Introduction to salt range
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The Salt Range is a prominent geological formation in Pakistan, located south of the main Himalayan ranges, characterized by its significant rock salt deposits and rich geological features, making it a valuable site for scientific study. It exhibits excellent exposure of geological sequences from the Precambrian to the Eocene, with distinct structural styles due to tectonic activity from the Indian and Eurasian plate collision. The range is divided into eastern, central, and western sections, with vital economic resources including high-quality gypsum and globally recognized pink salt.
Introduction to salt range
- 1. Introduction: About 70 km south of the main Himalayan Ranges, the Salt Range was raised due to Main Frontal Thrust (MFT) as a 180-km-long and 85-km-wide ridge of hills at the southern edge of the Potwar Basin Pakistan. MFT, which is associated with salt range, also called Salt Range Thrust (SRT). Salt range is widest in its central part, between the Khewra and the Warchha where it also contains the best exposures of Palaeozoic and Precambrian sequences. All the strata are excellently exposed due to lack of vegetation. The quality of the exposure also provides excellent opportunities to appreciate tectonic features in the field. The Salt Range is, therefore, of international scientific and educational value, and is highly worthy of conservation and preservation. Figure 1-Fig. 1 Location map of the Salt Range in northern Pakistan
- 2. The name Salt Range was first used by Elphinston in 1808. He visited this territory (1808– 1815) and noticed the extraction of salt from the Salt Range. Hence, historically, the Salt Range derives its name after the occurrence of gigantic deposits of rock salt embedded in the Precambrian bright red marls that are stratigraphically known as the Salt Range Formation (formerly Punjab Saline Series). Apart from the easily available roadside geology, here are some prominent gorges cutting the Salt Range. Among these gorges, we have visited Khewra, Chichali, Zaluch, and Nammal gorge, which provide the fantastic locations to study the sediment Figure 2-Generalized exposed stratigraphic units with major breaks in deposition in the Salt Range, Pakistan
- 3. The Salt Range contains wealth of geological features, for which it has been rightly called as the “Field Museum of Geology.” Because it has all the sedimentary sequence right from Precambrian upto Eocene. In fact, it represents an open book of geology, where the richly fossiliferous stratified rocks such as the Permian carbonate succession contains brachiopod fauna with conodont biostratigraphy and foraminifera biostratigraphy. We also have collected different Traces and fossils of Trilobites, Bracheopods, Cephalopods, Forms, etc from the field. Salt range is divided into three parts namely eastern, central and western. At eastern side older and at western side mostly younger rocks have been exposed. In our field visit, we have studied stratigraphy of eastern, western (Salt range) and part of Trans-Indus ranges (Surghar range). ➢ EASTERN SALT RANGE (from Jogi Tilla to Nilawahan) ➢ WESTERN SALT RANGE (From Nilawahan to Warchha Mandi) ➢ CENTRAL SALT RANGE (From Warchha Mandi to Mari Indus) Economically salt range is very important for their 2nd largest salt mine in the world. large deposits of high grade Gypsum and Anhydrites, an important calcium minerals, are found Figure 3-a Schematic illustration of the three subdivisions of the Salt Range (modified after Gee and Gee 1989). b Generalized map showing major structural trends in different parts of the Salt Range
- 4. here in salt range. Beside gypsum, anhydrides and medium grade coal, pink salt of salt range is also very famous all over the world. Pakistan export pink salt of salt range to different countries of the world. Regional tectonics of the Salt Range About 50 millions years ago Indian plate collide with Eurasian plate formed the gaint Himalayas. Due compressive stresses (collision) many thrust faults were produced namely, Main Karakurrum Thrust, Main Mentle Thrust, Main Boundry Thrust and Main Frontal Thrust. Main Frontal thrust that is associated with salt range is called Salt Range Thrust. Due to SRT Salt Range were uplifted. The Salt Range is truncated along the southern margin by Salt Range Frontal Thrust (SRFT), which is bounded between Jehlum and Indus River. It has pushed the older successions of the Salt Range upon the less deformed tertiary sequences of the south lying in the Punjab Plain. The thrust zone is largely covered by Recent conglomerates and Jehlum River alluvium. However, near the Kalabagh area, the thrust is exposed and shows the Palaeozoic rocks overlying the Neogene or Quaternary deposits of the Punjab Plain. At eastern side of the salt range more older (Precambrian) rocks are exposed as compared to western (younger) salt range which shows the strength of stresses that have been applied on this area. We can also trace back the collision behavior of indo- Figure 4-Generalized regional tectonic map of the Salt Range, Pakistan (modified after Kazmi and Rana 1982)
- 5. eurasion plates collision from the folding and faults that are present in Salt Range. The Salt Range is thus the surface expression of the leading edge of the decollement thrust. Jehlum fault (left handed strike slip fault) marks eastern boundary of the Salt Range, and at western side, Kalabagh fault (Right handed strike slip fault) marks the western limit of Salt Range. The Salt Range is structurally very complex and consists of three basic structural styles: (1) compressional deformation (thrusting and folding), (2) transform deformation (strike faults), and (3) extensional deformation (normal faults). Location of Salt Range Salt Range is located in Indian plate at upper Indus basin of Pakistan, with having east west trending. Salt range is a mountain range of punjab province. Salt Range lies between the valley of Indus and Jehulum river in Punjab province of Pakistan. The range has a length of 180 km and it is highest peak is Sakesar which is approximately 1,600 m. Location of Salt Range can be defined by two ways. 1. On the basis of faults 2. On the basis of geographic view North Kala Chitta Range Potwar Basin Soan Basin Murree Thrust Salt Range Thrust Salt Range ) (central part Sargodha High Punjab Plain Karampur Well South 200 km 80 km 120 km Tertiary Rocks Mesozoic and Palaeozoic Rocks Basement Rocks Salt Range Formation Figure 5-Generalized cross section across the Potwar Basin and the Salt Range, showing Salt Range decollement (modified after Gee 1983). No vertical scale is intended
- 6. On the basis of faults NORTH: Salt Range is bounded by Main Boundary Thrust fault (MBT) from north side. SOUTH: South limit of the Salt Range is Salt Range Thrust (SRT). EAST: Eastern boundary of the Salt Range is Jehlum Fault (strike slip fault). WEST: At western side of Salt Range Kalabagh Fault (strike slip fault) is present. Figure 6-Figure 6 location of salt Range on the basis of faults. Geographical location of salt range NORTH: Salt Range lies at south of the Potwar plateau means at north of Salt Range Potwar plateau lies. SOUTH: Punjab plane is present at south of the Salt Range. EAST:Jehlum river flowing at east of Salt Range.
- 7. WEST: Mari Indus or Indus River flowing at west of Salt Range. Figure 7-location of salt range interm of geographic view