Tectonic Setting and Gondwana Basin Architecture in the Indian Shield

By Elsevier Science

Tectonic Setting and Gondwana Basin Architecture in the Indian Shield, Volume Four, is the newest book in the Problems and Solutions in Structural Geology and Tectonics series from Elsevier, and is a synthesized monograph on the tectonic settings of Gondwana basins of India. It is a unique book on a topic of national and international interest, especially given the economic importance of the region (coal reserves). The book is authored and edited by very experienced theoretical experts and explores and reconstructs unified stratigraphic research of the region, including the relative role of tension and lateral movement in basin formation.

Basin formation is the driving force behind formation and break-up of supercontinents and the time frame of supercontinent cycles.

• Provides the latest data on the tectonic settings of Gondwana basins of India
• Explores the unified stratigraphic research of the region
• Authored and edited by experienced theoretical experts

• Language: English
• Publisher: Elsevier Science
• Release date: Dec 4, 2018
• ISBN: 9780128152195

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work.

Chapter 1

Introduction

Subhrangsu K. Acharyya    Geological Survey of India, Kolkata, India

Department of Geological Sciences, Jadavpur University, Kolkata, India

Abstract

The Gondwana sequence in the Indian shield was initiated during the Late Paleozoic glaciation after a prolonged gap following the Proterozoic. The Gondwana sequence mainly comprises a Permian-Triassic continental succession. Similar sequence and assemblage also occur in other southern continents that are now separated by oceans but were once constituents of the Gondwana supercontinent. The Gondwana Basin belts in India occur as rectilinear zones within the Proterozoic mobile belts that have encapsuled the Archean collisional sutures. The longer boundaries of the Gondwana subbasins are generally faulted and give them half-graben geometry; their basin boundary faults indicate steep downward movement, conforming to gravity faults.

The Gondwana Basins opened possibly in response to a NNE-SSW directed extension that acted over the rigid Indian shield. Basin belts oriented obliquely at acute angles (~ 60 degrees) to the extension axis opened contemporaneously during the Late Paleozoic, mimicking the underlying Precambrian Basin in geometry facilitated by the presence of fractured basement and inheriting the Precambrian fabrics. The Late Mesozoic faulting, mafic, ultramafic intrusion and initiation of flood basalt extrusion signaled the breakup of Gondwanaland and the termination of the Gondwana geodynamic cycle.

Keywords

Control of pre-Gondwana basement structures; Extensional rift basin; Gondwanaland; Inherited Precambrian fabrics; Supercontinent

In geology, the name Gondwana was introduced by H. B. Medlicott in 1872 in a manuscript report on the ancient kingdom of Dravidian Gonds in Central India. The Gondwana sequence comprises a continental succession with coal seams and the remains of fossil plants and animals. A parallel group of continental formations with much the same lithologic and organic contents were soon discovered from several parts of the Southern Hemisphere. The distantly located continents, with the characteristic Gondwana flora and fauna, either formed parts of one unbroken continental tract, or there must have been land connections in the southern world for a long succession of periods, which permitted unrestricted migression of the animals and plants between the continental confines. Thus, according to Prof. Von Huene, there is extraordinary resemblance between the dinosaurs of Madhya Pradesh in India and those of Madagascar, Brazil, Uruguay, and Argentina. Edward Suess used the term Gondwanaland in 1885 to refer to this southern supercontinent, which was separated from the large northern continent, Laurasia, by the equatorial sea Tethys (Fig. 1.1). The fragmentation of these two primeval continents through drifting was propounded by Wegener in 1915, when the first edition of The Origin of Continents and Oceans, a book outlining Wegener's theory, was published; expanded editions were published in 1920, 1922, and 1929. The concept of continental drift was elaborated further by du Toit (1937), and subsequently explained by plate tectonics (Veevers, 2004; Blakey, 2008).

Fig. 1.1 Configuration of Gondwanaland and Laurasia separated by the Tethys Sea of the Panthlasa Ocean.

The Gondwana supercontinent, or Gondwanaland (Veevers, 2004), has been subdivided into two parts, East and West, each of which have contrasting histories (Unrug, 1996). The East was fragmented from the older Rodinia supercontinent, assembled toward the end of the Mesoproterozoic global orogeny. It survived the breakup of Rodinia during the Neoproterozoic and remained essentially coherent until the Mesozoic fragmentation of Gondwana. The Indian continent is a fragment of East Gondwana. West Gondwana, in contrast, consisted of a number of the Archaean-Paleoproterozoic (2500–1600 Ma) cratons assembled during the Pan-African Brasiliano orogeny (660–590 Ma) (Fig. 1.2). The Gondwana supercontinent, comprising present-day South America, South Africa, India, Australia, and Antarctica, is characterized by several common continental characteristics. The climatic variation within Gondwana is explained primarily due to sequential movement of Gondwanaland across the south rotational pole. Improved paleomagnetic measurements from different Gondwana continents lend support to this belief. Paleogeography during the latest Carboniferous and Early Permian corresponds to the Gondwana glaciations and initiation of the Gondwana Basin formation in India. There was common development of intracratonic sedimentary basins of coal-bearing sediments, followed by the common presence of red beds with reptilian remains, which are known as the Gondwana Basins. A large eruption of continental flood basalt signaled the breakup of the Gondwanic Indian continent from South Africa via Madagascar and Australia. Following a long hiatus after the Proterozoic, Gondwana succession in India accumulated in a number of discrete linear basin belts mainly covering the Permian to the Triassic period. Broad cumulative thickness of the Gondwana sediments in different basins is shown in Fig. 1.3. However, this does not take into account the extent of erosion and thus, does not provide actual information about tectonic depth achieved by the different basins. The distribution of Gondwana Basins within the Indian shield is shown in Fig. 1.4, which also shows the location of the Gondwana Basin of the Darjeeling Himalayan foothills. Coal-bearing rocks continue to occur along the foothills of Bhutan to Arunachal Pradesh. The distribution of Gondwana Basin belts and amalgamated subbasins in the Indian shield is shown in Fig. 1.5. Belt-wise, briefly summarized stratigraphy is also depicted in the diagram.

Fig. 1.2 East-West Gondwana blocks. After Unrug, R., 1996. The assembly of Gondwana supercontinent: contrasting histories of east and west Gondwana. Gondwana 9, vol. 2, pp. 989–1002.

Fig. 1.3 Stratigraphic thickness of the Gondwana sequence and its constituent formations and groups in the Indian subcontinent.

Fig. 1.4 Layout of the Gondwana coal fields and the Gondwana Basin belts.

Fig. 1.5 Layout of the Gondwana Basins, basin belts, and subbasins in the Indian shield. Some major faults and locations of the Early Permian marine beds shown. KMG-1 bore hole records presence of Early Permian microfauna. Abbreviated Gondwana Basins: A , Auranga; AG , Athgarh; B , Bokaro; D , Daltonganj; H , Hutar, H-A , Hasdo-Arand; IB , Ib, J , Jainti; KN , Karanpur North; KS , Karanpura South; R , Raniganj; RM , Ramgarh; RW , Rewa; S , Singrauli; SG , Shohagpur; ST , Satpura; T , Talcher.

The development of these intracratonic basins is typically controlled and bounded by faults that followed the Precambrian mobile belts and lineaments. These were reactivated during the filling of the Gondwana Basins. The basin fill also indicates fault-controlled subsidence and sedimenation. The pattern of the intrabasinal faults and their relationships with the respective basin-bounding faults reflect basin evolution that occurred mainly under extension. There was preferential subsidence in locations of differently oriented, preexisting discontinuities in the Precambrian basement that developed as the Gondwana Basins on the Indian subcontinent with variable, but mutually compatible, (Acharyya and Mukhopadhyay, 2014) kinematics during a bulk extension of the Indian Precambrian basement shield. These discontinuities are grossly oriented along the present-day NE-SW to N-S direction and evolved as extensional basins.

Some researchers also invoked the role of E-W and WNE-ESE trending strike-slip movements that were restricted to narrow zones close to the Son-Narmada South megafault zone and Damodar Valley Basins (Fig. 1.5; cf., Chakraborty and Ghosh, 2005; Chakraborty et al., 2003). The kinematic disparity of the individual basins may have resulted due to different relative orientations of the basement discontinuities.

References*

Acharyya S.K., Mukhopadhyay G. Coal and Lignite Basins of India: Development, Resource, and Multidimensional Utilisation Perspective. Bangalore: Geological Society of India; 2014.168.

Blakey I.R. Godwana paleogeography from assembly to breakup a 500 m.y. odyssey. Geol. Soc. Amer. Sp. Paper. 2008;441:1–28.

Chakraborty C., Ghosh S.K. Pull-apart origin of the Satpura Gondwana basin, central India. J. Earth Syst. Sci. 2005;114:259–273.

Chakraborty C., Mandal N., Ghosh S.K. Kinematics of the Gondwana basins of peninsular India. Tectonophysics. 2003;377:299–324.

du Toit A. Our Wandering Continents. Edinburgh, London 1937.xiii 336.

Unrug R. In: The assembly of Gondwana supercontinent: contrasting histories of East and West Gondwana. 9th International Gondwana Symposium; 989–1002. 1996;vol. 9 2.

Veevers J.J. Gondwanaland from 650–500 Ma assembly through 320 Ma mergers in Pangea to 185–100 Ma breakup: supercontinental tectonics via stratigraphy and radiometric dating. Earth Sci. Rev. 2004;68:1–132.

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* To view the full reference list for the book, click here

Chapter 2

Regional Tectonism and Gondwana Stratigraphy

Subhrangsu K. Acharyya    Geological Survey of India, Kolkata, India

Department of Geological Sciences, Jadavpur University, Kolkata, India

Abstract

Basal glaciogene tilloid and coal seam-bearing Lower Gondwana sequence is characterized by the Glossopteris flora, whereas feldspar-poor, variegated claystone-bearing and hill-forming cover sequence characterized by the Ptilophylum flora represent unconformable Upper Gondwana cover. A transition zone comprises lingering Glossopteris with the advent of Dicroidium flora and reptilian fauna and common presence of red beds. The Gondwana sedimentation initiated during the Late Paleozoic icehouse state and continuing up to the Mesozoic greenhouse state provides an additional climate-influenced correlation tool. The Kamthi unit is ill-defined based on mixed litho- and biostratigraphic characters. It may be only used in an informal sense.

At the Rangit valley Sikkim, clastic muscovite from coal-bearing Barakar Formation arkose has yielded Cambro-Ordovician Ar-Ar age, which is inferred to have been provenanced from a proto-Himalayan granitoid area located to the north of the Gondwana rift basins of the Indian shield.

Keywords

Gondwanaland; Gondwana time slot; Greenhouse state; Icehouse state; Informal unit Kamthi; Kamthi problem; Northern provenance; Supercontinent; Gondwana classification

Introduction

The Gondwana basins in the Indian shield preserve a thick sedimentary pile that was deposited for nearly over 200 million years from the latest Carboniferous to the Early Cretaceous. However, there is a lack of well-constrained age data for most of its formations, which causes both intra- and interbasinal correlation problems, particularly for the Mesozoic formations. The Indian Gondwana sequence can be broadly structured to a composite sequence of four representative lithostratigraphic units, for example, the glaciogene Talchir, the carbonaceous shale, coal-bearing Damuda, the feldspathic sandstone and red claystone-bearing Panchet and its equivalents, and the hill-forming feldspar-poor, quartz-arenite and variegated claystone-bearing Mahadeva equivalents, or the Supra-Panchet. These lithostratigraphic units, for brevity, were designated as Units A through D by Dutta et al. (2015). Each of these lithostratigraphic units corresponds to an informal formation or group rank. The setting of the Kamthi formation is, however, different, as it assumes mixed bio- and lithostratigraphic levels of Late Permian to Early Jurassic dual features as will be discussed later.

Out of three primary factors that control the nature of the Gondwana sediments, two factors are broadly common: they are mainly derived from granitic rocks, and they are deposited largely in the fluvial nature of basin fill. Thus these two factors, granitic provenance and broadly fluvial environment, remained somewhat similar for Gondwana sediments.

Except for the lower most glaciogene, fluvioglacial, glaciomarine sediments in the lithostratigraphic Unit A, the rest of the Gondwana succession is largely under a variety of fluvial settings, with some records of fluviodeltaic, fluviolacustrine, and alluvial sediments.

The Gondwana sedimentation broadly coincided with the global climatic cycle as it was changing from an icehouse state in the Late Paleozoic to the greenhouse state in the Mesozoic. The influence of changing climate over the sequential development of the lithostratigraphic units also provided an additional correlation tool (Dutta et al., 2015). With each broad change in climate, accompanied by subtle changes in environment, intensity of tectonism, particularly reactivation of the Precambrian faults and shear zones in the basement, determined the nature of the successive sedimentary units in the Gondwana basins. A pronounced unconformity separates the Supra-Panchet and its equivalents from three underlying lithostratigraphic units. Excluding coastal Gondwana, Unit D, represented by hill-forming feldspar-poor, quartz-arenite and variegated claystones, indicating products of deep chemical weathering, is classified as the Upper Gondwana, whereas the remaining A-C lithounits are considered the Lower Gondwana.

2.1 Gondwana Time Slots I–VII

There are distinct spatial and temporal similarities in lithological, faunal, and floral distribution in the different Gondwana basins of the southern continents, including India. Some events recognized from other parts of Gondwanaland, like marine flooding surfaces, large-scale tectonism, or major changes in the depositional environment have been used as a tool for regional temporal correlation within and across the Gondwana basins of the Indian continent. The total time span of deposition in the Gondwana basin has been classified into seven time slots (Mukhopadhyay et al., 2010). This approach has also been followed here to correlate reginal tectonic episodes and time slots in the Gondwana stratigraphy (Table 2.1).

Table 2.1

2.2 Time Slot I: Gzhelian 302 Ma

Veevers (2006) has considered 302 Ma (Gzhelian) to be the time of inception of the Gondwana sedimentation. Deglaciation caused a rise in the sea level and seawater inundated the basins deep inside Gondwanaland, superposed with the influence of local tectonism providing broad linearity to the courses of marine transgressions (Fig. 2.1). Thus, the Eurydesma-bearing and other cold water marine fauna and microbiota of marine affinity invaded interior parts of Gondwanaland during Asselian/Early Sakmarian around 290 ± 4 Ma (Bangert et al., 1999). The top of Time Slot I has been designated to be 290 Ma, which corresponds to the top of the Talchir Formation in India. Time Slot I ranges from around 302 Ma (Gzhelian Stage) to 290 Ma (Asselian-Early Sakmarian Stages), during which time, this early glacial or glacially influenced sedimentation took place. Marine fossils, dominated by a Eurydesma-bearing assemblage of pelecypods, brachiopods, bryozoa, foraminenifera have been recorded from Talchir Formation from many basins/localities like Umaria, Manendragarh, Shahpur, Daltonganj, as well as from the Rajasthan shelf, and nearly all along the Eastern Lesser Himalayas and all along the Tethyan Himalayan margin (Sastry et al., 1977 and references therein; Ranga Rao et al., 1979; Acharyya, 1979, unpublished data; Ghosh, 2003a,b). Sporadic occurrences of various marine biota, palynomorph, and of Early Permian affinity are also reported from Gondwana basins like Raniganj, Bokaro, Rajmahal, Jharia, and Ramgarh, as well as from the East Coast of Athgarh, Palar (Venkatachala and Rawat, 1973; Tiwari et al., 1981; Rawat and Jain, 1985; Ghosh et al., 1987; Chaudhuri and Mondal, 1989; Pal et al., 1996). The top of the Talchir Formation can reasonably be correlated to the Gondwana-wide transgressive event of Time Slot I and assigned an Asselian/Early Sakmarian age (290 Ma).

Fig. 2.1 Likely pathways of Early Permian marine incursions to the Indian shield. Marine incursions generally spread as embayments. Abbreviated localities: BD , Badhaura; D , Daltonganj; DM , Damodar Valley; M , Manendragarh; KM , Khemgaon, Sikkim; R , Raniganj; Su , Subansiri; TN , Tindharia; U , Umaria. Suggested location of northern provenance to the Gondwana rift basins of the Indian shield shown.

The fossil assemblage from Manendragarh, Daltonganj, and Shahpur, as well as those from the Wak area in the Rangit Valley, Sikkim, the Tindharia area, Darjeeling foothills, are similar and rich in Eurydesma, while those of Umaria, Badhaura, and marine Permian beds from Arunachal Praadesh foothills are characterized by Stepanoviela and other brachiopod fauna, but also containing Eurydesma (Acharyya et al., 1979). Sastry and Shah (1964) postulated two transgression pathways, one from the east via Rangit Valley Gondwana and other from the west via the Narmada-Son lineament/Umaria. On the other hand, Acharyya (2004) proposed contemporaneous transgressions from both east and west. However, considering the wide imprints of marine signature in the Talchir Formation, marine Talchir along the East Coast belt, and in the lower parts of the Barakar from several Gondwana basins, it is also likely that a major marine trough that existed between India and Australo-Antractica possibly had intermittent connection with Tethys and to Early Gondwana basins of the Eastern Indian shield (Fig. 2.1; Mukhopadhyay et al., 2010).

Following the Sakmarian marine transgression, a near-shore environment prevailed in many basins of Gondwanaland with the advent of a fluvial to estuarine environment in the marginal part of the basins under the periglacial climate (Collinson, 1996; Chakraborty et al., 2003b; Eyles et al., 2003; Acharyya and Mukhopadhyay, 2014). The lower part of the Barakar or the Karharbari stratigraphic units in India can be equated with the deposits during Time Slot II. Fluvial/estuarine conditions prevailed in smaller basins and in marginal parts of larger basins with the deposition of coarse clastics with coal that have often been designated as the Karharbari unit (Raja Rao, 1987). Coal seams in the Karharbari unit are better preserved in smaller subsidiary basins like the Giridih and Daltonganj basins north of the main Damodar Valley belt, and in Talcher, Bisrampur basins of the Mahanadi Valley (Figs. 1.4 and 1.5). Besides subtle lithological distinction, this zone has distinct floral and palynological character (Gondwanidium, Buriadia-bearing flora and Palynozone II of Tiwari, 1996), which is quite similar to those in the underlying Talchir but distinctly different from those in the overlying Barakar. In several Gondwana basins, the Karharbari unit is overlain by a thick oligomictic quartzite or pebbly quartzite beds; elsewhere, the contact is conformable in appearance. The Karharbari unit is, thus, proposed to represent a biostratigraphic zone in a lithofacies within the Barakar Formation (refer to status of the Karharbari unit for more information in Chapter 14).

During the Late Carboniferous, Gondwanaland rotated clockwise, and thus, the setting of the eastern Indo-Australian and northern Greater Indian margin changed from the equatorial to high southern paleolatitudes. There was, thus, widespread glaciomarine and rift-related sedimentation, locally associated with volcanic rocks during the Early Permian along the Greater Indo-Australian northern margin of the supercontinent that also contained parts of southeast Asia (Acharyya, 1979, 1996, 1998; Chang and Pan, 1984; Chen and Xie, 1994; Bunopas and Vella, 1984; Metcalfe 1991; Fan and Zhang, 1994). These facies and faunal assemblages are typically absent from the Indochina-East Malaysia and the South and North Chinese blocks, which were equatorially located.

A major rift phase affected the northern Indo-Australian margin during the Early Mid-Permian, when the Lhasa and the Changtang Tibetan blocks, the Sibumasu (Siam-Burma-Malaysia-Sumatra) block, as well as the Cimmerian block, as proposed by Sengör (1985), were rifted and drifted apart, consequently opening up the South Tethys. The Late Paleozoic glaciomarine and rift-generated pebbly mudstone and diamictite were deposited along extensive areas in the Himalayan belt and over these blocks, which were associated with the presence of cold water marine fauna and with or without the remains of the Glossopteris and the South Cathaysian flora. During the Late Permian, the Sibumasu block was accreted to the Indochina-East Malaysian block (Acharyya, 1998, 2000b; Acharyya and Mukhopadhyay, 2014).

The Permo-Carboniferous diamictite and volcaniclastics-bearing, narrow, tectonized, but laterally persistent, sediments of Gondwana affinity are exposed intermittently all along the Eastern Himalaya from the Darjeeling foothills, West Bengal, and the Rangit Window in West Sikkim (about 15 km north of Darjeeling basin Fig. 1.4) and further east to the Kameng and Siang districts, and the foothills of Arunachal Pradesh across Bhutan (Acharyya, 1979, 1996, unpublished data). Similar Permian Gondwana equivalent paralic to shallow marine sediments that are locally associated with volcanic rocks and volcaniclastics are also recorded from several other sections of the Lesser and Tethyan Himalayan belts (Acharyya et al., 1979). The thick and abruptly varying thickness of the Late Paleozoic diamictites, containing exclusively local clasts, their association with volcanic rocks, their nature, and their rare association with alkaline mafic rocks indicate that the Early Permian glaciomarine sedimentation along both what are now the southern and northern Himalayan belts was under the influence of failed rift activity (Acharyya, 1996, 1998; Vanney and Spring, 1993; Bose et al.,