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The western coast of India (Kachchh) has ubiquitous preservations of Quaternary carbonate deposits popularly known as "miliolites". Field-based detail documentation of the nature and distribution of miliolites supported by sedimentology and scanning electron microscopy (SEM) microtextural studies indicates that the miliolites were primarily deposited by wind as aeolinites and are termed "primary miliolites (PM)". These were subsequently fluvially eroded and deposited and such deposits are termed "secondary miliolites (SM)". The PM are dated between 28 ka to 16 ka largely clustering around the Last Glacial Maxima (LGM). In comparison, the fluvially reworked SM occurs as valley-fill deposits and were deposited episodically during 23 ka to 10 ka before present. Climatically, the deposition of PMs suggests enhanced aridity whereas SMs represent episodic strengthening of the Indian Summer Monsoon (ISM). The bedding attitudes of the PMs indicate that they were deposited predominantly by the northeasterly winds whereas the presence of the deflation lag deposits suggests downwind migration of sands during the equilibrium condition (reduced sediment supply). The aeolian parameters (based on the grain size and wind velocities) for PMs indicate high shear velocity ($23 to 48 cm −1 ) and high transport rate (< 0.1 to 0.2 g/cm s). The short average flying distance implies that the biogenic sands were transported in multiple pulses (from coast to inland) at rates varying from $200 m/h to $1 km/h. Comparing our data with related occurrences along the biologically productive coasts in the mid-latitudinal belt indicates that the regional/global aridity during the lowered sea level was responsible for inland occurrences of aeolinites, particularly during the LGM. The strengthened northeast monsoon winds during the LGM was conducive to upwelling and production of biogenic carbonates along the coasts. The subsequent reworking of the aeolinites were mainly the results of local variability in precipitation.

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The Kachchh rift basin (KRB) in the northwestern Indian shield is one of the most seismically active intraplate regions of the world. It has witnessed four large earthquakes in the past two centuries that leads the region most vulnerable for seismic hazard. For effective seismic hazard assessment, detailed information on faults and its subsurface geometry is essential. Recently, shallow subsurface geophysical studies, particularly electrical resistivity studies have become a successful practice in imaging of fault zones and their attribute. In the present study, we carried out the time domain electromagnetic (TDEM) investigations across the Wagad highland of eastern KRB to map shallow subsurface structure and imaging fault zones in terms of resistivity. Resistivity section obtained after combining one dimensional models of 21 sites display significant details of the fault structures and geometry of shallow basin infill down to 200 m. The shallow layer of the basin infill across the South Wagad fault (SWF) and the North Wagad fault has a wedge shape made of unconsolidated deposits with thickness of ∼15-20 m. We infer that it might be due to syntectonic sedimentation due to the footwall subsidence across a branch fault of the SWF. The section indicates a ∼60-65 and 50-55 m estimates of cumulative throws for the SWF and NWF, respectively. Across the Gedi fault, the section indicates least block displacements, which might either be due to dominate strike-slip nature of faulting or more activeness of NWF compared to GF during the recent geological past. The results from the study affirm the ongoing Holocene deformation in the region signifying active nature of these faults.

The paleochannels are riverine geomorphic features, which are either buried or shifted due to tectonic, climate, and anthropogenic activities. In general, these channels serve as potential groundwater repositories, and their identification can help in developing potable groundwater sources. Here, the results of transient electromagnetic (TEM) study carried out near and around the Khari river basin of the tectonically active Kachchh intraplate region, western India are presented. The TEM investigations at 22 sites along three traverses have been carried out in the river basin that cut the present-day river channel and its presumed paleochannel. The geoelectric sections of the three profiles decipher information down to 300-350m and suggest a multilayer aquifer system. The sub-surface model infers a deeper confined aquifer at variable depths from 100-150m associated with the river as well as its paleochannel. The paleochannel aquifer is observed to be buried under 15-20m thick unconsolidated sediments that overlie a Mesozoic sandstone layer of the Bhuj Formation. The resistivity sections across the paleochannel suggest a relatively fresh aquifer layer with higher storage capacity. A vertical bedrock offset of 100-120m and the discontinuity of lithostratigraphic layers observed from the study suggest the dominant tectonic control in the formation of the paleochannel that correlated with the location of the reactivated splay of the Katrol Hill Fault.