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In this study, we conducted mineral magnetic analyses on three borehole core samples (∼40 m each) from the Kannur midland of northern Kerala, India to investigate iron oxide variations. Magnetic susceptibility (χlf) and its frequency dependency (χfd), Anhysteretic Remanence Magnetization (ARM), Isothermal Remanence Magnetization (IRM), Saturation IRM (SIRM), Hard IRM (HIRM), Soft IRM, and Munsell-Redness Rating were utilized to identify and estimate the iron oxide variations in these samples. We observed a notable shift from reductive to oxidative environments between 20 and 30 m depths among the studied cores, indicating a significant climatic or tectonic event in the region. This abrupt changeover is consistent with the lithologic change marked by a brief peat interval followed by lateritic sediments, which reflect the anoxic to oxic conditions within the closed system of the Kannur regolith basin. The basin-fill, characterized by the rapid hinterland erosion of upland laterites without the return of peat environments, suggests monsoonal intensification. The widespread occurrence of this interval within the basin may indicate a significant change in the climate. We observed an enrichment of authigenic magnetites in peat and lagoonal clays, which are succeeded by hematite and goethite-dominant estuarine to fluvial conditions inferred for monsoonal intensification during stabilized sea level and tectonic stability in the mid-Holocene. The goethite/hematite magnetic mineral ratio revealed the variation within warm-humid to warm-arid conditions, elaborating the monsoonal variability through the majority of the Mid to Late Holocene in the absence of chronology. We propose that this changeover in authigenic reductive to oxidative detrital magnetic mineralogy can serve as a stratigraphic benchmark for climate change during the Mid to Late Holocene in the Kannur basin of Kerala.

A combination of magnetic polarity and rock magnetic analysis on the well‐documented section of the Um Sohryngkew River (USR) in the south Shillong Plateau, NE India, produced a sharp reversal marking the C29r‐C29n geomagnetic polarity transition at approximately 65.688 Ma. The rock magnetic studies indicate ferrimagnetic dominant mineralogy with abundance of SSD grains, with an anomalous peak in susceptibility coinciding with Ir‐rich limonitic layer. The magnetic reversal occurs precisely 61 m above the Ir‐rich distinct in situ limonitic layer, indicating that the C29r‐C29n geomagnetic reversal post‐dates the widely accepted Ir‐anomaly based K‐Pg boundary by approximately 355 Ka. Furthermore, the rock magnetic studies indicate its frequency dependence coinciding with the Ir‐rich limonitic layer suggesting a possible dust/aerosol source, while akaganéite is reported from the interval approximately 1 m below peak susceptibility, indicating signature of Deccan volcanism. This study infers the completeness of the USR section with a high rate of sedimentation of approximately 17 cm/ka among the marine K‐Pg boundary sections in the world. [ABSTRACT FROM AUTHOR]

Indian fossil Squamata and Anura are known from the Upper Cretaceous-lower Paleocene Deccan Trap associated sediments for over last one century. However, current knowledge on their taxonomy and stratigraphic implications is poor for their scarce and fragmentary nature and lack of any stratigraphic constraints. We report newly found fossil Squamata and Anura from the new intertrappean locality Bharudpura in Malwa Plateau and describe (i) Scincomorpha (Scincoidea) lizards based on taxonomic study of dentary, maxilla and osteoderms, (ii) Anguimorpha (Anguidae) lizards based on osteoderms, (iii) Squamata indeterminate based on a vertebrae and (iv) Anura (Ranidae, Ranoidea and Anuran indeterminate) based on a ilium, a sacral vertebrae and single dentary. Currently, it is not possible to ascertain if the different fossil specimens belong to a single or more taxa. The lowermost lava pile of Mandleshwar and Kalisindh formations, associated with multiple intertrappean beds including the new Bharudpura fossil locality, have yielded40Ar/39Ar plateau ages from 66.834 Ma, the oldest Deccan Trap flow dated so far in India to 66.352 Ma. The present study records their earliest occurrence in India, from intertrappean associated with oldest Deccan Trap lava pile that erupted during magnetochron C30n of Maastrichtian in the Malwa Plateau. [ABSTRACT FROM AUTHOR]