Karakoram-Hindukush Tectonostratigraphic Basin:

This basin represented the southern edge of the Asian Plate prior to the collision of the continents.A large-scale deformation has brought together several slivers of geological formations, which originally belonged to a separate geographic and geologic entity. To define Karakoram or Hindukush stratigraphically is a difficult job, especially in the terminal areas of the geographic borders.
         The word Karakoram is the most commonly used term by workers engaged in the northern most areas of Pakistan. They have included most of these areas in the Karakoram. Even a substantial part of the Hindukush is included in the Karakoram with the plea that geological boundaries overlap geographic boundaries and vice versa. Several times, the boundaries of the two ranges have been defined, revised and redefined. However, working boundaries are always there, as for example, Desio (1979) defined the bordersof Karakoram in the following words.
        The term “Karakoram mountain belt” most commonly refers to the bundle of mountain
ranges located between the upper Yark and and upper Indus River to the north and south respectively,
and between the upper Shayok and the western divide of the upper Hunza River to the east and west
respectively, between these limits, the Karakoram Range is about 600 km long, with an average
width of 150 km. Four of its peaks exceed 8000 m; one of these is K2 (8611 m), which is the second
highest peak in the world.
        Other workers in the region bring its western limit up to Trich Mir fault or include Chitral
fault as the western limit, northwest of which is undisputed Hindukush. Similar situation prevails in
the central part of the Karakoram, where workers feel that geology of other mountain ranges is easily
mixed with Karakoram. To give an example, the statement of Kravchenko (1979) is recorded here,
who categorically stated, “The Tien Shen, Pamir and Karakoram are situated in different mountain
belt systems, they resemble each other in their regional structure. In all three mountain belts the
geosyncline and subsequent orogeny become younger toward the south, reflecting the consolidation
of the Eurasian continental massif, and its collision with the Indian plate, as the result of the
northward drift of the latter”.
        Gaetani (1997) stated that the southern geological boundary roughly coincides with the
Shayok Suture Zone, and extended it to join MKT. They added that to the west, the geological
boundary should extend beyond the geographical one drawn at the Karambar Valley. They also
added, that“The Hindu Raj Range should be included because both magmatic and sedimentary units
continue, fairly homogeneously, throughout the Yarkhun Valley”. Gactani ct al. (1997) cited that
several options are present in setting the western geological boundary. The first, followed by Searle
(1991), is to merge the geographical east Hindukush (Trich Mir included) into the western
Karakoram.This interpretation has recently been abandoned by Searlcand Khan (1996). Second, the
western boundary of the “geological' Karakoram could be set either at the Chitral fault or preferably
at theTrich Mirfault”.
        From the foregoing discussion, it can be stipulated that workers do face difficulties in
confining their geologic description to the borders of the geographic limits. Consequently, some of
them used the combine term 'Karakoram-Hindukush' to be at ease in the description of their
palaeontology and stratigraphy. This part of convenience is suitable to follow for the description and
correlation of stratigraphic units.Therefore, the stratigraphy is described under the combined
heading of Karakoram - Hindukush Tectonostratigraphic Basin. The boundaries of this
tectonostratigraphic basin are as follows: The southern limits arc marked by MKT and the northern
boundary extends into Badakhshan Province of Afghanistan but the details presented here stop at  Pak-Afghan border in the west and the Pak-China border in the east. Length wise the western
boundary crosses the border with Afghanistan and the eastern border is across K2 and extends into
Kashmir.

          Geologically, this tcctonostratigraphic basin is extremely complex. The aftermath of the

events of the collision of plates has brought disastrous effect on the stratigraphic sequences.
Workers get bewildered, when they do not find any head and tail on any stratigraphic sequence from
a montage of rocks. Talent et al. (1999) viewed the scenario of Karakoram Hindukush
Tectonostratigraphic Basin in the followingwords:“The structure of Chitral is likea scrambled deck
of cards, a montage of slivers, slabs and slices; unscrambling these would be inconceivable without
paleontologic control”. They further emphasized, “Close co-ordination of stratigraphic, structural
and palcontologic investigations is imperative, if ultimate meaning (a valid context for mineral
exploration) is to be wrung out of structurally complex areas of Phanerozoic rocks like those of the
Himalaya”.          It cannot be denied that the classification of a basin promote critical analysis of the
characteristics of sediments as wellas it provides convenience for the description of stratigraphy and
the correlation is made easy. Attempts to divide the Karakoram-Hindukush Tectonostratigraphic
Basin have been made by many workers; Gansser (1980) divided it into three units or zones. Pudscy
et al. (1985) made three units and included Kohistan island arc as their third unit and the other two
pertain to the Karakoram-Hindukush Tectonostratigraphic Basin. Their northern unit extends from
Reshun fault to the borders of Pakistan with Afghanistan. The central unit is delineated from Reshun
fault southwards to MKT. Buchroithner and Gamerith (1986) followed the same suite and finally
Gaetani(1997) made three units compatible with stratigraphic concepts.

          Making divisions of this basin is not an easy job. The presence of plutons with their

metamorphic associates appear like mushrooms all over the basin, which has marred the face of the
basin creating difficulties for clean partition to be based on different attributes of the basin. Bearing
this in mind, it is only right to say that any attempt to divide the basin has to be based on the
predominance of a certain characteristic of the basin. In view of the above-mentioned state of affairs
of the basin, it is understood that boundaries of each unit have to bear bitrary.

          Lithologically, this terranc is composed of a pelitc-psammitc-granitoid basement with

overlying pelitic and carbonate cover rocks with amphibolites followed southwards by a Palaeozoic
to Mesozoic package. The latter low-grade sediments are composed of slates and meta-greywacke
sequences overlain by a thick sequence of shelf carbonates. This sequence is intruded by the
Karakoram Axial batholith.

         The Karakoram-Hindukush Tectonostratigraphic Basin can roughly be divided into its geologically separate three component parts: the central or axial part is a granitic batholith, and forms the core of an anticlinorium. The emplacement of which parted the basin into the Northern Sedimentary Province, which contains mostly unmetamorphosed to anehimetamorphic rocks of Palaeozoic to Late Cretaceous age and the Southern Metamorphic Province predominantly composed of metamorphic rocks of Palaeozoic (or Precambrian) to Upper Tertiary. 

They are named and described in other post.plz see next post

1.Northern Sedimentary Province
2.CentralAxial Batholith
3.Southern Metamorphic Province