Deformation of the Proterozoic Somanpalli Group, Pranhita–Godavari valley, South India—implication for a Mesoproterozoic basin inversion

Ghosh, Gautam; Saha, Dilip

doi:10.1016/s1367-9120(02)00066-4

Cited by 19 publications

(13 citation statements)

References 14 publications

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“…Rocks of the Somnur Formation are tightly folded into large asymmetric antiforms and synforms with NW-SE to NNW-SSE structural trends, marked by axial culmination and depression due to plunge reversals along the axial traces. The folds have been truncated by thrusts or transverse strike slip faults though, they can be traced for 15 to 20 km along their trend (Ghosh and Saha, 2003, their fig. 2, 2005).…”

Section: Somanpalli and Mulug Groupsmentioning

confidence: 99%

Paleogeographic and tectonic evolution of the Pranhita-Godavari Valley, Central India: a Stratigraphic perspective

Chaudhuri¹,

Deb²,

Patranabis‐Deb³

et al. 2012

American Journal of Science

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The Pranhita-Godavari Valley of central India preserves records of repeated opening and closing of Proterozoic and Gondwana rifts along the zone of NW-SE trending Neoarchean suture between the Dharwar and Bastar cratonic nuclei. The Proterozoic succession in the Valley comprises several major unconformity-bound sequences, each with a distinctive set of litho-assemblage, deposited under diverse tectonic environments with highly variable modes and tempos of sedimentation. Analysis of sedimentary attributes of unconformity-bound sequences indicates that Purana sedimentation in the Valley started with the deposition of stable platformal assemblage of carbonate-quartzarenite in an extensional sag basin. The basin opened at c. 1700 Ma. The stability of the craton was disrupted when the first major cratonic rift nucleated at c. 1620 Ma, and shortly evolved into an oceanic basin along the northeastern margin of the Valley with consanguineous deposition of a thick wedge of conglomerates, tidal sandstones and shales in the Mulug shelf, and a succession of graywacke, carbonate, siltstone-mudstone-black shale and tuff turbidites of the Somanpalli flysch in two parallel adjoining belts. The Somanpalli flysch is bounded by two shallow marine successions, analogous to several geosynclinal deposits preserved in orogenic belts, and was deposited in a deep oceanic basin along a rifted continental margin. Paleocurrent analysis reveals that siliciclastics in the flysch succession were derived primarily from a continental provenance to the southwest of the Mulug shelf, and were transported to the flysch basin across the margin. Coarse sands were deposited in large submarine fan complexes of graywackes and mixed carbonatesiliciclastics at several points. The voluminous carbonate turbidites in the flysch were also derived from the adjoining Mulug shelf. High quartz content of graywackes, their close association with tidally deposited arenites, and ocean-ward transport of sediments from cratonic hinterlands collectively attest to the deposition of the flysch in a trailing margin basin. Opening of the oceanic basin and deposition of the flysch were accompanied by extensive granulite facies metamorphism at deep crustal level indicating a genetic linkage between them, and the litho-tectonic elements were deformed into an orogenic belt during re-assembly of Dharwar and Bastar blocks. The orogenic belt girdled the northeastern margin of the PG Valley, wrapped around its southeastern corner making a syntaxial bend, and continued into the Ongole-NKSB orogenic belt which also had its peak metamorphism at c. 1600 Ma. The age of the orogeny is not well constrained, but was followed by a Neoproterozoic episode of extension, and formation of cratonic rift basin with the deposition of several thousand meters of quartz-rich sandstones of the Sullavai, Albaka and Usur sequences.

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Section: Somanpalli and Mulug Groupsmentioning

confidence: 99%

Paleogeographic and tectonic evolution of the Pranhita-Godavari Valley, Central India: a Stratigraphic perspective

Chaudhuri¹,

Deb²,

Patranabis‐Deb³

et al. 2012

American Journal of Science

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“…We suggest an analogous proposition to create a supergroup by integrating only the groups deposited in between two successive major events ( Fig. The fold -thrust deformation structures formed in the Somanpalli Group under a strong NE -SW compression (Ghosh & Saha 2003) attest to a tectonically driven basin inversion. The procedure is equivalent to the concept of a basin as a genetic unit whereby basins may be stacked one on another, rather than simply a geographical unit (Whittaker et al 1991).…”

Section: The 'Supergroup' Dilemma and Our Recommendationmentioning

confidence: 97%

“…12.2). The Somanpalli Group also records contractional deformation features similar to those of a fold-and-thrust belt (Saha 1992;Ghosh & Saha 2003, 2005. The Somanpalli Group also records contractional deformation features similar to those of a fold-and-thrust belt (Saha 1992;Ghosh & Saha 2003, 2005.…”

Section: Stratigraphy Of the Pg Valley Puranasmentioning

confidence: 99%

Chapter 12 Conflicts in stratigraphic classification of the Puranas of the Pranhita–Godavari Valley: review, recommendations and status of the ‘Penganga’ sequence

Chaudhuri¹,

Deb

Patranabis‐Deb

2015

Memoirs

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Understanding of the incompatibility of King's three-fold classification of the Proterozoic ('Purana') rocks of the Pranhita-Godavari Valley, south India, and renewed mapping and stratigraphic studies, reveal that syn-depositional basin dynamics, with differential uplift and subsidence, was the major control on basin evolution and the development of multiple unconformity-bound successions. The unconformities demarcate six major successions, the Mallampalli/Devalmari, Somanpalli, Mulug, Penganga, Albaka and Sullavai groups, each with a very distinctive set of sedimentological attributes. There are at least five different conflicting classification schemes so far. The major problems in the classification of the succession appear to lie in the recognition of unconformities and unconformity-bound successions, and in stratigraphic nomenclature. Based on field geology, available age data and the concept of the megasequence, the Mallampali, Devalmari, Mulug and Somanpalli groups have been grouped into the Pakhal Supergroup. The question of combining the rest of the groups has been deferred until the resolution of the Albaka-Penganga relationship is achieved beyond doubt. The relationships between different stratigraphic units have been critically examined to reconstruct the stratigraphic history, events of sea-level change and palaeogeographical evolution.

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“…The former developed as a shallow tidal shelf deposit and the latter was deposited in a genetically related deep water slope and continental rise environment (Chaudhuri et al, 2012). Sedimentation in the shallow wateredeep water couplet was terminated by contractional deformation (Ghosh and Saha, 2003), termed the Somanpalli orogenic belt by Chaudhuri et al (2012). The age of basin inversion is not well constrained, but we consider that it coincides with the closure of MulugeSomanpalli basin, and pre-dates deposition of the Penganga Group that overlies the Mulug Group above a major erosional unconformity.…”

Section: Cycle Imentioning

confidence: 99%

Evolving provenance in the Proterozoic Pranhita-Godavari Basin, India

Amarasinghe

Chaudhuri

Collins

et al. 2015

Geoscience Frontiers

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Deformation of the Proterozoic Somanpalli Group, Pranhita–Godavari valley, South India—implication for a Mesoproterozoic basin inversion

Cited by 19 publications

References 14 publications

Paleogeographic and tectonic evolution of the Pranhita-Godavari Valley, Central India: a Stratigraphic perspective

Paleogeographic and tectonic evolution of the Pranhita-Godavari Valley, Central India: a Stratigraphic perspective

Chapter 12 Conflicts in stratigraphic classification of the Puranas of the Pranhita–Godavari Valley: review, recommendations and status of the ‘Penganga’ sequence

Evolving provenance in the Proterozoic Pranhita-Godavari Basin, India

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