Paleozoic and Mesozoic Deformations 

in the Central Sierra Nevada, 

California
Paleozoic and Mesozoic Deformations 

in the Central Sierra Nevada, 

California

By WARREN J. NOKLEBERG and RONALD W. K1STLER

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1145

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1980
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECIL D. ANDRUS, Secretary

GEOLOGICAL SURVEY 

H. William Menard, Director

Library of Congress Cataloging in Publication Data

Nokleberg, Warren J

Paleozoic and Mesozoic deformations in the 

central Sierra Nevada, California.

(Geological Survey professional paper ; 11*1-5)

Bibliography: p. 22-24.

Supt. of Docs, no.: I 19.16:11^5

1. Rock deformation--Sierra Nevada Mountains. 

2. Geology--Sierra Nevada Mountains. I. Kistler, 

Ronald Wayne, 1931- joint author. II. Title. 

III. Series: United States. Geological Survey. 

Professional paper ; 11*4-5. 

QE6CA-.N61J. 551.8 '0979^ 80-607011

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

Washington, D.C. 20402

Stock number 024-001-03293-7
CONTENTS

Page

Abstract______________________________________ 1

Introduction ______________________________________ 1

Problems of Sierra Nevada deformational history-_____________ 2

Paleozoic deformations ________________________________ 2

Devonian or Mississippian regional deformation ________ 2

Orientation of structures ____________________________ 2

Style of deformation _____________________________ 5

Timing of deformation and regional correlations ______ 5

Permian and Triassic uplift, erosion, and Andean-type

volcanism _____________________________________ 6

Mesozoic deformations _______________________________ 7

Areal extent-___________________________ 7

Triassic regional deformation of high-country roof pendants 7

Orientation and style of structures __________________ 7

Timing of deformation and regional correlations ____ 9

Early and Middle Jurassic regional deformation _-______ 9

Orientation and style of structures ________________ 9

Timing of deformation and regional correlations ______ 11

Page

Mesozoic deformations Continued

Nevadan orogeny in the western metamorphic belt-------- 11

Orientation and style of structures ________________ 12

Timing of deformation and regional correlations ______ 14

Jurassic and Early Cretaceous regional deformations of

high-country roof pendants _______________________ 14

Orientation and style of structures _____-______---___ 14

Timing of deformation and regional correlations ______ 15

Cretaceous regional deformation ________________________ 17

Orientation and style of structures __________________ 17

Timing of deformation and regional structures __ 18 

Continuing problems __________ ___________________________ 18

Episodic or continuous deformation?---------------_ - 18

Role of granitic intrusions _____________-_--___-----_--_- 19

Conjugate folds _____________________ -- -------_----_ 19

Conclusions ___________________-________----- ------------- 19

Acknowledgments ____-_____________________________ _ 20

References cited _______________-_ ___-_-------------------- 20

FIGURE

ILLUSTRATIONS

Page

Generalized geologic map of the central Sierra Nevada __________--_____--___-_ __-_______-_____---__-------_ 3

Structural diagrams for areas deformed during the Devonian or Mississippian period along north-south trends ______ 6

Structural diagrams for three high-Sierra Nevada roof pendants ____________________________________-___-------- 8

Structural diagrams for parts of the Calaveras Formation ____________________________-----_-------_----__-------- 10

Structural diagrams for areas of the western metamorphic belt ________________________________-_-----__--------- 13

Structural diagram of poles to bedding---_______________________________________-----_-_------------_------- 14

Structural diagrams for high-country roof pendants deformed probably during Jurassic orogenies __ _____________ 16

Structural diagrams for high-country roof pendants and areas of the western metamorphic belt ____________________ 18

TABLES

Page

TABLE 1. Regional deformations recorded in roof pendants and wallrocks of the central Sierra Nevada______- --------------- 4

2. Data for figure 2 _____________________________________________________________________________________ 7

3. Data for figure 3 _____________________________________________________________ 8

4. Data for figure 4 __________________________________________________________________________ 11

5. Data for figure 5 ------____________---__--___________--______-________----___------__________________________ 12

6. Data sources for figure 6 ______________________________________________________ _________________________ 14

7. Data for figure 7 ________________________________________ ___________________ 18

8. Data for figure 8 ________________________________________________ ________ _ __ 20

III

PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE 

CENTRAL SIERRA NEVADA, CALIFORNIA

By WARREN J. NOKLEBERG and RONALD W. KISTLER

ABSTRACT

Analysis of structural and stratigraphic data indicates that several periods of regional deformation, consisting of combined folding, 

faulting, cataclasis, and regional metamorphism, occurred throughout the central Sierra Nevada during Paleozoic and Mesozoic time. 

The oldest regional deformation occurred alono northward trends 

during the Devonian and Mississippian periods in most roof pendants containing lower Paleozoic metasedimentary rocks at the center 

and along the crest of the range. This deformation is expressed in 

some roof pendants by an angular unconformity separating older 

thrice-deformed from younger twice-deformed Paleozoic metasedimentary rocks.

The first Mesozoic deformation, which consisted of uplift and erosion and was accompanied by the onset of Andean-type volcanism 

during the Permian and Triassic, is expressed by an angular unconformity in several roof pendants from the Saddlebag Lake to the 

Mount Morrison areas. This unconformity is defined by Permian and 

Triassic andesitic to rhyolitic metavolcanic rocks unconformably 

overlying more intensely deformed Pennsylvanian, Permian(?), and 

older metasedimentary rocks. A later regional deformation occurred 

during the Triassic along N. 20°-30° W. trends in Permian and 

Triassic metavolcanic rocks of the Saddlebag Lake and Mount Dana 

roof pendants, in upper Paleozoic rocks of the Pine Creek roof pendant, and in the Calaveras Formation of the western metamorphic 

belt; the roof pendants are crosscut by Upper Triassic granitic rocks 

of the Lee Vining intrusive epoch. A still later period of Early and 

Middle Jurassic regional deformation occurred along N. 30C-60° E. 

trends in upper Paleozoic rocks of the Calaveras Formation of the 

western metamorphic belt. A further period of deformation was the 

Late Jurassic Nevadan orogeny, which occurred along N. 20°-40° W. 

trends in Upper Jurassic rocks of the western metamorphic belt that 

are crosscut by Upper Jurassic granitic rocks of the Yosemite intrusive epoch. Structures of similar age occur in intensely deformed 

oceanic-lithospheric and syntectonic plutonic rocks of the lower 

Kings River area, in Jurassic metavolcanic rocks of the Ritter Range 

roof pendant, and in Triassic metasedimentary rocks of the Mineral 

King roof pendant. The final Mesozoic deformation occurred along N. 

50°-80° W. trends in both high-country roof pendants and the lower 

Kings River area; structures of this generation are crosscut by relatively undeformed Upper Cretaceous granitic rocks of the Cathedral 

Range intrusive epoch.

INTRODUCTION

Considerable controversy persists over the deformational history of intruded wallrocks of the Sierra 

Nevada in California. Three major interpretations are 

current: (1) a complex faulted synclinorium with main

structural grain resulting from the Late Jurassic 

Nevadan orogeny (Bateman and others, 1963; 

Bateman and Clark, 1974); (2) accretion of Mesozoic 

country rocks onto the west side of the range against 

an Andean-type volcanic arc (Hamilton, 1969, 1978; 

Schweickert and Cowan, 1975; Davis and others, 1978; 

Schweickert, 1978); and (3) an anticlinorium that 

formed as a result of multiple deformations (Kistler 

and others, 1971). In this report we test these interpretations by examining geologic structures in the^ different roof pendants and in areas of the western 

metamorphic belt that have already been studied in 

detail. From rock ages and the style and orientation of 

regional structures, we envision successive generations of deformations, infer their causes, and 

bracket their durations.

Previous reports that discussed the tectonics of the 

range include studies of the Alpine County area 

(Parker, 1961), the Mono Craters quadrangle (Kistler, 

1966a, b), the Dinkey Creek roof pendant (Kistler and 

Bateman, 1966), and the Mount Morrison roof pendant 

(Russell and Nokleberg, 1974, 1977). Valuable new information on the structure, stratigraphy, and rock ages 

of roof pendants and areas of the western metamorphic 

belt is available from recent detailed studies of the 

Strawberry mine roof pendant (Nokleberg, 1970a, b), 

the Saddlebag Lake roof pendant (Brook, 1972, 1974, 

1977), the Ritter Range roof pendant (Kistler, 1966a, b; 

Fiske and Tobisch, 1978), the Boyden Cave roof pendant (Girty, 1977a, b), the lower Kings River area 

(Saleeby, 1974, 1975, 1976, 1978; Nokleberg, 1975; 

Saleeby and others, 1978), the Merced River area (W. 

J. Nokleberg, unpub. data, 1978), the Oakhurst roof 

pendant (Russell and Cebull, 1977), and the western 

metamorphic belt (Baird, 1962; Best, 1963; Wetzel and 

Nokleberg, 1976; Schweickert and others, 1977; 

Schweickert, 1978). We have also made use of structural data from the geologic maps by Taliaferro and 

Solari (1948), Clark (1954, 1964, 1970), Eric, Stromquist, and Swinney (1955), Mannion (1960), Christensen (1963), Bateman (1965), Huber and Rinehart 

(1965), and Duffield and Sharp (1975).

1
PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

PROBLEMS OF SIERRA NEVADA 

DEFORMATIONAL HISTORY

Besides discussing the controversy over the general 

structure of the country rocks, in this report we present 

critical evidence on the following questions regarding 

the deformational history of the area and the age 

groups of regional rocks: (1) Have multiple regional 

deformations, widely spaced in time, generated in successively older sequences of rocks progressively more 

superposed structures (Kistler, 1966a; Kistler and 

Bateman, 1966; Nokleberg, 1970a, b; Brook, 1972, 

1974, 1977; Nokleberg, 1975; Wetzel and Nokleberg, 

1976; Russell and Nokleberg, 1977)? (2) Does the 

Mount Morrison roof pendant comprise a thick homoclinal sequence on the east limb of a synclinorium 

(Rinehart and Ross, 1964), or a series of isoclinally 

folded units (Russell and Nokleberg, 1977)? (3) Are the 

Antler, Sonoman, and other orogenies of the Great 

Basin recorded in country rocks of the Sierra Nevada 

(Speed and Kistler, 1977)? (4) Were some multiple deformations merely conjugate folds formed during a 

single event (Tobisch and Fiske, 1976)? (5) Did a single 

principal Mesozoic deformation, the Late Jurassic 

Nevadan orogeny (Bateman and others, 1963; 

Bateman and Clark, 1974), occur, or several superposed deformations with subparallel northwestward 

trends (Russell and Nokleberg, 1977), or simply one 

continuing deformation over a long period (Hamilton, 

1978)? (6) Do major angular unconformities exist that 

separate older more highly deformed from younger less 

deformed rocks (Morgan and Rankin, 1972; Brook and 

others, 1974)?

PALEOZOIC DEFORMATIONS

Significant evidence exists for two Paleozoic regional 

deformations in roof pendants along the center and 

crest of the Sierra Nevada. A Devonian or 

Mississippian regional deformation, possibly the Antler orogeny, occurs in Ordovician and Silurian(?) 

metasedimentary rocks of the Mount Morrison roof 

pendant (Russell and Nokleberg, 1977), and similar 

structures are present in lower Paleozoic rocks of the 

Log Cabin mine, Bishop Creek, and Dinkey Creek roof 

pendants over a distance of 112 km (fig. 1). A Late 

Permian regional deformation consisting of uplift, erosion, and onset of Andean-type volcanism is expressed 

by an angular unconformity exposed from the 

Saddlebag Lake roof pendant in the north to the Mount 

Morrison roof pendant in the south, over a distance of 

about 70 km (fig. 1). This unconformity marks a major 

change in sedimentation from Paleozoic miogeosynclinal sedimentary rocks named the Lewis sequence 

(Kistler, 1966a) to lower and middle Mesozoic metavolcanic rocks named the Koip and Dana sequences, respectively (Kistler, 1966a). The Paleozoic as well as 

Mesozoic deformations that we define for the central 

Sierra Nevada are listed below (table 1) by age of deformation, rock age, and locality, along with the data 

sources. Our table is based on the ideas of Kistler 

(1966a), Kistler and Bateman (1966), and Russell and 

Nokleberg (1977), who suggested that the similarities 

in structural style and orientation of distant roof pendants and of areas of the western metamorphic belt reflect regional deformations that occurred over widely 

separated intervals.

DEVONIAN OR MISSISSIPPIAN REGIONAL DEFORMATION

ORIENTATION OF STRUCTURES

The accompanying diagrams (figs. 2-8) show lowerhemisphere equal-area projections of structural data 

on regional deformations in the Sierra Nevada; data 

sources are listed either in the figures or in their corresponding tables (tables 2-8). The diagrams showing 

structures formed during the Devonian and 

Mississippian regional deformation also give the average attitudes of axial planes and schistosities (figs. 2 A, 

2D, 2H). We take the term "schistosity" as synonymous with "axial-plane cleavage." These diagrams of 

axial planes and schistosities are useful for the correlation of structures between isolated areas because the 

axial surfaces of folds tend to be initially planar in 

spite of preexisting variations in the fold orientation of 

bedding or foliation. Later deformation of an earlier 

generation of folds tended to create a simpler structure 

in the axial planes than in other elements, such as the 

fold axes or bedding (Weiss, 1959). The Devonian or 

Mississippian deformational structures are the oldest 

known in the central Sierra Nevada and consequently 

were most likely be to reoriented during later regional 

deformations. In each area studied, however, the dominant orientations of axial planes and schistosities are 

remarkably uniform and show average strikes of from 

N. 10° W. to north and nearly vertical dips. In the Dinkey Creek roof pendant (fig. 2H) axial planes have 

been rotated along a great circle that defines a 

northwest-plunging fold axis; we attribute this warping and rotation to refolding during a later Mesozoic 

deformation.

The fold axes and parallel lineations resulting from 

the Devonian or Mississippian regional deformation 

(figs. 25, 2E, 21) show a less preferred orientation 

than the corresponding axial planes because the orientations of fold axes are controlled in part by folding of 

the preexisting-surface orientation and may vary considerably, especially where earlier folds exist (Weiss, 

1959). The maxima of fold axes, which plunge gently
119°

~7 Saddlebag Leke 

r pendant

-7V *

Log Cabin mine 

pendant

June Leke 

pendent

Ritter Range 

pendant EXPLANATION

Mt M

pen

Granitic rocks (Mesozoic)

WESTERN SIERRA NEVADA

greenschist, and serpen

tinite (Mesozoic)

Calaveras Formation (Paleozoic)

EASTERN SIERRA NEVADA 

ish

p

Eugeosynclinal metavolcanic and

metasedimentary rocks Mt Goddard 

A. pendant

quence (Lower Jurassic)

Lower Kings 

River pendent Miogeosynclinal metasedimentary

rocks (upper Paleozoic)

B

p

Miogeosynclinal metasedimentary 

rocks (lower Paleozoic)

Metamorphic rocks of unknown 

age

10 20 30 40 KILOMETERS

I

Contact

____ 0 10 20 MILES

FIGURE 1. Generalized geologic map of central Sierra Nevada, California, showing location of roof pendants and areas in western metamorphic bel

are omitted.
PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

TABLE 1.—Regional deformations recorded in roof pendants and wallrocks of the central Sierra Nevada

Age of deformation, including average strike of fold axial planes, rock types, and age of younger rocks for each area

Area

Bishop Creek 

(Bateman, 1965)

Log Cabin mine 

(Kistler, 1966)

Dinkey Creek 

(Kistler and Bateman, 

1966)

Mount Morrison 

(Russell and Nokleberg, 

1974, 1977)

Saddlebag Lake 

(Brook, 1972, 1974, 

1977)

Northern Ritter Range 

(Kistler, 1966a)

Pine Creek 

(Bateman, 1965)

Calaveras Formation 

Stanislaus River 

(Baird, 1962)

Calaveras Formation 

Merced River 

(W. J. Nokleberg, 

unpub. data, 1977) 

Boy den Cave (Girty, 

1977)

Strawberry mine 

(Nokleberg, 1970a, b)

Western metamorphic 

belt, central and 

western blocks 

(Wetzel and Nokleberg, 

1976) 

Lower Kings River area 

(Nokleberg, 1975)

Mineral King 

(Christensen, 1963)

Mount Dana 

(Kistler, 1966a, b; 

Russell, 1976)

Ritter Range 

(Kistler, 1966a, b; 

Huber and Rinehart, 

1965; Fiske and 

Tobisch, 1978)

Devonian or Mississippian 

deformation

N. 

Metasedimentary rocks, 

Ordovician (?) and 

Silurian (?) 

N. 

Metasedimentary rocks, 

Ordovician (?) and 

Silurian (?)

N. 5° E. 

Metasedimentary rocks, 

Paleozoic (?)

N. 8° W. 

Metasedimentary rocks, 

Ordovician and Silurian (?)

N. 8° W. 

Metasedimentary rocks, 

Ordovician (?) and 

Silurian (?)

Triassic deformation

Angular unconformity

N. 23° W. 

Metavolcanic rocks 

Permian and Triassic 

isochron

N. 25° W. 

Metavolcanic rocks 

Permian and Triassic 

isochron

N. 22° W. 

Metasedimentary rocks 

Pennsylvanian (?) and 

Permian (?)

N.-250 W. 

Metavolcanic rocks 

Permian and Triassic 

isochron

Early and Middle 

Jurassic deformation

bordered by 

bordered by

bordered by

N. 60° E. 

Slate, Pennsylvanian (?) 

and Permian (?)

N. 40° E. 

Slate, Pennsylvanian (?) 

and Permian (?)

N. 60° E. 

Metasedimentary rocks, 

Upper Triassic and 

Lower Jurassic

Northeast 

Metasedimentary rocks, 

Lower Jurassic (?)

Angular unconformity

Late Jurassic Nevadan 

orogeny

Upper Triassic granite 

Upper Triassic granite

N. 25° W. 

Same rocks

N. 30° W. 

Metasedimentary rocks 

Mesozoic metavolcanic 

rocks

Upper Triassic granite

N. 25° W. 

Same rocks

N. 30° W. 

Same rocks

N. 20° W. 

Same rocks

N. 30° W. 

Metavolcanic rocks, 

Lower Cretaceous 

isochron

N. 20°-40° W. 

Slates and greenschists 

Upper Jurassic

N. 30° W. 

Deformed gabbros 

Middle Jurassic 

(Saleeby, 1974)

N. 30° W. 

Metasedimentary rocks 

Upper Triassic fossils

N. 30° W. 

Metavolcanic rocks 

(lower part of Dana 

sequence) 

Jurassic isochron

N. 30° W. 

Metavolcanic rocks 

Permian, Triassic, and 

Lower Jurassic isochrons 

and Pb-U zircon ages

Cretaceous deformation

N. 60° W. 

Same rocks

N. 60° W. 

Same rocks

N. 61° W. 

Same rocks

N. 50° W. 

Same rocks

N. 60° W. 

Same rocks

N. 60° W. 

Same rocks

Encircled by Lower 

Cretaceous granite

N. 65° W. 

Metavolcanic rocks (upper 

part of Dana sequence) 

Lower Cretaceous 

isochron

N. 70° W. 

Metavolcanic rocks 

Lower Cretaceous isochron 

and Pb-U zircon ages

Note: Ages of roof pendants or wallrocks, when known with some certainty, are given. For areas in which younger generations of structures are absent, age of adjacent granitic rocks is 

given.

north or south within the axial planes in all roof pendants, indicate either a first or near-first deformation of 

these rocks. The double gently plunging maxima in the

Mount Morrison and Log Cabin mine roof pendants 

(figs. 2B, 2 E) may indicate superposition of these 

structures over broad northeast-striking folds. In the
PALEOZOIC DEFORMATIONS

Dinkey Creek roof pendant the distribution of fold axes 

along the axial plane may represent a component of 

slip folding, or primary undulations in the axial surfaces of fold axes (Kistler and Bateman, 1966).

The orientations of poles to bedding in these rocks 

(figs. 2 C, 2F, 2 G, 2 J) yield less information than the 

fold axes and axial planes because the bedding was 

usually rotated into various attitudes during a single 

regional deformation, and later deformation caused 

considerably more scatter (Weiss, 1959). However, the 

Log Cabin mine and Dinkey Creek roof pendants (figs. 

2 F, 2 J) show a relatively simple distribution of poles 

to bedding along a partial great circle that defines a 

subhorizontal fold axis plunging either north or south. 

Coincidence of this axis with the concentration of Devonian or Mississippian fold axes in the respective roof 

pendants (compare fig. 2F with 2E, 21 with 2 J) indicates that during this deformation the bedding was rotated into major folds of the same orientation as minor 

folds, and also that a strong component of flexural folding is present (Weiss, 1959). The Bishop Creek roof 

pendant (fig 2G) shows a distribution of poles to bedding along great circles that define a subhorizontal 

/3-axis, gently plunging 8° to azimuth 008°—evidence 

of the first deformation of these rocks. The data on the 

Bishop Creek roof pendant are from the Mount Goddard geologic quadrangle, mapped by Bateman (1965). 

In the Mount Morrison roof pendant (fig. 2 C) poles to 

bedding are distributed along partial great-circle girdles that define fold axes plunging gently to the northwest or southeast; the coincidence of these axes with 

later Mesozoic fold axes indicates subsequent deformation of the rocks.

STYLE OF DEFORMATION

Isoclinal folding during the Devonian or 

Mississippian regional deformation is shown by the 

parallel maxima of poles to bedding and poles to axial 

planes and schistosities (fig. 2), which indicate that fold 

limbs were parellel to axial planes; most of the areas 

shown in the structural diagrams (fig. 2) also possess 

isoclinal folds. Major thrust faults parallel to the 

major-fold axial planes, which were reported for the 

Mount Morrison, Dinkey Creek, and Log Cabin mine 

roof pendants (Kistler and Bateman, 1966; W. J. Nokleberg, unpub. data, 1976; Russell and Nokleberg, 

1977), indicate that thrusting was contemporaneous 

with folding. In the Log Cabin mine roof pendant the 

axial plane thrusts dip as gently as 20° W. and strike 

N. 5° E. The gentle to moderate westward dips of axial 

planes and thrust faults in the Log Cabin mine and 

Dinkey Creek roof pendants and the presence of overturned asymmetric folds indicate tectonic transport 

from west to east.

Regional metamorphism coinciding with deformation and causing formation of cataclasites, axial-plane 

schistosities, and lineations was reported by most of 

the above authors. Regional metamorphism of the 

greenschist facies is indicated in the Mount Morrison, 

Log Cabin mine, and Dinkey Creek roof pendants by 

the occurrence of such index minerals as epidote, chlorite, andalusite, and actinolite in appropriate-composition rocks that indicates recrystallization at relatively 

low temperature and shallow depth. In most roof pendants this regional metamorphism has been overprinted 

by one or more episodes of contact metamorphism during emplacement of granitic rocks. Most roof pendants 

are completely recrystallized to the hornblendehornfels facies on their edges, whereas the interiors of 

some large roof pendants still exhibit prior regionalgrade metamorphism.

TIMING OF DEFORMATION AND REGIONAL 

CORRELATIONS

The age of the Devonian or Mississippian regional 

deformation is best established in the fossiliferous 

Mount Morrison roof pendant, where metamorphosed 

miogeosynclinal rocks are subdivided into an Ordovician McGee Mountain block on the east, a central Silurian(?) Convict Lake block, and a Pennsylvanian and 

Permian(?) Bloody Mountain block on the west 

(Rinehart and Ross, 1964). A stratigraphic thickness of 

9,600 m was established for what Rinehart and Ross 

(1964) interpreted as a homoclinal sequence, progressively younger to the west. Three generations of isoclinal folds, faults, and related structures were later recognized by Russell and Nokleberg (1977), who estimated the actual thickness to be 4,500 m or less. 

North-striking structures of the first generation occur 

only in the Ordovician and Silurian(?) rocks, whereas 

the general occurrence of structures of all later generations in blocks of all rock ages limits the time of first 

deformation to the Devonian or Mississippian (table 1). 

An angular unconformity, now defined by the LaurelConvict fault, separates Ordovician and Silurian(?) 

from Pennsylvanian and Permian(?) rocks (Rinehart 

and Ross, 1964; Russell and Nokleberg, 1977), and 

older thrice-deformed from younger rocks containing 

only the last two generations of structures.

To the south the Bishop Creek roof pendants contain 

north-striking Devonian or Mississippian folds (fig. 

2 G) and Ordovician or Silurian graptolites, recently 

found in the Coyote Flat area by J. N. Moore (oral 

commun., 1976). The similarity between rock types, 

ages, and structures in the Mount Morrison and Bishop 

Creek roof pendants is strong evidence of codeformation during the Devonian or Mississippian. The similarity between rock types and structures in the Mount 

Morrison roof pendant and in the Log Cabin mine and 

Dinkey Creek roof pendants, as well as the observation
PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

POLES TO AXIAL PLANES FOLD AXES AND 

AND SCHISTOSITIES LINEATIONS POLES TO BEDDING

MOUNT MORRISON ROOF PENDANT

Ordovician and Silurian (?) matasadimentary rocks (Russall 

and Noklebarg, 1977)

LOG CABIN MINE ROOF PENDANT

Lowar Palaozoic metasedimantary rocks (Kistlar, 1966a, b)

BISHOP CREEK ROOF PENDANT

Lower Paleozoic metasedimentary 

rocks (Bataman, 1965)

DINKEY CREEK ROOF PENDANT

Lowar Paleozoic metasedimentary 

rocks (Kistlar and Bataman, 

1966)

H

FIGURE 2.—Structural diagrams for areas deformed along northward trends during the Devonian or Mississippian. Data are 

from Ordovician and Silurian(?) or lower Paleozoic rocks of high Sierra Nevada roof pendants. Dashed great circles, 

average maximum attitude of axial planes, schistosities, or bedding; solid great circles, girdles of poles to axial planes 

and schistosities, or to bedding; b, major-fold axes, denned as poles to girdles. Contour data are listed in table 2.

that this was their first intense deformation, indicates 

that these roof pendants were codeformed during the 

Devonian or Mississippian, coincident with the Antler 

orogeny in the Great Basin (Russell and Nokleberg, 

1977). The structures in the central Sierra Nevada and 

in the Antler orogenic belt are all due to compression 

and include folds, thrust faults, lineations, and schistosities. Asymmetric folds and thrust faults in the Log 

Cabin mine and Dinkey Creek roof pendants indicate 

tectonic transport from west to east, analogous to the

Antler orogeny, in which Cambrian and Devonian 

eugeosynclinal sedimentary rocks were thrust eastward over miogeosynclinal sedimentary rocks of similar age along the Roberts Mountain thrust during the 

Late Devonian (Burchfiel and Davis, 1972).

PERMIAN AND TRIASSIC UPLIFT, EROSION, AND 

ANDEAN-TYPE VOLCANISM

The Devonian or Mississippian regional deformation 

is separated from later deformations by a period of,
MESOZOIC DEFORMATIONS

TABLE l.-Data for figure 2

Diagram Points Contours 

(percent per 1 percent area)

A

B

C

D

E

F

G

H

I

J

K

L

M

144

98

176

23

29

172

178

58

33

364

75

75

1055

0.7,3.5,7,10

1,5.1,10,15.3

0.6,2,6,10

4.4,5, 10,20

3.3, 10, 20

0.6,5,10

0.6,1.1,2.2,4.5

1.7, 10,15

3.3,10,20

0.35,4,5, 10

1,5,20,40

1,4,8, 10

1,3,5

successively: deposition; uplift, erosion, and tilting; 

and, finally, onset of Andean-type volcanism. These 

events are recorded by an angular unconformity between a sequence of lower or upper Paleozoic 

metasedimentary rocks and of Permian and Triassic 

metavolcanic and volcanic-derived sedimentary rocks 

named the Koip sequence (Kistler, 1966a). This unconformity occurs along a 75-km stretch of the Sierra 

Nevada crest that includes the Saddlebag Lake roof 

pendant (Brook, 1972, 1977), the Mount Dana roof 

pendant (Russell, 1976), the northern part of the Ritter 

area of the Ritter Range roof pendant (Kistler, 1966a), 

and the Mount Morrison roof pendant (Russell and 

Nokleberg, 1977). Interpretation of the contact between these two sequences as an angular unconformity 

rather than a fault is discussed by Morgan and Rankin 

(1972) and Brook, Nokleberg, and Kistler (1974).

The Permian and Triassic age of uplift, tilting, and 

erosion is indicated by Pennsylvanian and Permian(?) 

rocks of the Mount Morrison roof pendant, which are 

the youngest rocks underlying the unconformity; and 

by Permian and Triassic rocks of the Saddlebag Lake 

and Ritter Range areas, which are the oldest rocks 

overlying the unconformity. A Permian age for this 

angular unconformity coincides with the Sonoman 

orogeny and related Golconda thrusting in the Great 

Basin (Silberling and Roberts, 1962; Speed, 1971). In 

the area where the Koip sequence overlies Ordovician 

and Silurian(?) metasedimentary rocks, uplift and erosion could have occurred at any time between the Silurian^) and Triassic. In any case, volcanism began in 

the Permian and Triassic with formation of the Koip 

sequence, which gave a Rb-Sr whole-rock isochron of 

240 m.y. (Kistler, 1966a; Brook, 1972, 1977). Although 

development of the unconformity has been tentatively 

correlated with the Sonoman orogeny, continuation of 

the Golconda thrust has not yet been found in the central Sierra Nevada. Our knowledge of this unconformity is important because the contact represents a 

major change in the stratigraphy and structure of the 

wallrocks that occurred immediately before the early 

stages of Andean-type volcanism and of emplacement 

of the magmas that formed the massive Sierra Nevada 

batholith.

MESOZOIC DEFORMATIONS

AREAL EXTENT

Geologic evidence is found for several Mesozoic regional deformations in the central Sierra Nevada (table 1). The first and oldest Mesozoic deformation ocv 

curred along N. 20°-40°W. trends during the Triassic 

and is defined by the folding and faulting of Permian 

and Triassic metavolcanic rocks of the Saddlebag Lake 

and northern Ritter Range roof pendants, and of 

Pennsylvanian(?) and Permian(?) metasedimentary 

rocks of the Pine Creek roof pendant; and by tilting or 

folding of the eastern part of the Calaveras Formation 

in the western metamorphic belt. A Jurassic regional 

deformation occurred along N. 30°-60° E. trends in the 

Calaveras Formation and is superposed on older 

northwest-striking structures. A later Mesozoic regional deformation is the classic Nevadan orogeny of 

Late Jurassic age that deformed the western metamorphic belt and roof pendants in the batholith (table 1). 

The Nevadan orogeny is preserved in the western 

metamorphic belt as a fault-fold system, striking N. 

20°-40° W., that contains large- and small-scale faults, 

asymmetric folds, and zones of melange. The Nevadan 

orogeny can be identified with certainty only in the 

Mineral King, Ritter Range, Mount Dana, and Boyden 

Cave roof pendants, although many other roof pendants, including the Mount Morrison, Saddlebag Lake, 

and Dinkey Creek roof pendants, contain structures of 

similar trend and style that can only be dated as ranging from Triassic to Early Cretaceous. A still-later 

Mesozoic regional deformation occurred along N. 50°- 

80°W. trends during the Early or early Late Cretaceous 

in several widely separated roof pendants and in areas 

of the western metamorphic belt that definitely include 

the Strawberry mine and Ritter Range roof pendants, 

in the lower Kings River area, and probably in the 

Mount Morrison, Dinkey Creek, Saddlebag Lake, and 

Bishop Creek roof pendants.

TRIASSIC REGIONAL DEFORMATION OF 

HIGH-COUNTRY ROOF PENDANTS

ORIENTATION AND STYLE OF STRUCTURES

An intense deformation along N. 20°-30° W. trends 

is recorded in the Koip and Lewis sequences of the 

Saddlebag Lake and northern Ritter Range roof pendants (Kistler, 1966a; Brook, 1972, 1977), and in upper
PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

Paleozoic(?) metasedimentary rocks of the Pine Creek 

roof pendant (fig. 1, table 1). The diagrams of poles to 

axial planes and schistosities for this deformation (fig. 

3, table 3) show average strikes of N. 20°-30° W. and 

vertical dips (dashed great circle, fig. 3 A; dashed great 

circle 1, fig. 3D). In the northern Hitter Range roof 

pendant (figs. 3 D-3 F) the partial spread of poles to 

axial planes along a great circle, and a concentration of 

axial planes along N. 60°-70° W. trends (dashed great

circle 2), are attributed to a later early Late Cretaceous 

deformation. In the Saddlebag Lake roof pendant (figs. 

3A-3C) fold axes and lineations formed during the 

Triassic deformation plunge moderately to steeply 

northwest within the N. 20°-30° W. axial planes (fig. 

35). In the northern Ritter Range roof pendant, fold 

axes of this and a later deformation, which are plotted 

together, plunge primarily along N. 60° W.-striking 

axial planes (fig. 3E). Kistler (1966a) showed that the

POLES TO AXIAL PLANES 

AND SCHISTOSITIES

FOLD AXES AND 

LINEATIONS POLES TO BEDDING

SADDLEBAG LAKE ROOF PENDANT

Permian and Triassic metavolcanic 

rocks (Brook, 1972, 1974, 

1977)

NORTHERN RITTER RANGE ROOF PENDANT

Permian and Triassic metavolcanic 

rocks (Kistler, 1966a, b)

PINE CREEK ROOF PENDANT

Upper Paleozoic metasedimentary 

rocks (Bateman, 1965)

TABLE 3.-Data for figure 3

Diagram Points Contours 

(percent per 1 percent area)

A

B

C

D

E

F

G

117

41

29

81

158

128

58

1,5,8,10

5, 13,17

7, 17,25

1.2,6,9,12

0.62,5,10

0.8,2,4,6,8

1.7,3.4,7,10

FIGURE 3.—Structural diagrams for three high-Sierra Nevada roof pendants deformed during the Triassic Period along N. 20°-30° W. trends.

See figure 2 for explanation. Contour data as shown.
MESOZOIC DEFORMATIONS

later formed fold axes are superposed on the limbs of N. 

20°-30° W.-striking folds of Triassic age (dashed great 

circle, fig. 3E).

The diagrams of poles to bedding (figs. 3 C, 3 F, 3 G) 

show the rotation of bedding to steep dips, with average strikes of N. 20°-30° W. in all three areas. In the 

northern Ritter Range roof pendant a secondary 

maximum of bedding occurs along N. 60° W. strikes, 

with a near-vertical dip (dashed great circle 2, fig. 3 F) 

that also reflects later deformation. In the Saddlebag 

Lake roof pendant a weak distribution of bedding poles 

occurs along a great circle that defines a /3-axis plunging moderately northwest, with a 20°-30° W.-striking 

axial plane (fig. 3 C) parallel to the maxima of fold axes 

and lineations (fig. 3B). Upper Paleozoic metasedimentary rocks of the Pine Creek roof pendant (fig. 3 G) 

contain large folds, with axial planes striking N. 20°- 

30° W., and steep dips, as shown on the Mount Goddard 

geologic quadrangle map (Bateman, 1965). The diagram of poles to bedding for this area (fig. 3 G) also 

shows rotation of beds into steep dips, with N. 20°-30° 

W. strikes.

In both the Saddlebag Lake and northern Ritter 

Range roof pendants the Triassic deformation of the 

Koip and Lewis sequences was an intense event that 

gave rise to isoclinal folds, parallel faults, and regional 

metamorphism. Isoclinal folding is shown by field evidence, by parallel maxima of poles to bedding and to 

axial planes (fig. 3), and by cross sections of folds in the 

Saddlebag Lake roof pendant (Brook, 1972, 1977). 

Major high-angle faults paralleling the axial planes 

are shown on geologic maps of the two areas (Kistler, 

1966b; Brook, 1972, 1977). The upright nature of folds 

and the near-vertical dip of associated faults indicate 

mainly compression during this deformation and little 

tectonic transport of one plate over another. In both 

roof pendants, regional metamorphism coincided with 

deformation and included formation of cataclasites, 

axial-plane schistosities, and lineations (Kistler, 

1966a, b; Brook, 1972, 1977). Regional metamorphism 

occurred under conditions of the greenschist facies 

with the crystallization of such index minerals as andalusite, chlorite, and epidote (Kerrick, 1960; Brook, 

1972). In both roof pendants, regional metamorphism 

was overprinted by two periods of contact metamorphism associated with emplacement of Late Triassic 

and Late Cretaceous granitic rocks (Kistler, 1966a).

TIMING OF DEFORMATION AND REGIONAL 

CORRELATIONS

The Koip sequence is dated Permian and Triassic 

(240 m.y.) by a Rb-Sr whole-rock isochron (Kistler, 

1966a; Brook, 1972, R. W. Kistler, unpub. data, 1977). 

Structures in the sequence are intruded by Late Triassic granitic rocks of the Lee Vining intrusive epoch 

(Evernden and Kistler, 1970); these relations bracket 

the intense deformation of the Koip and older sequences as Early and Middle Triassic. The age of this 

deformation can also be determined from the Pine 

Creek roof pendant, where N. 20°-30° W.-striking 

structures in Pennsylvanian(?) and Permian(?) 

metasedimentary rocks are crosscut by relatively undeformed Late Triassic (210 m.y. old) granitic rocks of 

the Lee Vining intrusive epoch; this relation restricts 

the deformation to the Late Permian or Triassic.

In the Calaveras Formation of the western 

metamorphic belt is evidence for two pre-Nevadan deformations, the earlier of which occurred along N. 

20°-40° W. trends and is expressed by a northwesttrending form surface, dipping moderately northeast, 

upon which later folds are superposed (Baird, 1962; W. 

J. Nokleberg, unpub. data, 1976). This earlier deformation is possibly the same as the Triassic deformation of 

the high-country roof pendants. The eastern part of the 

Calaveras Formation contains abundant metaquartzite and meta(quartz-rich)siltstone, designated 

chert by Clark (1964), that were designated the Shoo 

Fly Formation(?) (fig. 1) by Schweickert (1978). In the 

following discussion the Shoo Fly(?) is included in the 

Calaveras Formation.

EARLY AND MIDDLE JURASSIC REGIONAL DEFORMATION

ORIENTATION AND STYLE OF STRUCTURES

The upper Paleozoic Calaveras Formation, which is 

intensely deformed along N. 30°-50° E. trends in a 

large area from the Stanislaus to the Merced Rivers 

(fig. 1, table 1), exhibits melange, broken formation, 

cataclasites, and isoclinal to open folds (Wetzel and 

Nokleberg, 1976). These structures, superposed on 

older northwest-striking structures (Baird, 1962; W. J. 

Nokleberg, unpub. data, 1976), occur in slate, 

metasiltstone, marble, and metabasalt commonly included in the Calaveras Formation but possibly containing rocks of a wide range of ages and origins 

(Clark, 1964). The melange character of the Calaveras 

Formation along the Stanislaus and Tuolumne Rivers 

has also been observed by Schweikert and Cowan 

(1975). The diagrams of poles to axial planes and 

schistosities for this deformation (fig. 4, table 4) show 

an average orientation of N. 30°-60° E. over a wide 

terrain (figs. 4 A, 4 D, 4 G, 4 J). In structures of the 

greenschist east of the Melones fault on the Stanislaus 

River (fig. 4D) the poles to axial planes are distributed 

along a great circle, with a secondary maximum of 

axial planes and schistosities trending N. 30° W. and 

dipping steeply west that is due to the later Late 

Jurassic Nevadan orogeny (Baird, 1962). Fold axes and
10 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

POLES TO AXIAL PLANES 

ANDSCHISTOSITIES

FOLD AXES AND 

LINEATIONS POLESTO BEDDING

CALAVERAS FORMATION

Stanislaus River, upper Paleozoic 

(Baird, 1962; Worthington, 

1978)

GREENSCHIST

Stanislaus River, upper Paleozoic 

metavolcanic rocks (Baird, 

1962)

CALAVERAS FORMATION

Merced River, geologic marker 

upper Paleozoic (W. J. Nokleberg, unpub. data, 1978)

CALAVERAS FORMATION

Merced River, cement quarry 

upper Paleozoic (W. J. Nokleberg, unpub. data, 1978)

BOYDEN CAVE ROOF PENDANT

Lower Juressic metasedimentary 

rocks (Girty, 1977e, b)

FIGURE 4.—Structural diagrams for parts of the Calaveras Formation in the western metamorphic belt deformed 

during the Late Triassic and Middle Jurassic along N. 30°-60° E. trends. See figure 2 for explanation. Contour 

data in table 4.

lineations show a remarkable parallel orientation, 

with maxima plunging generally 30°-80° at azimuths 

between 030° and 060° (figs. 4B, 4E, 4H, 4K). In all

areas the diagrams of poles to bedding show a distinct 

girdle that defines /3-axes plunging moderately to 

steeply northeast, parallel to the concentrations of fold
MESOZOIC DEFORMATIONS 11

TABLE 4.-Data for figure 4

Diagram Points Contours 

(percent per 1 percent area)

A

B

C

D

E

F

G

H

I

J

K

L

M

N

125

117

170

71

133

178

42

58

157

41

35

34

10

42

1,4,8,12,16

1,5,10,20

1,2,4,6,8, 12

1,2,8,12

1,4,8, 12,16

1,2,3,5,6,8

1,4,8,12

1,8,16

0.2,2,6

1,5,10

1,5,15

1,2,4,8

1,5,7

1,5,10

axes and lineations in each area (figs. 4 C, 4F, 41, 4L); 

this feature indicates that the major, like the minor, 

folds plunge moderately to the northeast at nearly 

right angles to strike of the batholith and range (Wetzel and Nokleberg, 1976).

The style of structures varies from the Stanislaus 

River in the north to the Merced River in the south, 

where cataclasis is much less intense and folds much 

more frequent than along the Stanislaus River. The 

folds along the Merced River are strongly asymmetric, 

probably because of superposition over the older 

northwest-trending form surface (W. J. Nokleberg, unpub. data, 1976). This deformation is associated with 

regional metamorphism that included formation of 

schistosities, lineations, and partly recrystallized 

cataclasites; recrystallization occurred under conditions of the greenschist facies (W. J. Nokleberg, unpub. 

data, 1976).

The Boyden Cave roof pendant, along the west side of 

the batholith (fig. 1), contains an older generation of 

structures remarkably similar in style, geometry, and 

orientation to those in the Calaveras Formation. 

Cataclastic calc-silicate hornfels is intensely deformed 

along N. 60° E. trends (table 1), with open to isoclinal 

folds, schistosities, and melange (Girty, 1977a, b). The 

fold-axial planes strike N. 60° E., with fold axes and 

lineations plunging moderately at azimuth 060° (fig. 

4 M). Bedding in this unit is rotated around a /3-axis 

that plunges moderately at azimuth 090° (fig. 4 N) and 

nearly coincides with the fold axes (fig. 4 N}.

Metasedimentary rocks of the Strawberry mine roof 

pendant, in the center of the batholith (fig. 1), contain 

the oldest generation of structures, consisting of major 

northeast-trending folds and associated minor isoclinal 

folds (Nokleberg, 1970a, b; W. J. Nokleberg, unpub. 

data, 1977). The orientation and style of these structures are similar to those of older structures in the

Boyden Cave roof pendant. These metasedimentary 

rocks of the Strawberry mine roof pendant, of probable 

Early Jurassic age, are similar to Upper Triassic and 

Lower Jurassic metasedimentary rocks of the Boyden 

Cave and Mineral King roof pendants, which compose 

the Kings sequence of Bateman and Clark (1974).

TIMING OF DEFORMATION AND REGIONAL 

CORRELATIONS

A maximum age for the Early and Middle Jurassic 

regional deformation is indicated by: (1) probable Middle Triassic deformation of the upper Paleozoic 

Calaveras Formation; (2) Lower Jurassic fossils (Jones 

and Moore, 1973) in cataclasites of the Boyden Cave 

roof pendant (Girty, 1977a, b); and (3) probable Lower 

Jurassic metasedimentary rocks of the Strawberry 

mine roof pendant (W. J. Nokleberg, unpub. data, 

1977). A minimum age for this deformation is indicated by Late Jurassic metamorphic rocks of the western 

metamorphic belt, which were codeformed with the 

Calaveras Formation during the Late Jurassic Nevadan orogeny (Wetzel and Nokleberg, 1976). Thus the 

deformation of the Calaveras Formation and of the 

Boyden Cave roof pendant along N. 30°-60° E. trends is 

bracketed as Early or Middle Jurassic.

A significant aspect of Sierra Nevada tectonics is the 

divergence of northeast-trending structures in the 

Calaveras Formation from the northwest-trending 

batholith. These northeast-trending folds, shear zones, 

and schistosities may have formed during northwestsoutheast compression associated with left-lateral 

shear displacement along the western Sierra Nevada 

during the Middle Jurassic, as suggested by Silver and 

Anderson (1974) and Kistler and Peterman (1978). 

This displacement is defined by displacement of both 

Precambrian crystalline terranes and Paleozoic depositional trends from southeastern California to Sonora, 

Mexico (Silver and Anderson, 1974).

NEVADAN OROGENY IN THE WESTERN METAMORPHIC 

BELT

Deformational structures resulting from the Late 

Jurassic Nevadan orogeny in the western metamorphic 

belt consist of the Foothills fault system, which comprises the Melones and Bear Mountain faults, numerous smaller faults and shear zones, melange zones 

(Duffield and Sharp, 1975), and large folds that, according to Clark (1960, 1964), have essentially horizontal 

axes and wide homoclinal belts, with axial planes 

striking northwest and dipping steeply east, parallel to 

the Foothills fault system and apparently older than 

the faulting. Measurements of top directions in 

Mesozoic rocks of the western metamorphic belt, which
12 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

show that 70 percent of the beds face east, define 

thereby the west limb of a large synclinorium 

(Bateman and Clark, 1974).

The Melones and Bear Mountain faults divide the 

western metamorphic belt into three blocks: (1) an 

eastern block consisting chiefly of the upper Paleozoic 

Calaveras Formation, and (2) central and (3) western 

blocks consisting chiefly of serpentinized peridotite, 

greenschist (predominantly metabasalt), and slate 

with subordinate graywacke in an older-to-younger 

age sequence. The assemblage in the central and western blocks was considered oceanic lithosphere by Wetzel and Nokleberg (1976), accreted island-arc volcanic 

and sedimentary rocks by Schweikert and Cowan 

(1975) and Moores (1970), and (or) dismembered 

ophiolite sequences representing slabs of oceanic crust 

on which island-arc volcanic rocks were deposited 

(Bateman and Clark, 1974).

ORIENTATION AND STYLE OF STRUCTURES

A recent structural and tectonic analysis of the western metamorphic belt (Wetzel and Nokleberg, 1976) 

shows that the Late Jurassic Nevadan orogeny produced a fault-fold system, striking N. 20°-40° W. and 

dipping steeply east, that contains asymmetric folds, 

melange zones, and cataclasites. The major and minor 

folds plunge steeply to the southeast, parallel to lineations in the fault and melange zones. Movement on this 

fault-fold system consisted mostly of right-lateral 

strike-slip with a smaller component of reverse dipslip. The diagrams of poles to axial planes and schistosities for this deformation (fig. 5, table 5) show almost uniform N. 20°-40° W. strikes and steep eastward 

dips parallel to strike and dip of the Foothills fault 

system (figs. 5 A, 5D, 5G, 5 J, 5 M); these orientations 

also occur in the discontinuous extension of the belt 

to the southeast along the lower Kings River area 

(Nokleberg, 1975). The parallelism of folds, faults, 

schistosities, shear zones, melanges, and cataclasites 

indicates that these structures represent a single 

generation of codeformed structures resulting from a 

common stress field. The diagrams for the Calaveras 

Formation in the Angels Camp to Sonora area (figs. 

5 A-5 C) and for large serpentinite in the lower Kings 

River area (figs. 5 M, 5 AD show rotation of the older 

axial planes and schistosities into orientations parallel 

to the Foothills fault-fold system. The diagrams of fold 

axes and lineations (figs. 5B, 5E, 5H, 5K, 5AO show 

well-defined maxima plunging steeply to the east in 

the northern part of the belt and to the southeast in the 

central and southern parts. The east-plunging 

maximum of fold axes and lineations in the Angels 

Camp to Sonora area (fig. 5B) represents rotated Late 

Triassic and Middle Jurassic fold axes.

TABLE 5. -Data for figure 5

Diagram

A

B

C

D

E

F

G

H

I

J

K

L

M

N

Points

121

32

35

59

30

20

35

52

450

95

42

63

78

56

Contours

(percent per 1 percent area)

1,2,4,6,8

1,2,4,6

1,2,6,8

1,2,5,10

1,2,5,10

1,2,5

2.9, 6, 10, 14

2,7, 12, 17

0.4, 2, 4, 6

1,2,6,10

1,2,6,18

1,2,4,6

1,2,4

1,4,12

The diagrams of poles to bedding (figs. 5 C, 5 F, 57, 

5L) show well-defined great circles that in turn define 

a single /3-axis of major folding in each area. The 

/3-axes generally plunge steeply to moderately east or 

southeast and mostly coincide with the concentrations 

of minor-fold axes and lineations. The moderate to 

steep plunges of major- and minor-fold axes indicate 

few, if any, folds with subhorizontal axes in the western metamorphic belt. The southeastward plunge of 

fold axes and the compressive nature of reverse faulting and folding indicate a combination of right-lateral 

strike-slip and reverse dip-slip movements in the 

Foothills fault-fold system (Wetzel and Nokleberg, 

1976). A component of right-lateral strike-slip motion 

is also indicated by the asymmetry of major folds, with 

longer east and shorter west limbs (Wetzel and Nokleberg, 1976), as shown on the California State Geologic 

Map, published by the California Division of Mines and 

Geology, and on geologic maps of the Angels Camp and 

Sonora quadrangles by Eric, Stromquist, and Swinney 

(1955).

The nature of folding from the Nevadan orogeny is 

also illustrated by a plot of poles to bedding with top 

directions for Mesozoic rocks of the western metamorphic belt (fig. 6, table 6), which shows: (1) a strong 

girdle of poles to beds that defines a single /3-axis 

plunging moderately southeast, (2) no distinct girdle of 

poles to bedding defining a subhorizontal axis, (3) beds 

in the core of folds facing toward the southeast, and (4) 

mainly isoclinal folding with opposing top directions on 

the limbs of folds.

Low-grade regional metamorphism coincided with 

folding, faulting, and cataclasis during the Nevadan 

orogeny. Throughout most of the central and western 

parts of the belt, pervasive greenschist facies recrystallization has occurred with formation of such diagnostic 

minerals as epidote, chlorite, albite, and actinolite
MESOZOIC DEFORMATIONS 13

POLES TO AXIAL PLANES 

ANDSCHISTOSITIES

FOLD AXES AND 

LINEATIONS POLES TO BEDDING

CALAVERAS FORMATION

Angels Camp and So nor a, upper 

Paleozoic (Eric and others, 

1955)

PENON BLANCO VOLCANICS

Same area,Triassic or Jurassic 

(Eric and others, 1955)

MARIPOSA FORMATION

Northwest of Mariposa, Upper 

Jurassic slate (Best, 1963)

LOWER KINGS RIVER ROOF PENDANT

Matasedimentary rocks Calaveras 

Formation(?), upper Paleozoic^) (Nokleberg, 1975)

LOWER KINGS RIVER ROOF PENDANT

Serpentinite, Permian and Triassic 

(Noklaberg, 1975)

FIGURE 5.—Structural diagrams for areas of the western metamorphic belt deformed during the Nevadan orogeny along N. 

20°-40° W. trends. See figure 2 for explanation. Contour data in table 5.

(Bateman and others, 1963; Clark, 1964; W. J. Nokleberg, unpub. data, 1976). Around some large Late 

Jurassic plutons, a higher facies formed. Along the

west margin of the Guadalupe igneous complex of Best 

(1963) south of the Merced River, syntectonic growth of 

almandine, cordierite, hornblende, and biotite in
14 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

TABLE 6.-Data sources for figure 6

Area Authors

River maps from Cosumnes to Merced

Rivers

Mesozoic wallrocks, Amador County 

Mesozoic wallrocks, San Andreas

quadrangle

Clark (1964)

Duffield and Sharp (1975) 

Clark (1970)

FIGURE 6.—Structural diagram of poles to bedding with top directions for Upper Jurassic country rocks of the western metamorphic belt. Solid arrow (-*•) represents pole to bed facing east. Open 

arrow ( >) represents pole to bed facing west or southwest. Open 

arrow with tail (—> ) represents pole to bed facing south. Arrows 

pointing toward center of diagram indicate upright beds; arrows 

pointing toward edge of net indicate overturned beds. See figure 2 

for explanation.

strongly foliated schist and cataclasites indicates recrystallization under conditions of the upper amphibolite facies (W. J. Nokleberg, unpub. data, 1976). Apparently this pluton intruded during the waning stages 

of the Nevadan orogeny and thereby formed a higher 

grade regional facies than elsewhere.

FIMING OF DEFORMATION AND REGIONAL 

CORRELATIONS

The Nevadan orogeny was a short-lived but extremely intense deformation that occurred in the Late 

Jurassic between the early Kimmeridgian and late 

Tithonian Stages and spanned probably less than 5 

m.y. (Bateman and Clark, 1974). This short timespan 

is denned by a Kimmeridgian age on the youngest deformed rocks of the central and western blocks, and by 

a Late Jurassic age on crosscutting granitic rocks of 

the Yosemite intrusive epoch (Evernden and Kistler, 

1970). The Guadalupe igneous complex of Best (1963), 

emplaced during the Yosemite intrusive epoch, 

crosscuts the western metamorphic belt nearly perpendicularly just west of Mariposa, Calif.

The foothills fault-fold system may represent a 

short-lived subduction zone. Schweikert and Cowan 

(1975) claimed that the faults are similar to those in 

the Franciscan Complex of Berkland and others (1972) 

that similarly juxtapose rocks having no apparent 

stratigraphic or deformational relations with one 

another. Wetzel and Nokleberg (1976) argued that the 

fault-fold system is not a subduction zone (1) because of 

the short-lived nature of the Nevadan orogeny and the 

extent of right-lateral strike-slip movement in the 

Foothills fault system, and (2) because the fault system 

crosscuts pre-Early Jurassic plutons and is in turn 

crosscut by Late Jurassic plutons (Evernden and Kistler, 1970). An alternative view is that the fault-fold 

system was the locus of telescoping and accreting of 

oceanic lithosphere onto the continental margin in response to the beginning of oblique subduction farther 

west (Wetzel and Nokleberg, 1976).

JURASSIC AND EARLY CRETACEOUS REGIONAL 

DEFORMATIONS OF HIGH-COUNTRY ROOF PENDANTS

At least one and perhaps several periods of intense 

folding, reverse faulting, cataclasis, and low-grade regional metamorphism along N. 20°-40° W. trends can 

be identified in many roof pendants containing 

Mesozoic metavolcanic or older rocks (fig. 1, table 1). 

These structures are usually superposed on northtrending structures in areas containing lower 

Paleozoic metasedimentary rocks. It is tempting to say 

that all structures with N. 20°-40° W. trends in the 

high-country roof pendants resulted from the Late 

Jurassic Nevadan orogeny; in other roof pendants, 

however, these structures could have been formed earlier, during the Mesozoic and perhaps the Triassic regional deformations.

ORIENTATION AND STYLE OF STRUCTURES

The Late Jurassic Nevadan orogeny can be identified 

with certainty only in the Ritter Range, Mineral King, 

Boyden Cave, and Mount Dana roof pendants. The diagrams of poles to axial planes and schistosities for this 

deformation (fig. 7, table 7) show average orientations 

of N. 20°-40° W. strikes with vertical dips (figs. 1 A, 

7 C, 1 T). Fold axes and lineations for the Mineral 

King and Boyden Cave roof pendants (figs. 7 D, 7 £7) 

plunge shallowly to steeply within the northweststriking axial planes. The diagrams of poles to bedding
MESOZOIC DEFORMATIONS 15

for three roof pendants (figs. IB, IE, 7V) show rotation of bedding into nearly vertical orientations, parallel to axial planes and schistosities. In the Ritter Range 

roof pendant, poles to bedding are rotated along a great 

circle and define an initial period of folding on a (3 r 

axis that plunges subhorizontally to the northwest (fig. 

IB). In the Boyden Cave roof pendant, poles to bedding 

(fig. 7 V) define two great circles that represent the 

limbs of Early and Middle Jurassic folds and that also 

define two (3-axes (fa and (32 , fig. 7 V) plunging 

moderately north and south in the N. 20° W.-striking 

axial plane. In the Mount Dana roof pendant, Jurassic 

metavolcanic rocks contain a prominent N. 25°-30° 

W.-striking schistosity and are rotated into N. 20°-30° 

W.-striking folds (Kistler, 1966a; Russell, 1976).

In the Mount Morrison roof pendant a similar 

Mesozoic deformation occurs; the diagrams of poles to 

axial planes and schistosities show N. 20°-40° W.- 

striking axial planes with steep dips (figs. IF, 7H, 

IK}. The diagrams of fold axes and lineations (figs. 

7 G, 71, 7 L) show these structures plunging within the 

axial planes, but with steeper plunges for older Ordovician and Silurian(?) metasedimentary rocks and subhorizontal plunges for younger rocks. The plunges of 

fold axes and lineations are steep in the older rocks 

because this folding occurred on the limbs of older folds 

owing to the Devonian and Mississippian regional deformation, whereas these plunges are subhorizontal in 

the younger rocks because the folds formed in undeformed subhorizontal strata. The diagram of poles to 

bedding for Pennsylvanian and Permian(?) metasedimentary rocks (fig. 7 J) shows a distribution of 

poles along a great circle that defines a /8-axis plunging 

gently at azimuth 330°, nearly coinciding with the 

maximum of fold axes and lineations.

A similar style and orientation of structures occur in 

lower Paleozoic rocks of the Dinkey Creek roof pendant 

(figs. 7M,7N,7O) and in Lower Jurassic(?) metasedimentary rocks of the Strawberry mine roof 

pendant (figs. 7P, 7 Q, 7R). In both places the metasedimentary rocks are folded around N. 20°-40° W.- 

striking axial planes with steep dips; both major-and 

minor-fold axes plunge moderately northwest or 

southeast. Structures of the N. 20°-40° W. trend are 

generally superposed on older north-trending structures in roof pendants containing lower Paleozoic 

rocks. In the Dinkey Creek roof pendant, poles to axial 

planes and schistosities of an older deformation are 

rotated around a /8-axis that plunges gently to the 

northwest (fig. 2 H). In the Strawberry mine roof pendant, metamorphosed shallow intrusive rocks of early 

Cretaceous age also contain N. 20°-40° W.-trending 

folds, faults, and schistosities (fig. 7S).

The N. 2d°-40° W.-trending structures are associated with regional metamorphism of the greenschist 

facies in many roof pendants, including: (1) Pennsylvanian and Permian(?) metasedimentary rocks and 

Mesozoic metavolcanic rocks of the Mount Morrison 

roof pendant (Russell and Nokleberg, 1977), (2) Upper 

Triassic metasedimentary rocks of the Mineral King 

roof pendant (Christensen, 1963), (3) Lower Jurassic 

metavolcanic rocks of the Ritter Range roof pendant 

(Huber and Rinehart, 1965), and (4) Jurassic metavolcanic rocks of the Mount Dana roof pendant (Russell,

1976).

TIMING OF DEFORMATION AND REGIONAL 

CORRELATIONS

A Middle and Late Jurassic age can be inferred for 

the deformation of only four high-country roof pendants. Crosscutting of the central part of the Ritter 

Range roof pendant, containing N. 20°-40° W.- 

trending structures and Early Jurassic marine fossils 

(Huber and Rinehart, 1965), by Early Cretaceous 

plutonic rocks (O. T. Tobishch and R. S. Fiske, personal 

commun., 1975) thereby brackets the deformation as 

Middle and Late Jurassic. Intrusion of the Mineral 

King and Boyden Cave roof pendants, containing similarly trending structures as well as Late Triassic and 

Early Jurassic marine fossils, by Early Cretaceous 

granitic rocks of the Huntington Lake intrusive epoch 

(Evernden and Kistler, 1970) thereby brackets the deformation as Jurassic. Crosscutting of Mesozoic 

metavolcanic rocks (probably Permian through Jurassic) of the Mount Morrison roof pendant by Late Cretaceous granitic rocks of the Cathedral Range intrusive epoch (Evernden and Kistler, 1970) thereby 

brackets the deformation as Jurassic through Cretaceous. In the Mount Dana roof pendant, metavolcanic 

rocks constituting the lower part of the Dana sequence 

have been dated as Jurassic, and those constituting the 

upper part as Early Cretaceous, by a Rb-Sr isochron (R. 

W. Kistler, unpub. data, 1977). The lower part of the 

Dana sequence, which contains both older 20°-30° W.- 

trending and younger N. 60° W.-trending structures, is 

unconformably overlain by the upper part, which contains only younger N. 60° W.-trending structures (Kistler, 1966a, b; Russell, 1976; R. W. Kistler, unpub. data,

1977). These data restrict the deformation along N. 

20°-30° W. trends to the Late Jurassic or earliest Cretaceous. In several roof pendants, superposition of the 

N. 20°-40° W.-trending structures on older Devonian 

and Mississippian structures (Dinkey Creek and 

Strawberry mine roof pendants) thereby sets the 

maximum age of deformation at middle Paleozoic. In 

the Strawberry mine roof pendant, Crosscutting of N. 

20°-40° W.-trending structures in Lower Cretaceous 

metavolcanic rocks by Late Cretaceous granitic rocks 

of the Cathedral Range intrusive epoch (Evernden and
16 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

POLES TO BEDDING

POLES TO AXIAL PLANES 

ANDSCHISTOSITIES

FOLD AXES AND 

LINEATIONS

RITTER RANGE ROOF PENDANT

Triassic and Lower Jurassic metavolcanic rocks (Huber and 

Rinehart, 1965; Fiske and Tobisch, 1978)

MINERAL KING ROOF PENDANT

Upper Triassic metasedimentary 

rocks (Christensen, 1963)

MOUNT MORRISON ROOF PENDANT

Ordovician and Silurian(?) metasedimentary rocks (Russell 

and Nokleberg, 1977)

MOUNT MORRISON ROOF PENDANT

Pennsylvanian and Permian (?) 

metasedimentary rocks (Russell and Nokleberg, 1977)

MOUNT MORRISON ROOF PENDANT

Mesozoic metavolcanic rocks

(Russell and Nokleberg, 1977)

FIGURE 7.—Structural diagrams for high-country roof pendants deformed probably during Jurassic orogenies along N. 20°-40°

W. trends. See figure 2 for explanation. Contour data in table 7.

Kistler, 1970) indicates that in that area the regional 

deformation along 20°-40° W. trends continued into 

the Early Cretaceous.

In summary, the recognition of structures with N. 

20°-40° W. trends does not associate them with the 

Late Jurassic Nevadan orogeny because in some areas,
MESOZOIC DEFORMATIONS 17

POLES TO AXIAL PLANES 

ANDSCHISTOSITIES

FOLD AXES AND 

LINEATIONS POLES TO BEDDING

DINKEY CREEK ROOF PENDANT

Lower Paleozoic metasedimentary 

rocks (Kistler and Bateman, 

1966)

STRAWBERRY MINE ROOF PENDANT

Lower Jurassic (?) metasedimentary rocks (Nokleberg, 1970a, 

b)

STRAWBERRY MINE ROOF PENDANT

Lower Cretaceous metaigneous 

rocks (Nokleberg, 1970a,b)

BOYDEN CAVE ROOF PENDANT

Lower Jurassic metasedimentary 

rocks (Girty, 1977a, b)

FIGURE 7.—Continued.

structures with this trend were formed during the 

Triassic, Late Jurassic, or middle Cretaceous (table 1), 

and in others only a Mesozoic age of deformation can be 

determined. In older Paleozoic and lower Mesozoic 

rocks of the high-country roof pendants, coaxial multiple deformations along N. 20°-40° W. trends are 

strongly possible.

CRETACEOUS REGIONAL DEFORMATION

A period of intense folding, cataclasis, and regional 

metamorphism along N. 50°-80° W. trends can be identified in many high-country roof pendants and in areas 

of the western metamorphic belt (table 1). These structures occur throughout a wide area, including the 

Strawberry mine, Pine Creek, Bishop Creek, Ritter 

Range, Mount Morrison, Mount Dana, and Saddlebag 

Lake roof pendants, and the lower Kings River area 

(fig. 1). This generation of structures either is superposed on older generations of structures or occurs in 

Lower Cretaceous metavolcanic or plutonic rocks that 

formed after the Late Jurassic Nevadan orogeny.

ORIENTATION AND STYLE OF STRUCTURES

The diagrams of poles to axial planes and schistosities for this deformation (fig. 8, table 8) show an 

average strike of N. 50°-60° W. with steep to vertical
18 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

TABLE 1 .-Data for figure 7

Diagram Points Contours 

(percent per 1 percent area)

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

92

84

255

215

34

119

98

113

92

163

176

87

29

48

364

93

113

46

92

53

98

158

1.1,2.2,11,20

1.2,2.4,7.1, 12

1,9,17

1,9,17

3,6,12, 18

0.8,4.2,13,21

1,5.1,10, 15.3

1,4,8, 12

1,2,6,10, 14

0.6,2,4,6

0.6,2,8,16

1,2,6, 12

3.2, 10, 33.3

2.1,20

0.4,4,5,10

1,5,20

1,5,30

1,5,15

1,5,15

1,5,10

1,2, 15

0.4, 1, 3, 7

dips (figs. 8A, 8D, 8E, 8G, 81, 8N, 8O, 8Q). The 

diagrams of fold axes and lineations show steep 

plunges because, in most areas, these structures are 

superposed on older structures (figs. 8B, 8F, 8H, 8P). 

In three roof pendants, double maxima of fold axes and 

lineations show superposition of these structures on 

the limbs of folds due to older deformations (figs. 8F, 

8H, 8J, 8P). In four roof pendants, diagrams of poles 

of bedding show a distinct girdle that defines /3-axes 

plunging moderately to steeply within the N. 50°- 60°- 

striking axial planes (figs. 8C, 8K, 8L, 8 M). The 

match between maxima of poles to bedding and maxima of poles to axial planes and schistosities suggests 

an isoclinal style of folding.

Two roof pendants show refolding of strata due to 

this deformation: the northern Ritter Range roof pendant, with rotation of axial planes around a fold axis 

plunging at azimuth 300° (fig. 3D) and of older fold 

axes and axial planes into N. 50°-60° W. trends (fig. 

3E); and the central Ritter Range roof pendant, with 

rotation of bedding around a /3-axis (/32 , fig. 7 B) 

plunging at azimuth 290°.

In all areas, intense regional metamorphism and 

cataclasis are associated with the Cretaceous regional 

deformation. In most roof pendants, contact 

metamorphism obscures regional metamorphism and 

leaves only relict schistosities and lineations; in the 

lower Kings River area, however, zones of intense 

cataclasis and recrystallization were formed under 

conditions of the amphibolite facies in gabbro and 

granitic rocks (Nokleberg, 1975) dated as Late Jurassic 

by Saleeby (1974, 1975, 1978).

TIMING OF DEFORMATION AND REGIONAL TECTONICS

In the lower Kings River area, redeformation of the 

N. 20°-40° W.-trending Nevadan structures in Middle 

and Late Jurassic gabbro and granitic rocks by N. 

50°-80° W.-trending structures (Nokleberg, 1975) 

thereby defines a post-Jurassic age. Crosscutting of 

Lower Cretaceous metavolcanic rocks of the Strawberry mine and Merced Peak roof pendants (Nokleberg, 1970a, b; Peck and others, 1977), which contain 

N. 50°-80° W.-trending structures, by Late Cretaceous 

(80 m.y. old) granitic rocks of the Cathedral Range intrusive epoch (Evernden and Kistler, 1970) thereby 

brackets the deformation as middle Cretaceous. In the 

Mount Dana roof pendant a maximum age of Early 

Cretaceous is defined for the deformation along N. 

50°-80° W. trends (table 1). In this area the younger 

upper part of the Dana sequence has a Rb-Sr isochron 

age of 100 m.y. (R. W. Kistler, unpub. data, 1977) and 

contains open major folds striking N. 60° W. and neaT - 

vertical axial planes (fig. 8L) (Kistler, 1966a, b; Ri.ssell, 1976).

The deformation along N. 50°-80° W. trends also occurred in metavolcanic rocks of the northern Ritter 

Range roof pendant, where it is visible in two small 

plutons: the granodiorite of Billy Lake, and ttie quartz 

diorite of Waugh Lake, which intruded the volcanic 

pile of the pendant (Kistler, 1960, 1966b). A Rb-Sr 

whole-rock age of 99 ±7 m.y. on the plutons (R. W. 

Kistler, unpub. data, 1977) places an older limit of 

Early Cretaceous on this deformation. Undeformed 

Late Cretaceous (84 m.y. old) plutons crosscutting 

these structures in the metavolcanic rocks place a 

younger limit of middle Late Cretaceous on this deformation.

CONTINUING PROBLEMS

EPISODIC OR CONTINUOUS DEFORMATION?

Do the multiple deformations, particularly along N. 

20°-40° W. trends during the Mesozoic, represent 

episodic or continuous responses to compressional subduction along the continental margin? A solution will 

emerge only as more investigations are completed. The 

methods of timing multiple deformations in metamorphic terranes involve bracketing relations from such 

data as the ages of younger less deformed bedrock that 

overlies or crosscuts older more highly deformed bedrock. Thus, this method indicates only episodes of deformation; continuous deformational patterns will be 

revealed as enough episodes are defined to fill in all 

gaps. The solution to this problem is critical to an ultimate understanding of the formation of composite 

batholiths.
CONCLUSIONS 19

ROLE OF GRANITIC INTRUSIONS

Five periods of granitic intrusion are defined for 

Mesozoic time; granitic rocks of each period form a narrow belt along different trends in California, Oregon, 

and Nevada (Evernden and Kistler, 1970). Episodic regional deformation and volcanism are associated with 

these granitic intrusions (Kistler and others, 1971), 

and so the presence of granitic rocks has several effects 

on the multiple deformations (Brook and others, 1974; 

Russell and Nokleberg, 1977). One effect is the shielding of roof pendants, where bordered by major granitic 

intrusions, from later deformations. For example, the 

Log Cabin mine and Bishop Creek roof pendants contain structures due to the Devonian and Mississippian 

regional deformation but not to later deformations because of the presence of Late Triassic (210 m.y. old) 

granitic rocks of the Lee Vining intrusive epoch; similar shieldings of wallrocks from later deformations are 

listed in table 1. A second effect is the minimal deformation of wallrocks during the emplacement of granitic magmas, except for a few examples of forceful 

emplacement reported by Bateman (1965). One conclusion, based on the correlation of superposed deformations across the central Sierra Nevada, is that the intrusion of granite was predominantly passive (Kistler, 

1966a; Brook and others, 1974; Russell and Nokleberg, 

1977). A third effect is that, in areas of the western 

metamorphic belt, regionally deformed plutons can be 

recognized and delineated (Nokleberg, 1975).

CONJUGATE FOLDS

In a recent study of conjugate folds and crenulations 

in the central Sierra Nevada, Tobisch and Fiske (1976) 

stated that: (1) the crenulation or folding of slaty 

cleavage or schistosity in one area may not be contemporaneous with a geometrically comparable structure 

in another area, (2) crenulations in one area may even 

predate slaty cleavage or schistosity in another area, 

and (3) the fold chronology that defines multiple folding in the Sierra Nevada needs reexamination. We 

agree that conjugate folding of schistosities has occurred but, in our view, only on a limited scale; we 

disagree with the concept that refolding of a slaty 

cleavage in most areas is related to the formation of 

conjugate folds that represent different stages of the 

Nevadan orogeny.

We assert that the refolding of slaty cleavage or 

axial-plane schistosities and associated folds is principally related to superposed regional deformations, for 

several reasons. First, examples of conjugate folds are 

quite rare. Tobisch and Fiske found only a few such 

folds; their figure 5a shows mainly northwest- and 

east-trending, but no west- or north-trending, folds, as

the figure caption states; their figure 5b shows only 

random orientations of folds with no clearly discernible 

maxima of conjugate pairs. Second, many of the westtrending halves of conjugate folds described by Tobisch 

and Fiske may represent superposed folds due to a 

later deformation; their figure 3a shows west-trending 

conjugate folds crossing a N. 20°-40° W.-trending 

schistosity associated with the Nevadan orogeny in the 

central part of the Ritter Range roof pendant. The 

west-trending folds are actually N. 50°-80° W.- 

trending folds that may have formed during the early 

Late Cretaceous regional deformation. Third, Tobisch 

and Fiske state in a footnote (1976, p. 1419) that "*** 

some zones of slaty cleavage in the southwest Ritter 

Range pendant may postdate the Nevadan deformation"; their claim is supported by radiometric age dating of rocks in the Ritter Range roof pendant (R. W. 

Kistler, T. W. Stern, and Mitsunobu Tatsumoto, personal communs., 1973-75). These reasons clearly show 

that superposed schistosities and, presumably, superposed folds were formed during separate deformations 

in one of the type areas of Tobisch and Fiske for conjugate folds.

In contrast to the notion that the conjugate refolding 

of schistosities represents a continuation of the Nevadan orogeny, our study shows many distinct periods of 

regional deformation. Many statements by Tobisch and 

Fiske support our study: (1) three periods of deformation occur in Paleozoic metasedimentary rocks—and 

only the younger two occur in metavolcanic rocks of 

late Paleozoic and Mesozoic age; (2) an axial-plane 

cleavage or schistosity occurs in Paleozoic rocks that 

predates the Nevadan cleavage; and (3) some zones of 

slaty cleavage or schistosity in the Ritter Range roof 

pendant may postdate the Nevadan orogeny.

CONCLUSIONS

Analysis of structural and stratigraphic data indicates that several regional deformations occurred in 

the central Sierra Nevada during the Paleozoic and 

Mesozoic. Each regional deformation is characterized 

by a combination of folds, cataclasis, regional 

metamorphism, and faulting. The oldest recognized regional deformation occurred along northward trends 

during the Devonian to Mississippian and occurs in 

roof pendants containing lower Paleozoic rocks along 

the center and crest of the range. An angular unconformity formed during the Devonian to Mississippian 

in the Mount Morrison roof pendant that separates 

older thrice-deformed rocks from younger twicedeformed rocks. A period of uplift, erosion, and commencement of Andean-type volcanism occurred in the 

Permian to Triassic and is now represented by an an-
20 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

POLES TO AXIAL PLANES 

ANDSCHISTOSITIES

FOLD AXES AND 

LINEATIONS POLES TO BEDDING

STRAWBERRY MINE ROOF PENDANT

Lower Jurassic!?) metasedimentary rocks (Nokleberg, 1970a,b)

STRAWBERRY MINE ROOF PENDANT

Lower Cretaceous metaigneous 

rocks (Nokleberg, 1970a, b)

MOUNT MORRISION ROOF PENDANT

Ordovician and Silurian (?) metasedimantary rocks (Russell 

and Nokleberg, 1977)

MOUNT MORRISON ROOF PENDANT

Pennsylvanian and Permian (?) 

metasedimentary rocks (Russell and Nokleberg, 1977)

MOUNT MORRISON ROOF PENDANT

Mesozoic metavolcanic rocks 

(Russell and Nokleberg, 1977)

FIGURE 8.—Structural diagrams for high-country roof pendants and areas of the western metamorphic belt deformed during the 

Cretaceous along N. 50°-80° W. trends. See figure 2 for explanation. Contour data in table 8.

gular unconformity in several roof pendants along the 

crest of the range. During the Triassic, regional deformations occurred along N. 20°-30° W. trends in several

high-country roof pendants and in the Calaveras Formation of the western metamorphic belt. A later Early 

Middle Jurassic deformation occurred along N. 30°-60°
CONCLUSIONS 21

POLES TO AXIAL PLANES 

ANDSCHISTOSITIES

FOLD AXES AND 

LINEATIONS POLES TO BEDDING

MOUNT DANA ROOF PENDANT

Lower Cretaceous metavolcanic 

rocks (Kistler, 1966a, b; Russell, 1976)

DINKEY CREEK ROOF PENDANT

Lower Paleozoic metasedimentary rocks (Kistler and Bateman, 1966)

SADDLEBAG LAKE ROOF PENDANT

Permian and Triassic metavolcanic 

rocks (Brook, 1972, 1974, 

1977)

LOWER KINGS RIVER ROOF PENDANT

Metasedimentary rocks Calaveras(?) 

Formation, upper Paleozoic (?) 

(Nokleberg, 1975)

LOWER KINGS RIVER ROOF PENDANT

Serpentinite, Permian and Triassic 

(Nokleberg, 1975)

FIGURE 8.—Continued.

E. trends in the western metamorphic belt and Boyden 

Cave roof pendant. In the high-country roof pendants, 

the Triassic structures are crosscut by Late Triassic

granitic rocks of the Lee Vining intrusive epoch. The 

Late Jurassic Nevadan orogeny consisted of both 

right-lateral strike slip and underthrusting along N.
22 PALEOZOIC AND MESOZOIC DEFORMATIONS IN THE CENTRAL SIERRA NEVADA, CALIFORNIA

TABLE S.-Data for figure 8

Diagram Points Contours 

(percent per 1 percent area)

A

B

C

D

E

F

G

H

I

J

K

L

M

N

0

P

Q

103

42

136

73

85

50

17

16

82

54

66

175

45

25

59

56

18

1,5,10,20

1,5,10,20

1,2,4,6

1,5,10

1.1,12,25

0.2,10,20,30

5,10,15,20,30

5,10,20

1,4,12,28

2,4,10,18

0.6,2,4,8

0.5,3,5

2.2,6.6

8, 24, 32

1,2,4,8,12

1,4,12

1,10,20

20°-40° W. trends. This orogeny ended with the 

emplacement of Late Jurassic granitic rocks of the 

Yosemite intrusive epoch. Some early intrusions of this 

epoch may have been emplaced during the waning 

stages of the orogeny. One or two high-country roof 

pendants were deformed along N. 20°-40° W. trends 

during the Nevadan orogeny, but many other roof 

pendants could have been deformed along the same 

trends somewhat earlier or later. The last major regional deformation occurred during the early Late Cretaceous, when most roof pendants and parts of the 

western metamorphic belt were deformed along N. 

50°-80° W. trends. This deformation was followed by 

the Late Cretaceous Cathedral Range intrusive epoch.

In the roof pendants of the eastern Sierra Nevada, 

multiply folded thin formations are found instead of 

homoclinal thick formations, as proposed earlier. 

Paleozoic rocks of the western metamorphic belt are 

folded around axes that plunge steeply east across the 

batholith, whereas Mesozoic rocks of the western 

metamorphic belt are folded around axes plunging 

moderately to steeply southeast instead of subhorizontal and parallel to the batholith. Older thrice-deformed 

roof pendants of early Paleozoic age occur in the center 

and along the east side of the batholith. The highcountry roof pendants show considerable differences in 

stratigraphy, structural trends, and number of deformations in comparison to areas of the western metamorphic belt.

The available evidence suggests episodic regional deformations. Some roof pendants containing lower 

Paleozoic and lower Mesozoic rocks may have been 

multiply deformed along coaxial N. 20°-40° W. trends. 

The role of granitic intrusions has been to shield encircled roof pendants from subsequent deformation, although regionally deformed plutons are recognized in 

the western metamorphic belt. The correlation of 

superposed deformations across the range suggests 

that granitic intrusions were mainly passive in the 

central Sierra Nevada.

ACKNOWLEDGMENTS

We are grateful for many discussions of this topic 

with C. A. Brook, S. J. Russell, G. H. Girty, and S. F. 

Cebull. We thank R. A. Loney and C. A. Brook for their 

reviews of the manuscript. We are indebted to the excellent older studies by many geologists of the central 

Sierra Nevada; if we have been able to see further into 

the geology of the region, it is only because we have 

stood on their shoulders for a better view.

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