Vysetti Balaram

Handheld Laser-Induced Breakdown Spectrometry (hLIBS) is capable of simultaneous multi-element analysis of a variety of geological materials such as rocks, minerals, ores, soils, sediments, and water. This is a transformative analytical technology that is currently revolutionizing the field of critical mineral exploration studies. By providing real-time, in situ elemental analysis in the field with detection and quantitative determination capabilities for light elements (such as Li, Be, and B), where other handheld techniques like portable XRF struggle, hLIBS empowers geologists to make faster and more informed decisions in the field, significantly accelerating the exploration process from prospecting to target delineation. Several important practical examples of the exploration of critical metals, such as lithium, rare earth elements, copper, cobalt, and titanium, are presented. In particular, the detection capability of indicator minerals and pathfinding elements by hLIBS is extremely valuable for critical mineral exploration studies. Similar instruments have also been successfully used in recent years in challenging environments like space and deep-sea environments. The capability of remotely operated miniature LIBS in hostile environments such as the deep sea, Moon, and Mars is discussed with examples. LIBS has become a key technology for in situ chemical analysis in both space and deep-sea exploration because of its ability to identify elemental composition rapidly and without physical contact.

There is large variations in diverse water samples due to time interval between sample collection and analysis in the presence of fluoride and humic substances in hot arid regions.

Lithium is a critical metal required for several green technology applications such as electric and hybrid vehicles, energy storage systems, lubricants, polymers, pharmaceuticals, and the preparation of a lot of other industrial chemicals, and its demand is rapidly increasing worldwide. The three most important resources of lithium are pegmatite deposits, salt brine deposits, and sedimentary deposits, and a minor component of unconventional lithium deposits such as geothermal waste, lithium in borate deposits, lithium-enriched coal deposits, lithium-rich industrial wastes such as red mud, acid mine drainage, and recycling. Several studies indicated that marine mineral deposits such as ferromanganese nodules and ferromanganese crusts also contain significant lithium concentrations, and can provide a new solution to the demand for lithium. Currently, sedimentary deposits both on the land and deep oceans are receiving increasing attention, due to their large size and their potential for future lithium resources. While land sedimentary deposits showed a high value of lithium up to 7250 μg/g, the marine sedimentary deposits recorded a high of 781 µg/g. Here, an attempt is made to provide a summary of global lithium sedimentary deposits and their potential for large-scale and long-term production of lithium. In addition to the descriptions of the importance of mineral deposits of lithium, a brief outline of different types of lithium deposits such as brine deposits including continental and geothermal, petroleum brine, pegmatites, and related magmatic deposits are also presented. Similarly, exploration studies based on geological, geophysical, mineralogical, geochemical, and remote sensing techniques in sedimentary basins are also briefly discussed. This cumulative information on sedimentary lithium deposits can trigger many future studies in unexplored and underexplored terrains around the world.

In this study, we report Scanning Electron Microscopy (SEM) images of quartz grains in the Acapulco beach, Mexican Pacific. The morphology of quartz grains is angular, sub-angular, sub-rounded, rounded, and well-rounded. The variations in the morphology of quartz grains are indicating both nearby and distance sources. The rounded and well-rounded grains support for a long transport distance and a distal source. Microtextures of mechanical and chemical origins are identified in quartz grains. The mechanical features include, bulbous edges (ble), elongated depression (ed), parallel striations, crater, meandering ridges (mr), arcuate steps, conchoidal fractures (cf), v-shaped marks (v-s), and broken grain. These mechanical features indicate the combination of fluvial, aeolian, and subaqueous environments. The conchoidal fractures are characteristic of crystalline rocks. Arcuate steps and meandering ridges are indicating a high wave energy. The striations on grain surfaces are due to collision between two grains, probably during an aeolian transport. The chemical features include adhered particles (ap), solution pit (sp), silica globule, crystal overgrowth (crg), precipitation, and trapped diatoms. The solution pits and precipitation are indicating the diagenetic processes in a silica saturated coastal environment. A few grains are associated with both mechanical and chemical features, suggesting a dual environment, probably littoral and marine. Trapped diatoms identified in quartz grains are Cocconeis guttata and coccolith.

Application of differential technique is based on the comparison of the fluorescence of the standard with a sample of similar but unknown concentration on the same sample weight basis, by the use of H₃PO₄–NH₄H₂PO₄ as a fluorescence-enhancing reagent.

The use of analytical techniques is important and critical in all areas related to REE, such as basic fundamental research, exploration, mining, extraction, and metallurgical activities at different stages by different industries. At every stage of these activities, rock, ore, minerals, and other related materials have to be analyzed for their REE contents in terms of elemental, isotopic, and mineralogical concentrations using different analytical techniques. Spectacular developments have taken place in the area of analytical instrumentation during the last four decades, with some of them having shrunk in size and become handheld. Among laboratory-based techniques, F-AAS, GF-AAS, ICP-OES, and MP-AES have become very popular. Because of high sensitivity, fewer interference effects, and ease of use, ICP-MS techniques, such as quadrupole ICP-MS, ICP-MS/MS, ICP-TOF-MS, MH-ICP-MS, HR-ICP-MS, and MC-ICP-MS, with both solution nebulization as well as direct solid analysis using laser ablation sample introduction methods, have become more popular for REE analysis. For direct analysis of solids, INAA, XRF, and LIBS techniques, as well as LA-based ICP-MS techniques, are being extensively utilized. The LIBS technique in particular requires little to no sample preparation. TIMS, SIMS, and SHRIMP techniques are being used for isotopic as well as dating REE depots. Portable analytical techniques, such as pXRF, pLIBS, and Raman spectrometers are able to perform in situ analysis even in the field, helping to make fast decisions during exploration studies. At present, hyperspectral remote sensing techniques including handheld, drone, and satellite-based techniques have become very popular in REE exploration studies because of their ability to cover larger areas in a limited time and, thus, became very cost-effective. Deployment of microanalytical devices/sensors mounted in remotely operated vehicles (ROV) is being successfully utilized in detecting REE-rich deposits in the deep oceans. Providing updated in-depth information on all these important aspects with suitable examples, especially from the point of view of REE research studies is the focal point of this review article.