--- title: "Lithology of Lesser and Tethys Himalaya; Siwalik difference" subject: "Engineering Geology I" chapter: 7 key: "semester_3/engineering_geology_i:lithology-of-lesser-and-tethys" source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/lithology-of-lesser-and-tethys site: BCT Engineering --- # Lithology of Lesser and Tethys Himalaya; Siwalik difference Engineering Geology I · Chapter 7: Geology of Nepal - Asked in: 2079 Bhadra, 3+2 marks - Video: [Subdivisions of Himalayas: TransHimalaya, Greater Himalaya, Lesser Himalaya, Shivalik with Animation](https://www.youtube.com/watch?v=er9fqvm1Qcs) — Zeta Axis (UPSC-SSC) - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/lithology-of-lesser-and-tethys - Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-7 ## Question Describe the lithological characteristics of the Lesser and Tethys Himalayan zones. Highlight a major lithological difference between the Siwalik and Higher Himalaya. ## Short answer The Lesser Himalaya has low-grade slate, phyllite, quartzite, limestone, marble (Nawakot, Kathmandu Complexes) and granites. The Tethys Himalaya comprises Cambrian-Cretaceous fossiliferous marine limestone, shale, sandstone, weakly metamorphosed. The key difference: Siwalik is young, soft, poorly consolidated sedimentary rock; Higher Himalaya is old, hard, high-grade metamorphic and granite. ## Answer #### Lesser Himalaya **Lithology** - **Nawakot Complex:** slate, phyllite, quartzite, limestone, dolomite and metasandstone. Lower Nawakot Group: Kuncha, Fagfog, Dandagaon, Nourpul and Dhading formations; Upper Nawakot Group: Benighat, Malekhu and Robang formations. - **Kathmandu Complex (nappe):** the **Bhimphedi Group** of schist, quartzite and marble (Raduwa, Bhainsedobhan, Kalitar, Chisapani, Kulekhani and Markhu formations), overlain by the **Phulchauki Group** of slate, sandstone and limestone (Tistung, Sopyang, Chandragiri, Chitlang and Godavari formations). - **Granite and gneiss bodies:** Palung granite and other granites, and the Ulleri augen gneiss. **Structure:** intensely folded, faulted and thrust. There are synclinoria (e.g. the Mahabharat synclinorium of the Kathmandu nappe) with klippen, and anticlinoria, with many thrusts and tectonic windows. The beds mostly dip northward. #### Tibetan-Tethys Himalaya **Lithology:** Cambrian to Cretaceous (and Eocene) marine sedimentary rocks, rich in fossils: limestone, shale, sandstone, slate, quartzite and marl; the Thakkhola graben has Neogene sediments. The famous ammonite fossils (shaligram) of the Kali Gandaki valley come from Jurassic shale. **Structure:** a thick sedimentary pile, unmetamorphosed or weakly metamorphosed, folded (open to tight folds) and thrust in places, and cut by later normal faults (Thakkhola graben). #### Major lithological difference: Siwalik vs Higher Himalaya | Point | Siwalik | Higher Himalaya | |---|---|---| | Rock type | Sedimentary (sandstone, mudstone, conglomerate) | High-grade metamorphic (gneiss, schist, migmatite) and granite | | Age | Miocene to Pleistocene (young) | Precambrian to early Palaeozoic (old) | | Consolidation | Soft, poorly consolidated | Hard, crystalline | | Fossils | Mammal and plant fossils | None (metamorphosed) | ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What are the Tibetan-Tethys Himalayan rocks? A. High-grade gneiss and migmatite B. Cambrian to Cretaceous marine sedimentary rocks rich in fossils C. Quaternary alluvium D. Siwalik conglomerate Answer: B. Tethys rocks are fossil-rich marine sediments such as limestone, shale, sandstone and marl. (Key point: Tethys lithology) 2. Where do the shaligram ammonite fossils come from? A. Jurassic shale of the Kali Gandaki valley B. Siwalik sandstone C. Higher Himalaya gneiss D. Terai alluvium Answer: A. Famous ammonites (shaligram) of Kali Gandaki come from Jurassic shale in the Tethys zone. (Key point: Shaligram) 3. What is the major lithological difference between Siwalik and Higher Himalaya? A. Siwalik is high-grade metamorphic; Higher Himalaya is sedimentary B. Siwalik is young soft sedimentary; Higher Himalaya is old hard crystalline metamorphic and granite C. Both are sedimentary but of different colour D. Both are igneous Answer: B. Siwalik is young, poorly consolidated sedimentary rock while the Higher Himalaya is old, crystalline metamorphic rock and granite. (Key point: Siwalik vs Higher Himalaya rock type) 4. Why do Higher Himalayan rocks lack fossils, unlike the Siwalik? A. They are too young B. They have been metamorphosed C. They are volcanic D. They are underwater Answer: B. High-grade metamorphism destroyed any fossils, whereas Siwalik sediments contain mammal and plant fossils. (Key point: Fossils) ## Related in Engineering Geology I - [Discontinuities; Siwalik and Higher Himalaya lithology](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Adiscontinuities-siwalik-and-higher-himalaya) — Engineering Geology I, chapter 7 - [Lithology of Higher Himalaya and Tethys zone](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Alithology-of-higher-himalaya-and) — Engineering Geology I, chapter 7, asked 3× - [Physiographic division; Siwalik and Higher Himalaya](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aphysiographic-division-siwalik-and-higher) — Engineering Geology I, chapter 7 - [Lesser Himalaya zone in detail](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Alesser-himalaya-zone-in-detail) — Engineering Geology I, chapter 7 - [Soil and rock types of Himalayan zones](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Asoil-and-rock-types-of) — Engineering Geology I, chapter 7 - [Tectonic zones and major discontinuities](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Atectonic-zones-and-major-discontinuities) — Engineering Geology I, chapter 7, asked 2× ## Related in other subjects - [Problems of Higher and Tethys Himalaya](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Ahigher-tethys-problems) — Engineering Geology II, chapter 2 - [Problems of Siwalik and Higher Himalaya](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Asiwalik-higher-himalaya-problems) — Engineering Geology II, chapter 2, asked 2× - [Problems of Lesser Himalaya and Terai](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Alesser-himalaya-terai-problems) — Engineering Geology II, chapter 2, asked 5× - [Problems of Lesser Himalaya with mitigation](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Alesser-himalaya-problems) — Engineering Geology II, chapter 2, asked 5×