preserved in the Strona-Ceneri Zone because areas in the upper crust were not affected nearly as much. Other research has been conducted in the Kutch District of Northwest India. It was concluded that the uplift that occurred in the area was due to intrusions of magma in the lower part of the crust. This uplift occurred because of two separate processes. One of these processes is due to magmatic underplating, while the other involves only isostasy. Research has shown that during the Oxfordian Stage a peak transgressive event occurred which was followed by the deposition of shale and sandstone. It is possible that the lower units may represent a decrease in sea level; the sea began to withdraw because of the uplift related to the magmatic underplating. Underplating Underplating is the accumulation of partial melts at the base of the crust where an ocean plate is subducting under continental crust. Underplating is the result of partial melts being produced in the mantle wedge above a subducting plate. The partial melting is induced by a lowering of the melting temperature, the solidus, by the input of water and other volatiles supplied by phase transitions in the subducting slab. When the buoyant partial melt rises upwards through the mantle, it will usually stall at the base of the crust and pond there. This is because the crust is usually less dense than the underplating magma, and this is the point at which the ascending magma reaches a level of neutral buoyancy. The evolving melt will remain there until it fractionates enough (through melting-assimilation-storage-homogenization (MASH) processes) that the remaining melt is less dense than the surrounding rock; the melt will then continue up into the crust, leaving behind the heavier mafic minerals which were crystallized during fractional crystallization. The assemblage of minerals remaining behind are typically mafic or ultramafic, and are responsible for the observed seismic anomaly which indicates underplated material. See also References Chouhan, A.K., Choudhury, P. & Pal, S.K. New evidence for a thin crust and magmatic underplating beneath the Cambay rift basin, Western India through modelling of EIGEN-6C4 gravity data. J Earth Syst Sci 129, 64 (2020). https://doi.org/10.1007/s12040-019-1335-y Plate tectonics Igneous petrology