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Information on Symposia per Science Theme





Theme No.

Theme Title

Number of Symposia proposed

Symposia Title

Symposia Conveners

Biographical sketch of the Conveners

Keywords

Abstract

14

Emerging Trends in Exploration for Deep and Concealed Resources


D. S. Jeere dsjeere@gmail.com (India)


Dinesh Gupta dineshguptagsi@yahoo.co.in

(India)


Richard Blewett Richard.Blewett@ga.gov.au (Australia)

8

Regolith geology and concealed mineral deposits

Ignacio González-Álvarez

Ignacio.Gonzalez-Alvarez@csiro.au

(Australia)



Regolith units are the result of in situ and/or transported material, which has been affected by weathering processes. Understanding genetic aspects of regolith could help in mineral exploration by providing broader targets or obstruct exploration by concealing the bed rock targets, preventing easy sampling, concealing structures, lithological units etc. Genetic models of regolith mainly include climatic, geomorphological, pedological, tectonic domains and the classification of mapping units are mostly dependent on the terrain, scale and information extractability. In general, basic information like in-situ versus transported regolith, understanding provenance, effect of paleo to modern drainages are the key elements needed to the explorer. The various mapping techniques may include remote sensing, interpretation of geophysical data sets, geochemical sampling, spectrometric studies and ground validation etc. Several approaches are developed to map them. Currently, mineral exploration has concentrated on concealed deposits in regolith-covered terrains. Characterization of cover material as residual, transported or as complex nature by taking the aid from spectral studies, heavy minerals, geochemistry, age dating of detrital material etc. are the emerging techniques.

Genetic classification schemes for regolith, methodologies of mapping at regional and local scales, importance of a specific genetic class of regolith for a targeting particular mineral deposit, geochemical and geomorphological nature of regolith, methodologies of characterization of cover material, successful application of numerous techniques, effective use of varieties of geoscientific data sets and other related issues are the key subjects under this symposium.

Application of aerogeophysical Data Sets for Target Delineation through Basement Mapping/ Predictive Geological Mapping of Potentially Covered Terrains

B. K. Sahu,

sahubk2010@gmail.com

(India)



A geological map of a largely covered terrain prepared using potential field data sets and outcropping geology is a predictive geological map. Regional potential field datasets are increasingly used to create the basement or predictive geological maps of regions with little or no outcropping areas. Evaluation of constrained density and magnetic susceptibility models with measured potential field data through modelling clubbed with known outcropping geological parameters plays a powerful tool to create the predictive geological maps of the covered terrains. The airborne magnetic data can through light on granitoid - gabbroid domains consisting of multiple generations of individual intrusions may give insights on the broad geodynamic models.

Creation of the predictive geological maps involving identification of the near-surface and deeper responses and classifying the remaining responses according to their possible sources, integrated analysis of multiple data types, i.e. magnetics, gravity, radiometrics, conductivity, outcropping geology etc., to produce a more reliable model of the covered terrain or subsurface geology are the subjects under this category. The advancements and success stories related to delineation of mineral potential areas of covered regions, data acquisition, processing, spatial analysis, application of filters by airborne geophysical methodologies viz., magnetics, time domain magneto-gradiometry, gravity gradiometry, airborne electromagnetic etc., are the key discussion elements of the symposium.

Mineral System Approach for Enhancing Mineral Deposit Discovery Rate in the Potentially Covered Terrain

M. N Praveen,

praveenmn74@gmail.com

(India)



Deeply weathered and regolith covered terrains may coincide with the tectonic domains and hence mineral system approach can help the explorer in targeting the mineralization below cover. Mineral exploration in covered terrain is challenging, requiring the development of new technical tools and approaches. Mineral system features include the geological setting, fluid drivers, fluid and metal sources, fluid pathways, depositional traps and post depositional modifications. All of these components link to geodynamic processes and the tectonic system. Transported cover is an obstacle to mineral exploration as it masks the detect Mineral System Approach for reversing the decline in mineral deposit discovery in the covered terrain table signature of buried mineral systems and dispersion of indicator elements to the surface. Mineral system gives an opportunity to generate prospectivity maps of potentially covered regions to enhance the rate of mineral deposit discovery.

Translating mineral system elements into mappable criteria, delineation of presence of a particular mineral system in covered regions, new advancements in mineral system studies, various rankings for varieties mineral systems, identification of critical elements, working on greenfield regions for mineral potentiality etc., are the mine issues for this symposium.

Advances in Geophysical Approaches for Tracing Concealed and Deep Structures and Materials

M. K. Mukherjee, mrinal_km67@yahoo.co.in

(India)



Geophysical techniques, such as seismic surveys, gravity modelling, magnetic data, deep electrical resistivity surveys, varieties of magneto-telluric methods etc., are all well-established tools for delineating shallow to deeper geological materials and structures of both covered and exposed terrains with variable degrees. The algorithms developed for handling observed gravity data by many geoscientists is growing to derive the structure of upper crust, sedimentary basin or both. Seismic reflection surveys generate the detailed images of the subsurface allowing to delineate structure and stratigraphy.

Highlights on delineation of fault systems and other crustal scale structures by using the data sets of seismic survey, gravity, magnetics, deep electrical soundings etc., and magneto-telluric models for deep conductive zones. Mapping of potential structural conduits, fault splay systems using remote sensing data, structural traps, structurally permeable zones of mineralizing fluids etc., shall fall in this symposium.

Ground Geophysical Methods of Gravity, Magnetic, Electrical, Electromagnetic to Bring Out Concealed Fertile Bodies

G. Karunakar

karunakar65@yahoo.com

(India)



Gravitational and geomagnetic measurements are useful to find underground targets that have significant differences in density and magnetism. Integration of petrophysical and geophysical data sets in the modelling process, such as gravity and magnetic field data, can provide crucial information as to the nature and distribution of density contrasts and magnetic material in the subsurface. In mineral exploration, for covered and partially covered regions, electrical and electromagnetic methods are used at regional to prospect scale for direct detection of electrically anomalous targets, in particular metal sulphide and metal oxide mineralization. Information about the geometry, dimensions and electrical characteristics of the sources of anomalies can be obtained. The magneto-metric methods are effective for sufficiently electrically conductive bodies may be related to the host rocks, to produce a measurable anomaly at deeper depths. Ground penetration radar surveys are for mostly shallow investigations of regolith hosted and placer mineralization in addition to determining the thickness and continuity of subsurface layers and cover materials.


Modelling source geometry, depth of source, responses from different litho-types, fault zones etc., of potentially covered regions by magnetic, gravity, electrical, electromagnetic are the main foci under this symposium.

Geochemical Techniques of Tracing Distal Footprints of Concealed Mineral Deposits

David Cohen,

d.cohen@unsw.edu.au

(Australia)



As mineral deposit discovery rates decline, increased attention is being focused on geochemical exploration methods for application in covered terrains. Basement geochemical signatures are masked within the cover due to the geochemical and other intricacies of the regolith. Hence, majority of ore deposits those are hidden by burial and deep weathering are yet to be discovered. In a specific geo-environment when many geophysical techniques have limited application, geochemical methods can be used as an efficient tool for mineral exploration particularly, in regolith predominant terrains. Depletion and enrichment of specific elements and their selective ratios in primary haloes of certain mineral deposits have also been used for vectoring toward ore zones in recent times.

Pathfinder elements, various geochemical sample media, leaching techniques, threshold values, mobile metal ion methodology, vectoring towards ore zones, case studies on discovery of concealed deposits by geochemical techniques etc., are the elements considered in this symposium. Groundwater sampling techniques, analytical and interpretation techniques, trace metals and metalloid concentrations, isotopic applications, metal saturation, ion exchange, mobility in various environments, threshold values of indicator metals, buried mineral deposit discovery etc., and are also part of this symposium.

Recent Advances in Detection of Concealed Mineral Deposits by Integration Geoscience

M. N. Mishra,

mnmishra4@yahoo.co.in

(India)


R. Balaji,

(India)



Geological, geophysical, geochemical and geochronological constraints such as gravity & magnetic records, aerogeophysical data sets, magneto-telluric, seismic interpretations, geochemical data, drill hole information with an understanding on tectono-magmatic history and mineral system by integration geoscience approach significantly reduces the risk of mineral exploration, mostly for the largely covered areas. In a geospatial environment, various layers with different geo-scientific information may be overlain and analyzed as an integrated dataset for prioritization of detailed exploration.

Construction of litho-structural maps using field observations integrated with airborne and ground geophysical data, satellite data, alteration maps, geochemical data sets etc., by various statistical modelling for various deposit styles, prospectivity analysis by index overlay, fuzzy logic etc., mostly to the cover dominant terrain are the main subjects encompass in this symposium.

Developments in Targeting Concealed and Deep Seated Uranium –REE Mineralization

A. K. Chaturvedi anandlko57@gmail.com

(India)



With growing demand of sustainable clean Energy resources worldwide, nuclear energy has a very important role to play. Bulk of the world uranium resources are accounted for by the Proterozoic unconformity related deposits, Middle Proterozoic Iron Oxide Breccia complex and Phanerozoic sandstone type uranium deposits.

Last decade witnessed significant advancement in understanding mineral deposits in relationship to internal and external processes of the Earth, exploration techniques, instrumentation, data processing and interpretation techniques. In particular, Airborne Electromagnetic methods (AEM) proved to be very successful in assisting uranium Exploration. AEM has proven to be particularly useful in places such as the central parts of Africa, South America and Australia, where approximately 80% of the landscape is covered by regolith and sedimentary basins.

Integration of multi parametric geospatial datasets acquired over different geological terrains have been studied to delineate favorable locales for uranium exploration. These data sets include satellite imagery, aeromagnetic, aero-radiometric, airborne time domain electromagnetic, geological and structural data layers. Thematic layers of conductive horizons, faults and fracture zones, alteration zones, radio elemental rich zones, lithological, geochemical are extracted from geospatial data sets. GIS tools facilitate data transformation, visualization, analysis, modelling and spatial decision support required for integrating exploration datasets in generating mineral potential maps and in defining suitable zones for detailed uranium exploration.

In addition to applying suitable geoscience applications of discovering Uranium mineralization as discussed above, the exploration of strategically important Rare Metals and Rare Earth Elements in beach sand placers, concealed alkaline suite of rocks and carbonatites in various geological environments are the main subjects under this symposium. Different Geophysical techniques, geochemistry etc., which are very successfully used in tracing such concealed deposits are also part of this symposium.