The Bushe-Poladpur contact is one of the most important stratigraphic boundary separating the middle Lonavala Sub-group from upper Wai Sub-group in the Western Deccan Traps. In this paper, physical volcanology textural and petrochemical finger printing, crystal size distribution and shape preferred orientation studies (SPO) is integrated with paleomagnetic and AMS studies to correlate lavas across five localities transcending the Bushe-Poladpur boundary, south of Pune city. The flows belonging to the Bushe Formation are highly inflated, compound pahoehoe lavas, with plagioclase-olivine-phyric, coarse grained diktytaxitic textures. The flows belonging to the Poladpur Formation are transitional between pahoehoe and aa (rubbly pahoehoe lavas), with or without multi-tiered entablature showing fine-grained, olivine-phyric glassy textures. CSD studies indicate that the Bushe lavas have lower plagioclase crystals per unit area (1.11x10-4/μm2), low average effective nucleation rates (2.60x 10-12/μm3s) and high average effective growth rates (1.22x10-5μm2/s) for intact crust time than the Poladpur lavas that have higher plagioclase crystals per unit area (8.31x10-4/μm2), high average effective nucleation rates (3.46x10-11/μm3s) and lower average effective growth rates (2.24x10-6μm2/s) akin to their emplacement dynamics and cooling histories. There is a stark contrast in the magnetic susceptibilities (Bushe- 24759.8 x 10-6 SI; Poladpur-29178.02 x10-6 SI) across the Bushe-Poladpur contact. There is a general similarity between the SPO of the primary silicates (plagioclase) to the AMS derived directions. The divergence in AMS directions across the Bushe-Poladpur contact in the study area can be attributed to complex interplay of local paleotopography and slope, lava flow field dynamics, inflation and inversion of topography, style and emplacement mechanism of flow units. Generalisations and over simplifications of delineating lavas and deciphering their flow direction on a single criteria (tool) or single ghat (road section), outcrop or sample will have disastrous consequences while mapping large and complex lava flow fields. Thus, a multi-disciplinary approach needs to be the norm for characterising, correlating and mapping lavas across formations that transcend the K-Pg boundary in highly dissected ancient continental flood basalt province like the Deccan Traps.
The eastern parts of the Sistan and Baluchistan province, southeast Iran is a tectono-magmatically active zone that continues to witness numerous small and large earthquakes. The volcanism in this region is related to the subduction of the Oman plate below the Eurasian plate. The study of the spatial distribution of the epicenter and focus of the earthquakes suggests close association with the numerous faults related to collisional tectonics. Evidence of ground fractures and faulting related to Saravan earthquake of 16th April 2013 which is the largest (7.8 Mw) recorded earthquake in the region is documented. This earthquake occurred along a segment of the NW-SE trending Saravan normal fault and its reverberations were felt as far away as New Delhi and Dubai. En echelon, 2-km long, northwest-southeast trending surface fractures and faults are recorded in the field near Hampani village southwest of Gosht city. The epicenter is located in the remote hilly terrain east of Gosht. Many of the fractures are listric. The fault records a downthrow of about half a meter and some segments record brecciation of phyllite, liquefaction of sediments and emergence of saline springs are associated features. Despite the high magnitude only a few casualties and minor damage to civil structures were recorded in Iran due to the sparse population and its remoteness.
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