Rahul Vishwakarma (Impact of Mobile belt in Crustal evolution of India)-1.pptx

Impact of mobile belt in crustal evolution of India
Mobile belts and associated mineralisation.
Crustal thickening
Orogeny
Indian tectonic evolution
Himalayas and its evolution
Aravalli delhi mobile belt
Eastern ghat mobile belt
Central Indian tectonic zone
Pandyan mobile belt
Himalayan mobile belt
Cratons and mobile belts
Pan african orogeny

1. Impact of Mobile belts in crustal evolution of India Department of Applied Geology Dr. Harisingh Gour Vishwavidyalaya Sagar . MP Under Guidance of: Prof. A.K. Singh Department of Applied Geology Presented by: Rahul Vishwakarma M.Tech 4th Sem Reg. no. Y22251046

2. Contents Introduction Significance Major mobile belts in India Aravalli- Delhi mobile belt (ADMB) Central Indian Tectonic Zone (CITZ) Eastern Ghat Mobile belt (EGMB) Pandyan Mobile Belt (PMB) Himalayan Mobile Belt Conclusion References

3. Introduction Figure 1: Distribution of Proterozoic mobile belts in the Indian sub-continent and their relationships. Source : Research Gate DOI:10.1007/978-3-030-42845-7-4 Mobile belts are tectonically active regions characterized by frequent earthquakes, volcanic activity, and mountain building. Often associated with collision or convergence of tectonic plates. Play crucial role in the formation and evolution of continents.

4. Significance: Formation of continents : Play crucial role. Collision or convergence causes accretion of new crustal material. Creation of mountain ranges : Mobile belts are often associated with the formation of mountain ranges. Development of mineral resources : Mobile belts are often enriched in mineral resources, such as metals and gemstones. The high temperatures and pressures associated with tectonic activity can lead to the formation of mineral deposits. Understanding Earth's history : Studying mobile belts provides valuable insights into the Earth's geological history. By analyzing the rocks and structures found in mobile belts, scientists can reconstruct past tectonic events.

5. Major Mobile Belts in India Aravalli Delhi Mobile belt : One of the oldest mobile belts in India. Formation associated with the collision of Proterozoic continental blocks. Central Indian Tectonic Zone (CITZ) : It extends roughly from the Narmada River in the north to the Krishna River in the south. Eastern Ghat Mobile belt (EGMB): Geological province located along the eastern coast of India, extending from Odisha ( Brahmini river basin) in the north to Ongole (Andhra Pradesh) in the south. Pandyan Mobile Belt (PMB): Geological province located in southern India, specifically in the state of Tamil Nadu. Himalayan Mobile belt: Formation due to the collision of the Indian Plate with the Eurasian Plate. Impact on crustal evolution: uplift of the Himalayas, creation of deep thrust faults, and development of metamorphic rocks.

6. Aravalli–Delhi Mobile Belt (ADMB) In parts of Gujarat and Rajasthan of western India . NE–SW trending ~800 km long Aravalli Mountain Range represent an ancient mountain chain with well preserved records of ~3 Ga years of the Precambrian evolutionary history . Major chronostratigraphic terranes with distinct development histories and metallogenic events are represented by the Banded Gneissic Complex as the basement, the Aravalli and Delhi Supergroups as the mobile/fold belt components. Figure 2: Aravalli-Delhi mobile belt. Source : https://www.sciencedirect.com/science/article/abs/pii/S0040195100001566

7. Crustal evolutionary models Ensialic Rifting Model: One of the earliest tectonic models . Ensialic rifting 1900-2000 Ma is the reason for the formation of Large Aravalli basin followed by subsidence and crustal shortening. Another in 1700-1800 Ma favored Delhi sedimentation, followed by underplating by mantle magma, decoupling of mantle lithosphere and subduction. 1500-1700 Ma Delhi orogeny. 900-1500 Ma, Mantle lithosphere welding led tectonic exhumation of granulites . Fig 3: Ensialic rifting model Source : https://www.sciencedirect.com/science/article/abs/pii/S0040195100001566

8. C entral Indian Tectonic Zone (CITZ) The Precambrian crust of Central India consists of two Archaean cratonic domains, i.e , Bundelkhand Craton in the north and Bastar Craton in the south. Accreted along the ENE–WSW trending Central Indian Tectonic Zone (CITZ). The limits of the CITZ is defined by the Son–Narmada North Fault (SNNF) in the north and Central Indian Shear Zone (CIS) in the south. In the east, the CITZ continues into the Chotanagpur Gneissic Complex (CGGC) and further northeast into the Shilling Plateau. Figure 4: Geological map of CITZ Source : https://opengeology.in/citz-central-indian-tectonic-zone/

9. Plate Tectonic Model Southerly dipping subduction of Bundelkhand craton invoked below Bastar craton. Subduction was initiated at 2.4 Ga. Followed by closure of the Mahakoshal basin at 1.8 Ga, accompanied by calc-alkaline granitic magmatism channeled through reverse-slip ductile shear zones in a contractional tectonic regime. The amalgamated BC and BKC formed the basement for the Sausar supracrustal rocks. Subduction system was culminated with the continent–continent collision. Fig 5: a . Neoproterozoic collision between two micro-continents the present day Satpura Mobile Belt and the Bastar craton. b. Postulated geometry produced by collision and suturing of the Satpura Mobile Belt and the Bastar Craton Source: ResearchGate

10. Eastern Ghat Mobile Belt Almost running parallel to the western coast of Bay of Bengal. The Eastern Ghats ranges have discontinuous low-lying and NE–SW trending mountains of Precambrian rock. These ranges of about 1000 km length extend from Brahmani River in Orissa to around Ongole in Andhra Prades h. Maximum width is about 300km in north and tapers southwards to 30km. Fig 6. Eastern Ghat Mobile Belt. Source : https://opengeology.in/eastern-ghats-mobile-belt-egmb/

11. Impact in crustal evolution The collision and accretion of various terranes and crustal blocks along the EGMB contributed to the expansion and thickening of the Indian continental crust. Intense metamorphism and deformation results in formation of high-grade metamorphic rocks granulites and charnokites . The EGMB is known to host various mineral deposits, including iron ore, manganese, and bauxite, which have been economically important for India. The EGMB’s history is intertwined with the formation and breakup of supercontinents Columbia and Rodinia .

12. P andyan Mobile Belt (PMB) It is a part of the Southern Granulite Belt , a larger geological province characterized by high-grade metamorphic rocks. Lies to the south of the Palghat–Cauvery Shear Zone (PCSZ) and the Achankovil Shear Zone (ASZ). Experienced significant deformation during the Neoproterozoic era, resulting in the formation of a mountain range. Fig 7. Geological map of Pandyan mobile belt Source: ResearchGate

13. Impact on crustal evolution Crustal accretion and reworking : The PMB is considered a suture zone or a boundary between different continental blocks, such as the Dharwar Craton and the southern granulite terrain. During the Proterozoic orogenic events (around 600-500 million years ago), the region underwent extensive high-grade metamorphism and deformation (Pan African orogeny) Collision between the East and West Gondwana, which led to the amalgamation of the southern Indian landmass. Evidence for Collision : The widespread high-grade metamorphism and the absence of clear subduction zones as indicators of a direct collision.

14. H imalayan Mobile Belt The Himalayan Orogenic Belt is the result of the ongoing convergence between the Indian Plate and the Eurasian Plate , which began around 50 million years ago during the Cenozoic Era . The collision between these two plates has led to the creation of the Himalayan mountain range. The associated tectonic structures, including major thrust faults like the Main Central Thrust (MCT) , Main Boundary Thrust (MBT) , and the Indus- Tsangpo Suture Zone (ITSZ) , which mark the zone of continental collision. Collision led to the significant crustal reworking, with older crustal rock being thrust up.

15. Fig 8: Illustration of collision of Indian plate with Eurasian plate and formation of Himalayas. Source: https://www.ias.ac.in/public/Resources/meetings/myrmeet/26mym_talks/mkbera/img4.html

16. C onclusion Crustal accretion : Mobile belts have added significant volumes of new crust to the Indian continent. This accretion has contributed to the growth and thickening of the Indian crust over time. Deformation and metamorphism : The intense deformation and metamorphism associated with mobile belts have resulted in the formation of complex structures. Mineral resource formation : Mobile belts are often associated with the formation of valuable mineral resources, including gold, copper, and iron ore. Super continent assembly and breakup: Mobile belts have played a key role in the assembly and breakup of supercontinents, such as Gondwana, that have shaped the Earth's geological history. The Indian subcontinent has been part of several supercontinents throughout its history, and mobile belts provide evidence of these ancient tectonic events.

17. References Absar N, Sreenivas B (2015) Petrology and geochemistry of greywackes of the ~1.6 Ga Middle Aravalli Supergroup, northwest India: Evidence for active margin processes. Intern Geol Rev 57:134–158 Acharyya SK (2001) Geodynamic setting of the Central Indian Tectonic Zone in central, eastern and northeastern India. Geol Surv India Spec Publ 64:17–35 AQ5 Acharyya SK (2003a) The nature of Mesoproterozoic Central Indian Tectonic Zone with the exhumed and reworked older granulites . Gondwana Res 6:197–214 Bhadra S, Gupta S, Banerjee M (2004) Structural evolution across the Eastern Ghats Mobile Belt Bastar craton boundary, India: hot over cold thrusting in an ancient collision zone. J Struct Geol 26:233–245 Datta, A. K. (2014): Introduction to Physical Geology, Kalyani Publishers, New Delhi. Holmes, A. (1978): Principles of Physical Geology, Wiley,(3rd Ed), 730p Singh, S. (1999): Physical Geology, Prayag Pustak Bhawan, Allahabad, 555p Siddharth, K. (2015): The Earth's Dynamic Surface, Kisalaya Pub.(2nd Ed.), 600p. https://www.researchgate.net/publication/340501229 Proterozoic Mobile Belts.

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