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The paper pertains to the studies carried out on the eclogitic xenoliths of KL-2 kimberlite of Kalyandurg kimberlite cluster in south India. Petrographic studies revealed bi-mineralic and kyanite-bearing eclogitic xenoliths in KL-2 kimberlite. The bimineralic and kyanite-bearing eclogites of Kalyandurg KL-2 kimberlite pipe show variation in modal proportion of garnet, omphacite, clinopyroxene and kyanite. The paper reports discovery of native gold grains and Au-Pt alloy in the kyanite-bearing eclogite xenoliths of KL-2 kimberlite. The flaky gold grains occurring in the matrix of kyanite-bearing eclogite are homogeneous and two grains of Au-Pt alloy with Au and Pt in the proportion of 9.8:1.2 are also present. This is the first report of gold and gold-platinum alloy specs from eclogitic xenoliths of Indian kimberlites. [ABSTRACT FROM AUTHOR]

Information about workshop "Western Ghats; Evolution and environmental issues" organised by research centre National Centre for Earth Science Studies (NCESS) on 1-2 January 2016 is presented. Topic included understanding knowledge gap between geoenvironmental issues, geological evolution and resource management of Western Ghat. Workshop featured three technical seasons including theme Western Ghats-A climate regulator, discussion over presented papers and forestry of Western Ghats.

The Jara dome in the western part of the Kachchh basin is the distal-most exposure of the Callovian to Aptian age sediments of the Kachchh stratigraphy. These outcrops are represented by three formations, namely, the Jumara, Jhuran, and Bhuj formations. The central part of this dome is represented by the entire succession of the Jumara Formation (Member-I to IV). This paper aims to document ichnofabric changes in the distal part of the basin during a basinal-scale transgression. The Jumara succession at the Jara dome is represented by finer sediments compared with the other coeval sediments across the basin. Ichnofabric analysis of the Jumara Formation at the Jara dome implies 21 ichnospecies from 12 ichnogenera with the reconstruction of ichnofabric constituent analysis for all four members. Member-I implies low diversity-low density trace fossils with a simple tiering profile. Member II is two thick bands of marls rich with high diversity and density occurrence of Zoophycos. Ichnofabric analysis suggests slow sedimentation in the shelf environment below the Storm wave base under dysoxic conditions. Ichnofabric analysis of overlying Member III suggests deposition below the fairweather wave base with well-oxygenated, shifting substrate-type environments. Ichnological analysis of Member IV (Dhosa oolite Member) suggests that a transgression event was inferred at Jumara Dome. Thus, the ichnofabric analysis of the Jumara Formation suggests an increase in ichnodiversity steadily from member-I to III and then a decline. A comparison of the Jara dome ichnology data with other coeval sediments of the Kachchh basin suggests high diversity in the Jara dome area. [ABSTRACT FROM AUTHOR]

Granitoids are well exposed in Jirang-Patharkhamah area (latitude N 25°57′− 25°41′ and longitude E 91°30′–91°38′). The area lies mostly in Ri-Bhoidistrict and is also extended to West Khasi Hills district of Meghalaya. The granitoids are medium grained and nonporphyritic. The colour is dominantly grey although some granitoids are pink in colour. The common minerals in order of abundance are quartz, plagioclase, K-feldspar, biotite and hornblende. Secondary minerals are sericite, chlorite, muscovite, secondary hornblende and secondary biotite. Among accessory minerals, sphene, zircon, apatite, calcite, zoisite, magnetite and monazite are significant. The intergrowth textures such as perthite, myrmekite in these rocks indicate that the rocks were affected by low temperature alteration. The representative samples ploy in the field of granite in various geochemical discrimination diagrams. The aim of the present paper is geochemical characterisation of the granitoids using major and trace elements (including REE). The whole rock geochemistry reveals that the granitoid is I-type, calc-alkaline, metaluminous to weakly peraluminous and an attempt is made to examine the nature of the magma based on biotite mineral chemistry. The biotite chemistry indicates that the granitoid is I-type and calc-alkaline. The paper also aims to estimate temperature of emplacement of granitoids based on two feldspar geothermometer and Ti-in biotite geothermometer. The temperature calculated from two feldspar thermometry is in the range 512–602°C and the average is 550°C. The temperature calculated by Ti-in biotite thermometer is in the range 623 to 656°C and the average is 645°C. Geothermometric results plays an important role in definition of petrogenetic history and regional tectonism. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive account on the evolution of the Tertiary Himalaya coals of India and their various attributes. The coal bearing sequences in Himalaya have formed in two different geotectonic settings, first under foreland basin (Oligocene coals of Assam, Nagaland and Arunachal Pradesh of northeastern India) and second under Platform basin (Eocene coals of Meghalaya of north-eastern India) conditions. The Jammu coals of northwest India developed in the late Paleocene in the western Himalayan foreland basin. A sea transgression inundated the Jammu area which gave rise to forest swamp and Jammu coals eventually formed under tropical humid climatic conditions in the tropical climatic belt of northern hemisphere. In northeastern India, the Oligocene coals have shown more maturity than the Eocene coals and have relatively high carbon content and they also have developed caking characters in many coalfields. This may be because the Eocene coal developed in the tropical climatic belt when the northern part of the northeast India was still in the southern hemisphere and the Oligocene coal evolved when the northern part of the northeast India was in the northern hemisphere and the collision during the Oligocene in this part improved the maturity of Oligocene coal due to Himalayan orogeny. The Himalayan coals are exceedingly rich in vitrinite with variable quantities of liptinite and inertinite macerals. Dominance of typical Tertiary angiospermic floral assemblage in the Himalayan coals is well indicated by the occurrence of single, double and triple celled telutospores. [ABSTRACT FROM AUTHOR]

The present research study aims to analyze flood frequency to relate flood magnitudes with corresponding return periods. These estimates are crucial for the development of flood-preventive hydrological infrastructures and flood plain zoning, etc. Basin-wide high intensity of rainfall and high discharge from the upper riparian region during monsoon months creates flooding in the middle and lower reaches of the Ghagra River basin. Therefore, the flood estimates for three gauging sites situated on the mainstream of the Ghagra River viz., Elginbridge, Ayodhya, and Turtipar, have been comprehended using the Gumbel distribution (Extreme Value Type I) method and the Log-Pearson Type III distribution method. Flood estimates are calculated for 1.01, 1.05, 1.11, 1.25, 2, 5, 10, 20, 50, 100, 200, and 500 years return periods considering flood time series of 50 years to reduce estimation uncertainty. The findings of flood frequency analysis (FFA) revealed that the probability of occurrence of the flood is more than 80% at all three sites because Ghagra River can carry around 7800 to 9000 m3/s of water discharge without posing a high risk of levee break. The upper and lower limits of discharge carrying capacity depend on the river's desiltation process. Hence, the flood occurs almost every year in the basin; its only variation is its severity. The rainfall-runoff relationship is estimated by integrating a simple linear model and for rainfall trend analysis Mann-Kendall is applied. Linear regression analysis-based rainfall-runoff relationship outcomes revealed a significant relationship with a positive correlation coefficient i.e., 0.2722 for Elginbridge, 0.39624 for Ayodhya, and 0.4844 for Turtipar gauging site in the monsoon season but other factors like a high amount of water discharge from dams in upper riparian regions, etc. are also responsible for flooding in the middle and lower reaches. The Mann-Kendall trend analysis shows a decrease in annual average rainfall and rainfall in the monsoon season. Discharge variability indicates the direct relationship between flood fury and changes in climatic patterns in recent decades. This paper identifies that future research is needed to better inform the policy planners who strive to design sustainable infrastructure. [ABSTRACT FROM AUTHOR]

The documentation of excavation method and support design based on rock mass classification systems i.e. rock mass rating (RMR), Q-system and New Austrian tunneling method (NATM) for adit-7 tunnel being constructed in Garhwal Himalaya, India is discussed in this paper. The New Austrian tunneling method classes of rock units have been developed by using correlations with the RMR and Q systems, according to the ONORM B 2203. NATM principles were used because the geological conditions were continually changing. The study indicated that the RMR-based rock mass estimation was overstated, but the qualitative assessment was right. The NATM technique is more adaptable for Garhwal Himalayan rocks having various uncertainties in rock mass evaluation. The current adit investigations indicate that there are numerous unanswered concerns, concerning rock mass quality evaluation, tunnel behavior during construction and usability. Results of the analysis are considered to be useful for the design of the new tunnels constructed in the similar type of the terrain. [ABSTRACT FROM AUTHOR]

The study considers the impact of the degree of weathered material constituting the sedimentary rocks on the strength of the Lower Gondwana coal measure rocks. The dependence of the strength of primary rocks on the alteration indices has been previously studied, but it is unknown for secondary/sedimentary rocks. Therefore, in this paper, Lower Gondwana coal measure rocks (sandstone and shale) from the most productive coalfields of India, the Barakar and Raniganj coalfields, have been studied geochemically and geomechanically to find out their correlation. Geochemically, the study revealed that an arid, non-marine, and deltaic depositional environment prevailed during the sedimentation of Barakar and Raniganj Formations. The provenance was deduced to be mafic igneous. It was also deduced that the Lower Gondwana sandstone is clay-rich, and the sandstone samples fall in the shale field in the chemical classification scheme for terrigenous clastic sediments. The weathering indices, along with the uniaxial compressive strength (UCS) of the Barakar and Raniganj Formation coal measure rocks, have been assessed. The dependence of UCS on the weathering indices has been evaluated, and positive relationships were obtained. [ABSTRACT FROM AUTHOR]

India is endowed with unique geological and tectonic setting conducive to host potential mineral resources. A look at the mineral resource status of selected minerals in India indicates abundant and/or adequate resources of iron, chromite, manganese, bauxite, coal, limestone, dolomite, mica, zinc, graphite but deficient to scarce resources of nickel, cobalt, molybdenum, copper, sulphur, potash, apatite, rock phosphate, gold, PGE's, diamond etc., in spite of the vast obvious geological potential (OGP) blocks that exist in India. The OGP blocks have been estimated to around 1 lakh Km2 for gold, 3 lakh Km2 for diamond, 1.6 lakh km2 for base metals, 8000 km2 for PGEs and 5000 km2 for iron ores. By a rough estimate only 10% of this is explored and less than 2% is mined. The Reserve to Resource ratio which, as per mineral exploration practice, should be over 50% is woefully low for most of the minerals. For instance it is 17% for bauxite, 14% for copper, 24% for iron 14% for lead-Zinc, 8% for limestone and 30% for chromite etc. This calls for highly focused exploration strategy at high confidence level. India need to take a leaf out of strategies of many other countries and frame her own policy based on OGP areas to trigger the mining growth by accelerating mineral exploration programme. Benefits that flow from the mineral exploration/mining sector have huge impact on local populace, industry especially mineral dependent industries, employment and overall prosperity. Recent amendments in the Mines and Minerals (Development and Regulations) Act-1957 in the year 2021, have sought to bring out the potential of the mineral sector such as to increase the revenue of the State, escalate employment, maintain the continuity of mining operation, increase production, time bound operationalization of mines, increase the speed of exploration and auction of mineral resources and lastly to resolve the long pending issues that have decelerated the growth of this sector. This is an encouraging step and likely to bear fruits. These legislative and policy reforms in the mineral exploration and mining sector have laid down a sustainable road map that aims to boost mineral output by 200% in the next 7 years and raise the GDP contribution to 2.5%. Mineral laws Amendments Act 2020 are transformative and investor friendly. Mining is now defined as legal entity and hence seamless transfer of mining lease is possible. New auction mechanism instituted will ensure transparency, eliminate discretion, reducing bureaucratic delay and easier trading of mineral rights. Setting up of District Mineral foundation (DMF) will work for the interest and benefit of mining related operations and overcome the local resistance to the mineral exploration and mining activities. The National Mineral Exploration Trust (NMET) will focus on extending more financial assistance to government and also the private sectors to augment advance technology and will surely give fillip to exploration initiatives. The paper deals with such ideas in relation to the required thrust in mineral exploration sector in Indian context. [ABSTRACT FROM AUTHOR]

Minerals and metals are crucial raw materials for industries and a major source of development for the country. In India there has been a pronounced growth in the exploration for minerals both in terms of quantity and value. To further enhance the growth rate and remove any bottleneck, the government has taken several legislative reforms through more transparency and non-discretion by way of first-come, first-served basis in the allocation of mineral concessions, through Mines and Minerals (Development and Regulation) (MMDR) Amendment Act, 2015. Recently, MMDR Act, 1957 has been amended through the Mines and Minerals (Development and Regulation) Amendment Act, 2021 vide notification dated 28.03.2021 for improving ease of doing mineral production and business in the country and help increase Gross Domestic Product (GDP). Exploration of energy-critical minerals, fertilizer minerals, precious metals and stones, strategic minerals and deep-seated minerals which are otherwise difficult to access and for which the country is mainly dependent on imports, needs to be prioritized. Enhanced exploration and mining can significantly reduce India's import dependence on mineral and metals and help economic growth. For comparison, only 10% of obvious geological potential (OGP) area of India has been explored while Australia has explored more than 90% of its area. In this paper, some of these legislative reforms and challenges to provide an impetus to mineral exploration are discussed. [ABSTRACT FROM AUTHOR]