Cenozoic deposits of Himalaya

The Outer or Sub-Himalaya is the main zone of the Cenozoic sedimentation. The Paleogene-Neogene sequences of the Sub-Himalaya occurs in the northern states of India. The Subathu, Murree and Dharamshala are the main Paleogene groups of rocks where Siwalik is a major Neogene group of Cenozoic sequences of the Sub-Himalaya. Other deposits belongs to the North-Eastern regions which are covered in other articles –

• Subathu Group : The Subathu Group is well exposed in the Subathu town in the Himachal Pradesh. It is onsists of a thick succession of conformable strata comprising of dark green and red shales interbedded with nummulitic limestones, carbonaceous shales and bands of sandstone. The group overlies the Pre-cambrian slates and limestones. The rocks are rich in fossils like foraminifera, ostracoda, molluscs and fish remains, indicating a marine environment of deposition for the group. The group is further divided into Kakra and Subathu Formations.

• Murree Group : The Subathu Group is overlain by Murree and Dharamshala groups. Both of these have same age but occurs in different regions (Murree in J&K and Dharamshala in HP). The rocks of Murree Group consists of red, maroon and purple sandstones, mudstones and shales. The base of the group is consists of conglomerates, which indicate the end of marine sedimentation and beginning of freshwater deposition in the Himalayan region. The Murree group is divided into Lower Murree and Upper Murree Formaitons.

• Dharamsala Group : It is equivalent to the Murree Group of J&K and is divided into two groups.
  • Dagshai formation (Lower Murree) comprises of alternating red, gray and purple clays with hard, green-gray coloured sandstone and red mudstones. The formation was deposited under shallow marine to terrestrial environment.
  • Kasauli formation (Upper Murree) overlies the Dagshai formaiton consists of brownish yellow and greyish green medium to coarse grained sandstones with subordinate yellowish green, grayish green and purple shales. The floral elements of the Kasauli Formation indicate moist to dry tropical environment.
  • An Upper Eocene to Lower Miocene age is assigned to the Dharamsala Group.

• Siwalik Group : Already discussed in the article click here