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Abstract
The Bastar craton (Chattisgarh State) is rich in mineral deposits including diamondiferous kimberlite rocks. The kimberlite occurrences have been reported from different parts of the bastar craton including Mainpur-Deobhog Area (MDA) in Raipur district. As a rule, the kimberlites occur in clusters and hence, arises the need for strategic exploration guide for the kimberlites. Integration of available background information (viz. geology, tectonics, geochronology, rock chemistry etc.) in GIS environment leads to development of Kimberlite Exploration Geographic Information System (KEGIS). The KEGIS paves the way for further kimberlite exploration programme.
Introduction
The exploration of Kimberlite has an inherent meaning - "exploration for diamond". The Kimberlite exploration involves very risk, which when successful, returns very high rewards. One of the major guideline for Kimberlite exploration is sound understanding of tectonic control on evolution, emplacement and preservation of kimberlite. The fundamental requirement for diamondiferous Kimberlite occurrence is a persistently low geothermal gradient with little thermal erosion as the plume events may destroy the diamond potential of post plume Kimberlite magmatism. The formation and ascent of kimberlite is speculative, however, lithospheric extension is considered to be the main cause for trigger of Kimberlite magmatism. As a rule (Cliford 1966), the kimberlite is found in clusters, fields and provinces exclusive within thick Archaean cratons and immediately adjacent to Proterozoic mobile belt. An especially favourable environment for preservation of kimberlite diatrems is a craton covered by relatively undeformed sedimentary rocks. The exhumation and/or deep erosion of craton leaves behind the root zones of kimberlite diatrems and hypabyssal feeder dykes. Often, kimberlite occurrences indicate distinct alignment with local fault and dyke systems and are related to frequently reactivated regional lineaments (White et al 1995; Smirnov 1993). Any successful prognostic map of kimberlite country takes into account, available regional geological and geophysical maps, remotely sensed data products, indicator mineral occurrences, alkaline mafic rock occurrences, presence of high permeability zones, characteristics of craton and mobile belts, presence of sedimentary cover on craton etc.
Exploration guide for kimberlite
The first and foremost exploration guide for Kimberlite is the known occurrence of Kimberlite. Once a Kimberlite occurrence is located in any area, the next essential factor for exploration becomes the establishment of regional and local structural control on the emplacement of kimberlite. This task is best achieved through remote sensing techniques supplemented with ancillary data. In Mainpur-Deobhog Area (MDA, Raipur district, Chattisgarh, Fig. 1) there are four known occurrences of kimberlite. Thus, search for new kimberlite occurrence in this area is practically reduced to application of remote sensing technique in understanding the tectonic setting of kimberlite emplacement. The exploration strategy for kimberlite is best achieved through development of GIS with available background information.
Fig. 1. Location map of Mainpur-Deobhog Area
Moreover, the search for kimberlite involves several other factors. The kimberlite occurrences are revealed by observation such as, higher magnetic-gravity values, juxtaposition of cool cratonic mass - mobile belt -intracratonic basin, anomalous enrichment of Nb-Ni-Cr-Ce-Mg-Ba in weathered and/or soil horizon, exceptionally rich vegetation in an otherwise vegetation poor country etc. The identified exploration guides for kimberlite of MDA in the background of global exploration guide is presented in Table-1. The best correlation of topographic tectonic, geochemical and geophysical data is achieved by development of KEGIS.
Development of KEGIS
"The kimberlite occurs in clusters"- it is the guideline for development of Kimberlite Exploration Geographic Information System (KEGIS) in MDA. Accordingly, an area including the four known kimberlite occurrences and bounded by latitude N 20.00 to 20.30 and longitude E 82.00 to 82.30 is selected for rigorous. The selected window covers an area of approx. 2100 sq. km and falls in SOI toposheet nos. 64 L /3,4,7 & 8. The objective behind KEGIS is developing a geological information system for kimberlite exploration in MDA. KEGIS permits available data to be manipulated and displayed quickly. The results may be displayed in several formats and can be stored for repetitive application. The study takes into account the topographic, drainage, lithologic, tectonic, geochemical and other important data used for kimberlite exploration. These data are incorporated into the digital database for further manipulation and development of KEGIS. The digital data used for study are IRS-1C/1D products. The aerial photographs are used for collection of additional information for data input. The methodology adopted for development of KEGIS is presented in Fig 2.
Fig. 2: Strategy for KEGIS development
Database for KEGIS
The Satellite view of the Mainpur-Deobhog area is shown in Fig. 3. The image clearly indicates ideal location for the occurrence of kimberlites. The basement granitic rocks are hosting platformal Khariar sediments with boundary between two as Sondur lineament. The circular and/or oval geomorphic depressions are also distinct on the image. The Eastern Ghat Mobile Belt (EGMB) is welded to the central massif through a major thrust cum shear zone. The geologic map is presented in Fig. 4. The lineament density map and associated rose diagram are shown in Fig. 5. The database building for any GIS project involves demarcation of spatial extent of selected area in an appropriate co-ordinate system. The same co-ordinate system is used for all data inputs. The lines, polygons, control points etc. in the input are digitized to obtained the same co-ordinate system such that the spatial components overlap correctly in the map overlays. The UTM co-ordinate system is used for data input in the present study. The area co-ordinates (in metric system) are the lower left corner (x = 220234.91, y = 595928.39) and upper right corner (x = 2276651.08, y = 664999.36)
Fig.3 IRS 1D image view of the area of investigation.
The lithologic, tectonic, drainage maps and geochemical data of the selected window are digitized and used as database for KEGIS. The software used for development of KEGIS is ILWIS-2.1, developed by ITC, The Netherlands. The software gives highest flexibility and combines raster and vector based GIS, as some analytical technique can be best performed in vector mode while others in raster mode. The information is extracted from prepared thematic maps and finally six important 'attribute input data' are identified for further operation. The attribute input data are subjected to Fuzzy Logic Operation that is based on membership values given as attribute value, ranging between 0 & 1. The contact between Proterozoics and Archaeans and, the area occupied by coarse-grained granite are selected from the geological map and buffered to produce a proximity map. Similarly proximity map is derived from the structural map indicating distance of influence zone from the normal fault, which is used as an evidence for proximity to heat source. Based on distance from the center, the coarse grained granite is separated into 10 different zones and each zone is buffered. The geochemical data for elements Ni, Co and Cr, supposed to be important indicators for rocks of the kimerlite clan, is classified on a scale designed to accentuate and enhance those areas with anomalous high value of Ni (650 to 2000 ppm), Cr (400 to >1000 ppm), Co (40 to 200 ppm). Choosing anomalous drainage patterns enhances the drainage map and allows preparing the derivative map. The attribute data and the assumptions are combined together in the base buffer zone to be used in KEGIS.
Fig. 4. Geologic Map of Mainpur-Deobhog area
Fuzzy logical operation
All the available information that provides evidence for kimberite exploration is combined together by means of fuzzy logical operation. The fuzzy logical operation is used for the development of KEGIS as fuzzy logic allows for more flexible combinations for weighted information and can be readily implemented with a GIS modeling language. All these are based on subjective empirical models linked to weights or fuzzy memberships values assigned subjectively using knowledge of the process involved to estimate the relative importance of the input map. This is carried out in stages, with the ultimate product being a predictive map indicating the relative favourability of kimberlite emplacement. The combination processes involves weighing and fusion of evidence carried out in a number of different ways.
Fuzzy membership functions are subjectively assigned weight to each type of evidences, thereby controlling the relative weighting of the data. Alternatively, the evidences could have been weighted statistically, using the observed association of the evidence map with known occurrences of kimberlite pipes. Several operations can be employed using the evidence maps with combination of fuzzy membership value together. For the development of KEGIS, fuzzy algebraic product, fuzzy algebraic sum and, fuzzy gamma operations are deployed.
Fuzzy algebraic product
With combination of all six evidence maps and the employed fuzzy algebraic product, the combined membership function is defined as
Where µ = Fuzzy membership value for ith map
And, i = 1 to 6 (evidence maps are combined)
The combined fuzzy membership values tend to be very small with this operator, due to effect of multiplying several numbers less than 1. The output is always smaller than or equal to the smallest contributing membership value and is therefore, "decreasive".
Fuzzy algebraic sum
This operator is complementary to the algebraic product, defined as.
Where µ = Fuzzy membership value for ith map
And, i = 1 to 6 (evidence maps are combined)
The result is always larger (or equal to the largest) contributing fuzzy membership value. The effect is therefore, "increasive".
Two pieces of that both evidences favouring a hypothesis are reinforced into one another and the combined evidences are more supportive than either piece of evidence taken individually. In case of present investigation fuzzy algebraic sum of (0.95, 0.1) is 1(1-0.95) X (1-0.1) that is equal to 1.0 (FMV).
The increasive effect of combining several favourable pieces of evidences is automatically limited by the maximum value 1.0, which can never be exceeded. Note that, whereas the fuzzy algebraic product is an algebraic product, the fuzzy algebraic sum is not an algebraic summation.
Gamma operation (Gamma = 0.95)
Fuzzy algebraic sum and fuzzy algebraic product were combined together by means of Gamma operation. This is defined in terms of
Combination = (Fuzzy algebraic sum) x ? (Fuzzy algebraic product) (1- ?)
Where ? is parameter chosen in the range (0,1)
When ? is 1, the combination is same as the fuzzy algebraic sum and when ? is 0, the combination is equal to the fuzzy algebraic product. Judicious choice of g produce output values that ensure a flexible compromise between the "increasive" tendencies of the fuzzy algebraic sum and the "decresive" effects of fuzzy algebraic product. The data integration and combination of Fuzzy operation results obtained during KEGIS are used in development of strategy for Kimberlite exploration.
Target area for kimberlite exploration
The prioritization of smaller potential segments for kimberlite exploration takes into account the GIS result, permutation and combination of different exploration data and extensive field database. Through, the kimberlite occurs in clusters, in a given geologic environment the various kimberlite clusters may be separated in space and time. The concentration of diamond and other heavy minerals at the suitable placer locations provide indication for intensity of kimberlite occurrences in any area. The occurrence of diamonds at Sinapali (adjacent to MDA but lying in the state of Orissa and, a trading center for diamonds and other minerals) in placer invariably points towards possible large number of primary sources, located upstream areas falling within MDA. One of the major hindrances in identification of kimberlite in MDA is its small dimension and level of erosion since emplacement. The kimberlite pipes, in general, occur with negative topographic expression and are expected to be picked up in low attitude, closely spaced (200 m X 200 m or even less) aeromagnetic data. Since, on legal ground these data are not available to users, identification of target area for kimberlite exploration remains vague in a sense.
The result of KEGIS yields a fuzzy gamma, which is finally classified on the basis of the histogram of fuzzy membership value. The five probability classes are identified in which fuzzy membership value less than 0.63 indicate low possibility of kimberlite occurrence, where as fuzzy membership value in 0.81 to 0.95 range indicates very high possibility of kimberlite occurrence.
The identified potential zone for kimberlite exploration through KEGIS has limitations. The technique is primarily centered on known kimberlite occurrences and is based on averaging of all observed factors. However, based on real world field data and other exploration guides, priority zones for kimberlite targeting are identified.
Acknowledgements
MSK thanks the DGM, Govt. of M. P. for necessary permission and the IIRS, Dehra Dun for laboratory support.
Suggested readings 
Fig. 5a Lineament intersection density map of MDA
Note the High lineament density girdles that are also favourable sites for kimberlite occurrences.
Fig. 5b Rose diagramme for lineaments of MDA.
The N-S trends are dominated in the Eastern Ghat rocks, the NW-SE trends are prominent in Basement granitic terrain while the Khariar sediments are characterized by NE-SW trending lineaments.
Development of kimberlite exploration Geographic Information System
Mohan Singh Khatediya* and Pramod. K. Verma
School of Studies in Geology, Vikram University
Ujjain-456010, India
Tel. 91-0734-511118, Fax 91-0734-514276
drpkverma@rediffmail.com
*Department of Geology & Mines, Government of Madhya Pradesh, Bhopal
Mohan Singh Khatediya* and Pramod. K. Verma
School of Studies in Geology, Vikram University
Ujjain-456010, India
Tel. 91-0734-511118, Fax 91-0734-514276
drpkverma@rediffmail.com
*Department of Geology & Mines, Government of Madhya Pradesh, Bhopal
Abstract
The Bastar craton (Chattisgarh State) is rich in mineral deposits including diamondiferous kimberlite rocks. The kimberlite occurrences have been reported from different parts of the bastar craton including Mainpur-Deobhog Area (MDA) in Raipur district. As a rule, the kimberlites occur in clusters and hence, arises the need for strategic exploration guide for the kimberlites. Integration of available background information (viz. geology, tectonics, geochronology, rock chemistry etc.) in GIS environment leads to development of Kimberlite Exploration Geographic Information System (KEGIS). The KEGIS paves the way for further kimberlite exploration programme.
Introduction
The exploration of Kimberlite has an inherent meaning - "exploration for diamond". The Kimberlite exploration involves very risk, which when successful, returns very high rewards. One of the major guideline for Kimberlite exploration is sound understanding of tectonic control on evolution, emplacement and preservation of kimberlite. The fundamental requirement for diamondiferous Kimberlite occurrence is a persistently low geothermal gradient with little thermal erosion as the plume events may destroy the diamond potential of post plume Kimberlite magmatism. The formation and ascent of kimberlite is speculative, however, lithospheric extension is considered to be the main cause for trigger of Kimberlite magmatism. As a rule (Cliford 1966), the kimberlite is found in clusters, fields and provinces exclusive within thick Archaean cratons and immediately adjacent to Proterozoic mobile belt. An especially favourable environment for preservation of kimberlite diatrems is a craton covered by relatively undeformed sedimentary rocks. The exhumation and/or deep erosion of craton leaves behind the root zones of kimberlite diatrems and hypabyssal feeder dykes. Often, kimberlite occurrences indicate distinct alignment with local fault and dyke systems and are related to frequently reactivated regional lineaments (White et al 1995; Smirnov 1993). Any successful prognostic map of kimberlite country takes into account, available regional geological and geophysical maps, remotely sensed data products, indicator mineral occurrences, alkaline mafic rock occurrences, presence of high permeability zones, characteristics of craton and mobile belts, presence of sedimentary cover on craton etc.
Exploration guide for kimberlite
The first and foremost exploration guide for Kimberlite is the known occurrence of Kimberlite. Once a Kimberlite occurrence is located in any area, the next essential factor for exploration becomes the establishment of regional and local structural control on the emplacement of kimberlite. This task is best achieved through remote sensing techniques supplemented with ancillary data. In Mainpur-Deobhog Area (MDA, Raipur district, Chattisgarh, Fig. 1) there are four known occurrences of kimberlite. Thus, search for new kimberlite occurrence in this area is practically reduced to application of remote sensing technique in understanding the tectonic setting of kimberlite emplacement. The exploration strategy for kimberlite is best achieved through development of GIS with available background information.
Fig. 1. Location map of Mainpur-Deobhog Area
Moreover, the search for kimberlite involves several other factors. The kimberlite occurrences are revealed by observation such as, higher magnetic-gravity values, juxtaposition of cool cratonic mass - mobile belt -intracratonic basin, anomalous enrichment of Nb-Ni-Cr-Ce-Mg-Ba in weathered and/or soil horizon, exceptionally rich vegetation in an otherwise vegetation poor country etc. The identified exploration guides for kimberlite of MDA in the background of global exploration guide is presented in Table-1. The best correlation of topographic tectonic, geochemical and geophysical data is achieved by development of KEGIS.
Development of KEGIS
"The kimberlite occurs in clusters"- it is the guideline for development of Kimberlite Exploration Geographic Information System (KEGIS) in MDA. Accordingly, an area including the four known kimberlite occurrences and bounded by latitude N 20.00 to 20.30 and longitude E 82.00 to 82.30 is selected for rigorous. The selected window covers an area of approx. 2100 sq. km and falls in SOI toposheet nos. 64 L /3,4,7 & 8. The objective behind KEGIS is developing a geological information system for kimberlite exploration in MDA. KEGIS permits available data to be manipulated and displayed quickly. The results may be displayed in several formats and can be stored for repetitive application. The study takes into account the topographic, drainage, lithologic, tectonic, geochemical and other important data used for kimberlite exploration. These data are incorporated into the digital database for further manipulation and development of KEGIS. The digital data used for study are IRS-1C/1D products. The aerial photographs are used for collection of additional information for data input. The methodology adopted for development of KEGIS is presented in Fig 2.
Fig. 2: Strategy for KEGIS development
Database for KEGIS
The Satellite view of the Mainpur-Deobhog area is shown in Fig. 3. The image clearly indicates ideal location for the occurrence of kimberlites. The basement granitic rocks are hosting platformal Khariar sediments with boundary between two as Sondur lineament. The circular and/or oval geomorphic depressions are also distinct on the image. The Eastern Ghat Mobile Belt (EGMB) is welded to the central massif through a major thrust cum shear zone. The geologic map is presented in Fig. 4. The lineament density map and associated rose diagram are shown in Fig. 5. The database building for any GIS project involves demarcation of spatial extent of selected area in an appropriate co-ordinate system. The same co-ordinate system is used for all data inputs. The lines, polygons, control points etc. in the input are digitized to obtained the same co-ordinate system such that the spatial components overlap correctly in the map overlays. The UTM co-ordinate system is used for data input in the present study. The area co-ordinates (in metric system) are the lower left corner (x = 220234.91, y = 595928.39) and upper right corner (x = 2276651.08, y = 664999.36)
Fig.3 IRS 1D image view of the area of investigation.
|
Exploration guides for Kimberlite
General: Area comes under Bastar craton with abnormally cool keel of lithosphere, Eastern Ghat Orogenic Mobile Belt borders Bastar craton; Archaean rocks of Bastar craton are in contact with the Proterozoic intracratonic Khariar basin; a zone of high magnetic permeability as defined by repeated intrusion of various types of igneous rocks; Morphological depressions are recognised.
Geochronology: Eastern Ghat Mobile Belt (EGMB) is thermo-tectonically reactivated in 1500±2000 Ma and 800±100 Ma; 1000 Ma event in EGMB coincides with the kimberlite orogeny; the Khariar Proterozoic platformal sediments indicate two cycle of sedimentation i.e. 1100-900 Ma and 700-450 Ma. The maximum thickness of sedimentary cover rock is about 1000m. Tectonic: Area is bordered by the Mahanadi, Pranhita and Godaveri linear grabens / aulacogens rifts that have history of frequent reactivation; lineament study indicates that the area is under crustal tension with mantle reaching deep seated fault i.e. Sondur lineament etc; splay of secondary faults and intersection of linear fractures /fault corridors are common in the area; indicates an intersection of high permeability zone; dome shaped uplifts is displayed in fairly plastic sedimentary cover i.e.Khariar sediments, while block shaped uplifts occur in more rigid cover rocks or within outcrops of basement on craton (Bastar craton). Lithologic: Most of the craton part in the Mainpur-Deobhog Area (MDA) is represented by Archon and Proton; Presence of Khariar platform cover rock on the Bastar craton; the kimberlites always occur in cluster and four pipe rocks are already discovered; MDA is included in alkaline rock province. Geophysical: Geophysical (aeromagnetic) survey is in progress; high magnetic anomaly is reported; represents high boundary velocity (vp) and high gravity anomaly; area absolutely comes under low geothermal gradient. Geochemical: Streams sediments show dispersion halos of diamond indicator; Local diggers recover placer diamonds. |
The lithologic, tectonic, drainage maps and geochemical data of the selected window are digitized and used as database for KEGIS. The software used for development of KEGIS is ILWIS-2.1, developed by ITC, The Netherlands. The software gives highest flexibility and combines raster and vector based GIS, as some analytical technique can be best performed in vector mode while others in raster mode. The information is extracted from prepared thematic maps and finally six important 'attribute input data' are identified for further operation. The attribute input data are subjected to Fuzzy Logic Operation that is based on membership values given as attribute value, ranging between 0 & 1. The contact between Proterozoics and Archaeans and, the area occupied by coarse-grained granite are selected from the geological map and buffered to produce a proximity map. Similarly proximity map is derived from the structural map indicating distance of influence zone from the normal fault, which is used as an evidence for proximity to heat source. Based on distance from the center, the coarse grained granite is separated into 10 different zones and each zone is buffered. The geochemical data for elements Ni, Co and Cr, supposed to be important indicators for rocks of the kimerlite clan, is classified on a scale designed to accentuate and enhance those areas with anomalous high value of Ni (650 to 2000 ppm), Cr (400 to >1000 ppm), Co (40 to 200 ppm). Choosing anomalous drainage patterns enhances the drainage map and allows preparing the derivative map. The attribute data and the assumptions are combined together in the base buffer zone to be used in KEGIS.
Fig. 4. Geologic Map of Mainpur-Deobhog area
Fuzzy logical operation
All the available information that provides evidence for kimberite exploration is combined together by means of fuzzy logical operation. The fuzzy logical operation is used for the development of KEGIS as fuzzy logic allows for more flexible combinations for weighted information and can be readily implemented with a GIS modeling language. All these are based on subjective empirical models linked to weights or fuzzy memberships values assigned subjectively using knowledge of the process involved to estimate the relative importance of the input map. This is carried out in stages, with the ultimate product being a predictive map indicating the relative favourability of kimberlite emplacement. The combination processes involves weighing and fusion of evidence carried out in a number of different ways.
Fuzzy membership functions are subjectively assigned weight to each type of evidences, thereby controlling the relative weighting of the data. Alternatively, the evidences could have been weighted statistically, using the observed association of the evidence map with known occurrences of kimberlite pipes. Several operations can be employed using the evidence maps with combination of fuzzy membership value together. For the development of KEGIS, fuzzy algebraic product, fuzzy algebraic sum and, fuzzy gamma operations are deployed.
Fuzzy algebraic product
With combination of all six evidence maps and the employed fuzzy algebraic product, the combined membership function is defined as
Where µ = Fuzzy membership value for ith map
And, i = 1 to 6 (evidence maps are combined)
The combined fuzzy membership values tend to be very small with this operator, due to effect of multiplying several numbers less than 1. The output is always smaller than or equal to the smallest contributing membership value and is therefore, "decreasive".
Fuzzy algebraic sum
This operator is complementary to the algebraic product, defined as.
Where µ = Fuzzy membership value for ith map
And, i = 1 to 6 (evidence maps are combined)
The result is always larger (or equal to the largest) contributing fuzzy membership value. The effect is therefore, "increasive".
Two pieces of that both evidences favouring a hypothesis are reinforced into one another and the combined evidences are more supportive than either piece of evidence taken individually. In case of present investigation fuzzy algebraic sum of (0.95, 0.1) is 1(1-0.95) X (1-0.1) that is equal to 1.0 (FMV).
The increasive effect of combining several favourable pieces of evidences is automatically limited by the maximum value 1.0, which can never be exceeded. Note that, whereas the fuzzy algebraic product is an algebraic product, the fuzzy algebraic sum is not an algebraic summation.
Gamma operation (Gamma = 0.95)
Fuzzy algebraic sum and fuzzy algebraic product were combined together by means of Gamma operation. This is defined in terms of
Combination = (Fuzzy algebraic sum) x ? (Fuzzy algebraic product) (1- ?)
Where ? is parameter chosen in the range (0,1)
When ? is 1, the combination is same as the fuzzy algebraic sum and when ? is 0, the combination is equal to the fuzzy algebraic product. Judicious choice of g produce output values that ensure a flexible compromise between the "increasive" tendencies of the fuzzy algebraic sum and the "decresive" effects of fuzzy algebraic product. The data integration and combination of Fuzzy operation results obtained during KEGIS are used in development of strategy for Kimberlite exploration.
Target area for kimberlite exploration
The prioritization of smaller potential segments for kimberlite exploration takes into account the GIS result, permutation and combination of different exploration data and extensive field database. Through, the kimberlite occurs in clusters, in a given geologic environment the various kimberlite clusters may be separated in space and time. The concentration of diamond and other heavy minerals at the suitable placer locations provide indication for intensity of kimberlite occurrences in any area. The occurrence of diamonds at Sinapali (adjacent to MDA but lying in the state of Orissa and, a trading center for diamonds and other minerals) in placer invariably points towards possible large number of primary sources, located upstream areas falling within MDA. One of the major hindrances in identification of kimberlite in MDA is its small dimension and level of erosion since emplacement. The kimberlite pipes, in general, occur with negative topographic expression and are expected to be picked up in low attitude, closely spaced (200 m X 200 m or even less) aeromagnetic data. Since, on legal ground these data are not available to users, identification of target area for kimberlite exploration remains vague in a sense.
The result of KEGIS yields a fuzzy gamma, which is finally classified on the basis of the histogram of fuzzy membership value. The five probability classes are identified in which fuzzy membership value less than 0.63 indicate low possibility of kimberlite occurrence, where as fuzzy membership value in 0.81 to 0.95 range indicates very high possibility of kimberlite occurrence.
The identified potential zone for kimberlite exploration through KEGIS has limitations. The technique is primarily centered on known kimberlite occurrences and is based on averaging of all observed factors. However, based on real world field data and other exploration guides, priority zones for kimberlite targeting are identified.
Acknowledgements
MSK thanks the DGM, Govt. of M. P. for necessary permission and the IIRS, Dehra Dun for laboratory support.
Suggested readings
- Clifford TN, 1966. Tectono-metallogenetic units and metalogenic province of Africa. Earth planetary Science letters, 1, pp. 421-434.
- Smirnov YD, 1993. Structural setting of the Kimberlites of the east European craton. Intern Geol. Rev. 35:264-270.
- Verma PK, 1993. Tectonic inferences from the statistical treatment of the remote sensing lineament fabric data associated with the Great Boundary Fault of Rajasthan, India. Jour. Indian Society of Remote Sensing (Photonirvachak), vol 21, No.2.
- Verma P. K. 1999. Deep continental structures and processes in the Aravalli mountain range, NW India: Focus on evolution and inversion of regional faults. DCS-DST News Letter. Vol. 9, No. 2, pp. 21-24.
- Verma P. K. 2000. Integration of remote sensing and other geophysical data for identification and mapping of regional tectonic elements in the Aravalli mountain range, Northwest India. International Conference on Remote Sensing/GIS/GPS, Hotel Taj Palace, New Delhi. pp. 5-8.
- White SH, De Boorder H and Smith CB, 1995. Structural controls on the emplacement of Kimberlites and Lamproites. In: W.L. Griffin (Editor), Diamond exploration into the 21st Century. J. Geochem. Explor., 53:245-264.
Fig. 5a Lineament intersection density map of MDA
Note the High lineament density girdles that are also favourable sites for kimberlite occurrences.
Fig. 5b Rose diagramme for lineaments of MDA.
The N-S trends are dominated in the Eastern Ghat rocks, the NW-SE trends are prominent in Basement granitic terrain while the Khariar sediments are characterized by NE-SW trending lineaments.