Radioelements and heat production of an exposed Archaean crustal cross-section, Dharwar craton, south India

Kumar, Prakash; Reddy, G. K.

doi:10.1016/j.epsl.2004.05.032

Cited by 50 publications

(35 citation statements)

References 42 publications

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“…The natural crustal cross-section inferred for the Dharwar craton shows that the *400 km long and 30-50 km wide Closepet Granite batholith, is exposed in a crustal cross section of *15 km from greenschist facies crustal level in the north through amphibolite-to-granulite facies transition in the south (2.5-7 kbar). Extensive measurements of radioelemental abundances (K, U and Th) over the batholith confirm a strong variation in heat production in the granitoid from greenschist facies crustal level (average, 4.9 lW m -3 ) to granulite facies crustal level (average 1 lW m -3 ) (Kumar and Reddy 2004). However, no heat flow data were available to examine the relationship between heat flow and heat production in the batholith, except at one site close to the margin with migmatitic gneiss (Fig.…”

Section: Introductionmentioning

confidence: 94%

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Roy

Ray

Bhattacharya

et al. 2007

Int J Earth Sci (Geol Rundsch)

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The Late Archaean Closepet Granite batholith in south India is exposed at different crustal levels grading from greenschist facies in the north through amphibolite and granulite facies in the south along a *400 km long segment in the Dharwar craton. Two areas, Pavagada and Magadi, located in the Main Mass of the batholith, best represent the granitoid of the greenschist and amphibolite facies crustal levels respectively. Heat flow estimates of 38 mW m -2 from Pavagada and 25 mW m -2 from Magadi have been obtained through measurements in deep (430 and 445 m) and carefully sited boreholes. Measurements made in four boreholes of opportunity in Pavagada area yield a mean heat flow of 39 ± 4 (s.d.) mW m -2 , which is in good agreement with the estimate from deep borehole. The study, therefore, demonstrates a clear-cut heat flow variation concomitant with the crustal levels exposed in the two areas. The mean heat production estimates for the greenschist facies and amphibolite facies layers constituting the Main Mass of the batholith are 2.9 and 1.8 lW m -3 , respectively. The enhanced heat flow in the Pavagada area is consistent with the occurrence of a radioelement-enriched 2-km-thick greenschist facies layer granitoid overlying the granitoid of the amphibolite facies layer which is twice as thick as represented in the Magadi area. The crustal heat production models indicate similar mantle heat flow estimates in the range 12-14 mW m -2 , consistent with the other parts of the greenstone-granite-gneiss terrain of the Dharwar craton.

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Section: Introductionmentioning

confidence: 94%

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Roy

Ray

Bhattacharya

et al. 2007

Int J Earth Sci (Geol Rundsch)

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“…This leads us to believe that the EDC was hotter than many other shield regions of the world in the mid-Proterozoic period when kimberlites intruded the craton. This can be attributed, following the present-day heat flow model of Senthil Kumar and Reddy (2004), to high mantle heat flow beneath the EDC in the mid-Proterozoic time.…”

Section: à2mentioning

confidence: 99%

Mafic xenoliths in Proterozoic kimberlites from Eastern Dharwar Craton, India: Mineralogy and P–T regime

Patel¹,

Ravi

Anilkumar³

et al. 2009

Journal of Asian Earth Sciences

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“…However, this has not been the case. In many geological situations, it has been found that the measured heat production is considerably higher than normally assumed, at least till about mid-crustal level, for example, Vredefort granitic basement of Kaapvaal craton (Nicolaysen et al, 1981), central southern Alps region of the South Island, New Zealand (Pandey, 1981) and Archean Dharwar crust of India (Senthil Kumar and Reddy, 2004). Such midcrustal enrichment has been explained by lithology-related variations in heat producing elements.…”

Section: Discussionmentioning

confidence: 99%

“…Present day exposed crustal configuration comprises four metamorphic facies layers, green schist, amphibolites, metasomatized granulite and depleted granulites. Heat production vs. depth distribution has been studied in detail for the Closepet granitic batholithic region (Senthil Kumar and Reddy, 2004) situated in the central part of the craton which itself exposes almost 12 km deep section corresponding to palaeo-depth between 8 and 20 km. To this data, we have added, the recently acquired heat production data pertaining to sub-surface mid-crustal amphibolite-granulite facies rocks from Killari region (Maharashtra, India) belonging to similar terrain, and lower crustal granulitic heat production data from the Southern granulite terrain of south India (Ray et al, 2003).…”

Section: Dharwar Craton (Southern India)mentioning

confidence: 99%

Fractal behavior in continental crustal heat production

Vedanti

Srivastava

Pandey

et al. 2011

Nonlin. Processes Geophys.

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Abstract. The distribution of crustal heat production, which is the most important component in the elucidation of continental thermal structure, still remains a theoretical assumption. In general the heat production values must decrease with depth, but the form of decrease of heat production in the crust is not well understood. The commonly used heat production models are: "block model", in which heat production is constant from the surface to a given depth and the "exponential model", in which heat production diminishes as an exponential function of depth. The exponential model is more widely used wherein sources of the errors are heterogeneity of rock and long wavelength changes due to changes in lithology and tectonic elements, and as such exponential distribution does not work satisfactorily for the entire crust. In the present study, we analyze for the first time, deep crustal heat production data of six global areas namely Dharwar craton (India), Kaapvaal craton (South Africa), Baltic shield (Kola, Russia), Hidaka metamorphic belt (Japan), Nissho pluton (Japan) and Continental Deep Drilling site (KTB, Germany). The power spectrum of all the studied data sets exhibits power law behaviour. This would mean slower decay of heat production with depth, which conforms to the known geologic composition of the crust. Minimum value of the scaling exponent has been found for the KTB borehole, which is apparently related to higher heat production of gneisses, however for other study areas, scaling exponent is almost similar. We also found that the lower values of scaling exponents are related to higher heat production in the crust as is the case in KTB. Present finding has a direct relevance in computation of temperature-depth profiles in continental regions.

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Radioelements and heat production of an exposed Archaean crustal cross-section, Dharwar craton, south India

Cited by 50 publications

References 42 publications

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Mafic xenoliths in Proterozoic kimberlites from Eastern Dharwar Craton, India: Mineralogy and P–T regime

Fractal behavior in continental crustal heat production

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