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1. Archean Polymetamorphism in the Central Dharwar Craton, Southern India.

Author

Kaempf, Jonas, Clark, Chris, Johnson, Tim E., Jayananda, Mudlappa, Alfing, Julian, Payne, Justin, Sajeev, Krishnan, and Hand, Martin

Subjects
GEOLOGICAL time scales, NEOARCHAEAN, METAMORPHIC rocks, GARNET, PHASE equilibrium, GRANULITE
Abstract

Petrochronological investigations of granulite‐facies metapelitic rocks from the eastern contact of the Closepet granite in the Central Dharwar Craton (CDC), southern India, provide new pressure–temperature–age (P–T–t) constraints on two seemingly discrete Archean metamorphic events during the Neoarchean and late Paleoarchean eras. Phase equilibrium modelling and conventional thermobarometry coupled with in situ monazite and garnet geochronology constrain Neoarchean (ultrahigh‐temperature; UHT) metamorphic peak conditions to ~930 °C and ~6.7 kbar at c. 2.63 Ga, then cooling and limited decompression to ~5.7 kbar at ≤810 °C. Monazite inclusions in garnet least affected by Neoarchean recrystallisation have distinct positive Eu anomalies and yield ages of c. 3.2 Ga, whereas garnet cores interpreted to have grown at the same time have slightly younger apparent ages of c. 3.1 Ga. We interpret this age mismatch to be the result of extensive resorption of garnet during Neoarchean UHT metamorphism, which led to widespread modification of the initial Lu–Hf systematics in garnet to produce younger apparent ages. The effect of retention and inward intracrystalline diffusion of Lu on the isotopic composition of garnet is most pronounced close to the resorbed grain margins and decreases towards the core, as reflected by progressively younger apparent single‐spot garnet dates from core to rim. Despite extensive overprinting of the sample at c. 2.63 Ga, the trace element composition of Paleoarchean monazite indicates growth in equilibrium with garnet but in the absence of feldspar, which is predicted to occur over a broad stability range at P ≥ 8 kbar and T ≤ 700 °C. Such P–T conditions are uncommon in the metamorphic rock record prior to the Neoarchean, but are typical of Barrovian‐type metamorphism, which is considered to be an expression of accretionary‐to‐collisional orogenesis. Rocks of similar age and metamorphic grade have been reported from the core of the Western Dharwar Craton (WDC) and may reflect regional subduction at the margins of the CDC and WDC since the late Paleoarchean. Neoarchean UHT metamorphism in the Dharwar Craton is coeval with a cluster of other UHT occurrences at 2.7–2.6 Ga, indicating the existence of globally elevated thermal gradients at that time. [ABSTRACT FROM AUTHOR]

Published
2025
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9. Three-dimensional field perspective on deformation, flow, and growth of the lower continental crust (Dharwar craton, India)

Author

Chardon, Dominique and Jayananda, Mudlappa

Subjects
India -- Natural history, Cratons -- Structure, Geology, Structural -- Research, Rock deformation -- Models, Earth -- Crust, Earth -- Structure, Earth sciences
Abstract

[1] The study of fabric development and juvenile batholith emplacement across the tilted crustal section of the Eastern Dharwar craton shows that horizontal, constrictional deformation affected large volumes of the midcrust and lower crust at the time of regional partial melting and magmatic accretion. Constriction is achieved by a combination of coeval shallow and steep planar fabrics sharing a common horizontal elongation direction, two sets of conjugate strike-slip shears, and extensional shear zones. The Eastern Dharwar craton illustrates an end-member deformation mode by which a particularly weakened lithosphere responds to shortening by developing distributed, horizontal plane strain on a crustal scale, resulting from the combination of crustal shortening and lateral gravity-driven flow. Thinning accompanying constrictional deformation is interpreted as compensating for juvenile magmatic accretion and thickening of greenstone belts and as acting to maintain a stable crustal thickness. Such a midcrustal to lower crustal deformation process may provide a resolution of the batholithic room problem in a softened crust submitted to lateral shortening and may explain nearly isobaric retrograde pressuretemperature-time paths of high temperature--low pressure high-grade terrains. Citation: Chardon, D., and M. Jayananda (2008), Three-dimensional field perspective on deformation, flow, and growth of the lower continental crust (Dharwar craton, India), Tectonics, 27, TC1014, doi:10.1029/ 2007TC002120.

Published
2008

15. Reconstruction of Post-Deccan topographies from mapping of relict lateritic paleosurfaces: Implications for long-term denudation of Peninsular India

Author

Jean, Amandine, Beauvais, Anicet, Chardon, Dominique, Bonnet, Nicolas, Jayananda, Mudlappa, Janwari, Shazia, Mathe, P.-E., Aix Marseille Université (AMU), Institut de Recherche pour le Développement (IRD), Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), University of Hyderabad, and Centre for Earth and Space Sciences [Hyderabad]

Subjects
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Cenozoic topographic rejuvenation of divergent continental margins and their cratonic hinterland is a matter ofdebate. For instance, continental scale tilt has been advocated as a cause of Late Cenozoic relief growth of theIndian Peninsula. Our work aims at providing independent geomorphological constraints to test such assertions.The western margin of the Peninsula bears theWestern Ghats Escarpment (WGE), which carves both Precambrianrocks and 65 Ma old Deccan Traps. The escarpment separates a narrow coastal lowland plain drained to the ArabianSea from a highland plateau drained towards the Bengal Sea. Alternating and coupled chemical weatheringand erosion led to formation and dissection of lateritic paleolandscapes preserved both sides of the WGE. In thehighland, the relicts of three distinctive lateritic surfaces are recognized. They formed successively from 53Ma to 23 Ma on the basis of ages obtained by Ar-Ar dating of K-rich manganese oxides [1]. The first surfaceis topped by a duricrust rich in Al (bauxite) forming mesas at altitudes of 960 to 1400 m. The second surfacecalled "Intermediate" is mantled by a ferricrete, whose relicts remain 100 m below the bauxite at altitudes of 850 to 1250 m. The third surface corresponds to the relicts of a lateritic pediment, which may be capped by aferricrete at altitudes of 600 to 900 m. Three lateritic surfaces have been documented in the lowland. The Ar-Arages obtained indicate common lateritic weathering in both the highland and the lowland between at 53-45 Ma,then a divergence later on [1]. The oldest remnants of lateritic surface in the lowland are preserved at maximumelevation of 400-500 m close to the WGE and correspond to a pediment. This ancient landform was re-altered at24-19 Ma to form residual hills of the “Intermediate” relief (ca. 350-200 m). A younger pediment formed aroundthe residual hills and is preserved at ca. 150-50 m elevation.Relicts’ elevations of the three surfaces have been retrieved in both the lowland and the highland to reconstructsuccessive topographies across the WGE and estimate relief evolution and erosion budgets for major time steps.The results suggest that the denudation did not exceed 10 m/my in the Highland since 45 Ma, and is less than 11m/my since mitigation of chemical weathering ca. 23 Ma ago. In the lowland, denudation was limited to 5 m/mysince 45 Ma and less than 6 m/my since 19 Ma, implying negligible reworking of the WGE, which stabilizedat least 50 Ma ago [2]. These results have major implications for relief evolution of South India. They implyvery low relief growth since the Eocene and do not require a tilt of the Peninsula. They further put constraints onsedimentary supplies to both margins of the Peninsula over the last 50 Ma.[1] Bonnet et al., 2016, Chemical Geology 446, 33-53.[2] Beauvais et al., 2016, Geology 44, 299-302.

Published
2017
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16. Regolith and landscape evolution in Peninsular India and West Africa: Morphoclimatic evolution of the two continents over the Cenozoic

Author

BEAUVAIS, Anicet, Chardon, D, Jean, A, Jayananda, Mudlappa, Shazia, Janwary, Bonnet, Nicolas, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Centre for Earth and Space Sciences [Hyderabad], University of Hyderabad, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; Shields’ surfaces of the tropical belt have been continuously shaped over the Cenozoic under thecombined or alternating effects of chemical weathering and mechanical erosion that left steppedrelict lateritic paleolandsurfaces exposing different generations and type of regolith in today’ssceneries. These lateritic paleolandscape remnants are well preserved in West Africa and in highlandPeninsular India, particularly on Deccan Traps. The stepped character of such paleolandscaperemnants allows to describing a common geomorphic sequence of three successive sub-continentalscale lateritic paleolandsurfaces on the two sub regions. The first surface is defined by the oldestremnants, which are generally topped by Al-Fe (mostly bauxitic) lateritic duricrusts upon distant kmscalemesas or as larger provinces on high relictual topographic massifs (e.g., Fouta Djalon in WestAfrica or Nilgiri hills in South India). The relict bauxitic landforms generally dominate from less thanca. 300 m the relicts of a second geomorphic level (so-called “intermediate” surface), which ismantled by ferruginous lateritic duricrusts. The third and last paleolandsurface remnants lie less thanca. 400 m below the bauxitic landforms, and consist in a weathered lateritic pediment that is locallycapped by a ferricrete.The ages of these continental-scale lateritic paleolandsurfaces may be bracketed using 40Ar/39Ardating of K-Mn oxides (cryptomelane) formed in their underlying weathering profiles in the Africanand Indian contexts [1,2,3]. The first surface is Eocene and correlates with the Eocene climaticoptimum (ca. 50 Ma) that is recorded throughout the tropical belt by the production of bauxite. InSouth India, the Intermediate surface has evolved by dominant chemical weathering since the LateEocene (ca. 37 Ma) and records peak weathering activity in the Late Oligocene. In West Africa, thatpaleolandsurface seems to have only record the late Oligocene interval (ca. 29-24 Ma) of intenseweathering. Abandonment of the Intermediate landscape as a result of its dissection by the rivernetwork took place in the Latest Oligocene on both continents. By contrast, the later pedimentseems to have been shaped quite rapidly (ca. 32-29 Ma) and was weathered around the Oligocene-Miocene boundary (ca. 29-24 Ma) in India, whereas it took longer to form (ca. 24-18 Ma) and wasweathered mostly during the Mid-Miocene (ca. 18-11 Ma) in West Africa. The contrasts in themorphoclimatic record of the two sub regions are linked to the spatial diversification of climaticregimes after the Eocene climatic optimum. However, the combination of the ages with the elevationdifferences between each lateritic paleolandsurface documents denudation rates with comparableand very low amplitudes (5-15 m/m.y.) in these two continents over the last 50 Ma.[1] Beauvais A and Chardon D (2013) Geochem Geophys Geosyst 14:1590-1608, doi:10.1002/ggge.20093.[2] Bonnet NJ et al. (2014) Earth Planet Sci Lett 386:126-137, doi:10.1016/j.epsl.2013.11.002[3] Bonnet NJ et al. (2016) Chem Geol, in press.

Published
2016

17. Conference Reports

Author

Peter Königshof, E. Schindler, V. Wilde, J. Lazauskiene, M. Namik Yalçin, Wouter Bleeker, Jayananda Mudlappa, Talat Ahmad, Yury L. Voytekhovsky, V. M. Tiwari, Leila M. Gonzales, Boris Natalin, Jacques Charvet, Reiner Klemd, Afia Akhtar, R.H. Sawkar, and Eirini Theodosiou

Subjects
General Earth and Planetary Sciences
Published
2010
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18. Chromian spinel compositions from Madawara ultramafics, Bundelkhand Craton: Implications on petrogenesis and tectonic evolution of the southern part of Bundelkhand Craton, Central India.

Author

Mohanty, Niranjan, Singh, Surya Pratap, Satyanarayanan, Manavalan, Jayananda, Mudlappa, Korakoppa, Madiwalappa Mallappa, Hiloidari, Sikha, and Chalapathi Rao, N.V.

Subjects
CHROMITE, ORTHOPYROXENE, PETROGENESIS, GEOCHEMISTRY, DIORITE, MAGNETITE
Abstract

Madawara ultramafic complex (MUC) in the southern part of Bundelkhand Craton, Central India comprises peridotite, olivine pyroxenite, pyroxenite, gabbro, and diorite. Coarse‐grained olivine, clinopyroxene (Cpx), amphibole (Amp), Al‐chromite, Fe‐chromite, and magnetite with rare orthopyroxene (Opx) are common minerals in peridotite. Chromites are usually coarse‐grained euhedral found as disseminated crystals in the olivine matrix showing both homogeneous and zoned texture. Al‐chromite, primarily characterizes Cr‐spinels and its subsequent fluid activity and alteration can result in the formation of Fe‐chromite, chrome magnetite, and magnetite. Mineral chemistry data suggest that Al‐chromite is characterized by moderately high Cr2O3 (38.16–51.52 wt.%) and Fe2O3 (3.22–14.51 wt.%) and low Al2O3 (10.63–21.87 wt.%), MgO (1.71–4.92 wt.%), and TiO2 (0.22–0.67 wt.%), whereas the homogeneous Fe‐chromite type is characterized by high Fe2O3 (25.54–47.60 wt.%), moderately low Cr2O3 (19.56–37.90 wt.%), and very low Al2O3 (0.06–1.53 wt.%). Subsequent alteration of Al‐chromite and Fe‐chromite leads to formation of Cr‐magnetite and magnetite. The Cr# of Al‐chromite varies from 55.12 to 76.48 and γFe3+# from 8 to 19, whereas the ferrian chromite has high Cr# varying from 94.27 to 99.53 while its γFe3+# varies from 38 to 70. As a whole, the primary Al‐chromite shows low Al2O3, TiO2 contents, and high Fe#, Cr# values. Olivines have forsterite ranging from 75.96% to 77.59%. The bulk‐rock geochemistry shows continental arc geochemical affinities indicated by the high concentration of large‐ion lithophile elements and U, Th relative to the low concentration of high‐field strength elements. These petrological and mineralogical as well as primary Al‐chromite compositions plotted in different discrimination diagrams suggest an arc environment that is similar to Alaskan‐type intrusion. [ABSTRACT FROM AUTHOR]

Published
2019
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21. Lateral constrictional flow of hot orogenic crust: Insights from the Neoarchean of south India, geological and geophysical implications for orogenic plateaux

Author

Chardon, Dominique, Jayananda, Mudlappa, Peucat, Jean-Jacques, Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Department of Geology, University of Dehli, Terre, Temps, Traçage, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS)

Subjects
Archean, hot orogen, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, seismic reflectivity, Dharwar craton, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], crustal flow, Tibet
Abstract

International audience; This study provides an in situ geological perspective on fabrics produced by synconvergence lateral crustal flow of hot orogens. It is based on the example of the Neoarchean orogen of the Dharwar craton (India) and combines structural analysis and ion microprobe U!Pb zircon geochronology. We document a pervasive, three!dimensional flow mode of the lower crust, called lateral constrictional flow (LCF), which combines orogen!normal shortening, lateral constrictional stretching, and transtension. LCF achieves gravity!driven flow, lateral escape, and 3!D mass redistribution in a viscous lower crust submitted to convergence. LCF tends to mechanically and thermally homogenize the lower crust and efficiently compensates topographic relief at a shallow level in the crust. Three type!geodynamic contexts are envisaged for LCF: plateau interiors, inner parts of collisional crustal wedges or plateau edges, and throughout wide ultrahot orogens such as the Neaoarchean orogen of south India. LCF makes the lower crust act as a strain gauge between lateral gravitational collapse or tectonic thickening of the upper crust, thrust stacking in the lowermost crust (collisional crustal wedge case), crustal shortening, and/or lateral flow of the upper mantle. In the case of plateau interiors or ultrahot orogens, LCF of a thick lower crust enables coupling of upper crustal deformation with upper mantle flow through a hot and thin lithosphere being shortened coherently. LCF generates a subhorizontal lamination that should produce the strong seismic reflectivity and lateral anisotropy of the Tibetan Plateau and a variety of hot orogens.

Published
2011
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22. Precambrian continental strain and shear zone patterns: South Indian case

Author

Chardon, Dominique, Jayananda, Mudlappa, Chetty, Talari, Peucat, Jean-Jacques, Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Department of Geology, Bangalore University, National Geophysical Research Institute India, National Geophysical Research Institute, Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Geophysical Research Institute [Hyderabad] (NGRI), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Kinematics of crustal and mantle deformation, Regional crustal structure, Asia, Continental tectonics, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Precambrian
Abstract

International audience; This study addresses the tectonic and mechanical significance of crustal-scale strain and shear zone patterns in the South Indian Precambrian lithosphere. It is based on a tectonic map of the Dharwar craton derived from LANDSAT imagery, existing documentation, and our own field observations. We document the contrasted responses of the two main parts of the craton to late Archean (2.56­2.51 Ga) shortening. The old (>3 Ga) lithosphere of the Western Dharwar craton stabilized at 2.61 Ga underwent moderate shortening and strain localization along spaced shear zones. The Eastern Dharwar craton, rejuvenated by late Archean juvenile magmatic accretion, responded to shortening by flowing laterally against the Western Dharwar craton. Shortening operated without significant thickening because of the high buoyancy of the juvenile crust and the very low strength of its mantle lithosphere. The late Archean crustal-scale shear zone network did not accommodate large displacements and only contributed to smoothing out of strain heterogeneities during the latest stages of flow. The shear zone pattern only reflects the symmetry of the regional finite strain field of a wide hot orogen. It does not result from terrain amalgamation but accompanies crustal flow and does not compare with those of modern active margins, which accommodate unidirectional transpression. Our analysis further suggests that the shear zones bounding the craton did not record large horizontal displacements during final assembly of Gondwana but rather transverse shortening and vertical extrusion.

Published
2008
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23. Evidence in Archaean Alkali Feldspar Megacrysts for High-Temperature Interaction with Mantle Fluids

Author

Słaby, Ewa, primary, Martin, Hervé, additional, Hamada, Morihisa, additional, Śmigielski, Michał, additional, Domonik, Andrzej, additional, Götze, Jens, additional, Hoefs, Jochen, additional, Hałas, Stanisław, additional, Simon, Klaus, additional, Devidal, Jean-Luc, additional, Moyen, Jean-François, additional, and Jayananda, Mudlappa, additional

Published
2011
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24. Archean granite-greenstone tectonics at Kolar (South India): Interplay of diapirism and bulk inhomogeneous contraction during juvenile magmatic accretion

Author

Chardon, D, Peucat, J-J, Jayananda, Mudlappa, Choukroune, P, Fanning, Christopher, Chardon, D, Peucat, J-J, Jayananda, Mudlappa, Choukroune, P, and Fanning, Christopher

Abstract

The structural study of the Kolar greenstone belt and surrounding granite-gneiss terrains combined with U-Pb dating reveals that the middle and lower crustal tectonoplutonic pattern of the eastern Dharwar craton developed during a major magmatic accretion event between 2550 and 2530 Ma. The granite-greenstone pattern resulted from the interference of gravity-driven sagging of the greenstones (i.e., diapirism), E-W bulk inhomogeneous shortening combined with horizontal N-S stretching, and syntectonic juvenile pluton emplacement. Bulk inhomogeneous contraction is accommodated by the synchronous development of a pervasive, N-S trending vertical foliation, shallow stretching lineation, and conjugate strike-slip shear zone pattern within and outside the greenstone belt, resulting in regional horizontal pure shear deformation. The plutons around the greenstone belt record regional contraction by developing one set of strike-slip C-S fabrics of the shear zone pattern. The development of the granite-greenstone pattern was coeval and compatible with deformation during juvenile magmatic accretion, melting, and granulite metamorphism in the lower crust. The Kolar example points to a specific crustal rheology that allowed sagduction of the greenstones and regional distributed bulk inhomogeneous strain, due to mechanical homogeneity and low viscosity provided by large-scale melting during the accretion event. This example further suggests specific boundary conditions to the craton that allowed E-W inhomogeneous shortening to be accommodated by N-S stretching and spreading of the crust without significant tectonic thickening. Such tectonoplutonic pattern is specific to the Archean and may develop as a consequence of mantle plume activity in intracontinental settings.

Published
2002

25. Archean granite-greenstone tectonics at Kolar (South India): interplay of diapirism and bulk inhomogeneous contraction during juvenile magmatic accretion

Author

Chardon, Dominique, Peucat, Jean-Jacques, Jayananda, Mudlappa, Choukroune, Pierre, and Fanning, C. Mark

Subjects
Kolar, India -- Natural history, Cratons -- Natural history, Earth sciences
Abstract

[1] The structural study of the Kolar greenstone belt and surrounding granite-gneiss terrains combined with U-Pb dating reveals that the middle and lower crustal tectonoplutonic pattern of the eastern Dharwar craton developed during a major magmatic accretion event between 2550 and 2530 Ma. The granite-greenstone pattern resulted from the interference of gravity-driven sagging of the greenstones (i.e., diapirism), E-W bulk inhomogeneous shortening combined with horizontal N-S stretching, and syntectonic juvenile pluton emplacement. Bulk inhomogeneous contraction is accommodated by the synchronous development of a pervasive, N-S trending vertical foliation, shallow stretching lineation, and conjugate strike-slip shear zone pattern within and outside the greenstone belt, resulting in regional horizontal pure shear deformation. The plutons around the greenstone belt record regional contraction by developing one set of strike-slip C-S fabrics of the shear zone pattern. The development of the granite-greenstone pattern was coeval and compatible with deformation during juvenile magmatic accretion, melting, and granulite metamorphism in the lower crust. The Kolar example points to a specific crustal rheology that allowed sagduction of the greenstones and regional distributed bulk inhomogeneous strain, due to mechanical homogeneity and low viscosity provided by largescale melting during the accretion event. This example further suggests specific boundary conditions to the craton that allowed E-W inhomogeneous shortening to be accommodated by N-S stretching and spreading of the crust without significant tectonic thickening. Such tectonoplutonic pattern is specific to the Archean and may develop as a consequence of mantle plume activity in intracontinental settings. INDEX TERMS: 8110 Tectonophysics: Continental tectonics--general (0905); 8099 Structural Geology: General or miscellaneous; 9619 Information Related to Geologic Time: Precambrian; 8035 Structural Geology: Pluton emplacement; 8199 Tectonophysics: General or miscellaneous; KEYWORDS: greenstone belt, continental deformation, pluton emplacement, granulite, shear zones

Published
2002

29. Very long-term stability of passive margin escarpment constrained by 40Ar/39Ar dating of K-Mn oxides.

Author

Beauvais, Anicet, Bonnet, Nicolas J., Chardon, Dominique, Arnaud, Nicolas, and Jayananda, Mudlappa

Subjects
*ARGON-argon dating, *MANGANESE ores, *ORE deposits, *LATERITE, *MANGANESE oxides, *CLIFFS, *CHEMICAL denudation
Abstract

The post-rift denudation history of high-elevation divergent continental margins is central to deciphering source-to-sink systems across such margins and to unraveling their topographic evolution. We performed 40Ar-39Ar dating of supergene K-Mn oxides from supergene manganese ore deposits in order to constrain the age of in situ formed laterites on both the lowland and highland sides of the Western Ghats Escarpment of Peninsular India. Documentation of laterites as old as 53 Ma on the highland and 47 Ma at the foot of the escarpment shows that the escarpment stabilized before 47 Ma (possibly 60 Ma). The topographic setting of the dated weathering mantles also constrains denudation of the lowland and the highland since ca. 50 Ma to maximums of 5 m/m.y. and 15 m/m.y., respectively. Our results challenge denudation rates derived from apatite fission track thermochronology by documenting the topography and relief longevity of the southwest Indian margin and its hinterland. The results preclude large-magnitude uplift of Peninsular India after the Eocene, and more generally argue against late Neogene uplift and topographic rejuvenation of continental shields. [ABSTRACT FROM AUTHOR]

Published
2016
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