Abha Singh
University of Lucknow, Bsip, Department Member
The Kerala Basin is only onshore opportunity to study Cenozoic palaeoclimate and palaeoenvironment of southwest India encompassing Neogene global events such as Mid Miocene Climate Optimum (MMCO) and even older times of Palaeogene. The... more
The Kerala Basin is only onshore opportunity to study Cenozoic palaeoclimate and palaeoenvironment of southwest India encompassing Neogene global events such as Mid Miocene Climate Optimum (MMCO) and even older times of Palaeogene. The global warming during ~17–15 Ma (MMCO), enhanced annual surface temperature 3–4° C higher than the present, is equivalent to the warming predicted for the next century. Since the palaeogeographical and other general conditions have not been much changed from the Miocene Period, Neogene palaeoclimate of Kerala Basin can be considered as a possible analogue for future climate. Many workers have studied the Cenozoic sedimentary successions of surface and subsurface for stratigraphic classification of the rocks, but still, discrepancy persists in the chronostratigraphic relationship in sedimentary successions. The palynological investigations have also been limited mainly to palynofloral and palaeoecological inferences except a few in which palynostratigr...
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A moderately diversified, well preserved, low frequency nannofossil assemblage with over twenty species is recorded from one (S-13) calcareous marl sample of the Ariyalur Formation situated north of the village Aladi. The assemblage... more
A moderately diversified, well preserved, low frequency nannofossil assemblage with over twenty species is recorded from one (S-13) calcareous marl sample of the Ariyalur Formation situated north of the village Aladi. The assemblage includes the latest Maastrichtian index species Micula prinsii. Preservation is good and although specimens are overgrown, no dissolution effects are apparent. The assemblage is of late Maastrichtian age CC 26b (Perch-Nielsen, 1985) correlative with UC 20d TP (Burnett, 1998). The range of Micula prinsii, a low latitude marker, is indicative of the latest Maastrichtian magnetochron C20r below the K/T boundary that spans approximately the last 500,000 years of the Maastrichtian. In addition, high abundance of Petrobrasiella? bownii in both very small and large sizes (3-4 µm to 10 µm diameter) along with Ceratolithoides aculeus, C. kamptneri, Arkhangelskiella maastrichtiana, Calculites obscurus attests to this zonal placement. The high latitude Maastrichtia...
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ABSTRACT Bulletin of the Mizunami Fossil Museum, no. 39 (2013), p. 39–45, 2 figs., 1 pl. © 2013, Mizunami Fossil Museum Three species of crabs are here reported from the Lower Miocene Khari Nadi Formation at Matanomadh and Lakhpat... more
ABSTRACT Bulletin of the Mizunami Fossil Museum, no. 39 (2013), p. 39–45, 2 figs., 1 pl. © 2013, Mizunami Fossil Museum Three species of crabs are here reported from the Lower Miocene Khari Nadi Formation at Matanomadh and Lakhpat sections, Western India. Philyra karkata new species is included. Palaeocarpilius cf. P. rugifer Stoliczka, 1871 is first reported from the Middle Eocene Fulra Limestone at Lakhpat section.
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Research Interests: Landscape Ecology, Evolutionary Biology, Archaeology, Earth Sciences, Environmental Science, and 15 moreGeology, Climate Change, Landscape Archaeology, Climatology, Palynology, Ecology, Agriculture, Paleoclimate, Monsoon, Holocene, Phytolith, Evergreen, Meteorology and Climatology, Harappan Civilization, and Climate Change Culture
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A significant latest Maastrichtian calcareous nannofossil assemblage is recorded from the exposed section near Syndai Village, Meghalaya. A total of twenty two samples from sedimentary succession consisting of shales and sandy shales,... more
A significant latest Maastrichtian calcareous nannofossil assemblage is recorded from the exposed section near Syndai Village, Meghalaya. A total of twenty two samples from sedimentary succession consisting of shales and sandy shales, calcareous at places, were studied; out of which ten samples were found productive in terms of calcareous nannofossils recovery. The presence of Micula prinsii in all the productive samples along with the other latest Maastrichtian nanno taxa suggests that the assemblage belongs to Micula prinsii Zone and well correlates with the CC26b Zone of Perch Nielsen and UC20dTP Zone of Burnett which are an amalgamation of old and new biozonation schemes from a range of palaeolatitudes and biogeographic provinces from both oceanic and shelf palaeoenvironments. Micula prinsii Perch–Nielsen, the latest Maastrichtian marker all over the globe, is recorded from both deep–sea sections and shelf areas. It is most evolved form of the genus Micula and got extinct just before K–Pg boundary. The Micula prinsii Zone is marked by the first occurrence of Micula prinsii to the last occurrence of unreworked, non–survivor Cretaceous taxa.
In the present study, cluster analysis envisaged the palaeodepositional environmental changes within the Micula prinsii Zone in northeastern India. In the lower part of the section, the abundance of Micula concava and Micula staurophora with the increased numbers of Watznaueria barnesiae indicates environmentally stressful conditions with low productivity in surface water. However, in the upper part the increased numbers of Calculites obscurus with the decrease in Micula concava and Micula staurophora abundance indicates relatively increased productivity in surface water in marginal marine depositional environment.
In the present study, cluster analysis envisaged the palaeodepositional environmental changes within the Micula prinsii Zone in northeastern India. In the lower part of the section, the abundance of Micula concava and Micula staurophora with the increased numbers of Watznaueria barnesiae indicates environmentally stressful conditions with low productivity in surface water. However, in the upper part the increased numbers of Calculites obscurus with the decrease in Micula concava and Micula staurophora abundance indicates relatively increased productivity in surface water in marginal marine depositional environment.
The Kerala Basin is only onshore opportunity to study Cenozoic palaeoclimate and palaeoenvironment of southwest India encompassing Neogene global events such as Mid Miocene Climate Optimum (MMCO) and even older times of Palaeogene. The... more
The Kerala Basin is only onshore opportunity to study Cenozoic palaeoclimate and palaeoenvironment of southwest India encompassing Neogene global events such as Mid Miocene Climate Optimum (MMCO) and even older times of Palaeogene. The global warming during ~17–15 Ma (MMCO), enhanced annual surface temperature 3–4° C higher than the present, is equivalent to the warming predicted for the next century. Since the palaeogeographical and other general conditions have not been much changed from the Miocene Period, Neogene palaeoclimate of Kerala Basin can be considered as a possible analogue for future climate.
Many workers have studied the Cenozoic sedimentary successions of surface and subsurface for stratigraphic classification of the rocks, but still, discrepancy persists in the chronostratigraphic relationship in sedimentary successions. The palynological investigations have also been limited mainly to palynofloral and palaeoecological inferences except a few in which palynostratigraphy, correlation and age have been attempted on the basis of spore–pollen only. Major three Cenozones namely, Triangulorites bellus and Crassoretitriletes vanraadshooveni (Eocene–Oligocene) and Malvacearumpollis bakonyensis (Miocene) have been established. The palynological studies done in the region broadly suggest warm and humid climate with heavy rainfall. However, the recent quantitative studies have highlighted the complexity of palaeoclimatic evolution in the tropics in terms of monsoon. A time–constrained quantitative palaeovegetation and palaeoclimate reconstructions on the basis of palynology is required for evaluation of response and changes in the tropical flora of northwestern India across the major climate events. For that, the biostratigraphy of finer resolution based on systematic and integrated multi–biotic proxy is needed to establish an age model for these sedimentary successions.
Many workers have studied the Cenozoic sedimentary successions of surface and subsurface for stratigraphic classification of the rocks, but still, discrepancy persists in the chronostratigraphic relationship in sedimentary successions. The palynological investigations have also been limited mainly to palynofloral and palaeoecological inferences except a few in which palynostratigraphy, correlation and age have been attempted on the basis of spore–pollen only. Major three Cenozones namely, Triangulorites bellus and Crassoretitriletes vanraadshooveni (Eocene–Oligocene) and Malvacearumpollis bakonyensis (Miocene) have been established. The palynological studies done in the region broadly suggest warm and humid climate with heavy rainfall. However, the recent quantitative studies have highlighted the complexity of palaeoclimatic evolution in the tropics in terms of monsoon. A time–constrained quantitative palaeovegetation and palaeoclimate reconstructions on the basis of palynology is required for evaluation of response and changes in the tropical flora of northwestern India across the major climate events. For that, the biostratigraphy of finer resolution based on systematic and integrated multi–biotic proxy is needed to establish an age model for these sedimentary successions.
Present study evaluates the record of calcareous nannofossils from the deep ocean calcareous sediments recovered as drill cuttings from CLPLBarracuda G1/1 Petroleum Exploration Well drilled at Mannar Basin. The well site is 68 km away... more
Present study evaluates the record of calcareous nannofossils from the deep ocean calcareous sediments recovered as drill cuttings from CLPLBarracuda G1/1 Petroleum Exploration Well drilled at Mannar Basin. The well site is 68 km away from the North Western coastline of Sri Lanka at a latitude of 08° 20’ 34.460” N and a longitude of 79° 09’ 39.378” E. Randomly selected 20 samples were studied covering the depth from 2,145 m – 3,405 m. Each sediment sample represented a depth of 10 m.
The recorded assemblage of nannofossils was comprised of 75 species belonging to 30 genera and 20 families. In terms of both diversity and abundance of species the recorded nannofossil assemblage was well preserved and extremely productive. The presence of zonal marker taxa and other age-diagnostic species envisaged Middle Paleocene to Late Oligocene age of the 1,260 m thick well section. The absence of pentaliths indicates the existence of open marine depositional setting in the Mannar Basin during this time. The upliftment of Himalayas during the Eocene period, caused by the collision between Indian and
Eurasian lithospheric plates lead to a series of episodic intra-plate deformations which caused multiple episodes of erosion followed up by rapid deposition of terrigenous sediments in to the Bay of Bengal. Depocenteres like Cauvery and Mannar Basins, which are in close proximity to the Indian landmass, was simultaneously affected by the unexpected influx of the terrigenous sediment flow generated by those depositional events. This could have been the reason for the substantial reduction in the diversity of nannofossils recorded for the depth interval of 2,795 m – 3,405 m.
The recorded assemblage of nannofossils was comprised of 75 species belonging to 30 genera and 20 families. In terms of both diversity and abundance of species the recorded nannofossil assemblage was well preserved and extremely productive. The presence of zonal marker taxa and other age-diagnostic species envisaged Middle Paleocene to Late Oligocene age of the 1,260 m thick well section. The absence of pentaliths indicates the existence of open marine depositional setting in the Mannar Basin during this time. The upliftment of Himalayas during the Eocene period, caused by the collision between Indian and
Eurasian lithospheric plates lead to a series of episodic intra-plate deformations which caused multiple episodes of erosion followed up by rapid deposition of terrigenous sediments in to the Bay of Bengal. Depocenteres like Cauvery and Mannar Basins, which are in close proximity to the Indian landmass, was simultaneously affected by the unexpected influx of the terrigenous sediment flow generated by those depositional events. This could have been the reason for the substantial reduction in the diversity of nannofossils recorded for the depth interval of 2,795 m – 3,405 m.
The present paper deals with the record of rich and highly diversified calcareous nannofossil assemblage of Late Albian to Early Maastrichtian age from the subsurface sediments of Jaisalmer Basin, western India. The nannofossil assemblage... more
The present paper deals with the record of rich and highly diversified calcareous nannofossil assemblage of Late Albian to Early Maastrichtian age from the subsurface sediments of Jaisalmer Basin, western India. The nannofossil assemblage include, 222 species belonging to 86 genera and 22 families including 6 nannolith families which are Braarudosphaeraceae, Ceratolithaceae, Lapideacassaceae, Microrhabdulaceae, Nannoconaceae, Polycyclolithaceae and one holococcolith family Calyptrosphaeraceae. An alpha–numeric zonal scheme has been proposed in the present study which will be useful for shallow shelf areas of low latitude. 17 Zones are assigned on the presence of last occurrence (LO) of zonal markers and 5 subzones of basal most zone (TA1) are demarcated on the basis of first occurrence (FO) of subzonal markers with due nomenclature procedures.
We report here moderately diversified, fairly well-preserved calcareous nannofossil assemblage of Priabonian age comprising twenty three species from the Rewak Formation exposed along the Siju-Rewak road section, West Garo Hills,... more
We report here moderately diversified, fairly well-preserved calcareous nannofossil assemblage of Priabonian age comprising twenty three species from
the Rewak Formation exposed along the Siju-Rewak road section, West Garo Hills, Meghalaya. Out of the fifty five samples, forty seven were collected
from the lower part of the Rewak Formation and only one sample (SR 23) yielded identifiable calcareous nannofossils. Rare nannofossils occurring at few
other levels in the profile are badly preserved precluding identification. The last occurrence (LAD) of Cribrocentrum reticulatum marks the zonal boundary
between NNTe13 and NNTe14 zones of Varol (1998) in latest Priabonian (within NP21 Zone of Martini, 1971) and LAD of Pemma papillatum marks
the Priabonian/ Rupelian boundary. Presence of P. papillatum in the recovered assemblage along with the absence of C. reticulatum suggests late Eocene
(Priabonian) age corresponding with NP21 Zone of Martini (1971) and NNTe14 Zone of Varol (1998). Discoasters are absent in this assemblage. Reworking
of Late Maastrichtian and Danian age nannotaxa is also recorded.
the Rewak Formation exposed along the Siju-Rewak road section, West Garo Hills, Meghalaya. Out of the fifty five samples, forty seven were collected
from the lower part of the Rewak Formation and only one sample (SR 23) yielded identifiable calcareous nannofossils. Rare nannofossils occurring at few
other levels in the profile are badly preserved precluding identification. The last occurrence (LAD) of Cribrocentrum reticulatum marks the zonal boundary
between NNTe13 and NNTe14 zones of Varol (1998) in latest Priabonian (within NP21 Zone of Martini, 1971) and LAD of Pemma papillatum marks
the Priabonian/ Rupelian boundary. Presence of P. papillatum in the recovered assemblage along with the absence of C. reticulatum suggests late Eocene
(Priabonian) age corresponding with NP21 Zone of Martini (1971) and NNTe14 Zone of Varol (1998). Discoasters are absent in this assemblage. Reworking
of Late Maastrichtian and Danian age nannotaxa is also recorded.
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Two gymnospermous fossil woods Araucarioxylon wagadensis n. sp. and Podocarpoxylon gangtaensis n. sp. have been described for the first time from the younger part of the Gadhada formation exposed around the core of the central dome of the... more
Two gymnospermous fossil woods Araucarioxylon wagadensis n. sp. and Podocarpoxylon gangtaensis n. sp. have been described for the first time from
the younger part of the Gadhada formation exposed around the core of the central dome of the Gangta Bet. The ammonites recorded from the Gangta Bet by
earlier workers suggest that these fossil woods come from Callovian sediments forming the basal part of the succession. These fossil woods are characterized
by the presence of early and late secondary wood with small resin canals, tracheidal cells, aurocaroid or podocarpoid pits in cross field area. Dendrological
data indicate that the climate was characterized by cycles of tropical wet and dry savanna climate.
the younger part of the Gadhada formation exposed around the core of the central dome of the Gangta Bet. The ammonites recorded from the Gangta Bet by
earlier workers suggest that these fossil woods come from Callovian sediments forming the basal part of the succession. These fossil woods are characterized
by the presence of early and late secondary wood with small resin canals, tracheidal cells, aurocaroid or podocarpoid pits in cross field area. Dendrological
data indicate that the climate was characterized by cycles of tropical wet and dry savanna climate.
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A multi-proxy study involving palynology, phytoliths, sedimentology, clay mineralogy, carbon isotopes and magnetic mineralogy was carried out on Wadhwana Lake sediments from sub-humid zone of mainland Gujarat to determine the mid-Holocene... more
A multi-proxy study involving palynology, phytoliths, sedimentology, clay mineralogy, carbon isotopes and magnetic mineralogy was carried out on Wadhwana Lake sediments from sub-humid zone of mainland Gujarat to determine the mid-Holocene climatic fluctuations, and its possible impact on the Harappan culture. The 1.03 m sediment profile of Wadhwana Lake shows five paleoclimatic phases. The study reveals high lake stand during Phase I (~7500–5560 cal yr BP). A considerable cool and moist climatic condition during Phase I is inferred due to the presence of pollen belonging to wet evergreen taxa and high phytolith climatic index 'Ic'. Later part of Phase I show gradual replacement of evergreen to deciduous pollen taxa, decrease in Ic value and dominance of smectite over kaolinite, indicating a reduction in wet climatic condition due to decline in the precipitation and prevalence of seasonally dry climate. However, a large variety of Madhuca, Meliaceae, Asteraceae pollen taxa, abundant freshwater algae Chrozophora and Ceralia pollen in this period provides evidence of intensified arboriculture and agricultural activity. Low lake level and dry climate have been documented during Phase II (5560 to ~4255 cal yr BP) and are synchronous with the lake records of western Indian region. High values of phytolith aridity index Iph, high primary minerals, increase in the δ 13 C values provide evidence for excessive dry climatic conditions at ~ 4255 cal yr BP. Phase III shows a gradual strengthening of SW monsoon after ~ 3500 cal yr BP. Phase IV shows a short pulse of dry climatic conditions (~3238 to ~ 2709 cal yr BP) followed by somewhat similar to present day climate for Phase V. The study concludes that onset of dry climate after 5500 cal yr BP is a regionally spread synchronous event that has been documented in several lake records of western India. It is surmised that the urbanization in Harappan civilization in North West India was coincident with the initial phase of declining rainfall of mid-Holocene. The emergence of cultural complexity of Harappan civilization should be seen as an initial adaptation to earliest phase of environmental deterioration and its subsequent decline is probably linked with the changing seasonality pattern and excessive dry climate of later phase (~4200–4255 cal yr BP) of mid-Holocene.
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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... more
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.
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.