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P. R. Golani ¹, R. C. Gathania ¹, A. K. Grover ¹, J. Bhattacharjee ¹

Affiliations
1 Geological Survey of India, Jhalana Dungri Complex, Jaipur 302 004, IN

Abstract

Felsic volcanics in the south Khetri Copper Belt (KCB) occur interlayered with fine grey banded phyllitic quartzite which often contains fine carbonaceous matter. The volcanics include crystal tuff, ultrafinely laminated grey tuff and pumice. They have been recognised in field on the basis of vesicles and rare amygdules; and under microscope by embayed and resorbed quartz phenocrysts. Glass is altered and incipiently recrystallised. Devitrification textures like spherulites are intact in rare cases. The relatively unaltered tuffs fall in dacitic field of Total Alkali-Silica (TAS) diagram. The tuffs are intimately associated with baryte and ironstone layers at places. Recent work in the south KCB indicates that sulfide mineralisation is polymetaHic. It is stratabound hosted by felsic volcanics and fine carbonaceous phyllite and quartzite. The mineralised zones show wall-rock alteration in the form of profuse silicification and sericitisation. These features when seen in conjunction with the occurrence of concordant baryte and ironstone layers, indicate that the sulfide mineralisation is volcanic-exhalative type.

Keywords

Felsic Volcanics, Khetri Copper Belt, Rajasthan, Economic Geology.

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A. K. Grover ¹, R. G. Verma ¹

Affiliations
1 Geological Survey of India, Western Region, 15-16, Jhalana Dungri, Jaipur-302 004, IN

Abstract

Several; ancient mines or old working exist in the vicinity of Bhukia village near Ghatol in Banswara district, Rajasthan, within Precambrian metamorphosed volcano-sedimentary rocks. These old workings/mines were earlier explored for base metals, specially for copper. Recent work carried out in this part indicated prcsence of native gold in visible form in some of the grab samples taken from two mine dumps. The maximum size of gold flake noticed is 4x2 mm. Higher gold values are generally associafed with high copper and arsenic values. This suggests re- examination of the ancient mines and certain lithounits present between Salumbar and Banswara, southeastern Rajasthan for gold.

Keywords

Gold Precambrians, Rajasthan, Economic Geology.

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A. K. Grover ¹, R. G. Verma ¹

Affiliations
1 Geological Survey of India, Western Region, 15-16, Jhalana Dungri, Jaipur - 302 004, IN

Abstract

Preliminary sampling of old workings have indicated gold mineralisation in a geological set-up similar to Bhukla gold prospect. This find suggests a northward extension of the Bhukia-Kundli auriferous tract by at least 10 Km.

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A. K. Grover ¹

Affiliations
1 Geological Survey of India, 15-16, Jhalana Institutional Area, Jaipur - 302 004, IN

Abstract

The recent find of gold mineralisation in the Precambrians of Bhukia-Jagpura area in southeastern Rajasthan, was based on the identification of native gold flakes in the gossan in close vicinity of old workings. Detailed investigation in the area has brought out the presence of physical evidences of gold extraction from the auriferous ores by ancient prospectors, in the form (i) ancient gold panning sites and (ii) stone grinding implements. The panning sites exhibit special characters in comparison to the sites of commonly known riverside gold panning activities. The stone grinding implements include pestles, mortars and Poly-Mortars, which however, are similar to those already reported from other parts of India. A widespread presence of these features in Bhukia-Jagpura prospect and adjoining areas indicates towards the existence of a flourishing gold winning industry in southeastern Rajasthan during recent past. Identification of such ancient gold panning sites and implements can form a tool in locating new gold prospects.

Keywords

Ancient Gold Panning Sites, Stone Grinding Implements, Pestle, Mortar, Poly-Mortar, Bhukia-Jagpura, Southeastern Rajasthan.

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P. R. Golani ¹, D. Bhattacharyya ², S. Sanyal ², I. R. Kirmani ², G. Malhotra ², S. Bhattacharyya ², A. K. Grover ², J. L. Narang ²

Affiliations
1 Geological Survey of India, A.M.S.E. Wing, Central Zone, Seminary Hills, Nagpur - 440 006, IN
2 Geological Survey of India, Western Region, 15-16, Jhalana Dungri, Jaipur - 302 004, IN

Abstract

The Deldar-Kui-Chitrasani (DKC) fault is a brittle structure manifested by anastomosing system of fractures in the southwestern part of the South Delhi Fold Belt (SDFB). Based on the identification of cross-fibre and 'jigsaw puzzle' type structures, presence of vugs lined with cryptocrystalline quartz, replacement of calcite by chalcedonic quartz and evidences of argillic alteration, the breccia along the fault is recognised by present workers as epithermal breccia. Lithogeochemical sampling of the breccia reveals that, besides moderate base metal signatures, gold values are consistently present in significant concentrations comparable to regional anomalies associated with epithermal gold deposits in the United States. In view of the high proportion of magmatic rocks in the southwestern part of the SDFB, the DKC fault zone is considered a favourable target for searching epithermal type of gold mineralisation.

Keywords

Economic Geology, Epithermal Breccia, Lithogeochemistry, Gold Anomaly, Faults, Shear Zone, South Delhi Fold Belt, Rajasthan, Gujarat.

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A. K. Grover ¹

Affiliations
1 (formerly at Geological Survey of India) lives at H. No. 104, Milap Nagar, Tonk Road, Jaipur 302 018, IN

Abstract

No Abstract.

Keywords

No Keywords.

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