Alkaline rocks and carbonatites of Amba Dongar and adjacent areas, Deccan Igneous Province, Gujarat, India: 1. Geology, petrography and petrochemistry

Gwalani, L.G.; Rock, N. M. S.; Chang, Wen‐Hao; Fernandez, S.; Allègre, Claude J.; Prinzhofer, Alain

doi:10.1007/bf01161569

Cited by 72 publications

(31 citation statements)

References 22 publications

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“…The surrounding area comprises basaltic lava flows intruded by alkalinecarbonatite-lamprophyre dykes and sills. This area is in close proximity to the Amba Dongar carbonatite breccia diatreme, which is a part of the Chhota Udaipur alkalinecarbonatite complex [9][10][11][12][13]. Three quartz xenocrysts-bearing dykes have been found in the area.…”

Section: Geological Backgroundmentioning

confidence: 91%

“…However, these outcrops were considered to be carbonatite breccias [14][15][16][17][18][19][20]. The outcrops near Rorda discussed here are also marked as carbonatite breccias, which is not surprising, because texture of these dykes can be easily confused with either carbonatite breccias [11,16,21] or with the basalts containing giant plagioclase phenocrysts [22], both of which occur profusely in and around the area studied. Innumerable quartz crystals and fragments ranging in size from less than a centimeter to more than 20 centimeters in length occur within fine-grained basaltic groundmass.…”

Section: Sample Descriptionmentioning

confidence: 96%

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Fluid Inclusion Study of Quartz Xenocrysts in Mafic Dykes from Kawant Area, Chhota Udaipur District, Gujarat, India

Randive

Hurai

2015

Open Geosciences

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Unusual mafic dykes occur in the proximity of the Ambadongar Carbonatite Complex, Lower Narmada Valley, Gujarat, India. The dykes contain dense population of quartz xenocrysts within the basaltic matrix metasomatised by carbonate-rich fluids. Plagioclase feldspars, relict pyroxenes, chlorite, barite, rutile, magnetite, Fe-Ti oxides and glass were identified in the basaltic matrix. Quartz xenocrysts occur in various shapes and sizes and form an intricate growth pattern with carbonates. The xenocrysts are fractured and contain several types of primary and secondary, single phase and two-phase fluid inclusions. The two-phase inclusions are dominated by aqueous liquid, whereas the monophase inclusions are composed of carbonic gas and the aqueous inclusions homogenize to liquid between 226 ∘ C and 361 ∘ C. Majority of the inclusions are secondary in origin and are therefore unrelated to the crystallization of quartz. Moreover, the inclusions have mixed carbonic-aqueous compositions that inhibit their direct correlation with the crustal or mantle fluids. The composition of dilute CO 2 -rich fluids observed in the quartz xenocrysts appear similar to those exsolved during the final stages of evolution of the Amba Dongar carbonatites. However, the carbonates are devoid of fluid inclusions and therefore their genetic relation with the quartz xenocrysts cannot be established.

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Section: Geological Backgroundmentioning

confidence: 91%

Section: Sample Descriptionmentioning

confidence: 96%

Fluid Inclusion Study of Quartz Xenocrysts in Mafic Dykes from Kawant Area, Chhota Udaipur District, Gujarat, India

Randive

Hurai

2015

Open Geosciences

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“…The stratigraphic succession of this area includes Bagh sandstone of Cretaceous age underlying the Deccan trap basaltic flows. 20,21 The Ambadungar complex is mainly characterized by alkaline silicates and carbonatites. The main alkaline rocks of this terrane are nephelinite, tinguaite, etc.…”

Section: Field Relationsmentioning

confidence: 99%

Evidence for the Contrasting Magmatic Conditions in the Petrogenesis of A-type Granites of Phenai Mata Igneous Complex: Implications for Felsic Magmatism in the Deccan Large Igneous Province

Hari

Prasanth

Swarnkar³

et al. 2018

J Indian Inst Sci

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| We report contrasting magmatic conditions in the generation of anorogenic (A-type) felsic rocks from the Phenai Mata hill of Deccan Large Igneous Province. The felsic units in the present study area can be classified as granite, monzonite, quartz monzonite and granodiorite.The field as well as the geochemical evidences collectively indicate the mixing and mingling of contrasting magma compositions which were widely involved in the genesis of these anorogenic intrusions. Based on the anorogenic granite classification diagrams, it has been observed that the granite shows A1 type character whereas the monzonite, quartz monzonite and granodiorite exhibit A2 type characters. Both A1 and A2 type intrusions were compared with the associated basaltic andesites in the variation diagrams and found that the A1 type rocks exhibit a welldefined trend pointing towards a fractional crystallization process. The A2 type rocks do not exhibit any particular geochemical relation with the mafic rocks. Moreover, the A2 type rocks are characterized by negative Nb and Ta anomalies in the normalized diagrams indicating the involvement of crustal components. From the field and geochemical evidence, it can be presumed that the A1 type rocks represent the fractional crystallization sequence from a basaltic magma, whereas the A2 rocks might have been produced by the melting of the pre-existing crust or by the assimilation of crustal components into the mafic magma during ascent.These contrasting magmas along with the mafic magma variably interacted in the shallow crustal levels to form present-day field features in the Phenai Mata Igneous complex.

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“…The flows are predominantly tholeiitic basalts. Picritic flows (MgO content ≥10%) are rare in the Western Ghats, but common in the Northwestern Deccan (Krishnamurthy and Cox, 1977;Krishnamurthy et al, 2000;Melluso et al, 2006), as are alkali basalts lamprophyres, nephelinites and carbonatites (Viladkar, 1981;Basu et al, 1993;Gwalani et al, 1993;Simonetti et al, 1995;Simonetti et al, 1998). The picritic flows from the Western Ghats have been interpreted to have originated by postemplacement olivine accumulation on the basis of field evidence, petrography, and geochemistry .…”

Section: Stratigraphy Of the Western Ghatsmentioning

confidence: 99%

“…The north-west section outcrops ~600 km away from the Western Ghats, and is composed of older alkali basalts, picrites and silica-undersaturated alkalic complexes with carbonatite and nephelinite flows and intrusives (e.g. Viladkar, 1981;Gwalani et al, 1993;Simonetti et al, 1995;Mahoney et al, 2000). Whereas the Western Ghats flows are dated at 65 Ma, the flows of the north-west section are older with ~68 Ma ages (Basu et al, 1993).…”

Section: The Deccan Trap Basaltsmentioning

confidence: 99%

Life Cycle of Deccan Trap Magma Chambers: A Crystal Scale Elemental and Strontium Isotopic Investigation

Borges¹

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Alkaline rocks and carbonatites of Amba Dongar and adjacent areas, Deccan Igneous Province, Gujarat, India: 1. Geology, petrography and petrochemistry

Cited by 72 publications

References 22 publications

Fluid Inclusion Study of Quartz Xenocrysts in Mafic Dykes from Kawant Area, Chhota Udaipur District, Gujarat, India

Fluid Inclusion Study of Quartz Xenocrysts in Mafic Dykes from Kawant Area, Chhota Udaipur District, Gujarat, India

Evidence for the Contrasting Magmatic Conditions in the Petrogenesis of A-type Granites of Phenai Mata Igneous Complex: Implications for Felsic Magmatism in the Deccan Large Igneous Province

Life Cycle of Deccan Trap Magma Chambers: A Crystal Scale Elemental and Strontium Isotopic Investigation

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