A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
, Fareeduddin
- Gold Mineralisation in Salumbar-Parsola Area of Aravalli Fold Belt of Southeastern Rajasthan
Authors
1 Geological Survey of India, Project-Gold, Jaipur - 302 004, IN
2 Geological Survey of India, PPOD, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 63, No 5 (2004), Pagination: 494-506Abstract
Exploration work during 1993-97 in 1000 km2 area extending from Salumbar to Parsola has led to recognition of several gold bearing zones in almost all horizons of lower Aravalli sequence starting right from basal quartzite to pebbly schist/conglomerate except perhaps in schistose rocks. In general, gold content of lowermost rocks like basal quartzite and meta-basalts is lower (mean gold:90 ppb and 106 ppb respectively) than the gold contents of rocks of upper horizons like dolomitic marble-I, dolomitic marble-I1 and composite-gneiss (mean gold:452 ppb, 361 ppb, 191 ppb respectively). In addition to locating gold mineralisation in Rajpura, Padwa, Kukra, Dhaulimagri, Bhungabhat, Amalva-Dagocha-Rathri, Barasarpatia and Mokpura areas in dolomite marble, potential gold zones in sheared quartzite and gneiss are identified in Bhabrana, Navagaon, Dhuntarnagra and Jaitana-Mandii areas. Gold mineralisation is shear controlled and is associated with structural elements of both the first and second deformations. Vast gold potential of Aravalli fold belt (AFB) has been indicated by the presence of deep-ischolar_mained faults, boron bearing rocks/minerals, silicification/jasperization and highly anomalous gold contents in stream sediment (up to 910 ppb) and lithogeocll&nical samples (mean: 301 ppb, maximum: 6500 ppb).Keywords
Gold, Exploration, Genetic controls, Aravalli fold belt, Proterozoic, Salumbar, Parsola, Rajasthan.
- Carbonaceous Metaexhalite of Shungitic Affinity in Palaeoproterozoic Aravalli Supergroup, Dugocha Area, Rajasthan
Authors
1 PROD Division, AMSE Wing, Geological Survey of India, Eshwar Nagar, Bangalore -560 082, IN
2 AMSE Wing, WZ, Geological Survey of India, Jhalana Dungri, Jaipur - 302 004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 63, No 5 (2004), Pagination: 522-532Abstract
The Palaeoproterozoic Debari Group of Aravalli Supergroup near Dugocha, Rajasthan exposes carbonalbite-tourmaline bearing exhalite rock termed carbonaceous metaexhalite. This unit occurs within dolomites of Jagpura Formation and hosts gold-bismuth bearing sulphide mineralisation either within it or along dolomite-metaexhalite contact zones. Polyphase deformation and mineral recrystallisation under green schist facies of metamorphism characterise these rocks.Geochemically, the carbonaceous metaexhalites have a wide silica range (51 wt% to 63 wt%) and high total alkali (7.85 wt % to 13.20 wt%). EPMA studies of silicates indicate that the main feldspar in the rock is albite and the tourmalines are richer in titanium and chromium. The associated sulphides possess high salinity fluid inclusions (up to 19 wt% NaCl equivalent) and δ34S isotopic values of 12-14 permil. The latter values match well with those of the modern hydrotherms along Discovery Deep median trench of Red Sea.
The most outstanding feature of the rock is abundant carbon and its distribution pattern vis-a-vis associated silicates. The carbon distributed mainly as tiny graphite flakes of low order crystallinity often exceeds 30% by volume and analyses upto 15% by weight. There is an intimate intergrowth of the carbonaceous matter and the composite silicates that gives unique identity to the rock as for the texture and constituent minerals. These features together with their similar age and geological set-up have been discussed in terms of these rocks being similar to the multi-utility carbonaceous rocks with high economic significance found in Shunga Region, Karelia, Russia called Shungites. These high sodacarbon rocks are interpreted here as metamorphic products of mixed volcanic-clastic-exhalite facies rocks (felsic lavas, tuffs, exhalite and carbonate rocks) or the metamorphosed product of the original soda-carbonate volcanic flows during initial stages of Aravalli ensialic rifts.
Keywords
Carbon, Shungite, Albite-Graphite-Tourmaline Metaexhalite, Gold, Proterozoic, Aravalli, Debari, Dugocha, Rajasthan.- Applied Geochemistry in the Coming Decades
Authors
1 AMSE Wing, Geological Survey of India Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 62, No 1 (2003), Pagination: 124-125Abstract
No Abstract.Full Text
- Three New Candidate Rock Standards: Granite, Dunite and Anorthosite from Geological Survey of India, Bangalore
Authors
1 PPOD Division, AMSE Wing, Geological Survey of India, Bangalore - 560 070, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 59, No 3 (2002), Pagination: 273-275Abstract
Petrology, Petrochemistry and Ore Dressing (PPOD) Laboratories of the Airborne Mineral Surveys and Exploration (AMSE) Wing, Geological Survey of India, Bangalore has taken up the preparation of three International Rock Standards/Geostandards of a granite from Chamundi Hills, Mysore (designated as GSI-CG-1), a serpentinised dunite from Dodkanya dunite/magnesite mines, Mysore District (designated as GSI-DD-1) and an anorthosite from the Sittampundi Anorthosite Complex, Salem District, Tamil Nadu (designated as GSI-SA-1). Details of the three rock-standards are provided here for participative collaboration of interested geochemcial laboratories.Full Text
- Recent Developments in Geology and Mineral Resources of Central India
Authors
1 Geological Survey of India, AMSE Wing, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 74, No 3 (2009), Pagination: 421-421Abstract
No Abstract.Full Text