Geochronological constraints on evolution of Singhbhum mobile belt and associated basic volcanics of eastern Indian Shield—reply

2006 ◽  
Vol 9 (4) ◽  
pp. 543-544 ◽  
Author(s):  
Saumitra Misra
Keyword(s):  
Mobile Belt ◽  
Indian Shield ◽  
Basic Volcanics ◽  
Geochronological Constraints

Petrogenesis and tectonic setting of bimodal volcanism in the Sakoli Mobile Belt, Central Indian shield

Island Arc ◽  
2009 ◽  
Vol 18 (1) ◽  
pp. 155-174 ◽  
Author(s):  
Talat Ahmad ◽  
Kabita C. Longjam ◽  
Baishali Fouzdar ◽  
Mike J. Bickle ◽  
Hazel J. Chapman
Keyword(s):  
Tectonic Setting ◽  
Mobile Belt ◽  
Indian Shield ◽  
Bimodal Volcanism

Curie depth point, effective elastic thickness, and 3-D crustal structure of Eastern Indian shield based on the interpretation of satellite gravity (GOCE) and aeromagnetic data.

2021 ◽  
Author(s):  
Rama Chandrudu Arasada ◽  
Srinivasa Rao Gangumalla
Keyword(s):  
Integrated Approach ◽  
Eastern Ghats ◽  
Gravity Modeling ◽  
Mobile Belt ◽  
Aeromagnetic Data ◽  
Indian Shield ◽  
Satellite Gravity ◽  
Effective Elastic Thickness ◽  
Curie Depth ◽  
Moho Depths

<p>Eastern Indian shield comprises rocks that well persevered the Archean to the Proterozoic history of the earth. However, the lithospheric evolution of the region is poorly understood due to the scanty of seismological observations. In the presented study, an integrated approach is adopted to analyze the satellite gravity (GOCE), aeromagnetic, and topography data complemented with seismological constraints to understand the thermal evolution of the region. Wavelet based Bouguer-topography coherence method was used to compute spatial variations of effective elastic thickness (Te) in the region. We noticed high Te values of 27-31 km over EGMB and low to moderate Te values of 22-30 km over SC and CGGC. Results of 3-D forward gravity modeling of Complete Bouguer anomalies show that the Moho boundary lies at a depth of 35-38 km below the Eastern Ghats Mobile Belt (EGMB) and 38-40 km below Singhbhum Craton (SC), and it increases gradually towards the Chotanagpur granite gneiss complex (CGGC) to a depth of 40-44 km. Curie depth point (CDP) values obtained based on the spectral analysis of aeromagnetic data range from 25-30 km beneath the EGMB, 23-26 km over SC, and 30-36 km beneath the CGGC. Further comparison of CDP values with Moho depths (35-44 km) from 3-D forward gravity modeling and available deep seismic sounding/receiver function data in this region indicate that CDP values are shallower than the Moho. Unlike other cratonic regions, the shallowest CDP and low Te values observed over the Eastern Indian Shield suggests thermal reworking of the cratonic lithosphere in this region.</p>

Explanatory notes to the Geological map of Greenland, 1:500 000, Humboldt Gletscher, Sheet 6

2004 ◽  
pp. 1-48
Author(s):  
Peter R. Dawes
Keyword(s):  
Coarse Grained ◽  
Mobile Belt ◽  
Nares Strait ◽  
General Terms ◽  
Mineral Occurrence ◽  
North Eastern ◽  
Copper Gold ◽  
High Grade Metamorphism ◽  
Geological Map ◽  
Map Series

NOTE: This Map Description was published in a former series of GEUS Bulletin. Please use the original series name when citing this series, for example: Dawes, P. R. (2004). Explanatory notes to the Geological map of Greenland, 1:500 000, Humboldt Gletscher, Sheet 6. Geological Survey of Denmark and Greenland Map Series 1, 48 pp. + map. https://doi.org/10.34194/geusm.v1.4615  _______________ These explanatory notes cover the map region bounded by latitudes 78°N and 81°N and longitudes 56°W and 74°W, with geology shown on the land areas between Nares Strait - the seaway between Greenland and Ellesmere Island, Canada - and the Inland Ice. The bedrock geology is composed of Precambrian and Lower Palaeozoic provinces that continue across Nares Strait into Canada. Map units and mineral occurrences are described in general terms and are proceeded by sections on physical environment, logistics, data sources and geoscientific research. The notes are aimed at the practical user and a guide for further reading. The bedrock is composed of three provinces separated by unconformities, each representing a hiatus of c. 500 Ma during which basic dykes were emplaced. The Palaeoproterozoic Inglefield mobile belt, forming the crystalline shield, is an E-W-trending belt of deposition and orogeny characterised by polyphase magmatism, deformation and high-grade metamorphism. Clastic deposition, with magmatism at c. 1985 Ma, are the oldest events recorded, followed by the accumulation of the Etah Group (carbonate, pelitic and psammitic sediments with supposedly coeval mafic and ultramafic rocks) between 1980 and 1950 Ma ago. These rocks were intruded 1950 to 1915 Ma ago by the Etah meta-igneous complex, that records polyphase plutonism (intermediate to felsic, with some basic and magnetite-rich rocks), followed by deformation and partial melting producing granites 1785 to 1740 Ma ago. The Mesoproterozoic Thule Basin, defined by the unmetamorphosed and little deformed Thule Supergroup, records sedimentation and basaltic volcanism at least as old as 1270 Ma. The faulted, north-eastern basin margin shown on the map preserves the passage from the basinal sequence to a relatively thin platform succession invaded by basic sills. The Palaeozoic Franklinian Basin is represented by a homoclinal Cambrian to Silurian shelf carbonate succession and a major Silurian reef complex, with coeval siliciclastic slope deposits. The map region includes the classical area for Franklinian stratigraphy, now composed of 29 formations and four groups - Ryder Gletscher, Morris Bugt, Washington Land and Peary Land Groups. The only younger units preserved in the map region are widespread Quaternary deposits, an isolated outcrop of coarse-grained fluvial deposits (Bjørnehiet Formation) and non-carbonised wood erratics of Neogene age. Five mineral occurrence types are shown on the map: in lithologies of the Inglefield mobile belt, sulphide-graphite rust zones, a magnetite deposit and copper-gold mineralisation and in the Franklinian Basin, commercially drilled, zinc-lead-silver and zinc-lead-barium mineralisations. The basic ingredients of a petroleum model exist in the Franklinian Basin but prospectivity is low.

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