scholarly journals Application of 2D Resistivity Modelling to Delineate Lamproites in Parts of North‑Eastern Dharwar Craton

2022 ◽  
Author(s):  
Ravi Jonnalagadda ◽  
Ram Raj Mathur
Keyword(s):  
Country Rock ◽  
Electrical Response ◽  
Geophysical Methods ◽  
Dharwar Craton ◽  
Source Rocks ◽  
Cuddapah Basin ◽  
Eastern Dharwar Craton ◽  
Electrical Method ◽  
North Eastern ◽  
2D Resistivity

Abstract Geophysical methods have extensively been used in exploration of Lamproite bodies. Lamproites are significant source rocks of primary diamond deposits other than Kimberlites. The Eastern Dharwar Craton is unique in the way that it hosts numerous Precambrian Lamproites confined to the crescent-shaped Paleo-Mesoproterozoic Cuddapah Basin and its north-western and north-eastern margins. In the present study electrical method was used as a tool for delineation of Lamproite bodies in contrast with country rocks in Gundrapally, Vattikode and Marepally regions in parts of the North Eastern Dharwar Craton in Telangana State, India. The electrical profiling method was conducted in different direction to identify the variation of the lithology of the area due to the anisotropic nature and smaller size of the 2-D intrusive bodies adopting the Wenner electrode configuration. The electrical properties of the Lamproites tended to change with their composition due to weathering and the presence of Olivine and K-Al rich composition. The electrical response on the Lamproite pipes is shows a decrease in resistivity concerning the country-rock in the area.

Petrogenesis of an alkaline lamprophyre (camptonite) with ocean island basalt (OIB)-affinity at the NW margin of the Cuddapah basin, eastern Dharwar craton, southern India

2019 ◽  
Vol 196 (2) ◽  
pp. 149-177 ◽  
Author(s):  
Rohit Kumar Giri ◽  
Praveer Pankaj ◽  
N.V. Chalapathi Rao ◽  
Ramananda Chakrabarti ◽  
Dinesh Pandit
Keyword(s):  
Mantle Source ◽  
Dharwar Craton ◽  
Southern India ◽  
Striking Similarity ◽  
Cuddapah Basin ◽  
Eastern Dharwar Craton ◽  
Calc Alkaline ◽  
Western Margin ◽  
Ocean Island ◽  
Alkaline Lamprophyres

We report petrology and geochemistry (including Sr and Nd isotopes) of a fresh lamprophyre at Ankiraopalli area at the north-western margin of Paleo-Mesoproterozoic Cuddapah basin, eastern Dharwar craton, southern India. Ankiraopalli samples possess a typical lamprophyre porphyritic-panidiomorphic texture with phenocrysts of kaersutite and diopside set in a plagioclase dominant groundmass. Combined mineralogy and geochemistry classify it as alkaline lampro- phyre in general and camptonite in particular. Contrary to the calc-alkaline and/or shoshonitic orogenic nature portrayed by lamprophyres occurring towards the western margin of the Cuddapah basin, the Ankiraopalli samples display trace element composition revealing striking similarity with those of ocean island basalts, Italian alkaline lamprophyres and highlights an anorogenic character. However, the87 Sr/86 Srinitial (0.710316 to 0.720016) and εNdinitial (– 9.54 to – 9.61) of the Ankiraopalli lamprophyre show derivation from an 'enriched' mantle source showing long term enrichment of incompatible trace elements and contrast from those of (i) OIB, and (ii) nearby Mahbubnagar alkaline mafic dykes of OIB affinity. Combining results of this study and recent advances made, multiple mantle domains are identified in the Eastern Dharwar craton which generated distinct Mesoproterozoic lamprophyre varieties. These include (i) Domain I, involving sub-continental lithospheric mantle source essentially metasomatized by subduction-derived melts/fluids (represented by orogenic calcalkaline and/or shoshonitic lamprophyres at the Mudigubba, the Udiripikonda and the Kadiri); (ii) Domain II, comprising a mixed sub-continental lithospheric and asthenospheric source (represented by orogenic-anorogenic, alkaline to calc-alkaline transitional lamprophyres at the Korakkodu), and (iii) Domain III, representing a sub-continental lithospheric source with a dominant overprint of an asthenospheric (plume) component (represented by essentially alkaline lamprophyres at the Ankiraopalli). Our study highlights the varied mantle source heterogeneities and complexity of geodynamic processes involved in the Neoarchean-Paleo/Mesoproterozoic evolution of the Eastern Dharwar craton.

Petrology and petrogenesis of Mesoproterozoic lamproites from the Ramadugu field, NW margin of the Cuddapah basin, Eastern Dharwar craton, southern India

Lithos ◽  
2014 ◽  
Vol 196-197 ◽  
pp. 150-168 ◽  
Author(s):  
N.V. Chalapathi Rao ◽  
Alok Kumar ◽  
Samarendra Sahoo ◽  
A.N. Dongre ◽  
Debojit Talukdar
Keyword(s):  
Dharwar Craton ◽  
Southern India ◽  
Cuddapah Basin ◽  
Eastern Dharwar Craton
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