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Figure Captions
Figure
1. Geologic map of south-central Oklahoma (modified from Miser, 1954),
with location of paleo- cross - sections (Figures
3,
4,
5,
6,
7,
8) (east) (with link from line of section only to Figure 3) and
location of cross -section of Ardmore Basin (Figure
9) (west).
.
Figure 2a. Correlation chart for Ardmore
Basin.
Figure
2b. Estimated stratigraphic thickness, south-central Oklahoma; thickness
of Pennsylvanian Hoxbar to granite of 31,845 feet was used in this
study.
Figure 3. Generalized, diagrammatic
paleo- cross -section, Criner Hills / Ardmore Basin / Arbuckle Mountains /
Mill Creek Syncline / Pauls Valley Uplift, Middle Ordovician; location
shown in Figure 1.
Click here
for sequence of Figures 3, 4, 5, 6, 7, 8.
Figure 4. Generalized, diagrammatic
paleo- cross -section, Criner Hills / Ardmore Basin / Arbuckle Mountains /
Mill Creek Syncline / Pauls Valley Uplift, Late Ordovician-Devonian;
location shown in
Figure 1.
Click here
for sequence of Figures 3, 4, 5, 6, 7, 8.
Figure 5. Generalized, diagrammatic
paleo- cross -section, Criner Hills / Ardmore Basin / Arbuckle Mountains /
Mill Creek Syncline / Pauls Valley Uplift, Early Pennsylvanian; location
shown in Figure 1.
Click here
for sequence of Figures 3, 4, 5, 6, 7, 8.
Figure 6. Generalized, diagrammatic
paleo- cross -section, Criner Hills / Ardmore Basin / Arbuckle Mountains /
Mill Creek Syncline / Pauls Valley Uplift, Early Pennsylvanian, after
Wichita Orogeny; location shown in Figure 1.
Click here
for sequence of Figures 3, 4, 5, 6, 7, 8.
Figure 7. Generalized, diagrammatic
paleo- cross -section, Criner Hills / Ardmore Basin / Arbuckle Mountains /
Mill Creek Syncline / Pauls Valley Uplift, Late Pennsylvanian, after the
deposition of the Hoxbar; Deese and Dornick Hills; location shown in
Figure 1.
Click here
for sequence of Figures 3, 4, 5, 6, 7, 8.
Figure 8. Generalized, diagrammatic
paleo- cross -section, Criner Hills / Ardmore Basin / Arbuckle Mountains /
Mill Creek Syncline / Pauls Valley Uplift, Late Pennsylvanian, following
the Arbuckle Orogeny; location shown in Figure
1.
Click here
for sequence of Figures 3, 4, 5, 6, 7, 8.
Figure 9. Structural cross -section, Ardmore Basin. Location shown in
Figure 1.
Figure 10. Cross -section, Southeast Eola Field, showing overturned beds,
major fault, and a thick Springer section in the center of syncline;
location in Figure
1.
Figure 11. Ardmore area map, with Criner Hills, showing locations of
cross - sections through Southwest Ardmore Field (Figure
12) and
Cottonwood Creek Field (Figure 13).
Figure 12. Cross -section, Southwest Ardmore Field, southeast Criner
Hills, showing tightly folded beds cut by high-angle reverse faults.
Location in Figure 11.
Figure 13. Cross -section, Cottonwood Creek Oil Field, with major
unconformity across productive fold in downthrown block of reverse fault. Location in
Figure 11.
Figure 14. Geologic map of part of the Arbuckle Mountains (after Ham,
McKinley, et al., 1954), with locations of areas near the town of Davis
(Figures 15, 16,
17, 18, 19,
& 20).
Figure 15. Southeast Hoover Oil Field, in upthrown block of major
reverse fault, showing disharmonic folds with local thrust fault;
location (Area 3) in Figure 14.
Figure 16. Part of electric log of Mapco
#7 Howell (NE NW SW NE sec. 14, T1S, R1E) in Southwest Davis Oil Field,
showing repetition of Ordovician Basal Oil Creek sand; location within
Area 4 in Figure 14.
Figure 17. Cross -section, Southwest
Davis Oil Field, showing anticlinal feature in downthrown block of the
reverse (thrust) fault (to the northeast), recognized by repetition of
the Basal Oil Creek sand in key wells; location (Area 4) in Figure
14.
Figure
18. Cross -section, utilizing surface data, north flank of the Arbuckle
Mountains. This cross -section shows Washita Valley fault and the
vertical to overturned beds in the downthrown block along road cuts;
location (Area 5) in Figure 14.
Figure 19. Cross -section, Southwest Sandy Creek
Oil Field, showing four normal faults; along some of them are fault
traps and seals. Location (part of Area 6) in
Figure 14.
Figure 20. Cross -section, Southwest Sandy Creek Field - Pauls Valley
Uplift, with the former lying southwest of faulted, tightly folded,
overturned syncline, which in turn is southwest of anticlinal feature in
the upthrown block of reverse fault bounding the uplift, all below a
major unconformity. Location (part of Area 6) in Figure
14.
Figure 21. Location map of cross -section of Pauls Valley Uplift (Figure
22). The location of a cross -section is west of Interstate 35 between
Elmore City and Wynnewood.
Figure
22. Cross -section of Pauls Valley Uplift (location in Figure
21). Beds
below and above Wichitan unconformity dip southwest- and west, and an
unconformity separates Pennsylvanian Deese and Hoxbar groups.
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to top.
The area of study (Figure
1), some 4,750
square miles (T6S-T5N, R6W-R6E) in south-central Oklahoma, includes
the Ardmore Basin as the central element. The surface features from
south to north include the Criner Hills, Caddo Anticline, Arbuckle
Mountains, Mill Creek Syncline, and Pauls Valley Uplift. In traditional
terms, the Ardmore Basin lies between the Criner Hills and the Arbuckle
Mountains, but it was more extensive before the Arbuckle Orogeny
(Figures 2a and 2b; Figures
3, 4, 5,
6, 7, 8).
In Figure 1, locations are identified of
wells (1 through 7) that were used in determining a representative
stratigraphic section and thicknesses for the units. These were utilized
in preparing a series of cross - sections (from T5S,R1E to T2N,R5E--Figure
1) to illustrate depositional history and tectonism of the area.
Stratigraphy
and Tectonic Events
The samples from the seven wells located
on Figure 1 were identified according to stratigraphic unit and
thickness by Bronston W. James and the author.. In addition, Robert O.
Fay, Oklahoma Geological Survey, identified and measured the thickness
of each unit in the Arbuckle Mountains along I-35 highway. The results
of these two studies (Figure 2b) show that there is a total
stratigraphic section, Hoxbar to basement, of 31,845 feet.
In this part of Oklahoma, basement rock is
the Precambrian Tishomingo Granite, dated by radiometric methods as 1374
Ma. It crops out in T1-2S, R5-6E. This granite or equivalents are
thought to underlie the entire study area (Figures
3,
4,
5,
6,
7,
8). Hamilton Brothers #1 Turner Falls well (see
Figure 14) drilled through 15,840 feet of Cambrian stratiform
igneous rocks (Carlton Rhyolite) before it penetrated carbonates of the
Ordovician Arbuckle Group.
The Upper Cambrian Reagan Sandstone
overlies the rhyolite, and it in turn is overlain by the Honey Creek
Limestone. The overlying Arbuckle Group, the Arbuckle is estimated to be
9,000 feet thick near the Criner Hills, some 6,700 feet thick in the
Arbuckle Mountains, and about 5,000 feet thick in the Pauls Valley
Uplift. Upper Ordovician to Devonian strata, which are an additional
3,900 feet in thickness, consist of the Simpson Group, Viola Limestone,
Sylvan Shale, and Hunton carbonates.
The first uplift of these rocks occurred
during the Acadian Orogeny (Figure 2b), near the close of the Devonian.
Pure #1 Resources Unit well (No. 5, Figure 1) drilled from the Woodford
(Misener sand) to eroded Viola at 18,675 feet. The subsequent period of
deposition was from the Devonian to Early Pennsylvanian (Figure
5). An
additional 6,250 feet of sediments was deposited, with a total thickness
at that time of 17,760 feet. The basin extended from the Criner Hills to
the north side of the Pauls Valley Uplift. Each of the rock units Woodford, Sycamore, Caney, Springer, and Goddard, from oldest to
youngest, has its own distinguishing characteristics. The Springer
Formation, with its massive sands, has produced much oil and together
with the Goddard has been responsible to a significant extent for
ductile deformation (e.g., disharmonic folding), a common feature of the
area.
The Wichita Orogeny, which occurred
after deposition of the Springer during Early Pennsylvanian, resulted in
formation of the Criner Hills and the Pauls Valley Uplift (Figure 6).
During Middle and Late Pennsylvanian (Figure 7), an additional 14,085
feet of sediments were deposited in this basin, with the total thickness
of sedimentary rocks from Hoxbar to Granite being 31,845 feet. This
youngest suite of sediments, oldest to youngest, are the Dornick Hills (Atokan
and the Morrowan), Deese (Desmoinesian), and the Hoxbar formations.
The Caddo Anticline and the Arbuckle
Mountains formed during the Arbuckle Orogeny, following deposition of
the Hoxbar Formation (Figure 8). The Hoxbar, Deese, and Dornick Hills
sediments in the area between the Criner Hills to the south and the
Pauls Valley Uplift to the north were complexly folded and faulted
during the this orogeny.
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Representative Cross - sections Demonstrating Structural Complexity
A cross -section of the Ardmore Basin (Figure
9) extends from the South Palacine area, T2S, R6W, through Eola,
T1N, R2W, to the Golden Trend, T2N, R2W (on the plunge of the Pauls
Valley Uplift). The section shows major faulting, overturned beds (more
commonly toward the northeast), and a thick sedimentary section. The
cross -section of Eola Field (Figure 10) shows the Arbuckle formations,
Reagan sandstone, and rhyolite (basement for sedimentary rocks) thrust
over a gray shale (Deese) and Arbuckle units over synorogenic
conglomerate, with the Deese unconformably overlying overturned Springer
to Arbuckle beds. In effect, the major fault, dipping to the southwest,
is under a buried part of the Arbuckle Mountains.
Complex faulting and faulting in the
Criner Hills area (Figure 11) are shown by
the cross -section in
Figure 12. It extends across Southwest Ardmore Field near the
southeast end of the Criner Hills.
Figure 13 is across Cottonwood
Creek Oil Field, 10 miles west of Ardmore. This field produces from the
Brown zone, the basal part of the West Spring Creek Formation of the
Arbuckle Group. In the Continental #1 Smith (Figure
13), the Deese rests unconformably on the Viola, below which a
normal section is present through the Brown zone. Older units are
present above a fault, which in turn is above a repeated West Spring
Creek Formation, including the Brown zone. Updip to the northeast in the
downthrown fault block, the Brown zone is above an oil-water contact in
a trap formed by beds farther to the northeast dipping in that
direction. The section of Hoxbar, Deese, and Dornick Hills above the
steeply dipping Pre-Pennsylvanian beds show relatively gentle dips, with
onlap of the lower units to the southwest.
Southeast Hoover Field (Area 3, Figure
14) also produces oil from the Brown zone well below gently dipping
Permian rocks in a faulted, disharmonic anticline (Figure
15). At the
west edge of the cross -section, the Oil Creek sand (Ordovician Simpson)
is dipping steeply to the west. Just to the east, the Oil Creek is also
present in the overturned limb of a syncline coupled with a
thrust-faulted anticline. A well that encountered the fault, which dies
out into the Oil Creek, contains approximately 1,600 feet of repeated
section. The Basal Oil Creek sand, the Joins (Simpson), and the Arbuckle
are not affected by this fault or the complex folding. The major reverse
fault to the east shows 7,000 feet of vertical displacement of the
Viola.
Southwest Davis (Area 4, Figure
14), is
an oil field that produces from the Basal Oil Creek sand. On outcrop of
this sand just a few miles away, the sand is mined for its high quartz
content. A portion of the electric log from Mapco #2 Howell is shown in
Figure 16. At 3,700 feet, the sand is 60 feet thick, about half of its
normal thickness. While following the instructions to drill 100 feet
below the base of the sand, sample examination indicated that the Joins
member of the Simpson was not being drilled--rather a thrust
fault had been drilled and the Oil Creek section was repeated. Upon
additional drilling, the Basal Oil Creek sand was drilled a second time
at 4,080 feet. At this position, the sand was also saturated with oil,
and the sand has a normal thickness of 140 feet. Further drilling found
the Joins and the Arbuckle in a normal sequence. The electric log
confirmed the sample descriptions that were logged during drilling. In
this well this sand was above the oil-water contact in both fault
blocks. The cross -section in the Southwest Davis Field (Figure 17) shows
abnormal thickness of the Oil Creek formation, probably due in part to
relatively minor faulting. One of the wells shows a repeated the Basal
Oil Creek sand, with the sand in the downthrown block being below the
oil-water contact.
At the
hairpin curve on U.S. 77, just 1/4 mile north of the Turner Falls
overlook, the Washita Valley fault has juxtaposed massive gray Arbuckle
limestone to the south and the Upper Pennsylvanian (or Permian) Collings
Ranch Conglomerate overlying truncated, steeply dipping beds (Figure
18). The road cut along nearby I-35 shows a synclinal fold in the
Collings Ranch Conglomerate. Arbuckle to Springer beds in the downthrown
block are in a tightly folded syncline. Less than one mile to the south,
the beds drilled (down to the Basal Oil Creek) in Placid #1 Geis well
are exposed on the surface.
In Southwest Sandy Creek Field (Area 6,
Figure 14 and Figure 19), two miles east of Davis, Permian rocks
unconformably overlie the Springer, which with the underlying strata are
present in fault blocks bounded by four northeast-striking normal
faults. Oil production from Bromide sand (Simpson) is in both the
upthrown and downthrown blocks of each fault. The oil-water contact in
each fault block is higher in the upthrown block toward the southeast.
Other producing zones in Southwest Sandy Creek Field include the
Sycamore, Woodford, Hunton, Viola, Basal McLish sand (Simpson) and Basal
Oil Creek sand, all of which crop out in the Arbuckle Mountains a few
miles to the south.
In the cross -section of
Figure 20, also from Southwest Sandy Creek Field area and
approximately perpendicular to cross -section of
Figure 19, tightly folded, complexly faulted strata are truncated by
a thick Permian section. The abrupt change in structure to the northeast
(from syncline to thrust-faulted anticline) corresponds to the boundary
between the Mill Creek Syncline and the Pauls Valley Uplift (to the
northeast), which formed during the Early Pennsylvanian Wichita Orogeny.
Figure 21 shows the location of a
cross -section of the Pauls Valley Uplift (Figure
22), with the Deese
unconformably on the Caney Shale. To the east, this Wichita unconformity
truncates older beds down to the lower part of the Viola. The
unconformity now dips to the west. The Deese and Hoxbar thin to the east
and onlap the unconformity.
Selected Bibliography
Ham, W.E., M.E. McKinley, et al., 1954,
Geologic map and sections of the Arbuckle Mountains, Oklahoma: Oklahoma
Geological Survey, Map GM 31 (revised by K.S. Johnson, 1990).
Harding, T.P.,1985, Seismic characteristics and identification of
negative flower structures, positive flower structures, and positive
structural inversion: AAPG Bull., v. 69, p. 582-600.
Miser, H.D., 1954, Geologic map of
Oklahoma: Oklahoma Geological Survey and U.S. Geological Survey.
Parker, E.C., 1959, Structure and lithology of the Springer in Southeast
Velma-Camp area, in Petroleum Geology of Southern Oklahoma, v. II: AAPG,
p. 227-248.
Reedy, H.J., and H.A. Sykes, 1959, Carter-Knox oil Field, Grady and
Stephens counties, Oklahoma, in Petroleum Geology of Southern Oklahoma,
v. II: AAPG, p. 198-219.
S&D, 1999, Disharmonic folds in Southern Oklahoma:
Revisited: Search and Discovery article #60004, v. 1, 1999
Schweers, F.P., 1959, Milroy Field, Stephens and Carter counties,
Oklahoma, in Petroleum Geology of Southern Oklahoma, v. II: AAPG, p.
220-226.
Tomlinson, C.W., 1952, Odd geologic structures in Southern Oklahoma:
AAPG Bull., v.36, p. 1820-1840.
Tomlinson, C.W., and William McBee, Jr.,
1959, Pennsylvanian sediments and orogenies of Ardmore District, in
Petroleum Geology of Southern Oklahoma, v. II: AAPG, p. 3-52.
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A paper of this type requires the
assistance of many friends. Bryan Sralla, a geologist who was in my
office for five years and is currently
employed with Coho Energy in Dallas, is
an outstanding stratigrapher and structural geologist. Bryan supported
and encouraged the preparation of this presentation. Charles Clarke, of
Ardmore, Okla., is a good friend and an outstanding draftsman who helped
with the original cross - sections and maps . Mike and Mary Allison of
Gainesville, Texas, gave their support. Mike is an outstanding geologist
and Mary constructed the original maps and cross - sections on her
computer. The typing was done by Kathy Means, with Professional Office
Services, of Ardmore, Okla.
The
paper was reviewed by Dr. Charles Gilbert, Professor of Geology and
Geophysics at the University of Oklahoma, who provided input and
suggestions; C. E. "Ed" Hannum, a friend and fellow geologist in
Ardmore, who recommended that this be prepared as a scientific paper;
Dr. Ray Brown, a geophysicist with the Oklahoma Geological Survey in
Norman; Dr. Bob Neman, a good friend, fellow rock collector and chairman
of the Department of Chemistry at East Central University, Ada,
Oklahoma, and by Dr. Tommy Thompson, a consulting geologist and good
friend from Boulder, Colo. Bob Northcutt, a friend and fellow geologist
from Oklahoma City, heard this as a presentation and suggested it might
be published in the Shale Shaker, the official publication of the
Oklahoma City Geological Society. This information has been presented to
the Ardmore Rotary Club, the Ardmore Optimist Club and to the geological
societies in Ardmore, Oklahoma City and North Texas, as well as Tulsa.
For a paper to be published, it needs
professional attention. The Noble Foundation of Ardmore has this talent.
My sincere thanks to Michael A. Cawley, president of the Noble
Foundation, for his support; to Joe Lobell, Communications Department
manager, for his consent; and to Sharon Burris, media and publications
specialist, who put this paper in its final form. My sincere thanks to
all.
It is my
hope that this information can be used by teachers, students, and anyone
who might be interested in the subsurface geology of this fabulous
planet on which we live.
Robert W. "Bob" Allen, a native
Oklahoman, is a professional geologist with over 50 years of geological
experience. For the last 46 years Bob has lived and worked in Ardmore,
Oklahoma studying the structure and stratigraphy of southern Oklahoma
and prospecting for oil and gas. Bob's particular area of interest
includes the surface and subsurface geology of the Arbuckle and Wichita
Mountains, and the Ardmore and Marietta basins.
Bob served in the U. S. Army during
World War II from 1943 to 1946. Following his Army service he attended
the University of Oklahoma where he earned a B.S. in Zoology in 1948 and
a B.S. in Geology in 1950.
After graduation from the University of
Oklahoma, Bob worked for Globe Oil and Refining Company in Oklahoma City
from 1949 until 1954 when he went to work for Continental Oil Company in
Ardmore, Oklahoma. Bob was Division Geologist for the Southern Oklahoma
Division of Continental Oil Company when he left them in 1962 to become
an Independent and Consulting Geologist in Ardmore.
Bob Allen
has been a leader and staunch supporter in the preservation of the
Ardmore Sample Cut and Library. Bob is a longtime member of the American
Association of Petroleum Geologists, the Oklahoma City Geological
Society, and the Ardmore Geological Society, who named him an Honorary
Life Member in 1988.
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