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C. Murugan ¹, K. A. A. Kabeer ¹, G. V. S. Murthy ¹

Affiliations
1 Botanical Survey of India, Southern Regional Circle, Coimbatore 641 003, Tamil Nadu, IN

Abstract

No Abstract.

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C. Murugan ¹, J. V. Sudhakar ¹

Affiliations
1 Botanical Survey of India, Southern Regional Centre, Coimbatore 641 003, IN

Abstract

No Abstract.

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A. K. Dwivedi ¹, Joydip Sen ¹, C. Murugan ¹, G. Bairwa ¹, A. K. Bhatt ¹, P. V. Ramesh Babu ¹, S. A. Pandit ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Jamshedpur-831002, IN
2 Atomic Minerals Directorate for Exploration and Research, Hyderabad-500016, IN

Abstract

Hydrogeochemical exploration were earned out over an area of 700 sq km in Barabazar-Manbazar area of Purulia district, West Bengal, in order to identify target areas for the uranium mineralization. Water samples were collected from 504 borewells in the Singhbhum Group meta-Sediments and Chhotanagpur Granite Gneissic Complex (CGGC) including South Purulia Shear Zone (SPSZ). For individual Iithological domains, univariate and multivariate statistical techniques were applied to the analytical data on 10 variables, i.e. U, Na⁺, K⁺ , Mg⁺², Ca⁺², SO₄^-2, HCO₃, Cl^-, conductivity and pH. Five hydro uranium anomalous zones withm CGGC were delineated at Raghunathpur, Tentla, Chepua-Dighi, Ban and Jitujon areas. However, distinct pattern of high uranium values along with uranium/Conductivity are observed only in Raghunathpur-Tentla and Chepua-Dighi areas in the proximal tectonized zones of SPSZ. Based on the distinctive hydrogeochemical attributes, and favourable geology and structure, the areas in the vicinity of Raghunathpur-Tentla and Chepua-Dighi in the northern proximal contact of SPSZ, are designated as potential target areas for detailed geological and geophysical exploration.

Keywords

Hydrogeochemistry, Uranium, SPSZ, CGGC, Singhbhum Group, Purulia, West Bengal.

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A. K. Dwivedi ¹, U. K. Pandey ¹, C. Murugan ¹, A. K. Bhatt ², P. V. Ramesh Babu ¹, Mallikarjun Joshi ³

Affiliations
1 Atomic Minerals Directorate for Exploration and Research (AMD), Hyderabad - 500629, IN
2 Atomic Minerals Directorate for Exploration and Research (AMD), Jamshedpur - 831 002, IN
3 Banaras Hindu University, Varanasi - 221005, IN

Abstract

The Barabazar granite, exposed at the northern margin of Singhbhum craton, Eastern India, occurs along the South Purulia Shear Zone (SPSZ) and is emplaced into the Palaeoproterozoic metapelites and felsic volcanics of Singhbhum Group. Geochemical, petrographical and geochronological studies on the Barabazar granite addressed in the work have wide implications on understanding the geodynamics of SPSZ during Palaeoproterozoic to Mesoproterozoic. Geochemically, Barabazar granite displays limited range of major oxides, alkali enrichment and highly fractionated features (SiO₂ > 75%; Eu/Eu^* = 0.16-0.33; enrichment of K, Rb, Th, U and Nb; depletion of Ba, Sr, P and Ti). It is predominantly peraluminous (molar Al₂O₃/CaO+Na₂O+K₂O (A/CNK) = 1.14-144) and contains abundant alkali feldspar, perthite, and minor plagioclase, biotite and accessory minerals. Geochemical and petrological data indicates that it is A-type granite, which formed in 'Within plate granite' tectonic set up. The Barabazar granite was emplaced at ca. 1771 Ma (Pb-Pb) in rift related environs and evolved by partial melting of stabilized lower/middle crust (initial ⁸⁷Sr/⁸⁶Sr = 0.7302 ± 0.0066 and μ₁ = 8.5 ± 0.5). Subsequently, the shear zone (SPSZ) developed during the closure of the riftogenic basin and was reactivated during the Grenvillian orogeny (Ca. 900-1300 Ma), resulting in rehomogenisation of the strontium isotopes and thereby yielding younger whole-rock Rb-Sr isotope age of c. 971 Ma for the Barabazar granite. Probably during this tectonic event, the Singhbhum craton (Southern India Shield) would have finally juxtaposed with Northern Indian Shield along Central Indian Tectonic Zone (CITZ) during the global Grenvillian orogeny.

Keywords

A-Type Barabazar Granite, Geochemistry, Geochronology, Grenvillian Orogeny, Singbhhum Craton, SPSZ, West Bengal.

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S. Arumugam ¹, V. Ravichandran ¹, R. Manikandan ¹, C. Murugan ¹

Affiliations
1 Botanical Survey of India, Southern Regional Centre, Lawley Road Post, TNAU Campus, Coimbatore – 641 003, Tamil Nadu, IN

Abstract

Drypetes porteri (Gamble) Pax & K. Hoffm. is rediscovered after type collection (121 years) from type locality from Megamalai Wildlife Sanctuary, southern Western Ghats, Tamil Nadu, India. Lectotypification, brief description amended with fruit morphology and colour photographs are provided here for easy identification.

Keywords

Drypetes, Endemic, Lectotype, Megamalai.

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Jeewan Singh Jalal ¹, Chaya Deori ², C. Murugan ¹, N. Odyuo ², B. S. Kholia ³, David Lalsama Biate ², S. R. Talukdar ², Y. Mahesh ²

Affiliations
1 Botanical Survey of India, CGO Complex, 3rd MSO Building, Salt Lake City, Kolkata-700064, IN
2 Botanical Survey of India, Eastern Regional Centre, Lower New Colony, Laitumkhrah, Shillong-793003, IN
3 Botanical Survey of India, Northern Regional Centre, 192, Kaulagarh Road, Dehradun-248195, IN

Abstract

Spathoglottis affinis de Vriese is reported for the first time from India based on specimens collected from Meghalaya. A brief description, photographic illustration, along with information on flowering, habitat and distribution have been provided to facilitate its identification. Its Red list status has been assessed as ‘Vulnerable’ as per IUCN guidelines.

Keywords

Jaintia Hills, Meghalaya, Orchidaceae, Taxonomy, Distribution

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