Abdul Wali Khan University Mardan, Dept Of Geology

1. Uzair shah
Presentation
Geology Of Pakistan
OPHIOLITIES
OPHIOLITIES IN NORTHER
PAKISTAN
AWKUM

2. OPHIOLITES
• Ophiolites are techtonicaly emplaced successions of mafic and
ultramafic rocks that are considered to represent fragments of
oceanic crust.
• An Ophiolite is a segment of oceanic crust and mantle
tectonically exposed on land by obduction (over
thrust),usually when oceanic basin closes.

3. Formation of Ophiolites
• Ophilites are fragments of oceanic crust and upper mantle
that have been uplifted and emplaced on continental margins.

4. Lithology of Ophiolites
• Ophiolites consist of five distinct
layers.

5. Tectonic Setting & Emplacment of Ophiolites

6. Emplacment Of Ophiolities
Major Mechanism
• Ophiolites are emplaced in arcs or collisional oregenes by
three major mechanisms.
 Obduction or thrusting of oceanic lithosphere onto a
passive continental margin during continental collision

7. Cont….
 Splitting on the upper part of a descending slab and
obduction of a thrust sheet onto a former arc

8. Cont….
 An addition of a slab of oceanic crust to accretionary prism in
an arc system.

9. Cont….
• The metamorphic complex at the base ofophiolites may play a
major role in ophiolite emplacement.
• These metamorphic soles, as they are often called, have many
features in common
1. Thickness generally range from 10-500 m
2. They extend laterally for tens to hundreds of kilometers
3. Most show a sharp decrease in metamorphic grade from top
to bottom

10. Ophiolite In Pakistan
• It is believe that many of the ultramafic and associated mafic
rocks in Pakistan are ophiolities for example fragments of
oceanic crust.
• The ophiolities in Pakistan occur in Different tectonic
environment.
• In Bela, Muslim Bagh, Zhob and Waziristan they are fragments
of Oceanic crust which were abducted upon the sediments of
the margin of Indo-Pakistan subcontinent.

11. Cont….
• In Ras Koh they occure in a zone with strongly deform
sediment dipping below the Chagai volcanic arc, suggesting a
subduction complex in the Ras Koh mountain range.
• The ophiolites in Northern Pakistan occur in a suture zone
between Eurasian plat and the Indo-Pakistan subcontinent.

13. Ophiolities Of Northern Pakistan
DARGAI/MALAKAND OPHIOLITIES
• The Dargai ophiolities complex, Malakand division of Pakistan
(60 km NNE of Peshawar) is in east west trending elongated
body, about 25 km long and 5 to 6 km in wide.
• According to Rossman and Abbas (1970) the Dargai Ophiolites
are presumably underlain by Paleozoic Carbonate and
overlain by Pre-Cambrian Schist.

14. Cont….
• The upper contact of ophiolite is in East West trending fault which
dip to North. Where as the lower contact is not exposed but
probably also a north dipping fault.
• Tahirkhel et al assume that the Dargai Ophiolities are tectonic
outlier of Kohistan Sequence underlain by the MMT.
• Abbas in 1970 interpreted that the Dargai ophiolite consist of
following assamblage
• Ultramafic tectonics
• Ultramafic Cumulates
• Mafic Cumulates

15. Cont….
Ultramafic Tectonics
Isolated outcrop, South-Eastern corner consist of harzbergite
(90%) and 10% dunite. Strongly foliated and lineation and small
isoclinally ore bodies.
Ultramafic Cummulates
Major rock unit in Dargai, consist of harzbergite (80%) and dunite
(20%), characterized by gently dipping layers of dunite and
chromite within harbergite.

16. Cont….
Mafic Cummulates
Highest unit in Dargai ophiolites, sheeted dyke complex and
volcanic suit are absent. Mafic Cummulates consist of gabbro
with layers of serpentine.Two type of laying are present. One is
generally subhorizontal and locally traceable for over 1.5 km. The
other layer is steeply north dipping and having foliation in scghist
north of the ophiolites.
CHROMITE
The grade of chromite in Dargai is less than 45%
In ultramafic rock occur as: dessiminated grain
In ultramafic tectonic occur as: pods
In mafic cummultes occur as : layers form

17. SHANGLA ZONE
• Most ophiolities in Northern Pakistan are related with the
Indus suture zone.
• West of the Nanga Parbat another zone appears related to the
major thrust, the Kohistan or Patan Fault. This ophiolites zone
is called the Shangla belt by Ganesser.
• Major ophiolities occurence are near Chilas and the Shangla
pass. The main part of Chilas ophiolite occur along the Indus
river.

18. Chilas Complex
• The Chilas Complex is a large body of mafic-ultramafic rocks
extending from Nanga Parbat to eastern Afghanistan.
• The Chilas Complex extends for more than 300 km between
Nanga Parbat and the Dir River, and is some 40 km widein its
central part. (M. Asif Khan, M. Qasim Jan 1989)
• Bard and others (1980) interpreted the complex as a lopolith.
• Similar rocks also occur on the eastern flank of Nanga Parbat
(Misch 1949) and in Kargil, Ladakh (Rai and Pande 1983).

21. • The Chilas Complex is a large mafic-ultramafic body closely associated
with the Kohistan Arc sequence in the western Himalaya of northern
Pakistan. The arc and the Chilas Complex occupy an area of 36,000 km2,
bounded on the north and south by major sutures.

22. • Most of the complex consists of massive (although locally
layered) gabbro-norites, which comprise variable amounts of
plagioclase (Ano+m), orthopyroxene (Ery6-4), clinopyroxene
(mg = 75-55), magnetite, ilmenite, quartz, K-feldspar,
hornblende, biotite.
• In the central part of the complex, near the base, there are
minor discordant dikes and intrusive bodies as large as 5 km2
of a dunite-peridotite-troctolite-gabbronorite-pyroxenite-anorthosite
association (UMA association)

23. • UMA association displays excellent layering, graded bedding, slump
breccias, and syndepositional faults.
• These rocks contain olivine, relatively Mg-rich orthopyroxene,
clinopyroxene (mg = 85-67), and calcic plagioclase, hornblende, chrome
spinel, pleonaste, and represent a more primitive magma batch emplaced
into the base of the gabbro-norite magma chamber.
• The mafic complex is not an ophiolite. Rocks of the complex have more
petrographic and compositional similarities with plutonic blocks from
island arcs and with other major mafic complexes such as the Border
Ranges Complex of Alaska and those from the Ivrea Zone in the Alps.

25. Jijal
Complex
• The Jijal Complex, one of the largest Neo-Tethyan ophiolites in
Pakistan, occupies a deep-level section of the Cretaceous
Kohistan Arc that was obducted along the Main Mantle Thrust
or Indus Suture Zone.
• The Jijal complex, comprising garnet granulites and alpine-
type ultramafic rocks, covers an area of more than 150 sq. km.
• The ultramafic rocks occupy the southern part of the complex
but the granulites are locally also present at their southern
margin

26. • The western and eastern limits of the complex are not known
because of the inaccessibility of the area
• It appears that to the east the rocks extend beyond the Indus
river into Hazara tribal territory whilst to the west they may
reach up to, but not beyond, the drainage divide between the
Indus and Swat valleys.

28. • The complex is fault-bounded to the north as well as the
south; it seems that it is a tectonic block or wedge bounded
by faults on all sides.
• The southern fault is an extension of the main fault separating
the Swat schists and granitic gneisses from amphibolites of
the Kohistan complex to the southwest of Jijal.
• In the Jijal-Patan area, the amphibolites occur to the
northeast of Patan and are separated from the garnet
granulites by a fault running along the approximately N-S
course of the Patan stream.

29. THE ULTRA MAFIC ROCKS
• The ultramafic rocks occur in a NW-trending, north-dipping
body over 4.5 km wide and at least 10 km long
• There are number of ultramafic bodies emplaced along the
thrust, the largest being the 7 x 1 km lensoid serpentinised
mass near Shangla.
• A number of small serpentinired bodies also occur along the
Patan stream, probably emplaced and/or squeezed
tectonically along the northern fault

30. • The rocks are hard, massive, brownish to green or grey, and
medium grained some of the pyroxenites are coarse-grained.
• There is no clear distinction of top, bottom or chilled margins.
The contacts between various units may be sharp or
gradational some of the pyroxenites contain leases of dunite
with sharp contacts.
• The J ijal ultra mafie rocks are mainly represented by
clinopyroxenites, dunites, peridotites, harzburgite and
websterites make up less than half the outcrops.

32. INDUS SUTURE OPHIOLITIES
• The ophiolities and melange section of the Westren
Himalayan in contrast to those of central Himalayan have
notbeen well studied.
• In the central Himalayan the Indus Suture ophiolite and the
ophiolitic melange nappes mark the boundary between Indian
and Eurasian plates. This boundary is traceable to the Nanga
Parbat. East of the Nanga Parbat massive Burzil ophiolites and
the Dras ophiolities have been describe by Wadia(1937)

33. Cont….
• Several large and small bodies of ultramafic rocks occurs
throughout the Dras volcanics.
• North of the bruzil-dras ophiolities occure near Skardu. They
belong to the Shyokh ophiolite belt which is the North of
Ladakh granite wheres the bruzil-dras belt id South of it.
• The two ophiolities belts can be followed north and north
westward along the eastern periphery of Nanga Parbat. In this
area the zone consist mainly of green stone complex of meta
volcanics and meta sediment.

34. Cont….
• Foliated gabbro is know to occur in the green stone complex
near Dammer Nisar, ultramafic rock are know to outcrop in
this area.

35. THANK YOU