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Pumice clasts, partially and fully coated with ferro-manganese oxide from the Central Indian Ocean Basin (CIOB) were analysed for major, trace and rare earth elements; and glass and mineral grain chemistry to assess their possible source. These pumice clasts have ∼95% glassy matrix with ∼5% of plagioclase, ortho-pyroxene, amphibole, and spinel mineral grains. Pumice is rhyolitic, with high content of silica and total alkalis and show strong light rare earth element enrichment, with La ∼100 times enriched compared to chondritic abundance and exhibits a pronounced negative Eu-anomaly. Both the partially and fully coated pumice clasts have a similar composition, but this, and their, glass and mineral (orthopyroxene) chemistry differs from all tuffs known to have erupted from the Toba Caldera Complex. The partial to complete Fe–Mn oxide coating suggests the pumice probably predates activity from the Toba caldera. Their general composition is consistent with a volcanic arc origin, and show similarities to rhyolitic eruptives from Sumatra. The distribution of partially and fully coated pumice in the CIOB overlaps with that of uncoated pumice from the voluminous YTT eruption, suggesting that other large rhyolitic calderas active in Sumatra/Indonesia. Similarities in composition to ash layers from the CIOB suggest a possible Late Miocene – Late Pleistocene age for these pumices.

The 2004 Indian Ocean tsunami left significant sand deposits along the coastal tract of southeast India (Tamil Nadu state). These deposits serve as a benchmark to understand the effects of present day tsunami on the coastline. Additionally, the geological signatures of tsunami in the coastal stratigraphy can assist in providing modern analogs for identification and interpretation of ancient tsunami. This article presents the field observations of tsunami deposits, their internal stratigraphy and foraminiferal distribution, all of which varied from north to south depending upon coastal geomorphology, near shore bathymetry and sediment sources. In a few places, the tsunami deposits have been reworked due to subsequent events that caused modification in the internal stratigraphy. The tsunami deposits of the northern Tamil Nadu coast comprise at least 50% or more reworked foraminiferal specimens, indicating that the tsunami sediments may have been derived from a paleostrandline from a water depth of at least 45 m

Benthic foraminifera have proved to be reliable proxies for understanding paleoenvironmental changes or paleoclimatic changes in the past geological history of the Earth, especially since the Cambrian when these unicellular protozoans began to evolve. Since then, foraminifers have been recorded as fossils and their abundant occurrence in the fossil record has aided in understanding the past history of the Earth. Within the Holocene, this group of microfossils has proved to be of immense utility, as their assemblages could be utilized for understanding past environmental changes, as they are so sensitive to variations in such ecological parameters as pH, depth of the water column, salinity, dissolved oxygen content, nature of substrate calcium carbonate and organic contents, which are the primary controlling factors over their species populations and diversity. The study area is a part of Kannur District, Kerala, India, about 5–7 km from the present-day shoreline. Trench samples (sub-surface) at varying depths up to 3.6 m, at Karakkeezhu and Kuduvathala, yielded a benthic foraminiferal assemblage that is characteristic of modern estuarinelbrackish water environments. This assemblage, typified by the dominance of Ammonia beccarii (Linnaeus) and its associated species, is suggestive of a shallow, probably sheltered, tidal flat environment with a possible connection to the Arabian Sea ∼5,000 to 5,500 years B.P. as revealed by 14C dates of both mollusk shells and sediment samples. The study has thrown open some intriguing questions, particularly with regard to the complete absence of arenaceous, agglutinated forms (Suborder TEXTULARIINA) and the poor representation of calcareous, imperforate taxa (Suborder MILIOLINA).

Raman and infrared intensity analysis of CHCl3 is attempted to determine the bond polarisability derivatives and bond dipole moments and their derivatives respectively, on lines expained in our earlier papers.