The present study emphasises occurrence, mineral assemblages and mineral chemistry of the Neoproterozoic Degana Peraluminous Granite (DPG) around Rewat Hill and its fertility. Based on field evidences and nature of occurrences of wolframite, the tungsten mineralization of the Rewat Hill has been classified into five types; Type-I: quartz–wolframite vein, Type-II: quartz–muscovite–wolframite–polymetallic

Abstract Tibetan Plateau (TP), a high elevation region in the Asian subcontinent, play an influential role in the Indian summer monsoon. In this numerical model study, sensitivity to the local changes in the microphysics over Tibet on the model forecast of circulation and precipitation over Indian monsoon regions is assessed. The local modification of the cloud microphysical parameters, riming, over

Abstract Biologically rich rock-pools (RPs) are prominent component of rocky intertidal habitat and this study elucidates the factors affecting the phytoplankton distribution from high-tide (HT), mid-tide (MT) and low-tide (LT) RPs (Anjuna rocky shores, Goa, India), during the summer season. Results revealed that the RP location determines the nature of phytoplankton assemblage. MT-RPs and LT-RPs supported

Abstract Based on Poisson’s relation, a generalized equation to realize forward modelling of magnetic anomalies due to arbitrarily magnetized 2D listric fault sources in any component is derived in the space domain. The non-planar fault plane of a listric fault structure is described with a generalized polynomial equation. The estimated coefficients of a prescribed polynomial are used to construct

Abstract Land and sea breezes are formed due to differential heating between land and sea surfaces and are prominent local circulation in the tropical region. We present the first observational analysis of the overview of sea-breeze characteristics based on Automatic Weather Station (AWS) data and radiosonde ascends at Bachok Marine Research Station in peninsular Malaysia. Onset criteria for sea breeze

The world's 40% of the population lives in coastal areas (<150 km from the sea), and this is set to increase in upcoming years. This urban sprawl leads to the proliferation of artificial coastal defence structures along the coasts to save the populace from coastal erosion, storms, and hurricanes. Deployment of artificial coastal defence structures has direct or indirect impacts on the local and global

Biofilm forming and heavy metal resistant marine bacterial strain Pseudomonas chengduensis PPSS-4 was isolated from the contaminated marine sediment of Paradip Port, Odisha, India. The strain showed biofilm formation up to 100 mg/L of multi-metal [Pb(II), Cr(VI), and Cd(II)] supplementation in the culture medium. Scanning electron microscopy (SEM) showed aggregation of rod-shaped cells in the extracellular

Titli was the cataclysmic storm to afflict Indian coast during 2018. Tropical cyclones may inflate nutrients on the surface layer of the ocean by entrainment and mixing, as a result, the upper oligotrophic and euphotic layers may be recharged with rich nutrients resulting in triggering phytoplankton blooms and significant increase in primary production. The biological response using the chlorophyll

Sea farm cages attract a range of wild fish species by providing shelter and food. The fish aggregation study was carried out around the open sea cages deployed at (9°20′03.95″N; 79°19′53.05″E) Olaikuda, Rameshwaram. A total of 2515 fish representing 51 species from 26 families and 9 orders were recorded by Underwater Visual Census (UVC) method from both sea-cage farm and control site. The genus Siganus

Abstract This study provides an evaluation of the past, present, and future spatiotemporal variability of droughts in the Bundelkhand region of central India. The assessment has been made by analyzing the existing (1951–2018) drought dynamics with gridded observational and reanalysis datasets. The future projection is presented using a multi-model ensemble from 21 simulations of regional climate model

Abstract Agriculture in hill and mountain ecosystems is predominantly rainfed with common occurrence of moisture stress. It is a natural disaster which evolves in time and its impacts last for a long time. In the present investigation, long-term monthly precipitation data for 40 years (1980–2019) were used for characterizing agricultural drought in Almora and Nainital districts of Uttarakhand in India

The Sonapahar sillimanite-corundum deposit of Meghalaya, Northeast India occurs within high-grade metapelites and exhibits an unusual association of sillimanite-quartz, corundum-quartz, sapphirine-phlogopite-corundum-sillimanite rock. Pockets of sillimanite and corundum occur within the host quartz sillimanite schist with contrasting chemical signature, where the SiO2/Al2O3 ratio is 2.5–3 for the host

The eastern margin of the Chitradurga Schist Belt is widely believed as the dividing line of Dharwar Craton (DC) into Western Dharwar Craton (WDC) and Eastern Dharwar Craton (EDC). This study aims at re-defining the division of DC based on pronounced gravity high encompassing Chitradurga Schist Belt of WDC and Closepet granite to Ramgiri–Penackacherla Schist Belt of EDC. The newly acquired high-resolution

Abstract Granitoids from Pindwara–Abu Road Belt (PARB) are studied to characterize their tectonostratigraphic status in relation to the associated metasediments. The PARB lies along the southern swathes of the Mesoproterozoic Delhi Supergroup (DSG) in the Aravalli Delhi Mobile Belt (ADMB) of the northwestern Indian Shield. The outcrop scale granitoids of the study area are categorized into massive

Once an important accessory for petrographic microscope and a valuable tool in mineralogical and petrofabric work, the Universal Stage (U-stage) has been dubbed obsolete with the advent of electron microprobe and XRD, and subsequent phasing out of the production of the optical equipment. Modern-day fabric analysis also relies more on far more expensive texture goniometers, neutron activation analysis

Many previous studies have documented the changes in rainfall patterns along the Western coast of India. The Western Ghats of India comprising of coastal regions of Maharashtra, Karnataka, and Kerala regions are facing the worst floods and droughts in recent years. Changes in low-level horizontal wind circulation due to the change in sea surface temperature over the northern Arabian Sea have been reported

The present study summarizes the existing chronometric data of fossil dunes preserved in the southern Thar Desert margin (STM). The objective is to understand the episodes of dune accretion and causes of their spatial and temporal variability along the precipitation gradient. Based on the published ages, the study identifies three major phases of dune accretion. The oldest phase-I is dated between

The aim of this study is to assess and forecast spatial pattern changes of dust and wind speed in Hamun-e Helmand basin, Sistan region. This region has the most dust events and the strongest winds, including 120-day winds. Wind speed and dust data of seven synoptic stations were therefore extracted from the Iran Meteorological Organization during 1990–2018. Wind and dust speed were predicted for 2020–2030

Abstract Tidal hydrodynamics of the Gulf of Khambhat (GoK) were studied with the observed and simulated datasets. The flushing time of the Gulf was estimated using the 2D-model calibrated and validated with the tide and current speed observations. Model simulations were carried out with the influence of tide, wind, and tide and wind combinedly. Wind-driven flushing was found to be the least with the

Abstract Carbon isotopes of stalagmites are influenced by various factors operating in a cave, like evaporation, vegetation, drip rate and changes in partial pressure of carbon-di-oxide (pCO2) inside and around a cave system. Consequently, interpretation of δ13C record becomes a bit complicated. However, the vegetation changes at a given cave location are generally considered as the dominating factor

The present study describes the active role of met-ocean parameters on the heavy flooding that occurred during July 2018 in the Kuttanad region, Kerala. The model-derived data as well as observations showed a high anomaly of wave height in July 2018 off Kerala was not correlated with local wind anomaly and indicated possible connection of wave anomalies to swell waves. The high period and high amplitude

Uranium mineralization occurs adjacent to the unconformity between Paleoproterozoic granite and Meso- to Neoproterozoic cover sediments in Chitrial prospect of Cuddapah Basin in Indian shield. Hydrothermal activity in the granite is evident by the presence of hydrothermal veins and associated wallrock alteration in the unconformity zone (0–5 m below unconformity), shallow zone (5–100 m), and deep zone

Abstract Coupling of the geological processes in the arc-magmatic and back-arc provinces of accretionary orogens in Neoarchean plate tectonic setting is a subject of current research all over the world. The Dharwar Craton of southern India is an example of such an accretionary orogen, with an arc-magmatic province in the east and a back-arc province in the west, referred as the Eastern Dharwar Craton

Abstract Seawater incursion and freshwater discharges into the tropical Mandovi Zuari (MZ) estuary is investigated here using stable oxygen isotope data on monthly water samples from locations spatially separated within the estuary. Surface water samples were analysed for δ18O and salinity relationship, $$\delta^{18} O = 0.0843 \times S - 2.1,$$ where freshwater end member is designated as −2.1‰; similar

Abstract The nature and distribution of heavy minerals along beach placers have been studied along the coastal part of Podampata, Eastern Coast of Odisha, India. The primary objective of this study was to assess the heavy mineral placers along the NE–SW direction, the nature of the high background radiation area, and the geomorphic agents controlling the beach sediment distribution. In-situ total radiation

Abstract The human–environment interactions are entwined across different spatio-temporal scales. The prime focus of this study is to investigate the wide range of changes happening in seasonal maximum and minimum temperatures (Tmax and Tmin) during 1950–2012 over the island country Sri Lanka in the deep tropics and to analyse associated important drivers explaining these changes. Fingerprint-based

Abstract Absorption spectra of coloured dissolved organic matter (CDOM) and their derived parameters such as, absorption coefficient and spectral slopes are useful to study the molecular weight distribution of DOM. Here CDOM absorption characteristics were assessed in two distributaries [Gautami (GGE) and Vasishta (VGE)] of the Godavari estuary to examine the differences in molecular weight characterization

Abstract A major portion of the coastline of Kerala is under erosion, primarily due to the action of wind-generated waves. Accurate assessment of the nearshore wave climate is essential for detailed apprehension of the sediment processes that lead to coastal erosion. Numerical wave transformation models set up incorporating high-resolution nearshore bathymetry and nearshore wind data, prove to be sufficient

Abstract Magnetotelluric (MT) data has been collected along 32 stations along E–W profile in northern part and eight LMT (long period MT) stations in north-central part of Saurashtra region. Dimensionality analysis is carried out prior to MT modelling for obtaining the subsurface dimension as well as the direction of the underlying substructures. To estimate the subsurface dimensionality from MT data

Fluoride (F–) pollution in groundwater of the Older Alluvial Plain (OAP) of Delhi has been reported as a major problem. About 34% of the groundwater samples collected for this study had F– level beyond the permissible limit; with F– concentration in the range of 0.14–3.15 mg/L (average 1.20 mg/L). In this context, this article for the first time attempts on the genesis of major ions chemistry and F–

The present study examines the tropical cyclones (TCs) activity over the Bay of Bengal (BoB) during post-monsoon season (October–December) for the period 1972–2015 (44 years period). The study has explored the active and inactive TC years on the basis of mean ±1 standard deviation, respectively. A total of nine active (when TCs frequency is ≥4 in a year) and 18 inactive (when TCs frequency is ≤1 in

We report the chemical composition of 176 glass spherules obtained from Antarctica blue ice and deep-sea sediments from the Central Indian Ocean Basin. This study compares the chemistry of glass spherules collected from various reservoirs, thereby allowing us to look into possible bias and efficiency of different collection techniques. Glass spherules have experienced extreme heating among the S-type

AbstractSection Abstract Molar-tooth structures (MTS) are enigmatic, micro-crystalline calcite-filled fissures, confined in Proterozoic carbonates. Here we present petrography, carbon isotope, total organic carbon (TOC) and morphological attributes in the context of interpreted palaeoenvironment to understand its development in the Mesoproterozoic carbonates of Lesser Himalaya. Lack of any detrital

Abstract The need for adequate planning and management of marine areas has been progressively realised due to the prevalent and ever-increasing ‘use-conflicts’ in time and space, amongst different maritime sectors. Marine Spatial Planning (MSP) is an effective approach to ensure marine conservation and prevent over-exploitation of marine resources by sustainably utilizing its economic potential. Literature

Continuous measurements of absorbing carbonaceous aerosol termed as black carbon (BC) have been carried out during April 2017 to March 2018 over Solapur, a semi-arid, rain shadow location in Peninsular India using a multi-wavelength Aethalometer (AE-33). Statistically significant higher values of BC were observed during the dry period (December–May, mean BC 4.3±1.2 µg m–3) as compared to the wet period

Abstract Pan-African (ca. 620–390 Ma) granites (sensu lato) are exposed as small circular to elliptical intrusive bodies (stocks or plutons), viz., Karamadai (Kar), Sirumugai (Sir), Punjaipuliyampatti (Pun), Tiruchengodu (Tir), Sankari (San), and Idappadi (Ida) along the E–W trending Cauvery shear zone (CSZ) of Southern Granulite Terrain (SGT), central Tamil Nadu. Mineralogically all these plutons

Abstract The exposed granite gneissic complex to the west of Cuddapah basin in Eastern Dharwar Craton (EDC) is studied to understand the magnetic character of various plutons in this region with more emphasis on a part of Closepet Granite (CG). The NW–SE trending plutons in this region show gradual decrease in magnetic intensities from southwest to northeast; CG in the southwest corner of the study

Abstract The rise of the Himalayas governed the Indian Summer Monsoon in Karewa basin during Plio-Pleistocene. A palynological study is presented to delineate the climate-vegetation relationship using an 8.5-m thick fluvio-lacustrine sequence of the Hirpur Formation (2.4–2.1 Ma). Our results suggest that the sediment sequence is mainly comprised of two units, namely, Unit 1 and Unit 2. Unit 1 shows

Abstract Southern Lower Indus basin is an oil and gas prone basin, which is important for producing hydrocarbon in Pakistan. Due to limited Rock-Eval pyrolysis data availability in the prospective shale gas basin, the organic facies geochemical characteristics study is a challenging task for researchers. The primary objective of this study is an evaluation of the Lower Goru Formation organic facies

Here, we report for the first time, the genus Lamellibrachia tubeworm and associated chemosynthetic ecosystem from a cold-seep site in the Indian Ocean. The discovery of cold-seep was made off the Cauvery–Mannar Basin onboard ORV Sindhu Sadhana (SSD-070; 13th to 22nd February 2020). The chemosymbiont bearing polychaete worm is also associated with squat lobsters (Munidposis sp.) and Gastropoda belonging

Wind observations are critical for the better atmospheric analysis for Numerical Weather Prediction (NWP), particularly over the tropics. High-resolution direct wind observations are essential for defining smaller scales and deeper atmospheric structures. Recently launched Aeolus satellite delivers wind profiles that mostly satisfy these requirements, suitable for NWP assimilation. The main product

This study examines textural characteristics, carbonate, organic carbon and chemical composition of sediment samples recovered in the nearshore region (~3–19 m water depth) at the Grijalva River mouth, southern Gulf of Mexico. The aim of this study is to assess the heavy metal contamination and provenance variations in sediments between the dry and northers (rainy) seasons. The proportion of sand,

The Early Permian marine strata exposed at the Siang and Subansiri districts, Arunachal Pradesh are known for brachiopod and molluscan fossils. A stratigraphic review and palaeoenvironmental, palaeoecological, and palaeobiogeographic interpretation of these Early Permian fossils have been dealt here on the basis of additional fossil and rock materials. Our study confirms the following: (1) the brachiopod-dominated

Abstract A significant occurrence of olivine and serpentine (antigorite, lizardite) are reported for the first time in the Dihing sedimentary unit of upper Assam. Petrography of the Dihing Formation documents olivine, serpentine (antigorite, lizardite), pyroxene and major framework grains (quartz, feldspar and variety of lithic fragments). Based on modal composition, the Dihing unit samples are classified

Abstract The tropical Indian Ocean is a net sink for the carbon dioxide (CO2) in the atmosphere and phytoplankton production plays a crucial role in CO2 fixation and determines the direction of CO2 flux at the sea-to-air interface. In order to assess the influence of phytoplankton composition and primary production on pCO2 levels in the Indian Ocean, sampling was conducted at 25 stations during the

Geological and geochemical characteristics of the litho units exposed in and around Kalalikhera area of Pur-Banera belt have confirmed the presence of felsic volcanic rock unit named Kalalikhera felsic volcanic, with characteristic features such as (i) abundance of lapilli composed of polygonal quartz and feldspar and (ii) presence of relict bipyramidal quartz. These volcanics are associated with thin

Abstract Gas hydrates from the continental margin settings are mostly confined to continental slopes. The free gas occurring below the gas hydrate laden sediments play a crucial role in the submarine slope failures and can potentially trigger the submarine landslides. The present study is carried out to investigate such a scenario in the shale dominated Krishna–Godavari (KG) basin having proven gas

Prediction of heavy/extreme rains is still a challenge, even for the most advanced state-of-the-art high-resolution Numerical Weather Prediction (NWP) modelling systems. Hydrological models use the rainfall forecasts from the NWP models as input. This study evaluates the performance of the UK Met Office Unified Model (UM) in predicting the rainfall exceeding 80th and 90th percentiles. Such high rainfall

Snow/ice cover is an integral part of the Earth’s climate system. Earth’s snow/ice cover helps regulate the energy exchange between the Earth’s surface and the atmosphere, directly regulating the surface (and near-surface) temperatures. This study utilizes measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43C3 dataset to derive the albedo and snow cover variation over the

Groundwater recharge is a hydrological process where water flows from sub-surface layers to the water table of the aquifer and is the backbone of the hydrogeological system. The present study is carried out in a granitic hard rock aquifer region within and surroundings of the CSIR-NGRI campus, Hyderabad. The aim of this study to identify the potential groundwater recharge zone(s) using GIS based multi-criteria

The Delhi Seismic Zone (DSZ) is a seismically highly active intraplate region that keeps experiencing recurrent seismicity of minor to moderate nature. The seismic activity in the DSZ in recent times has evoked concerns about the vulnerability of the region due to potential earthquakes. Although the spatial distribution of recorded earthquakes gives a fairly good idea about the zone of the seismicity

Abstract We describe the variability of the West India Coastal Current (WICC) during 2009–2017 using data from acoustic Doppler current profilers (ADCPs) attached to moorings deployed on the outer shelf at a water-column depth of 100–200 m at three locations: off Kollam (9°N), Bhatkal (13.9°N), and Goa (15°N). Our study shows that the characteristics of the WICC on the outer shelf are similar to those

A short-lived flashflood in Rishi and Dhauli Ganga rivers on 7th February 2021, Uttarakhand Himalaya, killed 65 people with 141 reported missing (official estimate) and devastated two hydropower projects. Geomorphological observations supported by meteorological data suggest that the flood was triggered by a combination of avalanche and debris flow. The Dhauli Ganga valley has preserved ponded sedimentary

We report microtektites recovered from a large area of the deep seafloor (Central Indian Ocean) that appear to have undergone aerodynamic distortion during re-entry into the atmosphere. Considering the geographic locations, stratigraphic position and chemical compositions these glassy forms belong to the Australasian tektite strewn field. The microtektites are elongated to lengths of cms, sometimes

Abstract Deep-sea moorings in the equatorial Indian Ocean were first deployed by India in the year 2000, and currents were measured at three locations (\(77^\circ \hbox {E}\), \(83^\circ \hbox {E}\), and \(93^\circ \hbox {E}\)) on the equator. In this paper, we present two decades of current observations from these moorings and discuss how the moorings have evolved with time. The observations show

Abstract Malani Igneous Suite represents the largest felsic volcanic province in India. Despite a number of studies, the origin and the temporal extent of the Malani magmatism remain elusive. Adjacent to the Malani Igneous Suite, there exists a calcareous felsic tuff deposit at Chhoti Khatu within the younger Marwar Supergroup. It is stratigraphically separated from the Malani Igneous Suite by the

Abstract An automatic 3D spatial domain inversion technique is developed to estimate basement depths of sedimentary basins from observed gravity anomalies using a prescribed exponential mass density contrast. A collage of vertical polygonal cross-sections, each one with unit thickness, in which the density contrast differs exponentially with depth describes the model space. The proposed technique estimates

Abstract Rip currents are known as one of the most dangerous hazards on sandy beaches worldwide. Indian beaches are least explored to study the variability of rip currents in space and time. The present study is the first attempt made to understand its dynamics by utilizing indigenously developed GNSS (Global Navigation Satellite System) drifters and Rhodamine-B dye experiments. The Rama Krishna (RK)

Abstract Thunderstorms, associated with lightning and heavy rain, are a weather hazard causing human deaths, urban floods and damage to crops. Current work attempted to study the thunderstorms over Andhra Pradesh, coastal state in southeast India, using multiple satellite datasets, gridded rainfall, Doppler Radar Images and Advanced Research Weather Research and Forecasting (ARW) model simulations