Indicator Of Deposition Research Articles

Report on Book Release: “Rare Earth Element Occurrences and Deposits of India and Strategies for New Discoveries” by P. Krishnamurthy, Geological Society of India, Bengaluru

Report on Book Release: “Rare Earth Element Occurrences and Deposits of India and Strategies for New Discoveries” by P. Krishnamurthy, Geological Society of India, Bengaluru

Fractal dimension and its implication to mineral exploration: a case study from the Jonnagiri and Gadag gold deposits in India

Fractal dimensions characterize the spatial distribution pattern of mineral deposits, allowing the mineralization processes beneath and at the surface to be understood. This study considered a mineralized vein along the fracture/shear zone near the Dona Temple in the Jonnagiri gold deposit and borehole data from the Sangli Block in the Gadag gold deposit. The above-mentioned zones were considered using fractal dimensional analysis to constrain the fluid-flow pathways. The box-counting technique was used to measure the fractal dimension of the mineralized vein along the surface from a detailed to a regional scale. The fractal correlation integral method was used to provide the fractal dimension values from the gold assay (in g t −1 ). The box-counting fractal dimension values obtained varied from 1.07 to 1.36, whilst the fractal dimensions obtained from the fractal correlation integral method ranged from 0.03 to 1.97. Higher fractal values signify a fully matured interlinked fracture/fault network with steep fluid-flow pathways, while lower values indicate the converse condition. Further, the study showed that the fractal analysis of the mineralized vein along the fracture/shear zone appeared to correlate with the fault system rather than with the litho-contact. Economic gold deposition occurs mainly along a structure with a steep fractal gradient, which is the target area for economic gold exploration.

Lithocodium mound identification using logging-while-drilling image log and quantified cutting analysis — Validation with analogues

Lithocodium mounds are early Cretaceous sedimentary structures described in the literature from outcrops, however, never described in the subsurface. The objective of this work is to identify and characterize Lithocodium mounds in the subsurface along a 25,000 ft horizontal well. Drill cuttings sampled at a 100 ft interval are observed in thin sections to define and quantify key sedimentary indicators (bioclasts, facies, and texture). Logging-while-drilling (LWD) gamma ray (GR), density, neutron, and resistivity logs are acquired along with the LWD high-resolution borehole image (BHI) log. Bedding dips from BHI data, interpreted along the horizontal well, enabled the reconstruction of the reservoir paleotopography. In particular, the alternation of dip azimuth combined with the facies interpretation from the thin sections supported the interpretation of eight distinct mound structures. An assessment of their overall geometry confirmed the mound shape to be subcircular, consistent with the subcircular geometries observed in Oman at the outcrop. The inferred dimensions of the mounds are comparable with the Aptian Lithocodium mounds in Oman (30–40 m), and their intermound organization resembles that of the Albian mounds in Texas. This work demonstrates the value of analyzing cuttings to complement image log interpretation and the value of outcrop analogues for interpreting sedimentary structures. For the first time, the subsurface identification and characterization of Lithocodium mounds and intermounds are achieved.

Reducing uncertainty in source area exploration of mineralized glacial erratics using terrestrial cosmogenic radionuclide dating

Mineral exploration often relies on sedimentary indicators as first signs of a potential nearby mineralization in bedrock. The transportation of sediment by glacial and fluvial processes introduces uncertainty into the tracing of potential source areas of the sediment. This is particularly challenging in areas where glacial erosion has been weak, resulting in reworking of sediments and multiple directions of transportation. In this study we explore the use of Terrestrial Cosmogenic Nuclides (TCN) alongside conventional mineral exploration methods to better link indicators with their potential source areas.The study focuses on a mineral exploration project site in northern Finland in a region with stratigraphic evidence of multiple glaciations. The project targets the source of discovered Au mineralized erratic boulders that have been deposited atop the most recent till unit. The superposition suggests transportation in the latest glacial event. However, the 10Be (35.9 ± 1.3 and 30.3 ± 1.1 ka) and 26Al TCN ages analyzed from the mineralized erratics precede the latest glacial event, suggesting the possibility of multiple stages of transportation. The local bedrock TCN inventories (48.9 ± 1.9 and 85.3 ± 2.8 ka) are well preserved, suggestive of weak glacial erosion and therefore short recent transportation distances for the mineralized erratics. By combining the TCN interpretation and historical ice flow directions derived from the till stratigraphy, we suggest a nearby source locating NNW of the dated erratics.We find that TCN dating can limit some of the transportation related uncertainties in glaciated terrain. Through the analysis of TCN inventories from bedrock and boulders it is possible to characterize glacial erosion and boulder transportation, and to identify repeated exposure events, i.e., the possibility of multi-staged transportation. The method benefits from combined use of stratigraphic investigations that can identify both the local transportation directions and local glacial coverage history. TCN sampling has a minimal environmental impact, can be used in remote areas and can provide information about the transport history already in the early stages of exploration. Although the analysis is time consuming, the survey is light to conduct and informative even with a small number of samples.

Site-Specific correlation between geotechnical and geoelectrical properties of soil deposits in India

The combined application of geotechnical and geophysical methods provides an effective means of subsurface exploration. The insufficient correlation between geotechnical and geophysical methods prevents the conversion of geophysical data to geotechnical information and vice versa. In the present study, a correlation has been proposed between the geotechnical and geoelectrical properties of two soil deposits in India. Eleven boreholes along with a Standard Penetration Test (SPT) and different laboratory tests have been conducted to obtain the different engineering and physical properties of the soil layers. Twelve Electrical Resistivity Tomography (ERT) profiles have also been conducted to obtain the resistivity profile of the subsurface layers. The variation of the resistivity of the soil layers is analyzed and explained. Results show a strong linear correlation between resistivity and SPT blow counts (N′) of the soil layer for one site while a weak correlation for another site. A strong linear correlation between transverse resistivity (T) and N′ values has been observed for both sites. A comparison with the other existing correlation between resistivity/transverse resistivity and N′-values has also been presented. The range of resistivity values and engineering properties of soil layers are mentioned. The study is useful for the development of similar correlations and provides an approximate estimation of different geotechnical parameters for infrastructure design.

Performance evaluation of Alccofine stabilised Marine clay as subgrade

Soil stabilization is a remedial measure that reduces permeability and compressibility, increases bearing capacity and shear strength of soil mass, which helps in reducing the settlement of structures. Marine clay is one of the major regional soil deposits in India, widely found in offshore and coastal areas. This is a type of low strength soft clay which majorly causes failure in pavements and foundation structures due to high settlements and low strength characteristics. The scope of this project is to improve the strength of marine clay by stabilizing it with alccofine. The work includes determination of index properties of marine clay by Hydrometer method, Atterberg’s test, Specific Gravity test, Free Swell test. The engineering properties of both virgin soil and soil stabilized with 3%, 6%, and 9% of alccofine are determined by various tests such as Standard Proctor test, California Bearing Ratio test. On the basis of CBR test, the optimum percentage of alccofine in marine clay is found out to be 6%.

A ∼5000 year multiproxy record of summer climate in NE Greenland

The High Arctic plays a vital role in Earth's climate system, and its ecosystems are highly sensitive to global climate change. High Arctic lakes are valuable sentinels of climate change, as their sediments integrate long-term natural climatic fluctuations and anthropogenic influences. Here, we present a high-resolution ∼5000 year-reconstruction of NE Greenland climate variability from Aucella Lake (74°N, 20°E) based on physical, chemical, and biological properties of lake sediments. We use CT-scans, hyperspectral imaging, organic matter, XRD, and diatom analyses to show that changing air temperatures were controlled by a mix of regional climatic changes and local landscape feedbacks. The latest Mid-Holocene (∼5.0–3.8 cal. ka BP) was characterized by relatively warmer conditions, while the onset of the Late-Holocene was marked by abrupt temperature decreases that coincided with the beginning of glacial advances elsewhere (∼3.8–3.4 cal. ka BP). From ∼3.4–2.4 cal. ka BP, the sedimentary record indicated progressive warming, with temperature peaking during the Medieval Climate Anomaly, although temperature rises were punctuated by abrupt, short-lived cold periods. From ∼1.1–0.05 cal. ka BP, the influence of landscape factors over the system diminished. Sedimentary indicators suggested a transition towards a colder, more humid climate, coinciding with the beginning of the Little Ice Age, that was characterized by a marked decrease in air temperature that reached minimum values at the end of this period. The last 50 years at Aucella Lake were marked by abrupt temperature rises, consistent with recently observed anthropogenic global warming. Our results illustrate the importance of high-resolution multiproxy studies for accurately characterizing lake linkages to their environment and climate.

Can Imaging Spectroscopy Divulge the Process Mechanism of Mineralization? Inferences from the Talc Mineralization, Jahazpur, India

Talc deposits of Jahazpur, Rajasthan, hosted by dolomite, are one of the largest high-quality talc deposits in India. In the present study, we use AVIRIS-NG datasets to study the link between the spatial pattern of talc mineralization, associated alteration minerals, and iron-oxide enrichment. It is noted that the majority of talc-bearing areas are characterized by the presence of clay minerals, such as an intimate mixture of kaolinite and muscovite, illite, dickite (indicative of phyllic and argillic alteration), and also enhanced iron enrichment. The talc-bearing zones are located adjacent to quartz-rich lithologies, and they are aligned along the Jahazpur thrust. Based on mineralogical and geological evidence, hydrothermal alteration of dolomites by silica and iron-rich fluid is proposed as major factorcontrolling talc mineralization. This study has implications for the identification of prospective zones of talc mineralization using imaging spectroscopy.

Geochemical record of methane seepage in carbon cycling and possible correlation with climate events in the Qiongdongnan basin, South China Sea

At cold seeps, sulfate-driven anaerobic oxidation of methane (SD-AOM) is the dominant biogeochemical process, which can significantly affect the marine carbon-sulfur cycle. In this paper, multiple sedimentary indicators in core QS-1 were reported for methane seepage from Haima seep of the South China Sea (SCS). By combining total carbon (TC), total organic carbon (TOC), total sulfur (TS), total inorganic carbon (TIC), as well as the carbon and oxygen isotope compositions of benthic foraminifera Uvigerina spp. In sediments, our aim was to explore the geochemical evidence on methane seepage activities in this area. We identified three methane release events (MREs) with different intensities and timescales during MIS 1–2, characterized by particular anomalies of negative δ13CTIC (as low as −41.42‰) and δ13CU.spp (as low as −5.50‰), high contents of TS and high S/C ratios, simultaneously. High S/C ratios and negative values of δ13CTIC effectively indicate the intense SD-AOM and SD-AOM-related process in core QS-1. Three MREs, occurred at high or low sea level, may due to the climate-driven increase of hydrostatic pressure and seafloor temperature. The insights for sediment carbon-sulfur trace element, carbon isotopes of TIC contents and benthic foraminifera have obvious implications for tracing past methane seepages and its possible link with climate changes.

Did a Late Paleoproterozoic-Early Mesoproterozoic Landmass Exist in the Eastern Cathaysia Block? New Evidence from Detrital Zircon U-Pb Geochronology and Sedimentary Indicators

The South China Craton comprises the Yangtze and Cathaysia blocks and is one of the largest Precambrian continental blocks in East Asia. However, the early geological and geographical evolution of the Cathaysia block is relatively poorly understood, due to the sparse exposure of pre-Neoproterozoic rocks and reworking during Phanerozoic polyphase magmatism and metamorphism. In this contribution, we carried out detrital zircon U-Pb geochronology and sedimentary analyses on five Proterozoic meta-sedimentary rocks collected from the northeastern Cathaysia block, which belong to the previously defined Chencai, Mayuan, and Mamianshan Groups (strata). LA-ICP-MS U-Pb dating results of the detrital zircons show various ~1.85–1.35 Ga maximum depositional ages. They are significantly older than the previously constrained Neoproterozoic formation ages of these Proterozoic strata of northeastern Cathaysia, suggesting that their deposition and formation were probably initiated as early as the late Paleoproterozoic. Provenance analyses reveal that the late Paleoproterozoic to early Mesoproterozoic detrital zircons with igneous-origin were derived from in situ contemporary crystalline basements in eastern Cathaysia. In addition, by implication, the easternmost part of Cathaysia was probably an emerged area (i.e., the “proto-Cathaysia Land”) under active erosion. It had a ~NWW orientation and provided detrital sediments to the neighboring marine basin (i.e., the Cathaysia Sea) during the late Paleoproterozoic to early Mesoproterozoic. Finally, the Paleoproterozoic evolution of Cathaysia was involved in the assembly of the Nuna supercontinent. Our results, together with the published data, reveal a distinct late Paleoproterozoic (~1.8 Ga) detrital zircon age peak, which seems to support the view that eastern Cathaysia had close tectonic affinities with terranes such as the Precambrian terranes of current northern India, in the framework of the Nuna supercontinent reconstruction.

A review of Palaeolithic sites associated with gravel deposits in India

Abstract Rivers and river-borne deposits have always been a major attraction for hominins as an important source of sustenance and settlements. Hence, fluvial deposits have long been an important source of evidence for early human occupation throughout the Old World. Apart from being an important palaeoclimatic marker, fluvial sequences have provided archaeologists with frameworks for correlation, along with Palaeolithic markers discovered within them. Moreover, given the influx of sediments eroded and deposited by Indian rivers, these could have acted as a centre of hominin activities. Palaeolithic research in India has been concentrated around some of its major river valleys, which have yielded a rich record of hominin occupation. So far, 305 Palaeolithic sites have been reported from a gravel context throughout the country, yielding Lower to Upper Palaeolithic, Mesolithic and Neolithic evidence. However, most of the derived evidence is secondary deposits and stands contested based on its contextuality. Nevertheless, its importance as a source of information about hominin activity cannot be underestimated. This review presents a provisional synthesis of all of the Indian Palaeolithic sites reported from gravel contexts, thereby presenting scope for future multidisciplinary research at these localities.

Seismic site characterization of a few Indian coal ash deposits using multichannel analysis of surface waves

This study presents the outcome of an extensive field experiment undertaken to characterize coal ash deposits in terms of dynamic properties. In-situ shear wave velocity ( V s ) was measured over three hydraulically deposited coal ash deposits (two active ponds and one abandoned pond) situated in the central and southern parts of India. Multichannel analysis of surface waves was performed at twenty-one different locations on the ash deposits and the dyke top to measure the V s profiles along the depth ( z ). V s profiles measured for the abandoned coal ash deposits were greater than those of the active deposits. Moreover, the empirical association of V s profiles from active and abandoned coal ash deposits in India, based on the present study and reported literature, yields a piecewise linear relationship between shear wave velocity and depth. • Shear wave velocity (V s ) values from MASW for three coal ash ponds in India. • Box and whisker plots for inter and intra-site variations in V s profiles. • Comprehensive data on the variation of V s vs. z for all Indian coal ash deposits. • Empirical association between in-situ average shear wave velocity, V s,a vs. z for Indian ashes.

Mid to late Holocene sea-level rise and precipitation variability recorded in the fringe mangroves of the Caribbean coast of Panama

Throughout the Holocene, two of the most important factors involved in the evolution of tropical coastlines have been fluctuations in sea level and regional climates. The geological record provides insightful realizations of the complex interaction between these two factors, improving our understanding of the evolution of littoral zones. Here we present the sedimentary record of a mangrove swamp located in Punta Galeta, Caribbean coast of Panama. Through the conjunction of geochemical and biological sedimentary indicators, we reconstruct environmental dynamics of the area for the last ~5200 years. Between ~5200 and ~1800 cal yr B.P., the progressive dominance of carbonates and a decrease of mangrove pollen indicate increasing marine influence in the area, probably facilitated by a progressively drier climate. Between 3100 and 1800 cal yr B.P., the embayment was flooded by marine water resulting in a landward migration of mangroves. From ~1800 cal yr B.P. to present, the pollen and organic matter records indicate that mangrove vegetation belt recovered, contributing a large proportion of organic matter to the sediment and advancing the shoreline seaward. The maturation of the mangrove forest has resulted in a progradation process that offsets between 4 and 5 m of sea level rise occurred through the last ~5000 years. This process was facilitated by the progressive decrease in rates of sea level rise and by increasing sedimentation rates resulting from a higher accumulation of organic matter from the more vigorous vegetation and more terrigenic input associated with higher regional precipitation. The record of Punta Galeta demonstrates that the evolution of fringe mangroves throughout the Holocene has been mostly driven by sea level rise, which effects are potentially offset by erosion during times of high precipitation. Thus, across the Caribbean coast, precipitation regimes have played a pivotal role at defining the structure and function of mangrove communities. • Sea level rise has dominated coastal dynamics in Punta Galeta through the Holocene. • Mangroves have played a central role at counteracting sea level rise. • Precipitation variability has modulated the effect of sea level rise on the regional coastline.

Postglacial relative sea level change in Norway

We present the first comprehensive postglacial relative sea-level (RSL) database for the Norwegian coast from Oslo to the Kola Peninsula. The database spans the last 20 kyrs and is composed of 413 index points and 610 limiting data points derived from raised beaches, archeological data, glaciomarine terraces, and sedimentary indicators from isolation basins, salt marshes, and peat bogs. The data are quality controlled, assigned standardized indicative meanings, and recalibrated to current standards. We use an ensemble of Bayesian statistical models, trained on sea-level index points and weighted by their fit to both index and sea-level limiting points, to assess the spatiotemporal patterns of Norwegian RSL change. Continuous RSL fall driven by isostatic rebound in response to Eurasian ice sheet collapse dominates the RSL signal at every inland location in Norway. A first transgression (episode of RSL rise), which occurred in southwest Norway during the Younger Dryas (14–11.7 ka), increased RSL by as much as 15 m in some locations. A second transgression, named the Tapes transgression, occurred during the early-mid Holocene between 10 and 5.5 ka. The spatiotemporal model ensemble constrains the timing, amplitude, and spatial distribution of the Younger Dryas and Tapes transgressions. Based on our modeling results, we speculate that the Tapes Transgression was the result of global mean sea level rise temporarily outpacing isostasy-driven RSL fall, while the Younger Dryas Transgression was likely the result of local ice sheet readvance combined with low viscosity asthenosphere and weak lithosphere in the region. We also describe the effects of peripheral bulge migration on Norwegian RSL, which caused increased RSL in the early Holocene and a delayed Tapes transgression. We show that postglacial RSL data in Norway contain complex spatiotemporal patterns of nearfield RSL change that can best be estimated by combining a high-quality data compilation with glacial isostatic adjustment modeling via a robust statistical model.

An Assessment of Alternate Fertilizer Potential of Glauconite Deposits in India using Simple Beneficiation Methods

Abstract This study presents an assessment of alternate fertilizer potential of glauconite deposits in India with precise stratigraphy, dimension of the deposit, and its K2O contents for understanding their alternate potash fertilizer potential. Further, it provides simple beneficiation methods to separate glauconite from the rest of the sediments. Many of the glauconite deposits, particularly those of Precambrian age, are considerably thick and are laterally extensive. Although the content of K2O is low in the bulk rock, it is moderate to high in the glauconites. The glauconite content of the original deposits is low, mostly in the range of 10 to 20 wt%. Inexpensive and simple methods such as sieving and electromagnetic separation enhance the glauconite content up to 57 wt% in selected samples. This study is crucial for planning alternatives of conventional potash fertilizer, which are expected to be exhausted in the near future.

A Clinical Study on Green Banking Initiatives in India With Special Reference to Select Public Sector Banks

Following the global footsteps, the COVID 19 pandemic encouraged the adoption of e- banking practices, as a part of green initiatives. In this perspective, green banking practices have become very significant in public and private sector banks. Public sector banks account for roughly 70 per cent of the total deposits in India. In this article, an attempt has been made to study the present scenario of green banking in India with special reference to select public sector banks. Green banking along with active participation of all the related stakeholders could help in reviving the pandemic-stricken Indian economy, keeping the sustainability goals intact.

Palaeolithic assemblages associated with Youngest Toba Tuff deposits from the upper Gundlakamma River basin, Andhra Pradesh, India

Abstract Archaeological and geological remains associated with the Youngest Toba Tuff (YTT) deposits in India are seen as significant proxies for reconstructing (1) initial modern human colonization of India and (2) possible climatic impacts of the Toba super-eruption of 74 ka on the Indian climate and hominin behaviour. In order to gain further insights into the environmental impacts and behavioural adaptations of human populations in India before and after the Toba eruption, we investigated archaeological horizons associated with the Toba ash beds along the Gundlakamma basin in Prakasam District, Andhra Pradesh, India. Here, lithic artefacts were identified below and above the YTT deposits. The YTT deposits in the Gundlakamma River basin have a maximum thickness of 50 cm, comparatively thinner than those at the better investigated valleys of the adjacent Jurreru and Sagileru in Andhra Pradesh and the Son, Madhya Pradesh, India. Our surveys indicate that the Palaeolithic assemblages associated with YTT deposits from the Gundlakamma River basin can provide significant insights into the issues and debates surrounding the Toba archaeology.

Experimental Investigations on Black Cotton Soil Stabilized with Sand and Cement

Abstract: Has our Lands getting increasing of population and the reduction of available land, more and more construction of building sand other civil engineering structures has to be carried out on weak or soft soil. Owing to such soil of poor shear strength and high swelling & shrinkage, a great diversity of ground improvement techniques such as soil stabilization and reinforcement are employed to improve mechanical behavior ofsoil, thereby enhancing the reliability of construction. Black cotton soil is one of the major soil with this we are going to improve the soil by using sand and cement in deposits of India. The disappointments of asphalt in from of hurl dejection splitting and unevenness are brought about by the occasional dampness variety in subgrade soil. So, in this we using the various type of tests like plastic limit, liquid limit, California bearing ratio test, freewell index and specific gravity.Instead of cutting out and replacing the unstable soil,soil adjustment isthe only alternative asitsaveslot of time and ofmoneytoo.Theexhibithigh swelling and shrinking when exposed to changes in moisture content and hence have been found to be most troublesome from engineering considerations. Keyword: Black cotton soil, stabilization, CBR, sand and cement, sub- grade, Montmorinolite kaolinite, hydrated cations, Liquid Limit, Plastic Limit, Free swell index, Specific gravity.

Hierarchical fuzzy-AHP-based multi-criteria decision making approach for selection of underground metal mining method

In the last few decades, many underground mining methods were proposed for extractions of ores. The decision-making for selecting the most suitable mining method for a typical ore depost depnds on various intrinsic and extrinsic factors (intrinsic – dip, shape, thickness, depth, grade distribution, RMR (rock mass rating) and RSS (rock substance strength) of ore, hanging wall, footwall, and extrinsic – recovery, dilution, safety, productivity, flexibility, capital). The present study aims to develop a hierarchical Fuzzy-AHP (FAHP) model for choosing the most suitable underground mining method for an ore deposit. The structure of the proposed hierarchical FAHP model consists of five levels. The level-1 of the hierarchy defines two variables (intrinsic factors and extrinsic factors). These are further classified into quantitative or qualitative nature of variable (listed in level-2). The criteria, sub-criteria, and mining method variables are listed respectively in Level 3, Level 4, and Level 5. For each level of the hierarchy, a fuzzy pair-wise comparison matrices are developed using the corresponding levels’ listed variables. These matrices at each level are subsequently used to determine the local and global weights of each variable. The global weights are used for prioritizing the different mining methods. The proposed hierarchical FAHP model was validated by considering the field data of two different ore deposits in India. The results showed that the most appropriate mining method predicted from the decision-making model and the adopted mining method for extracting the ore deposit are same in two case studied mines.

Sedimentological responses to initial continental collision: triggering of sand injection and onset of mass movement in a syn-collisional trench basin, Saga, southern Tibet

A continuous Late Cretaceous–Paleocene sedimentary succession within the India–Asia collision suture zone in Xigaze, Tibet contains a c . 80 m thick sand injection complex immediately overlain by a c . 60 m thick mass transport deposit (MTD; the first of several) with the first evidence of Asian provenance, immediately followed by a c. 61 Ma tuff. The youngest in situ strata with unequivocal Indian provenance are probably the source beds of the sand intrusions, separated from the first MTD by c . 50 m of pelagic deposits that potentially represent an interval of several million years; the collision could thus have occurred at any time within this interval. However, the uppermost limit of the sand intrusions closely coinciding with the MTD suggests that they occurred penecontemporaneously, possibly associated with the initial continental collision. This may provide an additional constraint of initial collision onset at c . 61 Ma. The co-occurrence of MTDs and sand injections are possibly good sedimentary indicators of the onset of continental collision and are characteristic of syn-collisional trench basins. Because neither the youngest Indian nor the oldest Asian provenance sediments are in their original stratigraphic position, this study shows that detailed sedimentological work combined with provenance study can better constrain the timing of continental collision.