Deccan Traps, Indiai

Regional Level Types
Deccan Traps	Large Igneous Province
India	Country

The Deccan Volcanic Province (DVP) is one of the largest continental flood basalt provinces(CFBs), which are represented by voluminous basalt flows such as the Columbia River Basalt Group, the Paraná traps, and the North Atlantic Igneous Province. Most of the lavas erupted between 67.5 and 60.5 Ma and were fed by three main dyke swarms, namely (1) those trending N–S to NNW–SSE between the Arabian Sea and the Western Ghats; (2) those occurring along the Narmada-Satpura-Tapi region with an ENE–WSW strike; and (3) those located in a zone in the Western Ghats northeast of Mumbai, which have no preferred orientation. Three stages of volcanic eruptions can be distinguished at around 67, 65 and 64 to 60 Ma, interrupted by two periods of quiescence lasting 2 MY and 500,000 years, respectively. Recent calculations by Sprain et al. in the Western Ghats indicate that the main effusions took place with over 90% of the total volume between 65.4 and 66.4 Ma. It is believed that the Deccan volcanism is linked to widespread animal extinction at the K–Pg boundary (formerly K–T boundary) due to degassing of large amounts of CO₂ and SO₂.
The DVP originally covered an area between 2,600,000 km² and 750,000 km². Nowadays, the DVP basalts are distributed over an area of 500,000 km² and can be subdivided into four divisions: Main Deccan Province, Malwa Plateau, Mandla Lobe, and Kutch. The paleo-thickness of the DVP is unknown, but it is assumed to have reached a maximum of around 3500 m in the Nashik area. Large masses are eroded and the current maximum thickness near Nashik is about 2200 m. The stratigraphy of the DVP is divided into three major subgroups: Kalsubai (2000 m thick), Lonavala (525 m thick), and Wai (1100 m thick), ordered from older to younger, as well as twelve formations. Each formation is characterized by accumulations of large composite sub-horizontal tholeiitic lava flows with varying thicknesses and chemical or mineralogical compositions. Based on these characteristics, simple and compound lava flows are generally distinguished. Compound flows are abundant in the northwestern and central parts of the MDP within the estimated distribution of the Kalsubai subgroup. The time between the eruptions of the two consecutive flows can vary widely, from hours, months, or years to thousands of years. Since age dating of such short time periods is not possible, the degree of alteration of the surface zone plays an important indicator role. Surface weathering with a dependence on time and climatic conditions has resulted in more or less marked red or green alteration zones. These horizons are not very pronounced in the investigated area of the MDP and indicate short interruptions of up to several years between the lava flows. Fossils or microfossils were not detected in the ancient surface zones of the MDP basalts. The MDP consists of basalts without intercalated or overlaying sediment layers. [Götze, J. et al. (2020)]