Raymond A. Duraiswami

• Ph D
• Professor (Associate) at Savitribai Phule Pune University

Formation conditions of dimorphic minerals cavansite and pentagonite were previously based on theoretical assumptions. In doing so, the associations with other minerals, especially zeolites, that actually occur in nature, were disregarded or incorrectly taken into account. As a result, formation conditions were assumed that are not consistent with...

Variations of the short-lived decay products 182W and 142Nd that formed approximately during the first 60 and 500 million years after solar system formation are pivotal in our understanding of Hadean processes and homogenization of Earth's mantle. For example, a coupling of 142Nd and 182W anomalies for the Deccan-La Réunion plume has been previousl...

Several dykes straddle the Panvel flexure (PF) and intrude the compound pāhoehoe flows in the West Coast of India. Three geochemically distinct groups of dykes, that is, olivine normative tholeiites, quartz normative tholeiites with geochemical affinity to the Bushe, Poladpur and Ambenali formations and a nepheline normative alkali basalt are empla...

Eight nunataks in cDML, located between Schirmacher Oasis and the Gruber–Wohlthat Mountains, expose granulite facies metasedimentary rocks interlayered with pyroxene granulite. These nunataks, including Tallaksenvarden and Starheimtind, reveal ultrahigh temperature metamorphism (~630-570 Ma) with conditions surpassing 900°C at ≥8 kbar during the Cr...

Presented work focuses on the mineralogical-petrological characteristics of the interflow sediments found in the geological cross-section of lava flows exposed in the vicinities of village Khando and is the continuation of previous investigations carried out by our group within the Javakheti volcanic province.

Continental flood basalts provinces are the product of the largest known volumetric eruptions on Earth (~104 km3), with individual flow fields commonly covering well over 10 000 km2 with a mean lava thickness of over 5 m. Studies focusing on the emplacement style of such lava flows have relied extensively on morphological observations and compariso...

Cavansite is a visually stunning blue vanadosilicate mineral with limited occurrences worldwide, whereas Pentagonite is a closely related dimorph with similar physical and chemical properties, yet is extremely rare compared to Cavansite. The reasons behind Pentagonite’s exceptional rarity remain largely unknown. In this study, (a) density functiona...

Lava-flow structure and morphology provide insights into eruption styles, emplacement mechanisms, and post-emplacement alterations like weathering. However, the challenge lies in quantifying subsurface structures of buried lava flows beneath soil and vegetation cover. We present a case study of lave flow mapping employing seismic methods from the D...

The Late Jurassic-Early Cretaceous Hanle and Nidar ophiolite contains dismembered upper mantle sequences and defines the southern margin of the Yarlung (Indus)–Zangbo Suture Zone in Eastern Ladakh. The chromite mineralization occurs as massive bands in the harzburgitic peridotites, and as podiform lenses and disseminations within the dunite. Spi...

Joint fundamental research of the Mtkvari (Kura) River flood basalts and interflow horizons, which constitute a small part of the South Caucasus CFB province has started since 2016 by Georgian-Indian team. The research team project has been recently granted by the SRNSF of Georgia. It is intended to study the lava flows and associated interflow hor...

The Saurashtra peninsula in the northwestern Deccan Traps continental flood basalt province, India, contains notable concentrations of rhyolitic rocks. The Chhapariyali rhyolite dyke, part of the compositionally diverse Southeastern Saurashtra dyke swarm, intrudes basaltic lava flows. It shows vitrophyric portions, basaltic magma enclaves, gabbroic...

With a size of over 500,000 km2, the Deccan Volcanic Province (DVP) covers a large area of the Indian subcontinent. Stratigraphically continuous lava flows piled up to 3000 m record about five million years of volcanic activity. The peak activity of one million years coincides with the migration of the Indian subcontinent across the Réunion plume....

Cavansite is a visually stunning blue vanadosilicate mineral with limited occurrences worldwide, whereas Pentagonite is a closely related dimorph with similar physical and chemical properties, yet is extremely rare. The reasons behind Pentagonite's exceptional rarity remain largely unknown. In this study, we utilize density functional theory (DFT)...

Laterite is a common rock found along the Western Ghats of Peninsular India. Laterites have developed mainly over Deccan Trap basalts in Maharashtra, gneisses and metasediments in Goa and parts of Karnataka, whereas it has developed on granulite-khondalite rocks in the southern state of Kerala. The laterite has been extensively quarried and utilise...

Lonar lake is a hypervelocity impact crater formed in a basaltic terrain of Deccan Traps in the state of Maharashtra, India. The crater has an approximate radius of 915 m and an average depth of about 137 m. Here we report the results of our numerical investigations aimed to elucidate the physical characteristics of incoming asteroid. For realistic...

The 182Hf – 182W system (t1/2 = 8.9 Ma) is a useful tool to trace the presence of ancient, primordial components in terrestrial rocks. In particular, the predominance of negative µ182W isotope anomalies in modern ocean island basalts (OIBs) attracted attention [1, 2] and caused a new controversy on their origin [2, 3]. While many studies reported 1...

The southern parts of West Coast Geothermal Province, Maharashtra, India comprises mainly three localities of thermal springs occurring at Tural- Rajwadi (50-61.5 °C), Aravali (46 °C), and Unhavre (71 °C) and Rajapur (42 °C). These springs are hosted by Deccan Trap volcanic basalt cover of Cretaceous-Paleocene age (~65 Ma). We investigate the geoc...

The primary features (morphologies, structures, textures) of volcanic lava flows are determined by parameters such as composition, temperature, crystallinity, viscosity, flow velocity, strain rate and cooling rate. However, lava flows are open systems, and their primary features are strongly influenced by their emplacement environment. Among subaer...

The Sylhet Traps and the larger outcrops of the Rajmahal Traps in India constitute an important remnant of a large Continental Flood Basalt (CFB) province related to the Kerguelen hotspot. A composite log of lava flows across the southern margin of the Meghalaya plateau is presented where the Sylhet Traps are best exposed. Lavas in the lower part o...

Well-developed corona structures are observed and described in detail in the cumulate troctolites from Chainigund village, Kargil. The gabbro-troctolite unit is situated 5 km NW of Kargil city and consists of gabbros, troctolites, and anorthosites with doleritic dykes cross-cutting the unit at places. The host gabbros are fresh and display both fin...

A new and rare suite of radioactive, plutonic-hypabyssal, non-peralkaline to peralkaline, potassic to perpotassic syenites have been reported as dyke-like and/or lensoid bodies (c. 100 m × 20 m to 5 m × 2 m) within the Buxa and Daling formations (Proterozoic) and Gondwana Group of rocks (Permo-Carboniferous) within the Ranjit tectonic window (RTW)...

The lava flows of the Deccan Large Igneous Province (DLIP) cover at least one million years of continuous magmatic activity across the Cretaceous-Paleogene boundary (Schoene et al. 2021) likely representing the initial stage of the Réunion plume. Earlier studies suggested that the geochemical signatures of basaltic rocks from the DLIP main sequence...

The chemical variability of the basaltic lava flows from the 65 Ma Deccan Large Igneous Province (DLIP) has previously been explained by a single parental melt within a single magma chamber system that assimilated continental crust and lithosphere [1, 2]. The parental melt was interpreted to represent a mixture of depleted upper mantle material and...

We analyse two representative rubbly pāhoehoe lavas (F3 and F5) from drill cores at Tural-Rajwadi, southwest of Koyna, in the southern Deccan Traps. Low vesicle deformation (0.1 to 0.4) indicates that both lavas ultimately cooled under a low-stress regime. The crystal size distributions (CSDs) of most samples from F5 (especially those from within t...

We analyse two representative rubbly pāhoehoe lavas (F3 and F5) from drill cores at Tural-Rajwadi, southwest of Koyna, in the southern Deccan Traps. Low vesicle deformation (0.1 to 0.4) indicates that both lavas ultimately cooled under a low-stress regime. The crystal size distributions (CSDs) of most samples from F5 (especially those from within t...

The Spontang Ophiolite complex represents the most complete ophiolite sequence amongst the South Ladakh ophiolites and comprises mantle rocks (depleted harzburgites, dunites and minor lherzolites) as well as crustal rocks (basalt, isotropic gabbros, layered gabbros etc.). In the present study, detailed geochemistry (whole rock as well as mineral ch...

Sadara limestones in Goradonagar Formation of Pachham IslandPachham Island are dominantly intramicritic and contain bioclast, pellet, peloid, ooid; with nodular anhydrite. They exhibit intraformational chert breccia at the base, early diagenetic dolomite and predominant lime flake pebbles of intrabasinal origin in the middle, with development of al...

Crustal xenoliths, mostly of granite gneiss, occur within mafic dykes from Ranala, Rajmane-Talwade and Vadli from within the Tapi rift, northern Deccan Traps. Many xenoliths are highly brecciated, show mylonite textures and rare pseudotachylite streaks. Widespread occurrence of tridymite and cristobalite± sanidine is confirmed in xenoliths in thin...

Tural-Rajwadi group of hot springs (50−61.5 °C) is located in the southern part of the West Coast Geothermal Province (WCGP) of Maharashtra, India. The hot springs manifest in the basaltic terrain belonging to the Deccan Traps of Cretaceous-Paleocene age (∼65 Ma). To delineate the subsurface structures, a detailed geophysical exploration study has...

Continental flood basalt (CFB) provinces such as the Deccan Traps show numerous inter-flow horizons called boles, most commonly red or brown. These have been variably interpreted as altered glassy bases of basalt flows, paleosols developed on exposed flow tops, altered volcanic ash beds, or local inter-flow sediments. We believe that each of these...

The Deccan Traps continental flood basalt (CFB) province of India contains several dyke swarms, which are dominated by tholeiitic basalts and basaltic andesites. The Southeastern Saurashtra dyke swarm, containing mainly these rock types, also contains an andesite and several rhyolites. Based on petrographic, mineral chemical, and whole-rock major a...

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 e...

Jodhpur Sandstone, used extensively in several regional heritage buildings in north-western India, geologically belongs to the Ediacaran-Cambrian age Marwar Supergroup. The Marwar Supergroup has been subdivided into Jodhpur (arenaceous facies), Bilara (carbonate facies) and Nagaur (argillaceous facies) groups (in stratigraphically ascending order)....

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 paleo...

About 30 m of massive basaltic lava sheets and pillows belonging to the Deccan Traps are exposed at Borivali in the Sanjay Gandhi National Park, Mumbai (India). These lavas are conformably overlain by ~ 100 m of volcaniclastic deposits exposed in the Kanheri Caves. The pillows are plagioclase-clinopyroxene-phyric, very poorly vesicular, tholeiite b...

Geochemical variability in rocks collected from profile section, drilling core and random samples from NIASM site has been studied using x-ray fluorescence spectrometry. The sum total of all the major oxide analyses show variable degrees of weathering and range from highly weathered samples to fresh rock. Analyses were used on an anhydrous basis in...

Fifteen water abstraction structures along the two streams adjacent to the NIASM site were selected for studying the geochemistry of the groundwater and abiotic factors responsible for their distribution. The results indicated that the groundwater is alkaline with high electrical conductivity (EC). The Total Hardness is below the prescribed drinkin...

Report on the Field Training Workshop entitled “Amba Dongar Carbonatite-Alkaline Rocks and Associated Mineral Deposits” held at Amba Dongar, Kadipani, Gujarat between15th -19th March 2019

Whole rock major and trace element compositions of seven eclogites from the Tso Morari ultra-high pressure (UHP) complex, Ladakh were determined with the aim of constraining the protolith origins of the subducted crust. The eclogites have major element compositions corresponding to sub-alkaline basalts. Trace element characteristics of the samples...

The Tural-Rajawadi hot springs (Temp. 30-62 °C) are a part of the West Coast Geothermal Province of India, located at the foothills of the Western Ghats in Maharashtra state. The hot springs manifest as several small pools/puddles along lineaments within the valley that exposes five (5) surficial lava flows belonging to the Cretaceous Deccan Traps....

The Spontang ophiolite complex exposed along the Indus Tsangpo Suture Zone (ITSZ) represents a fragment of oceanic lithosphere emplaced after the closure of the Neo-Tethyan Ocean. The complex lying south of the ITSZ forms the highest tectonic thrust slice above the Mesozoic–Early Tertiary continental margin in the Ladakh-Zanskar Himalaya. The compl...

The Late Cretaceous/Palaeogene Deccan Traps, spread over half a million square kilometres in west-central parts of the Indian Peninsula, comprises predominantly basalts and subordinate felsic rocks (rhyolite, trachyte, tinguaites and spilites). The use of Deccan basalts and trachyte in the range of Indian architectonic heritage, from antiquity to c...

Once considered to be composed by monotonous stacks of basaltic lava, continental flood basalt (CFB) provinces are now known to display considerable diversity in lava flow morphology. Whereas most initial studies of flood basalt morphology and emplacement focused on younger provinces such as the Columbia River Basalt (e.g., Self et al. 1996; Thorda...

Lonar Crater located in Maharashtra (76.52°E, 19.98°N, ~563 m amsl.) , India, is a simple impact crater with a diameter of 1.8 km and the hypersaline lake formed in it lies at about 137 m below the raised rim of the crater. A previous study described the impact glasses from Lonar with respect to their geochemistry and microtextures [1]. In this wor...

The volume contains 33 abstract that were presented at the recently concluded International Seminar

The eclogites of the Tso Morari Complex, Ladakh, NW Himalayas preserve both garnets with spectacular atoll textures, as well as whole porphyroblastic garnets. Whole garnets are euhedral, idiomorphic and enclose inclusions of amphibole, phengite and zoisite within the cores, and omphacite and quartz/coesite towards the rims. Detailed electron microp...

Flow mapping and physical volcanology of 15 basaltic lavas exposed in three critical road pass sections (ghats) in the Koyna-Warna region of the western Deccan Traps is presented in this paper. Transitional lavas like rubbly pahoehoe are most common morpho-type exposed in these ghat sections. Sinking of rubbly breccia into flow interiors and format...

The tholeiitic basalt intrusives as sills and dykes from the Kutch region have been classified into high Ti and low Ti categories. The high-Ti basalts display characters comparable to the shield lavas of the Reunion Island with OIB type signature. The incompatible trace element patterns and ratios as well as the Sr-Nd composition of the high Ti-bas...

The tholeiitic basalt intrusives as sills and dykes from the Kutch region have been classified into high Ti and low Ti categories. The high-Ti basalts display characters comparable to the shield lavas of the Reunion Island with OIB type signature. The incompatible trace element patterns and ratios as well as the Sr-Nd composition of the high Ti-bas...

India is a vast country with varying agroclimate, physiography and hydrogeology. This diversity is responsible for variations in the rainfall and water resources across the country. Ever increasing demand for surface water and groundwater resources due to various developmental activities like agriculture, power and industry are depleting water reso...

Palaeoarchaean (3.38–3.35 Ga) komatiites from the Jayachamaraja Pura (J.C. Pura) and Banasandra greenstone belts of the western Dharwar craton, southern India were erupted as submarine lava flows. These high-temperature (1450–1550°C), low-viscosity lavas produced thick, massive, polygonal jointed sheet flows with sporadic flow top breccias. Thick o...

Soft sediment deformation structures such as slump folds, clastic dyke, syn-sedimentary faults and convolute bedding are present in the coarse–fine grained yellowish buff coloured sandstone, and interbedded reddish brown fine grained sandstone and yellowish–white siltstone at the Khari River section belonging to Rudramata member of Jhuran Formation...

The Phanerozoic tectonic evolution of the Kutch region (NW India) has been attributed to rifting processes. In situ U-Pb perovskite dates (all data = 124 +/- 4 Ma, MSWD = 42) obtained on three samples of a newly discovered lamproite dyke emplaced in the Kutch rift setting identify a previously unknown and relatively young (Mid-Cretaceous) magmatic...

The Kangankunde Carbonatite Complex from the Cretaceous Chilwa Alkaline Province in southern Malawi contains ankeritic and siderite carbonatite that are affected by late stage remobilisation by a carbothermal or hydrothermal fluid. The coarse pegmatitic siderite carbonatite that hosts exotic minerals like monazite, synchysite, bastnasite, strontian...

Unlike pahoehoe, documentation of true a′a lavas from a modern volcanological perspective is a relatively recent phenomenon in the Deccan Trap (e.g. Brown et al., 2011, Bull. Volcanol. 73(6): 737–752) as most lava flows previously considered to be a′a (e.g. GSI, 1998) have been shown to be transitional (e.g. Rajarao et al., 1978, Geol. Soc. India M...

Spherical aggregates of pumpellyite-yugawaralite are seen at the base (sole) of a serpentinised harzburgite sheet obducted along the Indus Suture Zone, near Hanle, Ladakh Trans-Himalaya. The pumpellyite occurs as radiating aggregates of minute, acicular, prismatic, platy crystals with sword-like terminations. Small crystal aggregates of yugawaralit...

Spherical aggregates of pumpellyite-yugawaralite are seen at the base (sole) of a serpentinised harzburgite sheet obducted along the Indus Suture Zone, near Hanle, Ladakh Trans-Himalaya. The pumpellyite occurs as radiating aggregates of minute, acicular, prismatic, platy crystals with sword-like terminations. Small crystal aggregates of yugawaralit...

The physical volcanology and morphometric analyses of pillowed lava flows from the Chitradurga basin of Chitradurga Greenstone Belt, South India have been undertaken. In the Chitradurga hills individual pillowed flows alternate with massive submarine sheet flows. The pillows from such flows are separated by chert and occur as spheroidal, elongated...

An ∼22-m-thick saucer-shaped sill occurs near Mahad and is exposed as a curvilinear, miniature ridge within the Deccan Traps. The sill has variable dips (42–55°). It has a 7.1-km long axis and 5.3 km short axis (aspect ratio of 1.4) and is larger than the MV sill of the Golden Valley sill complex, South Africa and the Panton sill, Australia. The si...

The Symbiosis International University campus at village Lavhale is situated along the eastern fringes of Western Ghats of India. It comprises important Tropical mixed deciduous forests. For this reason, the area faces great conservation concern. It supports very good plant diversity along with its faunal counterpart. The forests have a rich variet...

Thick flood basalt lava flows cool conductively inward from their tops and bases, usually developing columnar jointing. Although relatively rapid cooling in such flows due to meteoric water circulation has been previously demonstrated, mixing of the surface crust with the interior – as observed in active lava lakes – has not been shown. Here we rep...

High fluoride content in the groundwater is reported from parts of the Gad River Basin, Sindhudurg district, coastal Maharashtra, India. The fluoride content of up to 5 mg/l has been found in the groundwater in laterite, basalt and the Precambrian basement (gneiss) aquifers in the region. The presence of high fluoride in groundwater well above the...

Mantle derived xenoliths in India are known to occur in the Proterozoic ultrapotassic rocks like kimberlites from Dharwar and Bastar craton and Mesozoic alkali igneous rocks like lamrophyres, nephelinites and basanites. The xenoliths in kimberlites are represented by garnet harzburgites, lherzolites, wehrlite, olivine clinopyroxenites and kyaniteec...

Runoff has increased many fold in urban areas due to increase in paved areas, training of streams and construction of storm water drains. The recharge is therefore continuously decreasing; resulting in depleting groundwater reserves beneath large cities, especially those situated on water divides. In order to reduce surface runoff and replenish gro...

Lava flows with preserved bases and brecciated upper crusts constitute a morphological type that differs in character from typical pahoehoe and a'a: such flows have been reported from many provinces around the world. Previous studies had referred to these flows informally as ‘pahoehoe flows with rubbly tops’, ‘broken-top pahoehoe’ and ‘rubbly pahoe...

Not all the magma produced during the partial melting of the mantle always reaches the Earth's surface. Most of it cools and may freeze during its ascent through the lithosphere when the ascent rates are not sufficiently high. In continental flood basaltic provinces magmatic underplating is a quantitatively important mechanism of crustal growth and...

Crustal or mantle xenoliths are not common in evolved, tholeiitic flood basalts that cover huge areas of the Precambrian shields. Yet, the occasional occurrences provide the most direct and unequivocal evidence on basement composition. Few xenolith occurrences are known from the Deccan Traps, India, and inferences about the Deccan basement have nec...

A ∼9.75 km long, sinuous structure exposed near village Songir, east of Dhule has been previously interpreted to be a lava tube on the basis of remote sensing and field checks. Detailed field investigations, however, reveals an overlapping sequence of P-type lobes and sheets, constituting a small compound pahoehoe flow, whose sinuous form has been...

The nature and style of emplacement of Continental Flood Basalt (CFB) lava flows has been a matter of great interest as well as considerable controversy in the recent past. However, even a cursory review of published literature reveals that the Columbia River Basalt Group (CRBG) and Hawaiian volcanoes provide most of the data relevant to this topic...