Brighan Young University Geology Studies

GEOLOGY I YOUNG STUDIES f UNIVERSITY Volume 12 December 1965 r' r' CONTENTS

Thrusting in the Southern Wasatch Mountains, Utah ...... Michael J. Brady 3

Nebo Overthrust, Southern Wasatch Mountains, Utah ...... B. Allen Black 55

Paleoecologic implications of Strontium, Calcium, and Magnesium in Jurassic rocks near Thistle, Utah .... Button W. Bordine 91

Paleoecology of the Twin Creek Limestone In the Thistle, Utah area ...... Ladell R. Bullock 121

Geolo of the Stockton stock and related intmsives, &1e County, Utah ...... John L. Lufkin 149

Stratigraphy and rifera of Ordovician rocks near Columbia Iceads, Jasper National Park, Alberta, Canada ...... J. Keith Rigby 165

Lower Ordovician conodonts and other microfossils from the Columbia Icefields Section, Alberta, Canada ...... R. L. Ethington and D. L. Clark 185

Publications and maps of the Geology Department ...... 207 Brigham Young University Geology Studies

Volume 12 - December 1965

Contents

Thrusting in the Southern Wasatch Mountains, Utah ...... Michael J. Brady 3

Nebo Overthrust, Southern Wasatch Mountains, Utah ...... B. Allen Black 55

Paleoecologic irriplications of Strontium, Calcium, and Magnesium in Jurassic rocks near Thistle, Utah .... Burton W. Bordine 91

Paleoecology of the Twin Creek Limestone in the Thistle, Utah area ...... Ladell R. Bullock 121

Geology of the Stockton stock and related intrusives, Tooele County, Utah ...... John L. Lufkin 149

Stratigraphy and porifera of Ordovician rocks near Columbia Icefields, Jasper National Park, Alberta, . . Canada ...... J. Kelth Rlgby 165

Lower Ordovician conodonts and other microfossils from the Columbia Icefields Section, Alberta, Canada ...... R. L. Ethington and D. L. Clark 185

Publications and maps of the Geology Department ...... 207 A publication of the Department of Geology Brlgham Young University Provo, Utah 84601

Ed~tor J. Keith Rigby

Editorial Staff Lehi F. Hintze Myron G. Best

Brzgham Your~gUniuerszty Geology Studres is published annually by the Department. Geology Studies consists of graduate student and staff research in the Department and occasional papers from other contributors, and is the successor to BYU Research Studies, Geology Serier, published in separate numbers from 1954 to 1960.

Distributed December 31, 1965

Prrce $4.00 Thrusting in the Southern Wasatch Mountains, Utah*

MICHAELJ. BRADY Murarhon 011 Co., Ljrrleton, Colorudo

~ss~Il~c~.-Laramldedeformation occurred in at least two separate pulses The first and least extensive was the result of compressional forces predominantly toward S 21"E. Later major Laramide structures were formed by forces towards approximately N 7OoE. and were superimposed upon structures formed by southeastward compressional forces in the Southern Wasatch area. Comparison of stratigraphic sections at Santaquin Canyon in the Southern Wasatch Mounta~nswlth stratigraphic sections at Long Ridge and the East T~ntlcMountains to the west shows little differences except progressive eastward th~nnlng, lnd~catlng that they are ln close proximity to the relative posltlons in which they were deposited. No evidence was found indicating major horizontal displacements having taken place between these localities. New mapping of the Santaqu~nOverthrust suggests that all three of these sectlons are in the upper plate of a major thrust and were displaced a mlnlmum of seven miles in an easterly direction. The Santaquin Overthrust projects southward to the northern exposure of the Nebo Overthrust. Thus, it appears that the Santaquin thrust is a northern extension of the Nebo Overthrust. Directional properties associated w~ththe Red Point Thrust on the north end of Dry Mountain indicate displacement towards S.17'E. At the south end of West Moun- tain thrusting was probably toward N.45"-7O0E. Remapping of thrusts In Payson Canyon revealed the presence of a large fmster just east of Maple Dell Scout Camp where Oqulrrh Forlnat~onIn the upper plate has been eroded, exposing Cambrian and Miss~sslppianstrata of the lower plate.

CONTENTS

TEXT Humhug Formation ...... 10 page Great Blue Limestone ...... 31 Introduction ...... 4 Miss~ss~ppian-Pennsylvanian...... 32 Stratigraphy ...... 5 Mannlng Canyon Shale ...... 32 General Statement ...... 5 Pennsylvanian-Permian ...... 32 Precambr~an ...... 6 Oqulrrh Formation ...... 32 Farmington Canyon Complex .... 6 Permian ...... 3 3 B1g Cottonwood Formation ...... 7 Kirkman L~mestone ...... 33 Cambrian ...... 7 Cretaceous-Tertlary ...... 3 3 Tint~cQuartzite ...... 7 North Horn Formation ...... 33 Ophir Formation ...... 8 Tertiary ...... 33 Teutonic Limestone ...... 9 Flagstaff L~mestone ...... 33 Dagmar Limestone ...... 11 Colton Formation ...... 34 Herk~merLimestone ...... 12 Moroni Formation ...... 34 Bluebird Dolomite ...... 15 Summary and Conclusions ...... 34 Cole Canyon Dolomrte ...... 17 Structure ...... 36 Opex Format~on ...... 19 Pre-Laramide Deformation ...... 36 Ajax Dolomite ...... 2 1 Laram~deDeformation ...... 36 Devonlan ...... 22 Cenozo~cDeformation ...... 37 Victorla Formation ...... 22 Thrusts ...... 37 Pinyon Peak Limestone ...... 23 Santaquin Overthrust ...... 37 M~ss~ssippian...... 23 Payson Canyon Thrust ...... 41 Fltchvllle Formation ...... 24 Red Point Thrust ...... 43 Gardison Limestone ...... 26 White Lake Hills Thrust ...... 43 Deseret Limestone ...... 28 Keigley Quarries Thrust ...... 46 'A them submrted to the Faculty of the Department of Geology, Rrlgham Young Untverslty In partin1 fulfillment nf the requirements for the degree Macter of Srlenre MICHAEL J. BRADY

CONTENTS West Mountain Thrust ...... 46 3. Correlation Chart, Causes of Thrusting in the Gardison Limestone ...... 26 Southern Wasatch area ...... 46 4. Cornpos~te Section ...... 35 Dlrect~onof Thrust~ngin the 5. Geologic map and sections, Southern Wasatch area ...... 48 Santaquin Overthrust ...... 38, 39 Amount of Displacement of Thrust 6. Geologic map and sections, Sheets In the Southern Wasatch Payson Canyon Thrust ...... 42 area ...... 49 7. Geologic map and sections, References Cited ...... 52 Red Point Thrust ...... 44 8. Geologic map and section, ILLUSTRATIONS figure White Lake Hills Thrust ...... 45 1. Index Map ...... 6 9. Isopach and tectonic map, 2. Correlation Chart. Oquirrh Basin ...... 47 Herkimer Limestone ...... 13 10. Force diagram ...... 50

ACKNOWLEDGMENTS The writer gratefully acknowledges the criticisms and help given by Dr. L. F. Hintze who suggested this problem and to the National Science Founda- tion which provided financial assistance in order that it might be completed. Appreciation is extended to other faculty members of the geology department for their assistance. Thanks are in order for suggestions given bv B. Allen Black, who worked concurrently with the writer on a related problem in the Mt. Nebo-Salt Creek area. INTRODUCTION The flrst extensive stratigraphic and structural investigation in the Southern Wasatch Mountains was done by G. F. Loughlin (1913) who measured sections, collected fossils, and mapped the area along the Wasatch Range from Mt. Nebo to the north end of Dry Mountain. The first mention of thrusting in the area is found in this report when he states, "The principal structural features in the Santaquin-Mt. Nebo district are faults, including doubtful overthrusts of N.S. trend and a series of N.-S. and E.-W. block faults of the Basln Range type. The former are so poorly exposed, their course so nearly parallel to the N.-S. system of block faults, and, in some places, the rocks along them so free from severe crumpling or crushing, that the writer is not fully convinced of their overthrust character" (Loughlin, 1913, p. 448-449). A. J. Eardley (1933, 1934) mapped 230 square miles in an area extending from Salt Creek Canyon, on the south, to a mile north of Santaquin. Eardley recognized thrust faulting ln his mapping of the Nebo and Santa- quin "Overthrusts". He estimated approximately one mile of crustal shortening in the Mt. Nebo area as the result of thrusting. His only specific mention of direction of movement is concerned with the Santaquin "Overthrust" when he states, "A large-scale corrugated and slickensided surface indicates the direction of movement to be N.75"W." (Eardley, 1934, p. 383). It is not clear whether he interpreted movement towards the northwest or southeast. R. E. Metter (19<5) has done the most recent comprehensive report of this area in which he mapped the portion of the Wasatch Mountains located between Spanish Fork Canyon and Santaquin Canyon. Metter made minor revisions to Eardley's mapping of the Santaquin "Overthrust". He also mapped SOUTHERN WASATCH MOUNTAIN THRUSTING 5 thrustlng along the east s~deof Dry Mountaln and In the v~cin~tyof Payson Canyon. Under the direction of H. J. Bissell at Brlgham Young Universrty, J. H. Elison (1952), S. F. Schlinder (1752), J. W Swanson (1952), and B 0. White (1953) mapped thrusts at the south end of West Mountam while R S. Brown (1952) and D. J. Peterson (1956) have studied thrust faults In the Payson Canyon area. L. F. Hintze (1762) compiled a geologlc and topograph~c map of the Southern Wasatch Mountalns and vicinity. Durlng compilation of this map confus~on concerning the nature, amount, and d~rection of displacement of thrust sheets in the Southern Wasatch Mountalns came about as the result of discrepanc~esin the interpretations of prevlous investigators. Thus, it was Hlntze who suggested th~sproblem to the wr~ter. Appreciation is extended to these earher writers who, although havlng minor differences rn their work, contr~buted greatly to knowledge of the geology In the Southern Wasatch area and prov~deda foundat~onupon wh~ch much Information in this report is based. The purpose of this report IS to clarify relatr~nsh~pswhlch are thc result of thrust faultlng at Dry, Loafer, and West Mountains. A comparlson of stratigraphic sections in the East Tlntrc Mounta~ns,the north end of Long R~dge,and In Santaquin Canyon IS used in an attempt to approximate relative drstance of thrusting at these localit~es. Sect~ons on Long Rldge and In Santaquin Canyon were remeasured and used w~ththe sectlon measured by H. T Morris and T. S Lover~ng (1961) ~n the East

Tintic Mountains for this comDarlson1 To a~dIn determining the amount and nature of thrustlng a structural study of the writer included remapping, on photo enlargements, the area at the mouth of Santaqurn Canyon. Thrusting in West, Dry. and Loafer Moun- tains was re-examrned, especially where tonflrcts were apparent in the works ot previous workers. An examination and analys~sof drag folds, fracture patterns, and sl~cken- sldes, too small to map has been made to aid in f~nd~ngthc d~rect~onof displacement of thrust sheets. The part of the Southern Wasatch Mountalns studled In thls report IS located In central Utah in the vicinity of Payson and Santaquin (Text-f~g.1) and Ires w~thinthe reglon bounded by parallels 39O50' and 40O05' North Lat~tude,and mer~dians 11 1'40' and 11 1'50' West Longitude. A reg~onal synthesis consider~ngsome areas not included within these boundar~cs has also been analyzed STRATIGRAPHY General Statement Stratigraphy is crltical because a detalled comparlson of certaln strat~graphrc sections IS used to a~dIn estimat~ngthe relat~vtamount of d~splacement of thrust sheets. An unconform~t~places Lower Mississipplan strata In contact w~thUpper Cambr~anbeds throughout most of the Southern Wasatch reglon. Precambr~anand basal Cambrian unlts are clast~cin nature while the remainder of the Cambrian and the Mississippian strata are predominantly alternating clast~cand carbonate I~thologles. Mesozo~c and Cenozo~c formations ?re limited to clastics and volcanics. 6 MICHAEL J. BRADY

TEXT-FIGURE1.-Index map of geologic maps and studied areas.

Cambrian and Mississippian strata are of primary interest due to the availability of measurable sections of these units in the East Tintic Mountains, the north end of Long Ridge, and in Santaquin Canyon.

PRECAMBRIAN Farmington Canyon Complex The Farmington Canyon Complex is composed of the oldest rocks exposed in the Southern Wasatch Mountains. These rocks consist of schist, gneiss, pegmatite, and granite. They are exposed for about two miles along the western slope of Dry Mountain, extending from the north side of Santaquin SOUTHERN WASATCH MOUNTAIN THRUSTING 7

Canyon northward to the place where they become covered by recent sediments. Big Cottonwood Formation The Big Cottonwood Formation is a sequence of shales, quartzites, and phyllites exposed on the north side of Santaquin Canyon and on the southwest face of Dry Mountain. These beds are overlain unconformably by the Tintic Quartzite (Middle Cambrian) and rest on the basal Farmington Can- yon Complex. Thickness of the Big Cottonwood Formation on Dry Mountain ranges from approximately 1230 feet at the south end (Metter, 1955) to 373 feet at the north end (Demars, 1956). This variation in thickness resulted from erosion of upper beds of,the Big Cottonwood Formation prior to deposition of the Tintic Quartzite (Middle Cambrian) which rests upon the formation with angular discordance. CAMBRIAN Cambrian rocks crop out along the Southern Wasatch Front in a belt extending from the extreme north end of Dry Mountain southward to northeast of Mona. Termination of this belt, both north and south, is the result of normal faulting of the Wasatch fault "zone". Cambrian strata are also exposed, within a fenster, on the east side of Payson Canyon. Additional exposures are found at the south end of West Mountain, in the vicinity of the Keigley Quarries. with the exception of the basal Cambrian Tintic Quartzite and the Ophir Formation, Cambrian sections were measured by the writer in the Little Valley area of Long Ridge, and in Santaquin Canyon, to be used with the section measured in the East Tintic Mountains (Morris and Lovering, 1961) for a regional stratigraphic comparison. The Cambrian sequence of this area is similar to much of the Cambrian Cordilleran miogeosynclinal strata of the western United States. The basal Cambrian is typified by a sandstone or quartzite unit followed by a shale unit which in turn is overlain by a carbonate sequence. Terminology used in the East Tintic Mountains by Morris and Lovering (1961) was employed in distinguishing formational units of this report. Migliaccio (i958) has described several trilobite specimens from-the Ophir Shale in the West Mountain area. No identifiable fossils have been found in the Cambrian at Long Ridge or in Santaquin Canyon. Thus, Cambrian formations in this report were correlated on the bas~sof lithologic similarity and stratigraphic position. Tintic Quartzite The Tintic Quartzite was originally defined by G. 0. Smith (1900) as the sequence of quartzite and slate below the Middle Cambrian limestone in the Tintic mining district. The name was later restricted to the massive quartzites below the overlying Ophir shale by G. F. Loughlin (1919). Age of the Tintic Quartzite is uncertain because it has yielded no diagnostic fossils. The oldest known fauna in north central Utah is found in the Medial Cambrian Ophir Formation. The major portion of the Tintic Quartzite is most likely also Medial Cambrian. 8 MICHAEL J. BRADY

The most extensive exposure of Tintic Quartzite is located on the west slope of Dry Mountain where it is easily recognized by its resistant, massive, orange-brown ledges. Other small outcrops are found on the east side of Payson Canyon and just north of the Keigley Quarries on the south end of West Mountain. Lzthology and Thickness The Tintic Quartzite is fairly uniform in lithology being composed pri- marily of white, pink, orange-brown, fine to medium grained quartzite comprised of clean subrounded to rounded quartz grains. Many of the beds contain limonite cement and are somewhat micaceous. In Santaquin Canyon, Long Ridge, and the East Tintic Mountains the formation becomes coarser towards the base where ~t is typified by conglomeratic units. Beds range from thin to massive with thicker strata found ln the middle of the formation. Many beds are distinctly cross-bedded. An amygdaloidal basalt flow has been recognized 980 feet from the base of the Tintic Quartzite in the East Tintic Mountains. This unit is present nearer the base of the formation in Long Ridge and Santaquin Canyon (Abbot, 1951). Due to incomplete exposures, stratigraphic sections of the Tintic Quartzite were not measured for comparison. Thickness ranges from 822 feet on Dry Mountain (Metter, '1955, p. 32) to 2517 feet in the East Tintic Mountains (Morris and Lovering, 1961, p. 16). Tintlc Quartzite rests with angular unconformity upon Precambrian Big Cottonwood Formation below; the upper contact with the Ophir Formation

Ophir Formation The Ophir Formation was named by B. S. Butler for shale overlying the Tintic Quartzite and underlying the Teutonic Limestone, from the mining town of Ophir in the Oquirrh Mountains. Faunas collected from several different locallties indicate that the Ophir Formation contains two medial-Medial Cambrian faunal zones (Morris and Lovering, 1961) . The Ophir Formation is poorly exposed throughout much of the area due to incompetence of the unit. Exposures can be seen along the west face of Dry Mountain, northward from the south side of Santaquin Canyon. The formation has been thinned in places along Dry Mountain because of bedding plane slippage, and in Santaquin Canyon it is entirely absent due to thrusting. On the east side of Payson Canyon, the Ophir is covered by float, but in the Keigley Quarry area good exposures are seen in the quarry and in scattered outcrops a short distance to the north. The Ophir represents a transition from clastic sedimentation of the basal Cambrian to the carbonate sedimentation typical of the Upper Cambrian. The lower boundary with the Tintic Quartzite is somewhat gradational and is drawn at the base of the lowest prominent shale unit. The upper contact is at the base of the first massive limestone ledge of the Teutonlc Limestone. Lithology and Thickness The Ophir Formation consists principally of dark green phyllitic shale with interbedded green-brown quartzite beds near the base and interbedded limestone in the middle and upper portions. In the East Tintic Mountains the Ophir SOUTHERN WASATCH MOUNTAIN THRUSTING 9 has been subdivided into three un~ts:lower shale member. m~ddlelimestone member, and the upper shale member. These three members can be distinguished in Long Ridge but are not apparent in the Santaquin Canyon area, although the trans~tionfrom clastics to carbonates can be noticed. Because of poor exposures and thinning due to beddlng plane slippage it was not feas~bleto make a reg~onal comparison of the Ophlr Formation. Thickness of the Ophir ranges from 400 feet in the East Tintic Mountains (Morris and Lovering, 1961, p. 19) to 177 feet on Dry Mountain (Metter, 1955, p. 42) with Intermediate thickness of 277 feet in Long Ridge (Muessig, 1951, p. 18). (See Text-fig. 4).

Teutonic Limestone The Teutonic L~mestonewas named by G. F. Loughlin (1919) from Teu- tonic Ridge, one mlle northwest of Eureka. Fossils which belong to the Bathyuriscus-Elrathinu zone of medial-Medial Cambrian age have been collected from the Teutonic at several different locallties (Hintze, 1962b, p. 12). Teutonic Limestone is exposed along the western face of Dry Mountain, northward from the south side of Santaquin Canyon to the vicinity of Red Point. Less conspicuous outcrops are located on the east side of Payson Canyon near Maple Dell Scout Camp, and at the south end of West Mountain in the vicinity of the Keigley Quarries. The lower contact with the Ophlr Formation is at the base of the lowest massive limestone unit. The upper contact is sharply defined at the base of the light gray, blocky weathering, laminated Dagmar Dolomite. Lithology and Thzrkness Santayuin Canyon.-The Teutonic Limestone in Santaquin Canyon is predominantly a medium to dark gray, thln to massive bedded limestone which exhibits mottled weathering surfaces typical of Cambrian carbonates of this area. Irregular reddish-brown argillaceous partings are especially abundant near the base. Oolitic structures are present in thin dolomite beds near the middle of the formation. The top of the formation is marked by a medium bedded dolomite containing sparsely distributed "twiggy bodies", similar to those of the Bluebird Dolomite. Thickness of the Teutonic on the south side of Santaquin Canyon is 322.5 feet. Long Ridge (Little Valley).--In the Little Valley area the Teutonic is composed principally of limestone similar to that of Santaquin Canyon. Argillaceous partings are abundant throughout the unit, ranging from reddish brown at the base to light gray-brown towards the top. Thin, flat-pebble conglomerate beds and oolit~cstructures are common in the lower part of the format~on.The middle of the unit is characterized by a dolomite sequence 67 feet thick containing scattered "twiggy bodies". The top of the formation is a limestone unit which becomes slightly dolomitic near the contact with the Dagmar. The total thickness of the Teutonic Limestone measured in the Little Val- ley area is 370.5 feet. East Tintic Mountains.-In the East Tintic Mountains, the Teutonic Limestone is dominantly a medium-bedded light to dark gray limestone with irregular MICHAEL J. BRADY

r~bbon-likebands of arg~llaceousmaterlal. Oolitic and pisol~ticstructures are commonly found in beds which show cross-bedding near the middle of the unit. The top of the unit is composed of slightly laminated, abundantly oolitic thin bedded limestone. Th~cknessof the Teutonic as measured by Morris and Lovering (1961, p. 26-27) IS 400 feet.

Strat~graphlcsect~on of Teutonic L~mestone measured on the south srde of Santaquin Canyon near the center of Sec 30, T. 10 S., R. 2 E., by M. J. Brady, 1964.

Conformable contact wlth Dagmar Dolomrte. 5 Dolomite. dark gray at the base grad~ngInto med~umgray towards the top, weathers med~um gray, rned~uni crystall~ne, medrum bedded, a few "twiggy bodies" are locally present. 25.5 4. Lrmestone; dark to lnedlum gray, weathers to rnedium gray, med~um crystalllne, thln to medium bedded, ool~ticstructures are present In some beds, irregular I~ghtgray arg~llaceouspartings are common, locally abundant calcite vugs. 67.0 3 Dolomrte; niedium gray, f~neto med~umcrystall~ne, oolitrc structures present, medrum bedded, irregular bedding surfaces, a few l~ght gray argillaceous partings can be seen towards the top of the un~t. 5.0 2. L~mestone;dark gray, med~umgray when weathered, med~umcrystall~ne, med~umto th~ckbedded, ~rregularbedd~ng surfaces, abundant l~ght gray arg~llaceous partrngs, mottled or pocked appearance. 107.0 1. Limestone; medium to dark gray, weathers medium-dark gray, fine to med~umcrystall~ne, thick to massive bedded, mottled appearance, abundant redd~shbrown ~rregularargrllaceous part~ngs,rock has a tendency to spl~talong the arg~llaceaus rnater~al. 123.0

Total 327.5

Conformable contact w~thOph~r Format~on. Stratrgraphic section of Teutonrc L~mestonemeasured in the Little Valley area of Long R~dge,in the SWS Sec. 17, T. 10 S., R. 1 E., by M. J. Brady, 1964. Teuton~cLimestone Contact conformable with Dagrnar Dolomite. h Limestone; med~umgray, weathers to med~umgray brown, med~umto thick bedded, f~neto med~umcrystalline, light gray brown argillaceous partings, mottled appearance, unit becomes more dolom~t~c towards the top, more dolomitic beds appear grainy or sugary and are sl~ghtlylaminated near contact w~ththe Dagmar Dolom~te 107.0 5. Dolomite, dark-med~umgray, weathers to medium gray, med~umbedded, medium crystall~ne, weathered surface IS less mottled than the l~niestonebelow, darker unlts more mottled than the lrght beds, argrllaceous materlal varles from a light gray to l~ghttan, oolites are abundant with a few "twrggy bod~es" present in some beds. 67.0 4. L~mestone,medium-blue gray, weathers light-blue gray, f~neto medium crystall~ne, thin to medium bedded, unrt has mottled r~bbon-lrke appearance due to argillaceous partrngs, srgillaceous material becomes less abundant and more lrght gray towards the top of the unit, near the base are three 6" to I' beds composed of intraforma- t~onalconglomerates. 152.0 3 Limestone; bluish gray, abundant gray~shorange arg~llaceousmater~al. niedium crystalline, some oolit~cstructures. 6.0 SOUTHERN WASATCH MOUNTAIN THRUSTING 11

2. Limestone; intraforniational conglomerate consist~ngof flat shaped I~mestone clasts. 0 5 1. Llmestone; med~umblue gray, weathers light blue gray, medium crystal- Ilne, masslve beddlng, very mottled appearance, llght tan to gray argillaceous material is abundant, materlal forms partings which resemble crinkley bedding, oolitic mater~al 1s sparsely dlstrlbuted throughout. masslve cliff forming unlt. 38 0

Total 370.5 Conformable contact with Ophlr Formation.

Dagmar Limestone The Dagmar Llmestone, more commonly known as the Dagmar Dolomlte, was named by G. F. Loughlin, (1919) for the thin yellow~shto graylsh-white dolomite underlying the Herkimer Llmestone and overlying the Teutonic Lime- stone, near the Dagmar Mlne in the Tintrc district. No fossils have been reported from the Dagmar but ~tsstratrgraphlc posr- tlon between the medial-Medial Cambrian Teutonlc Limestone and the Medlal Cambrlan Herklmer Lrmestone enable its age to be fairly accurately determrned. Because of extreme contrasts In color with the formations above and below, outcrops of the Dagmar Dolomrte are easily distinguished along the western face of Dry Mountam, from the south side of Santaquin Canyon northward to Red Pornt, northeast of Payson. Exposures are also present on the east srde of Payson Canyon, near Maple Dell Scout Camp, and at the south end of West Mountain but are not so prominent as those on Dry Mountaln because of the more subdued topography near West Mountarn. Contacts of the Dagmar appear to be sharp, from a distance, but when observed closely gradational lithologies are apparent. Boundarres with the Teutonic Limestone below and the Herk~merLimestone above are distinguished by the light gray, blocky weathering, laminated dolomlte, typlcal of the Dag- mar. Llrhology und Th~ckness Santayu/n Cat2yon.-The Dagmar Dolomite in the Santaquin Canyon area 1s a fine to medium crystall~ne, thrn to medium bedded, blocky weathering, finely laminated dolomite. The ash-whlte color to whlch the Dagmar weathers is the most easily observed dragnostrc characteristic. The thickness of the Dagmar Dolomite IS 36 feet in Santaquln Canyon.

Long Rzdge (L~ttleValley).-The Dagmar in the Lrttle Valley area IS almost identical to that of Santaquin Canyon. Contacts wrth the Teutonrc and Herkl- mer limestones are more gradational than those of Santaquln Canyon. Thickness of the Dagmar Dolomlte is 51.5 feet in the Lrttle Valley area of Long Ridge. East Tnztic ~Mountat~zs.-The Dagmar is predominantly a thrn bedded, f~nely crystalline, lammated dolomite that weathers wlth a blocky fracture and characteristic creamy wh~tecolor. Near rts contact w~ththe Teutonic Lrmestone the Dagmar is comprised of dolomlte Interbedded with several thln layers of silt- stone. A shale unrt three feet thick is located ten feet from the top of the formation. Thrckness of the Dagmar In the East Trntic Mounta~nsIS 65.5 feet. 12 MICHAEL J. BRADY

Stratigraphic section of the Dagmar Dolomite measured on the south side of Santaquin Canyon, in the SW%, of Sec 30, T. 10 E., R. 2 E., by M. J. Brady, 1964. Dagmar Dolomite Conformable contact with Herkimer Limestone. 8. Dolomite; medium to dark gray, weathers light gray, micritic, laminated, medium bedded, blocky weathering. 6.0 7. Dolomite; medium gray, weathers light gray to cream, finely crystalline, wavy laminations, medium bedded, blocky weathering. 2.5 6. Dolomite; medium to light gray, weathers to very light gray, finely crystalline, indistinct laminations, thin to medium bedded, blocky weathering. 7.5 5. Dolomite; medium to dark gray, weathers to medium gray, fine to medium crystalline, laminated, medium bedded, blocky weathering. 12.0 4. Dolomite; dark gray, weathers to medium-light gray, medium crystalline, lacking laminations, medium bedded, blocky weathering. 2.0 3. Dolomite (limy); dark-medium gray, weathers to tnrdium gray, micritic to finely crystalline, laminated, medium bedded, blocky weathering. 2.5 2. Dolomite; medium gray, weathers to medium-light gray, finely crystalline, lacking laminations, thin bedded, blocky weathering. 1.5 1. Dolomite; medium to dark gray with tints of pink, weathers light gray fine to medium crystalline, laminated. thin to medium bedded, blocky weathering. 2.0 --- Total 36 Conformable contact with Teutonic Limestone. Stratigraphic section of Dagmar Dolomite measured in the Little Valley area of Long Ridge, in SW%, Sec. 17, T. 10 S., R. 1 E., by M. J. Brady, 1964. Dagmar Dolomite Conformable contact with Herkimer Limestone. 4. Dolomite; interbedded medium gray and light gray, weathers medium gray to cream color, micritic to medium crystalline, distinct to indistinct laminations, thin to medium bedded, some beds are slightly limy approximately one-fourth of this unit is covered with float blocky weathering. 23.5 3. Dolomite; light-medium gray, weathers to cream color with a brownish tint, micritic to finely crystalline, wavy lam~nations,medium bedded, blocky weathering. 2. Dolomite; medium gray with a pink tint, weathers light gray, laminated thin to medium bedded, blocky weathering. 9.5 1. Dolomite; medium gray, weathers to medium light gray. Cinely crystalline, laminated, medium bedded, slightly limy, blocky weathering. 4.5 --- Total 51.5 Conformable contac-t with Teutonic Limestone.

Herkimer Limestone The Herkimer Limestone was named by W. Lindgren and G. F. Loughlin (1919) for the mottled shaly limestone overlying the Dagmar and underlying the Bluebird Dolomite, expcsed near the Herkimer shaft, east of Quartzite Ridge in the Tintic mining district. Only a few unidentifiable fossils have been reported from the Herkimer although it is surely of Medial Cambrian age as determined by collections from adjacent Cambrian formations (Hintze, 1962, p. 12-13). SOUTHERN WASATCH MOUNTAIN THRUSTING 13

Extensive outcrops of Herkimer are exposed on the western face of Dry Mountain, northward from the south side of Santaquin Canyon to east of Payson. The Herkimer so resembles the Teutonic that the two would be difficult to distinguish were it not for the easily identified Dagmar Dolomite separating the two. Other outcrops in the area of this report are found on the east side of Payson Canyon in the vicinity of Maple Dell Scout Camp, and at the south end of West Mountain in the Keigley Quarries and in low hills to the north. The lower contact of the Herkimer with the Dagnlar appears quite abrupt but is somewhat gradational if observed closely. The upper boundary with the Bluebird Dolomite is gradational and the contact is arbitrarily placed at the point where argillaceous partings of the Herkimer become indistinct. Lithology and Thirkners Santayuitz Catzyo)z.-The Herkimer Limestone is principally a medium to dark gray, medium to massive bedded, fine to medium crystalline 'limestone with reddish-brown argillaceous partings throughout. The entire unit exhibits mottled weathered surfaces typical of the Cambrian carbonates. Dolomite units are present 27 feet above the base and at the top of the formation. Oolitic structures and conglomeratic layers are present in massive beds found near the middle of the unit. The Herkimer measured 285.0 feet thick on the south side of Santaquin Canyon. Lo~gRidge (Little Valley).-The major portion of exposed Herkimer Lime- stone in Little Valley is a dolomite similar to the dolomite of Santaquin Can- yon. These dolomites contain sparsely scattered "twiggy bodies" and oolitic structures. There is no basal limestone in the Herkimer of Little Valley such as was present in Santaquin Canyon. The top of the formation is a medium

East Tintic Santrquin Canyon Mountains ,- 20 mi 5 mi -

/ Brady (1964)

Thickness 427.5 feet Morris & Lovering (1961)

TEXT-FIGURE2.-Diagrammatic comparison of the Herkimer Limestone between the East Tintic Mountains, Long Ridge, and Santaquin Canyon. Numbers correspond to units in the accompanying- measured sections. 14 MICHAEL J. BRAD>-

bedded limestone unit containing abundant yellow-green argillaceous material which gives the strata a wavy appearance. Thickness measured in the Little Valley area is 321 feet. East P'itztic Moun/az,zs.-The base of the Herkimer of the East Tintic Moun- tains contains oolitic and pisolitic structures, flat pebble conglomerate, and clastic cross-bedded limestone which has abundant light weathering argillaceous partings. A middle shale member of the Herkimer is composed of fissile green shale containing flat pebble conglomerates. The upper part of the formation is medium bedded limestone containing abundant yellowish to pink argillaceous partings with some oolitic and conglomeratic layers. Thickness of Herkimer Limestone in the East Tintic Mountains is 427.5 feet (Morris and Lovering, 1961, p. 33). A diagrammatic representation of the Herkimer Limestone located in the three areas discussed above can be seen in Text-figure 2.

Stratigraphic section of Herkimer Limestone measured on the south side of Santaquin Canyon, NES, Sec. 30, T. 10 S., R. 2 E., by M. J. Brady, 1964. Herkimer Limestone Conformable contact with Bluebird Dolomite. 6. Dolomite; medium gray, weathers light-medium gray, fine to medium crystalline, abundant light gray argillaceous partings which weather tan, unit is slightly lime at base becoming more dolomitic towards the to^. 14.0 3. Limestone; medium gray, weathers light-medium gray, micritic to finely crystalline, thin to medium bedded, irregular light gray weathering argillaceous partings, some oolitic and conglomeratic beds near base which range in thickness from one to six inches, unit has mottled appearance. 43.0 4. Limestone (shaly); medium gray, weathers light gray, ~nicritic, thin bedded, unit is somewhat fissile. 13.0 3. Limestone; dark to medium gray, weathers medium gray, micritic to finely crystalline, medium to massive bedded, light gray to tan argillaceous partings which weather to a reddish-brown are common, oolitic material is present in beds ranging from 2" to 8" scattered throughout the unit. 120.0 2. Dolomite; medium to dark gray-brown, weathers medium gray-brown, fine to medium crystalline, thick to massive bedded, abundant light gray argillaceous partings, twiggy bodies are locally abundant, calcite vugs are common. 68.0 1. Limestone; dark gray-brown, weathers medium gray, fine to medium crystalline, irregular gray argillaceous partings, medium to massive bedded, unit has mottled appearance on practically all weathered surfaces. 27.0

Total 285.0 Contact conformable with Dagmar Dolomite. Stratigraphic section of Herkimer Limestone measured in the Little Valley area of Long Ridge, NE% Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Herkimer Limestone Conformable contact with Bluebird Dolomite. 7. Limestone; medium dark gray, weathers medium blue gray, medium crystalline, medium bedded, contains abundant yellow brown argillaceous material which gives the unit a ribbon like appearance, SOUTHERN WASATCH MOUNTAIN THRUSTING 15

mottled weathering habit, contact with Bluebird Dolomite is covered. 105.0 6. Zone of float cover. Float consists of limestone fragments from above. 55.0 5. Dolomite; medium gray, weather medium gray, medium crystalline, medium bedded, mottled weathering appearance which is not as uniform as in other units, abundant red argillaceous mattrial. 87.0 4. Dolomite; medium dark gray, weathers brown-gray, medium crystalline, medium bedded, grainy texture, contains some red argillaceous material, sparsely scattered "twiggy bodies" appear toward the top of the unit, three thin beds containing abundant oolite are present near the top. 37.0 3. Dolomite; dark medium gray, weathers medium gray, medium crystalline, grainy appearance, medium bedded, slightly lime, some red argillaceous material. 12.0 2. Dolomite; interbedded light-medium and medium gray beds, some lithology as unit one except no "twiggy bodies" are present. 12.0 1. Dolomite; dark medium gray, weathers medium gray, medium crystalline, grainy appearance, medium bedded, mottled weathering appearance, sparsely distributed "twiggy bodies". 13.0 Total 321.0 Contact conformable with Dagmar Dolomite.

Bluebird Dolomite The Bluebird Dolomite was named by G. F. Loughlin (1919) for Blue- bird Spur in the Tintic district where the formation crops out as dark, bluish- gray, fine grained dolomite. The only fossils reported from the Bluebird Dolomite were located within ten feet of the top of the formation on the south slope of Eureka Ridge and were identified as trilobites of Medial Cambrian age (Morris and Lovering, 1961). Exposures of the Bluebird in the area of this report are located on the western slope of Dry Mountain, northward from the south side of Santaquin Canyon to east of Payson, on the east side of Payson Canyon across from Maple Dell Scout Camp, and at the south end of West Mountain in the vicinity of the Keigley Quarries. The lower contact of the Bluebird Dolomite with the Herkimer Limestone is graditima~and sometimes difficult to distinguish. This lower contact is established on the basis of the abundance of "twiggy bodies" which are short white dolomite rods characteristic of the Bluebird. These "twiggy bodies" continue into the basal Cole Canyon Dolomite above so the upper boundary is placed at the base of the first creamy white, laminated unit of Cole Canyon.

Lithology arzd Thicknesr Sa~ztaquinCa)zyon.-Bluebird Dolomite of the Santaquin area is a medium to massive bedded, dark gray, fine to medium crystalline dolomite. The lower contact with the Herkimer Limestone is difficult to discern and is somewhat arbitrary due to the lack of abundant "twiggy bodies" in the Bluebird of this vicinity. The top unit of the formation is a massive cliff-forming dolomite with extremely mottled weathering surfaces. A Bluebird Dolomite section 184 feet thick was measured on the south side of Santaquin Canyon. 16 MICHAEL J. BRADY

Long Ridge (Little Valley).-Bluebird Dolomite in the Little Valley area is very similar to that of Santaquin Canyon with exception of a greater abundance of "twiggy bodies", enabling the formation to be identified more easily. The unit is medium bedded and does not form massive cliffs like those in Santa- quin Canyon. A section of Bluebird Dolomite 182 feet thick was measured in the Little Valley area. East Tintic Mountaz~zr.-The Bluebird in the East Tintic Mountains is composed entirely of dolomite similar to that of Santaquin Canyon and Little Valley. "Twiggy bodies" are more abundant throughout the formation and the base is characterized by oolitic and conglomeratic layers, some of which are indistinctly cross-bedded. Thickness of the Bluebird Dolomite in the East Tintic Mountains is 204.5 feet (Morris and Lovering, 1961, p. 37).

Stratigraphic section of Bluebird Dolomite measured on the south side of Santaquin Canyon NE 1/4 Sec. 30, T. 10 S., R. 2 E., by M. J. Brady, 1964. Bluebird Dolomite Contact conformable with Cole Canvon Dolomite. 2. Dolomite; dark gray, weathers medium dark gray, micritic to finely crystalline, massive bedded, scattered "twiggy bodies" are present throughout the unit, mottled weathering surface, prominent cliff former with gray weathering patches apparent. 81.0 1. Dolomite; dark-medium gray, weathers medium gray, fine to medium crystalline, medium to thick bedded, contact with Herkimer is gradational and the argillaceous partings gradually disappear towards the middle of the unit, "twiggy bodies" can be seen in some localized areas, slightly mottled appearance, some beds contain small amounts of lime near the base of the unit. 103.0

Total 184.0

Contact with Herkimcr Limestone is conformable. Stratigraphic section of Bluebird Dolomite measured in the Little Valley area of Long Ridge, NE 1/4 Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964.

Bluebird Dolomite Contact conformable with Cole Canyon Dolomite. 8. Dolomite; medium gray, weathers light-medium gray, medium crystalline, medium bedded, "twiggy bodies" are absent, beds are somewhat banded. 10.0 7. Dolomite; medium gray, weathers dark-medium gray. medium crystalline, medium bedded, massive weathering habit, weathered surface is slightly mottled. "twiggy bodies" become more abundant towards top of unit. 21.0 6. Dolomite; medium crystalline, weathers light-medium gray, medium crystalline, absence of "twiggy bodies". 16.0 5. Dolomite; dark gray, weathers dark gray-brown, medium to coarsely crystalline. massive to medium bedded, abundant "twiggy btdies." 26.0 4. Dolomite; medium gray, weathers dark medium gray, medium crystalline, medium to massive bedding, sparse "twiggy bodies", weathered surface slightly mottled, some beds have a grainy texture. 74.0 3. Dolomite: medium gray-brown. weathers medium gray, oolitic bed. 1 .0 SOUTHERN WASATCH MOUNTAIN THRUSTING 17

2. Dolomite; medium gray, weathers somber gray brown, medium crystalline. grainy texture, sparse "twiggy bodies". 4.0 I. Contact with Herkilner is covered with float. 30.0

Total 182.0 Contact with Herkimer Limestone is conformable.

Colt Canyon Dolomite The Cole Canyon Dolomite was named by G. F. Loughlin (1919) for the dolomite overlying the Bluebird Dolomite and underlying the Opex Dolomite in Cole Canyon at the Tintic mining district. Eldoradia cf. E. prospectei~.ris (Walcott) has been collected from the upper part of the Cole Canyon in different localities and is characteristic of rocks of late-Medial Cambrian age. Thus, the Medial.Late Cambrian boundary is probably near the Opex-Cole Canyon contact (Hintze, 1962, p. 13). Outcrops of Cole Canyon are easily distinguished in Santaquin Canyon and along the western face of Dry Mountain because of the formation's alternating light and dark gray dolomites. Less conspicuous exposures are located in small fault blocks on the east side of Payson Canyon near Maple Dell Scout Camp, and at the south end of West Mountain near the Keigley Quarries. The lower contact of the Cole Canyon is drawn at the base of the first white weathering, laminated, dolomite unit above the Herkimer Limestone. The upper boundary, which is gradational and difficult to distinguish at Long Ridge and Santaquin Canyon, is placed at the base of the first sucrosic dolomite unit containing oolitic structures. The contact in the East Tintic Moun- tains is at the base of the first limestone of the Opex Formation. Lirholoav and Thicknet.r - 2 Sai2tayuin Ca~zyoiz.-In Santaquin Canyon the Cole Canyon Dolomite comprises a sequence of interbedded light and dark gray dolomites which become slightly limy near the middle of the unit. Light-weathering dolomite beds are almost identical to the "Dagmar type" strata seen lower in the section. Darker beds range from medium to dark gray and contain scattered "twiggy bodies", resembling dolomite of the Bluebird of this area. This formation is one of the less resistant units of the Cambrian carbonate sequence in Santaquin Canyon, forming a steep slope above the prominent Bluebird Dolomite ledge. Thickness of the section measured in Santaquin Canyon is 461 feet. Long Ridge (Little Valley).-The Cole Canyon in this area is similar to that of Santaquin Canyon. The lower 15 feet of the unit is characterized by tan chert occuring as lenses within "Dagmar type" dolomite beds. Darker beds contain abundant "twiggy bodies" and are very much like the Bluebird Dolo- mite strata of the Little Valley area. Thickness of the section measured in the Little Valley area is 436 feet. Ea~tTj~tic Mout2tai1zs.-The Cole Canyon is easily distinguished from other formations in the East Tintic district by its alternating light and dark strata, thinly laminated beds, and well-stratified appearance. Beds that weather creamy white to light gray are normally medium gray on fresh fracture; many are fine grained and finely banded and resemble the Dagmar Dolomite (Morris and Lovering, 1961, p. 40). It differs from the Cole Canyon of Santaquin Canyon and Little Valley in that the base and upper part of the 18 MICHAEL J. BRADY formation contain several intraformational conglomerate and chert layers while some units in the middle display indistinct cross-bedding. Thickness of the Cole Canyon in the East Tintic Mountains is 852.5 feet (Morris and Lovering, 1961, p. 42).

Stratigraphic section of Cole Canyon Dolomite measured on the south side of Santaquin Canyon, SW. I/s Sec. 29, T. 10 S., R. 2 E., by M. J. Brady, 1964. Cole Canyon Dolomite Conformable contact with Opex Formation. 5. Dolomite; alternating beds of medium-dark gray and light gray with pink tints, weather medium gray to cream, micritic to medium crystalline, medium bedded, many of the darker beds contain some "twiggy bodies" similar to the Bluebird Dolomite, the dark beds appear more mottled than the light beds, the light beds are laminated and appear identical to the Dagmar dolomite beds. 180.0 4. Dolomite (limy); medium gray, weathers light medium gray, fine to medium crystalline, medium bedded, mottled weathering surfaces. 45.0 3. Dolomite; light-medium gray, weathers light gray, medium crystalline, medium bedded, some beds are thinly laminated. 27.0 2. Dolomite; medium gray, weathers light-medium gray, fine to medium crystalline, a few thin beds scattered throughout but predominantly medium bedded, mottled weathering surface, some indistinct irregular argillaceous partings. 32.0 1. Dolomite; alternating beds of medium-dark gray and light gray with a pink tint, weathers medium gray to cream, micritic to medium crystalline, medium bedded, many of the darker beds contain some "twiggy bodies" similar to the Bluebird Dolomite, the dark beds appear somewhat more mottled than the light beds, irregular laminations are present within the light beds. -177.0 Total 461.0 Contact conformable with the Bluebird Dolomite.

Stratigraphic section of Cole Canyon Dolomite measured in the Little Valley area of Long Ridge, NW 1/4 Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Cole Canyon Dolomite Conformable contact with O~exFormation. 10. Dolomite; medium gray, weathers light medium gray, medium crystalline, medium bedded, mottled weathering habit, "twiggy bodies" present, some cream colored laminated beds are present, the contact is drawn at the top of the last cream colored laminated bed. 41.0 9. Dolomite; light medium gray, weathers light gray, medium to coarsely crystalline, medium bedded, some beds have a sugary texture. 46.0 8. Dolomite; medium gray, weathers medium gray, medium crystalline, medium bedded, mottled weathering surfaces, some beds are grainy, fairly abundant "twiggy bodies" dispersed throughout. 127.0 7. Dolomite; cream colored with a pink tint laminated dolomite. 6.0 6. Dolomite; medium blue-gray, weathers medium light gray, finely crystalline, medium bedded, very mottled weathering surface. 30.0 5. Zone of cover. 50.0 4. Dolomite; medium dark gray, weathers dark medium gray, medium crystalline, medium bedded, mottled weathering surface, abundant "twiggy bodies". 104.0 3. Dolomite; medium gray brown, weathers light gray to chalky white, SOUTHERN WASATCH MOUNTAIN THRUSTING 19 le finely crystalline, medium bedded, slightly mottled appearance, laminated. some chert lenses present. 2.0 2. Dolomite; medium dark gray, weathers dark medium gray-brown, It medium crystalline, medium bedded, mottled weathering surface with sparse "twiggy bodies". 15.0 1. Dolomite; medium gray brown, weathers to chalky white, medium n bedded, finely crystalline, very well laminated, some tan chert present. -15.0 Total 436.0 Contact conformable with Bluebird Dolomite.

Opex Formation The Opex Formation was named by G. F. Loughlin (1919) for the Opex mine in the Tintic Mining district, where a series of shaly limestones and dolomites is exposed. The only diagnostic fossils reported from the Opex are trilobites collected from the upper part of the formation which represent the Elwinla zone of medial-Late Cambrian age (Morris and Lovering, 1961, p. 46). Exposures of Opex are present along the western slope of Dry Mountain extending northward from the south side of Santaquin Canyon to Red Point, east of Payson. Other outcrops are located on the east side of Payson Canyon near Maple Dell Scout Camp, and at the south end of West Mountain in a belt extending two miles north of the Keigley Quarries. The lower boundary was placed at the base of the oolitic and conglomeratic unit above the Cole Canyon Dolomite in Santaquin Canyon and the Little Valley area of Long Ridge. In the East Tintic Mountains the lower contact is at the base of the first shaly limestone unit above the Cole Canyon Dolo- mite. In Santaquin Canyon the upper contact of the Opex with the Mississip- pian Fitchville Formation is unconformable and is placed at the base of the first cherty, fossiliferous unit. The upper boundary in the Little Valley area was drawn at the base of the first abundantly cherty, finely crystalline dolomite of the Ajax. The top of a sequence of shaly limestones marks the upper boundary in the East Tintic Mountains. Lithology and Thickness Santaquirz Canyon.-In Santaquin Canyon the Opex is lithologically quite different from the Opex of the East Tintic Mountains. The formation in this area is comprised entirely of dolomite with a few thin layers of oolitic and conelomeratic material at the base. The units are medium to massive bedded. (7 light to dark-medium gray, and several have a sucrosic texture. Thinning of the formation to the north is a result of an unconformity. Thickness of the section in Santaquin Canyon is 291 feet. Long Ridge (Little Valley).-The Opex of the Little Valley area is more like that found in Santaquin Canyon than in East Tintic Mountains. The unit is entirely dolomite with a few conglomeratic layers present at the base. Near the middle of the unit there is a 4.5 feet thick quartzite unit which weathers tan and displays well defined cross-bedding. Thickness of the Opex Formation measured in the Little Valley area is 195 feet. East Tintic Mountains.-Beds of limestone and shale comprise the bulk of the Opex Formation in the East Tintic Mountains with minor dolomite and sand- 20 MICHAEL J. BRADY

stone units near the top. Some of the limestone units contain oolitic and conglomeratic material and are interlayered with thin layers of dolomite, shale, and sandstone. Thickness of the Opex Formation in the East Tintic Mountains is 245 feet (Morris and Lovering, 1961, p. 45).

Stratigraphic section of Opex Dolomite measured on the south side of Santaquin Canyon, SW i/q Sec. 29, T. 10 S., R. 2 E., by M. J. Brady, 1964 Opex Dolomite Unconformable contact with Fitchville Formation. 6. Dolomite; medium to dark gray, weathers light gray, fine to medium crystalline, medium to massive bedded, sucrosic texture. 40.0 5. Dolomite; medium-light gray, weathers to light gray, thin to mediunl bedded, sucrosic texture. medium crystalline. 27.0 4. Dolomite; medium-light gray, weathers to light gray. thin to medium bedded, sucrosic texture, medium crystalline. 26.0 3. Dolomite; medium-dark gray to medium brownish gray, weathers medium gray, medium crystalline, mottled on weathered surfaces. 97.0 2. Dolomite; medium gray, weathers to medium-light gray, medi11111crystal- line, medium to thick bedded, mottled weathered surfaces, thin argillaceous partings common in middle of unit. 37.0 1. Dolomite; light blue-gray, weathers to light gray. fine to mediunl crystalline, medium to massive bedded, tan argillaceous material near top, intrafocmational conglomerate beds 6" thick 31 feet from top of unit, some very thin beds containing oolitic material near the base of the unit, sucrosic texture. 64.0

Total 291.0 Conformable contact with Cole Canyon Dolom~te.

Stratigraphic section of Opex Formation measured in the Little Valley area of Long Ridge, NW 1/9 Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Opex Dolomite Conformable contact with Ajax Formation. 6. Dolomite; medium gray, weathers to light buff-gray, medium crystalline, medium to massive bedded, slightly sucrosic texture, mottled weathered surface. 51.0 5. Dolomite; medium blue gray. weathers to light medium gray, medium grained, medium to massive bedded, grainy or arenaceous texture, some beds are medium crystalline and have sucrosic textures. 25.0 4. Dolomite; light gray, weathers to a light buff, medium crystalline or fine grained, abundant oolites present in middle of unit, mediuni to thin bedded. 17.0 3. Quartzite; light brown gray, weathers to tan, thin to medium bedded, fine grained, abundant cross bedding. 4.5 2. Dolomite; medium blue gray, weathers medium g.ay, fine grained, medium bedded, mottled weathering surface. 51.0 1. Dolomite; light medium gray, weathers to medium light gray, fine grained, medium to massive bedded, some beds have a sucrosic texture, mottled weathering surface, near its base the unit has two 6" beds which appear to be intraformational conglomerates. 47.0

Total 195.5 Canformable with Cole Canyon Dolomite. SOITTHERN WASATCH MOUNTAIN THRUSTING 2 1

Ajax Dolomite C.F. Loughlin (1919) named the Ajax Dolomite and defined its lithology from a series of steeply dipping dolomite beds near the Emerald mine of the Tintic district. Fossils collected from the Ajax indicate the formation is Late Cambrian age (Morris and Lovering, 1961, p. 50). The Ajax Dolomite was not found in the Southern Wasatch Mountains but it was present in the Little Valley area of Long Ridge.

L~rholog)rrnd Thrrkness Loizg Ridge (Little Valley).-The three members of the Ajax described in the Tintic district are also present and can be distinguished in the Little Valley area. The bottom and top members are primar~ly dolomite containing some chert and arg~llaceouspartings, and displaying indistinct cross-bedding. The middle dolomite member is distinguished by its finely crystalline texture, and creamy white weathering color. Thickness of the Ajax Dolomite in the Little Valley area is 304 feet. Ea~tT17ztic Mo~)ztaz~z~.-TheAjax in the East Tintic Mountains can be divided into three members: a dark mottled and cherty lower dolomite member, the massive light colored middle member, and the upper medium gray dolomite member. Chert and conglomeratic layers are distributed throughout the unit. Thickness of the Ajax Dolomite in the East Tintic Mountains is 560 feet (Morris and Lovering, 1961, p. 48-50).

Stratigraphic section of Ajax Dolomite measured in the Little Valley area of Long Ridge, NE '/4 Sec. 21, T. 10 S., R. 1 E., by M. J. Brady, 1964. Ajax Dolomite Contact unconfor~nable with Victoria Formation. Lipper Ajax Member: 5. Dolomite; light brownish gray, weathers to light gray, finely crystalline. medium to thick bedded, some arenaceous beds are present which show cross bedding, contact with the Victoria Formation is covered with alluvium. 65.0 4. Dolomite; medium gray, weathers to light gray, medium to coarsely crystalline, mottled weathering surfaces, characteristic sucrosic texture. 47.0 Middle Ajax Member: 3. Dolomite; light brownish gray, weathers to creamy white, micritic to finely crystalline, thick to massive bedded, bedding surfaces are irregular, weathered surfaces are mottled. creamy color makes this unit distinctive. 38.0 Lower Ajax Member: 2. Dolomite; medium gray, weathers to medium blue gray, fine to medium grained, some crossbedding is present, medium to thick bedded, mottled weathered surface. 55.0 1. Dolomite; light-medium gray, weathers to light gray, fine to medium crystalline, thin bedded, some argillaceous partings are present near the base, chert scattered throughout unit, slope forming unit. 99.0 Total 304.0 Contact conformable with Opex Formation. 22 MICHAEL J. BRAD\-

DEVONIAN Either Late Devonian erosion removed all of the Ordovician, Silurian, and Devonian units in the vicinity of Santaquin Canyon of the Southern Wasatch Range or this period of time was one in which no deposition occurred. The Pinyon Peak Limestone (Late Devonian and Early Mississippian age) is present on the south end of West Mountain, north of the Keigley Quarries, and rests unconformably upon Upper Cambrian strata. In the Little Valley area of Long Ridge the Pinyon Peak Limestone overlies the Late Devonian Victoria Forma- tion, which in turn rests unconformably on Upper Cambrian strata.

Victoria Formation The Victoria Formation was named and defined by G. F. Loughlin (1919) for the sequence of dolomites and quartzites located in the Tintic mining district in the area of Eureka Ridge. Although the Victoria Formation has yielded no identifiable fossils, it must be of Late Devonian age, because the top of the Bluebell Dolomite, which underlies it, and the lower part of the Pinyon Peak Limestone, which overlies it, have both yielded Late Devonian Fossils (Morris and Lovering, 1961, p. 73). The Victoria is not present in the Southern Wasatch Mountains, but was measured at the Little Valley area of Long Ridge.

Lithology and Thich,~ess Long Ridge (Little Valley).-The Victoria Formation of the Little Valley area is a non-resistant slope forming unit which is mainly covered by float. Quartzites at the top and base of the formation are yellow-brown and contain much limonite staining. The unit is slightly calcareous near the base. In the middle of the formation a medium bedded, dark brown to black quartzite unit is exposed. Thickness of the Victoria Formation in the Little Valley area is 80.0 feet. East Tintic Mountazns.-The Victoria Formation is chiefly fine to medium grained, gray dolomite, interlayered with medium grained, light brown, rusty weathering quartzite. The upper part of the formation is relatively free from sand and quartzite. Thickness of the Victoria Formation in the East Tintic Mountains is 278 feet (Morris and Lovering, 1961, p. 72).

Stratigraphic section of Victoria Formation measured in the Little Valley area of Long Ridge, Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964.

Victoria Formation Disconformable contact with Pinyon Peak Limestone. 1. Quartzite; tan to gray brown, weathers to a yellow-brown, medium to fine grained, abundant limonite staining, near the base the unit is slightly calcareous, middle of unit is characterized by a quartzite bed which weathers to dark brown or black, much of the unit is covered with float, slope forming, medium bedded. 80.0 Unconformable contact with Ajax Dolomite. SOUTHERN WASATCH MOUNTAIN THRUSTING 23

Pinyon Peak Limestone The Pinyon Peak Limestone was originally defined by G. F. Loughlin (1919) for Pinyon Peak in the Tintic Mining district. Errors have been found in the work of Loughlin which have necessitated changing the stratigraphic position of the Pinyon Peak (Morris and Lovering, 1961, p. 74). Several collections of fossils have been made from the Pinyon Peak and indicate a Late Devonian age (Beach, 1961, p. 42). The Pinyon Peak Limestone is not present in the Santaquin Canyon area of the Southern Wasatch Range but is exposed at the south end of West Mountain in a narrow belt extending two miles northward from the Keigley Quarries. The lower contact with the Opex Formation .~tWest Mountain is placed at the base of the first limestone unit. The base of the first dolomite bed of the Fitchville Formation marks the upper boundary. Lithology and Thickness Long Ridge (Little Valley).-A medium dark-brownish gray, thin to medium bedded, fossiliferous limestone comprises most of the Pinyon Peak found in this area. The base of the formation is slightly dolomitic and contains thin shale beds. Thickness of the Pinyon Peak Limestone in the Little Valley area is 51.5 feet. East Tintic Mountains.-Limestones of the Pinyon Peak are fine grained, medium to light gray, thin to massive bedded. The unit contains some argillaceous material and has a few flat pebble conglomerate beds near the base. Shaly lithology is more common near the lower part of the unit. Thickness of the Pinyon Peak Limestone in the East Tintic Mountains is 70.0 feet (Morris and Lovering, 1961, p. 76).

Stratigraphic section measured in the Little Valley area of Long Ridge, Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Pinyon Peak Limestone Conformable contact with Fitchville Formation. 2. Limestone; medium-dark gray, weathers medium gray, thin to medium bedded, medium crystalline, some fossiliferous beds (crinoid bryozoan fragments), ledge forming unit, contact is at base of first dolomite unit. 20.5 1. Limestone; dark gray, weathers medium brownish gray, fine to medium crystalline, thin to medium bedded, sonle fossiliferous beds near the top of the unit, thin shale beds are present near the base, somewhat dolomitic near the base. 31.0

Total 51.5 Disconformable contact with Victoria Formation.

Mississippian rocks crop out in this portion of the Southern Wasatch Mountains in a belt southward from the north end of Dry Mountain, across Santaquin Canyon to two miles northeast of Mona where they are truncated by the Wasatch fault. Mississippian strata are also exposed within a fenster 24 MICHAEL J. BRADY near Maple Dell Scout Camp on the east side of Payson Canyon and in the vicinity of the Keigley Quarries, at the south end of West Mountain. The Mississippian sequence of this area consists principally of cherty, fossiliferous limestones with minor dolomite, sandstone, shale, and quartzite units. Terminology used in the East Tintic Mountains by Morris and Lovering (1961) was employed in distinguishing formational units of this report. Stratigraphic sections including the Fitchville Formation, Gardison Lime- stone, Deseret Limestone, and Humbug Formation were measured by the writer in Santaquin Canyon and the Little Valley area of Long Ridge.

Fitchville Formation The Mississippian rocks that were originally defined as the lower member of the Gardner Formation have been separated into the Fitchville Formation, named from exposures on Fitchville Ridge in the East Tintic Mountains by Morris and Lovering (1961, p. 82). According to Morris and Lovering, fossils collected throughout the Fitch- ville date it as Early Mississippian, but Beach (1960) and Rigby and Clark (1962) state that rocks of Late Devonian age are now known to be included in the lower part of the formation. The Fitchville Formation is exposed along the western face of Dry Mountain, northward from the south side of Santaquin Canyon to east of Payson, just south of Red Point. Outcrops are also present on the east side of Payson Canyon, near Maple Dell Scout Camp, and on the south end of West Mountain in the vicinity of the Keigley Quarries. In the area of Santaquin Canyon the lower contact with the Opex Forma- tion is unconformable and is placed at the base of the first dolomite unit which contains a few coral remnants and does not display the mottled weathering surfaces typical of the Cambrian carbonates below. The lower boundary in the West Mountain area is gradational with the Pinyon Peak Limestone. The upper contact in Santaquin Canyon and West Mountain is at the base of the first abundantly fossiliferous unit of the Gardison Limestone. L~~hologyand Thickness Santayuin Canyon.-The lower part of the unit is a medium bedded, fine to medium crystalline dolomite containing remnants of crinoids, corals, and gastropods. Lack of mottled weathered surfaces distinguishes the Fitchville from the Opex Formation. The base of the formation is characterized by dolomite beds with thin interbedded shale layers and containing scattered chert nodules. The top ten feet of the formation is characterized by a limestone unit displaying irregular bedding surfaces. Thickness of the Fitchville Formation in Santaquin Canyon is 190 feet. Long Ridge (Little Valley).- In the Little Valley area the Fitchville is predominantly a light to dark gray, thin to massive bedded dolomite containing scattered corals, crinoids and gastropods. Near the top of the unit interbedded chert layers up to three inches in thickness are common. Some of the non- resistant slope-forming dolomite units have locally abundant argillaceous material. The base of the formation is slightly calcareous. Thickness of the Fitchville Formation in the Little Valley area is 233.5 feet. SOUTHERN WASATCH MOUNTAIN THRUSTING

East Tiiztjc Mo~iztui~z~.-Inthe East Tintic Mountains the Fitchville Formation is lithologically more complex than at Long Ridge and Santaquin Canyon and can be divided into eight distinctive units. Beginning at the bottom of the formation these units are: a sand grain marker bed, a blue flaky limestone, a white limestone, a blue shaly limestone, a black cherty dolomite, a sugary limestone, a pink lithographic limestone, and a curly limestone. Thickness of the Fitchville Formation in the East Tintic Mountains is 280.5 feet (Morris and Lovering, 1961, p. 84).

Stratigraphic section of Fitchville Formation measured on the south side of Santaquin Canyon, NW Sec. 32, T. 10 S., R. 2 E., by M. J. Brady, 1964. Fitchville Formation Conformable contact with Gardison Limestone. 5. Limestone; medium gray, weathers light gray, micritic to finely crystalline, thin to medium bedded, bedding at base and top has irregular bedding surfaces. 10.0 4. Dolomite; dark gray, weathers to dark blue gray, medium bedded, medium crystalline, fetid odor when broken, abundant chert nodules, remnants of horn corals distributed throughout base of unit. 106.0 3. Shale; black, weathers to dark gray, fissile, calcareous. 2.0 2. Dolomite; dark gray, weathers to light medium gray, fine to medium crystalline, thin to medium bedded, at base four 6" to one foot shale beds are interbedded with the dolomite, shales are dark gray to black, fissile and calcareous. 21.0 1. Dolomite; light medium gray, weathers light gray, fine to medium crystalline, medium bedded, slightly sucrosic texture, remnants of horn corals can be seen near the base of the unit, unit is not mottled like the Cambrian formations below. -51.0 Total 190.0 Unconformable contact with Opex Formation.

Stratigraphic section of Fitchville Formation measured in the Little Valley area of Long Ridge, SW Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Fitchville Formation Conformable contact with Gardison Limestone. 6. Dolomite; light gray, weathers to light gray with a pink tint, micritic to finely crystalline, massive bedded. 26.0 5. Dolomite; medium gray, weathers to light medium gray, finely crystalline, thin to medium bedded, interbedded blue gray cherts throughout the unit. 15.0 4. Dolomite; medium to dark gray, weathers medium gray, fine to medium crystalline, massive bedded, some fossil hash distributed throughout the unit. 70.0 3. Dolomite; medium gray, weathers light brown gray, medium crystalline, thin to medium bedded, lower part of unit has argillaceous partings, slope forming unit. 47.0 2. Dolomite; light brownish gray, weathers to buff and light gray, finely crystalline, massive bedded, some horn corals are present in the middle of the unit. 50.0 1. Dolomite; medium dark gray, weathers light gray, medium grained, thick bedded, slightly calcareous near the base. -25.5 Total 233.5 Conformable contact with Pinyon Peak Limestone. 26 MICHAEL J. BRADY

Gardison Limestone The Gardison Limestone was named by Morris and Lovering (1961, p. 89) for a section of highly fossiliferous limestone exposed on Gardison Ridge of the East Tintic Mountains. It is correlative with part of the stratigraphic units formerly called Madison Limestone in the Wasatch Range. Extensive faunas of Late Kinderhookian (?) and Osagean have been collected from the Gardison (Rigby and Clark, 1962, p. 19). Exposures of the Gardison are present along the western face of Dry Mountain, northward from the south side of Santaquin Canyon to east of Payson, near Red Point. Outcrops are also located in small fault blocks on the east side of Payson Canyon, across from Maple Dell Scout Camp, and at the south end of West Mountain in the vicinity of the Keigley Quarries. Contacts of the Gardison with the Fitchville Formation and Deseret Lime- stone are gradational and somewhat arbitrary at West Mountain and Santaquin Canyon. The to of the formation in Santaquin Canyon is placed at the base of a sequence of interbedded shale and limestone units of the Deseret. In the Little Valley area of Long Ridge the top boundary is drawn at the base of a series of thin bedded limestone. The lower contact is at the base of the first abundantly fossiliferous unit in the stratigraphic section. Lithology and Thickness Santuquin Canyon.--The Gardison Limestone at Santaquin Canyon consists of abundantly fossiliferous limestone with minor dolomite. The lower part of

East Tintic bne Ridge Santaquin Canyon

TEXT-FIGURE3.-Diagrammatic comparison of the Gardison Limestone between the East Tintic Mountains, Long Ridge, and Santaquin Canyon. Numbers correspond to units of the accompanying measured sections. SOUTHERN WASATCH MOUNTAIN THRUSTING 27 the formation contains abundant black chert nodules and thin intraformational conglomerate layers. The amount of chert increases towards the top of the formation where it is present in lenses up to five inches thick and varies from light- tan to black. Thickness of the Gardison Formation measured in Santaquin Canyon is 342.0 feet. Long Ridge (Little Valley).-The Gardison of the Little Valley area is domi- antly fossiliferous limestone with one dolomite unit 35 feet thick located 62 feet from the top of the formation. Chert is present but not so abundant as in Santaquin Canyon. Some indistinct cross-bedding is seen near the base of the formation. Thickness of the Gardison Formation measured in the Little Valley is 400.0 feet. East Tintic Mounlains.-The lower part of the Gardison in the East Tintic Mountains is characterized by thin to medium bedded, fossiliferous, chert free limestone. The formation becomes abundantly cherty and massively bedded near the top. No dolomites are present in the section of this area. ~hicknessof the ~ardison-~imestonein the East Tintic Mountains is 497.8 feet (Morris and Lovering, 1961, p. 91). A diagrammatic representation of the Gardison Formation located at the three areas discussed above is shown in Text-figure 3.

Stratigraphic section of Gardison Limestone measured on the south side of Santaquin Canyon, Sec. 32, T. 10 S., R. 2 E., by M. J. Brady, 1964.

Gardison Formation Conformable contact with Deseret Limestone. 9. Limestone; medium dark gray, weathers medium gray, finely crystalline. thin to medium bedded, abundant dark brown to black chert. 8. Limestone; medium gray, weathers medium blue gray, med~umcrystalline, medium bedded, abundant chert nodules. 7. Dolomite; dark gray, weathers to medium gray, fine to medium crystalline, chert lenses distributed throughout the unit. 6. Dolomite; medium gray, weathers to medium light gray, medium to coarsely crystalline, thin to massive bedded, intraformational conglomerates near the top of the unit, crinoidal fragments occur throughout the unit. 5. Limestone; medium to dark gray, weathers medium gray, fine to medium crystalline, thin to medium bedded, almost fissile in portions of the top, very fossiliferous, chert nodules common throughout the unit, most of the chert is black but in some places it is light brown or tan, platy weathering habit, semi-slope forming unit. 4. Dolomite; dark gray, weathers medium gray brown, fine to medium crystalline, medium to thick bedded, abundant chert lenses, a few fossil remnants can be seen. 3. Limestone; dark gray, weathers brownish gray, finely crystalline, thin to medium bedded, abundant nodules of black chert, fossiliferous (corals, crinoids, especially abundant). 2. Limestone; medium to dark gray, weathers to dark brown gray, medium bedded, fossiliferous, abundant argillaceous partings. 1. Dolomite; dark gray to black, weathers dark gray, medium crystalline, MICHAEL J. BRADY

medium to thick bedded, thin intraformational conglomerate beds in middle of unit, abundant corals. 37.0 Total 342.0 Conformable contact with Fitchville Formation.

Stratigraphic section of Gardison Limestone measured in the Little Valley area of Long Ridge, SW 1/4 Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Gardison Formation Conformable contact with Deseret Limestone. 5. Limestone (dolomite); medium dark gray, weathers medium gray, medium crystalline, medium to thick bedded, top of formation is extremely fossiliferous (crinoidal hash). 62.0 4. Dolomite; medium gray, weathers medium gray, medium crystalline, thin bedded, only scattered fossils. 35.0 3. Limestone; medium blue gray, weathers light medium gray, medium to coarsely crystalline, fossiliferous, medium bedded. 125.0 2. Limestone; dark gray, weathers medium gray, thick bedded, medium crystalline, fossiliferous, some chert is scattered throughout the unit, cliff forming unit. 103.0 1. Limestone; medium to dark gray, weathers medium gray, thin to medium bedded,. very fossiliferous, ledgy unit, some indistinct cross bedding. 75.0 Total 400.0 Conformable contact with Fitchville Formation.

Deseret Limestone The Deseret Limestone was named by James Gilluly (1932) from the Deseret mine in the Ophir district northwest of Eureka and is correlated with the Pine Canyon Limestone originally named by G. F. Loughlin (1919) in the Tintic district. Fossils collected from the Deseret indicate the formation is Late Mississip- pian (Meramecian) age (Morris and Lovering, 1961, p. 98). Exposures of the Deseret Limestone cross Santaquin Canyon just below Tinney Flat Campground and continue northward along the western face of Dry Mountain to Red Point, east of Payson. Less extensive outcrops are present on the east side of Payson Canyon near Maple Dell Scout Camp and at the south end of West Mountain, north of Keigley Quarries.

Litholoev"3 and Thickness Santaguin Canyon.-In Santaquin Canyon the Deseret is dominantly limestone with one 20 foot thick dolomite unit located 181 feet from the base. The lower boundary of the formation is drawn at the base of a gray-brown shale marker bed while the upper contact is at the top a massive, prominent cliff- forming, crinoidal limestone. Lenses of chert occur throughout the middle and upper part of the unit. Many of the beds are slightly sandy and show indistinct

cross-bedding.- Thickness of the Deseret in Santaquin Canyon is 703.0 feet. Long Ridge (Little Valley).--The Deseret of the Little Valley area is composed entirely of thin to medium bedded, fossiliferous limestone. Abundant chert lenses are present in the middle of the formation. The lower boundary SOUTHERN WASATCH MOUNTAIN THRUSTING with the Gardison is gradational and is placed at the base of a sequence of thin bedded cherty limestone. The upper contact is at the base of the first quartzite bed of the Humbug Formation. Thickness of the Deseret Formation in the Little Valley area is 600.0 feet. East Tintic Mountains.-The base of the Deseret Limestone is marked bv a black carbonaceous shale or shaly limestone followed by a sequence of masiive bedded, cherty limestones contaming locally abundant fine sand grams. The upper part of the formation is characterized by a medium bedded fossiliferous limestone contain~ngmuch nodular chert. Thickness of the Deseret Limestone in the East Tintic Mountains is 1,110 feet (Morris and Lovering, 1961, p. 96).

Stratigraphic section measured on the north side of Santaquin Canyon, SW Ya Sec. 29, T. 10 S., R. 2 E., by M. J. Brady. Deseret Formation Conformable contact with Humbug Formation. 9. Limestone; medium dark gray, weathers to medium gray, coarsely crystalline, massive bedded, fetid odor, cliff forming, crinoidal beds near top. 8. Limestone; dark gray, weathers to medium gray, medium to coarsely crystalline, medium to massive bedded, fetid odor. 7. Limestone (dolomitic); dark gray, weathers medium gray, fine to medium crystalline, thin to medium bedded, slope forming unit below cliff, slabby weathering habit, cherty. 6. Limestone; dark gray, finely crystalline, medium to thick bedded, fossiliferous (crinoid fragments and corals are especially abundant), unit contains interbedded black chert near the top. 5. Limestone; medium gray, weathers to medium gray, fine to medium crystalline, fossils distributed throughout unit, many beds show indistinct cross bedding, chert lenses are distributed throughout the unit, near the top the weathered surfaces of the beds tend to have an arenaceous texture, top of the unit is marked by a three feet thick calcareous sandy bed. 4. Dolomite; medium gray, weathers to gray brown, finely crystalline, abundant interbedded chert lenses, no evidence of fossils. 3. Limestone; medium to dark gray, weathers to medium gray, medium to thick bedded, medium crystalline, slaty weathering habit, abundant fossils (crinoids, horn corals), some cross bedding. 2. Shale; medium gray, weathers to brownish gray, calcareous, fissile, slope forming unit, some chert nodules. 1. Limestone; dark gray to black, weathers dark gray, micritic to finely crystalline, thin to medium bedded, chert nodules distributed throughout the unit, base of unit is marked by a gray-brown shale one foot thick. Total Conformable contact with Gardison Limestone.

Stratigraphic section of Deseret Limestone measured in the Little Valley area of Long Ridge, SW 1/4 Sec. 20, T. 10 S., R. 1 E., by M. J. Brady, 1964. Deseret Limestone Conformable contact with Humbug- Formation. 6. Limestone; medium gray, weathers medium gray, thick bedded, medium crystalline, some beds have an arenaceous texture, encrinal beds near top of unit, ledge forming units. 161.0 30 MICHAEL J. BRADY

5. Limestone; dark gray, weathers dark medium gray, medium crystalline, thin to medium bedded, interbedded chert, slope forming unit, fossiliferous (corals). 150.0 4. Limestone; medium gray, weathers medium l~ghtgray, medium to thin bedded, medium crystalline, argillaceous partings scattered throughout the unit. 106.0 3. Limestone; dark gray, weathers to medium blue gray, finely crystalline, medium bedded, some interbedded chert especially abundant near base of the unit, some encrinal beds at top of the unit. 97.0 2. Limestone (dolomitic); medium gray with tints of orange, finely crystalline, weathers light medium gray, some oolitic beds near the base, chert near middle of unit, medium to thick bedded. 20.0 1. Limestone; medium dark gray, weathers medium gray, fine to medium crystalline, cherty, some brachiopods, corals, thin bedded. 66.0 Total 600.0 Conformable contact with Gardison Formation.

Humbug Formation Humbug terminology was first used in the Tintic district by G. W. Tower, Jr. and G. 0. Smith (1899) for the Humbug intercalated series which is equivalent to the present day Humbug Formation. Fossils collected from the Humbug are of Late Mississippian age (Morris and Lovering, 1961, p. 106). The Humbug Formation crops out in Santaquin Canyon, just below Tinney Flat Campground, and northward along the crest and east slope of Dry Mountain to Red Point, east of Payson. Exposures are also present at the south end of West Mountain, north of the Keigley Quarries.

Li~holomr-, and Thickness Quartzites and sandstones interbedded with sandy, fossiliferous limestones and minor dolomites are characteristic of the Humbug Formation at Santaquin Canyon, Long Ridge (Little Valley), and the East Tintic Mountains. Beds range from one to six feet thick in Santaquin and Long Ridge, becoming slightly thicker in the Tintic district. Contacts are placed at the lowest and highest quartzite units. Thickness of the Humbug Formation in Santaquin Canyon is 598 feet. At Long Ridge, where only an incomplete section of Humbug is exposed, a section 347 feet thick was measured by Muessig, (1951). The section in the East Tintic Mountains is 597 feet thick (Morris and Lovering, 1961, p. 106). The Humbug Formation, which is not complete at Long Ridge, is the youngest complete Paleozoic formation exposed in Santaquin Canyon, and is therefore the last formation used for stratigraphic comparison.

Stratigraphic section of Humbug Formation measured on the north side of Santaquin Canyon, Sec. 32, T. 10 S., R. 2 E., by M. J. Brady, 1964.

Humbug Formation Conformable contact with Great Blue Limestone. 12. Sandstone; light brown to tan, calcareous, fine grained, medium bedded. 16.0 11. Limestone; medium light gray, weathers light tan-gray, micritic to finely crystalline, medium to thick bedded. 50.0 10. Limestone and quartzite interbedded; limestone is medium gray and weathers to blue gra , fine to medium crystalline; quartzite is gray-tan, beds range Lorn 6" to 4.5' in thickness. 177.0 SOUTHERN WASATCH MOUNTAIN THRUSTING 3 1

9. Dolomite and quartzite interbedded; dolomite is micritic to finely crystalline, light gray to buff, weathers to shades of pink and gray; quartzite is light brown to tan, beds range from 6" to seven feet. 8. Limestone; medium light gray, weathers to light tan gray, micritic to finely crystalline, thin to thick bedded. 7. Limestone and quartzite interbedded; same lithology as 10, beds range from 4" to 3.5 feet. 6. Quartzite; light brown to tan, fine grained, massive bedded. 5. Limestone; medium gray, weathers to light gray, finely crystalline. medium bedded, few horn corals are present. 4. Sandstone; dark brown to tan, weathers from brown to light tan. medium to thick bedded. friable and calcareous near the base, becomes more lithified and less calcareous towards the top, fairly non-resistant unit. 3. Dolomite; gray-brown, weathers to tan-gray to buff, fine to medium crystalline, medium to thick bedded, cherty near the top, slightly calcareous near the middle of the unit. 2. Limestone; medium gray, weathers to light gray brown, medium to coarsely crystalline, much sandy material, indistinct cross bedding medium bedded. 1. Sandstone; light brown gray, weathers to tan, fine grained, medium bedded, semi-friable in parts of the unit. Total 598.0 Conformable contact with Deseret Limestone.

Great Blue Limestone The Great Blue Limestone was named by Spurr (1895) but was later redefined by Gilluly (1932) to include the series of strata which overlie the Humbug Formation and are overlain by the Manning Canyon Shale. Fossils collected from the Great Blue indicate it is Late Mississippian age (Morris and Lovering, 1961, p. 112). Exposures of the formation are located in Santaquin Canyon, near Tinney Flat Campground, where only a partial section is present because of normal faulting. The only other outcrop within the area of this report is at the southeast end of West Mountain on the upper plate of the thrust shown on Text-figure 8. Contacts with the Humbug Formation and Manning Canyon Shale are gradational. The lower boundary is at the top of the first quartzite or sandstone bed below the limestone. The upper contact is placed at the base of thick sequence of black shales of the overlying Manning Canyon.

Lithology and Thickness The Great Blue can usually be divided into three members: the lower limestone member, the middle shale member, and the upper limestone member. Only a part of the lower limestone member is exposed in the area of this report. Thickness of the Great Blue Limestone in thc vicinity of the Southern Wasatch Mountains ranges from 2500 to 2800 feet (Rigby and Clark, 1962, p. 21). Because of lack of complete exposures of the formation the writer did not measure a section. For a more detailed description of lilhology the reader is referred to the discussion by Morris and Lovering, (1961, p. 107). MICHAEL J. BRADY

Manning Canyon Shale The Manning Canyon Shale was named by Gilluly (1932) from Manning Canyon in the Oquirrh Mountains. Fossils collected from the Manning Canyon indicate it includes the Late Mississippian and Early Pennsylvanian boundary (Morris and Lovering, 1961, p. 114). Exposures of the Manning Canyon are present on the south side of Santa- quin Canyon, near Tinney Flat Campground and on the upper plate of the Red Point thrust fault (Text-fig. 7). Evidences, but no outcrops of the Manning Canyon are seen on the east side of Payson Canyon, across from Maple Dell Scout Camp. Only partial sections are exposed within the area of this report.

Litholo~jand Thlrkrne~s The Manning Canyon consists of black to dark brown shale interbedded with quarttitic sandstone and some detrital limestone. A middle limestone member usually separates the upper and lower shale members. Thickness varies from' 100 to 1700 feet in the vicinity of the Southern Wasatch Mountains (Rigby and Clark, 1962). Because of lack of complete exposures of the formation the writer did not measure a stratigraphic section. For a more detailed description of lithology the reader is referred to the discussion by Morris and Lovering (1961, p. 113).

PENNSYLVANIAN-PERMIAN Oquirrh Formation The Oquirrh Formation was named by Gilluly (1932) for the extensive interbedded limestone and quartzite in the Oquirrh Mountains of Utah. The Oquirrh ranges in age from Early Pennsylvanian to Early Permian (Bissell, 1962, p. 26). Extensive outcrops of the Oquirrh Formation are present at the head of Santaquin Canyon, just south of Santaquin Meadows and on the east side of Payson Canyon, in the upper plate of the thrust fault shown in Text-fig. 6. The main part of West Mountain is comprised almost entirely of Oquirrh. Brecciated Oquirrh is also present in the fenstrr at the mouth of Santaquin Canyon (Text-fig. 5).

Lithology and Thickne~s The Oquirrh Formation has been separated into members by several individuals. Interbedded limestone, sandy limestone, sandstone, and quartzite are the predominant lithologies. The lower section is characterized by abundant limestone, with the upper part composed predominantly of sandstone and quartzite. The Oquirrh is the thickest formation in the Wasatch Mountains. A complete section measured by Baker (1947) in Provo Canyon, 40 miles to the north of the area of this report, totaled 26,000 feet. The writer has made no attempt to study the Oquirrh in detail. The reader is referred to a discussion by Bissell (1962, p. 26-33) for more information. SOUTHERN WASATCH MOUNTAIN THRUSTING 33

PERMIAN Kirkman Limestone The Kirkman Limestone was named by Baker and Williams (1940, p. 625) for Kirkman Hollow, a tributary to the Right Fork of Hobble Creek Canyon in the south-central Wasatch Mountains. Diagnostic fusulinids prove a Medial to Late Wolfcampian age for the Kirkman (Bissell, 1962, p. 34). The only outcrops of the Kirkman in the area of this report are present at the south end of the West Mountain, north of the Keigley Quarries on the lower plate of the thrust fault shown in Text-figure 8. L~hoiogyand Thickness The Kirkman is a dark gray to black, finely laminated limestone with quartzites present near the base. Many of the layers are brecciated and have been recemented by calcite. A complete section of the Kirkman is not present in West Mountain but a thickness of slightly less than 1500 feet was reported by H. J. Bissell (1962) in the type area. CRETACEOUS-TERTIARY North Horn Formation The North Horn Formation is Late Cretaceous and Paleocene age in the eastern part of the Wasatch Plateau. Evidence of Cretaceous age has not been found in this part of the Southern Wasatch Mountains (Hardy, 1962, p. 56). Scattered outcrops of the North Horn are present at the mouth of Santaquin Canyon, along the east face of Dry Mountain, and at the top of West Moun- tain. In the area of this report the conglomerates of the North Horn are in contact with Late Paleozoic rocks. At West Mountain and in the mouth of Santaquin Canyon the formation rests unconformably upon the Oquirrh Forma- tion and is overlain by Tertiary limestones and volcanics. On the east side of Dry Mountain the North Horn Formation is in contact with the Humbug Formation as the result of normal faulting. North Horn, Flagstaff, and Colton are difficult to distinguish because of similar lithology, rapid facies changes, and discontinuous exposures. Several questions still exist concerning relationships of these formations. Ltthology and Thickness The North Horn is a well-cemented, massive conglomerate, containing lenses of shale and silt. The conglomerate is composed mainly of quartzite, limestone and chert cobbles. A light pink to bright red color is characteristic of the formation in this area. Thickness of the North Horn is extremely variable, ranging from a few feet to several hundred feet. The writer has not attempted to study the North Horn Formation in detail. The reader is referred to a more detailed discussion by Hardy (1962, p. 57).

TERTIARY Flagstaff Limestone The Flagstaff Limestone is Paleocene and Eocene age (Hardy, 1962, p. 59). It is presumed to have formed as a result of deposition in a series of fresh water lakes. 34 MICHAEL J. BRADY

Exposures of Flagstaff are present at the head of Santaquin Canyon, south of Santaquin Meadows, and at the top of West Mountain, overlying the North Horn Formation. LithologJ The Flagstaff in this area consists of fresh water limestone, many beds of which are algal limestone, and interspersed shale, sandstone, and conglomerate. Thickness of the Flagstaff is variable and ranges from a few feet to a few hundred feet. Only a partial section of the formation is exposed within the area of this report. For a more detailed discussion of the Flagstaff Limestone the reader is referred to Hardy (1962, p. 59).

Colton Formation The Colton Formation was named by Spieker (1946, p. 139) for the sequence of red fluviatile shales and sandstones in the hills north of Colton, Utah. The Colton Formation of this area is probably entirely Eocene age (Metter, 1955, p. 140). The only exposure of the Colton is present at the head of Santaquin Canyon, east of Tinney .Flat Campground, where it overlies the Flagstaff Formation and is overlain by volcanics. Lithology Interbedded conglomerates, sandstones, and shales characterize the lithology of the Colton in this area. The color of the formation ranges from light pink to red with some thin gray to brown shale lenses locally present. Thickness of the Colton Formation as measured by Schoff (1951, p. 632) in the Cedar Hills is 580 feet. For a more detailed discussion of the Colton Formation the reader is referred to a discussion by Hardy (1962, p. 59).

Moroni Formation Extensive deposits of pyroclastic rocks and tuffaceous sandstones cover much of the area on the east side of Dry Mountain, in the vicinity of Santa- quin Meadows. Scattered outcrops of volcanic rocks are also present on the east side of Payson Canyon, near Red Point and at the mouth of Santaquin Canyon. Litholonr The Moroni Formation includes volcanic breccia, conglomerate, tuff, and tuffaceous sandstone which occur mainly in thick greenish-gray beds. Pyro- clastic rocks in this area contain more angular fragments than do those in other nearby areas. The composite thickness of the Moroni Formation is 2147 feet (Hardy, 1962, p. 61). Phillips (1962, p. 65) discusses the volcanic rocks of the Wasatch area in greater detail. SUMMARY AND CONCLUSIONS A comparison of the three stratigraphic sections discussed in this report shows an increase of formations, accompanied with increasing thickness,,west- SOUTHERN WASATCH MOUNTAIN THRUSTING 35 ward from Santaquin Canyon to the East Tintic Mountains (Text-fig. 4). The Opohonga Limestone, Fish Haven Dolomite, and Bluebell Formation found in the section of the East Tintic Mountains are not present at the Little Valley area of Long Ridge or Santaquin Canyon. The Pinyon Peak Limestone and Victoria Formation found at both the East Tintic Mountains and Long Ridge are not present in Santaquin Canyon. Excluding the Tintic Quartzite because of its uncertain thickness at Long Ridge, the section thickens 443 feet in the five miles from Santaquan Canyon to the Little Valley area of Long Ridge while in the 20 miles from Long Ridge to the East Tintic Mountains a thickness increase of 3377.3 feet occurs. The hiatal gap of the major Paleozoic unconformity in Santaquin Canyon, evidenced by Lower Mississippian strata deposited upon Late Cambrian age rocks, decreases westward. At Long Ridge Devonian strata rest on Upper Cambrian units while farther to the west in the East Tintic Mountains all of the systems are represented. This indicates that the three sections are in their correct positions relative to the geosyncline in which they were deposited. The Santaquin Canyon section being closer to the shelf and thus more affected by uplift or fluctuations in sea level. Carbonates of the stratigraphic section become more dolomitic from the East Tintic Mountains to Santaquin Canyon. A possible cause of this increase

East Tintic Long Ridge Santaquin Canyon Mountains C 5 mi 7

0 2

- -n El

, -i

$ 8

- Thickness 9926.8 feet

TEXT-FIGURE4.-Diagrammatic comparison of composite sections from the East Tintic Mountains, Long Ridge, and Santaquin Canyon. Gradual thinning of the section between the East Tintic Mountains and Santaquin Canyon is accomplished by wedging and by pre-Victoria Formation and Pinyon Peak Limestone erosion. 36 MICHAEL J. BRADY in dolomite is shallower water conditions nearer the shelf area of the geosyncline. Lithologically, strata at Long Ridge are more related to units in Santaquin Canyon than to those of the East Tintic Mountains. This is most easily ex- plained by the fact that Long Ridge is 15 miles east of the East Tintic Moun- tains and only five miles west of Santaquin Canyon. All of the evidence observed in the comparison of these three stratigraphic sections supports the conclusion that they are in close proximity to the relative positions in which they were deposited. There are no stratigraphic indications of major horizontal displacements having taken place. This does not preclude the possibility that all three areas have been displaced horizontally approximately equal distances, in which case they would have retained their same positions relative to each other. There is also the probability that minor movements would not be perceptible in this type of stratigraphic comparison.

STRUCTURE Basin and Range normal faults are the most prominent structural features in the Southern Wasatch area. The Wasatch Fault "zone", which is typical of the Basin and Range normal faults, has created the contrast in elevation between the Southern Wasatch Mountains and the adjacent valleys to the west. Generally, exposed beds have an eastward regional dip, with the exception of some units in West Mountain which have been overturned to the east. Prior to normal faulting the entire area was subjected to thrusting, folding, and faulting in a rather complex manner. The Wasatch Fault "zone" borders Loafer and Dry Mountains on the west, while on the east, gently dipping Tertiary and/or Cretaceous units abut against upturned Paleozoics.

PRE-LARAMIDE DEFORMATION Extensive deformation and metamorphism of the Farmington Canyon Com- plex on Dry Mountain indicate that pre-Big- Cottonwood Formation tectonism was more intense than any that followed. Epeirogenic movement followed the unconformable deposition of the Big Cottonwood Formation upon the crystalline rocks of the Farmington Canyon Complex. Subsequent erosion enabled basal Cambrian Tintic Quartzite to be deposited upon the Big Cottonwood Formation with slight regional angular unconformity. Gentle warping and uplift during Paleozoic time are recorded by changes in lithofacies of the sediments. The more severe movements exposed sediments to subaerial erosion, creating regional unconformities. The largest hiatd gap of the Paleozoic unconformities of this area is present in Santaquin Canyon where Early Mississippian strata rest unconformably upon Upper Cambrian rocks. Triassic and Jurassic strata are not exposed at Dry, Loafer, or West Moun- tains. Nearest exposures of Early Mesozoic rocks are present to the south on the south flank of Mt. Nebo, and to the northeast in Spanish Fork Canyon.

LARAMIDE DEFORMATION The most important relationship for dating Laramide orogenic events in the Southern Wasatch Mountains is present northeast of Nephi, on the North Fork of Salt Creek, where pre-Cretaceous folded and overthrust rocks pass beneath a cover of Price River Conglomerates (Hintze, 1962, p. 71). There- SOUTHERN WASATCH MOUNTAIN THRUSTING 37 fore, much of the Laramide deformation within the Southern Wasatch area can be dated as post-Arapien (Late Jurassic) and pre-Price River, probably of Late Montanan age (Schoff, 1951, p. 628). Later Cretaceous regional unconformities, the significance of which are not definitely known, are present immedately beneath the North Horn and South Flat Formations (Hardv. 1962). , - I The dominant Laramide structure in this area is the north-south trending anticlinal structure of Dry and Loafer Mountains which becomes overturned at the surface in the vicinity of Mt. Nebo. Steeply dipping and overturned Paleozoics which comprise the bulk of West Mountain are the remnant of a large fold resulting from Laramide deformation. Latest Mesozoic (?) and Cenozoic units rest with angular unconformity upon these beveled Paleozoics at the crest of the mountain. Thrust faults resulting from Laramide orogenic movements on Dry Moun- tain, the southern portion of Loafer Mountain, and at the south end of West Mountain were re-mapped by the writer and are discussed later in this report. A number of east-west normal faults having relatively small displacements are located on the east face of Dry Mountain. These faults are older than the Cenozoic block faulting and are probably related to Laramide deformation. Several pre-thrust normal faults are located in the fenster on the east side of Payson Canyon across from Maple Dell Scout Camp (Text-fig. 6).

CENOZOIC DEFORMATION Minor folds related to Cenozoic deformation are present just east of Dry Mountain in the vicinity of Payson Lakes. Cenozoic normal faults are the most prominent features of the Southern Wasatch Mountains. These faults trend north-south and are typical of the Basin and Range block faulting. The Wasatch fault "zone" borders Dry and Loafer Mountains on the east. A normal fault on the west face of Dry Mountain has enabled the North Horn Formation to be preserved on the downthrown side. Although only concealed evidence is available, West Mountain is also bounded by normal faults (Cook, 1961). Papers by Gilbert (1928), Nolan (1943), and Eardley (1951), have discussions of the Basin and Range structures of this area. THRL"1-S Santaquin Overthrust The mouth of Santaquin Canyon has previously been mapped by Eardley (1934) and Metter (1955) as a part of more extensive investigations of the Southern Wasatch Mountains. Thinning of the Ophir Shale along the west face of Dry Mountain, coupled with the presence of highly brecciated Car- boniferous rocks in an unusual position near Trumbolt Park, led Eardley (1934, p. 383) to postulate the existence of a major thrust fault which he termed the Santaquin Overthrust. Metter (1955) partially revised Eardley's mapping, although he concurred with the location of the overthrust. Hintze (1962) suggested that the anomalous position of the Carboniferous units against Cambrian and Precambrian strata may be the result of Cenozoic and/or Laramide normal faulting. Determination of the nature and amount of thrusting in this portion of the Southern Wasatch Mountains necessitated a more detailed study of the area at the mouth of Santaquin Canyon than had been made previously. 38 MICHAEL J. BRADY

Text-figure 5 is a geologic map of the mouth of Santaquin Canyon showing the Santaquin Overthrust as interpreted by the writer. Stratigraphic units within the map area range from Precambrian to Permian. The Big Cottonwood Formation (Precambrian?) is overlain by a Cambrian sequence of from Tintic Quartzite to Cole Canyon Dolomite. Portions of Mississippian Fitchville Formation and Gardison Limestone crop out in the central part of the area. The Oquirrh Formation (Pennsylvanian-Permian) is present in two separate exposutes. Quaternary alluvium and landslide material obscure some outcrops within the map area.

TEXT-FIGURE>.-Geologic map and structural cross-sections of the Santaquin Over- thrust, at the mouth of Santaquin Canyon. A fenster of Oquirrh Formation shows below the thrust surface within the canyon. Geology by the author. SOIJTHI'KN WASATCH MOIJNTAIN THRIJSTING 39

AlluriIm

Wdalid. debris

a Oquirrh Foxmation

Fitchvllls Fomtion

&brim Wndivided EEI Cole Cawon Ibl.

" Bluebizd Iblomite

ngmr Lblonita lxl Teutonic Ltasstone .-O~hir Fomtion

Big Cottomwd Foxmation --.i Thrust fault, barb. on overthrust

Noxmal fault

1'1:~~-FI(;IIRI. 5 (Continued)

Re-mapping revealed that previous workers overlooked exposures of Tintic Quartzite and Ophir Shale on the southwest side of Santaquin Canyon. Presence of these formations necessitated a change in previous interpretations of the nature of the Santaquin Overthrust. Location of the Santaquin Overthrust as mapped by the writer (Text-fig. 5) differs from the location previously prescribed by Eardley (1934) and Metter (1955), both of who111 postulated movement along the thrust at Santa- quin Canyon and on the west face of Dry Mountain restricted to the Ophir Shale. Both Eardley and Metter interpreted the situation on the northeast side of the Canyon where Oquirrh Formation is in contact with Precambrian and basal Cambrian as the result of pre-thrust normal faulting. They further con- 40 MICHAEL J. BRADY cluded that the top of this block of Oquirrh was sheared off during major thrusting along the Ophir Shale. It is proksed that the fault previously mapped as a pre-thrust normal fault is actually a northward exposure of the Santaquin Overthrust. The fol- lowing evidence supports this conclusion (Text-fig. 5). A. Detalled mapping on the northeast side of the canyon revealed that the fault has a northward dip. B. This writer's interpretation (Text-fig. 5) shows a normal stratigraphic sequence in the upper plate of the thrust on both sides of the canyon. C. Outcrops of Tintic Quartzite and Ophir Shale on the south side of the canyon indicate that movement was not entirely restricted to the Ophir Shale as was previously proposed by Eardley and Metter. D. Some beds of Tintic Quartzite have been overturned near the fault on the northeast side of the canyon. This overturning is probably the result of drag along the thrust. E. Where movement has occurred entirely in the Ophir Shale, as has happened within the canyon, the Ophir has been eliminated. F. Dernars (1956) found no evidence of overthrusting on the northwest face of Dry Mountain where Eardley and Metter had previously mapped- - the Santaquin Overthrust. G. Brecciation is more intense In the overridden Oquirrh than in Pre- cambrian and basal Cambrian units of the upper plate.

Dip of the fault plane changes from north to southeast on the northeast side of the canyon. The thrust plane has either been folded or changed attitude at this point in order to use the Ophir as a lubricant. Rocks in the upper plate of the thrust become older to the northwest until the fault is covered by landslide debris on the northeast side of Santaquin Canyon and is truncated by normal faulting on the southwest side. Normal faulting must also cut the thrust on the northeast side of the canyon under the landslide material (Text-fig.- 5). No definite directional properties were found within the map area. At one locat~onon the northeast side of Santaquin Canyon beds of Tintic Quartzite are overturned to the southeast, suggesting movement towards S. 4o0E. Slicken- sides at the base of the Teutonic Limestone, north of the map area, are oriented in an east-west direction. These slickensides are probably the result of bedding plant slippage in the Ophir Shale and are not directly related to the Santaquin Overthrust. The ~anta~uinOverthrust projects conveniently southward to the northern exposure of the Nebo Overthrust as mapped by Black (1965). It appears that the Nebo Overthrust is a southern extension of the Santaquin thrust. If the Santaquin Overthrust is a continuation of the Nebo Overthrust, movement along the fault must be approximately the same at both localities. On the basis of new mapping Black (1965, personal communication) postulates movement in excess of seven miles along the Nebo Overthrust. At Santaquin Canyon the thrust has placed the Big Cottonwood Formation (Pre- cambrian ?) in contact with Oquirrh (Pennsylvatlian-Permian). Stratigraphic displacement and the nature of the fault plane at Santaquin Canyon (Text-fig. SOUTHERN WASATCH MOUNTAIN THRUSTING 41

5) combined with the movement along the Nebo Overthrust as postulated by Black make it plausible to estimate at least seven miles of displacement. North-south striking normal faults which truncate the Santaquin Over- thrust are part of the Wasatch fault "zone". The main fault which has displaced Oquirrh rocks, placing them in juxtaposition to basal Cambrian units in the western part of the area (Text-fig. 5), has a throw of 5500-6000 feet (Eardley, 1933, p. 248). The east-west striking normal fault in the northeast corner of the map is related to earlier Lararnide deformation.

Payson Canyon Thrust Metter (1955), and Peterson (1956) each mapped thrust faults on the east side of Payson Canyon in the vicinity of Maple Dell Scout Camp but differ in their interpretations of the nature of faulting. Metter (1955) mapped two overlapping thrusts, each having the Oqu~rrhFormation in the upper plate. Peterson (1956) interpreted the situation as two imbricate thrusts as shown in Text-figure 6. Determination of the nature and amount of thrusting in this portion of the Southern Wasatch Mountains necessitated rechecking prevlous interpretations of the Payson Canyon thrusts. Text-figure 6 is a geologic map and structure cross-sections by Peterson (1956), with revisions by this writer, showing the Payson Canyon thrust located just east of Maple Dell Scout Camp. Stratigraphic units, which are lithologically similar to those in Santaquin Canyon (Text-fig. 4) include Tintic Quartzite (basal Cambrian) through the Moroni Volcanics (Tertiary). Cambrian and Mississippian formations mapped by Peterson (1956) were not distinguished in this report in order to show the nature of thrusting more clearly. Quaternary alluvium covers some outcrops near the canyon floor. Remapping of the thrust exposures revealed only one thrust fault as opposed to the two faults previously mapped by Metter (1955) and Peterson (1956). On the basis of the thrust's ex osure pattern in the central and southern portion of the map area, dip of te e fault plane at this location is to the southeast, as opposed to the northwest dip previously proposed by Peter- son (Text-fig. 6, structure cross-sections) . The anticlinal nature of the area shown in Text-f~gure6 is probably the result of compressional forces related to the thrusting. Folding also accounts for attitude variations of the fault plane. Thrusting has eliminated the shaly and thin bedded Great Blue Forma- tion along all exposures of the fault. Manning Canyon Shale which is present on the north side of the fenster was squeezed out to the south where Oqu~rrh is in contact with Cambrian and Mississippian strata (Text-fig. 6). Distance of thrusting in the Payson canyon area could not be determined although elimination of only two formations ~mpliesthat movement was not extensive when compared to that of the Santaquin or Nebo Overthrusts. Overturning to the southeast of beds in the Oquirrh Formation, north of the map area, indicate movement was towards S.45OE. An analysis of fracture patterns on both the upper and lower plates substantlate movement towards the southeast. 42 MICHAEL J. BRADY

EXPLANATION ${ Alluvium

Undifferentiated I volcanics

I Flagstaff [ Limestone

No t'l H n FohaPIon

Mississippian Undivided

Cambrian Undivided

-..a. .'.. Normal fault, concealed v--wa.. Thrust fault, barbs on overthrust J Interpretation by Peterson (1956)

/------

Interpretation by Brady (1964)

TEXT-FIGURE6.-Geologic map and structural cross-sections of the Paysan Canyon Thrust. Geology by Peterson (1956), with some rwisions by Brady (1964). D~fferences In interpretation are shown in cross-section A-B. SOUTHERN WASATCH MOUNTrlIN THRUSTING 4 3

Several pre-thrust normal faults are present withln the fenster and are truncated by the thrust (Text-f~g.6).

Red Point Thrust Red Point is located at the extreme north end of Dry Mountain on the west side of Payson Canyon (Text-fig. 1). Brown (1952) and Metter (1955) have each mapped a thrust in this area but d~fferin thelr interpretations of the trend of the fault. Brown suggests the Red Point Thrust has been displaced on the west by a r~ght-handtear fault that follows Payson Canyon. Metter extended the thrust from Red Point southward along the east slope of Dry Mountain. Further field work was necessary in the vicinity of Red Polnt to clarify thrust relations. Text-figure 7 1s a geologic map of the Red Point area by Brown (1952) with revisions and a structure cross-section by this wrrter. Rocks exposed within the map area range in age from Early Mississ~ppian to Quaternary. Mann~ng Canyon Shale (Mississ~ppian-Pennsylvan~an)and Oquirrh Formation (Pennsylvan~an-Permian) are exposed in the upper plate of the thrust with Mississippian formations from Fitchvllle through Humbug present in the lower plate. Discussions of these formations are found in the stratigraphic section of this report. Quaternary Lake Bonneville terrace gravels and Tertiary undifferentiated volcanics are also present within the map area. Remapping of the Red Point Thrust revealed that Metter (1955) in- correctly denti if led some unlts in the lower plate. A normal stratigraphic sequence exhibitrng no ev~denceof thrusting is exposed from Red Point southward along the east face of Dry Mountain. Trend of the Red Point Thrust, shown in Text-frgure 7 as mapped by this writer, is slm~larto Brown's interpretation. The thrust is truncated by Tertiary Basin and Range normal faulting on the west, whlle to the east, rt is apparently cut by a concealed fault that follows Payson Canyon. Termmation of the thrust in Payson Canyon, coupled w~thextremely different attitudes of Oquirrh beds on either side of the canyon, 1s evrdence supporting the presence of the concealed fault. The thrust exposure forms an arcuate pattern across Red Po~ntwhere it d~ps an average of 25' to the northwest (Text-fig. 7). Mannlng Canyon Shale is present along much of the fault exposure, indicating ~t probably served as a lubr~cantfor the thrusting. An asymetrical compressional fold within the Oqurrrh Format~onon the upper plate near the thrust plane suggests movement of the fault towards S.17OE. A structural cross-sect~on perpendicular to the axis of this fold IS shown in Text-figure 7. Distance of thrusting at Red Point could not be determrned.

White Lake H~lls Thrust Two thrust faults in the Wh~teLake H~lls,at the south end of West Mountain, previously mapped by Elison (1952) and Schindler (1952) were remapped to obtain evidence concerning nature, amount and directron of thrusting. 44 MICHAEL J. BRADY

"..--- A*.. Mom1 fault. wnwalad lbuat fault, barba on overthrust TEXT-FIGURE7.-Geologic map and structural cross-section of the Red Point Thrust near the mouth of Payson Canyon. Oquirrh rocks occur above the sole of the thrust slice, and various Mississippian formations occur below.

Text-figure 8 is a geologic map and structure cross-section of the White Lake Hills area by Elison (1952) and (Schlinder (1952) with revisions by this writer. Formations within the ma area range from Cambrian to Permian age. Discussions of these units are Pound in preceding pages. W'hite Lake Hills Thrust The White Lake Hills Thrust, named by Schindler (1952), is located in the northeast part of the map area (Text-fig. 8). As is evidenced by its exposure pattern the fault plane of the White Lake Hills Thrust dips gently to the southwest. Northeast overturning of Cambrian-Mississippian strata in the upper plate suggests movement was towards approximately N.70°E. Elison and Schindler SOUTHERN WASATCH MOUNTAIN THRUSTING each mapped tear faults in the upper plate of the thrust which substantiate northeastward movement. On the basis of thickness of stratigraphic section measured by White (1953) at West Mountain, displacement in excess of 16,000 feet was necessary to place Mississippian Great Blue Limestone in contact with Permian Kirkman Limestone (Text-fig. 8).

Noml fault---- -"T-.. . . Thrust fault

Terrace . Gravels

a. Kirkman Ihrmbug Fitchville Cole Canyon Dap.ar Tintic Limestone Formation Fonuation blomite Dolomite Ehlarteite

TEXT-FIGURE8.-Geologic map and structural cross-section of the White Lake Hills Thrusts, at the south end of West Mountain, north of Keigley Quarries. Geology is by Elison (1952) and Schindler (1952), with revisions by Brady. 46 MICHAEL J. BRADY

Keigley Quarries Thrust The Keigley Quarries Thrust, named by Elison (1952) forms an east- west exposure in the southern portion of the map area (Text-fig. 8). rill in^ has shown that the thrust plane dips 30' to the southwest in the subsurface (Dr. Thon Gen, 1965, personal communication). Doctor Gen stated that more recent drilling has revealed the thrust continues southward in the subsurface under Keigley Quarries where it assumes a regional westward dip. Cambrian strata in the south part of the map have been thrust upon the overturned Cambrian and Mississippian units of the upper plate of the White Lake Hills Thrust (Text-fig. 8). Thus, the Keigley Quarries Thrust lies structurally above and must be contemporaneous with or post-date the White Lake Hills Thrust. Abundant slickensides in the Tintic Quartzite, coupled with the regional westward dip of the thrust plane, indicate movement was towards N.4S0E. Although these slickensides are not exposed on the fault plane they probably resulted from bedding plane slippage within the Tintic during thrusting. On the basis of thickness of the stratigraphic section measured by White (1953) at West Mountain, movement along the fault in excess of 2000 feet was necessary to place basal Cambrian Tintic Quartzite juxtaposed to Mississippian Gardison Limestone. Another thrust has recently been located in the subsurface under the Keigley Quarries, south of the map area (Dr. Thon Gen, 1965, personal communication). This thrust, which is restricted to the upper plate of the Keigley Quarries Thrust, displaces formations in its upper plate 450 feet to the north and has a regional dip of less than 20° to the west.

West Mountain Thrust (?) Swanson (1952) and White (1953) have each mapped a fault at the south end of West Mountain which they termed the West Mountain Thrust. They interpreted this fault as one in which steeply dipping Oquirrh and Kirkman are thrust upon the Cambrian-Mississippian of the lower plate. In a more recent investigation Morris and Shepherd (1964) concluded the fault is a continuation of right-hand tear fault present in the subsurface in the vicinity of the Tintic Mining Dstrd. Remappng of the fault while gathering data for this report revealed little proof for either of the above interpretations. Relatively steep dip of the fault plane, indicated by the trend of the fault across the south end of West Moun- tain, combined with overturning of Oquirrh and Kirkman beds to the northeast, support a right-hand tear fault interpretation.

CAUSES OF THRUSTING IN THE SOUTHERN WASATCH AREA Two schools of thought concerning causes of deformation associated with the Laramide Orogeny. Numerous asymmetrical and overturned folds, having north-south trending axes, lead most writers to conclude that Laramide deformation was the result of regional eastward compressional forces. Recently, Eardley (1963) proposed that liqle, if any, horizontal compression occurred on a regional scale during the Laramide Orogeny. He postulates the occurrence of primary vertical uplifts due to megasills or megalaccoliths deep in the SOUTHERN WASATCH MOUNTAIN THRUSTING 47 silicic layer of the earth's crust, and that folds and thrusts are secondary features which resulted from gravitational sliding or mass movement down the flanks of these uplifts towards adjoining troughs. Eardley found that when thrust faults were charted in the Rocky Mountain area they proved to be, for the most part, marginal to the uplifts. In the Southern Wasatch area the dominant structural feature related to the Laramide Orogeny is the north-south trending anticlinal structure of Dry and Loafer Mountains which becomes overturned at the surface in the vicinity of Mt. Nebo. A similar structure is present at West Mountain where steeply dipping and overturned Paleozoic strata are the remnant of a large fold resulting from Laramide deformation. On the basis of overturning and asymmetry it is obvious these major folds at Dry, Loafer, and West Mountains were formed by forces predominantly from west to east. In the vicinity of

TEXT-FIGURE9.-Isopach map of the Oquirrh Basin Lower Permian rocks and relationships to the Weber Shelf, Emery Uplift, Western Utah Highland, Northeast Nevada Highland, and marginal thrust faults (after Bissell, 1962). 48 MICHAEL J. BRAD\-

Mt. Nebo where overturning is mainly to the southeast, deformation may have resulted from forces towards the southeast. Text-figure 10 is a regional force diagram constructed by placing arrows at right angles to the axes of folds and pointing them in the direction of overturning or asymmetry. A few of the arrows are oriented according to slickenside readings. Analysis of this diagram supports the conclusion that the majority of Lararnide folds in the vicinity of the Southern Wasatch Mountains were formed by regional compressional forces acting predominantly from west to east. Although some variation exists in the easterly orientation of the force arrows it should be noted that no significant folds were found which were asymmetrical or overturned in a westerly direction. It would seem logical if gravitational sliding were the major cause of Laramide thrusting that force arrows on a regional scale such as those shown in Text-figure 10 would be less regularly oriented. There is a possibility that analysis of folds within a larger area might substantiate Eardley's theory of gravitational sliding. DIRECTION OF THRUSTING IN THE SOUTHERN WASATCH AREA Few individuals have attempted to determine a specific direction of thrusting in the Southern Wasatch area. It is generally concluded on the basis of north-south trending asymmetrical and overturned folds that the majority of movement was the result of forces acting in an easterly direction. Force arrows shown in Text-figure 10 indicate the greater number of Laramide folds in the Southern Wasatch area were formed by compressional forces acting predominantly towards the east and northeast. Average orientation of these east-northeast trending force arrows is towards N.7o0E. Thus, major Laramide thrusting in the Southern Wasatch area must have been approximately towards N.70°E., although- some varlations of this direction are to be expected in local thrusts. The anticlinical structure of Dry and Loafer Mountains is asymmetrical to the east, suggesting it is the result of forces acting in that direction. At Mt. Nebo where overturning is predominantly to the southeast, the structure may have been affected by forces towards the southeast. There is also the possibility that rotation of the upper plate of the thrust or drag along its margins caused overturning to change from east to southeast In this area. Drag folds and slickensides associated with the Nebo Overthrust indicate movement towards N.65OE. (B. A. Black, 1965, personal communication). Slickensides and overturning of strata in the White Lake Hills area (Text-fig. 8) at the south end of West Mountain suggest displacement was towards N.45'-7o0E. Further evidence supporting major Laramide thrusting towards approximately N.7o0E. is the series of tear faults seen in Text-figure 9. All of these tear faults are oriented in a direction such that displacement along strike was in general towards N.70°E. Text-figure 10 shows some folding in the Southern Wasatch area is the result of forces acting towards the south and southeast. The majority of these folds are located in the vicinity of Salt Lake, but evidence substantiating a southward force is distributed thoughout the area. Average orientation of the south-southeast oriented arrows shown in the force map is towards S.21°E. Thus, if thrusting occurred in the Southern Wasatch area during this southeastward pulse of the Lararnide, displacement must have been approximately towards S.21 OE. SOUTHERN WASATCH MOUNTAIN 'THRUSTING

Southward thrusting was found at Red Point, located at the extreme north end of Dry Mountain, where an asymmetrical compressional fold within the upper plate indicated movement was towards S.17'E. (Text-fig. 7). Fracture patterns and overturning of strata in the upper plate of the Payson Canyon Thrust (Text-fig. 6) suggest movement was toward the southeast. Cohenour (1957) found evidence of extensive southward thrusting in the Sheeprock Mountains, ten miles west of Eureka. Cohenour (1957) postulates that eastward deformation preceded southward deformation in the Sheeprock Mountains. In the vicinity of Mt. Nebo structures resulting from eastward forces truncate and are superimposed upon structures formed by southward deformation in the Arapien Shale (B. A. Black, 1965, personal communication). This writer has also observed these structures found in the Arapien Shale on the south flank of Mt. Nebo and therefore concludes that the southward pulse of the Laramide Orogeny preceded the northeastward pulse in the Southern Wasatch area.

AMOUNT OF DISPLACEMENT OF THRUSTS IN THE SOUTHERN WASATCH AREA Crittenden (1961) assumes that the Nebo and Charleston Thrusts are one and the same and estimates 40 miles of displacement on the basis of a reconstruction of the Oquirrh Basin. Bissell (1965, personal communication) attributes the rapid thinning of the Oquirrh mainly to the shape of the basin of deposition and not to major thrusting. Text-figure 9 is Bissell's interpretation of the basin, with the Nebo-Charleston thrusts superimposed upon it. If Bissell's interpretation of the basin is correct, Crittenden has little basis for estimating movement as great as 40 miles. Eardley (1933) estimates approximately one mile of crustal shortening in the Mt. Nebo area is the result of thrusting. Johnson (1959) states that displacement on the Nebo Thrust need not exceed five miles. On the basis of newly mapped exposures of the Nebo Overthrust B. A. Black (1965, personal communication) postulates a minimum displacement of seven miles. The Santaquin Overthrust projects conveniently southward to the northern exposure of the Nebo Overthrust as mapped by Black (1965). If the Santa- quin Overthrust is a continuation of the Nebo Overthrust, movement along the fault plane must be approximately the same at both localities. At Santaquin Canyon the thrust has placed the Precambrian (?) Big Cottonwood Forma- tion in contact with Pennsylvanian-Permian Oquirrh: Stratigraphic displacement and the nature of the fault plane at Santaquin Canyon (Text-fig. 5) combined with the movement along the Nebo Overthrust as postulated by Black make it plausible to estimate at least seven miles of displacement for the Santaquin Overthrust. This writer found no evidence for estimating movement much greater than ten miles for major thrusting in the Southern Wasatch area. Ten miles of displacement could account for all the now known stratigraphic and structural relations. Comparison of the stratigraphic section in the upper plate at Santaquin Canyon, with sections on Long Ridge and in the East Tintic Mountains supports the conclusion that they are in close proximity to the relative positions in which they were deposited. There are no stratigraphic indications major horizontal displacements have taken place between these three sections. 5 0 MICHAEL J. BRADY

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TEXT-FIGURE10.-Arrows indicate force directions causing Laramide deformation. Most of the arrows are constructed at right angles to axes of folds and are pointed in the direction of overturning or asymmetry. The remainder of the arrows are oriented according to slickenside readings. SOUTHERN WASATCH MOUNTAIN THRUSTING 5 1

The diagram indicates two general directions of regional forces during the Laramide Orogeny. The majority of folds were formed by forces towards the east and northeast. Average orientation of these east-northeast trending force arrows is towards N.7O0E. Thus, major Laramide thrusting must have been approximately towards N. 70°E., although some variations of this direction are to be expected in local thrusts. A lesser amount of deformation is the result of forces acting towards the south and southeast. Most of these folds are located in the vicinity of Salt Lake, but evidence substantiating a southward force is present throughout the area. Average direction of the south-southeast oriented arrows is towards S. 21°E. Thus, if thrusting occurred during this southeastward pulse of the Laramide, displacement must have been approximately towards S.21°E.

SOURCES OF DATA Bissell, H. J., 1960, Geologic map .and sections of the Beverly Hills area, Utah County, Utah Unpublished. ---- , 1952, Stratigraphy and structure of the northeast Strawberry Valley Quad., Utah: Bull. Amer. Assoc. Petrol. Geol., v. 36, p. 575-634. Bissell, H. J., and Rigby, J. K., 1959, Geologic map of the southern Oquirrh Mountains, Tooele and Utah Counties, Utah: Guidebook 14, Utah Gml. Society. Black, B. A,, 1965, Personal communication; Brigham Young Univ. Brady, M. J., 1965, This paper. Bullock, K. C., 1951, Geology of Lake Mountain, Utah: Bull. 41, Utah Geol. and Mineral. Survey. Christiansen, F. W., 1952, Structure and stratigraphy of the Canyon Range, Central Utah: Geol. Soc. Amer. Bull., v. 63. Crittenden, M. D., and Baker, A. A., 1961, Geologic map of the Timpanogos Cave Quad., Utah: U. S. Geol. Survey. Eardley, A. J., 1934, Structure and physiography of the Southern Wasatch Mountains, Utah: Paper Mich. Acad. Sci., Arts, Letters, v. 19. Hardy, C. T., 1952, Eastern Sevier Valley, Sevier and Sanpete Counties, Utah: Utah Geol. and Mineral. Survey Bull. 43. Hintze, L. F. and Stokes, Wm. L., 1964, Geologic map of Utah. Ingham, V., 1961, Topographic and geologic map of the Rock Canyon area. Ingham, V., 1961, Topographic and geologic map of Rock Canyon. Unpublished. Johnson, K. D., 1959, Structure and stratigraphy of the Mount Nebo-Salt Creek area, Utah: Brigham Young Univ. Research Studies, Geol. Ser., v. 6, no. 6. Levy, E. and Cook, D. R., 1961, Generalized geology of the northern and central Oquirrh Mountains, Salt Lake and Tooele Counties, Utah: Guidebook to the Geology of Utah no. 16, Utah Geol. and Mineral. Survey. Marsell, R. E. and Thceet, R. L., 1961, Geologic map of Salt Lake County: Utah Geol. and Mineral. Survey. Metter, R. E., 1955, The geology of a part of the Southern Wasatch Mountains, Utah: unpub. Ohio State Univ. Ph.D. dissertation. Morris, H. T., and Lovering, T. S., 1961, Stratigraphy of the East Tintic Mountains, Utah: U. S. Geol. Survey Prof. Paper 361. Muessig, S. J., 1951, Geology of a part of Long Ridge, Utah: unpub. Ohio State Univ. Ph.D. dissertation. Peterson, D. J., 1956, Stratigraphy and structure of the west Loafer Mountain- upper Payson Canyon area, Utah: Brigham Young Univ. Research Studies, Geol. Set., v. 3, no. 4. Price, J. R., 1951, Strahgraphy and structure of Slate Jack Canyon area, Long Ridge, Utah: Compass Sigma Gamma Epsilon, v. 29, p. 73-80. Rawson, R. R., 1957, Geology of the southern part of Spanish Fork Peak Quadrangle, Utah: Brigham Young Univ. Research Studies, Geol. Ser., v. 4, no. 2. Rhodes, J. A,, 1955, Stratigraphy and structural geology of Buckley Mountain area, south-central Wasatch Mountains, Utah: Brigham Young Univ. Research Studies, Geol. Ser., v. 2, no. 4. White, B. O., 1953, Geology of West Mountain and northern portion of Long Ridge, Utah County, Utah: unpub. Brigham Young Univ. M.S. thesis. 5 2 MICHAEL J. BRADY

All three sections appear to have been displaced horizontally approximately equal distances during the Santaquin and Nebo Overthrusting, in which case, they would have retained their same positions relative to each other. There is the possibility that minor movements between these sections have taken place although they would not be perceptible in this type of stratigraphic comparison.

REFERENCES CITED Abbott, W. 0. 1951, Cambrian Diabase Flow in central Utah: Compass Sigma Garnma Epsilon, v. 29, p. 5-10. (More complete report of same title available as unpub. M.S. thesis, Brigham Young University, 1951.) Baker, A. A. and Williams, J. S., 1940, Permian in parts of Rocky Mountain and Colorado Plateau regions: Amer. Assoc. Petrol. Geol. Bull., v. 24, p. 617-635. Beach, G. A,, 1961, Late Devonian and Early Mississippian biostratigraphy of central Utah: Brigham Young Univ. Geol. Studies, v. 8. p. 37-53. Bissell, H. J., 1952, Stratigraphy and structure of the northeast Strawberry Valley Quadrangle, Utah: Buli. Amer. Assoc. Petrol. Gml., v. 36, p. 575-634. , 1953, Summary of the structural evolution of the Utah Lake Basin, central Utah: Compass of Sigma Gamma Epsilon, v. 31, p. 23-24. ---- , 1959, North Strawberry Valley sedimentation and tectonics: Intermountain Assoc. Petrol. Geol. Guidebook, 10th Annual Field Conf., p. 159-167. ---- 1962, Pennsylvanian-Permian Oquirrh Basin of Utah: Brigham Young Univ. dl.Studies, v. 9, pt. 1, p. 24-48. Black, B. A., 1965, Nature, direction, and amount of displacement of the Nebo Thrust, Southern X'asatch Mountains, Utah: Brigham Young University Geol. Studies, v. 12, p. 55-89. Brimhall, W. H., 1951, Geology of the Deer Creek Reservoir area: unpub. Uni- versity of Arizona M.S. thesis, 71 p. Brown, R. S., 1952, Geology of the Payson Canyon area, Southern Wasatch Moun- tains, Utah: Compass of Sigma Gamma Epsilon, v. 29, p. 331-339. Bullock, K. C., 1951, Geology of Lake Mountain, Utah: Utah Geol. and Mineral. Survey, Bull. 41, 46 p. Christiansen, F. W. and Costain, J. K., 1961, Structural evolution of the Gilson Mountains and Canyon Range, west-central Utah: Proc. Utah Acad. Sci., Arts, Letters, v. 38, p. 115-116. Cohenour, R. E., 1957, Geologic map of the Sheeprock Mountains, Tooele and Juab Counties, Utah: Utah Gml. and Mineral. Survey, Bull. 63, 201 p. Cook, K. L., 1961, Regional gravity survey along the Central and Southern Wasatch front, Utah: U. S. Geol. Survey Prof. Paper 316-E, p. 75-89. Crittenden, M. D., Jr., 1961, Magnitude of thrust faulting limits in northern Utah: U. S. Geol. Survey Prof. Paper 424-D, p. 128-131. Demars, L. C., 1956, Geology of the northern part of Dry Mountain, Southern Wasatch Mountains, Utah: Brigham Young Univ. Research Studies, Geol. Ser., v. 3, no. 2, 49 p. Eardley, A. J., 1933, Stratigraphy of the Southern Wasatch Mountains, Utah: Mich. Acad. Sci. Papers, v. 18, p. 307-344. ----, 1934, Structure and physiography of the Southern Wasatch Mountains, Utah: Mich. Acad. Sci. Papers, v. 19, p. 377-400. , 1939, Slotted templet for resolving crustal movements: Jour. of Geol., v. 47, no 5, p. 546-554. ----, 1944, Geology of the north-central Wasatch Mountains, Utah: Geol. Soc. Amer. Bull., v. 55, p. 819-894. , 1951, Structural Geology of North America: Harper Bros., New York, 624 p. ----, 1963, Relation of uplifts to thrusts in the Rocky Mountains: Amer. Assoc. Petrol. Geol. Memoir no. 2. D. 209-219. Eaton, H. J., 1929, structural ieatures of Long Ridge and West Mountain, central Utah: Amer. Jour. Sci., v. 18, p. 71-79. Elison, J. H., 1952, Geology of the Keigley Quarries and the Genola Hills area, Utah: un~ub.Brigham Youna Univ. M. S. thesis. 76 D. Gilbert, G. K., 192& ~tudies'bf Basin-Range ~tructure:U. S. Geol. Survey Prof. Paper 153, 92 p. SOUTHERN WASATCH MOUNTAIN THRUSTING 5 3

Gilluly, James, 1932, Geology and ore deposits of the Stockton and Fairfield Quad- rangles, Utah: U. s. Geol. Survey Prof. Paper 173, 171 p. Hardy, C. T., 1962, Mesozoic and Cenozoic stratigraphy of north-central Utah: Brigham Young Univ. Geol. Studies, v. 9, pt. 1, p. 50-64. Harris, H. D., 1959, Late Mesozoic positive area in western Utah: Amer. Assoc Petrol. Geol. Bull., v. 43, p. 2636-2652. Hintze, L. F., 1962a, Structure of the Southern Wasatch Mountains and vicinity, Utah: Brigham Young Univ. Geol. Studies, v. 9, pt. 1, p. 70-80. , 1962b, Precambrian and Lower Paleozoic rocks of north-central Utah: Brig- ham Young Univ. Geol. Studies, v. 9, pt. 1, p. 8-16. Johnson, K. D., 1959, Structure and stratigraphy of the Mount Nebo-Salt Creek area, Utah: Brigham Young Univ. Research Studies. Geol. Ser., v. 6, no. 6, 49 p. Lindgren, W. and Loughlin, G. F., 1919, Geology and ore deposits of the Tintic Mining District: U. S. Geol. Survey Prof. Paper 107, 282 p. Loughlin, G. F., 1913, Reconnaissance in the Southern Wasatch Mountains, Utah: Jour. Geol., v. 21, p. 436-452. Metter, R. E., 1955, The geology of a part of the Southern Wasatch Mountains. Utah: unpub. Ohio State Univ. Ph.D. dissertation, 244 p. Migliaccio, R. R., 1958, Middle Cambrian trilobites from the Ophir Shale of central Utah: The Compass of Sigma Gamma Epsilon, v. 35, no. 4, p. 298-301. Morris, H. T., and Lovering, T. S., 1961, Stratigraphy of the East Tintic Mountains, Utah: U. S. Geol. Survey Prof. Paper 361, 145 p. Morris, H. T., and Shepherd, W. M., 1964, Evidence for a concealed tear fault with large displacement in the East Central Tintic Mountains, Utah: U. S. Geol. Survey Prof. Paper 501-C, p. C19-C21. Muessig, S. J., 1951, Geology of a part of Long Ridge, Utah: unpub. Ohio State Univ. Ph.D. dissertation, 213 p. Nolan. T. B., 1943. The Basin and Range Province in Utah, Nevada, and California: U. S. Geol. Survey Prof. Paper 197.~.p. 141-196. Peterson, D. J., 1956, Stratigraphy and structure of the west Loafer Mountain-upper Payson Canyon area, Utah: Brigham Young Univ. Research Studies, Geol. Ser., v. 3, no. 4, 40 p. Peterson, D. O., 1953, Structure and stratigraphy of the Little Valley area, Long Ridge, Utah: unpub. Brigham Young Univ. M.S. thesis, 96 p. Phillips, W. R., 196 , Igneous rocks of north central Utah: Brigham Young Univ. Geol. Studies, v. 9, pt. 1, p. 65-69. Price, J. R., 1951, Stratigraphy and structure of the Slate Jack Canyon area, Long Ridge, Utah: Compass of Sigma Gamma Epsilon, v. 29, p. 73-80. Rigby, J. K. and Clark, D. L., 1962, Devonian and Mississippian Systems in central Utah: Brigham Young Univ. Geol. Studies, v. 9, pt. 1, p. 17-25. Schlindler, S. F., 1952, Geology of the White Lake Hills, Utah: unpub. Brigham Young Univ. M.S. thesis, 66 p. Schoff, S. L., 1951, Geology of the Cedar Hills: Geol. Soc. Amer. Bull., v. 62, p. 619-646. Smith, C. V., 1956, Geology of the North Canyon area, Southern Wasatch Moun- tains, Utah: Brigham Young Univ. Research Studies, Geol. Ser., v. 3, no. 7, 32 p. Smith, G. O., 1900, Geology of the Tintic Mining District: U. S. Geol. Survey Tintic Folio, no. 65, 4 p. Spieker, S. M., 1946, Late Mesozoic and Early Cenozoic history of central Utah: U. S. Geol. Survey 16th Ann. Rep., pt. 2, p. 343-455. Stokes, Wm. Lee, 1964, Southern termination of the Wasatch Range: Utah Geol. Soc. Guidebook to the Geology of Utah, no. 18, p. 53-55. Swanson, J. W., 1952, Geology of the southern portion of West Mountain, Utah: unpub. Brigham Young Univ. M.S. thesis, 69 p. Tower, G. W. and Smith, G. 0.. 1899, Geology and mining industry of the Tintic District, Utah: U. S. Geol. Survey 19th Ann. Rcp., pt. 3, p. 609-767. White, B. O., 1953, Geology of West Mountain and northern portion of Long Ridge, Utah County, Utah: unpub. Brigham Young Univ. M.S. thesis, 187 p.

Manuscript received May 6, 1965