Microtextures on detrital quartz grains of upper Maastrichtian-Danian rocks of the Cauvery Basin, Southeastern India: implications for provenance and depositional environments

87Sr/86Sr anomalies in Late Cretaceous-Early Tertiary strata of the Cauvery basin, south India: Constraints on nature and rate of environmental changes across K-T boundary

“…Towards top of the Kallamedu Formation, paleosols are recorded implying firm establishment of continental conditions in areas that were submerged under Cretaceous sea since Santonian (Ayyasamy 2006). Based on stratigraphic variation of microtextures of quartz grains of Kallamedu Formation, Madhavaraju et al (2006) interpreted a change from coastal marine to fluvial deposition which is in conformity with these inferences. At the beginning of Danian, transgression took place that covered only the eastern part of the Kallamedu Formation (Ramkumar et al 2004b).…”

“…If the reports of Madhavaraju et al (2002Madhavaraju et al ( , 2006 who have reported prevalent rapid climatological changes in the Cauvery basin during Late Cretaceous are considered, the spikes of Sr isotope in the form of two positive anomalies might be the result of rapid and short climatic changes that accompanied siliciclastic influx events. It may also be due to the fact that, as the carbonates are deposited during sea level highstands a condition that allows less of drainage area to get exposed for weathering and transport, eventually allowing only little quantity of radiogenic Sr to reach depocenters (Denison et al 1997).…”

Quartz grain features in modern glacial and proglacial environments: A microscopic study from the Russell Glacier, southwest Greenland

“…These two schemes may also be proposed for other grain mechanical features, such as step microtextures, which are produced both in the fluvial (Udayaganesan et al 2011) and glacial environments (Strand et al 2003). This combination implies that grains may be derived from the crystalline source rocks (Madhavaraju et al 2006), or indicate sediment short transportation and rapid deposition (Gobala Krishnan et al 2015). Following this knowledge, steps are of polygenetic origin (Sweet and Soreghan 2010) and their occurrence may lead to ambiguous interpretations.…”

“…-Since the modern glacial environment is strongly linked with highly dynamic meltwater regimes including episodes of extremely intense runoff (Carrivick et al 2016 ), a number of aqueous-induced textures on the quartz grains should be considered. These are rounded outlines, low reliefs and impact v-shaped marks (Mahaney 1998;Mahaney and Kalm 2000;Madhavaraju et al 2006), which are produced during grain-on-grain impact in low-viscosity media (Sweet and Brannan 2016 ).…”

Depositional History of Coastal Plain Sediments, Southern Kerala, South West India

“…The top 9 m quartz grains are characterised by high occurrence of angular grains with the dominance of mechanical features consisting of fracture plates, meandering ridges, upturned plates, edge abrasion and conchoidal features associated with straight arcuate parallel steps and scratches (Figures 3a and 3b). These features indicate that quartz grains have undergone rapid deposition [35] which were derived from the nearby crystalline rocks [3] and transported under fluvial environment [22] of high-energy condition [1]. This reflected in the sediment texture showing angular grains of medium to fine sand deposited under violent to most violent environment (Figure 4).…”