Sedimentary Basins of India

Primarily found in the Salton Sea and the dead sea, pull-art basins are formed after frequent bends in the adjacent faults to create an extension or compression stress, resulting in regional strike-slip basins. A regional strike-slip fault is a central displacement zone connecting the tips of step-over faults bounding basin sidewall faults. 

• Remnant Basins

Remnant ocean basins are shrinking ocean basins created by a collision between continental margins or an arc trench system, with accumulated deep-water sediments mainly collected from the associated zones ultimately subducted within belts. 

When a piece of lithosphere collision eventually comes to pass, a certain salient of continental crust encounters the subduction zone before re-entrants. Further subduction and suturing create isolated basins that are still floored by residual oceanic crust, which receives abundant sediment from the strongly uplifted crust.

• Trench Slope Basins

Areas of deeper water are referred to as basins, trenches, or troughs. Basins are large areas of relatively uniform depth, like plains on land. At the same time, trenches have much steeper sides, more like a steep slope of a mountain. 

Deep-marine salts and muds are sedimented directly into the basins or slumped into the bays from higher to the bottom slope of the trench; also, rough components or sediments are supplied from farther upslope by turbidity currents.

• Intracratonic Basins

Intracratonic basins are basins that have no apparent connection with the tectonic plates. It is formed in a rounded, equidimensional shape which takes hundreds of years to mould itself. The formation is reflected slowly after a heating event occurs in the continental lithosphere. 

Subsidence is very slow because no signs of depression could be seen on the upper surface. Sediments like carbonates, shales, or sandstone could be formed in the adjacent layers, much broader in size.

Major Sedimentary Basins of India

India covers an estimated 3.36 million sq km of sedimentary area. Comprising 26 sedimentary basins, out of which 1.63 million sq km are present on the land, sedimentary basins make their way to the shallow offshore up to 400m isobaths with an area of 0.41 million sq km. Besides that, the deep-water beyond 400m isobath has a sedimentary area of 1.32 million sq km. Covering this vast area, major sedimentary basins that cover most of these regions in India are as follows:

• Krishna – Godavari Basin

Covering an area of 2.3 lakhs in Andhra Pradesh and the adjoining regions of the Bay of Bengal, the Krishna-Godavari basin covers an area of 15000 sq. km on the continental part and the offshore aspects with 25000 km with an isobath of up to 1000 m.

Krishna Godavari Basin is a continental passive margin basin. It was formed following a rift along the eastern continental margin of the Indian Craton in the early Mesozoic. 

• Pranhita – Godavari Basin

The Pranhita-Godavari basin extends for about 400 km with a width of approx. 100 km. The aggregate thickness of the basin deposits is estimated at about 6000 m.

• Saurashtra Basin

This Basin lies between the north of Mumbai offshore and south of the Kutch basin. Tectonic movements in the Tertiary were milder and cyclic, represented in the column as extensive inconsistency.

• Kerala – Konkan Basin

This offshore basin forms the southern region of the western continental margin of India and covers an area of around 580,000 Sq.Km. It extends from Goa in the north to Cape Comorin in the south.

• Himalayan Foreland Basin

The Himalayan foothills basin is a northwest – southwest aligned Basin located in the foothills region of Himalaya. It covers 30,300 sq km and has areas that sequence the order of 10km thickness in the sediments section. The sediments section comprises hydrocarbons, i.e., petroleum, coals, and limestones.

• Bengal Basin

Bengal basins occupy an area of 89,000 sq. km in total, about which 57,000 km on land and 32,000 km offshore up to 200 m bathymetries. The approximated thickness of the deposited sediments is 20 km in the proximal deposition section. Furthermore, they capture sediments like sandstone, coal, and hydrocarbon-associated materials as their primary ingredient.

Conclusion

The concept of sedimentary basins in India is very crucial to learn. It helps learn the geological processes in nature to make these sediments come alive. Major sedimentary basins in India are Krishna – Godavari Basin, Pranhita – Godavari Basin, Saurashtra Basin, Himalayan Foreland Basin, Kerala – Konkan Basin and Bengal Basin. Sedimentary basins are important because the sedimentary rocks’ primary ingredients are petroleum, natural gas, and coal. This largely contributes to the rapid economic expansion of India.