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Journal ArticleDOI

Crust–mantle interaction in the genesis of siliceous high magnesian basalts: evidence from the Early Proterozoic Dongargarh Supergroup, India

TL;DR: In this paper, the authors present chemical (XRF, INAA) and mineralogical data on a siliceous high magnesian basalts (SHMB) suite from the Early Proterozoic (2.1-2.5 Ga) Dongargarh Supergroup, Central India, the first of its kind reported from the Indian Precambrian.
About: This article is published in Chemical Geology.The article was published on 2002-07-01. It has received 27 citations till now. The article focuses on the topics: Incompatible element & Volcanic rock.
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Journal ArticleDOI
TL;DR: Based on geochemical and petrological studies of the Meso- to Neoproterozoic basic-acid rocks, a preliminary model for the formation and evolution history of the western Jiangnan orogen in the area was put forward as discussed by the authors.

184 citations

Journal ArticleDOI
01 Mar 2013-Lithos
TL;DR: The Huangshandong mafic-ultramafic intrusion is the largest in the eastern Tianshan Orogenic Belt of the CAOB and consists of a layered unit intruded by a massive unit.

67 citations


Cites background from "Crust–mantle interaction in the gen..."

  • ..., 1989), and modification of magmas through crust–mantle interaction (Sensarma et al., 2002)....

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  • ...SHMB was first reported from western Australia (Redman and Keays, 1985) and rocks derived from SHMB-like magmas have subsequently been described elsewhere in the world, mostly from the Archean–Proterozoic with a few in the Phanerozoic (Arndt and Jenner, 1986; Maier and Barnes, 2010; Seitz and Keays, 1997; Sensarma et al., 2002; Srivastava, 2006, 2008; Srivastava et al., 2010; Sun et al., 1989, 1991; Wang and Zhou, 2006)....

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Journal ArticleDOI
TL;DR: In this article, the evolution of the late Archean Belingwe greenstone belt, Zimbabwe, is discussed in relation to the geochemistry of the ultramafic to mafic volcanic rocks.
Abstract: The evolution of the late Archean Belingwe greenstone belt, Zimbabwe, is discussed in relation to the geochemistry of the ultramafic to mafic volcanic rocks. Four volcanic types (komatiite, komatiitic basalt, D-basalt and E-basalt) are distinguished in the 2� 7Ga Ngezi volcanic sequence using a combination of petrography and geochemistry. The komatiites and D-basalts are rocks in which isotopic systems and trace elements are depleted. Chemical variations in komatiites and D-basalts can be explained by fractional crystallization from the parental komatiite. In contrast, komatiitic basalts and E-basalts are siliceous and display enriched isotopic and trace element compositions. Their chemical trends are best explained by assimilation with fractional crystallization (AFC) from the primary komatiite. AFC calculations indicate that the komatiitic basalts and E-basalts are derived from komatiites contaminated with � 20% and � 30% crustal material, respectively. The volcanic stratigraphy of the Ngezi sequence, which is based on field relationships and the trace element compositions of relict clinopyroxenes, shows that the least contaminated komatiite lies between highly contaminated komatiitic basalt flows, and has limited exposure near the base of the succession. Above these flows, D- and E-basalts alternate. The komatiite appears to have erupted on the surface only in the early stages, when plume activity was high. As activity decreased with time, komatiite magmas may have stagnated to form magma chambers within the continental crust. Subsequent komatiitic magmas underwent fractional crystallization and were contaminated with crust to form D-basalts or E-basalts.

65 citations


Cites background from "Crust–mantle interaction in the gen..."

  • ...Komatiitic basalt and E-basalt Komatiitic basalts are enriched in both LREE and radiogenic isotopic compositions, and their chemical characteristics, including high SiO2 and MgO contents, are similar to those of siliceous high magnesian basalts (SHMB), which have been suggested to be derived by crustal contamination of komatiite magmas (e.g. Redman & Keays, 1985; Arndt & Jenner, 1986; Barley, 1986; Sensarma et al., 2002)....

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Journal ArticleDOI
TL;DR: In this paper, a new tectonic classification of the Bastar craton into the Western Bastar Craton (WBC), EBC, and the intervening Central Bastar Orogen (CBO) is proposed.

57 citations

Journal ArticleDOI
TL;DR: The Bastar craton has experienced many episodes of mafic magmatism during the Precambrian as discussed by the authors, and this is evidenced from a variety of precambrian volcanic and dyke formations exposed in all parts of the Bastar basin in the form of volcanics and dykes.
Abstract: The Bastar craton has experienced many episodes of mafic magmatism during the Precambrian. This is evidenced from a variety of Precambrian mafic rocks exposed in all parts of the Bastar craton in the form of volcanics and dykes. They include (i) three distinct mafic dyke swarms and a variety of mafic volcanic rocks of Precambrian age in the southern Bastar region; two sets of mafic dyke swarms are sub-alkaline tholeiitic in nature, whereas the third dyke swarm is high-Si, low-Ti and high-Mg in nature and documented as boninite-norite mafic rocks, (ii) mafic dykes of varying composition exposed in Bhanupratappur-Keskal area having dominantly high-Mg and high-Fe quartz tholeiitic compositions and rarely olivine and nepheline normative nature, (iii) four suites of Paleoproterozoic mafic dykes are recognized in and around the Chattisgarh basin comprising metadolerite, metagabbro, and metapyroxenite, Neoarchaean amphibolite dykes, Neoproterozoic younger fine-grained dolerite dykes, and Early Precambrian boninite dykes, and (iv) Dongargarh mafic volcanics, which are classified into three groups, viz. early Pitepani mafic volcanic rocks, later Sitagota and Mangikhuta mafic volcanics, and Pitepani siliceous high-magnesium basalts (SHMB). Available petrological and geochemical data on these distinct mafic rocks of the Bastar craton are summarized in this paper. Recently high precision U-Pb dates of 1891.1±0.9 Ma and 1883.0±1.4 Ma for two SE-trending mafic dykes from the BD2 (subalkaline) dyke swarm, from the southern Bastar craton have been reported. But more precise radiometric age determinations for a number of litho-units are required to establish discrete mafic magmatic episodes experienced by the craton. It is also important to note that very close geochemical similarity exist between boninite-norite suite exposed in the Bastar craton and many parts of the world. Spatial and temporal correlation suggests that such magmatism occurred globally during the Neoarchaean-Paleoproterozoic boundary. Many Archaean terrains were united as a supercontinent as Expanded Ur and Arctica at that time, and its rifting gave rise to numerous mafic dyke swarms, including boninitenorite, world-wide.

55 citations

References
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Journal ArticleDOI
TL;DR: Archean and Early Proterozoic basalts from the Kaapvaal Craton in southern Africa have geochemical characteristics of subduction-related basalts as mentioned in this paper.
Abstract: Archean and Early Proterozoic basalts from the Kaapvaal Craton in southern Africa have geochemical characteristics of subduction-related basalts. These basalts, however, cannot be produced in the subcontinental lithosphere, if ultramafic xenoliths depleted in Fe, Ti, and Ca are representative of this lithosphere. Geochemical and isotopic data are consistent with an origin by assimilation-fractional crystallization of Al-undepleted komatiite in the mid-to upper crust with Archean granitoids as the major contaminants. The proportion of granite to tonalite needed in the contaminant is higher for most of the Proterozoic basalts than it is for the Archean basalts. Widespread 2.3 Ga old within-plate, anorogenic granites in the Kaapvaal Craton may be crustal melts produced by komatiitic magmas heating the crust. Komatiitic magmatism in southern Africa could have lasted for $\geq 1600 Ma$ ($\geq 3400 to 1800 Ma$), and many Archean and Early Proterozoic within-plate basalts from other regions also may be crustally...

18 citations