Geochemistry and Petrogenesis of Amphibolites, Kolar Schist Belt, South India: Evidence for Komatiitic Magma Derived by Low Percentages of Melting of the Mantle

Rajamani, V.; Shivkumar, K.; Hanson, Gilbert N.; Shirey, and S. B.

doi:10.1093/petrology/26.1.92

Cited by 141 publications

(63 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9) may be used to evaluate melting or differentiation processes of the mantle (Rajamani et al, 1985;Knoper and Condie, 1988). Fractional crystallisation and batch melting trajectories are distinguished on these diagrams of compatible (Cr) and incompatible elements (Zr N ).…”

Section: Trace Element Modelling and Petrogenesismentioning

confidence: 99%

“…(Smithies, 2002;open square), average Archaean norites (Nielsen et al, 2002;filled triangle), and average early Proterozoic norites (Hall and Hughes, 1987;filled diamonds). values used for modelling purposes. Another petrogenetic model based on Ni-Zr, established by Rajamani et al (1985) has also been tested for these rocks. Rajamani et al (1985) have suggested that a rock suite generated from different degrees of melting of the same source should have similar trend to melting curves presented in Fig.…”

Section: Trace Element Modelling and Petrogenesismentioning

confidence: 99%

“…Another petrogenetic model based on Ni-Zr, established by Rajamani et al (1985) has also been tested for these rocks. Rajamani et al (1985) have suggested that a rock suite generated from different degrees of melting of the same source should have similar trend to melting curves presented in Fig. 9b.…”

Section: Trace Element Modelling and Petrogenesismentioning

confidence: 99%

See 2 more Smart Citations

Geochemistry and petrogenesis of Neoarchaean high-Mg low-Ti mafic igneous rocks in an intracratonic setting, Central India craton: Evidence for boninite magmatism

Srivastava

2006

Geochem. J.

View full text Add to dashboard Cite

The southern Central India craton (also known as Bastar craton) has experienced several episodes of mafic magmatism during the early Precambrian time. These mafic igneous rocks are emplaced as dyke and volcanic rocks. A set of mafic dyke swarm and few exposures of mafic volcanics, both emplaced in the Neoarchaean time, contain high-SiO 2 (>52 wt%), high-MgO (>8 wt%), and low-TiO 2 (mostly <0.5 wt%) and classified as boninites on IUGS classification scheme. Al 2 O 3 / CaO ratio classifies these high-Mg mafic igneous rocks into high-Ca and low-Ca (Type 3) boninites. High-Ca boninites show typical boninitic geochemical characteristics, whereas low-Ca variety shows geochemical characteristics similar to the high-Mg norites. Siliceous high-magnesium basalts (SHMB) show similar geochemical properties as observed for the high-Mg norites. Early Precambrian high-Mg norites are reported from the rift setting environment but, on the other hand, boninitic magmatism represents an enigmatic style of magmatism and commonly formed at convergent margin settings. Most boninites are Phanerozoic in age and rarely reported from the Archaean terrains. The established geological and tectonic setting of the Archaean Bastar craton clearly suggests existence of a stable continental rift environment in the region since the Archaean time. Thus, report of Neoarchaean boninite-like rocks in an intracratonic setting is an important feature noticed in the Archaean terrain of Indian peninsula. A highly refractory mantle source region is required to form boninitic magma. Refractory lithosphere may be result of extensive extraction of mafic magma during Mesoarchaean. The preservation of refractory reservoir beneath the Bastar craton for long period of time corroborates a high degree of crustal stability during the Meso-Neoarchaean time. Trace element modelling suggests that high-Mg mafic igneous rocks under study are product of different pulses of boninitic magma produced by ~20-25% melting of a refractory mantle source.

show abstract

Section: Trace Element Modelling and Petrogenesismentioning

confidence: 99%

Section: Trace Element Modelling and Petrogenesismentioning

confidence: 99%

See 1 more Smart Citation

Geochemistry and petrogenesis of Neoarchaean high-Mg low-Ti mafic igneous rocks in an intracratonic setting, Central India craton: Evidence for boninite magmatism

Srivastava

2006

Geochem. J.

View full text Add to dashboard Cite

show abstract

“…However, except for those in the Dharwar craton (Drury, 1983;Rajamani et al, 1985;Weaver, 1990;Anand et al, 2003;Halls et al, 2007 and references therein), very few petrological and geochemical data are available on these rocks. Practically no isotopic data are available for the mafic igneous rocks exposed in the Bastar craton.…”

Section: Introductionmentioning

confidence: 99%

Sr–Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

2009

View full text Add to dashboard Cite

SummarySr-Nd isotope data are reported for the early Precambrian sub-alkaline mafic igneous rocks of the southern Bastar craton, central India. These mafic rocks are mostly dykes but there are a few volcanic exposures. Field relationships together with the petrological and geochemical characteristics of these mafic dykes divide them into two groups; Meso-Neoarchaean subalkaline mafic dykes (BD1) and Paleoproterozoic (1.88 Ga) sub-alkaline mafic dykes (BD2). The

show abstract

“…12d) can be produced by about 15 to 30% melting of the amphibolite source (cf. Rajamani et al, 1985) with variable plagioclase/ clinopyroxene/hornblende ratios. The represen tative REE composition for the shaded region (Fig.…”

Section: Partial Melting Modelmentioning

confidence: 99%

Nature and origin of lower crustal rocks of Dharmapuri area, Tamil Nadu, southern India-a goechemical approach.

1991

View full text Add to dashboard Cite

The early Proterozoic gneiss-charnockites from Dharmapuri area, southern India are investigated to understand the crustal evolution processes of the area. The granulite facies metamorphism which con verted the tonalitic gneisses to enderbites in the area was isochemical, except for the depletion of LIL elements. The enderbites of granulite zone have high K / Rb, Ba / Rb, K / U and K / Th but low U, Th, K / Sr, Rb / Sr and Th / U compared to the tonalitic gneisses of the transition zone.The petrochemical studies show a compositional continuum, without bimodal distribution pattern, from mafic gneisses to enderbites/tonalitic gneisses. Their variation suggests that the rocks were derived from igneous protoliths. The REE pattern of tonalitic rocks show LREE enrichment, HREE depletion and.variable positive Eu anomalies. The REE concentrations, however, do not show any signs of frac tionation with increasing grade of metamorphism. It is also observed that ages obtained from whole rock Rb-Sr and Sm-Nd systematics remain same, which probably suggests that the high grade metamor phism followed crustal generation processes within a short span.The protolithic orthogneisses were probably derived either by fractional crystallization of basaltic/ dioritic magma involving hornblende, plagioclase and iron oxides as the major precipitating phases, or by partial melting of an amphibolite source leaving plagioclase and clinopyroxene as the main residual phases. A fractional crystallization model is more preferred because of the presence of horn blende cumulate rocks and because there is a continuous compositional range from gabbro to granodiorite through tonalite.

show abstract

Geochemistry and Petrogenesis of Amphibolites, Kolar Schist Belt, South India: Evidence for Komatiitic Magma Derived by Low Percentages of Melting of the Mantle

Cited by 141 publications

References 0 publications

Geochemistry and petrogenesis of Neoarchaean high-Mg low-Ti mafic igneous rocks in an intracratonic setting, Central India craton: Evidence for boninite magmatism

Geochemistry and petrogenesis of Neoarchaean high-Mg low-Ti mafic igneous rocks in an intracratonic setting, Central India craton: Evidence for boninite magmatism

Sr–Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

Nature and origin of lower crustal rocks of Dharmapuri area, Tamil Nadu, southern India-a goechemical approach.

Contact Info

Product

Resources

About