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Origin of calcite by magma mixing in mingled rocks of the Ghansura Rhyolite Dome, Bathani volcano-sedimentary sequence, eastern India

Bibhuti Gogoi
Bibhuti Gogoi
 oraz 
Pallabi Basumatary
Pallabi Basumatary
   | 22 lip 2024
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Article Category: Original Paper
Data publikacji: 22 lip 2024
Zakres stron: 15 - 29
Otrzymano: 28 lut 2024
Przyjęty: 19 cze 2024
DOI: https://doi.org/10.2478/mipo-2024-0002
Słowa kluczowe
© 2024 Bibhuti Gogoi et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1.

A simplified map featuring geological and tectonic features of India and its neighbouring region (modified after Gogoi & Borah, 2023). The study area is marked by the black box. ADMB, Aravalli Delhi Mobile Belt; BC, Bastar Craton; BuC, Bundelkhand craton; BVSs, Bathani volcano-sedimentary sequence; CGGC, Chotanagpur Granite Gneiss Complex; CITZ, Central India Tectonic Zone; DC, Dharwar Craton; DV, Deccan Volcanics; EGB, Eastern Ghats Belt; KL, Kopili Lineament; MBT, Main Boundary Thrust; MCT, Main Central Thrust; MMB, Mahakoshal Mobile Belt; NSMB, North Singhbhum Mobile Belt; SB, Satpura Belt; SC, Singhbhum Craton; SONA, Son-Narmada graben; STD, South Tibetan Detachment.
A simplified map featuring geological and tectonic features of India and its neighbouring region (modified after Gogoi & Borah, 2023). The study area is marked by the black box. ADMB, Aravalli Delhi Mobile Belt; BC, Bastar Craton; BuC, Bundelkhand craton; BVSs, Bathani volcano-sedimentary sequence; CGGC, Chotanagpur Granite Gneiss Complex; CITZ, Central India Tectonic Zone; DC, Dharwar Craton; DV, Deccan Volcanics; EGB, Eastern Ghats Belt; KL, Kopili Lineament; MBT, Main Boundary Thrust; MCT, Main Central Thrust; MMB, Mahakoshal Mobile Belt; NSMB, North Singhbhum Mobile Belt; SB, Satpura Belt; SC, Singhbhum Craton; SONA, Son-Narmada graben; STD, South Tibetan Detachment.

Figure 2.

(A) Regional geological map of the BVSs illustrating different litho-units (modified after Ahmad & Paul, 2013). The GRD is marked as ‘G’ and (B) Geological map of the GRD. BVSs, Bathani volcano-sedimentary sequence; GRD, Ghansura Rhyolite Dome.
(A) Regional geological map of the BVSs illustrating different litho-units (modified after Ahmad & Paul, 2013). The GRD is marked as ‘G’ and (B) Geological map of the GRD. BVSs, Bathani volcano-sedimentary sequence; GRD, Ghansura Rhyolite Dome.

Figure 3.

Field photographs displaying (A) vesicular basalt; (B) rhyolite outcrop; and (C,D) mingled rocks with distinct mafic and felsic zones.
Field photographs displaying (A) vesicular basalt; (B) rhyolite outcrop; and (C,D) mingled rocks with distinct mafic and felsic zones.

Figure 4.

Photomicrographs displaying (A) augite phenocryst in the basaltic rocks; (B) plagioclase engulfed within augite representing ophitic texture; (C) a vesicle filled with secondary minerals chlorite and calcite in the basaltic rocks, with augite and plagioclase in the groundmass; and (D) fine-grained groundmass in the rhyolitic rocks. aug, augite; pl, plagioclase.
Photomicrographs displaying (A) augite phenocryst in the basaltic rocks; (B) plagioclase engulfed within augite representing ophitic texture; (C) a vesicle filled with secondary minerals chlorite and calcite in the basaltic rocks, with augite and plagioclase in the groundmass; and (D) fine-grained groundmass in the rhyolitic rocks. aug, augite; pl, plagioclase.

Figure 5.

Pyroxene classification diagram (after Morimoto et al., 1988). The analytical data points have been taken from already published works (Gogoi & Chauhan, 2021; Gogoi & Saikia, 2018).
Pyroxene classification diagram (after Morimoto et al., 1988). The analytical data points have been taken from already published works (Gogoi & Chauhan, 2021; Gogoi & Saikia, 2018).

Figure 6.

Photomicrographs displaying (A) contact between amphibole-rich mafic zone and fine-grained felsic zone. The interior amphiboles are pale green, while those occurring in contact with the felsic zone are dark green; (B) actinolite and hornblende-rich zones within an ARM. Unlike the actinolite-rich zone, the hornblende-rich zone consists of minerals like biotite, calcite, and ilmenite; (C) a magnified view of the actinolite and hornblende-rich zones shown in the previous image; and (D) CPL view of the previous image. act, actinolite; ARM, amphibole-rich microzones; bt, biotite; cal, calcite; CPL, crossed polarized light; hbl, hornblende; ilm, ilmenite.
Photomicrographs displaying (A) contact between amphibole-rich mafic zone and fine-grained felsic zone. The interior amphiboles are pale green, while those occurring in contact with the felsic zone are dark green; (B) actinolite and hornblende-rich zones within an ARM. Unlike the actinolite-rich zone, the hornblende-rich zone consists of minerals like biotite, calcite, and ilmenite; (C) a magnified view of the actinolite and hornblende-rich zones shown in the previous image; and (D) CPL view of the previous image. act, actinolite; ARM, amphibole-rich microzones; bt, biotite; cal, calcite; CPL, crossed polarized light; hbl, hornblende; ilm, ilmenite.

Figure 7.

Photomicrographs displaying (A,C,E) occurrence of calcite along with biotite and hornblende; and (B,D,F) CPL view of the previous image. CPL, crossed polarized light.
Photomicrographs displaying (A,C,E) occurrence of calcite along with biotite and hornblende; and (B,D,F) CPL view of the previous image. CPL, crossed polarized light.

Figure 8.

Amphibole classification diagram (Leake et al., 1997). Symbols: green plus = ARM interior amphibole, red plus = ARM exterior amphibole. ARM, amphibole-rich microzones.
Amphibole classification diagram (Leake et al., 1997). Symbols: green plus = ARM interior amphibole, red plus = ARM exterior amphibole. ARM, amphibole-rich microzones.

Figure 9.

Biotite classification diagram (Tischendorf et al., 1997).
Biotite classification diagram (Tischendorf et al., 1997).

Figure 10.

Fe-Ti oxide classification diagram.
Fe-Ti oxide classification diagram.

Figure 11.

A BSE image from the mingled rocks showing the point analyses for calcite. BSE, back-scattered electron.
A BSE image from the mingled rocks showing the point analyses for calcite. BSE, back-scattered electron.

Figure 12.

Carbonate classification diagram.
Carbonate classification diagram.

EPMA analyses of biotite from ARM in the mingled rocks of the GRD

SiO2 36.19 35.56 35.91 35.93 36.16 35.54 36.60 35.51
TiO2 1.63 1.70 1.69 1.69 1.70 1.64 1.60 1.75
Al2O3 17.75 16.30 17.06 16.91 16.83 17.58 16.91 16.45
FeO 21.16 21.27 20.92 20.95 20.92 21.25 20.54 21.44
MnO 0.26 0.30 0.16 0.13 0.17 0.20 0.19 0.17
MgO 9.20 9.21 9.33 9.15 9.26 8.81 9.35 9.12
CaO 0.11 0.02 0.08 0.10 0.10 0.09 0.08 0.03
Na2O 0.15 0.12 0.06 0.14 0.15 0.14 0.09 0.13
K2O 8.42 9.06 8.59 8.84 8.88 8.67 8.67 8.67
Cl 0.07 0.09 0.08 0.06 0.08 0.07 0.07 0.04
F 0.00 0.01 0.00 0.01 0.00 0.00 0.00 0.00
Total 94.94 93.64 93.88 93.91 94.25 93.99 94.1 93.31
Calculation based on 22 O
Si 5.55 5.58 5.57 5.59 5.60 5.52 5.65 5.58
Aliv 2.45 2.42 2.43 2.41 2.40 2.48 2.35 2.42
Sum T 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00
Alvi 0.75 0.59 0.69 0.68 0.67 0.75 0.72 0.62
Ti 0.19 0.20 0.20 0.20 0.20 0.19 0.19 0.21
Fe 2.71 2.79 2.72 2.72 2.71 2.76 2.65 2.81
Mn 0.03 0.04 0.02 0.02 0.02 0.03 0.02 0.02
Mg 2.10 2.15 2.16 2.12 2.14 2.04 2.15 2.13
Sum Y 5.79 5.78 5.79 5.74 5.74 5.77 5.74 5.80
Ca 0.02 0.00 0.01 0.02 0.02 0.01 0.01 0.01
Na 0.04 0.04 0.02 0.04 0.05 0.04 0.03 0.04
K 1.65 1.81 1.70 1.75 1.75 1.72 1.71 1.74
Sum X 1.71 1.85 1.73 1.81 1.82 1.78 1.75 1.78
Cl 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01
F 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Fe + Mg 4.81 4.94 4.87 4.84 4.85 4.80 4.80 4.95
Fe/Fe + Mg 0.56 0.56 0.56 0.56 0.56 0.57 0.55 0.57
Fe + Mn + Ti-Alvi 2.18 2.44 2.24 2.25 2.26 2.23 2.14 2.42

EPMA analyses of ilmenite from ARM in mingled rocks of the GRD

SiO2 0.10 0.05 0.75 0.02 0.33 0.49 0.64 0.06
TiO2 53.53 53.00 52.33 52.75 51.46 51.34 53.03 52.24
Al2O3 0.00 0.00 0.43 0.02 0.03 0.14 0.22 0.00
FeO 43.13 42.64 40.71 42.42 42.42 41.53 41.01 42.01
MnO 3.61 3.24 3.58 3.70 3.42 3.40 3.93 3.37
MgO 0.04 0.07 0.10 0.06 0.13 0.17 0.19 0.14
CaO 0.15 0.11 0.92 0.11 0.98 0.85 0.21 0.86
Na2O 0.02 0.04 0.02 0.02 0.03 0.02 0.01 0.00
K2O 0.04 0.08 0.00 0.20 0.08 0.03 0.24 0.02
Cr2O3 0.01 0.04 0.00 0.00 0.04 0.01 0.00 0.00
Total 100.63 99.27 98.84 99.30 98.93 97.97 99.48 98.69
The recalculated chemical composition based on an inverse spinel formula
SiO2 0.10 0.05 0.75 0.02 0.33 0.49 0.64 0.06
TiO2 53.53 53.00 52.33 52.75 51.46 51.34 53.03 52.24
Al2O3 0.00 0.00 0.43 0.02 0.03 0.14 0.22 0.00
Fe2O3 0.00 0.00 0.00 0.00 0.77 0.00 0.00 0.00
FeO 44.36 44.17 42.99 43.49 41.72 41.92 43.88 42.30
MnO 3.61 3.24 3.58 3.70 3.42 3.40 3.93 3.37
MgO 0.04 0.07 0.10 0.06 0.13 0.17 0.19 0.14
CaO 0.15 0.11 0.92 0.11 0.98 0.85 0.21 0.86
Na2O 0.02 0.04 0.02 0.02 0.03 0.02 0.01 0.00
K2O 0.04 0.08 0.00 0.20 0.08 0.03 0.24 0.02
Cr2O3 0.01 0.04 0.00 0.00 0.04 0.01 0.00 0.00
Total 101.85 100.81 101.11 100.36 99.00 98.36 102.35 98.98
Calculation based on 3 O
Si 0.00 0.00 0.02 0.00 0.01 0.01 0.02 0.00
Ti 1.01 1.01 1.00 1.01 0.98 0.99 1.01 1.00
Al 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00
Fe+3 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00
Fe+2 0.93 0.94 0.91 0.92 0.89 0.90 0.93 0.90
Mn 0.08 0.07 0.08 0.08 0.07 0.07 0.08 0.07
Mg 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01
Ca 0.00 0.00 0.02 0.00 0.03 0.02 0.01 0.02
Na 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
K 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.00
Cr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Total 2.03 2.04 2.05 2.03 2.00 2.01 2.07 2.01

EPMA analyses of amphiboles from ARM in the mingled rocks of the GRD

ARM interior amphibole ARM exterior amphibole
SiO2 51.53 54.90 53.57 54.41 52.83 53.31 54.67 53.8 43.19 49.02 49.29 50.38 46.78 47.71 48.89 0.45
TiO2 0.17 0.00 0.08 0.05 0.07 0.05 0.05 0.02 0.27 0.36 0.33 0.34 0.28 0.36 0.21 0.45
Al2O3 3.72 0.50 1.73 0.60 1.56 2.13 0.24 1.54 12.41 6.16 5.97 4.67 8.62 7.68 7.26 11.86
Cr2O3 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.05 0.00 0.07 0.04 0.06 0.08 0.03 0.07 0.00
FeO 16.56 15.86 15.05 14.11 16.32 15.76 15.47 14.86 19.09 17.70 17.33 17.5 17.91 18.3 17.94 18.37
MnO 0.40 0.51 0.41 0.42 0.40 0.43 0.53 0.36 0.38 0.52 0.41 0.49 0.33 0.45 0.49 0.29
MgO 11.93 13.84 13.27 14.05 12.75 12.95 14.04 13.70 7.19 10.48 10.69 11.19 9.23 9.54 9.95 7.62
CaO 11.70 10.94 11.90 11.96 11.95 11.65 11.30 12.01 11.50 11.61 11.52 11.24 11.53 11.24 11.14 11.53
Na2O 0.32 0.06 0.15 0.09 0.13 0.21 0.04 0.11 0.91 0.57 0.46 0.43 0.69 0.69 0.46 0.87
K2O 0.09 0.00 0.07 0.03 0.05 0.11 0.02 0.05 0.57 0.15 0.18 0.04 0.25 0.20 0.20 0.34
Total 96.42 96.61 96.23 95.72 96.07 96.60 96.36 96.50 95.51 96.64 96.22 96.34 95.70 96.20 96.61 96.33
Calculation based on 23 O
Si 7.65 8.03 7.90 8.01 7.86 7.86 8.02 7.90 6.63 7.32 7.37 7.52 7.08 7.17 7.30 6.79
Aliv 0.35 0.00 0.10 0.00 0.14 0.14 0.00 0.10 1.37 0.68 0.63 0.48 0.92 0.83 0.70 1.21
Sum T 8.00 8.03 8.00 8.01 8.00 8.00 8.02 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00
Alvi 0.30 0.09 0.20 0.10 0.14 0.23 0.04 0.17 0.87 0.40 0.42 0.34 0.61 0.53 0.57 0.90
Ti 0.02 0.00 0.01 0.01 0.01 0.01 0.01 0.00 0.03 0.04 0.04 0.04 0.03 0.04 0.02 0.05
Fe3+ 0.05 0.15 0.00 0.07 0.01 0.00 0.13 0.00 0.17 0.19 0.14 0.11 0.16 0.23 0.10 0.10
Cr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.00
Mg 2.64 3.02 2.92 3.08 2.83 2.85 3.07 3.00 1.65 2.33 2.38 2.49 2.08 2.14 2.21 1.72
Fe2+ 1.99 1.74 1.86 1.67 2.02 1.92 1.76 1.82 2.28 2.02 2.01 2.02 2.10 2.06 2.07 2.22
Mn3+ 0.00 0.00 0.02 0.05 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.01
Sum C 5.00 5.00 5.00 4.98 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00
Mg 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Fe2+ 0.01 0.04 0.00 0.00 0.01 0.02 0.02 0.01 0.00 0.00 0.02 0.06 0.01 0.01 0.06 0.00
Mn2+ 0.05 0.06 0.03 0.00 0.05 0.05 0.07 0.04 0.05 0.06 0.05 0.06 0.04 0.06 0.06 0.03
Ca 1.86 1.71 1.88 1.89 1.91 1.84 1.78 1.89 1.89 1.86 1.85 1.80 1.87 1.81 1.78 1.86
Na 0.07 0.02 0.04 0.03 0.04 0.06 0.01 0.03 0.06 0.09 0.09 0.08 0.08 0.12 0.10 0.11
Sum B 2.00 1.84 1.96 1.91 2.00 1.97 1.87 1.97 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00
Na 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.21 0.08 0.05 0.04 0.12 0.08 0.04 0.15
K 0.02 0.00 0.01 0.01 0.01 0.02 0.00 0.01 0.11 0.03 0.03 0.01 0.05 0.04 0.04 0.07
Sum A 0.03 0.00 0.01 0.01 0.01 0.02 0.00 0.01 0.32 0.11 0.08 0.05 0.17 0.12 0.08 0.21
Total 15.03 14.86 14.97 14.91 15.01 14.99 14.90 14.98 15.32 15.11 15.08 15.05 15.17 15.12 15.08 15.21
(Mg + Fe2+ + Mn2+) 4.69 4.87 4.82 4.81 4.91 4.84 4.91 4.87 3.97 4.42 4.46 4.62 4.23 4.26 4.41 3.98
Mg/Mg + Fe2+ 0.57 0.63 0.61 0.65 0.58 0.59 0.63 0.62 0.42 0.54 0.54 0.55 0.50 0.51 0.51 0.44
(Ca + Na)B 1.94 1.73 1.92 1.91 1.94 1.90 1.79 1.92 1.95 1.94 1.93 1.88 1.95 1.93 1.88 1.97
(Na + K)A 0.03 0.00 0.01 0.01 0.01 0.02 0.00 0.01 0.32 0.11 0.08 0.05 0.17 0.12 0.08 0.21

EPMA analyses of calcite from ARM in mingled rocks of the GRD

Point analysis 1/1. 1/2. 1/3. 1/4. 1/5. 1/6. 1/7. 1/8. 1/9. 1/10. 1/11. 1/12.
SiO2 0.00 0.01 0.00 0.03 0.04 3.67 0.04 0.05 0.02 0.02 0.03 0.00
TiO2 0.03 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.06 0.00 0.00 0.00
Al2O3 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.09 0.01 0.01
Cr2O3 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.02 0.00 0.03 0.00 0.00
FeO 0.71 0.81 0.75 0.71 0.69 0.46 0.59 0.74 0.58 0.88 0.67 0.61
MnO 0.61 0.81 0.55 0.71 0.63 0.40 0.67 0.65 0.53 0.73 0.52 0.64
MgO 0.22 0.25 0.27 0.18 0.20 0.17 0.19 0.21 0.20 0.20 0.18 0.21
CaO 62.85 63.89 63.09 58.71 59.24 54.71 57.73 58.41 58.06 52.38 56.2 59.45
Na2O 0.03 0.00 0.03 0.03 0.01 0.00 0.05 0.05 0.00 0.06 0.00 0.00
K2O 0.02 0.01 0.01 0.04 0.04 0.01 0.03 0.07 0.02 0.04 0.01 0.04
P2O5 0.00 0.01 0.05 0.00 0.03 0.05 0.06 0.05 0.00 0.08 0.03 0.00
BaO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
F 0.03 0.01 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.02 0.00 0.01
Cl 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.02 0.01 0.00 0.02 0.02
Total 64.52 65.84 64.79 60.41 60.90 59.49 59.37 60.27 59.47 54.55 57.66 0. 61
(Fe + Mn)CO3 2.05 2.46 2.01 2.35 2.17 1.54 2.13 2.32 1.87 2.97 2.07 2.05
CaCO3 97.61 97.16 97.57 97.35 97.50 98.15 97.55 97.33 97.79 96.66 97.62 97.60
MgCO3 0.34 0.38 0.42 0.30 0.33 0.30 0.32 0.35 0.34 0.37 0.31 0.34
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