ca. 2.1 Ga Mahakoshal Supracrustal Belt: An allochthonous terrain in Central India Tectonic Zone

Lithos ◽  
2020 ◽  
Vol 374-375 ◽  
pp. 105705
Author(s):  
Tarun C. Khanna ◽  
D.V. Subba Rao ◽  
V.V. Sesha Sai ◽  
M. Satyanarayanan
Keyword(s):  
Central India ◽  
Tectonic Zone ◽  
Supracrustal Belt

∼2.1 Ga intraoceanic magmatism in the Central India Tectonic Zone: Constraints from the petrogenesis of ferropicrites in the Mahakoshal supracrustal belt

2017 ◽  
Vol 302 ◽  
pp. 1-17 ◽  
Author(s):  
Tarun C. Khanna ◽  
D.V. Subba Rao ◽  
Michael Bizimis ◽  
M. Satyanarayanan ◽  
A. Keshav Krishna ◽  
...  
Keyword(s):  
Central India ◽  
Tectonic Zone ◽  
Supracrustal Belt

Mineral chemistry, P-T pseudosection and in-situ U-Th-Pbtotal monazite geochronology of Banded Iron Formation from Bundelkhand craton North-Central India, and its geodynamic significance

2021 ◽  
Author(s):  
Mohd Baqar Raza ◽  
Pritam Nasipuri ◽  
Hifzurrahman
Keyword(s):  
Central India ◽  
Mineral Chemistry ◽  
Iron Formation ◽  
Age Group ◽  
Banded Iron Formation ◽  
Tectonic Zone ◽  
Third Age ◽  
The Third ◽  
Hydrothermal Activities

<p>The Banded Iron Formation (BIF) in Bundelkhand craton (BuC) occurred as supracrustals associated with TTG’s, amphibolites, calcsilicate rocks, and quartzite within the east-west trending Bundelkhand tectonic zone (BTZ). The BIFs near Mauranipur do not show any prominent iron-rich and silica-rich layer band and are composed of garnet, amphibole, quartz, and magnetite. The volumetrically dominant monoclinic-amphiboles are grunerite in composition. X<sub>Mg</sub> of grunerite varies between 0.39-0.37. The garnets are Mn-rich, the X<sub>Spss</sub> of garnet ranges from 0.26-0.20, X<sub>Pyp</sub> and X<sub>Grs </sub>vary between 0.10-0.06 and 0.07-0.05, respectively. P-T pseudosection analysis indicates that by destabilizing iron-silicate hydroxide phases through a series of dehydration and decarbonation reactions, amphibole and garnet stabilized in BIF at temperature 400-450°C and pressure 0.1-0.2 GPa.</p><p>Massive type BIFs have monazite grains that vary from 10 to 50 µm in size, yield three distinct U-Th-Pb<sub>total</sub> age clusters. 10-20 µm sized monazite grains yield the oldest age, 3098±95 Ma. 2478±37 Ma average age is obtained from the second group, which is relatively larger and volumetrically predominant. The third age group of Monaiztes gives an age of 2088±110 Ma. ~3100 Ma monazite suggests the older supracrustal rocks of Bundelkhand craton, similar to those obtained from Singhbhum and the Dharwar craton. The 2478±37 Ma age is constrained as the timing of metamorphism and stabilization of BuC. The third age group, 2088±110 Ma probably associated with renewed hydrothermal activities, leading to rifting and emplacement of mafic dykes in BuC.</p>

Petrogenesis and U-Pb zircon dating of Chaitma Alkaline Complex from the southern margin of the Central Indian Tectonic Zone: geodynamic implications

2021 ◽  
pp. SP513-2021-28
Author(s):  
Satya Narayana Mahapatro ◽  
M. L. Renjith ◽  
Ranjit Kumar Martha ◽  
Rakesh Kumar Patel ◽  
Dewashish Upadhyay ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magma Mixing ◽  
Central India ◽  
Alkaline Complex ◽  
Tectonic Zone ◽  
Southern Margin ◽  
Short Period ◽  
Heavy Rare Earth Elements ◽  
Central Indian Tectonic Zone

AbstractIn this study, we constrain the petrogenesis and U-Pb zircon age of a newly discovered alkaline complex, christened the Chaitma Alkaline Complex at the southern margin of the Central Indian Tectonic Zone in Central India. The Chaitma Alkaline Complex comprises syenites and gabbro, emplaced coevally and show features consistent with magma mixing. Geochemically, syenites are potassic to ultrapotassic (K2O/Na2O: 0.79-3.42) and contain high Ba (∼800 to 2700 ppm) and Sr (∼1400-3200 ppm). They show enrichment of the light rare earth elements (LREE) relative to the heavy rare earth elements (HREE) (La/Yb: 32-103) and do not display Eu-anomaly. Based on their geochemical signatures such as low MgO (<0.87 wt.%), Ni (8-16 ppm) and Cr (7-44 ppm) contents and prominent Zr-Hf negative anomaly, the syenites are inferred to have been derived by partial melting of a carbonated/metasomatised thickened lower crustal source. The coeval gabbros are undersaturated in silica (41-44 wt.%) with relatively high total alkalis (Na2O+K2O: 3.7-5.1 wt.%), Fe2O3 (17-19 wt.%), P2O5 (3.1-4.9 wt.%), Sr (1600-3400 ppm) and Ba (300-3500 ppm) contents. These have low MgO (<4.8 wt.%), Ni (13-30 ppm) and Cr (18-84 ppm). Their chemistry is interpreted to be the result of interaction with the syenitic magma. These geochemical characters along with high LREE/HREE ratio, negative trough in Nb-Ta, Zr-Hf, Ti, Sr and Rb and positive spike of Pb in spider diagram, and enrichment of LILE over HFSE indicate their derivation from metasomatised subduction modified garnet-peridotite mantle source. Our study indicates that syenites and gabbros of the Chaitma Alkaline Complex were formed from genetically unrelated parental magmas derived from distinct sources. U-Pb dating of zircon yielded magmatic emplacement age of 1626±15 Ma for the syenites. The Chaitma Alkaline Complex was presumably formed during a short period of crustal extension in the midst of a protracted period of continent-continent collision and granulite grade metamorphism (c. 1.71-1.58 Ga) at the southern margin of the Central Indian Tectonic Zone.

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