Stratigraphy and Structure 

of the Dinkey Creek Roof 

Pendant in the Central 

Sierra Nevada, California 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 524-B 

Stratigraphy and Structure 

of the Dinkey Creek Roof 

Pendant in the Central 

Sierra Nevada, California 

By R. W. KISTLER and P. C. BATEMAN 

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 524-B 

Multiple folding in the Dinkey Creek 

roof pendant of the central Sierra Nevada 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEW ART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 
CONTENTS 

Page 

Abstract __________________________________________ _ B 1 Formations-Continued 

Introduction ______________________________________ _ 1 Silicated marble, calc-silicate hornfels, and tactite 

Bordering intrusive rocks ___________________________ _ 1 inclusions in biotite-hornblende quartz monzonite_ 

Formations _______________________________________ _ 3 Diorite sills and dikes __________________________ _ 

Gray marble __________________________________ _ 3 Structure _________________________________________ _ 

Calc-silicate rock ______________________________ _ 3 Structure diagrams _____________________________ _ 

Lower member ____________________________ _ 3 Initial orientation of the folds ___________________ _ 

Upper member ____________________________ _ 3 Extent and cause of the deformations ________________ _ 

Biotite-andalusite hornfels ______________________ _ 3 Summary and conclusions ___________________________ _ 

White quartzite _______________________________ _ 3 References cited ______________________ - ____ - ____ - __ _ Schist ________________________________________ _ 4 

ILLUSTRATIONS 

Page 

B4 

4 

4 

7 

7 

11 

12 

14 

PLATE 1. Geologic map, block diagram, and map showing metamorphic structures of the Dinkey Creek roof pendant, central Page 

Sierra Nevada, Calif___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ In pocket 

FIGURE 1. Generalized geologic map of the central Sierra Nevada _________________________________________ --------__ B2 

2. Crossbedding in white quartzite ___________________________________________________________________ -___ 4 

3. Typical first folds with cleavage parallel to axial surfaces _______________________________________ ---------- 6 

4. Typical second fold in thin-bedded marble and hornfels ___ :________________________________________________ 7 

5. Second fold in thin-bedded marble and hornfels__________________________________________________________ 7 

6. Later folds crossing earlier folds iri thin-bedded schist and quartzite __________________________________ ---___ 8 

7. Collective diagrams of structural elements in the Dinkey Creek roof pendant ______________________ -_-----_-- 9 

8. Subareas with a single cylindrical fold axis of bedding in the Dinkey Creek roof pendant _________________ -___ 10 

9. Synoptic diagrams of first folds in the Dinkey Creek and Log Cabin roof pendants, Sierra Nevada, Calif_______ 13 

ni 

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

STRATIGRAPHY AND STRUCTURE OF THE DINKEY CREEK ROOF PENDANT IN THE 

CENTRAL SIERRA NEVADA, CALIFORNIA 

By R. W. KrsTLER and P. C. BATEMAN 

ABSTRACT 

The Dinkey Creek roof pendant, about 50 miles northeast of 

Fresno in the central Sierra Nevada, Calif., is composed of a 

sequence of five sedimentary formations of Paleozoic or Mesozoic (pre-Cretaceous) age, which bordering plutons have thermally metamorvhosed to the hornblende hornfels facies. 

During three successive tectonic episodes, three fold systems 

were formed. The first folds are overturned and have tightly 

appressed limbs; axial surfaces strike about N. 5° E. and dip 

45° W. The second folds are open and have simple hinges; 

near-vertical axial surfaces strike about N. 200 W. The third 

folds are open and have simple hinges; near-vertical axial surfaces strike about N. 60° W. The deformations that produced 

the folds are thought to be regional because all three fold s,ystems appear to have countervarts of similar style and axial 

surface orientation in other metamorphic remnants of the 

central Sierra Nevada. 

INTRODUCTION 

The Dinkey Creek roof pendant in the central Sierra 

IN evada, Calif., belongs to a belt of pendants composed 

chiefly of miogeosynclinal strata, which trend southeastward through the range for at least 100 milesfrom near Huntington Lake at the north to Mineral 

King a:t the south (Bateman and others, 1963; Krauskopf, 1953). The distinctive lithologies of the formations, the presence of crossbeds in a quartzite formation, 

and a spectacular display of minor structural features 

in the Dinkey Creek roof pendant make it possible to 

determine the stratigraphy, geometry, and history of 

folding in rocks at the north end of this belt. 

The pendant is in eastern Fresno County about 50 

miles northeast of Fresno and 4 miles north of the 

Dinkey Creek resort area at an altitude of 7,600 to 9,700 

feet (fig. 1). It underlies an area of about 8 square 

miles, but about 1 square mile in a long narrow curved 

septum at the southwest was not studied. The base for 

the geologic map of the pendant (pl. 1) is the manuscript compilation of the Huntington Lake 15-minute 

quadrangle, which is at a scale of 1 : 20,000. The scale 

has been reduced to 1 : 31,680 for publication. Most of 

the pendant is accessible by a good vehicle trail (fourwheel-drive road) that branches east from California 

State Highway 168 at Tamarack summit, about midway 

between Shaver Lake and Huntington Lake. The east 

end of the pendant can be reached by a very rough vehicle trail that runs northwest from the Dinkey Creek 

resort area. 

The objectives of this study are ( 1) to determine the 

stratigraphic sequence of the strata in the roof pendant 

and the intrusive sequence of the plutons that border 

the pendant, (2) to determine the geometry and history 

of deformation of the pendant rocks, and ( 3) to deter: 

mine whether the structural features in the pendant 

were caused by the emplacement of the bordering 

plutons and are confined to this pendant or whether they 

are represented in other metamorphic remnants and are 

of regional extent. 

BORDERING INTRUSIVE ROCKS 

The part of the pendant that was mapped is triangular shaped, and each side is in contact with diff~r~nt 

plutons of granitic rock (pl. 1). Hornblende-bwtlte 

granodiorite, "Dinkey Creek" type, lies along the north~ 

west side; porphyritic biotite granite along the northeast side; garnet-bearing biotite granite along the west 

part of the south side; and biotite-hornblende quartz 

monzonite along the east part of the south side. Small 

masses of diorite of varied texture and composition, and 

older than either the hornblende-biotite granodiorite, 

"Dinkey Creek" type, or the porphyritic biotite granite, 

lie along the northeast side of the pendant. Designations of the plutonic rocks follow Krauskopf (1953) .. 

The biotite-hornblende quartz monzonite is, in fact, a 

complex of metamorphic and intrusive rocks, including 

diorite. 

The sequence of intrusion is: ( 1) Diorite, (2) hornblende-biotite granodiorite, "Dinkey Creek" type, (3) 

porphyritic biotite granite and garnet-bearing bio~ite 

granite, and ( 4) biotite-hornblende quartz mon~omte. 

The small masses of diorite along the northeast s1de of 

the pendant are intruded only by the porphyritic biotite 

granite and by the hornblende-biotite granodiorite, 

"Dinkey Creek" type. The porphyritic biotite granite 

and the garnet-bearing biotite granite both intrude the 

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SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

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Granitic rocks 

Includes diorite and gabbro 

Ultramafic rocks 

Largely serpentine 

Eugeosynclinal metamorphic 

rocks 

Includes metasedimentary 

and metavolcanic strata 

EXPLANATION 

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N 

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Contact 

Undivided stratified rocks 

Miogeosynclinal rocks 

Chiefly metasedimentary rocks 

Metamorphic and sedimentary rocks 

Chiefly miogeosynclinal metasedimentary 

strata in the eastern Sierra Nevada and 

White Mountains; eugeosynclinal metasedimentary and metavolcanic strata in 

the Western metamorphic belt. Strata 

in the northern White Mountains are 

probably Precambrian 

Dashed where approximately located 

Fault 

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FIGURE !.-Generalized geologic map of the central Sierra Nevada showing the location of the Dinkey Creek and other roof 

pendants. 
STRATIGRAPHY, STRUCTURE, DINKEY CREEK ROOF PENDANT, SIERRA NEVADA, CALIFORNIA B3 

hornblende-biotite granodiorite, "Dinkey Creek" type, 

and the biotite-hornblende quartz monzonite intrudes 

both the porphyritic granite and the hornblende-biotite 

granodiorite, "Dinkey Creek" type. The age relation 

of the biotite-hornblende quartz monzonite to the 

garnet-bearing biotite granite was not established, but 

the biotite-hornblende quartz monzonite is believed to 

be the older. Although the porphyritic biotite granite 

contains no garnet in the area shown on plate 1, it does 

contain garnet about 2 miles east of the pendant near 

Second Dinkey Lake; this fact suggests close relationship to the garnet-bearing biotite granite. 

FORMATIONS 

The pendant is composed of five formations of metamorphosed sedimentary rocks; it also contains a few 

dikes and sills of dark fine-grained diorite. The stratigraphic sequence from youngest to oldest is as follows: 

5. Schist 

4. White quartzite 

3. Biotite-andalusite hornfels 

2. Calc-silicate rock 

1. Gray marble 

These formations are lithologically distinctive, and 

all contacts between formations are sharp. The strata 

were derived from a sequence of calcareous, argillaceous, 

and arenaceous sediments that were deposited in a 

miogeosynclinal environment. Because most formations have been thickened by folding and thinned by 

attenuation of the less competent beds, original stratigraphic thicknesses cannot be determined with certainty. The entire exposed sequence may have had a 

stratigraphic thickness of only 3,000 to 4,000 feet. The 

stratigraphic thickness of the white quartzite formation 

may have been in the order of 1,500 to 2,000 feet, the 

biotite-andalusite hornfels 800 to 1,000 feet, and the 

calc-silicate rock about 200 feet; the gray marble and 

schist formations are incompletely exposed. 

The mineral assemblages are compatible with the 

hornblende hornfels facies of thermal metamorphism 

( Fyfe and others, 1958, p. 205- 211) . Calcareous rocks 

are composed of various combinations of quartz, diopside, calcite, wollastonite, garnet, epidote, microcline, 

plagioclase, hornblende, and scapolite; pelitic rocks of 

combinations of quartz, muscovite, biotite, andalusite, 

and plagioclase; and quartzofeldspathic rocks of 

combinations of quartz, muscovite, biotite, microcline, 

and plagioclase. 

Most rocks have a granoblastic texture, although a 

preferred orientation of micaceous minerals has persisted in some schistose specimens. Hornfels are generally equigranular and fine grained, but porphyroblasts of andalusite characterize the biotite-andalusite 

hornfels formation and argillaceous layers in the white 

quartzite and schist formations. Tactite adjacent to intrusive contacts and some calc-silicate rocks in the interior of the pendant are coarse grained. 

GRAY MARBLE 

The lowest exposed format ion is finely lan1inated 

medium-gray marble. Individual laminae, generally 

an eighth of an inch or less in thickness, differ in grain 

size and shade. The formation is composed almost entirely of calcite and is probably clastic. Crossbeds appear to be present, but shears, parallel or subparallel 

to bedding, have a similar appearance to the crossbeds 

and make them unreliable for determining top directions. Small veins of white calcite, generally en 

echelon, are locally present. 

CALC-SILICATE ROCK 

This formation consists of two members separated 

by a sill of dark fine-grained diorite. 

Lower member.-The part below the sill is a highly 

contorted sequence of interbedded marble, calc-silicate 

hornfels, and quartzofeldspathic hornfels. In outcrop, marb_le layers are buff to gray, and the calc-silicate 

hornfels layers are stained reddish brown by iron oxides. 

Individual layers are generally half an inch to several 

inches thick. Some layers of hornfels represent two 

or more layers that have been brought together by isoclinal folding or by the squeezing out of intervening 

marble layers. 

Upper member.-The part a;bove the sill consists of 

well-bedded buff marble and thin beds and lenses of 

areenish calc-silicate rock. Marble makes up at least !:> 

75 percent of the member. The calc-silicate rock is 

coarser grained than typical hornfels, and in places the 

layers are broken and boudined. 

BIOTITE-ANDALUSITE HORNFELS 

The biotite-andalusite hornfels formation is composed 

of remarkably uniform rock that is mottled light and 

dark gray. This mottling is on a scale of fractional 

parts of an inch and is caused by andalusite poikiloblasts. Originally the formation was ·an argillaceous 

shale or mudstone. Because the beds differ only 

slightly in composition and color, careful observation 

is required to identify bedding. In most outcrops the 

bedding is intricately contorted. 

WHITE QUARTZITE 

The most widespread unit in the pendant is composed 

chiefly of light-gray to buff quartzite, which is conspicuously crossbedded in many outcrops (fig. 2). 
B4 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

Within the quartzite are darker layers of pelitic hornfels, which comprise less than 5 percent of the formation. At the bottom of the formation and transitional 

~o the underlying biotite-andalusite hornfels formation, 

IS 10-15 feet of buff silicated marble and calc-silicate 

hornfels. Other calcareous layers and lenses are present within the quartzite, especially in the southeast end 

of the pendant where calcareous beds have been converted by contact metasomatism to scheelite-bearing 

tactite. 

FIGURE 2.-Crossbedding in white quartzite. Beds are vertical; tops are to the right. 

Crossbeds in the quartzite occur in layers that range 

from less than half an inch to more than a foot thick. 

~ost crossbeds appear concave upward, but some appea.r 

lmear and some sigmoid. Those that are concave upward were used to determine tops of beds. Quartz 

veins, commonly in gash systems arranged en echelon, 

are locally abundant. Deformation may obscure the 

crossbedding by producing, in areas of tight minor 

folds, shears that mimic the depositional structure. In 

determining top directi'ons we have taken great care to 

ascertain that true crossbeds were being observed. 

SCHIST 

The stratigraphically highest unit in the pendant 

consists chiefly of thinly interbedded layers of very dark 

gray schist and light-gray to buff quartzite. Individual 

layers generally range in thickness from less than oneeighth of an inch to more than an inch. Crossbedded 

quartzite layers several feet thick are locally present. 

Also present are three layers composed of buff garnetiferous marble and buff to greenish calc-silicate hornfels 

which are shown separately on the geologic map. 

The unit is one of the Least competent in the pendant, 

and the original layering is strongly disrupted. Bondins and discontinuous lenses of quartzite are common; 

in places they pa.rallel a secondary foliation transverse 

to the original bedding. Small-scale folds are conspicuous throughout the unit. 

SILICATED MARBLE, CALC-SILICATE HORNFELS, AND 

TACTITE INCLUSIONS IN BIOTITE-HORNBLENDE 

QUARTZ MONZONITE 

Small inclusions of silicated marble, calc-silicate 

hornfels, and tactite are scattered through a dark facies 

of the biotite-hornblende quartz monzonite. These inclusions cannot have come from the adjacent white 

quartzite but may have been carried upward by the 

quartz monzonite magma from the gray marble and calcsilicate rock formations. One of the inclusions is the 

site of the Garnet Dike tungsten mine. 

DIORITE SILLS AND DIKES 

Dark fine-grained diorite sills are present between the 

lower and upper members of the calc-silicate rock formation and within a calc-silicate hornfels member of 

the schist formation; a dike of similar rock cuts across 

the northernmost exposure of the gray marble and calcsilicate rock formations. These dikes and sills have 

been involved in the deformation of the enclosing sedimentary rocks and are doubtless older than any of the 

plutonic rocks. 

STRUCTURE 

The distribution of formations and the attitudes and 

top directions of beds indicate that the strata in the 

roof pendant have been complexly folded and thrust 

faulted. Three styles of folds were distinguished in 

the pendant, and their sequence established from the · 

order of superimposition of folds of .one style on another. The three generations of folds are designated 

first fold, second fold, and third fold. 

The gross distribution of formations results chiefly 

from the first deformation when the largest folds in the 

pendant, an overturned anticline and companion syncline, were formed. Later folding has deformed these 
STRATIGRAPHY, STRUCTURE, DINKEY CREEK ROOF PENDANT, SIERRA NEVADA, CALIFORNIA B5 

first folds, but the original attitude of their axial surfaces was probably very close to the present average 

attitude of those surfaces; their average strike is a little 

east of north, and their average dip is about 45° W. 

The large first folds are not obvious on the geologic map 

(pl. 1), mostly because related axial-plane faults complicate the structure, and glacial till obscures large parts 

of the structural pattern. The distribution of formations and bedding attitudes in the white quartzite 

clearly define the major first folds, however, and they 

are shown on the block diagram (pl. 1). The white 

quartzite formation is right-side-up along the northwest edge of the pendant, overturned in the middle part 

(just west of the schist), and right-side-up in the southeast part. In the north part of the pendant, the anticlinical hinge of the first fold is shown by the pattern of 

the biotite-andalusite hornfels, which wraps around the 

gray marble and the calc-silicate rock formations. The 

faulted hinge of the syncline is shown by the white 

quartzite, which wraps around the thin-bedded schist 

and quartzite formation in the south-central part of the 

pendant. 

The axial beds of both the anticline and the syncline 

have been sheared out by thrust faults parallel with the 

axial surfaces and with bedding. The fault along the 

axial surface of the anticline is necessary 'to explain the 

absence of the calc-silicate rock formation from the 

northwestern limb of the anticline in the north part 

of the pendant and the absence of this formation and 

the underlying gray marble farther southwest along the 

projected trace of the axial surface. In the north end 

of the pendant, this fault must lie between the gray 

marble of the core and the biotite-andalusite hornfels 

of the northwestern limb of the anticline; farther southwest it probably follows the southeastern boundary of 

the bioti-te-anclalusite hornfels on this northwestern 

limb (pl. 1). The fault along the axial surface of the 

syncline is required to explain the termina:tion, clowndip, of the three marble and calc hornfels beds in the 

schist formation against the white quartzite. A fault is 

also required in the eastern limb of the anticline between the white quartzite and the biotite-andalusite 

hornfels formations to explain the anomalous thinness 

of the overturned white quartzite west of the Rainbow 

tungsten mine. The faults have been folded with the 

first-generation folds and are believed to have developed during the later stages of first folding as an expression of extreme strain. 

Complexes of minor folds t hat reflect the larger folds 

are common. First folds have tighly appressed limbs 

and simple hinges (fig. 3). Most minor first folds that 

were observed are of about the same scale as those shown 

in figure 3, but larger folds with amplitudes in the order 

796-523 0 - 66 - 2 

of a few hundred feet are indicated by hinges and reversals in the top directions of beds. Less ductile beds 

generally have the same stratigraphic thicknessess 

everywhere in a fold, but more ductile beds have behaved plastically and thicken and thin irregularlygenerally they are thicker in the apexes of folds and 

thinner on the limbs. First folds are like the composite 

folds of similar habit of Hills ( 1963, p. 234) and the 

quasi-flexural folds of Donath and Parker (1964, p. 

59-60). 

Major second-generation folds have substantially 

smaller amplitudes than the principal first folds and 

affect the gross distribution of formations correspondingly less than the first-generation structures. The 

axial surface of the first-generation syncline, for example, is only slightly deformed where crossed by the 

larger second folds. The axes and traces of axial surfaces of three second-generation folds are shown on the 

geologic map and block diagram (pl. 1) . Minor secondgeneration folds have steep to vertical axial surfaces 

that strike about N. 20° W.; axes generally plunge 

10°-25° northward, but steeper northward plunges have 

been observed, and gentle southward plunges occur in 

the southeast tip of the pendant. Second-generation 

folds are generally open and have simple hinges (figs. 4 

and 5). They have the characteristics of folds formed 

by flexural slip or flexural flow (Donath and Parker, 

1964, p. 51-55). Deformation of first-generation structural features by second folds is reflected in the gross 

distribution of the formations and in the relations of 

minor first and second folds to each other. 

Third-generation folds were observed only locally in 

the roof pendant and are all minor. In places they are 

abundant and can be seen superimposed on first- and 

second-generation folds (fig. 6). Third-generation 

folds are open and have vertical axial planes that strike 

about N. 60° W.; fold axes plunge northwest. They are 

most conspicuous in the extreme northwest corner of the 

roof pendant. 

Other structural elements in the roof pendant are 

cleavages and lineations (pl. 1). Cleavage occurs 

locally in association with all of the fold generations 

but is most commonly associated with first folds (fig. 3). 

Generally, it parallels or fans about axial surfaces. 

Much of the original cleavage was lost during metamorphism of the strata to the hornblende hornfels facies. 

Such cleavage as remains is pervasive and results from 

mineral orientation rather than from closely spaced 

fracture surfaces. In the biotite-andalusite hornfels, 

porphyroblasts of andalusite locally accentuate cleavage 

surfaces. Lineations other than minor folds in bedding 

are streaks of biotite and intersections of bedding and 

cleavage. All the lineations parallel fold axes. 
B6 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

FIGURE 3.- Typical first folds with cleavage parallel to axial surfaces. A (upper), In thin-bedded 

schist and quartzite. B (lower), In thin-bedded marble and hornfels. 
STRATWRAPHY, STRUCTURE, DINKEY CREEK ROOF PENDANT, SIERRA NEVADA, CALIFORNIA B7 

FIGURE 5.-Second fold in thin-bedded marble and hornfels. 

Minor fold in limb (below hammer) may be either a ·first 

or second fold. 

STRUCTURE DIAGRAMS 

Collective diagrams for structural elements of the 

metamorphic rocks, plotted in lower hemisphere projections on an equal-area net, are as follows: Poles to 

bedding, poles to first-fold axial surfaces, first-fold 

axes, second- and third-fold axes, and lineations (fig. 

7). The diagram showing poles to bedding (fig. 7 A) 

indicates considerable dispersion about a rectalinear 

fold axis .that plunges 25° N. 20° W. If small areas 

are removed at the two ends of the pendant, where field 

observations indicate the fold pattern is a little different 

than in the main body of the pendant, the dispersion 

around this axis is substantially reduced (fig. SB) . For 

convenience, we designate the south tip of the pendant, 

subarea 1 ; the main body of the pendant, subarea 2; and 

a small part of the north end, subarea 3 (fig. S) . 

In subarea 1, poles to beds define a fold axis that 

plunges about 15 o S. 25 o E. (fig. SA). Lineations in 

this subarea, mostly streaks of biotite on bedding surfaces, generally coincide with the fold axis defined by 

bedding attitudes. In the main part of the pendant, 

subarea 2, second-fold axes indicate a maximum (fig. 

SO) that coincides with the fold axis normal to the 

girdle of poles to bedding (fig. SB) and also with a fold 

axis normal to the partial girdle of poles to first-fold 

axial surfaces (fig. SD). These relations show that this 

statistically defined rectilinear axis results from second 

folding; hence, we designate it {3 2 • First-fold axes in 

subarea 2 are rather widely scattered but generally 

plunge to the northwest (fig. SF). In subarea 3, poles 

to bedding poorly define a fold axis that plunges westnorthwest (ifig. SG). In this subarea both second- and 

third-fold axes are widely scattered. 

INITIAL ORIENTATION OF THE FOLDS 

The third folds are still in their original positions. 

Because third folds are too small for the structural elements of the second folds to have been significantly 

disturbed during their formation, we conclude that the 

second folds also are very close to their original positions. Field observations and the structural diagrams 

show that third-fold axial surfaces are near vertical and 

strike about N. 60° W. and tha:t the fold axes plunge 

variably to the northwest. Second-fold axial surfaces 

also are near vertical and strike N. 20° W. In the main 

part of the pendant (subareas 2 and 3), second-fold 

axes plunge about 25° NW., but in the southeast end 

(subarea 1) they plunge 10-15° SE. 

Because second folds are of considerable size, significant parts of the structural elements of the first folds 

must have been rotated during the formation of the 

second folds. The mechanism of second folding was by 

flexural slip or flexural flow; and the axis of second 
B8 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

FIGURE 6.-Later folds crossing earlier folds in thin-bedded schist and quartzite. A (upper), 

Third fold (along pencil) cr ossing first folds . B (lower) , Third folds superimposed on second 

folds. Second folds run from lower right to upper left; third folds run directly across 

photograph. 
• 

STRATIGRAPHY, STRUCTURE, DINKEY CRE·EK ROOF PENDANT, SIERRA NEVADA, CALIFORNIA B9 

A B c 

D E 

Diagram Structural element Points 

A____________________ Poles to bedding__________________________________________ 429 

B ____________________ Poles to axial surface of first folds___________________________ 70 

C _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ First-fold axes__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 49 

D ____________________ Second- and third-fold axes_________________________________ 101 

E__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Lineations (mineral streaks, bedding-cleavage intersection)______ 38 

FIGURE 7.-Collective diagrams of structural elements in the Dinkey Creek roof pendant. 

Contours (percent per 1-percent area) 

0.23-2.5-5 

1. 4-4. 3-10 

2-10 

1-1Q-20 

2.7-1Q-18 
BlO SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

.. 

. . 

A 

+ 

B c D 

• /32 

++ . 0 ... . . + I 

++ + I 

+ / / / / / 

~0 0/o _, / 

~()~ _, 

- ------

- . 

E F G 

FIGURE 8.-Subareas with a single cylindrical fold axis of bedding in the Dinkey Creek roof pendant. 
STRA'l'IGRAPHY, S'l'RUCTURE, D-INKEY CRE,EK ROOF PENDANT, SIERRA NEVADA, CALIFORNIA Bl] 

folding, Pz = Bz kinematic axis (Weiss, 1959, p. 92). 

When the second folds were formed, the structural elements of the first folds were rotated in planes or cones 

around f3z, depending on whether they were perpendicular or oblique to {32 • On structural diagrams they 

would plot respectively along a great circle and along 

small circles with {32 at the center of the circles. 

: Coincidence of the two girdles formed by poles to 

first-fold axial surfaces (Fig. 8D) and poles to beds (fig. 

SB) shows that the beds and axial surfaces of first folds 

are almost parallel and that therefore, first folds are isoclinal-a conclusion in agreement with field observations of nearly parallel bedding attitudes in right-sideup and overturned limbs of major first folds and of 

tightly appressed limbs of minor first folds. 

Both of these girdles contain a principal maximum 

that plunges 40° S. 85° E. A question to consider is 

whether the maximum in the two girdles indicates the 

position of the poles to beds and first-fold axial surfaces 

prior to second folding, or whether it merely marks a 

preferred position into which the beds and first-fold 

axial surfaces were rotated during second folding. 

Ftield observations of minor second folds indicate that 

t~e second folding was not isoclinal; therefore, any maxi urn of poles to beds or to first-fold axial surfaces 

f rmed during second folding should occur in pairs 

a the ends of a partial girdle (Ramsay, 1964, fig. 10, p. 

9). The fact that no other maximum in either girdle 

a proaches the magnitude of the principal maximum 

s ows.that the principal maximum does not result from 

second folding and must represent the position of the 

poles to beds and first-fold axial surfaces prior to second 

folding. 

If we look now at the diagram of first-fold axes 

(fig. SF), it is evident that they do not lie on a small 

circle with a center at {32 ; so, their present distribution 

could not have been caused by simple flexure folding 

about /32 of first folds that had a very uniform axial 

orientation. ·The three maximums in the diagram lie 

close to, although not precisely along, a great circle 

whose pole plunges 40° N. 85° E.-very close to the maximum in the girdle of poles to bedding and to first-fold 

axial surfaces. Conceivably the distribution of the 

maximums could result from folds earlier than the presently recognized first folds, but as we observed no folds 

earlier than the first folds, it seems morelikely that the 

spread of maximums results from primary undulations 

of the first-fold axes in their axial surface. The axes 

scattered away from the great circle that passes through 

the three maximums probably result from rotation 

around {32 • According to this interpretation first-fold 

axial surfaces initially had a strike of N. 5° E. and a 

dip of 50° W. The fold axes pitched to the northwest 

in the axial surface at 30° to 80° (corresponding to 

plunges of 20° to 55°). 

EXTENT AND CAUSE OF THE DEFORMATIONS 

The deformed strata of the Dinkey Creek roof pendant provide no way to determine whether the successive 

deformations closely followed one another or were 

widely separated in time. Regional relations suggest, 

howev~er, that the deformations were widely separated 

in time and that each fold system- represents a distinct 

period of widespread regional deformation. 

Two causes of the deformations can be envisaged: 

( 1) The folds were caused by the emplacement of bordering plutons and are consequently limited to the pendant, and (2) the folds were caused by regional forces 

and are part of a regional pattern. 

If the structural features in the metamorphic rocks 

were caused by the emplacement of bordering plutons, 

geometrical and temporal relations must exist between 

specific plutons and the different generations of folds. 

If all the folds weDe formed during one complex episode, 

the only intrusive in an orientation that could have produced the folds is the hornblende-biotite granodiorite 

("Dinkey Creek" type). If the folds were formed during separate episodes, the most likely pairings are between the hornblende-biotite granodiorite ("Dinkey 

Creek" type) and first folds, between porphyritic biotite 

granite and second folds, and between the garnet-bearing biotite granite and third folds. The basis for these 

EXPLANATION OF FIGURE 8 

Subarea Diagram Structural element Points Contours (percent per 1-percent area) 

1 A__________________ Poles to bedding ___________________________ --------------- •Lineations ______________________________________________ _ 24 4.2-8.3-12.5 

9 Uncontoured 2 B- _- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Poles to bedding _____________________________________ -- __ _ C__________________ Second-fold axes __________________________________________ _ 364 0.35-4-5-10 

48 2. 1-20 D __________________ Poles to axial surfaces of first folds _________________________ _ 58 1. 7-10-15 E __________________ Poles to axial surfaces of second folds _______________________ _ 29 3.2-1Q-33.3 F ___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ First-fold axes ___________________________________________ _ 33 3.3-1Q-20 3 G ________________ . _ Poleg to bedding _________________________________________ _ 45 2. 2-6.6 

+Third-fold axes ___________________________________ ----_-- 6 Uncontoured • Second-fold axes _________________________________________ _ 12 Uncontoured 
B12 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

pairings is that these plutons could have been emplaced 

in the proper sequence, and their contacts with the pendant are subparallel with the fold systems with which 

they are paired. The fact that the fold systems appear 

to be regular and continuous throughout the pendant 

and to be truncated at its margins is a strong argument 

against relating the folds to the emplacement of the bordering plutons. The map pattern in the north part of 

the pendant suggests that second folds a.re truncated 

by the granodiorite ("Dinkey Creek" type). If so, both 

the first and second folds must be older than either the 

granodiorite or the porphyritic biotite granite. 

The case for the folds having been caused by intrusion 

of the bordering plutons is thus very weak, but emplacement of plutons probably caused at least minor modifications of the structural features in the margins and at the 

ends of the pendant. In particular, the emplacement of 

plutons could have caused the structural variations in 

subareas 1 and 3 at the south and north ends of the 

pendant. 

Comparison of structural features in the Dinkey 

Creek roof pendant with features determined in other 

roof pendants and in the southern part of the western 

metamorphic belt (fig. 1) suggests considerable correspondence of fold patterns. In the Log Cabin 

pendant, which lies directly west of Mono Lake, Kistler 

has identified, in Paleozoic rocks, folds similar in style 

and with axial surfaces parallel to the first folds of the 

Dinkey Creek pendant (fig. 9). In the northern extension of the Ritter Range pendant, Kistler has identified, 

in Paleozoic strata, first folds with axial surfaces that 

strike N. 10° W. and dip 45° W., second folds with 

vertical axial surfaces that strike N. 30° W., and third 

folds with vertical axial surfaces that strike N. 50° W. 

In this pendant, volcanic strata with a rubidiumstrontium whole-rock age of 260 million years (C. E. 

Hedge, written commun., 1962) show no evidence of the 

first deformation and unconformably overlie Pennsylvanian-Permian( n strata that were folded during the 

first deformation. These data suggest that the first 

deformation in the Ritter Range pendant must be 

Permian. 

In the Goddard pendant we have identified first folds 

with nearly vertical axial surfaces that strike N. 25° W., 

parallel with the strata and oblique to the length of 

the pendant, and second folds with vertical axial surfaces that strike N. 50° W., parallel with the long axis 

of the pendant. In this pendant, small plutons of 

alaskite and granodiorite were emplaced after the first 

folding and were deformed during the second folding. 

In the southern part of the western metamorphic belt, 

the principal folds in the Upper Jurassic strata have 

axial surfaces that strike N. 45° W., and dip steeply 

east. 

If the fold systems maintain their orientations ( specifically, the orientations of their axial surfaces) across 

the width of the Sierra Nevada at this general latitude, 

the first folds in the Dinkey Creek pendant may correspond to the first folds in the Log Cabin pendant and 

northern extension of the Ritter Range pendant; the 

second folds to the second folds in the northern extension of the Ritter Range pendant and to the first folds 

in the Goddard pendant; ·and the third folds to third 

folds in the Ritter Range pendant, to second folds in 

the Goddard pendant, and to the regional folds in the 

southern part of the western metamorphic belt. 

If we accept the correlation of the first deformation 

in the Dinkey Creek pendant with the first deformation in the Ritter Range pendant and the Permian age 

of the first deformation in the Ritter Range pendant, 

the strata in the Dinkey Creek pendant must be of Paleozoic age. In support of this conclusion is close resemblance of the strata of the Dinkey Crook pendant to 

strata of early Paleozoic age in the Mount Morrison 

pendant of the eastern Sierra Nevada (Rinehart and 

others, 1959). A Paleozoic age is in conflict with the 

tentative assignment of these strata to the Mesozoic, possibly the T_riassic, made by Bateman and others ( 1963, 

p. D6) on the basis of lithologic correlation with the 

Boyden Cave pendant, 25 miles to the southeast, and 

with the Mineral King pendant, 60 miles to the southeast. Fossils of Triassic or Jurassic age have been collected from the Boyden Cave pendant (Moore and 

Dodge, 1962), and fossils of Late Triassic age have been 

collected from the Mineral King pendant (Knopf and 

Thelan, 1905; Durrell, 1940; Christensen, 1963). However, the facts that the strata in the Boyden Cave 

pendant, though lithologically similar to the strata in 

the Dinkey Creek pendant, do not seem to be stratig· 

raphically equivalent and that the Mineral King 

pendant contains volcanic rocks and wackes in addition 

to miogeosynclinal strata leaves room for doubting the 

validity of the correlation. The strata in the Dinkey 

Creek pendant are lithologically unlike eugeosynclinal 

volcanic and sedimentary strata of Early Jurassic age 

in the Ritter Range pendant or of Late Jurassic age in 

the western metamorphic belt and are not likely to be 

Jurassic. 

SUMMARY AND CONCLUSIONS 

The Dinkey Creek roof pendant is composed of five 

metamorphosed sedimentary rock formations that have 

had the following history : 

1. Depositions of calcareous, arenaceous, and argillaceous strata in a shallow marine environment. 
STRATIGRAPHY, .STRUCTURE, D·INKEY CREEK ROOF PENDANT, SIERRA NEVADA, CALIFORNIA Bl3 

I 

I • I 

I 

~ I 

/ 

/ 

/ 

A 

~ + I 

I 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

' ', 

' 

~ 

~ 

EXPLANATION 

• Fold axes 

"-:._,) 

~ 

Poles to axial 

surfaces 

0 

Poles to beds 

-B 

EXPLANATION 

0 

Dinkey Creek 

pendant 

Log Cabin 

roof pendant 

FIGURE 9.-A, Diagram of maximums of points representing first-fold axes, first-fold axial surfaces, and 

bedding in subarea 2, Dinkey Creek pendant. Note that the points abstracted from figures 8B, 8D, and 

8F repreS'ent in projection an isoclinal fold with axial surface that strikes about north and dips about 

45° W. Fold axes pitch at various angles to the northwest in the axial surface. B, Diagram showing 

maximums of first-fold axes and poles to axial surfaces in the Log Oabin roof pendant and in subarea 2 

of the Dinkey Creek roof pendant. The interpreted original orientation of first-fold axial surfaces in 

the Dinkey Creek pendant closely approximates the meaS'Ured attitude of first-fold axial surfaces in 

the Log Cabin roof pendant, which has not suffered major subsequent deformation. Note that in both 

pendants first-fold axes pitch at various angles in the first-fold axial surfaces. 

2. Isoclinal folding with axial surfaces that strike N. 5° 

E. and dip 50° W. Thrust faulting following or 

contemporaneous with late stages of folding. 

3. Open folding around vertical axial surfaces that 

strike about N. 20° W. 

4. Minor folding around vertical axial surfaces that 

strike about N. 60° W. 

5. Intrusion of the plutonic rocks and contact metamorphism of the sedimentary rocks to hornfels. 

Comparison of the fold systems in the Dinkey Creek 

pendant with those of other pendants in the central 

Sierra Nevada suggests that the fold systems reflect 

regional deformations that were widely separated in 

time. The orientations of axial surfaces formed during each deformation seem to be remarkably constant 

over long distances. Such constancy may reflect deep 

burial of the strata at the time of folding with accompanying higher temperatures and greater pressures, 

which acted to reduce the contrast in structural competence of the different strata. If structural episodes can 

be correlated from roof pendant to roof pendant, age 

brackets can also be placed on strata that ·contain 

structural features formed during certain episodes. 

This technique would be especially useful as an aid to 

lithologic correlations in sparsely fossiliferous strata. 

However, much more detailed structural and stratigraphic work will be required before the validity of such 

correlations can be accepted without reservation. 
B14 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

REFERENCES CITED 

Bateman, P. C., Clark, L. C., Huber, N. K., Moore, J. G., and 

Rinehart, C. D., 1963, The Sierra Nevada batholith-a 

synthesis of recent work across the central part: U.S. Geol. 

Survey Pro1'. Paper 414-D, p. D1-D46. 

Christensen, M. N., 1963, Structure of metarmorphic rocks at 

Mineral King, California: California Univ. Pub. Geol. Sci., 

v. 42, no. 4, p. 159--198. 

Donath, F. A., and Parker, R. B., 1964, Folds and folding: Geol. 

Soc. America Bull., v. 75, no. 1, p. 4~62. 

Durrell, Cordell, 1940, Metamorphism in the southern Sierra 

Nevada northeast of Visalia, California: California Univ. 

Pub. Geol. Sci., v. 25, no.1, p. 1-117. 

Fyfe, W. S., Turner, F. J., and Verhoogen, Jean, 1958, Metamorphic reactions and metamorphic facies : Geol. Soc. 

America Mem. 73, 259 p. 

Hills, E. S., 1963, Elements of structural geology: New York, 

John Wiley 'and Sons, Inc., 483 p. 

Knopf, Adolph, and Thelan, Paul, 1905, Sketch of the geology 

of the Mineral King district, California: California Univ. 

Dept. Geology Bull., v. 4, p. 227-262. 

Krauskopf, K. B., 1953, Tungsten deposits of Madera, FreSIIlo, 

and Tulare Counties, California: California Div. Mines 

Spec. Rept. 35, 83 p. 

Moore, J. G., and Dodge, F. C., 1962, Mesozoic rage of metamorphic rocks in the Kings River area, southern Sierra 

Nevada, California, in Geological Survey Research 1962: 

U.S. Geol. Survey Prof. Paper 450--B, p. B19--B21. 

Ramsay, J. G., 1964, The uses and limitations of beta-diagrams 

and pi-diagram in the geometrical analysis of folds: Geol. 

Soc. London Quart. Jour., v. 120, pt. 3, no. 479, p. 4~54. 

Rinehart, C. D., Ross, D. G., and Huber, N. K., 1959, Paleozoic 

and Mesozoic fossils in a thick stratigraphic section in 

the eastern Sierra Nevada, California : Geol. Soc. America 

Bull., v. 70, no. 7, p. 941-945. 

Weiss, L. E., 1959, Geometry of superposed folding: Geol. Soc. 

America Bull., v. 70, p. 91-106.