Ranadhir Mukhopadhyay

• PhD
• Principal Investigator at National Institute of Oceanography

The Indian Ocean Region (IOR) is a prominent arena in international politics, in terms of trade, tourism, population, among other aspects. Several countries, some unconnected geographically, have shown interest in these waters. These entities offer financial, technical, infrastructural and capacity-building support, and security services to several...

This poster is a work on the Geochemistry of North Comorin Ridge. It tells us about the episodic eruption history of Comoin Ridge, which gives us a better insight on the India-Magasgascar-Seychelles continental separation.

Because of ever-growing demand for strategic metals, the focus of the international community has fallen on deep sea manganese nodules occurring at a water depth of more than 4500 m. We present an economic appraisal and strategy for mining of nodules from the Indian Ocean Nodule Field- one of the four economically potential areas in the world ocean...

We present here a scenario of magmatic and tectonic processes associated with the interaction between the Reunion mantle plume and the mantle beneath Central Indian Ridge (CIR) at the Vema Trench (VT) along the Vema Fracture Zone (VMFZ) in the Indian Ocean. The VMFZ offsets the CIR by about 300 km between 8°S and 10°S latitudes and holds probably t...

Dismemberment of the Gondwanaland, India’s accelerated movement towards north, and formation of Himalayas are some of the unique characteristics of the Indian Ocean that shaped its dynamics- physical, chemical, biological and geological, understanding of which remains a legacy of last 50 years of research. In fact, a number of seemingly unrelated g...

In order to ascertain the effect of geomorphic and tectonic domains on the formation, enrichment, and ascension of the ridge axis melt, structural and petrological data from a nearly 300-km-long axial stretch along the slow-to-intermediate-spreading (40–60 mm/year) southern Central Indian Ridge (SCIR) were studied. The stretch, approximately betwee...

The nearly 7500 km long coastline of India is remarkably varied and dynamic and displays diverse rock-based, sediment-based and coral-based coastland landforms. Coastal processes along the Indian coasts are controlled largely by monsoons. The Arabian Sea coast differs from the Bay of Bengal coast in several respects. The east coast is wider, with s...

The formation and evolution of the ∼600 km long arcuate Amirante Ridge and Trench Complex (ARTC) is a significant geomorphic–structural feature in the Western Indian Ocean (WIO). The WIO contains evidence of at least two major magmatic episodes followed by continental rifting within the span of a little more than 20 million years. This involved the...

The architecture of the western continental margin of India (WCMI) is likely to have been influenced in the geological past by several episodes of volcanic eruptions, rifting, and continental break-up. The WCMI is characterized by a wide shelf in the north (few hundreds of kilometers wide), which tapers down to just few kilometers towards the south...

The ferromanganese nodule resources of the Indian Ocean Nodule Field (IONF) are second only in the world in terms of metal content and abundance. Since it was made known by Mero (1965) that several trillion tonnes of manganese nodules lay in the world oceans, extensive exploration for nodules has been undertaken during the last four decades. The po...

This chapter discusses the indian ocean nodule field (IONF). The Indian Ocean constitutes about one-seventh of the earth's surface and is the world's third largest water body. This ocean covers an area of 73.6 million km2, and is separated from the Atlantic and the Pacific oceans by roughly 20°E and 147°E, respectively. The plate boundaries of vari...

Volcanic activity generally forms a complementary component contributing toward the structural and morphotectonic features on the seafloor. The central eruptions are mainly confined to the bottom of ocean basins, and largely create abyssal hills and seamounts, while K-poor tholeiitic normal mid-ocean ridge basalt (NMORB) erupts along the fissures....

This chapter discusses the distribution, the grade, and the processes of formation of ferromanganese deposits (both nodules and crusts) during the last 5-10 million years. Acoustic and physical properties of indian ocean nodule field (IONF) nodules are studied in detail, in both dry and wet conditions. The non-destructive sound (acoustic) propagati...

This chapter focuses on the tectonic and geomorphological characteristics of indian ocean nodule field (IONF). The ridge-normal structural lineaments in the IONF are largely oriented N-S to NNE-SSW, and lay perpendicular to the present-day southeast indian ridge (SEIR). Among the ridge-normal lineaments, the Vishnu FZ (along 73°E), Indrani FZ (alon...

Resources need to be mined and used in a continuous and sustainable manner without causing any (or least possible) harm to the environment, biota and human life. This chapter describes the equipment used for exploration, different mining methods, and assesses the environmental implications concerning mining. It discusses the metallurgical technique...

Integrated geological and geophysical explorations over the last two decades along the central western continental margin of India reveal, from east to west, a terrace-like flat shelf, an advancing shelf break, a NW–SE-oriented wide shelf margin basin, the Upper Slope Ridge, the Prathap Ridge and the Laccadive Ridge. The basin on the continental sl...

This book briefly accounts for the physiography, geology, biology, physics and chemistry of the nodule field, and discusses in detail the aspects of structure, tectonic and volcanism in the field. The role of the ocean floor sediment that hosts the nodules and crusts are presented. The nodules and crusts are exhaustively described and their genesis...

We report the occurrence of ferrobasalts recovered from the Central Indian Ocean Basin crust generated at the Southeast Indian Ridge during a phase of moderate to fast spreading accretion (~110-190 mm/yr, full rate).The rocks are rich in plagioclase, FeO* (13/19 %), and TiO2 (2.27/2.76 %), poor in olivine and MgO (3.44/6.20%), and associated with t...

Analogous to other subduction zones in the world where the heavier oceanic plate shoves below the lighter continental plate, crustal movement along the Sumatra–Andaman trench line over the last two centuries released enormous stress causing earthquakes of highest impunity and generating, at times, devastating tsunamis. Such significant earth moveme...

We attempt here to quantify and model physiographic phenomena off the central west coast of India in terms of power spectral exponent, amplitude parameter. The statistical analysis of the multibeam echosounder grid bathymetry data is able to characterise the outer shelf, upper slope, shelf margin basin, and several structural rises. The scatter dia...

The >M9 earthquake of 26 December 2004 (26/12) that generated devastated tsunami was probably occurred by a combination of three tectonic movements- dip-slip at Sunda trench, strike-slip along the boundary between India and Australian plates, and uplift of western Burma plate. Accepting the fact that natural hazards can hardly be stopped or moderat...

In this article, we chronicle the events that lead to the creation of a global scientific network for midoceanic ridge research, identify areas where Indian researchers could participate and built a case to support and gain momentum within the country for the young, emerging InRidge programme.

Multi-beam and single-beam bathymetric, gravity and magnetic data, across seven ridge segments (length varying between 37 and 84 km), offset by six transform discontinuities (ranging in dislocation length between 48 and 344 km) of the Northern Central Indian Ridge (NCIR) were collected. Four Transform Faults (TF, viz. Sealark, Vityaz, Ehrlich and V...

The Indian Ocean Nodule Field (IONF) is significant from several points of view. Roughly bordered by 10°S to 16°30′S and 72°E to 80°E and located within the Central Indian Ocean Basin (CIOB), the field hosts the world's second largest and second high grade manganese nodule deposit, after the equatorial nodule belt in the north Pacific Ocean. Moreov...

The Himalayas are a complex, uplifted and deformed mountain range, brought about by tectonic activities, culminating in a series of plate collisions, most of which are still currently active. The Indo-Eurasian Plates’ collision event of the Tertiary times finds expression in intense deformation and associated metamorphism and magmatism in the Himal...

In this book, the underwater mineral resources are described, and the distribution of minerals in different physiographic segments, from the coastal belt up to the deeper part of the ocean, is considered. Marine mineral exploration, deep-sea mining, legal aspects of ownership of resources in areas beyond the exclusive economic zone (EEZ) in the ope...

Studies on the Indian Ocean Ridge System, though sporadic, was aimed to map the complete IORS petrologically and tectonically. Three areas are placed for immediate investigation; one in the slow spreading Carlsberg Ridge area, the second, along the intermediate spreading Central Indian Ridge, and the third one at the Andaman back-arc basin. The Nat...

The first cruise under India's own Ridge research initiative, InRidge collected new data on bathymetry, free-air gravity and magnetic anomalies across the ridge axis between the Vema and Zhivago transform faults in the Central Indian Ridge. In addition, basalt and ferro-manganese nodules were collected from the Vityaz transform fault area. Basalts...

We report the occurrence of ferrobasalts recovered from the Central Indian Ocean Basin crust generated at the Southeast Indian Ridge during a phase of moderate to fast spreading accretion (∼110–190 mm/yr, full rate).The rocks are rich in plagioclase, FeO* (13–19%), and TiO2 (2.27–2.76%), poor in olivine and MgO (3.44–6.20%), and associated with top...

Intraplate volcanism in the Central Indian Ocean Basin (CIOB) has been of much interest, since this tectonically young and structurally complex basin holds signatures of at least one major plate reorganisation at 65±5 Ma; and two major plate boundary structural deformations occurring at 54.5±3 Ma (collision of India with Eurasia) and at 7 Ma (intra...

The nature of magnetic anomalies and associated ridge-parallel structural lineaments and topographic complexities from an area bounded by latitudes 9 °45′S and 14 °45′S in the Central Indian Ocean Basin (CIOB) suggest that the underlying crust was generated from the South East Indian Ridge (SEIR) between 60 and 50 Ma. The multibeam bathymetry revea...

Previous studies on the distribution and morphology of ancient seamount chains (> 50 Ma) in the Central Indian Ocean basin (CIOB) indicated their generation from the fast spreading Southeast Indian Ridge. Here we describe the petrology of some of these seamounts. Fresh glass veneers of pillow basalts from these seamounts were analyzed by electron m...

We report here the occurrence of, to date, the largest (21 10 8 mm) phillipsite crystal forming the nucleus of a diagenetically formed ferromanganese nodule from the Central Indian Ocean Basin (CIOB). Assuming an average rate of ferromanganese nodule accretion as ~ 2 mm/Ma and that of phillipsite growth as ~ 0.65 mm/Ka, the nucleus material appears...

Hydrosweep mapping of crust in the Central Indian Ocean Basin reveals abundant volcanoes ocurring both as isolated seamounts and linear seamount chains parallel to flow lines. Their shapes, sizes and overall style of occurrence are indistinguishable from near-axis seamounts in the Pacific. Evidence from seamount morphology, distributions and petrog...

Distribution and mineralogy of various rock types along the 4200-km-long slow-spreading Central Indian Ridge, between Owen fracture zone in the north and Indian Ocean triple junction in the south, is studied in the light of ridge segmentation, and associated stress regime. To understand such phenomena along an extremely low magmatic budget spreadin...

The Central Indian Ocean Basin (CIOB) was subjected to tectonic reactivation in geological past which is unusual for a basin occurring on an apparently single tectonic plate. ENE-WSW trending latitude parallel zone of reactivation across the central part of the basin is reported. Distinct difference in characters of seamounts, manganese nodules and...

Manganese nodules from the Central Indian Basin (5 degrees-10 degrees S) vary in abundance, morphology, mineralogy, and chemistry with water depth and sediment type. Nodules from the southern region, dominatEd. by siliceous sediment, differ markedly from northern and central region, dominatEd. by terrigenous and terrigenous-siliceous mixed sediment...

Morphological, chemical, physical and acoustic properties of Mn-nodules in the the Indian Ocean are inter-linked and depend much on local and regional oceanic environments. These nodules are anisotropic and sound propagation is faster parallel to their elongation. Denser nodules show low attenuation. Density and P-wave velocity in nodules increase...

The study of seamount parameters in the tectonically most-complicated and least-understood Indian Ocean assumes importance since their properties vary as a function of tectonic setting, physics of lithosphere, conduit geometry and chemical composition of magma. More than 100 such seamounts ranging in summit height (h) from 300 to 2870 m, are indent...

Studies on acoustic properties of manganese nodules from pelagic and siliceous clays and calcareous ooze sediment regions in the Central Indian Basin suggest that smaller nodules are more anisotropic than the larger ones. Larger nodules are mostly abundant in siliceous clay area and have a low density, low porosity, a high concentration of Cu coupl...

The morphology and chemistry of ferromanganese nodules and encrustations from a seamount in the Central Indian Ocean Basin show local variations. Nodules from the summit of the seamount have sporadic distribution, are less spherical, have smooth surfaces, have lowest oxide/nucleus (O/N) ratios, and contain low values of Mn/Fe, Ni and Cu. In contras...

Polymetallic nodules from the Central Indian Ocean largely range in size from 2 to 6 cm. The smaller nodules (<4 cm) are subspheroidal to spheroidal in shape and with the increase in size, nodules become more discoidal and elongated. The size and relief of mammillae vary with the size of nodules. Polynucleate nodules are more abundant in larger siz...

Mauritius has the great potential to harness resources from the ocean. This would require reduction in the distance between the majestic beach cultures to serious R&D activities. With the formation of Mauritius Oceanography Institute, the effort received a boost and created sustainable movement for ocean research in the country. Under the banner of...

Distribution and morphology of volcanic seamounts from an area of 84572 km super(2) in the Central Indian Ocean Basin (CIOB) using multibeam bathymetric system are presented here. The study area is boundEd. by two NNE-SSW oriented structural lineaments and is infested with about 800 seamounts of various height ranging from 50 m to 1250 m. Statistic...