Tectonics of the Pot war Plateau Region and the 

Development of Syntaxes, Punjab, Pakistan

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Tectonics of the Potwar Plateau Region and the 

Development of Syntaxes, Punjab, Pakistan

By HARALD DREWES

U.S. GEOLOGICAL SURVEY BULLETIN 2126

An analysis of structural features of the foreland area, 

fold-and-thrust zone, shingled thrust zone, and orogenic syntaxes 

in a part of the Himalayan orogen

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1995
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

For sale by U.S. Geological Survey, Information Services

Box 25286, Federal Center

Denver, CO 80225

Any use of trade, product, or firm names in this publication is for descriptive purposes only and 

does not imply endorsement by the U.S. Government

Library of Congress Cataloging-in-Publication Data

Drewes, Harald, 1927-

Tectonics of the Potwar Plateau region and the development of syntaxes, Punjab, Pakistan / by Harald Drewes.

p. cm. (U.S. Geological Survey bulletin ; 2126)

Includes bibliographical references.

Supt. of Docs, no.: I 19.3:2126

1. Geology, Structural Pakistan Potwar Plateau. I. Title. II. Series. 

QE75.B9 no. 2126 

[QE634.P18] 

557.3 s dc20

[551.8'095491'4] 95-7440

CIP
CONTENTS

Abstract........................................................................................................................... 1

Introduction.................................................................................................................... 1

Tectonic Setting.............................................................................................................. 3

Regional Relationships........................................................................................... 3

North Pakistan Tectonic Zones............................................................................... 3

Lateral Tectonic Variations.................................................................................... 6

Potwar Plateau Region Structures.................................................................................. 6

Foreland Area and Indian Basement...................................................................... 6

Gravity Data................................................................................................... 7

Magnetic Data................................................................................................. 7

Seismic Data................................................................................................... 8

Potwar Plateau Fold-and-Thrust Zone.................................................................... 8

Salt Range Structures...................................................................................... 8

Salt Range Thrust Fault.......................................................................... 8

Structural Implications from the Stratigraphic Record........................... 9

Slump Features....................................................................................... 12

Salt Tectonics and Steep Faults.............................................................. 13

Structures at the Ends of the Salt Range................................................. 13

Potwar Plateau Structures............................................................................... 14

Successor Foreland Basins..................................................................... 14

Folds.........................................................,......................................:...... 15

Thrust Faults........................................................................................... 18

Shingled Thrust-fault Zone..................................................................................... 19

Lower Thrust Plate......................................................................................... 19

Upper Thrust Plate.......................................................................................... 19

Tectonic Development.................................................................................................... 20

Pre-Himalayan Tectonic Development.................................................................. 20

Himalayan Orogenic Events................................................................................... 20

References.............................................................................................................. 21

FIGURES

1. Index map showing location of Potwar Plateau area in the context of the Indo-Australian and

Eurasian plates and the Himalayan orogen ................................................................................................................. 2

2. Generalized geologic map of north-central Pakistan showing setting of the Potwar Plateau area............................. 4

3. Tectonic map of the Potwar Plateau and adjacent areas, showing tracts A-C and subtracts reviewed in text........... 10

4. Diagrammatic longitudinal profile of the Salt Range, Pakistan, showing selected Stratigraphic and

lithologic features..:..................................................................................................................................................... 12

5. Block diagram series showing development of syntaxes in three stages, Miocene-Holocene ................................... 15

III

TECTONICS OF THE POTWAR PLATEAU REGION AND THE 

DEVELOPMENT OF SYNTAXES, PUNJAB, PAKISTAN

By Harald Drewes

ABSTRACT

The structural features of the Potwar Plateau region are 

dominated by a large southeastward-convex deformation 

lobe. This lobe includes abundant thin-skinned thrust faults, 

some strike-slip and normal faults, and many folds.

The tectonic setting of the region is along the southern 

foreland of the Himalayan orogen. Specifically, it is on the 

western margin of the subducting Indo-Australian plate 

where this plate descends beneath both the orogen and, ultimately, the Eurasian plate. As a result of compression across 

the region, deposits of the Tethyan seaway and older formations from the Eurasian plate are being transported onto the 

subducting plate as a stack of thrust plates. Where the leading edge (actually the line at which descent begins) meets the 

lateral edge of the subducting Indo-Australian plate, the 

stack of thrust plates flanking the orogen are pivoted about 

nearly vertical axes and gradually merge with a left-slip or 

left-oblique slip tectonic belt along the northwest side of the 

lower Indus River. The pivot points affect separately and 

complexly the several major thrust plates, and are referred to 

as syntaxes. As each of these thrust plates moved forward of 

the preceding one, each was pivoted, thereby leaving aligned 

syntaxes of progressively younger tectonic levels, northeast 

to southwest.

The Potwar Plateau region straddles an exceptionally 

broad segment of the fold-and-thrust zone, plus adjacent 

parts of the more distal Indo-Gangetic foreland basin area 

and the more proximal shingled thrust-fault zone. The foreland basin area comprises a basement of Proterozoic 

metasedimentary and metavolcanic(?) rocks of the Indian 

part of the Indo-Australian plate that is overlain mainly by 

Pleistocene to Holocene alluvial deposits. The main structural features of the foreland basin area are faults and possibly stocks in the basement rocks.

The fold-and-thrust zone is between the Main Frontal 

thrust fault, locally known as the Salt Range thrust fault, and 

the Main Boundary thrust fault, also known as the Murree 

thrust fault, to the northeast. The Salt Range thrust fault dips 

gently beneath the fold-and-thrust zone and, because of 

extensive salt tectonism initiated from a sedimentary unit at 

the base of the plate, has strongly disrupted the lower part

and older rocks of this tectonic zone. A down-to-the-northwest offset in the basement rocks has caused thrust ramping 

of Mesozoic and Paleogene rocks in the central part of the 

Salt Range. The Neogene and older rocks of this tectonic 

zone are folded and sparsely faulted, forming tracts of three 

intensities of deformation. The tract having an intermediate 

intensity of deformation had optimum conditions for the 

anticlinal entrapment of oil, an association that may provide 

guidance for further oil exploration.

The lateral extent of the fold-and-thrust zone is limited 

by syntaxes. The syntaxes are in the major, successive, thinskin thrust plates where they are warped around the northwest edge of the Indo-Australian plate. As these syntaxes are 

overridden and incorporated into deeper tectonic environments, lateral horizontal faulting gave way to metamorphism, plutonism, and upward mass movement.

The shingled thrust-fault zone has a younger underlying 

terrane of tightly folded and abundantly faulted Paleozoic to 

Paleogene rocks and an overlying older terrane of Proterozoic metasedimentary rocks whose internal structures are 

poorly documented but may include folded faults.

Recorded deformation of the Potwar Plateau area is 

mostly Neogene; deformation continued at least into late 

Pleistocene and likely is ongoing. This period of major 

north-south compressive deformation closed the Tethyan 

seaway during or after Eocene time, which is the time in 

which the plate collision began, according to the local 

record. Older Himalayan deformation, recognized to the 

north, has not been recognized locally. In general, deformation youngs southeastward; deformational events in the 

northern parts of the study area are Miocene and in the southern half of the study area they are dated at about 9 to 0.4 Ma. 

Still earlier (pre-orogenic) events, related to Permian glaciation and Eocambrian salt deposition, are discussed briefly.

INTRODUCTION

This review of the tectonics of the Potwar Plateau 

region (fig. 1) is part of a cooperative U.S. Geological 

Survey (USGS) and Geological Survey of Pakistan (GSP) 

study of the coal resources of the region. Because the coal
2 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

40' 50' 60' 70' 80' 90' 100' 110'

Potwar Plateau region 

otwar Plateau study area

0 R 0 G E N I

/ Hotspot 

Traces 

plate moves 

North

ST «ALIAN PLAT

To Kerguelen Island

(at latitude of study area] 

EXPLANATION

MAJOR TECTONIC BOUNDARY 

Thrust fault movement dominant

Strike-slip fault movement dominant

Spreading center Heavy single lines are transform faults; 

paired light lines are mid-oceanic spreading zone

Tectonic transport direction

Figure 1. Index map showing location of the Potwar Plateau area in context of the Indo-Australian and Eurasian plates and the Himalayan 

orogen.
TECTONIC SETTING

resources are found in the Permian to Tertiary rocks, the 

present review focuses heavily on the effects of a young 

compressional deformation of the Cretaceous to Holocene 

Himalayan orogen. This review relies mainly on analysis of 

surface structural features augmented by airborne gravity 

and magnetic data, and by compilation of published work.

The Potwar Plateau region straddles several major tectonic zones whose characteristic features are well illustrated 

by rock distribution and implied structures (unpub. mapping 

compiled by M.A Bhatti, Feroz-ud-din, J.W. McDougall, 

P.D. Warwick, and Harald Drewes, 1991-94). However, this 

region does not extend far enough laterally to adequately 

illustrate the uncommon syntaxes bounding the tectonic 

zones (fig. 2). The syntaxes are major sites of adjustment to 

transtectonic zone stresses, where several major thrust plates 

impinge on the subducting Indo-Australian continental plate.

The tectonic zonation of the Potwar Plateau region is 

typical of most erogenic belts in that there is a foreland area 

or zone, a fold-and-thrust zone, a shingled thrust zone, and, 

north of the study region, a core zone or central suture. The 

syntaxes, however, are uncommon. The frontal part of the 

Himalayan erogenic belt in the Potwar region is strongly 

influenced by the presence of the salt- and gypsum-bearing 

Eocambrian Salt Range Formation, along which major 

detachment took place, probably distributed throughout the 

ductile sheet. The rocks above the detachment level were 

deformed disharmonically relative to the underlying rocks. 

The result of these three major influences changes in tectonic zones, syntaxes, and salt-bearing rocks was to have 

thrust plates develop forward (southeastward) and downward 

(younger plates underlie older ones). Upon reaching shallow 

tectonic levels, and thus no longer confined laterally, the 

plates spread laterally over young foreland basin deposits.

TECTONIC SETTING 

REGIONAL RELATIONSHIPS

The Potwar Plateau region is on the northwestern part 

of the Indo-Australian plate (fig. 1). This plate is being 

driven northward beneath the Eurasian plate from a spreading center in the Indian Ocean (McKenzie and Sclater, 

1971). This major underthrusting or stacking of continental 

plates is supported by gravity and seismic refraction studies 

which show twice the normal thickness of continental crust 

beneath northern Pakistan and the high Himalaya of Tibet 

(Finetti and others, 1981). An extensive belt of compressively deformed rocks, the Himalayan orogen, is above the 

stacked continental plates. Plate convergence was started by 

Cretaceous time and is ongoing (Lefort, 1975).

The Indian subcontinent of the northward-moving plate 

has a distinctively rectilinear leading edge with a central part 

having a concave-northward lobate form (main Himalayan 

tectonic lobe) ending abruptly to the east and the west, at

which points the plate boundary trends southerly (fig. 1). 

Whereas the leading edge is associated with the more common kinds of compressional deformation, the southerly 

trending segments are sites of strike-slip and oblique-slip 

deformation to points far to the south. At these points the 

dominant east-west trends prevail again, south of Indonesia 

to the east, and south of Iran to the west.

Many rocks of the Himalayan orogen are sedimentary 

deposits, or their derivative metasedimentary rocks, of the 

Tethys seaway. These overlie Proterozoic and Paleozoic sedimentary and metamorphic rocks. In the interior parts of the 

orogen, these rocks are intruded by many granitic bodies and 

have one or several belts of intercalated ophiolites.

Compressional stress of the continent-continent collision was strong and long-lived. Consequently the interior 

region is dominated by tremendous uplift, and broad flanking regions are dominated by thrust faulting and folding. 

Because of the transverse asymmetry generated by the northward subduction of subcontinent India, the flanking 

deformed regions are also asymmetric, in the sense that the 

southern of these belts is broader and more continuous, aside 

from the transform-fault-like offsets, whereas the northern 

belt is generally narrower and less continuous.

The Potwar Plateau region is along the frontal part of 

the southern deformed belt, at the juncture of the Indian 

lobate leading edge of the Indo-Australian plate and the 

complex oblique-slip western offset of that edge. The southernmost part of the region, just south of the area of the Salt 

Range, has exposures at Sargodha of the northernmost 

exposed part of the subducting plate. The Potwar Plateau 

region itself includes part or all of several tectonic zones 

common to most orogenic belts.

NORTH PAKISTAN TECTONIC ZONES

A transect across the area of figure 2, from south to 

north, touches on part of the Indo-Gangetic foreland area and 

the Salt Range thrust fault (or frontal line), the fold-andthrust zone, the shingled thrust zone, and an interior massively intruded zone that includes one or two ophiolite belts 

that may mark the roots of island arcs. Still farther north, the 

Main Karakorum thrust fault is the suture along the orogenic 

core, beyond which the tectonic zonation generally reverses.

In the south, the Indo-Gangetic plains make up the 

youngest depocenter of a series of southward-shifting foreland basins. Throughout the sequence of events, the basin 

axes have remained parallel with the adjacent tectonic zones. 

This is shown by the path of the Ganges River in India (fig. 

1) where tributaries and upper reaches of the main river cross 

the structural grain but lower reaches are parallel to structures. Central segments of the Jhelum, Chenal, and Ravi Rivers of Pakistan also flow subparallel to the tectonic zones, 

after their upper reaches cross them. In western Pakistan, 

structures trend southwestward and the Indus River, after
TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

71' IT 73* 74' 75'

POTWAR PLATEAU 

STUDY AREA

33' 

32'
TECTONIC SETTING 

EXPLANATION

Alluvium (Quaternary) Deposits of basins or lowlands

Sedimentary and metasedimentary rocks (Quaternary to Proterozoic) Mainly rocks 

of the foothills; also present in the Himalayas

Granite (Pliocene to Jurassic) Mainly rocks of the high Himalayas; small bodies 

in the foothills

Diorite (Tertiary? to Mesozolc) Rocks of the high Himalayas 

Amphibollte (Mesozoic?) Includes ophiolite; rocks of the high Himalayas

Thrust fault Dotted where concealed, sawteeth on upper plate

Strike-slip fault Dotted where concealed or where it becomes a concealed 

(blind) oblique-slip ramp. Arrow couple shows relative movement

Fold axis

Pivot point Approximate site of vertical pivot axis for syntax; showing, by number, 

order of inception

 ^^^"^ Tectonic zones and foreland area Discussed in text; dashed where extent remains 

undetermined

Figure 2 (above and facing page). Generalized geologic map of north-central Pakistan showing setting of the Potwar Plateau study area. AC, Attock-Cherat Range; 

GM, Gandghar Mountains; HM, Hazara Mountains; MH, Margala Hills; BG, Bunha 

River gap. Geology adapted from Kazmi and Rana (1982) and unpublished geologic 

mapping compiled by M.A Bhatti, Feroz-ud-din, J.W. McDougall, P.D. Warwick, and 

Harald Drewes (1991-94).

P1

first crossing the structural grain, trends parallel to the 

depocenter axis of the Indo-Gangetic foreland without much 

change in flow direction.

Characteristically, along the frontal line the foreland 

basin of an advancing orogenic flank is sharply defined but 

its opposite side is gradational and has an irregularly trending trace, and thus it is more suitably referred to as a foreland 

area than a foreland zone. The southern margin of the foreland area near the Potwar Plateau region is diffuse; several 

low hills at Sargodha (fig. 2) expose Proterozoic argillite and 

metaquartzite of the Indian subcontinent, apparently marking a local rise in the foreland basin floor.

The Holocene alluvium of the foreland basin is underlain by Pleistocene deposits which are tilted and locally 

upended near the frontal line, as determined in a few places 

by direct observation (Yeats and others, 1984, and this 

study) and in other sites by drill-hole or seismic data, to indicate the ongoing deformation process.

The frontal line, regionally known as the Main Frontal 

thrust fault, and locally known as the Salt Range thrust fault, 

is concealed by the youngest deposits; these deposits are 

mostly alluvial and may include slump debris along the foot 

of the Salt Range. The frontal line is used here specifically to 

designate the most distally situated structural break that is 

known or likely to be continuous in the subsurface with the 

structures of the main zones of deformation. Exposed segments of range-front faults are shown by Yeats and others

(1984) at Ghundi and east of Khwera (fig. 2), but we infer 

that still lower structures underlie these sites.

Northwest of the frontal line is the fold-and-thrust zone, 

which is characterized by many open folds and a few reverse 

or thrust faults. Most rocks of this zone are the older rocks of 

two successor foreland basins, containing the Miocene and 

Pliocene Siwalik Group and the Miocene Rawalpindi Group. 

These rocks appear to have been carried on the older rocks, 

which were thrust along the salt-bearing Eocambrian Salt 

Range Formation. Many of the structures of the fold-andthrust zone are disharmonic over the basal detachment structure, which is the gradually northwestward descending Salt 

Range thrust fault. The cross-sectional taper, or wedge of 

deformed rock, is given as l°-4° (Crawford, 1974). The 

Main Boundary thrust fault marks the proximal margin of the 

fold-and-thrust zone.

North of the Main Boundary thrust fault is the shingled 

thrust-fault zone in which mainly older rocks are abundantly 

slivered into thin thrust plates and in which folds are mainly 

tight, with their axial planes subparallel to the adjacent thrust 

faults. The rocks of the distal part of this zone are unmetamorphosed and stocks are absent, but scattered veins and 

dikes do exist. The proximal part of this zone, north of the 

study area, is metamorphosed, mostly to the greenschist 

facies, and is intruded by many aplite sheets and scattered granitic stocks. The Main Mantle thrust fault forms the proximal 

boundary of the shingled thrust-fault zone, as shown on the 

Pakistan geologic maps (Kazmi and Rana, 1982).
TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

The interior or hinterland zone has the highest metamorphic grade (mostly greenschist in the study area) of 

metasedimentary and meta-igneous rock, which are massively invaded by granitic, dioritic, and ophiolitic rocks. 

Rocks of this interior zone are uplifted and deeply eroded. 

Continued present-day uplift is indicated by local relief of 4 

km, by the young (5-8 Ma) cooling ages of the rock, and by 

the signs of young faulting (Treloar and others, 1991) that 

are exceptions to the general southward younging of compressive deformation.

LATERAL TECTONIC VARIATIONS

The systematic tectonic zonation of a transect through 

the Potwar Plateau area is common to many parts of the 

southern flank of the Himalayan orogen, but some structural 

variations also exist laterally along the orogenic belt. Furthermore, the fold-and-thrust zone of India is narrower 

(about 50 km) than it is in the Potwar region (about 180 km), 

which probably reflects an increase in the cross-sectional 

taper in India to as much as 8° (Acharyya and Ray, 1982).

The largest features of lateral variation are the transform-fault-like major offsets of the entire orogen, such as on 

the lateral margins of the Indian subcontinental part of the 

plate. The eastern offset of these major features is probably 

a right-lateral fault, and is of little concern here because it is 

far away in Assam and Bangladesh. However, the western 

offset extends southwestward, from the west side of the Potwar Plateau study area, as an alternation of left-lateral faults 

and fold-and-thrust-zone lobes. Apparently, the subducting 

part of the Indo-Australian plate is moving obliquely to the 

trend of these surface structures, resulting in a skewed structural pattern. The first of the minor lobate fronts is just southwest of Mianwali (fig. 2), separated from the Salt Range lobe 

by the Kalabagh reentrant, a structural embayment referred 

to as a syntaxis.

Syntaxes are remarkable transverse structures of moderate scale that show the existence of pivotal movement 

about a vertical axis, generally analogous to the closing of an 

open nutcracker lying flat on a table. Local movements 

recorded on the three syntaxes shown on figure 2 are complex and young; movement is "complex" because of the variation of movement from site to site in any one syntaxis.

The Indus River syntaxis (Kalabagh syntaxis; PS on fig. 

2) centers on the structural and topographic embayment 

along the segment of the Indus River west of the Salt Range. 

It is underlain by Pleistocene-Holocene deposits upon which 

adjacent Tertiary and older rocks are being pushed. Its upper 

bounding fault seems to be along, or slightly above, the Main 

Frontal thrust-fault system. The Indus River syntaxis seems, 

then, to be a lateral flaring out at the high structural level of 

the most forward part of the deforming rocks. Perhaps the 

upward flowage of salt or gypsum in geophysically identified stocks near Mianwali (Drewes and Ahmad, in press) is 

fostered or enhanced by such lateral compression. The

Kalabagh fault, bounding this syntaxis to the east, is 

described in a following section.

The Jhelum River syntaxis (?2 on fig. 2; in some 

accounts the Hazara syntaxis) is at a higher tectonic level, 

involving rocks between the Main Frontal thrust fault and 

the Panjal thrust fault (fig. 3 on pages 10-11), essentially all 

of the fold-and-thrust-zone rocks and the distal part of the 

shingled thrust-fault zone. It bounds the study area to the east 

near Murree and is a few kilometers east of the southern part 

of the area. The western side of this syntaxis is customarily 

shown as a left-lateral fault which offsets the Siwalik Group 

and some internal small thrust faults, as well as the Main 

Boundary thrust fault (Kazmi and Rana, 1982).

The Nanga Parbat syntaxis (P-| on fig. 2) is in higher 

tectonic levels than the Jhelum River syntaxis, although it 

involves mostly older gneiss plus granitic rocks that have 

young cooling ages (Treloar and others, 1991). In this case, 

the main movement recorded on the structures bounding the 

syntaxis is vertical, although in places oblique-slip movement is noted. But even here the vertical movement is coupled with an upward and outward lateral sense of flowage 

that reflects the "nutcracker" effect in the rocks of the plate 

between the Panjal and Main Mantle thrust faults (fig. 2).

The three syntaxes of the Potwar Plateau region probably developed in response to concurrent thrust faulting and 

adjustment of major thrust plates around the northwest edge 

of the subducting plate. The pivot points of the syntaxes are 

aligned, not only with one another, but also with the southwest trend of the orogenic belt along the western strike-slip 

margin of the Indian subcontinent part of the plate. Furthermore, from northeast to southwest, the pivot points shift systematically to lower-level younger plates. Apparently then, 

as the frontal line shifted forward along a newly developed 

thrust system in younger and younger rocks, ultimately in 

successor foreland basin deposits, the rotation of the deforming rocks around the edge of the subducting plate affected 

the younger plates, too. Each major plate was bent, or 

rotated, in sequence.

POTWAR PLATEAU REGION 

STRUCTURES

Selected structural features of the three tectonic zones 

represented in the study area are reviewed from southeast to 

northwest. Geophysically determined structural features 

attributed to the subducting plate are mostly discussed with 

the foreland features, even though they are beneath more 

proximal positions.

FORELAND AREA AND INDIAN 

BASEMENT

The foreland area, southeast of the Salt Range and 

extending into the Indus River syntaxis, provides little
POTWAR PLATEAU REGION STRUCTURES

surface data on its structural condition. The frontal line is 

concealed by the youngest alluvial deposits of the Jhelum 

and Indus Rivers and by a combination of alluvial fans, 

aprons, and slump deposits at the base of the Salt Range.

At several sites young deposits near the frontal line are 

folded or tilted, indicating that deformation is extremely 

young. Indeed, in the Pabbi Hills, east of the Salt Range and 

south of Jhelum (fig. 2), a drill hole that penetrated a thrust 

fault underlying a gentle anticline in the upper part of the 

Siwalik Group was sheared by late movement on the fault. 

By the definition used here for the recognition of the frontal 

line the most proximal fault having structural continuity 

with the main deformed belt the Pabbi Hills are in the foldand-thrust zone rather than the foreland area, and the frontal 

line is concealed south of those hills. Therefore, the thrust 

faults at the east end of the Salt Range, near the sigmoidal 

bend of the range front (fig. 2), and those faults northwest of 

Jhelum are splay faults off the underlying extension of the 

Salt Range thrust fault. The splay faults are informative 

about the condition of the rocks at the northern edge of the 

foreland area. These rocks are being folded and almost 

simultaneously faulted, thereby being incorporated into the 

fold-and-thrust zone.

Signs of young anticlinal warping also exist at a site 

near Lilla, a few kilometers southeast of the central part of 

the Salt Range (fig. 3). According to Lillie and others (1987), 

drill-hole data show Pleistocene(?) rocks are arched, possibly over a salt core, at shallow depth beneath alluvial cover.

Northwest of Kalabagh, Pleistocene rocks are also 

faulted and upended, and again the question arises as to precisely where to place the frontal line. The Surghar Range 

thrust fault of McDougall and Hussain (1991) is the southernmost exposed thrust fault of those faults west of the Kalabagh right-lateral fault. Along this thrust fault, Jurassic to 

Paleogene rocks are placed upon the Neogene Siwalik 

Group. This thrust fault may be the extension of the Salt 

Range thrust fault, and thus the apparent frontal line, but it is 

also possible that a still lower, concealed structure underlies 

the Siwalik Group and some Kalabagh Conglomerate, and 

that this postulated still lower structure trends around the 

head of the Indus River syntaxis, to form the real frontal line.

Airborne gravity and magnetic maps provide indirect 

evidence of structures underlying the foreland area, as well 

as the adjacent part of the fold-and-thrust zone. The basic 

gravity data are from Oil and Gas Development Corporation 

(OGDC) reports, cited in the following sections. While geophysical anomalies may show the existence of structural features in the subsurface, their absence need not deny the 

presence of structures, which are recognizable only where 

they are associated with certain magnetic or gravity contrasts.

GRAVITY DATA

The gravity maps of Waheed-ud-din (1967, 1971) and 

Waheed-ud-din and Lotyshev (1970) show relatively high 

density rocks (near the surface?) in the northwestern part of

the Potwar Plateau region and progressively more low-density rocks (near the surface?) to the southeast. This systematic variation across the region probably reflects the presence 

in outcrop of the Proterozoic metasedimentary rocks in the 

Attock-Cherat Range and Gandghar and Hazara Mountains, 

Paleozoic and Mesozoic sedimentary rocks in the next 

ranges to the southeast, such as the Kala Chitta Range and 

Margala Hills, weakly indurated Tertiary rocks across the 

Potwar Plateau, and, excepting for the Salt Range, alluvium 

in the foreland area to the southeast.

This general gravity gradient is interrupted by two 

minor reversals (gravity anomaly lines G, the one north of 

Pindi Gheb and the other south of Chakwal, fig. 3), which 

suggest the presence in the subsurface of raised masses of 

denser, and thus probably older, rocks northwest of the gravity anomaly lines. These lines are inferred to be reverse fault 

segments of the thrust fault, which are ramped up across offsets on a flat-lying fault system. The inferred offset must be 

young to have affected movement on the Salt Range thrust 

fault in the subsurface. The pattern of these inferred faults is 

similar to that of the magnetic features found southeast of the 

frontal line, and so the young offset of the basement rocks 

marked by gravity anomalies may be reactivated structures.

The southernmost linear gravity feature is offset in 

three places, and from west to east the segments were shifted 

southward. The significance of these offsets may be understood from the magnetic data.

MAGNETIC DATA

The airborne magnetic map of Voskresensky (1965) 

shows tracts of diverse magnetic patterns and linear zones of 

anomalies that imply structural control. Interpretations of 

these patterns and linear zones are illustrated in figure 3. The 

most prominent feature is a steep linear magnetic anomaly 

that extends northwest from the northeast side of the Sargodha Hills (fig. 2), through the Salt Range north of Kushab 

(fig. 3), across the western part of the Potwar Plateau, and to 

the Indus River a few kilometers north of its junction with 

the Soan River. The southeastern third of the block northeast 

of this linear magnetic structure has a distinctive pattern of 

closely spaced magnetic highs and lows, typical of volcanic 

or volcanogenic terrane, such as the argillite or subgray wacke of the Sargodha Hills. The same magnetic pattern 

occurs farther northwest on the southwestern block, suggesting a right-slip offset of many kilometers.

Small, linear, west-northwest-trending magnetic anomalies merge with the main linear features in the foreland area, 

resembling either splay faults off a master fault, older offset 

cross faults, or both. The manner in which merging features 

join suggests right-lateral drag along the main linear feature.

One of the offsets of the southern linear gravity anomalies coincides with the position of the main magnetic linear 

feature, thereby giving further support to a right-slip offset 

on the main linear feature.
TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

The magnetic data suggest that the main magnetic linear is a right-lateral fault in the basement rocks. The fault 

left a stronger signature to the southeast, where basement 

rocks approach the surface, than to the northwest, where 

basement rock underlies a thickening thrust plate.

One of the minor magnetic splays (faults?) crosses the 

Kalabagh fault (southwest corner of figure 3) at a low angle. 

Another minor magnetic feature also trends northwest, subparallel to, and northeast of the major inferred fault. The 

southeastern segment of the major inferred fault crosses the 

southern gravity anomaly at another of its offsets. Its central 

segment is arcuate and is near a line at the surface along 

which fold axes end or change trend. Its northwestern segment follows a segment of the Soan thrust fault that trends 

anomalously southeast. The significance of this minor magnetic splay is unclear.

SEISMIC DATA

Refraction seismic data were made available to the staff 

and students of the University of Oregon, providing them 

with a basis of some useful tectonic interpretations of a subsurface ramp (Lillie and Yousuf, 1986; Lillie and others, 

1987; Baker, 1988;Pennock, 1988;McDougallandHussain, 

1991). Because the published reproductions of these seismic 

records have lost much in detail, only some of the major features are discussed in this report. Of prime significance 

among these is the evidence of an offset of 1 km, down to the 

northwest of basement rock along the central part of the 

northwest flank of the Salt Range (Baker, 1988; Baker and 

others, 1988). This basement offset is in the same place that 

offsets are shown by the gravity and magnetic data (fig. 3). 

The inference and cause for development of a ramp structure 

in this area is thus well founded.

Earthquake seismicity provides evidence of low-magnitude ongoing activity along the Salt Range (Seeber and 

Jacob, 1977). The low magnitude of activity contrasts markedly with strong seismicity along the frontal line to the east 

in India (Quittmeyer and Jacob, 1979; Seeber and others, 

1981). This contrast in seismicity is believed by them to 

reflect a change along the Main Frontal thrust fault from 

ductile salt-bearing rocks in Pakistan to more competent 

clastic rocks in India. In the salt beds, distributed slip may 

dissipate the energy incrementally rather than forming major 

earthquakes.

POTWAR PLATEAU 

FOLD-AND-THRUST ZONE

The fold-and-thrust zone is exceptionally broad 

(180 km) in the study region and is characterized by its

well-developed lobate plan view. The zone has two 

distinctive entities, a lower structural assemblage dominated by the Salt Range rocks and structures, and an 

upper structural assemblage mainly of younger rocks 

and their characteristic open folds. These structural entities comprise a major thrust plate that overlies the Salt 

Range thrust fault (a segment of the Main Frontal thrust 

fault) and underlies the Main Boundary thrust fault 

(known locally as the Murree thrust fault). Most structural features are of Pliocene and Pleistocene age, and 

those along the Salt Range thrust fault are probably 

Holocene and, at least locally, are still active.

SALT RANGE STRUCTURES

The structural features of the Salt Range (tract Bl, fig. 

3) and of the northerly trending extensions of both ends of 

the range are dominated by salt tectonics, as illustrated by the 

series of geologic maps by Gee (1980) and summarized in 

unpublished mapping compiled by M.A Bhatti, Feroz-uddin, J.W. McDougall, P.O. Warwick, and Harald Drewes 

(1991-94). This occurrence of salt (herein generally meant 

to include gypsum and anhydrite) has affected in diverse 

ways the thrust faults, normal and reverse faults and slump 

features, all of the Salt Range-Potwar thrust plate, as well as 

the complex structures at the ends of the Salt Range. The 

characteristics of the Salt Range thrust fault particularly are 

a result of the distribution of salt.

SALT RANGE THRUST FAULT

The oldest rocks of the Salt Range are the Eocambrian 

Salt Range Formation. The Salt Range Formation consists 

of marlstone, clay, salt, anhydrite, and some siltstone and 

carbonate rocks, an assemblage that is structurally very 

incompetent and varies widely in thickness due to salt flowage. Over extensive subsurface tracts this thickness is in the 

range of many hundreds to two thousand meters thick, but 

at the surface the base of the formation is not exposed and 

so the local thickness is unknown. This formation is presumed to overlie the thick, mildly metamorphosed, and very 

competent rocks of Proterozoic age that are part of the 

Indo-Australian plate.

In a general sense, the Salt Range thrust fault separates 

the Eocambrian from the Proterozoic rocks. The presence of 

this thrust fault is inferred from abundant disharmonic structures between the plates, from the seismic refraction records, 

the seismicity data, and from the intensely deformed condition of the rocks directly above the concealed fault. In a few 

sites, segments of the Salt Range thrust fault have been 

inferred to be present, as for example along the foot of the 

range 30 km northeast of Mianwali (fig. 2). These segments
POTWAR PLATEAU REGION STRUCTURES

likely represent only subordinate structures to those in the 

nearby subsurface, although their local stratigraphic throw is 

large. Even if other, larger, subhorizontal faults are found in 

the nearby subsurface, they may be segments or splays of a 

master fault that is obliterated because of salt flowage. 

Although ductile deformation would prevail, shear planes 

would probably occur in the nonsaline rocks from which salt 

may have flowed; those fault segments likely would end 

against masses of salt accumulation, in which erratic flowage features would prevail. It is also possible that segments 

of extensive discrete fault planes exist at the base of the Salt 

Range Formation where the greatest contrast in structural 

strength of the rocks occurs. In either case, the Salt Range 

thrust fault emplaces Eocambrian (younger) rocks upon Proterozoic (older) rocks.

Faults of such distributive characteristics are cartographically difficult to illustrate. Conventionally, a standard 

fault line is used, and this has been done in nearly all the published maps and structure sections of the Salt Range, including those of figure 3 in this report. Pennock (1988) tries to 

convey the concept of distributed movement along a wide 

fault zone through the use of a dotted heavy line placed 

within the Salt Range Formation, a scheme I have restricted 

to depicting high-angle faults intruded by salt-bearing rock.

The Salt Range thrust fault underlies surficial deposits 

near the southeastern front of the Salt Range, where its precise position remains unknown. Beneath these deposits, but 

still near the surface, seismic evidence shows that the fault 

dips moderately steeply north-northwestward down to a 

depth of a few kilometers (Baker, 1988; Pennock, 1988). 

There, the fault flattens to dips of only a few degrees and 

extends beneath most of the Salt Range, where the Salt 

Range Formation (probably the zone of distributive shear or 

flowage) is 1-2 km thick.

Beneath the northwest flank of the Salt Range, the dip 

of the Salt Range thrust fault (or Salt Range Formation) 

steepens again and the contact at the top of Proterozoic basement rock drops about 1 km. The Salt Range thrust plate is 

ramped across this step in the basement. The position of this 

ramp is shown in figure 3 by the seismic anomaly line, S, 

and its closely associated gravity anomaly line, G. These 

anomaly lines appear to slightly diverge in the west where 

the seismic data ends, perhaps reflecting the distribution of 

masses of the Salt Range Formation of diverse thickness 

near the basement offset.

Northwest of the concealed structural ramp, the Salt 

Range thrust fault flattens again and dips a few degrees 

northwest. In the eastern part of the study area, the existence 

and position of this part of the fault is known as far northwestward as the axis of the Soan syncline. Deep seismic 

profiles were either not made over the western part of the 

fault or were not available to us.

STRUCTURAL IMPLICATIONS FROM THE 

STRATIGRAPHIC RECORD

Stratigraphic data along the Salt Range, from southwest 

to northeast, provide some information on early structural 

development of the region (fig. 4). The sequence of Permian 

through Cretaceous map units (fig. 4, a) are systematically 

truncated to the east by an unconformity (fig. 4, b). A westward tilting of the beds during Late Cretaceous or earliest 

Paleogene time is indicated by these geologic relationships. 

Possibly this tilting reflects the uplift of the advancing orogenic front of the western part of the main Himalayan 

tectonic lobe.

Paleogene formations are also erosionally truncated in 

the eastern Salt Range (fig. 4, c). This higher unconformity 

separates the Paleogene units from overlying Neogene units. 

This unconformity implies a renewed encroachment of the 

Himalayan tectonic lobe and the consequent uplift of the 

region northeast of the Potwar region, possibly involving the 

early stages of development of the Nanga Parbat syntaxis 

(fig- 5).

Both the upper Paleogene unit, PEC, and the lower Neogene unit, Nr, thicken in the central part of the Salt Range 

(fig. 4, d) and thin to the east and west. This thickening of 

deposits may be due to a sag in this part of the floor of these 

basins, a feature that may reflect reactivation of fault movement along a major basement structure and consequent loss 

of salt through outward or upward flowage.

The Eocambrian Salt Range Formation (eCs) and 

Cambrian Jhelum Group (Cj) thicken east of a position 

along the Salt Range near longitude 73° (fig. 4, e). Too little 

is known of the thickness of these sequences to the east of the 

study area to draw inferences from these thickness changes. 

However, all the occurrences of salt shown on the maps of 

Gee (1980), plus the major salt deposit at Kalabagh, are west 

of this site of thickness change. Possibly, then, the part of the 

Salt Range west of site e marks a more central segment of 

the original salt basin.

The distribution of major salt deposits along the Salt 

Range may reflect variations in structural controls. Known 

large salt deposits are shown on figure 4 as S and known or 

inferred small deposits as S. The small size of these deposits 

is only inferable through the absence of major mining operations in them, a situation that may reflect nongeologic factors as well as actual deposit size. These "small" deposits are 

between longitudes 72° 15' and 72°45'. Both to the east and 

west of this cluster of small salt deposits, and beyond a gap 

of 15', are the large salt deposits, respectively, of Khwera 

and Warchha. The small salt deposits are generally coextensive with the inferred sag in the Paleogene (ftc) and Neogene (Nr) basins of sedimentation.

In the basement rocks, the major right-slip fault 

believed to be shown by offsets in geophysical data along a 

northwest-trending line, crosses the Salt Range near longitude 72°30' (figs. 3 and 4, f). That fault may have influenced
10 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

-M-

-S- 

.-GEXPLANATION

Contacts

Major, young, depositional basin

Major older basins, combined In Salt Range 

separates tracts Bl from B2a and B2b

Faults Showing relative importance by line weight.

Thick lines, faults separating tectonic zones; medium 

lines, faults separating tectonic subzones; thin lines, 

faults within subzones. Dotted where extensively 

concealed. Dashed where projected outside of study 

area

Normal fault Ball and bar on downthrown side 

Thrust fault Sawteeth on upper plate 

Strike-slip fault Arrows show relative movement 

Geophysical structures Mainly features of basement

Magnetic anomaly line; arrows show likely offset 

along an inferred fault

-yFolds Showing direction of plunge. Dashed where 

projected outside of study area

Anticline

Overturned anticline1 

Syncline

Overturned syncline1 

Direction of tectonic transport

1 In places, fold inclination shown to fit tectonic pattern, rather 

than as shown on some geologic source maps. Overturned fold 

symbols on the source maps do not always conform with symbols 

used by the U.S. Geological Survey. By so doing, however, I also 

run the risk of introducting errors. Held checking is recommended 

before these data are put to further use.

Figure 3 (above and facing). Tectonic map of the Potwar Plateau and adjacent areas, showing fold tracts A-C and their subtracts 1,2,2a, and 2b. Geology adapted from unpublished geologic 

mapping compiled by M.A Bhatti, Feroz-ud-din, J.W. McDougall, 

P.D. Warwick, and Harald Drewes (1991-94).

INDUS RIVER 

(KALABAGH) SYNTAXIS
72*30'

POTWAR PLATEAU REGION STRUCTURES

73°00'

11

73*30'

JHELUM RIVER 

(HAZARA) SYNTAXIS

FORELAND

100 KILOMETERS
12 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

WEST

7T30' 72°00' 72°30' 73°00'

EAST

73°30'

-Ns-

 Nr

PEC

Unit thick/ 

Unit thin.

PEm

Erosional truncation of unit Unconformities

Inferred

tilting Unconformities

b

Metasedimentary 

rocks of Sargodha? Fractured rock, 

reactivated 

movement?

Figure 4. Diagrammatic longitudinal profile of the Salt Range, Pakistan, showing selected stratigraphic and lithologic features. Horizontal 

bars show distribution and relative thickness of stratigraphic units used on the geologic map of the Salt Range region (Gee, 1980); heavy 

wavy lines show unconformities and disconformities, dashed where control is poor; S, major salt deposit; S, minor salt deposit; a-f are discussed in the text. Stratigraphic unit symbols are as follows: Ns, Soan Group (Neogene); Mr, Rawalpindi Group (Neogene); PEC, Chharat 

Group (Paleogene); PEITI, Makerwal Group (Paleogene); KJs, Surgar Group, upper part (Cretaceous and Middle Jurassic); Js, Surgar 

Group, lower part (Middle and Lower Jurassic); ~6m, Musa Khel Group (Triassic); Pz, Zaluch Group (Upper and Lower Permian); Pn, Nilawan Group (Lower Permian); Cj, Jhelum Group (Cambrian); eCs, Salt Range Formation (Eocambrian); and pC, unexposed metamorphic(?) rock (Precambrian) probably like that exposed near Sargodha, 40 km southeast of site f.

subsequent development of overlying geologic features. The 

deepest part of the salt basin is centered over the zone of 

crustal weakness marked by the basement fault. Additionally, fracturing of overlying rocks may have been caused by 

minor reactivation along the fault. This fracturing facilitated 

upward movement of the salt. Consequently, upward-flowing salt masses were generally small near the basement fault 

and large farther from that fault, where faults ended upward 

and salt plugs merged. The tectonic transport direction and 

amount were such that the southeastward thrust faulting of 

rocks of the Salt Range thrust plate during Neogene and 

younger time did not offset the underlying parts from the 

overlying parts of this zone of weakness.

SLUMP FEATURES

The rocks of the southeastern flank of the Salt Range 

are extensively modified by slump features. The many short 

segments of thrust faults and high-angle faults shown on the

maps of Gee (1980) are mainly structures related to this 

extensive slumping. They include bits and pieces of the sole 

fault of individual slump or slide masses, pull-apart features, lateral tear faults, trapdoor structures, and reverse 

faults on local ramps. All are shallow and short; some may 

have had various kinds and phases of movement on them as 

they were gradually transferred from Salt Range crest pullaparts to listric normal faults at mid-slope and to remnants 

of low-angle normal faults lower on the slopes. The larger 

slump features are apparent from the topographic maps, 

because the general "heal-down" movement has generated 

stair-step landforms. Where the "treads" of these steps are 

sufficiently large, they provide enough flat land and, perhaps, richer soil due to entrapped alluvium, to allow for a 

few fields or a farming village.

vv There is a general gradation in slump structure, topography, and coherency of rock masses from their site of origin to their ultimate resting place near the foot of the range. 

Along the range crest, where most rocks are flat lying or
POTWAR PLATEAU REGION STRUCTURES 13

gently dipping, the beds are cut by normal faults that have 

offsets of moderate amounts. Displacement amounts dwindle north of the range crest. Other normal faults crossing 

spurs or generally parallel to cliff faces in the more resistant 

caprock are arcuate in plan, concave downslope, and in section concave down. Still other faults along the crest are rectilinear in plan, and they also commonly delineate blocks in 

the initial phase of downslope migration. While some of the 

faults that trend northerly into the terrane beyond the range 

crest may have originated through another process, these, 

and likely all the other faults were formed or were modified 

by initial breakup of the rocks down the Salt Range front. 

Salt and gypsum involvement increases downslope, where 

intrusive pods of salt and gypsum are more abundant. Various shale and marl units that alternate with Paleozoic-Paleogene limestone and dolomite facilitate this slumping 

process at all topographic levels.

The extensive slumps of the Salt Range front obscure 

the deeper-seated larger faults. Slump terranes must be 

delineated so that the remaining structures can be evaluated 

for tectonic patterns they may show. This delineation was 

made, using chiefly LANDSAT photography and the geologic maps of Gee (1980), as part of unpublished geologic 

mapping of the Potwar Plateau (compiled by M.A Bhatti, 

Feroz-ud-din, J.W. McDougall, P.D. Warwick, and Harald 

Drewes 1991-94).

SALT TECTONICS AND STEEP FAULTS

Masses of clay, marl, gypsum, and salt that have been 

injected or that have flowed are common among the rocks 

along the front of the Salt Range and its lateral extensions 

along adjacent syntaxes. The injected masses exposed on the 

frontal slope of the range or in relatively small canyons (perhaps only a hundred meters or so deep) are likely to be mingled with slump features; probably the recognition of the 

injected masses will depend on identification of layered rock 

that is steeply dipping because of upward flowage of clay, 

marl, gypsum, and salt.

Salt plugs are more readily identified in the deep canyons, where the intruded masses not only have tracts of steep 

layering and highly contorted layering of many kinds of rock 

derived mainly from the Salt Range Formation, but also have 

incorporated blocks from adjacent formations and from rare 

intrusive Cretaceous or Paleogene(?) "trap rock," or andesitic basalt.

Large evaporite masses are commonly covered by a 

veneer of clay and marl that includes not only solution-feature remnants but also colluvium and small slump masses. 

Despite the high local relief in these rugged canyons, it is 

very difficult to judge which exposures are in place and 

which are superficial. In a way the question is moot, for such 

salt masses have probably been mobile almost continually 

since they were overloaded by overlying deposits. That

mobility varied in process and rate of flowage in fully gradational ways.

Several of the large canyons trend either northeast or 

northwest, making an orthogonal pattern that is likely to have 

been initiated through tectonic stresses in the Salt Range 

thrust plate. Inevitably, salt flowage utilized these zones of 

weakness and, in time, modified the faults. Modifications of 

faults include aligned plugs of Salt Range Formation injected 

along the faults, and particularly at fault junctions.

The large cross fault that trends northeast through the 

town of Choa Saiden Shah (figs. 2 and 3) is shown by Gee 

(1980) to have the teeth of a thrust fault, which change position from the northwest side of the fault northeast of the town 

to the southeast side of the fault southwest of the town. 

Apparently, this is meant to convey the concept of a fault that 

is essentially a reverse fault with slight rotational 

development about a horizontal axis near the town. This 

rotation most likely reflects adjustment of movement along 

the fault to continued compressional deformation; there 

could be a tendency to develop thrust or reverse faults high 

in the plate (to the northeast) and to respond more to salt flowage, with normal faults, low in the plate (to the southwest).

STRUCTURES AT THE ENDS OF THE SALT RANGE

At its eastern and western ends, the Salt Range trends 

more northerly and seems to merge gradually with the structures of Jhelum and Indus River syntaxes (figs. 3 and 5). 

Data from published maps (Kazmi and Rana, 1982) and from 

field observations at these sites suggest that the trend of 

faults and folds in the Salt Range also change. In detail, the 

structural features reflect a local change in orientation of the 

compressive stress system from one directed to the southsoutheast to fields of east-southeast- (Jhelum end) and southwest- (Indus end) directed movement. The combination of 

features along the range length gives the impression that the 

Salt Range thrust plate moved forward (south-southeast) and 

upward and, upon reaching a very shallow level at which lateral confinement ended, flared out laterally.

A sigmoidal bend of the east end of the range is accompanied by diverse orientations of fold axes that serve as 

guides to orientation of local compressive stress. In part, the 

structural story is revealed through maps of Gee (1980) and 

through the regional map of Kazmi and Rana (1982); more 

detailed study shows that some modifications may be made 

to the map. For example, the Salt Range Formation is not 

thrust upon the alluvium of the Bunha River which flows 

through the gap (fig. 3) in the sigmoidal bend. Also, the 

Pabbi Hills (fig. 3) are probably separated from the rocks at 

the sigmoidal bend by a splay fault off the Salt Range thrust 

fault, because the stress fields under which local deformation 

occurred in the separate areas are about 80 degrees apart. The 

abrupt change in strike and dip and in rock types across the 

Bunha River gap (Gee, 1980; figs. 2 and 3) are not
14 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

compatible with the inference that the Salt Range thrust fault 

follows the eastern base of the hills of the sigmoidal bend, 

nor are these features simply drag structures near a concealed 

strike-slip fault. Spot mapping at the southeastern tip of the 

sigmoidal belt illustrates a more substantial involvement of 

salt tectonics in the enigmatic bend than shown by Gee 

(1980).

Provisionally, I suggest that a second splay of the Salt 

Range thrust fault lies beneath the broad alluvial bottom of 

the lower part of the Bunha River. This second splay, and 

other branches from it, join the exposed and inferred thrust 

faults of Paleozoic units over the upper Siwalik Group northeast of the Bunha River gap. Orientation of fold axes in the 

upper platelet of this thrust fault are north-northeast; those in 

the underlying platelet trend northeast; and those in the 

lowest platelet (all three platelets are part of the Salt Range 

thrust plate) trend east-northeast. It is this systematic counterclockwise rotation of local transport direction that suggests 

the lateral flaring out of this edge of the Salt Range thrust 

plate. Further explanation of the complexities of the Bunha 

River gap and the southern tip of the sigmoidal bend are 

deferred to a time when the entire area is remapped in detail.

The western end of the Salt Range forms the northeast 

side of the Indus River syntaxis. A right-slip fault, the Kalabagh fault, forms one or perhaps two straight segments of 

this end of the Salt Range (McDougall and Khan, 1990). 

Small lobes of complexly disturbed rocks alternate with 

these straight segments. To the north, the Kalabagh fault 

merges successively with several thrust faults that trend west 

and southwest beyond the extent of the study area, where the 

faults swing south around the syntaxis. To the southeast, the 

Kalabagh fault may also merge with the Salt Range thrust 

fault (Gee, 1980). A final observation is that one of the magnetic anomalies is subparallel to the central part of the Kalabagh fault.

The Kalabagh fault is a transform structure that enables 

the fold-and-thrust zone to move far forward in the Potwar 

Plateau region. McDougall and Khan (1990) infer a lateral 

offset of 12-14 km on this fault from displaced piercing 

points. I suggest that this right-slip fault was modified to a 

right-oblique ramp at a northeast-facing step in the basement, also recognized by McDougall and Khan (1990), and 

that the small lobes of deformed rock extending southwest of 

the Kalabagh fault are high-level flaps that spilled over parts 

of the ramp with, of course, assistance from salt tectonism. 

Heavy surficial slumping affects rocks in these lobes but not 

along the traces of the Kalabagh fault. This, then, is the support for a southwestward flaring ouUrf the highest structural 

level of the Salt Range thrust plate.

POTWAR PLATEAU STRUCTURES

The Potwar Plateau is a broad, slightly uplifted, and 

thus slightly incised basin that is characterized by gently

folded Neogene deposits of an early stage of development of 

the foreland basin. These rocks comprise the upper part of the 

Salt Range thrust plate, and they overlie the Paleogene and 

older rocks exposed around three sides of the plateau and 

exposed in a few places within it. Although these rocks were 

compressively deformed along with the entire plate, deformation in the Neogene rocks was less severe than it was in 

the underlying Paleogene rocks. This decrease in deformation intensity indicates that the Neogene rocks may postdate 

some of the deformation and also that they were transported, 

piggyback-fashion, on the lower rocks.

The following analyses of structural features of the Potwar Plateau is developed mostly from geologic and geophysical maps. It is therefore considered to supplement, rather 

than dispute published analyses derived mainly from seismic 

profiles and "admissible" balanced cross sections (Leathers, 

1987; Jaume and Lillie, 1988; Pennock, 1988; McDougall 

and Hussain, 1991). Both approaches offer styles of 

disciplined speculation. Such support as is available for the 

map-approach comes mostly from the field and that for the 

section-approach from models. Moreover, both styles of tectonic analysis contain elements of the other style, and they 

both generate an understanding of the development of a complex region.

SUCCESSOR FORELAND BASINS

A basinal aspect of the Potwar Plateau is made apparent 

by the annular distribution of the base of the Neogene deposits and by their general inward dip. These deposits are mainly 

sand, silt, and clay; conglomeratic sand is less common than 

other sediments and thin beds of volcanic ash are scarce. The 

basin is elongate east-northeast, with the central structural 

axis referred to as the Soan syncline. A western segment of 

this axis is labeled Soan syncline extension (fig. 3) with the 

intent of avoiding the implication that a simple fold was offset by an as yet undiscovered fault that may be associated 

with the minor magnetic anomaly. Alternatively, the synclines may be separate en echelon structures. The flanks of 

the syncline or synclines mostly dip no more than 10° 

inward, rarely as much as 20°.

The Potwar region may already have developed as a 

foreland depositional basin during Paleogene time; this basin 

subsequently was incorporated into the fold-and-thrust zone 

through compressional structural overprinting. This early 

depocenter position is suggested by the thick deposits of the 

upper Paleogene Rawalpindi Group in the northern part of 

the plateau. The Rawalpindi Group is several kilometers 

thick, but thins markedly to the southeast away from its depocenter. The depocenter axis of the Rawalpindi basin shifted 

southeastward between the earlier depositional phase and a 

later depositional phase of the pale-brown and yellowishgray Siwalik Group, which also is several kilometers thick. 

Another southeastward shift in the depocenter axis is
POTWAR PLATEAU REGION STRUCTURES 15

Plate- convergence 

direction

N

Trace of plate boundary

Frontal line (sawteeth on upper plate) 

\ I Fold and thrust zone

>cal direction of tectonic transport 

Shingled thrust zone 

6t^-^__^ Orogenic bulgeOriginal 

horizontal

STAGE 1 

MIOCENE MIOCENE ^^^-^

N, NANGA PARBAT SYNTAXIS 

MMT, MAIN MANTLE THRUST FAULT

Figure 5 (above and following two pages). Block diagram series showing developmelent of syntaxes in three stages, Miocene-Holocene.

indicated by the presence of the Holocene alluvial basins 

along the Indo-Gangetic plains southeast of the Potwar Plateau study area.

All basin deposits of the Potwar region are mainly 

clastic; silt and sand are dominant, but grit and conglomerate are abundant at some horizons and probably increase in 

abundance northward. The strong red color of the 

Rawalpindi Group rocks, particularly the widespread Murree Formation, may reflect a red rock provenance in the 

form of shale of Jurassic to Paleogene ages, which lay farther north. With a southeastward advancing frontal line, the 

rocks of the older foreland basins were caught up in that 

deformation, raised, and eroded; erosional products from 

the early basins were consequently deposited in the 

successor foreland basins. Gradually the red color was lost, 

perhaps reflecting an environment favoring the spread of 

reducing conditions in the last half of the Neogene, or the 

loss of red source-rock provenance.

FOLDS

Folds are the dominant structural feature in the foldand-thrust belt. The abundance, size, and economic affiliation of folds varies in three fold tracts, labeled on figure 3.

Tract B2a, to the southwest, is characterized by having 

only a few folds. These are mostly short in length, have 

small amplitude, and vary in trend. These few folds are 

mainly in the northern and eastern part of the tract near the 

more highly deformed terranes. No oil fields are in tract 

B2a, apparently as a result of the absence of fold traps. A 

weak magnetic-anomaly line separates tract B2a from tracts 

B2b and B2c.

Tract B2b, to the east, has many large folds that form a 

systematic lobate pattern, concave to the northwest. Individual folds are long, have amplitudes measurable in hundreds 

to a few thousand meters, and some are doubly plunging. A 

few thrust faults cut some of these folds, which may be local
16 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

VERTICAL 

PULL-APART

Upward-moving

granite bodies (mainly 

emplaced after local 

thrust faulting)

STAGE 2 

MIOCENE-PLIOCENE

N, NANGA PARBAT SYNTAXIS 

J, JHELUM RIVER (HAZARA) SYNTAXIS 

MBT, MAIN BOUNDARY THRUST FAULT 

MMT, MAIN MANTLE THRUST FAULT
POTWAR PLATEAU REGION STRUCTURES 17

Salt Range

STAGE 3

PLIOCENE - HOLOCENE

N, NANGA PARBAT SYNTAXIS 

J, JHELUM RIVER (HAZARA) SYNTAXIS 

I, INDUS RIVER (KALABAGH) SYNTAXIS 

P, POTWAR PLATEAU

MFT, MAIN FRONTAL FAULT 

MBT, MAIN BOUNDARY FAULT 

MMT, MAIN MANTLE FAULT
18 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

disharmonic warps in local upper plates. Some of these folds 

are believed to have formed over offsets in the basement 

rocks (Pennock, 1988, p. 25). Most of the oil fields, including the largest fields of the region, are in tract B2b, possibly 

because the fold-trap conditions were optimum for oil collection and retention.

Tract B2c, to the north, has both large and small folds 

that also make a lobate pattern, but concave to the north. 

These folds are generally tighter than those of the other 

tracts, and some of them are inclined to the south. They are 

vergent to the south despite some fold symbols used on 

unpublished geologic mapping (compiled by M.A Bhatti, 

Feroz-ud-din, J.W. McDougall, P.O. Warwick, and Harald 

Drewes, 1991-94), and they are believed to be genetically 

related to thrust faults. More folds in tract B2c are cut by 

subparallel thrust faults than are the folds in tract B2b. Small 

oil fields are in a few of the anticlines. Possibly, other B2c 

folds are unfavorable for oil accumulation because fold traps 

were ruptured by the faults

The stronger folding of tract B2c seems to coincide 

both with the presence of thicker Rawalpindi Group rocks 

and with greater distance from the frontal line. These relations suggest that the folds of tract B2c are older and (or) 

longer lived than those of tracts B2a and B2b. These 

observations of moderately intense deformation are compatible with the proximity to the much more intense deformation above the Main Boundary thrust fault.

THRUST FAULTS

The abundance and size of thrust faults in the fold-andthrust zones increase from tracts B2a through B2c, as do the 

abundance and size of the folds. The only thrust fault in tract 

B2a is in the extreme northwest part of the tract, where the 

northwest end of the Kalabagh fault merges with the structurally highest thrust fault, or splay, off the Main Frontal 

thrust-fault system. There, the narrow continuation of the 

locally wide fold-and-thrust zone is cut by a thrust fault that 

also swings from an easterly trend to a southerly one parallel 

to the underlying structure.

That this northwestern part of tract B2a is underlain by 

a thrust fault precisely in the part of the tract having a few 

folds suggests that these folds may be disharmonic upon the 

basal thrust fault. Conceivably, then, the subsurface leading 

edge of the basal thrust fault may project across tract B2a 

along the western ends of the few folds of the tract, not far 

from the major magnetic linear feature. Some of the folds of 

this tract may be cored by blind sled-runner thrust faults generated along the salt beds. (This term "sled-runner fault" 

describes a thrust fault that is extensively subhorizontal, 

commonly following a weak unit, and then near its leading 

edge curves upward, crossing beds.) Johnson and others 

(1986) and Pennock (1988) offer some comparable 

interpretations.

The rocks and folds of tract B2b are cut by five thrust 

or reverse faults, of which four are directed southeastward 

and the middle one is directed northwestward, as a backthrust (fig. 3). Fault 1, in the southeastern corner of tract 

B2b, is a splay off one of the branches of the Main Frontal 

thrust fault system (Salt Range thrust fault), and it has little 

offset. Fault 2 appears to be very steep to the west, to merge 

with the northwest-trending scissors fault at Choa Saiden 

Shah, and then branch out into a thrust-fault zone to the east. 

The backthrust fault, 3, cuts at least one fold and dies out to 

the southwest. Faults 4 and 5 merge to the southwest and are 

truncated by the Soan thrust fault to the northeast at sites a 

few kilometers apart. Several folds overlie fault 5 and apparently are truncated by that fault or, more likely, are disharmonic above it where fault 5 forms a minor lobe.

Tract B2c contains many thrust faults that are geometrically and genetically closely tied to the tight folds, and the 

tract itself is bounded below and above by thrust faults. The 

underlying Soan thrust fault may be a through-going 

structure because previously mapped faults can be linked 

across covered areas. It is a thrust fault of moderate displacement, as judged by the fact that the Soan thrust fault separates tracts of diversely oriented folds. A central segment of 

the Soan thrust fault forms a flap or lobe, similar to the Salt 

Range frontal fault, but in miniature. However, displacement 

on the Soan thrust fault need not be large, for it typically juxtaposes two units of the Siwalik Group.

Thrust faults within tract B2c suggest conditions gradational to those in the shingled thrust zone northwest of (on the 

upper plate of) the capping Main Boundary thrust fault. Most 

of the faults in tract B2c are probably steep; some merge with 

folds, and others truncate folds, requiring at least moderate 

amounts of displacement. These thrust faults were probably 

formed at deeper levels than were the faults in the other 

tracts, a tectonic relationship common to many orogens.

Further evaluation of faults of the fold-and-thrust zone 

is hampered by the apparent absence of notations of dips on 

faults in the primary geologic map sources. It is also 

thwarted by lack of first-hand access to the seismic profiles 

known to exist at least in tract B2b (Pennock, 1988, fig. 3) 

and across the Kohat Plateau just west of the study region 

(McDougall and Hussain, 1991, fig. 6), and by lack of access 

to some key drill-hole data.

Estimates on the amount of tectonic transport that has 

taken place across the eastern part of the area, from the Soan 

syncline to the frontal line south of the Pabbi Hills, range 

from 13-50 km (Pennock, 1988, p. 37; Sarwar and DeJong, 

1979; Baker, 1988). An additional 45±15 km of shortening 

took place in the northern part of the Pot war Plateau (Baker, 

1988, p. 83).

Paleomagnetic studies in the Salt Range-Potwar Plateau 

have led to diverse interpretations of rotation of various rock 

masses at various times. Not all of the interpretations are in 

agreement on timing of such rotations (Crawford, 1974; 

Klootwijk, 1979; Opdyke and others, 1979; Pennock, 1988).
POTWAR PLATEAU REGION STRUCTURES 19

There is agreement, however, that rotation was counterclockwise and occurred at least periodically between about 9 

and 0.7 Ma, with amounts of rotation totalling 30°^5°. The 

rotation is probably related to the development of the syntaxes near the Salt Range-Potwar Plateau region, and basically is a response to the forward (southward) developing 

plate systems in the region of the western or northwestern 

margin of the subducting Indo-Australian plate.

SHINGLED THRUST-FAULT ZONE

The ranges north of the Main Boundary thrust fault, 

including the Kala Chitta, Attock-Cherat Range, Hazara and 

Gandghar Mountains, and the Margala Hills, show a moderately ductile style of deformation in which thrust faults are 

closely interleaved in moderately to tightly folded rocks. 

Much of this zone is underlain by Proterozoic to Mesozoic 

rocks, although, locally, some Miocene Rawalpindi Group 

rocks are also infolded. The Main Boundary thrust fault separates the shingled thrust-fault zone from the underlying 

fold-and-thrust zone; the northern margin of the zone is 

about 100 km to the north, far beyond the margin of the study 

area. Within the study area the shingled-thrust-fault zone has 

two major thrust plates distinguished mainly by their markedly different rock types and metamorphic condition and 

also by their internal structures.

LOWER THRUST PLATE

The Margala Hills and much of the Kala Chitta Range 

(fig. 3) are underlain chiefly by unmetamorphosed Mesozoic 

and Paleogene rocks, which are warped into discontinuous 

tight folds and which are cut by many thrust faults. These 

rocks consist of alternating thick-bedded limestone units that 

typically weather to form rugged cliffs and shale and marlstone units that weather to form topography of low relief, 

thereby accentuating the weathering characteristics of the 

mechanically stronger carbonates. The less competent rocks 

commonly are the sites of the thrust faults.

In the eastern part of the study area, the basal fault is 

known as the Murree thrust fault (or fault zone) and in the 

west part of the area other terms have been applied; all are 

part of the extensive Main Boundary thrust fault, which separates thick remnants of foreland basin deposits from older, 

deeper-seated rocks and thin remnants of foreland basin 

deposits. In the Potwar Plateau region, this fault forms parts 

of two lobes that merge laterally about 40 km west of Attock 

City (fig. 3). The fault plane there dips steeply northward, 

and it is presumed to flatten gradually downdip to the north. 

Little data have been obtained from this fault, probably 

because it is in shale and thus is poorly exposed.

The faults and folds within this zone vary widely. Most 

folds are inclined southward but a few are inclined

northward, and they vary in amplitude and length. In many 

places folds have faulted axial planes. Most faults dip steeply 

northwest or are vertical. Folds in the Margala Hills commonly are strongly inclined to the southeast and locally are 

nearly recumbent.

Near the Indus River the trend of the lower thrust plate, 

underlying Main Boundary thrust fault, and many of its 

internal faults and folds change direction and thereby separate two minor tectonic lobes, concave to the north (east of 

the Indus River) and northwest (west of the river). This 

tectonic pattern seems to mimic, on a small scale and early 

stage of development, the syntaxes.

The direction of inclination of folds shown on unpublished geologic map sources used in this study must be used 

with caution. The use of standard map symbols is erratic. 

Many of the symbols implying northward overturning could 

be cartographic errors rather than interpretive errors. The 

reconnaissance restraints of the present project prevented 

field checking of the geometry of many such folds, but Yeats 

and Hussain (1987, fig. 8) verify the dominant presence of 

south inclinations.

UPPER THRUST PLATE

North of, and tectonically above, the plate of sedimentary rocks is a thrust plate of Proterozoic metasedimentary 

rocks. These plates are separated from each other by a major 

upended part of the Panjal thrust fault (fig. 3), which also has 

several local names, such as the Natiagali fault. To the east, 

there are two faults which could be the continuation of the 

Panjal thrust fault. I favor the southern fault to be the Panjal 

thrust fault because it separates Proterozoic rocks from the 

underlying younger rocks in a more consistent manner.

The Proterozoic rocks are mainly clastic, comprising 

argillitic rocks, subgraywacke, slaty shale and siltstone, and 

phyllite. Rocks are mostly metamorphosed to the greenschist 

facies, but in places they reach the amphibolite facies. At 

some places, limestone or marble sheets are intercalated in 

the clastic rocks either through primary deposition, tectonic 

interleaving, or infolding. Where these are present, some 

control on internal structure is offered by slaty cleavage. Of 

the several Proterozoic formations mapped, only the Hazara 

Slate (or phyllite) is dated, as 740±20 and 730±20 Ma 

(Crawford and Davies, 1975). That age substantiates the relative ages implied by the observed Hazara clasts in the overlying Cambrian Abbotabad Formation northeast of the study 

area (Latif, 1974).

In the Attock-Cherat Range (fig. 3) some limestone 

units are mapped as thrust-faulted slivers and some of these 

bounding faults are mapped as tightly folded (Yeats and 

Hussain, 1987). Such complications are not recorded farther 

east in the Hazara and Gandghar Mountains, but cannot be 

entirely denied in those mountains because so little of them 

has been mapped in detail (or published?).
20 TECTONICS OF THE POTWAR PLATEAU REGION, DEVELOPMENT OF SYNTAXES, PAKISTAN

In summary, the style of deformation of the shingled 

thrust-fault zone shows effects of deeper burial than the 

rocks to the south in more distal parts of the orogen, and 

thus of greater subsequent uplift and erosion. Ductile deformation was at least locally intense, and metamorphism generally increases northward in rocks raised from deeper 

structural levels.

TECTONIC DEVELOPMENT

The structural changes across the Potwar Plateau area 

reflect a systematic variation in the stage of their tectonic 

development, coupled with less systematic variations in the 

distribution of rocks of differing mechanical strength. 

Although most tectonic events recorded in the study area are 

part of the Himalayan orogeny, a few events and features 

predate that orogeny. Speculations on these early events may 

demonstrate their subsequent influence.

PRE-HIMALAYAN TECTONIC 

DEVELOPMENT

The dating of the deformation of the Proterozoic rocks 

of the Indo-Australian plate is uncertain from a local perspective. The apparent lateral restriction of salt and gypsum 

in the Salt Range Formation suggests an Eocambrian structural control of a closed basin or perhaps a rift in which the 

brine was concentrated.

For most of Paleozoic time, the local geologic record is 

very scarce; perhaps a Pangean land mass was being assembled. Toward the end of the time of Pangean existence, the 

local records involving the Permian Tobra Formation and its 

underlying surface record conditions of nearby high relief, 

cold climate, and glaciation. Cobbles and boulders in outwash conglomerate resemble rocks found in granitic plutons 

of northwestern India, but because of their great distance 

from the Salt Range and the subsequent convergence of Salt 

Range outcrops with the Indian plutons, those plutons are not 

a likely source of the coarse clasts. Conceivably, the scattered large magnetic highs of the Salt Range area mark the 

sites of similar plutons, and these may have contributed to 

the Tobra while they were some distance farther southeast.

From regional data, Pangea then broke up about 200 Ma 

(Pavoni, 1985) and, with the northward movement of the 

Indo-Australian plates (initially separate plates(?) and ultimately one plate), the Tethyan seaway narrowed. The collision of the India part of the northward-moving plate with the 

Eurasian plate began about 100 Ma (Treloar and others, 1991). 

A narrow Tethys seaway lasted in the study area at least to 

Eocene time, although marine and nonmarine conditions fluctuated throughout the Paleogene. Himalayan tectonic activity 

during this time was centered far to the north of the study area 

and is not recorded in the local sedimentation.

HIMALAYAN OROGENIC EVENTS

The forward spread of the southern flank of the Himalayan orogen into the Potwar Plateau region was first 

recorded by the unconformity between Paleogene and Neogene rocks. The systematic truncation of underlying rocks 

indicates that the area was uplifted. From the evidence of 

subsequent deposition of coarse clastic rocks, this uplift was 

related to widespread orogenic activity. Apparently, the 

unconformity marks the spread of the main Himalayan tectonic lobe to the southwest. This event may also have been 

linked to an early stage of development of the Nanga Parbat 

syntaxis (fig. 5, stage 1) along the trace of the northwestern 

edge of the subducting Australo-Indian plate.

Molasse of the Rawalpindi Group was deposited on the 

truncated Paleogene and older rocks of the Neogene foreland 

basin. At that time, the Main Boundary thrust fault may have 

been the frontal fault, and the Panjal thrust fault and others 

were also probably active. The Jhelum River syntaxis was 

forming in the rocks beneath the Main Boundary thrust fault 

(fig. 5, stage 2).

Before the end of the Miocene the compressive stress 

field spread farther south and, accordingly, the foreland 

basin shifted farther south to collect the Siwalik Group. Concurrently, the deformation affected the rocks of the Rawalpindi Group, which were compressed into an early stage of a 

fold-and-thrust belt and were uplifted, eroded, and partly 

recycled into the new basin. Compressive deformation of the 

rocks north of the Main Boundary thrust fault intensified and 

deeper-level features and rocks were eventually brought to 

the surface.

As the stress field propagated still farther south, the 

older part of the Siwalik Group was, in turn, folded over a 

basal detachment or decollement that followed approximately the interface of Paleozoic bedded rocks with the 

basement crystalline rocks of the Indo-Australian plate. 

Where this decollement encountered the salt- and gypsumbearing part of the Salt Range Formation, fault propagation 

advanced more rapidly than it did elsewhere, forming the 

lobate pattern of the Potwar Plateau. Salt tectonics developed, or intensified, particularly along the basal fault, along 

the step-like offset of the top of the basement rocks, and 

along the various steep faults abutting the decollement. 

Deformation in the ranges north of the Main Boundary thrust 

fault ended before 2.8 Ma (Yeats and Hussain, 1987), and 

deformation in the Salt Range may not have begun before 0.7 

Ma (Yeats and others, 1984).

Over large tracts of the plateau, the Siwalik Group 

rocks were probably piggy-backed upon the underlying 

more competent bedded rocks. In a few places, north-facing 

steps in the upper surface of the basement rocks caused the 

upper plate material to form a ramp or a local reverse fault 

(reviewed in detail by Baker, 1988). The Salt Range thrust 

fault propagated ahead of the site of deposition of the 

younger part of the Siwalik Group and raised rocks from the
REFERENCES 21

lower part of the plate to a high position. Locally, at the eastern and western corners of the new frontal line, laterally 

unconfmed stress fields brought about some lateral thrust 

faulting, which produced the sigmoidal bend in structural 

features and topography at the eastern end of the Salt Range 

and the anomalously oriented folds at both ends of the range. 

Counterclockwise rotation of the plate also took place near 

the frontal line between about 9 and 0.7 Ma, in adjustment to 

the plates' wrapping around the west edge of the descending 

Indo-Australian plate. Younger blind thrust faulting may be 

developing beneath the anticline at Lilla.

At the same time, the Potwar Plateau region continued 

to be deformed by a combination of compressive stress (generally oriented north-northwest south-southeast), salt tectonics, and uplift. Siwalik Group rocks were eroded, along 

with older rocks, and all were accumulated in the youngest 

depocenter of the Indo-Gangetic plains. The Main Boundary 

thrust plate did not cease its southward movement before 1.8 

Ma (Yeats and Hussain, 1987). A right-lateral fault in the 

basement rock appears to have been reactivated. Pleistocene 

beds were locally tilted and faulted, and further uplift and 

erosion occurred across the entire study area. By this time, 

at least 16 km of cover was removed from the northern 

ranges (Opdyke and others, 1979) to reveal their greenschist 

and, locally, more intense grade of metamorphism. Near the 

center of the plateau, about 4 km of cover was removed and 

perhaps slightly more over the Salt Range. The Indus River 

syntaxis was growing (fig. 5, stage 3), and nearby thrust 

faulting took place as recently as 0.6 Ma (Khan, 1983).

Some reversal of faulting and possibly extensional tectonism occurs along the south side of the Peshawar basin and 

perhaps along the southeast flank of the Gandghar Mountains 

(fig. 3). This suggests that the internal or intramontane basin 

formed by extension, concurrently with compressive deformation still in progress along the present frontal line. Such 

a diverse stress field probably reflects the presence of highly 

ductile conditions near the decollement beneath these areas.

The tectonic development continues. The frontal line 

may be expected to migrate forward as a new ramp is 

encountered by a decollement fault extension to the southsoutheast, probably propagating along a weak horizon 

beneath the recent alluvial deposits and, as yet, unnoticed at 

the surface. Faults along the south side of the Peshawar 

basin are seismically active; the few normal faults along the 

foothills north of the Attock-Cherat Range, however, show 

the basin-ward block to be rising rather than settling, so the 

tectonic picture in that area is not fully clear.

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Pakistan Oil and Gas Development Corporation (OGDC) 

report, 17 p., 7 maps.

 1971, Report on gravity survey of western limits of Basal El 

L Bannu Plain Mianwali depression, Parhal area and regional 

gravity traverse in part of Kohat Potwar Foredeep, west of 

Indus River, Punjab and NWFP Provinces: unpublished Pakistan Oil and Gas Development Corporation (OGDC) report, 21 

p., with tables and maps.

Waheed-ud-din, and Lotyshev, V.I., 1970, Report on gravity survey 

of Basal E/L area, District Campbellpur, West Pakistan: 

unpublished Pakistan Oil and Gas Development Corporation 

(OGDC) report, 23 p., 7 maps.

Yeats, R.S., and Hussain, Ahmad, 1987, Timing of structural events 

in the Himalayan foothills of northwestern Pakistan: Geological Society of America Bulletin, v. 99, no. 8, p. 161-176.

Yeats, R.S., Kahn, S.H., and Akhtar, Mohammad, 1984, Late Quaternary deformation of the Salt Range of Pakistan: Geological 

Society of America Bulletin, v. 95, no. 8, p. 958-966.

Published in the Central Region, Denver Colorado 

Manuscript approved for publication January 11, 1995 

Edited by Craig Brunstein 

Graphics and Photocomposition by Mari L. Kauffmann

OU.S. GOVERNMENT PRINTING OFFICE: 1995-673-046/86124
SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS

Periodicals

Earthquakes & Volcanoes (issued bimonthly). 

Preliminary Determination of Epicenters (issued monthly).

Technical Books and Reports

Professional Papers are mainly comprehensive scientific reports 

of wide and lasting interest and importance to professional scientists and 

engineers. Included are reports on the results of resource studies and of 

topographic, hydrologic, and geologic investigations. They also include 

collections of related papers addressing different aspects of a single scientific topic.

Bulletins contain significant data and interpretations that are of 

lasting scientific interest but are generally more limited in scope or geographic coverage than Professional Papers. They include the results of 

resource studies and of geologic and topographic investigations; as well 

as collections of short papers related to a specific topic.

Water-Supply Papers are comprehensive reports that present significant interpretive results of hydrologic investigations of wide interest 

to professional geologists, hydrologists, and engineers. The series covers 

investigations in all phases of hydrology, including hydrology, availability of water, quality of water, and use of water.

Circulars present administrative information or important scientific information of wide popular interest in a format designed for distribution at no cost to the public. Information is usually of short-term interest.

Water-Resources Investigations Reports are papers of an interpretive nature made available to the public outside the formal USGS publications series. Copies are reproduced on request unlike formal USGS 

publications, and they are also available for public inspection at depositories indicated in USGS catalogs.

Open-File Reports include unpublished manuscript reports, maps, 

and other material that are made available for public consultation at depositories. They are a nonpermanent form of publication that may be cited in other publications as sources of information.

Maps

Geologic Quadrangle Maps are multicolor geologic maps on topographic bases in 7 1/2- or 15-minute quadrangle formats (scales mainly 1:24,000 or 1:62,500) showing bedrock, surficial, or engineering 

geology. Maps generally include brief texts; some maps include structure 

and columnar sections only.

Geophysical Investigations Maps are on topographic or planimetric bases at various scales, they show results of surveys using geophysical techniques, such as gravity, magnetic, seismic, or radioactivity, which 

reflect subsurface structures that are of economic or geologic significance. Many maps include correlations with the geology.

Miscellaneous Investigations Series Maps are on planimetric or 

topographic bases of regular and irregular areas at various scales; they 

present a wide variety of format and subject matter. The series also includes 7 1/2-minute quadrangle photogeologic maps on planimetric 

bases which show geology as interpreted from aerial photographs. The 

series also includes maps of Mars and the Moon.

Coal Investigations Maps are geologic maps on topographic or 

planimetric bases at various scales showing bedrock or surficial geology, 

stratigraphy, and structural relations in certain coal-resource areas.

Oil and Gas Investigations Charts show stratigraphic information for certain oil and gas fields and other areas having petroleum potential.

Miscellaneous Field Studies Maps are multicolor or black-andwhite maps on topographic or planimetric bases on quadrangle or irregular areas at various scales. Pre-1971 maps show bedrock geology in relation to specific mining or mineral-deposit problems; post-1971 maps 

are primarily black-and-white maps on various subjects such as environmental studies or wilderness mineral investigations.

Hydrologic Investigations Atlases are multicolored or black-andwhite maps on topographic or planimetric bases presenting a wide range 

of geohydrologic data of both regular and irregular areas; the principal 

scale is 1:24,000, and regional studies are at 1:250,000 scale or smaller.

Catalogs

Permanent catalogs, as well as some others, giving comprehensive 

listings of U.S. Geological Survey publications are available under the 

conditions indicated below from USGS Map Distribution, Box 25286, 

Building 810, Denver Federal Center, Denver, CO 80225. (See latest 

Price and Availability List.)

"Publications of the Geological Survey, 1879-1961" may be purchased by mail and over the counter in paperback book form and as a set 

microfiche.

"Publications of the Geological Survey, 1962-1970" may be purchased by mail and over the counter in paperback book form and as a set 

of microfiche.

"Publications of the U.S. Geological Survey, 1971-1981" may be 

purchased by mail and over the counter in paperback book form (two 

volumes, publications listing and index) and as a set of microfiche.

Supplements for 1982, 1983, 1984, 1985, 1986, and for subsequent years since the last permanent catalog may be purchased by mail 

and over the counter in paperback book form.

State catalogs, "List of U.S. Geological Survey Geologic and Water-Supply Reports and Maps For (State)," may be purchased by mail and 

over the counter in paperback booklet form only.

"Price and Availability List of U.S. Geological Survey Publications," issued annually, is available free of charge in paperback booklet 

form only.

Selected copies of a monthly catalog "New Publications of the 

U.S. Geological Survey" is available free of charge by mail or may be obtained over the counter in paperback booklet form only. Those wishing a 

free subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 National Center, Reston, VA 22092.

Note.-Prices of Government publications listed in older catalogs, 

announcements, and publications may be incorrect. Therefore, the prices 

charged may differ from the prices in catalogs, announcements, and publications.