THE ORIGIN OF THE FAULTS, ANTICLINES, AND BURIED "GRANITE 

RIDGE" OF THE NORTHERN PART OF THE MID-CONTINENT OIL AND 

GAS FIELD. 

By A. E. FATH. 

INTRODUCTION. 

The structural geologist is ever confronted 

by the problem of the origin of the geologic 

features with which he deals. An understanding of their fundamental causes permits a better 

interpretation of their significance, which iJ?-

studies of natural resources, such as oil and 

gas, has a direct economic bearing. In regions 

where the rock folds and faults are of large 

magnitude the structural mechanics are generally apparent, at least in part, but in the MidContinent field, where but few of the anticlines 

and faults represent elevations of more than 

200 feet, the origin of these fea.tures is more 

obscure. These small rock folds and fractures 

have commonly been considered the distant effects of forces originating in the Ozark Mountains, the dominating structural feature of the 

region, but the difficulty of applying this explanation to the features that have come under 

the writer's observation has led to other considerations, which are presented in this ·paper. 

The need of understanding the origin and 

mechanics of the structural features in the MidContinent oil and gas field may be inferred 

from the fact that much of the oil and gas in 

this region occurs in localities where the structure of the containing rocks is favorable for 

its accumulation-that is, where there are anticlinal or domal flexures. In searching for new 

oil and gas pools it is therefore of paramount 

importance not only to know the structure of 

the surface rocks in the regions to be prospected 

but also to understand how the structural features exposed at the surface may differ from 

those which govern the accumulation of oil 

and gas in the deep-lying strata. 

In addition to the anticlines and domes there 

are, in places, many faults of the en echelon or 

offset type, grouped into remarkable parallel 

belts or series, the study of which suggested 

the fundamental principles on which the present discussion is based. Still another geologic 

feature of considerable significance in this 

region is a buried " granite ridge" trending 

northeastward from Butler County, Kans., to 

Pawnee County, Nebr. 

The alinements of these three features-the 

major anticlines, the fault belts, and the buried 

"granite ridge "-are remarkably parallel, and 

to the writer this parallelism indicates a genetic relationship. It is the purpose of this 

paper to point out this relationship and to 

present an interpretation of its meaning. 

REGIONAL GEOLOGY. 

Before the structural features are described 

in detail, a brief summary o:f the regional geology will be presented as a background for the 

discussion. Rocks of undoubted ·pre-Cambrian 

age, such as granites and quartzites, crop out at 

numarous places around the northern part of 

the Mid-Continent field, .in the St. Francis 

Mountains of southeastern Missouri, the Arbuckle and Wichita mountains o:f southern 

Oklahoma, the Rocky Mountains of New Mexico, Colorado, and Wyoming, the Black Hills 

in southwestern South Dakota, and the Sioux 

quartzite area of southeastern South Dakota, 

southwestern Minnesota, and northwestern 

Iowa. These outcrops probably do not represent rocks of precisely the same age, but 

they represent the ancient basement complex 

upon which all the Paleozoic stratified rocks 

of the Mid-Continent region were deposited. 

Within the oil-field region of eastern Kansas 

similar crystalline rocks have been found at 

comparatively shallow depths in holes drilled 

for oil.1 (See Pl. XIV.) Such drill holes are 

1 Taylor, C. H., The granites of Kansas: Southwestern 

Assoc. Petroleum Geologists Bull., vol. 1, pp. 111-126, February, 1917. Powers, Sidney, Granite in Kansas: Am. Jour. 

Sci., 4th ser., vol. 44, pp. 146-150, August, 1917. Wright, 

Park, Granite in Kansa.s wells: Am. Inst. Min. Eng. Bull. 

128, pp. 1113-1120, August, 1917. Moore, R. C., and 

Haynes, W. P., The crystalline rocks of Kansas, in Oil and 

gas resources of Kansas : Kansas Geol. Survey Bull. 3, pp. 

140-173, 1917. Moore, R. C., Geologic history of the crystalline rocks of Kansas : Am. Assoc. Petroleum Geologists 

Bull. 2, pp. 98-113, 1918. 

75 
76 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1920. 

Generalized section of formations in eastern Kansas. 

Geologic age. Group. Formation. Principal character. 

Wellington shale. . . . . . . . . . . Shale ...................... . Sumner group ..... Marion formation ........... Shale, limestone and con- glomerate. 

Winfield formation ........ . Limestone and shale ...... . Doyle shale ................ . Shale .............. -........ . 

Thickness 

(feet). 

500-800 

150 

Permian •.•......... Chase group ....... . Fort Riley limeetone ....... . Florence flint .............. . Limestone ................. . Cherty limestone ..... -...... . 

8-25 

60-90 

40-50 

20-35 

57-70 

28-50 

Matfield shale ............. . Shale ...................... . Wreford limestone ......... . Limestone .... .' ............ . 

C "lG Garrison formation ......... Shale and thin limestones .. ouncl rove group Cottonwood limestone ....... Limestone ......... -... -----

Eskrid~e shale. ~ .......... . Neva limestone ............ . Shale ...................... . Limestone ................. . Elmdale formation ......... . Shale and thin limestones .. 

Wabaunsee group ... Americus limestone ....... . Admire shale ............. . Limestone ................. . Shale ...................... . Emporia limestone ........ . Willard shale ............. . Limestone ................. . Shale ...................... . Burlingame limestone ...... . Limestone ................. . 

Scranton shale ............ . Shale ...................... . Howard limestone ........ . Limestone ................. . Shale ...................... . Limestone ................. . Shale ........... ~ .......... . Limestone ................. . Shawnee group .... 

Severy shale .............. . Topeka limestone .... ~ ..... . Calhoun shale ............. . Deer Creek limestone ...... . Tecumseh shale ........... - Shale ...................... . Limestone ................. . Shale ...................... . Lecompton limestone ...... . Kanwaka shale ........... . 

135-150 

5-12 

30-40 

10 

130 

8 

300 

9 

45-55 

7-12 

160-200 

3-7 

40-60 

20-25 

25-50 

20-30 

40-70 

15-30 

50-100 

Oread limestone........... Limestone................... 50-70 

D 1 Lawrence shale ........... - Shale....................... 150-300 · oug as group.····· Iatan limestone ........... - Limestone.................. 3-15 

Pennsylvanian...... Weston shale .............. Shale....................... 60-100 

--1-----

Stanton limestone .......... Limestone.................. 20-40 

L · p Vilas shale. . . . . . . . . . . . . . . . . Shale........... . . . . . . . . . . . . 0-125 

ansmg grou · · · · · · Plattsburg limestone ...... -- Lii~testone ... -- ·. -.- ---· --.. 4-80 

Lane shale.. . . . . . . . . . . . . . . . Shale............. . . . . . . . . . . 50-150 

lola limestone ............. . Limestone ................. . Chanute shale ............ . Shale ...................... . Drum limestone ........... . Limestone ..... -............ . 

Kansas City group .. Cherryvale shale .......... . Winterset limestone ....... . Galesburg shale ........... . Bethany Falls limestone ... . Ladore shale .............. . 

Shale ................ _-_ .... . Limestone ................. . Shale ...................... . Limestone ................. . Shale ..............•........ Hertha limestone ......... . Limestone ................. . 

Dudley shale. . . . . . . . . . . . . . Shale .................... . Pleasanton group... Parsons formation. . . . . . . . . . Shale and limestone ....... . Bandera shale ............. Shale .................... . 

Pawnee limestone. . . . . . . . . . Limestone ................. . Henrietta group..... Labette shale. . . . . . . . . . . . . . Shale ...... ~ ....... _ ....... . Fort Scott limestone ........ Limestone ................. . 

Cherokee shale...... . . . . . . . . Shale .... ' .................. . 

0-40 

25-100 

0-80 

25-125 

5-30 

5-60 

4-23 

3-40 

0-22 

160 

80 

60-140 

45-52 

20-120 

so 

350-700 

Unconiormity------II----------------I-------------------1---------------------!---------

Mississippian ........ . Boone limestone ........... Limestone ................. . 300-500 

Unconformity------I----------------I----------------------I------------------------1----------

0rdovician and Cam- Dolomite and sandstone..... 1, ooo-2, 200 

brian. 

Unconfonnuy------~-------------------·------------------I-----------------------1-----------

Pre-Cambrian ..........•..................................... , . . . . . . Granite ................... . 
FAULTS, ANTICLINES, AND BURIED "GRANITE RIDGE" OF MID-CONTINENT FIELD. 77 

generally termed "granite wells." The crystalline basement thus encountered is much shallower than had previously been thought possible. In places it lies less than 1,000 feet below 

the surface, and in these localities it is directly 

overlain by upper Pennsylvanian rocks, and 

these in turn by Permian rocks. In the light of 

available evidence it now seems probable that 

the granite thus discovered indicates the presence of a buried " ridge " (named the Nemaha 

Mountains by Moore and Haynes), which probably formed a low island in the early Pennsylvanian sea and was entirely covered by later 

sediments. 

The Paleozoic sediments overlying the preCambrian basement consist in general of shales, 

sandstones, and limestones of Cambrian, Ordovician, Mississippian, Pennsylvanian, and Permian age, whose subdivisions are given in more 

detail in the accompanying table. A feature of 

this stratigraphic section which deserves 

special attention is the contrasting character 

of its lower and upper parts. The pre-Cambrian cryst;tlline rocks are strong and are. regarded as competent to transmit deformational 

stresses through long distances. The Cambrian, Ordovician, and Mississippian rocks are 

less strong but still somewhat competent, especiaUy in contrast to the weak Pennsylvanian 

and Permian rocks, which consist predominantly of soft plastic clay shales and are 

therefore relatively incompetent to transmit 

stresses. 

Located principally in Missouri but extending also into adjacent States is the Ozark uplift, 

which is the dominating structural feature in 

the northern part of the Mid-Continent field. 

The formation of this uplift had two distinct 

phases, the first in late Mississippian or early 

Pennsylvanian time and the second in postPaleozoic time. Erosion has removed much of 

the Paleozoic sediments involved in this uplift, 

and in places the pre-Cambrian rock is exposed. 

The outcropping rocks of eastern Kansas and 

northeastern Oklahoma, on the flanks of the 

uplift, dip gently westward at a rate normally 

between 15 and 80 feet to the mile. Their 

present attitude is due directly to the disturbance that produced this uplift, but because 

they are not at tbe heart of the disturbance 

their westward dip is generally spoken of not 

43595°-21-7 

as a part of the Ozark uplift itself but as the 

Prairie Plains monocline. 

Cambrian, Ordovician, and Mississippian 

strata were involved in both phases of this 

widespread Ozark deformation, but the overlying Pennsylvanian and Permian formations 

were affected only by the post-Paleozoic disturbance. The time occupied by the first de£-

ormational period is represented in an extensive erosional unconformity, with no marked 

angular divergence between the Mississippian 

and Pennsylvanian series. Although the first 

phase of the Ozark deformation took place before the deposition of the Pennsylvanian strata, 

slight deformational movements, probably of 

the nature of readjustments, continued intermittently-that is, concurrent with deposition 

-until post-Paleozoic time, when the second 

and more widespread stage of the disturbance 

occurred. These slight movements of readjustment are significant and will be referred to 

later. 

ORIGIN OF THE FAULTS. 

The writer's interest in the origin of the 

structural features in the Mid -Continent oil 

field was first aroused in trying to determine 

the cause of the belts of en echelon faults. in 

the Bristow quadrangle, Creek County, Okla. 

The preliminary ~eport 1 on this area attempted 

no explanation; in fact, at that time the writer 

had none. However, during the preparation 

of this report the origin of the faults had been 

discussed with R. H. Wood, a colleague interested in the Hominy quadrangle, immediately-to the north, who advanced the idea of 

torsional forces operating along lines of weakness. Because no adequate source of these 

forces was at that time apparent, no logical 

conclusions were reached. The writer is most 

fantiliar with the faults in the Bristow quadrangle, and therefore in this discussion the 

detailed descriptions apply more directly to 

those occurring in that area. Nevertheless, it 

is believed that the descriptions are equally 

applicable to all similar faults in the region. 

The faults in the northern part of the MidContinent oil and gas field, as described by 

1 Fath, .A. E., Structure of the northern part of the Bristow quadrangle, Creek County, Okla.: U. S. Geol. Survey 

Bull. 661, pp. 69-99. 1918. 
78 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1920. 

several authors,1 are shown on Plate XII. They 

lie in a broad northward-trending zone, which 

crosses Okfuskee, Creek, Pawnee, and Osage 

counties, Okla., and probably extends into 

Hughes and Seminole counties on the south and 

into the State of Kansas on the. north. These 

faults, which locally modify the westward dip 

of the strata, are of the normal type and are 

noteworthy not only becau~e of their approximate parallelism but also because of their 

grouping into belts or series which also have 

a parallel trend, although in a different direction. Most of the individual faults trend about 

N. 20°-45° W. and lie en echelon to one another 

in such a manner that the linear belts or series 

into which they are grouped trend from north 

toN. 25° E., or roughly at an angle of 45° with 

the trend of the faults. The faults are of minor 

magnitude. both in vertical displacement and 

areal extent, the largest stratigraphic throw 

observed in the Bristow quadrangle amounting 

to about 130 feet and the greatest length to 

about 3-l miles. As a general rule they are 

straight, but some have slightly curved traces. 

Where they cut' sandstone beds slickensided 

surfaces are developed, and these indicate that 

some of the fault planes dip southwest and 

some northeast, at angles which range between 

50° and 65 ° from the horizontal. A variation 

in the amount of dip of a fault plane may account for its curved trace. 

As mentione<1: above the faults are normalthat is, the downthrow is in the direction of 

the hade-and hence the forces that caused 

the individual fractures were probably tensional in nature and operated in a direction 

normal to their trend, or N. 45°-70° E. On 

1 Fath, A. E., and Heald, K. C., Faulted structure in the 

vicinity of the recent oil and ga.s development near Paden, 

Okla. : Oklahoma Geol. Survey Bull. 19, pt. 2, pp·. 353-360, 

1917. 

Fath, A. E., and Emery, W. B., Structural reconnaissance 

in the Okemah-Tiger Flats region, Okfuskee and Okmulgee 

counties, Okla.: U. S. Geol. Survey Bull. - (in preparation). 

Fath, A. E., Structure of the northern part of the Bristow 

quadrangle, Creek County, Okla.: U. S. Geol. Survey Bull. 

661, pp. 69-99, 1918. 

Fath, A. E., Geology of the Bristow quadrangle, Creek 

County, Okla.: U. S. Geol. Survey Bull. - (in preparation). 

Wood, R. H., unpublished report on the Hominy quadrangle, Creek, Pawnee, Tulsa, and Osage counties, Okla. · 

Buttram, Frank, The Cushing oil and gas field, Okla. : 

Oklahoma Geol. Survey Bull. 18, 1914. 

Heald, K. C., Geologic structure of the northwestern part 

of the Pawhuska quadrangle, Okla. : U. S. Geol. Survey Bull. 

691, pp. 57-100, 1918. 

Heald, K. C., and others, Structure and oil and gas resources of the Osage Reservation, Okla. : U. S. Geol. Survey 

Bull. 686, separate chapters issued in 1918 and 191U. 

the other hand, th;e linear grouping of these 

fractures into belts and their general uniform 

development suggest that the faults of any one 

series were cau~d by forces that operated in a 

direction parallel to the series-that is, north 

to N. 25° E. The question arises: How can 

horizontal forces operating in weak strata like 

those forming the Pennsylvanian series of this 

region produce belts 50 miles or more in length 

of diagonal tensional faults~ To suppose that 

the controlling forces were transmitted by the 

weak Pennsylvanian strata is unreasonable, 

for t~ stresses would have been relieved by 

adjust:r;nent within· the mass. 

If the upper few thousand feet of strata in 

this region are too weak and incompetent to 

transmit such horizontal forces some other 

agent must be sought. Lying at some unknown 

depth beneath the surface of this region are 

the massive granites and quartzites and their 

associated rocks which constitute the qasement 

complex, and above them are massive limestones and sandstones such as are known in the 

St .. Francis, Arbuckle, Wichita, and other 

mountain ranges surrounding this region., A 

granite ridge is known to underlie the Permian 

and Pennsylvanian strata in a part of northeastern Kansas. The crystalline rocks of the 

basement complex are fully competent to transmit earth forces, and they are more closely related than the overlying rocks to deep-seated 

deformational movements of the earth's crust. 

These competent rocks could transmit horizontal forces, such as movements along fault 

planes or shear zones, through considerable distances especially if they were overlain by· a 

heavy load of sediments. An attempt will be 

made to explain the faults of the northern MidContinent region by postulating that the controlling or. master forces that produced the 

fault belts at the surface through the long distance over which they occur operated in a direction parallel to those belts and were transmitted in a horizontal direction by the massive 

competent rocks that lie at considerable depth 

beneath the surface. It is believed to be a 

reasonable speculation that the faults of the 

Mid-Continent region are the natural surface 

expression in overlying weak rocks of such 

deep-seated horizontal movements. 

As the strata overlying the deep-seated beds 

are relatively weak and incompetent their deformation would differ from that of the com-
U. 8, GEOLOGICAL SURVEY PROFESSIONAL PAPER 128 PLATE XU 

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R.Z E. R.3 E. R.4 E. R.SE,. R.GE.. R.7 E.. R. 8 E. R.9E. R.IOE.. R.II.E. R. IZ. (.. RJ3E. 

5 0 5 10 IS Miles 

SKETCH MAP OF A PART OF NORTHEASTERN OKLAHOMA SHOWING THE DISTRIBUTION OF EN ECHELON FAULTS AND, IN OSAGE 

COUNTY, A PREDOMINANT NORTH~RLY ALINEMENT OF THE ANTICLINES AND DOMES. 

The heavy short lines are the faults, the stippling represents the approximate areas of anticlinal and domal closure (closed contours), and the dashea either indicate 

liDes of folding connecting the anticlines and domes or suggest an alioement of the anticlines and domes OODI.IeOted. Mud:& of the blank. area on this lll8p I'EJpftii!I8Dts lack of information. . 

• 
FAULTS, ANTICLINES, AND BURIED '' GRANITE RIDGE'' OF MID-CONTINENT FIELD. 79 

petent beds. Instead of breaking or shearing 

along a nearly vertical plane or zone parallel 

to a fracture or shear zone in the underlying 

FIGURE 4.-A circle on a rubber eraser (A), elongated by distorting the eraser (B). The direction of elongation is the 

direction of tension. 

granites along which a horizontal movement 

has taken place, they would bend or be dragged 

over the displaced competent beds, and tension 

would be produced in these layers at an angle 

of · about 45 ° to the direction of movement. 

This result may be illustrated by drawing a 

circle on one side of. a rubber eraser or other 

flexible substa.nce and distorting the eraser by 

a force acting in the direction shown in figure 

4. The circle on the eraser will also be distorted, being elongated in a diagonal direction 

at an angle of about 45 ° with that of the distorting force and contracted in a direction at 

right angles thereto. In other words, the distorting force may be resolved into two forces 

at right angles to each other, one producing 

elongation in the mass and the other producing 

contraction. The same effect accompanied by 

the production of fractures normal to the tension is pictured in Plate XIII, which shows 

an undeformed flat piece of modeling clay 

partly pierced by several conical holes along 

a medial belt and the same piece of clay after 

being deformed by a force operating in the 

direction indicated by the arrow. The ro-q.nded 

holes have been elongated in the 'direction of 

tension and contracted in the direction of compression. Fractures, which have been centralized by the weakening of the mass at the holes, 

have been produced parallel to the direction of 

compression and are pulled apart in the direction of tension. 

The fractures produced in the rocks immediately overlying the harder competent rocks in 

which the horizontal displacement occurred 

would be irregular breaks which would remain 

open fissures if it were not for the adjustment 

to these open spaces that would immediately 

take place in the thick series of soft formations. 

In this adjustment the fractures would be 

closed up by one side or the other slumping or 

giving way, producing a vertical displacement of the beds on opposite sides of the fissure 

somewhat similar to the relation of adjacent 

members of a tumbled row of toy blocks, as 

shown in figure 5-that is, there would be a 

normal fault. The fissuring itself would cause 

no displacement of the strata, but the adjustment would. Although the deep-lying fractures may · be irregular breaks, their upward 

extensions into the overlying less-loaded material would probably be straighter and at the 

surface would be represented by regular normal faults. 

The application of this explanation to the 

faults in the Mid-Continent field shows that 

the direction of the movement in the deep-lying 

competent rocks must have been along the belts 

of faults, the territory on the east side of each 

fault belt moving northward relative to the 

west side. If the faulted region is considered 

as a whole, in which each unfaulted strip on 

the east of a fault belt moved northward relative to its respective strip on the west, the 

general movement may be likened to a re- -

gional shearing, the slip planes in the granite I 

B 

FIGURE 5.-Diagrammatic sketch to illustrate normal faulting. A, Two blocks slightly separated; B, the same blocks 

tumbled. 

basement being marked by the belts of faults 

in the weak and incompetent surface beds. 

It is patent that if the incompetent beds 

were sufficiently thick faulting of this type 
80 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1920. 

would be gradually dissipated and would fail 

to reach the surface. It is therefore probable 

that the Pennsylvanian rocks beneath the surface contain many such fault zones, which 

failed to reach the surface because the movements that initiated them were not as great as 

those which produced the faults that now show 

at the surface. If this is so the displacements 

of the faults observed at the surface increase 

with increasing depth until they reach the 

competent rocks in which the controlling force 

operated. 

ORIGIN OF THE ANTICLINAL FOLDS. 

Anticlines are generally regarded as due to 

the buckling of strata accompanying compression at right angles to the axes of the folds. In 

view of the weakness of the rocks in which the 

folding has taken p ace in the Mid -Continent 

region this explanation does not seem adequate, 

and another line of reasoning may be followed. 

An extensive series of faults or shear zones in 

the pre-Cambrian basement rocks has been 

postulated in explaining the belts of faults, 

but the readjustment along these ancient lines 

of weakness probably was not everywhere horizontal. Vertical movement along these breaks 

would probably be even more comrr'!on, and the 

effect in the overlying incompetent beds would 

be quite different from the belts of faults described above. It is a commonly recognized 

fact that faulting resolves itself in distance into 

folding, and so in this region although the 

lowermost incompetent beds would be faulted 

similarly to the competent rocks the faulting 

would diminish in intensity away from the competent rocks, and at a 'sufficient distance would 

resolve itself into folding, after the manner 

shown in figure 6. In the Eldorado oil and gas 

field, Kansas, there is good evidence that in 

places the deeper rocks are faulted wherea~ the 

surface rocks are simply folded. 1 Although 

folding of ·this type seems to explain satisfactorily the origin of the anticlines in the 

northern part of the Mid-Continent field, it 

does not fully explain many of their attendant 

phenomena. 

Nevertheless, to carry this line of reasoning 

further, the question arises: Do the anticlinal 

folds in this region indicate displacements 

1 A report on the Eldorado field is now being prepared 

by the writer. 

along extensive master faults or shear zones in 

the basement complex comparable to those 

which are believed to have produced the belts 

of en echelon {a ults as indicated above~ In 

Plate XIV and the Osage County part of Plate 

XII are shown numerous well-known axes of 

extensive anticlinal folding. It is to be noted 

A 

c FIGURE 6.-Diagrammatic sketches illustrating progressive 

stages in the upward dissipation O·f a fault and its resolution into anticline folding. A, The fault affects all the 

strata; B, bed g has been deposited upon the faulted :md 

flexed beds a to f J. C, after a later additional movement 

along the same fault bed f is considerably more flexed than 

bed g. 

that they are segregated into distinct belts extending across the region and that they are not 

only parallel to but also comparable in length 

to the belts of en echelon faulting. Moore 2 

states that the " granite wells " extending from 

Pawnee County, Nebr., southwestward to But2 Moore, R. C., Geologic history of the crystalline rocks of 

Kansas: Am. Assoc. Petroleum Geologists Bull. 2, p. 102, 

1918. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 128 PLATE XIII 

A. B. 

A FLAT MASS OF MODELING CLAY PIERCED BY SEVERAL CONICAL HOLES, BEFORE AND AFTER BEING 

DEFORMED. 

A shows the mass undeformed; B shows the mass after being deformed by forces operating in the direction of the arrow. The corru- gations along the edges of the clay in Bare impressions of the gripping mechanism by which the mass was deformed. 
FAULTS, ANTICLINES, AND BURIED "GRANITE RIDGE" OF MID-CONTINENT FIELD. 81 

ler County, l(ans., were drilled on anticlines 

belonging to a single belt of folding. This 

belt continues southward and includes the anticlines of the Eldorado 1 and Augusta 2 oil 

fields, thus extending nearly across the State 

· of Kansas. " Granite wells " have been reported in the Eldorado field, but the details of 

location and depth could not be obtained for 

inclusion in this paper. 

Paralleling this extensive belt to the south 

and east are the extensive anticlines and series 

of shorter anticlines of Cowley County, l(ans.,3 

and the Oklahoma counties of Kay,4 Garfield,5 

Noble,6 and Creek 7 shown on Plate XIV, and 

the series of shorter anticlines which are typically developed in Osage County, Okla.,8 as 

shown on Plate XI~. Many of the anticlines 

and domes of Osage County, Okla .. , appear 

also to be related by a secondary east-west alinement which the present discussion does not · 

attempt to explain. Notwithstanding such discrepancies, it is believed that if the structure 

of the entire Mid-Continent field were known 

in detail, many more lines of folding could be 

added to those shown on Plates XII and XIV, 

and these would more convincingly indicate 

the presence of extensive parallel zones of 

weakness, which have yielded to pressure, in 

the deep-seated basement rocks. 

In assuming that these belts of folding are 

due to vertical displacements along master 

faults or shear zones in the basement complex, 

it must not be concluded that the displacement 

along any such fault would be of equal magnitude throughout its extent, or in other words 

that the result of such a displacement is a sin1 Report in preparation by the writer; also McDowell, 

J. C., Geology in its relation to the oil industry: Am. Min. 

Congress Proc., vol. 19, map on p. 297, 1917. 

2 :McDowell, J. C., op. cit., map' on p. 294. 

s Observed by the writer during a reconnaissance examination. 

4 Trout, L. E., Petroleum and natural gas in. Oklahoma: 

Oklahoma Geol. Survey Bull. 19, pt. 2, pl. 23, 1917. 

5 Hager, Dorsey, Belt, B. C., and Haworth, Huntsman, 

Petroleum and natural gas in Oklahoma : Oklahoma Geol 

Survey Bull. 19, pt. 2, pl. 18, 1917. 

e Fath, A. E., An anticlinal fold near Billings, Noble 

County, Okla.: U. S. Geol. Survey Bull. 641, pl. 9, 1916. 

7 Beal, C. H., Geologic structure in the Cushing oil and 

gas field, Okla., and its relation to the oil, gas, and water: 

U. S. Geol. Survey Bull. 658, pl. 5, 1917. 8 Heald, K. C., The oil and gas geology of the Foraker 

quadrangle, Osage County, Okla. : U. S. GeoJ. Survey Bull. 

641, pl. 2, 1916; Geologic structure of the northwestern 

part of the Pawhuska quadrangle, Okla.: U. S. Geol. Survey 

Bull. 691, pl. 13, 1918. Heald, K. C., and others, Structure and oil and gas resources of the Osage Reservation : 

U. S. Geol. Survey Bull. 686, plates in the chapters that 

have ap·peared to the date of writing, Apr. 15, 1919. 

gle continuous and uniform anticline in the 

surface rocks. The displacements are probably 

more or less local in extent. A 100-foot displacement at any one place might disappear 

within a short distance, and the resulting anticline in the-overlying beds would have definite 

termini. The length of such an anticline is a 

measure not of the extent of the fault or shear 

zone but merely of the distance along its course 

through which noticeable vertical displacement has occurred. There may be recurrent 

vertical displacements at intervals along these 

lines or zones of weakness, forming a long 

linear series of anticlines, such as those in the 

beds overlying the buried "granite ridge" 

which extends practically, if not entirely,_ 

across the State of Kansas and in the parallel 

belts of short anticlines, such as those of Osage 

County, Okla., shown on Plate XII. It is possible that where these displacements die out 

rapidly in both directions the resultant :fold in 

the overlying sediments will not be elongated 

into an anticline but will assume the more local 

form of a dame. A displacement in the reverse 

direction would cause a depression or syncline, 

and short synclines may alternate with domes 

along any one line of movement. Such relations have been mapped at numerous places in 

Osage County, Okla. 

To form the extensive anticlinal and fault 

belts of the northern part of the Mid-Continent 

oil and gas field, a regional series of essentially 

parallel master faults or shear zones must have 

been present in the basement complex. Such 

regional series 8f parallel faults are not uncommon but: are probably for~ned only during 

great orogenic disturbances. As no deformation of this magnitude is known to have taken 

place in the northern Mid-Continent region 

since the beginning of Paleozoic time, as indicated by the rocks of the region, the faults 

or zones of weakness postulated as present in 

the basement complex of this region must have 

originated in pre-Cambrian time. It is possible that these master faults or shear zones 

were formed either by thrust faulting or by 

normal faulting, but it is believed that the late 

displacements along these ancient lines which 

caused the faulting and dip reversals in the 

Pennsylvanian and Permian strata were merely 

a relatively late readjustment along the ancient 

fault planes, whether those were thrust or 

normal faults. 
82 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1920. 

Slight deformational movements incident to 

the Ozark disturbance occurred intermittently 

during the Pennsylvanian and Permian epochs. 

If the parallel system of faulting in the basement complex existed throughout this time, 

these intermittent movements probably took 

place along the postulated zones of weakness. 

The lower Pennsylvanian strata were therefore 

involved in movements along the master faults 

prior to the deposition of the higher beds. If 

such movements occurred at repeated intervals, 

the lowermost beds would have been involved 

in numerous deformations and the successively 

higher beds in correspondingly fewer deformations. The lower beds would thus be more 

_folded or faulted than the higher beds, and it 

is therefore possible that in the deeper Pennsylvanian strata there are folds and faults that 

have no corresponding structural features in 

the surface rocks, which were deposited after 

the specific movement took place. This theoretical condition is illustrated in figure 6, B 

and C, and examples of its existence in the 

Mid-Continent region are given below. 

It is further to be noted that the structure in 

the surface rocks represents the nature of the 

latest movement along the master faults, which 

occurred sine~ these surface rocks were deposited. En echelon faults, due to horizontal 

displacements in early Pennsylvanian time, 

may therefore exist in the deeper rocks, but a 

vertical movement of post-Permian time along 

the same faults would have produced only folding in the surface rocks. Further, a combined 

horizontal and vertical displacement may produce both faulting and folding. Numerous 

occurrences of such combined types of structure are known, such as the Catfish anticlines 

of the Bristow quadrangle and many others 

in Osage County, Okla. 

It is still further to be noted that where sev· 

eral movements have occurred along a master • 

fault., some of these displacements may have 

been in opposite directions and compensated 

each other, with the result that a lower bed 

would show less displacement or folding than 

a higher bed. Such reversal of movement along 

an otherwise normal fault is indicated in the 

faults near Paden, Okla.1 

The general increase in amount of folding 

with increase in depth previously referred to is 

proved by the results of drilling in the oil and 

gas fields situated on the anticlinal folds. The 

first,published demonstration of this feature of 

which the writer ig a ware referred to the 

Cushing oil field, in Oklahoma,2 where three 

intervals of deformation are indicated through 

a 2,600-foot series of sediments. The follow· 

ing table, compiled from the structure maps 

of Beal's report, shows this increasing amount 

of folding from the surface down ward to the 

Bartlesville sand. The greater folding with 

increasing depth is very well shown, with the 

exception of the discrepancy between the 

Wheeler and Layton sands on the Mount 

Pleasant and Shamrock domes, which may 

be explained by a pre-Layton local reversing movement similar to that indicated at 

Pedan but far more highly developed. The 

increase in amount of folding between the 

surface rocks and the Layton sand is most 

marked. 

Increased amount of folding with increasing depth in the Cushing oil and gas field, as shown by amount of closure. 

Closure (feet). 

Approxi- Drumright Mount Pleas- mate depth 

(feet). Dropright dome ~s ant dome (as Shamrock 

dome. distinct om distinct frOm 

Mount dome. Pleas- Shamrock 

ant dome). dome) .. 

Surface rocks ............................... ........................ 75-100 15-25 5o- 75 75-100 

Layton sand .................. _ ..... _ .... _ . _ 1,350 175-200 15-25 300-325 25o-275 

Wheeler sand ..... _ ... ~ .... _ . _ ... ______ . _ .. 2,100 20Q-225 25-50 250-275 100-125 

Bartlesville sand_ ... __ .. __ . _ ...... _ ........ 2,550 20Q-250 5Q-75 275-300 175-200 

_1 _F~th, A. E., and He~d, K. C., Faulted structU:re in the 1 ll Beal, C. II., Geol.ogio structure in the Cushing oil and 

vicmity of the recent 011 and gas development near Paden, I gas field, Okla., ·and 1ts relation t() the oil, gas, and water: 

Okla.: Oklahoma Geol. Survey Bull. 19, pt. 2, pp. 358- U. S. Geol. Survey Bull. 658, pp·. 21-35, 1917. 

359, 1917. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 128 PLATE XIV 

95 

~-------. 

.J_j I 

G- I SEDGWICK I 

~-----+· 

R-·1 SUMNER i I I 

A G E 

10 0 10 20 30 40 Miles 

SKETCH MAP OF EASTERN KANSAS AND NORTHEASTERN OKLAHOMA, SHOWING DISTRIBUTION OF "GRANITE 

WELLS" (BLACK DOTS) AND AXES OF SEVERAL EXTENSIVE ANTICLINAL FOLDS (HEAVY BLACK LINES). 
FAULTS, ANTICLINES, AND BURIED "GRANITE RIDGE" OF MID-CONTINENT FIELD. 83 

The writer has found the same condition to 

prevail in the Eldorado fie!d of Butler County, 

Kans.1 The following advance information 

corroborates the increase in amount of folding 

with depth. 

Inereased a~unt of folding with inereasing depth in the 

Eldorado ml and gas field as "Shown by the amount of 

closure. 

Closure (feet). 

Wilson I Chesney Oil Hill 

dome. I dome. dome. 

Surface rocks ................ 40 20 30 

660-foot sand ............... 60+ 40 50 

Stapleton sand (2,400 feet) ... 100+ SO+ 80 

This increased amount of folding with increasing depth and the consequent possibility 

that well-developed folds exist in oil-bearing 

sands without any corresponding flexure in the 

surface. rocks are of great economic significance. Oil and gas may accumulate in such 

places where there is little or no folding in the 

surface rocks and where the conditions can not 

be determined by structural geologic investigations in advance of prospecting. This explanation may account for many of the smaller 

pools in localities where the rocks at the surface show no favorable structure. The absence 

of anticlinal folding in the surface rocks, therefore, doe~ not absolutely condemn any locality 

for its oil and gas prospects. 

As before mentioned, this explanation of the 

origin of the anticlines of the northern MidContinent oil and gas field does not account for 

all their attendant phenomena. It is believed, 

nevertheless, that it does account for a considerable part of the causes which formed 

them. Some of the principal features which 

are not accounted for in this explanation are as 

follows: (1) The distinct downward buckling 

of the surface strata on the east sides of the 

postulated deep-lying faults, instead of their 

simple dropping (and thereby the simple reversing of the dip of the strata). (2) The apparent. complete absence of evidence showing 

that any of the vertical displacements along 

the postulated deep-seated faults or shear zones 

were sufficiently large to break entirely through 

1 Report in preparation. 

the sedimentary rocks and show at the surface 

as faults. This is particularly striking along the 

" granite ridge," where the overlying sedimentary rocks are comparatively thin, less 

than 1,000 feet thick in places, and where the 

movement in the sedimentary rocks was sufficient to cause reversed dips for 200 feet or more 

vertically. (3) The divergence of some of the 

anticlinal axes from the supposed direction of 

the governing deep-seated fault zones in· Osage 

County, Okla., as shown on Plate XII. (4) 

The secondary or east-west relation of many 

of the folds in Osage County, also shown on 

Plate XII. 

ORIGIN OF THE BURIED" GRANITE RIDGE" 

OF KANSAS.1 

The relations of the sedi~entary strata to 

the" granite ridge" indicate that the ridge did 

not come into existence until post-Boone time, 

for in eastern Kansas the Mississippian formations contain no clastic material such as a 

granite land mass near by would supply. 

Furthermore, the ridge is flanked and overlaid 

by Pennsylvanian strata; hence it is thought 

that the ridge was elevated during the interval 

of widespread erosion between the Mississippian and Pennsylvanian epochs. 

With a postulated series of faults or other 

lines of weakness formed in the old rocks in 

pre-Cambrian time, the origin of the " granite 

ridge" of eastern Kansas can be readily explained as follows : A vertical movement occurred along one of these lines of weakness in 

late Mississippian or early Pennsylvanian 

time, and the displacement was sufficiently 

large to raise the up-faulted block above the 

Pennsylvanian seas, so that an elongated island 

was formed. This explanation conforms with 

Moore's hypothesis 2 as to the origin of this 

ridge and at the same time associates it with a 

regional series of fissures in the basement complex. 

The more recently discovered granite in a 

well in Riley County, Kans., may indicate the 

presence of a second buried "granite ridge" 

which may parallel the one previously known. 

1 No detailed description of the " granite ridge" will be 

undertaken here. The available evidence has been comprehensively summarized by Moore and Haynes (op. cit.). 2 Moore, R. C., Geologie history of the crystalline rocks of 

Kansas: Am. Assoc. Petroleum Geologists BulL 2, pp. 105-

106, 1918. 
84 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1920. 

SUMMARY. 

The parallelism of the fault belts, the anticlinal folds, and the buried " granite ridge " of 

the northern part of the Mid-Continent oil and 

gas field points to a relationship in origin. 

. The faults, by their character and grouping, 

furnish the best evidence of the common cause 

by indicating definite lines of weakness, not in · 

the incompetent strata in which they are found 

but in the strong rocks of the basement complex. Ho:tizontal movements along these lines 

of weakness in the deep-lying rocks, with the 

consequent drag of the overlying weak sediments, would tear the lower parts of these sediments along a/narrow belt parallel to the deepseated movements, and short fractures would 

open which would trend at an angle of about 

45 o with the direction of the movements. The 

adjustment of the overlying w~ak strata to 

these fractures would result in the belts of 

short normal faults characteristic of the 

region. 

Vertical displacements along these same lines 

of weakness in the basement complex would 

produce folds in the overlying Paleozoic sediments parallel to the lines of faulting. AIthough it is not clear how such disturbances 

would produce all fhe features observed in the 

Mid -Continent anticlines, this explanation is 

offered as a suggestion of the way in which 

the anticlines themselves were formed. 

Of special economic importance is the fact 

that deeply buried oil and gas bearing sands are 

generally more intensely flexed into anticlines, 

domes, and synclines than the surface rocks, 

and it is possible that in places the oil and gas 

bearing strata may be folded without the surface rocks being noticeably deformed. As a 

consequence oil and gas pools may occur in 

these underground flexures where the surface 

rocks do not show favorable structure. 

The buried "granite ridge " of Kansas may 

be similarly explained as the result of a large 

vertical displacement which occurred in late 

Mississippian or early Pennsylvanian time 

along one of the lines of weakness in the basement rocks. 

In conclusion the writer wishes to acknow ledge many suggestions anq helpful criticisms 

received from his colleagues in the United 

States Geological Survey; in particular the 

assistance of A. F. Melcher in developing the 

models pictured in Plate XIII.