Anil D. Shukla

Physical Research Laboratory Ahmedabad · Geosciences Division

Chemical analysis of nine Deccan flow basalts at Anjar, Kutch, western India, indicates that all, except the uppermost flow F-9, are alkaline. In their major and trace element composition, the alkali basalts resemble Ocean island basalts (OIB). Similarities of many diagnostic trace element ratios (e.g. Sm/Nd, Ba/Nb,Y/Nb and Zr/Nb) are similar to th...

Abstract—Two stones that fell near Piplia Kalan on 1996 June 20 are identified as Ca-rich achondrites belonging to the eucrite group. The conditions of their fall are described. The petrographic description, texture and chemical composition, the elemental ratios, particularly K/La and Yb/Sc, and relatively flat rare-earth-element (REE) patterns...

The Vindhyan Basin of western India is a part of the largest Proterozoic sedimentary basin of the Indian subcontinent. Deposited in a largely shallow marine environment, the sedimentary sequence of the basin, known as the Vindhyan Supergroup, is believed to hold clues to our understanding of the evolution of life and climate during the Proterozoic....

Being a part of the large-scale Indus-Tsangpo suture zone ophiolites of the Alpine-Himalayan orogenic system, the Neo-Tethyan ophiolites of eastern Arunachal Himalaya, northeast India, are important in understanding the formation and evolution of the Neo-Tethyan lithosphere. This study focuses on the hornblendite dykes occurring within serpentinize...

This study addresses the nature and causes of post-Last Glacial Maxima (LGM) sedimentation in the Western Great Rann of Kachchh, Gujarat, India. Specifically, we report geochemical and isotopic data ( 87Sr/86Sr and 143Nd/144Nd) for a 46.5 m sediment core from the Nara River bed. These data indicate that up to the beginning of the Holocene, sediment...

This study reports for the first time Fe-Ti-V oxide and Cu-sulphide mineralization in Paleoproterozoic Mangikhuta basalt Formation, central Indian craton. Electron microprobe and laser ablation analyses of Fe-oxides reveal high FeO (45 – 69 wt %), TiO2 (19 – 53 wt %), V (1860 - 4990 ppm), Zr (394 – 3130 ppm), Nb (55-285 ppm) and Zn (324 – 668 ppm)....

The geomorphological disposition of (para/peri) glacial landforms, elemental geochemistry, and optical chronology of the relict lake sediment in the Southern Zanskar ranges, northwest Himalaya are used to understand the relationship between glacial dynamics and the lake sedimentation during the mid-Holocene climate variability. Following the Last G...

The Holocene sea-level and associated shoreline regression of beach ridges in the central west coast of India have been reconstructed based on internal sedimentary architecture and luminescence chronology. For this purpose, various techniques namely ground penetrating radar (GPR), optically-stimulated luminescence (OSL) dating, and interferometry s...

The present study aims at understanding the chronology and pattern of extreme flood events in the upper Ganga catchment. Towards this, we explored relict alluvial sequences, particularly the sand bodies overlying the fluvial gravels and underlain by the source proximal alluvial fans and debris flows, supported by geochemistry, and optical chronolog...

Petrographic, whole‐rock geochemical and geochronological analysis of polymictic conglomerate, associated siltstone and greywacke in the Neoarchean Gadag Greenstone Belt in the Western Dharwar Craton, India, provides new insights into sedimentary provenance and tectonic setting. The polymictic conglomerate contains granitic, gneissic, felsic and ma...

The article is on new meteorite fall in Gujarat, India in 2022. Classified as aubrite

Hot spring localities on continents may represent the most probable locales for the formation of early life constituents on Earth. Apart from liquid water and carbohydrates, these components also include elements like boron that are crucial for stabilization of the complex organic molecules that constitute life. Many of these life sustaining ingred...

The present study attempts to understand the geomorphic response in the upper Ganga catchment to the mid-late Holocene (neoglacial) climate variability. The study infers five major phases of millennial-scale climate variability with centennial-scale inversions using geochemical and magnetic proxies from relict Lesser Himalayan Lake sediments. Phase...

The Holocene arid events and related societal responses are important scientific inquiries due to concerns about their reoccurrences in the future. In the Indian subcontinent, significant number of studies have focussed on understanding the Holocene aridification events at 8.2 and 4.2 ka. Despite these studies, high resolution palaeoclimatic record...

In the northwestern Himalaya (Ladakh and Karakoram), the spatial and temporal changes in the late Quaternary glaciation were modulated by a combination of two contrasting moisture sources (viz., the Indian Summer Monsoon and the mid-latitude westerlies). The inferences about their relative contribution to glacier expansion are based on the ages obt...

The Mukundpura carbonaceous chondrite represents the negligible thermally affected with modest aqueous altered chondrite, providing a new unique opportunity to investigate the composition of the early solar system materials. We investigated cosmogenic records using radioactive and stable isotopes in Mukundpura. The cosmic ray exposure (CRE) age of...

The Kachchh Basin is a peri-cratonic rift basin in western India, exposing a vast range of diverse geologic features representing the past 200 million years spanning from the Jurassic Period to the recent. The Basin represents highly rugged terrain in the form of the hilly ranges and pediment surfaces, while the flat terrain in the north is express...

Alaknanda River valley in the NW Himalaya (India) has been subjected to frequent landslides of different types and sizes owing to its geographical position and topography that receive extreme rainfall from Indian Summer Monsoon and Western Disturbance. Such landslides, mainly debris flow, pose a growing risk to the rapidly growing human population...

Ephemeral fluvial systems in the dryland region of Kachchh are susceptible to climatic fluctuations. An increase in Indian Summer Monsoon Intensity (ISM) is responsible for the aggradation of sediments as valley-fill deposits in the river basins. In the present study sedimentological, chronometric, and geochemical analysis on the fluvial terrace se...

The Zagros phosphogenic horizon, hosted by the Eocene-Oligocene Pabdeh Formation, is located in the NW-SE-trending Zagros Fold-Thrust Belt (ZFTB), Iran. These phosphorites, which formed along the Tethyan Realm, are the most important and highest-grade phosphatic resources of Iran. This paper discusses the evolution and depositional paleoenvironment...

The Indo‐Myanmar Range is thought to represent a relict eastward‐dipping subduction zone that runs from the eastern edge of the Himalayan Range. In the Indo‐Myanmar Ophiolite (IMO) Belt rodingite is present as discontinuous lenses, dikes, and small‐ to medium‐sized blocks in the serpentinized zones of ultramafic rocks. Petrological and geochronolog...

The present study focuses on the mechanism, climate, and sea-level implications of the coastal dune building activity in the eastern coast of Kori Creek (Gulf of Kachchh). Around 10 m thick dune is investigated using sedimentology, geochemistry, and optical chronology. This study suggests that the dune sediment that overlies the Tertiary Oyster Bed...

Himalayan glaciers‒ the store house of fresh water outside the polar region contributes ~45% of the total river flow by glacial melt in the Indus, Ganga and Brahmaputra watersheds which supports the livelihood of ~500 million people . The sustainability of these rivers is being questioned because of the growing evidences of accelerated glacier retr...

The loess-paleosol proxy records from mid-latitude Asia have been instrumental in the reconstruction of regional paleoclimate evolution and its relationship with global climatic changes. The present study explores the discrete occurrence of a loess and paleosol sequence (LPS) in the Southern Zanskar Range (SZR), NW Himalaya. Stratigraphic variation...

The Tamil Nadu coastline, India, has extensive dunes which can be used for inferring quaternary palaeocli-mates. In the present study, we aim to determine the chronology of the dunes in the Vaigai prodelta region along the southeastern coastline of the country. Optically stimulated luminescence ages for the elevated beach ridge samples SANK-5, SANK...

The Neoarchean potassic granite from the Hosadurga region adjacent to the Chitradurga greenstone belt (CGB), part of the western Dharwar Craton (WDC), is studied for its petrogenesis. The combined field, petrographic, whole‐rock elemental, and Nd–Sr isotope data of granite and associated Tonalite–Trondhjemite–Granodiorite (TTG) gneiss from this reg...

The discovery of iron-bearing concretions is one of the exciting discoveries in recent past on Mars. We report here an analog terrestrial site hosting hematite-bearing concretion belonging to Jhuran sandstone, Kutch, India. Based on petrography, mineralogy, geochemistry and spectral studies (Visible Near Infrared: VNIR and Mössbauer), we found a ve...

Here, radiogenic strontium isotopes, and stable carbon and oxygen isotopes analyses of the Paleocene-Eocene limestones of the Jaisalmer basin, Western India are carried out to find out the evidences of Paleocene-Eocene thermal maximum and Early Eocene Climatic Optimum. The occurrence of Numulites burdigalensis suggests the succession to be a Paleoc...

Sandstones of the Sanu Formation from Jaisalmer basin, western India were studied for major, trace and rare earth element (REE) geochemistry to deduce their paleo-weathering, tectonic setting, source rock characteristics and provenance. Geochemical results suggest that these sandstones can be classified into sub-arkose, which is supported by petrog...

A single piece of meteorite (~15 kg) fell on Mahadeva village of Madhubani district in the state of Bihar in India on July 22, 2019. Based on petrochemical studies, Mahadeva is classified as H-chondrite. Homogeneous olivine (Fa:19.3 mol%) (percent mean deviation <4%) and low-Ca pyroxene (Fs:17.6 mol%) composition further suggest that Mahadeva is hi...

We report the textures, mineralogy and mineral chemistry of the Mukundpura matrix component, a clast-bearing, brecciated, new CM2 carbonaceous chondrite. Like other CMs, Mukundpura is matrix-enriched and has experienced different degrees of aqueous alteration with evidences of fracturing and compaction of clasts due to the impact. A few relict chon...

The relict intertidal deposits from the Kharod River Estuary, Gulf of Kachchh, and the distal end of Kori Creek are used to infer the Mid-to Late Holocene relative sea-level (RSL) change in western India. Employing sedimentology, geochemistry, palynology, ichnology, and optical and radiocarbon dating, the study suggests the dominance of fluvial act...

The presence of fluids promotes strain softening, and profoundly affects the evolution of shear zones. The Main Central thrust (MCT) is a major shear zone that accommodated at least 90 km of shortening, and played a significant role in Cenozoic evolution of the Himalaya. Surprisingly, no information exists on the role of fluid in evolution of the M...

This study attempted to probe a geologically more stable IR stimulated luminescence signal (IRSL) that explored so far. IRSL, probes the proximal pairs and, pIRSL measurements at elevated temperatures consume more distant pairs. We surmised that the residual IRSL after pIR-IRSL should arise from most distant pairs and hence should be more stable. A...

We investigated the textural-compositional characteristics across olivine interfaces in variably serpentinized olivine-gabbro samples dredged from the “Vityaz Megamullion” in the northern Central Indian Ridge (CIR). The results are used to understand the role temperature and/or different chemical properties in infiltrating fluid (e.g. seawater/hydr...

Modern globalisation has escalated anthropocentric sources for heavy metal contamination in diverse natural habitats. Pernicious nature of heavy metals poses a major threat to all life forms in the environment. Heavy metals are not degradable like the organic pollutants but could be transformed to be persistent in a less toxic form. Microbes are th...

Morphological, sedimentological, and chronological evidence suggests the preservation of three glacial advances of decreasing magnitude in the Puche valley (near Leh), southern Ladakh Ranges. The oldest moraine of Puche Glacier Advance-1 (PGA-1) is optically dated to the early Marine Isotopic Stage (MIS)-2 (31.5 ± 3.3 ka) that persisted until aroun...

The legendary river Saraswati of Indian mythology has often been hypothesized to be an ancient perennial channel of the seasonal river Ghaggar that flowed through the heartland of the Bronze Age Harappan civilization in north-western India. Despite the discovery of abundant settlements along a major paleo-channel of the Ghaggar, many believed that...

Two hitherto unexplored settlements at Karim Shahi and Vigakot are reported from the uninhabited hyper-arid region of the western Great Rann of Kachchh (GRK), located near southern fringe of Thar Desert, Gujarat, NW India. The archaeological evidence, supported by radiocarbon and optical chronology indicate presence of settlement from the Early Iro...

Moraines, outwash gravel terraces, fluvial drapes and lacustrine sequences are used to infer the pattern of glacial fluctuations in the Saraswati valley (upper Ganga catchment). Located in transitional climatic zone between dry steppe of the Tibetan plateau in the north and sub-humid higher Himalaya in the south, the Saraswati valley has preserved...

This study reports, for the first time, Sr and Nd isotope ratios from the mafic rocks in the Manipur Ophiolite Complex (MOC), along with new elemental abundances to show the subduction zone influence. The initial ⁸⁷ Sr/ ⁸⁶ Sr ratios (for t = 127 Ma) range from 0.705230 to 0.709734. The initial ¹⁴³ Nd/ ¹⁴⁴ Nd and ɛ Nd t ( t = 127 Ma) range from 0.51...

To determine the chemical composition of minerals on planetary surfaces from spectroscopic data, it is required to establish the link between mineralogy, spectroscopy and chemical composition of rock forming minerals on Earth. To meet this requirement, we performed integrated mineralogical and spectroscopic (Visible-Near Infrared and micro Raman) c...

The present study investigates the relics of glacier advances and retreats in the transitional climatic zone of the Southern Zanskar Range, NW Himalaya in response to the temporal changes in the Indian Summer Monsoon (ISM) and mid-latitude westerlies. The study identifies four glacier advances which are named from the oldest to youngest as the Sout...

General Mineralogical and Petrological characteristics of Mukundpura CM 2 chondrite

Aqueous alteration of Mukundpura CM2 chondrite

The Vindhyan Supergroup of India, deposited in an intracratonic basin, is one of the important Proterozoic marine successions of the world that contains some of the most controversial Precambrian fossil discoveries. Despite their importance, the chronology of the host strata and global correlation of the events that occurred within the basin remain...

Geomorphic analysis and optically stimulated luminescence (OSL) ages from undated Lake Agassiz beaches and adjacent fluvial sediments on Riding Mountain in Manitoba provide insight into their early history. New OSL ages of 14.5±2.4 and 13.4±0.7 ka on the oldest (Herman to Norcross) beaches of Lake Agassiz near the Canada-U.S. border indicate that t...

We conducted comparative morphological analysis of gullies within two high-latitude Martian craters (Domoni and Maricourt) in the northern hemisphere of Mars with (1) the debris-flow gully systems in the Ladakh Himalaya and (2) Istok Crater in the southern mid-latitudes of Mars where water-bearing debris-flow deposits have been previously reported....

Mukundpura is a new CM chondrite fell near Jaipur, Rajasthan, India on June 6, 2017 at 5:15 IST. The fall was observed by local villager. According to eyewitness, the meteorite was fragmented into several pieces once the object hit the ground. Based on petrography, mineralogy and bulk composition, Mukundpura is classified as CM2 chondrite. The chon...

Luminescence dating at the stratified prehistoric site of Attirampakkam, India, has shown that processes signifying the end of the Acheulian culture and the emergence of a Middle Palaeolithic culture occurred at 385 ± 64 thousand years ago (ka), much earlier than conventionally presumed for South Asia. The Middle Palaeolithic continued at Attirampa...

Relict lake sediments situated within the transition of the lesser and higher central Himalayas show a persistent millennial to centennial-scale monsoon variability during the Holocene. Based on high resolution geochemical data supported by radiocarbon dating, six phases of enhanced Indian Summer Monsoon (ISM) with varying magnitude have been ident...

We identify and characterize the rock forming mineral using a newly installed, state of the art Scanning Electron Microscope integrated with Micro-Raman Spectrometer (SEM-Raman) at Physical Research Laboratory, Ahmedabad, India. The characteristic raman shifts (wave numbers) enable us acquiring the structural information and chemical fingerprint fo...

The alluvial successions in the northern Gujarat alluvial plain (western India) have been investigated for reconstructing the climatic fluctuations during the last 40 ka. Alluvial architecture and geochemical proxies indicate prevalence of a strengthened Indian SummerMonsoon (ISM)with fluctuations between the late Marine Isotopic Stage 3 (MIS 3; 37...

A single piece of meteorite fell on Kamargaon village in the state of Assam in India on November 13, 2015. Based on mineralogical, chemical, and oxygen isotope data, Kamargaon is classified as an L-chondrite. Homogeneous olivine (Fa: 25 ± 0.7) and low-Ca pyroxene (Fs: 21 ± 0.4) compositions with percent mean deviation of <2, further suggest that Ka...

We present the development of a CeBr3 gamma ray spectrometer with the primary objective of determining the abundance and distribution of Th, U, K, Fe, Al and Si by measuring gamma ray signals produced by radioactive decay, neutron inelastic scattering and neutron capture reactions in the energy region 0.03 to 8 MeV. The energy resolution of the CeB...

The present study in the middle Satluj valley explores the sedimentary records of past floods with an objective to understand the climatic processes responsible for their genesis. Based on lithostratigraphy, sedimentology, and grain size variability, 25 flood events are identified. The geochemical data indicate that the flood sediments were mostly...

Bioclastic carbonate deposits that formed because of a combination of nearshore marine, fluvial, and aeolian processes, occur along the Saurashtra coast and in the adjacent interior regions of western India. Whether these carbonates formed by marine or aeolian processes has been debated for many decades. The presence of these deposits inland poses...

The present study is an attempt to reconstruct the paleohydrological conditions during the mid-Holocene in the hyper-arid terrain of the northern Great Rann of Kachchh. Remote sensing, detailed field geomorphology, sedimentology, geochemistry and optical chronology suggests that the fluvial sediments fringing the Khadir Island were transported loca...

Red clays of Central Indian Basin (CIB) under influence of trace of Rodriguez Triple Junction exhibited chemoautotrophy, low temperature hydrothermal alterations and photoautotrophic potential. Seamount flank TVBC-08, hosting such signatures revealed dominance of aerobic anoxygenic phototroph Erythrobacter, with 93% of total 454 pyrosequencing tags...

Red clays of Central Indian Basin (CIB) under influence of trace of Rodriguez Triple Junction exhibited chemoautotrophy, low temperature hydrothermal alterations and photoautotrophic potential. Seamount flank TVBC-08, hosting such signatures revealed dominance of aerobic anoxygenic phototroph Erythrobac-ter , with 93% of total 454 pyrosequencing ta...

Introduction: Komar Gaon meteorite fell (26°56'98"N, 93°46'11"E) during the daylight (12:00 pm IST) on No-vember 13, 2015 in Komar Gaon village of Golaghat district of Assam, India. The single piece of stone has a mass of ~12 kg and the local villagers witnessed the trail and subsequently observed its impact on a well ploughed field forming a 45 cm...

Detailed geomorphological investigation supported by field stratigraphy and optical dating enabled us to identify three major events of glaciation in the eastern Zanskar Himalaya (Sarchu Plain). The oldest and most extensive glaciation is the Sarchu Glaciation Stage-1 (SGS-1) that pre-dates the Last Glacial Maximum (LGM) and is assigned to the cold...

We present the development of a cerium-doped lanthanum bromide (LaBr3 : Ce) gamma-ray spectrometer (GRS) with the primary objective of determining the abundance and distribution of Th, U, K, and other major elements, including Fe on the entire planetary surface by measuring gamma-ray signals produced by radioactive decay, neutron inelastic scatteri...

Fluvial landforms in the Pindar River valley are investigated to understand the role of temporal variability in the Indian Summer Monsoon (ISM) and the spatial changes in crustal deformation. Employing the conventional geomorphological and sedimentological concepts, supported by optical dating, three major phases of valley-fill aggradation separate...

Detailed field mapping of glacial and paraglacial landforms supported by optical and radiocarbon dating is used to reconstruct the history of late Quaternary glaciation and landform evolution in the Trans Himalayan region of the upper Dhauliganga valley. The study identifies four events of glaciations with decreasing magnitude which are termed as P...

Sewage water is becoming a key source of heavy metal toxicity in large river systems worldwide and the two major Himalayan Rivers in India (Ganga and Yamuna) are severely affected. The high population density in the river banks combined with increased anthropogenic and industrial activities is contributing to the heavy metal pollution in these rive...

The present study is based on the field observations and geochemical analyses of flood sediments to ascertain the nature and causes of destruction in the Mandakini and Alaknanda river valleys during June 2013. The study suggests that the sediments were contributed from two major sources: the moraines and alluvial fans located in the Trans and Highe...

Pindar river in the Central Himalaya, drains through the steep climatic gradient and cut across multiple structural domains before meeting the trunk river. The river drains across the southern mountain front which is an orographic barrier for the northward penetration of Indian Summer Monsoon. Fluvial landforms respond sensitively to the spatial an...

This study attempted to probe a geologically more stable IR stimulated luminescence signal (IRSL) that explored so far. IRSL, probes the proximal pairs and, pIRSL measurements at elevated temperatures consume more distant pairs. We surmised that the residual IRSL after pIR-IRSL should arise from most distant pairs and hence should be more stable. A...

Dry land fluvial system in western India emanates from the Aravalli ranges and drains into the Gulf of Cambay and the Gulf of Kachchh. The sedimentary characteristics and textural attributes of the incised alluvial sequences in various river basins of western Indian indicate significant variability in the palaeohydrological conditions. Considering...

Field stratigraphy and optical and radiocarbon dating of lateral moraines in the monsoon dominated Dunagiri valley of the Central Himalaya provide evidence for three major glaciations during the last 12 ka. The oldest and most extensive glaciation, the Bangni Glacial Stage-I (BGS-I), is dated between 12 and 9 ka, followed by the BGS-II glaciation (...

The Newania carbonatite complex of India is one of the few dolomite-dominated carbonatites of the world. Intruding into Archean basement gneisses, the rocks of the complex have undergone limited diversification and are not associated with any alkaline silicate rock. Although the magmatic nature of the complex was generally accep- ted, its age of em...

Red sand dunes occur in the coastal plains of south east and west of Tamil Nadu, India between the coordinates of 8°00′ to 9°30′ N; 77°18′ to 79° 00′ E. OSL dating of these sands indicated aggradations between ∼16-9 ka and ∼9-3 ka in the west and east coasts respectively. Dating results from inland red dunes at the foothills of Western Ghats show a...