A review of the existing knowledge on the Deccan Volcanic Province of India shows that it has a significant geographic bias towards the western parts, while the rest of the province is not as well constrained. Emerging data on its structure, geochronology and volcanology in the last decade suggests that many existing concepts and models of this large Continental Flood Basalt Province are open to revisions or replacement. The explicit relation between the Deccan volcanism and the Reunion hotspot makes it a unique laboratory for studying magmatic evolution over active hotspots, its upward trajectory through a thick continental crust and the mode and mechanics of eruption and spread of large volumes of lava on continental settings. The temporal relation of the Deccan volcanism with the terminal Cretaceous biotic upheaval has direct bearings on understanding environmental crisis that result from such eruptive events. The impact of this basaltic substrate on the anthropogenic activity of more than 100 million people living on it needs no explanation. A multifaceted and interdisciplinary study with an aim of closing the gaps in its knowledge will facilitate a well-constrained understanding of the characters and robust models of this province in the years to come.

No abstract

We review and compare morphologies from continental basaltic lavas, using examples from the Deccan Volcanic Province to compile their internal configurations, mutual associations and compare them. The mechanism of endogenous transfer of lava within an insulating (rapidly developed) crust provides an efficient mode of dispersal of the molten lava in flood basalts. The growth of the lava flow can be achieved by a single extrusion or by multiple pulses of endogenous emplacement that enable the lava to efficiently spread over large areas and thicken.We show that the morphology of a lobe manifests the response of the molten lava to several parameters (including volumetric rate of emplacement, substrate topography, viscosity, vapour loss, etc) that govern the dynamics and cooling history of basaltic lava after it starts to spread on the surface. The lateral transition from one morphology to another within lobes of a lava flow is a testimony to the interactive response of the lava dynamics and rheology to variation in the local systems in which they were emplaced. The morphologies do not evolve as rigid partitioned categories from ‘áā and pāhoehoe lava types’ but as parametric progression of interactive variations in the spreading and cooling lava.A hierarchical recognition of lobes, flows and flow fields and mapping of the morphology (and their lateral transition or continuity) combined with the stacking patterns provides the volcanological framework for a sound stratigraphic mapping of flood basalts. Such an architectural documentation of flood basalt provinces will lead to robust models of their eruptive histories.

The Lonar Crater, created by an impact of a bolide or a meteor about 570 thousand years ago in central part of the Deccan Volcanic Province, is one of the very few hypervelocity impact craters in the world carved out from the basaltic target rocks and the only crater in lava flow sequence of a Continental Flood Basalt Province. With its average diameter of 1.8 km, the crater is a simple, bowl-shaped and remarkably circular depression within a flat country dotted with sporadic conical hills. It has nearly 150 m depth and a rim that is raised nearly 20 m above the surrounding country. The evidence of it being of the impact origin is available in the form of its relatively unaltered morphology, identification of the subsurface breccias beneath the sediments in the crater, presence of shocked minerals, glasses and ejected melt breccias. Although the crater is located on the drainage divide of two moderatesized rivers, namely Purna and Penganga; there is no evidence to suggest that the impact has resulted in the disruption, truncation or reorganization of the drainage network locally or regionally.

No abstract