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Tectonic geomorphology and neotectonic setting of the seismically active South Wagad Fault (SWF), Western India, using field and GPR data

Maurya D. C., Chowksey V., Tiwari P., Chamyal L. S.

Acta Geophysica

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2017

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Vol. 65, no. 6

1167--1184

EN

The South Wagad Fault (SWF) is an E–W trending fault that delimits the Wagad uplift comprising Mesozoic rocks in its northern upthrown block and Neogene–Quaternary sediments in the southern downthrown block. Detailed GPR investigations were carried out at seven sites selected after field studies. All profiles clearly showed the lithological contrast across the fault. The sharp amplitude contrast of the radar waves along a vertical to sub-vertical line is interpreted as the near surface trace of the SWF. As the Quaternary sediments are not displaced, we infer that no large magnitude earthquake has occurred along the SWF in late Quaternary. We attribute the low magnitude of neotectonic activity along the SWF to gentle warping of the Tertiary rocks in the southern downthrown block and greater accumulation of compressive stresses along the nearby KMF with an opposite structural setting. This is consistent with the observed variable levels of ongoing seismicity in the region around the SWF.

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Sedimentological and palaeoecological significance of the trace fossils of the Jurassic rocks of the Jhura Dome, Mainland Kachchh, western India

Patel S. J., Patel N. J.

Volumina Jurassica

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2015

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Vol. 13, no. 2

101--139

EN

The Middle to Late Jurassic succession of the Jhura Dome (Jhurio and Jumara formations) of the Mainland Kachchh, western India, comprises a ~500 m thick succession of clastic carbonates and mixed siliciclastic-carbonates, intercalated with shales. The sequence, as based on sedimentological characteristics, exhibits six sedimentary facies and four subfacies. Certain exceptional bands of the ripplemarked calcareous sandstone, shale and oolitic limestone facies are rich in ammonites, belemnites, brachiopods and bivalves. Thirty four ichnogenera were also identified and analysed paleoecologically. These trace fossils represent five ethological categories and six ichnoassemblages. Seventeen ichnoguilds are demonstrated based on space utilization for characterising the ecological complexity of ichnoassemblages. Bathymetric control of the trace fossils resulted with development of Skolithos, Cruziana and Zoophycos ichnofacies type conditions. The sedimentological and ichnological data analysis revealed seven distinctive depositional regimes ranging from offshore shelf below storm wave base to middle shoreface.

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Integrated biostratigraphy of the Jurassic strata of the Wagad Uplift, Kachchh, western India

Rai J., Garg S., Gupta M., Singh A., Pandey D. K., Fürsich F. T., Alberti M., Garg R.

Volumina Jurassica

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2015

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Vol. 13, no. 2

55--80

EN

An integrated study based on calcareous nannofossils, organic-walled dinoflagellate cysts, and ammonites from the Washtawa and Kanthkot formations of the Wagad Uplift have allowed a detailed documentation of the stratigraphic position of these formations within the Oxfordian and Kimmeridgian sediments of the Kachchh Basin, western India. The nannofossil assemblages from the lower part of the Nara Shale Member exposed in the Nara and Washtawa domes, the Kanthkot Ammonite Beds along the Trambau River section, and the Patasar Shale Member exposed along the Trambau River section and the Patasar Tank section in the eastern part of the Wagad Uplift belong to the NJ 14 Cyclagelosphaera margerelli Zone of the Early Oxfordian, the NJ 15a Lotharingius sigillatus Zone of the Middle Oxfordian, and the NJ 15b Cretarhabdus conicus of Early Kimmeridgian age, respectively. Zonation schemes, based on calcareous nannofossils, dinoflagellate cysts, and ammonites were calibrated highlighting their biostratigraphic potential. These studies may represent a reference biochronology for Oxfordian–Kimmeridgian age strata applicable to the Tethyan realm of which India was a part during Late Jurassic times.

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Ichnology of mixed siliciclastic-carbonate sedimentary cycles and their sequence stratigraphic context: Kaladongar Formation (Middle Jurassic) of Kachchh, western India

Joseph J. K., Patel S. J.

Volumina Jurassica

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2015

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Vol. 13, no. 2

81--99

EN

The Middle Jurassic Kaladongar Formation, Patcham Island, Kachchh, western India, comprises of a 353 m-thick mixed siliciclastic-carbonate succession of asymmetrical shallowing and deepening upward sedimentary cycles. It is subdivided into five main facies i.e., micritic sandstone, allochemic sandstone, sandy allochem limestone, micritic mudrock, and sandy micrite along with shales and conglomerates. Eight trace fossil assemblages comprising 34 ichnogenera are defined, including the Asterosoma, Gyrochorte, Rhizocorallium, Thalassinoides, Planolites–Palaeophycus, Phycodes, Ophiomorpha, and Skolithos assemblages that reflect five depositional facies: offshore, transitional, lower, middle, and upper shoreface. The sedimentary packages and associated trace fossil assemblages are separated by various discontinuities, stratigraphic surfaces and stratigraphic boundaries within the succession of the Kaladongar Formation and reveal three phases of regression (RST-I, RST-II and RST-III) and three phases of transgression (TST-II, III and IV) within the 3rd order systems tracts developed in the slowly transgressing sea during the Bajocian-Bathonian time interval.

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Facies and diagenetic evolution of the Bathonian-Oxfordian mixed siliciclastic-carbonate sediments of the Habo Dome, Kachchh Basin, India

Ahmad A. H. M., Irshad R., Bhat G. M.

Volumina Jurassica

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2015

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Vol. 13, no. 1

83--104

EN

This paper examines the depositional environment and diagenetic aspects of the exposed Patcham and Chari formation within the Habo Dome. The Patcham Formation is represented by the Black Limestone Member. The Chari Formation is represented by two distinct sedimentary successions: (i) shale and carbonates, and (ii) coarse clastics. The paper describes eleven lithofacies from these successions. The depositional framework constituents of these facies have been greatly modified by diagenetic evolution through time. Two main depositional environments, i.e. foreshore intertidal and shoreface (subtidal), have dominated during their deposition. The diagenetic signatures observed within these sediments suggest early or syndepositional changes in marine phreatic and burial environments. Two phases of early mechanical compaction have largely governed porosity evolution within the limestone facies. Micritization of the allochems was caused by endolithic algae prevalent within the restricted lagoon environments with stagnant marine phreatic zone conditions. Random dissolution of microcrystalline grains has created vugs with patchy distribution reflecting neomorphism within the meteoric vadose zone. The types of cements within the sandstone facies include silica, calcite, and its replacement by Fe-calcite cement. The sandstones were deposited in a relatively low energy environment below storm wave base. The depositional conditions have controlled the early diagenesis of the sandstones which in turn have influenced their burial diagenesis.

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Ammonites from the Oxfordian-Kimmeridgian boundary and the Lower–Upper Kimmeridgian of Kachchh, western India

Pandey D., Alberti M., Fürsich F., Głowniak E., Olóriz F.

Volumina Jurassica

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2013

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Vol. 11, no. 1

97–-146

EN

Several new specimens of ammonites from the Oxfordian and Kimmeridgian of Kachchh, western India, are described and illustrated. The Oxfordian ammonites ?Subdiscosphinctes Malinowska, Perisphinctes Waagen, Dichotomoceras Buckman, and ?Larcheria Tintant, all from Bharodia in the Wagad Uplift, enable tentative biochronostratigraphic correlations with the uppermost Middle Oxfordian up to the lower Upper Oxfordian of the unified Submediterranean zonation, whereas the Kimmeridgian ammonites Streblites Hyatt, “Orthosphinctes” Schindewolf, Torquatisphinctes Spath, Pachysphinctes Dietrich, Katroliceras Spath, Aspidoceras Zittel, and Schaireria Checa reconfirm a stratigraphic gap embracing incompletely known parts of the uppermost Oxfordian and the Lower Kimmeridgian as known from the ammonite records of the Kachchh Mainland of the Kachchh Basin.

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Optical dating of sediments in Khari River basin and slip rate along Katrol Hill Fault (KHF), Kachchh, India

Kundu H. K., Thakkar M. G., Biswas R. H.

Geochronometria

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2010

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Vol. 37

21-28

EN

In the central region of Mainland Kachchh, Western India, the Katrol Hill Fault (KHF) is one of the major E-W trending faults. An understanding of the episodes of reactivation during the past has a bearing on the future seismicity in the region. These reactivations are manifested by offset of elevation of fluvial sediments and scarp-derived colluvium in the Khari River basin, SE of Bharasar (23°11'36.5"N, 69°35'22.6"E). Stratigraphic offsets of the sediments at this site suggest three episodes of reactivation of the KHF during the late Quaternary. Optical dating of samples from sediment strata and top layer of scarp-derived colluvium using Natural Sensitivity Corrected – Single Aliquot Regenerative (NCF-SAR) protocol suggested that these events occurred during the past ~30 ka, with the most recent historic episode around 3.0 ka. Given that a part of the slip recorded in the form of sediments offset, was lost due to erosion after faulting, a lower bound to the time averaged slip rate of the segment of KHF, is inferred to be > 0.23 mm/a during the past 30 ka.

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Ammonoid zonation in the Oxfordian of the Gondwanian Tethyan margin developed in Kachchh, India

Krishna J., Pandey B., Ojha J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

181-181

EN

The Kachchh Basin in the extreme west of India has been considered the most prospective region of the Gondwanian Tethyan margin for the development of an independent Jurassic ammonoid zonal framework. In furtherance of our earlier realizations of independent ammonoid zonal schemes in the Kachchh of Callovian, Kimmeridgian and Tithonian stages, we here present the ammonoid zonal formulation in the Kachchh Oxfordian into a succession of 7 zones that is exclusively developed in Perisphinctidae. The older 3 zones (Bernensis Zone, Obliqueplicatum Zone, and Indogermanus Zone) are developed in the Lakhapur section in the distal exposed part of the basin with good density, diversity and frequency of ammonoids. The 4th zone – the Orientalis Zone which includes the 1st order MFS (maximum flooding surface) is the richest in ammonoids of the entire Kachchh Jurassic in the proximal most exposed part of the basin at Kantkote. The younger 3 zones (Subevolutum Zone, Kantkotensis Zone, and Wagurensis Zone) also developed in the Kantkote-Bharodia section in the proximal exposed part are ammonoid scarce in view of their location on the margin along with stratigraphic position above the 1st order MFS. All the Kachchh Oxfordian 7 zones are precisely correlated with the European Tethyan standard on the basis of common or similar Peltoceratinae (Peltoceratoides in Early and Gregoryceras in the Middle Oxfordian), Perisphinchinae (Properisphinctes and Alligaticeras in Early, Perisphinctes and Larcheria in Middle, Dichotomoceras in early Late, and Pseudorthosphinctes, Orthosphinctes and Idoceras in late Late Oxfordian). The geologically interesting and eventful Kachchh Oxfordian includes the 1st order MFS of the Toarcian-Albian sequence in the younger part of the late Middle Oxfordian Orientalis Zone (equivalent of the European Transversarium Zone, Schilli Subzone, Subschilli Horizon), which subdivides the Kachchh Oxfordian into two altogether contrasting sedimentation regimes with markedly revealing litho-biofacies and environmental frameworks. The Early and Middle Oxfordian until the close of Schilli Subzone time is in extremely slow sedimented, condensed to starved, fining, thinning and deepening upward in irregularly based, lensoidal, pebbly/nodular/conglomeratic, hard grounded, mixed carbonate-siliclastic ammonoid rich facies with increase in the share of carbonates and also in the reworking of pebbles/nodules. There is decrease in clastics, also in presence and size of physical structures and energy framework from margin to basin as also upward. Paleontologically, there is increase in the ammonoid density, diversity and frequency, share of European Tethyan elements, also of relatively deeper water sphaeroceratids, phylloceratids, lytoceratids upward and also from margin to the basin. In contrast, from the start of Rotoides Subzone time to near the close of Oxfordian, the ca 280 m thick sedimentary succession present only in the margin in relatively rapidly sedimented, coarsening, thickening and shallowing upward, is scarce to nearly devoid of ammonoids and other macro-invertebrates.