
others, 1986). The overlying Trempealeau Formation in Michigan
(less than 100 to 900 feet thick) is also equivalent to the Potosi Dolomite
(20 to 2,000 feet thick). Eastward, the Potosi is equivalent to
the Copper Ridge Dolomite (700 to 1,200 feet thick) in Ohio, Kentucky,
and western West Virginia, and the Conococheague Group/
Limestone (2,500 feet thick) in eastern West Virginia, Pennsylvania,
and Maryland. The Gatesburg Formation (1,000 to 1,350 feet thick)