Fig 2: The earth at the Permian-Triassic boundary.
The opening of the Neotethys separates the Cimmeridian
Superterrane from Gondwana.
Based on Stampfli and Borel (2002) and Patriat and Achache
For a more modern paleo-geographic reconstruction of the same
period, see this web-site
(Stampfli et al.)
Fig 4: The northward drift of India from 71 Ma ago to present
Note the simultaneous counter-clockwise rotation of
Collision of the Indian continent with Eurasia occurred at
about 55 Ma.
Source: www.usgs.org (modified)
Fig 5: Geologic - Tectonic map of the Himalaya, modified after Le
Fig 6: Geological Map of the northwest Himalaya, compiled after the
work of: Epard et al. 1995; Frank et al. 1997; Fuchs and Linner,
1995; Guntli, 1993; Herren, 1987; Kelemen et al. 1988; Kündig,
1988; Patel et al. 1993; Searle et al. 1988, 1997; Spring, 1993;
Steck et al. 1993; Steck et al. 1998; Stutz, 1988; Thöni, 1977;
Vannay, 1993; Vannay and Graseman 1998; Wyss 1999 and completed
with personal observations by Dèzes (1999). for references, see
HHCS: High Himalayan Cristalline Sequence; ISZ: Indus Suture
Zone; KW: Kishtwar Window; LKRW: Larji-Kulu-Rampur Window; MBT:
Main Boundary Thrust; MCT: Main Central Thrust; SF: Sarchu Fault;
ZSZ: Zanskar Shear Zone.
(Download map in PDF
Fig 7: Simplified cross-section of the north-western Himalaya
showing the main tectonic units and structural elements by Dèzes
The geology of the Himalaya
is a record of the
most dramatic and visible creations of modern plate tectonic
forces. The Himalayas, which stretch over 2400 km between the
Barwa syntaxis in Tibet and the
Parbat syntaxis in Pakistan, are the
result of an ongoing orogeny — the result of
a collision between two continental tectonic plates.
was formed by huge
tectonic forces and sculpted by unceasing denudation processes of
. The Himalaya-Tibet region is virtually the
water tower of Asia
: it supplies freshwater for
more than one-fifth of the world
, and it accounts for a quarter of the global
. Topographically, the
belt has many superlatives: the highest rate of uplift (nearly
10 mm/year at Nanga
Parbat), the highest relief (8848 m at Mt.
Chomolangma), among the highest erosion rates at 2–12 mm/yr,
the source of some of the greatest rivers and the highest
concentration of glaciers outside of the
feature earned the Himalaya its name, originating from the Sanskrit
for "the abode of the snow".
The making of the Himalaya
During Late Precambrian
and the Palaeozoic
, the Indian sub-continent, bounded to
the north by the Cimmerian
, was part of Gondwana
was separated from Eurasia
by the Paleo-Tethys Ocean
(Fig. 1). During that
period, the northern part of India was affected by a late phase of
the so-called "Cambro-Ordovician Pan-African event", which is
marked by an unconformity between Ordovician
continental conglomerates and the
intrusions dated at around
500 Ma are also attributed to this event.
In the Early Carboniferous
, an early
stage of rifting developed between the Indian continent and the
Cimmerian Superterranes. During the Early Permian
, this rift
into the Neotethys
ocean (Fig. 2). From
that time on, the Cimmerian Superterranes drifted away from
Gondwana towards the north. Nowadays, Iran, Afghanistan and Tibet are partly made up
of these terranes.
In the Norian
(210 Ma), a major rifting
episode split Gondwana in two parts. The Indian continent
became part of East Gondwana, together with Australia and Antarctica.
However, the separation of East and West
Gondwana, together with the formation of oceanic crust, occurred
later, in the Callovian
(160-155 Ma). The
Indian plate then broke off from Australia and Antarctica in the
(130 - 125 Ma) with the
opening of the "South Indian Ocean" (Fig. 3).
In the Upper Cretaceous (84 Ma), the Indian plate began its very
rapid northward drift covering a distance of about 6000 km ,
with the oceanic-oceanic subduction continuing until the final
closure of the oceanic basin and the obduction
of oceanic ophiolite
onto India and the beginning of
starting at about 65 Ma in the Central Himalaya. The change of the
relative speed between the Indian and Asian plates from very fast
18-19.5 cm/yr to fast 4.5 cm/yr at about 55 Ma is
circumstantial support for collision then. Since then there has
been about 2500 km
of crustal shortening and rotating of India by 45° counterclockwise in Northwestern Himalaya to 10°-15° counterclockwise in North Central Nepal relative to Asia (Fig. 4).
While most of the oceanic crust
"simply" subducted below the Tibetan block during the northward
motion of India, at least three major mechanisms have been put
forward, either separately or jointly, to explain what happened,
since collision, to the 2500 km of "missing continental crust
". The first mechanism
also calls upon the subduction of the Indian continental crust
below Tibet. Second is the extrusion or escape tectonics mechanism
(Molnar and Tapponier, 1975) which sees the Indian plate as an
indenter that squeezed the Indochina
out of its way. The third proposed mechanism is that a large part
(~1000 km (Dewey et al. 1989) or ~800 to ~1200 km) of the
2500 km of crustal shortening was accommodated by thrusting
and folding of the sediments of the passive Indian margin together
with the deformation of the Tibetan crust.
Even though it is more than reasonable to argue that this huge
amount of crustal shortening most probably results from a
combination of these three mechanisms, it is nevertheless the last
mechanism which created the high topographic relief of the
Major tectonic subdivisions of the Himalaya
One of the most striking aspects of the Himalayan orogen is the
lateral continuity of its major tectonic elements. The Himalaya is
classically divided into four tectonic
units that can be followed for more than 2400 km along the
belt (Fig. 5 and Fig. 7) .
- The Subhimalaya forms the foothills of
the Himalayan Range and is essentially composed of Miocene to Pleistocene
molassic sediments derived from the erosion
of the Himalaya. These molasse deposits, known as the Muree and
Siwaliks Formations, are internally folded and imbricated.
Subhimalaya is thrust along the Main Frontal Thrust over the
Quaternary alluvium deposited by the rivers coming from the
Himalaya (Ganges, Indus, Brahmaputra and others), which demonstrates that the Himalaya
is still a very active orogen.
- The Lesser Himalaya (LH) is mainly formed by Upper Proterozoic to lower Cambrian detrital sediments from the passive Indian
margin intercalated with some granites and acid volcanics (1840± 70
Ma). These sediments are thrust over the
Subhimalaya along the Main Boundary Thrust (MBT). The Lesser
Himalaya often appears in tectonic
windows (Kishtwar or Larji-Kulu-Rampur windows) within the High
Himalaya Crystalline Sequence.
- The Central Himalayan Domain, (CHD) or High Himalaya, forms the
backbone of the Himalayan orogen and encompasses the areas with the
highest topographic relief. It is commonly separated into four
- The High Himalayan Crystalline Sequence, HHCS (approximately 30
different names exist in the literature to describe this unit; the
most frequently found equivalents are Greater Himalayan Sequence,
Tibetan Slab and High Himalayan Crystalline) is a 30-km-thick,
medium- to high-grade metamorphic sequence of metasedimentary rocks
which are intruded in many places by granites of Ordovician (~ 500
Ma) and early Miocene (~ 22 Ma) age. Although most of the
metasediments forming the HHCS are of late Proterozoic to early Cambrian age, much younger metasediments can also
be found in several areas (Mesozoic in the Tandi syncline and
Warwan region, Permian in the Tschuldo slice, Ordovician to
Carboniferous in the Sarchu Area). It is now generally accepted
that the metasediments of the HHCS represent the metamorphic equivalents of the sedimentary
series forming the base of the overlying Tethys Himalaya. The HHCS
forms a major nappe which is thrust over the
Lesser Himalaya along the Main Central Thrust (MCT).
- The Tethys Himalaya (TH) is an approximately 100-km-wide
synclinorium formed by strongly folded and imbricated, weakly
metamorphosed sedimentary series.
Several nappes, termed North Himalayan Nappes have also been
described within this unit. An almost complete stratigraphic record
ranging from the Upper Proterozoic to the Eocene is preserved
within the sediments of the TH.
Stratigraphic analysis of these sediments yields important
indications on the geological history of the northern continental margin of the Indian
continent from its Gondwanian evolution to its continental
collision with Eurasia. The transition between the generally
low-grade sediments of the Tethys Himalaya and the underlying low-
to high-grade rocks of the High Himalayan Crystalline Sequence is
usually progressive. But in many places along the Himalayan belt,
this transition zone is marked by a major structure, the Central
Himalayan Detachment System (also known as South Tibetan Detachment
System or North Himalayan Normal Fault) which has indicators of
both extension and compression (see ongoing geologic
studies section below).
- The Nyimaling-Tso Morari Metamorphic Dome, NTMD: In the Ladakh
region, the Tethys Himalaya synclinorium passes gradually to the
north in a large dome of greenschist to
eclogitic metamorphic rocks. As with the HHCS, these
metamorphic rocks represent the metamorphic equivalent of the
sediments forming the base of the Tethys Himalaya. The Precambrian
Phe Formation is also here intruded by several Ordovician (~480 Ma)
- The Lamayuru and Markha Units (LMU) are formed by flyschs and olistholiths
deposited in a turbiditic environment, on
the northern part of the Indian continental slope and in the adjoining
Neotethys basin. The age of these sediments ranges from Late
Permian to Eocene.
- The Indus Suture Zone (ISZ) (or Indus-Yarlung-Tsangpo Suture
Zone) defines the zone of collision between the Indian Plate and
the Ladakh Batholith (also Transhimalaya or Karakoram-Lhasa Block)
to the north. This suture zone is formed by:
- :*the Ophiolite Mélanges, which are composed of an
intercalation of flysch and ophiolites from the Neotethys oceanic
- :*the Dras Volcanics, which are relicts of a Late Cretaceous to
Late Jurassic volcanic island arc and
consist of basalts, dacites, volcanoclastites, pillow lavas and minor radiolarian cherts
- :*the Indus Molasse, which is a
continental clastic sequence (with
rare interbeds of marine saltwater sediments) comprising alluvial fan, braided
stream and fluvio-lacustrine
sediments derived mainly from the Ladakh batholith but also from
the suture zone itself and the Tethyan Himalaya. These molasses are
post-collisional and thus Eocene to post-Eocene.
- :*The Indus Suture Zone represents the northern limit of the
Himalaya. Further to the North is the so-called
Transhimalaya, or more locally
Ladakh Batholith, which corresponds essentially to an
active margin of Andean type.
Widespread volcanism in this volcanic arc was caused by the melting of the
mantle at the base of the Tibetan
bloc, triggered by the dehydration of
the subducting Indian oceanic crust.
Future of the Himalaya
Over periods of 5-10 million years, the plates will probably
continue to move at the same rate. In 10 million years India will plow
into Tibet a further 180 km. This is about the
width of Nepal.
Because Nepal's boundaries are marks on the Himalayan peaks and on
the plains of India whose convergence we are measuring, Nepal will
technically cease to exist. But the mountain range we know as the
Himalaya will not go away.
This is because the Himalaya will probably look much the same in
profile then as it does now. There will be tall mountains in the
north, smaller ones in the south, and the north/south width of the
Himalaya will be about the same. What will happen is that the
Himalaya will have advanced across the Indian plate and the Tibetan
plateau will have grown by accretion
the few clues about the rate of collision between India and Tibet
before the GPS measurements were made was the rate of advance of
Himalayan sediments across the Ganges
There is an orderly progression of sediments in front
of the foothills. Larger boulders appear first, followed by
pebbles, and further south, sand-grains, silts, and finally very
fine muds. This is what you see when you drive from the last hills
of the Himalaya southward 100 km. The present is obvious, but
the historical record cannot be seen on the surface because the
sediments bury all former traces of earlier sediments. However, in
drill holes in the Ganges plain, the coarser rocks are always on
the top and the finer pebbles and muds are on the bottom, showing
that the Himalaya is relentlessly advancing on India.
Ongoing geologic studies
There are many areas of geologic research being conducted in the
Himalaya. Until recently only the area controlled by Nepal was
readily accessible to geologists while Tibet, India, and Pakistan
were relatively unexplored by western scientists.
Once such area of research is the basic structure of the Himalaya.
Following finding of shear sense in both the top-north
(extensional) and top-south (compressional) along the South Tibet
Detachment (the fault that separates the Greater Himalayan
Crystalline and Tethyan Himalaya), several models came forward to
explain this including gravity collapse, erosional-controlled
upwelling, tectonic wedge, as well as many others. Conclusively
resolving the origin of the Greater Himalayan Crystalline as well
as the nature of the South Tibet Detachment to the point of
scientific consensus is dependent on further study.
A closely related problem to that of the STD, is the inverted
metamorphism, sometimes referred to as the inverted metamorphic
sequence (IMS) which is a metamorphic sequence where higher
temperatures and pressures are found to increase with structural
height. It is located between the LHS and the GHS, generally
somewhat associated with the MCT. Various authors have suggested
kinematic models (where a regular sequence was deformed), thermal
models (where there actually was a source of heat above the IMS),
and mixtures of the two to explain it.
Localized geology and geomorphology topics for various parts of the
Himalaya are discussed on other pages:
This paleogeographic reconstruction is mainly based on the papers of Besse et al. (1984), Patriat and Achache (1984), Dewey et al. (1989), Brookfield, (1993) Ricou (1994), Rowley (1996) and Stampfli et al. (1998). More information can be found on this website.
The fourfold division of Himalayan units has been used since the work of Blanford and Medlicott (1879) and Heim and Gansser (1939).
- Besse J., Courtillot V., Pozzi J.P., Westphal M., Zhou Y.X.,
(1984): Palaeomagnetic estimates of crustal shortening in the
Himalayan thrusts and Zangbo Suture.: Nature (London), v. 311,
- Blanford W.T., Medlicott H.B., (1879): A manual of the geology
of India: Calcutta.
- Brookfield M.E., (1993): The Himalaya passive margin from
Precambrian to Cretaceous times: Sedimentary Geology, v. 84,
- Dewey J.F., Cande S., Pitman III W.C., (1989): Tectonic
evolution of the Indian/Eurasia Collision Zone: Eclogae geologicae
Helvetiae, v. 82, no. 3, p. 717-734.
- Dèzes, p. (1999): Tectonic and metamorphic Evolution of the
Central Himalayan Domain in Southeast Zanskar (Kashmir, India).
Mémoires de Géologie (Lausanne) No. 32.
- Heim A., Gansser A., (1939): Central Himalaya; geological
observations of the Swiss expedition 1936.: Schweizer. Naturf.
Ges., Denksch., v. 73, no. 1, p. 245.
- Molnar P., Tapponnier P., (1975): Cenozoic tectonics of Asia;
effects of a continental collision.: Science, v. 189,
- Patriat P., Achache J., (1984): India-Eurasia collision
chronology has implications for crustal shortening and driving
mechanism of plates.: Nature, v. 311, p. 615-621.
- Ricou L.M., (1994): Tethys reconstructed: plates, continental
fragments and their Boundaries since 260 Ma from Central America to
South-eastern Asia: Geodinamica Acta, v. 7, no. 4,
- Stampfli G.M., Mosar J., Favre P., Pillevuit A., Vannay J.-C.,
(1998): Permo-Triassic evolution of the westernTethyan realm: the
Neotethys/east-Mediterranean basin connection: Peri Thetys, v.
- Steck A., Spring L., Vannay J.-C., Masson H., Stutz E., Bucher
H., Marchant R., Tièche J.C., (1993): Geological Transect Across
the Northwestern Himalaya in eastern Ladakh and Lahul (A Model for
the Continental Collision of India and Asia): Eclogae Geologicae
Helvetiae, v. 86, no. 1, p. 219-263.