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1. Laevigatosporites major, TBW-15.8-2-G31-1, 2. Murospora florida, TBW-15.8-2-V34-1, 3. Densoisporites velatus, TBW-13-3-V39-2, 4. Densoisporites velatus, TBW-13-4-H35-1, 5. Contignisporites cooksoniae, TBW-15.8-3-V29-2 (distal view), 6. Contignisporites cooksoniae, TBW-15.8-3-V29-2 (proximal view), 7. Contignisporites glebulentus, TBW-01-08-6-S64-2, 8. Contignisporites crenatus, TBW-01-08-6-N48-2, 9. Matonisporites dubius, TBW-1-1-W43-1, 10. Foveosporites canalis, TBW-1-1-X38-2, 11. Cicatricosisporites hughesii, TBW-01-08-6-J49-2, 12. Cicatricosisporites ludbrooki, TBW-01-08-6-J64-3, 13. Cicatricosisporites purbeckensis, TBW-13-3-N34-2, 14. Unidentified trilete spore, TBW-15.8-2-R30-1, 15. Dictyotosporites complex, TBW-01-08-6-X47-4, 16. Aequitriradites verrucosus, TBW-13-3-L34, 17. Retitriletes facetus, TBW-01-08-6-R39-4, 18. Cyathidites australis, TBW-13-3-P35-1, 19. Neoraistrickia truncatus, TBW-13-4-V34-1, 20. Cyathidites australis, TBW-01-08-6-S64-4.
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The palynological study of the Tabbowa sediments from Sri Lanka reveals predominant Jurassic gymnospermous pollen assemblage (Araucariacites australis, A. cooksonii, A. fissus and Callialasporites dampieri with spore Murospora florida) belongs to the Callovian-Kimmeridgian age. The collective palynoflora can be correlated to the Classopollis–Arauca...
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... Two hundred (200) palynomorphs were counted from each sample to capture a considerable variation of the palynomorphs. On the basis of recovered percentages of palynomorphs, palynoassemblages were identified. The palynofacies were allocated after observing the relative percentages and counting over 300 organic matter particles in each sample. Figs. 4 and 5 represent the well-preserved and stratigraphically significant palynomorphs and its quantitative distributions are shown in Fig. 6. Recovered palynofacies and their quantitative Table 1 Geological Time Scale with reference to major geological formations of Sri Lanka from the Paleozoic to present (after Cooray, 1984 ...
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... However, most of the paleo studies in the Indian subcontinent focus on post-breakup and dispersal events, based on the Indian Ocean floor sediments and magnetic anomalies (Bandara et al. 2020;Kularathna et al. 2020;Ratnayake 2021a). Prerift sedimentary archives in the drifted Gondwana fragments (e.g., Sri Lanka, Madagascar, and Seychelles) can be used to reconstruct the Jurassic paleoclimate in the Gondwana supercontinent (Weerakoon et al. 2019(Weerakoon et al. , 2021. The global Jurassic climate was significantly different from modern conditions and is considered a long-time greenhouse climate with minimum equatorto-pole thermal gradients and high atmospheric CO 2 levels ranging from 1200 to 3000 ppmv (Retallack 2001;Dromart et al. 2003). ...
... The limitedage sedimentary rocks from the Jurassic, Miocene, and Quaternary periods cover about 10% of the landmass (Cooray 1984(Cooray , 1994. Andigama and Tabbowa are Jurassic sedimentary basins and the Tabbowa Basin is more deeply buried than the Andigama Basin based on palynostratigraphy and palynofacies (Weerakoon et al. 2019). The faulted Andigama Basin is located in the northwest of the country (Fig. 1a), and this basin is filled with Gondwana sedimentary rocks on the Precambrian metamorphic basement (Tantrigoda and Geekiyanage 1991;Ratnayake and Sampei 2015). ...
The Andigama Basin is a pre-rift Gondwana sedimentary basin containing Late Jurassic to Early Cretaceous calcareous sandstones and carbonaceous shales of varying thickness. This study aims to reconstruct the weathering, tectonic setting, and paleoenvironment of East Gondwanaland using a 90 m deep drill core. Whole-rock geochemistry and elemental analysis were carried out using X-ray fluorescence spectrometry and CHNS/O elemental analyzer, respectively. Lithological changes in the borehole core reflect diverse hydrodynamic conditions. X-ray diffraction patterns indicate a significantly high content of quartz and kaolinite peaks. Scanning electron microscope images suggest that quartz, carbonate, and aluminosilicate dominant detrital particles and chemical residues enhanced the cementation by reducing the porosity and permeability of sealing interfaces. Major oxide and trace element concentrations are approximately similar to the Upper Continental Crust values. High Chemical Index of Alteration, Plagioclase Index of Alteration, Index of Compositional Variability, and high content of kaolinite peaks reflect intense chemical weathering, suggesting a hot and humid climate during the Late Jurassic–Early Cretaceous periods. The calculated paleo-land surface temperature (24.7 ± 5 °C) and mean annual precipitation (1120 mm) values are also consistent with the interpretation of weathering indices and global oxygen isotopic studies. Provenance and tectonic setting discrimination diagrams suggest the deposition of quartzose and mafic igneous sources under the passive margin stage. In addition, elemental analysis indicates a nutrient-rich (average total organic carbon = 4.67 ± 1.04 wt. % and total nitrogen = 3.13 ± 3.39 wt. %) and oxic to oxygen-poor reducing (average total sulfur = 2.13 ± 1.43 wt. %) swamp environment. Consequently, the Late Jurassic–Early Cretaceous climate was simulated as a prominent deglaciation/hot and humid climate in the Gondwana supercontinent, based on calculated paleo-land surface temperatures and mean annual precipitation.
... The study and interpretation of palaeoenvironment and palaeodepositional settings in the Gondwana basins have long been a challenge. Nowadays, palynofacies and palynofloral distribution of organic matter have been used for the palaeodepositional settings and organic sedimentary facies (Aggarwal et al. 2019;Götz et al. 2017). The integrated approach of the palynoflora along with the palynofacies has become one of the reliable proxies in the palaeoenvironmental reconstruction to enhance the understanding of the process and factors responsible for the Gondwana sedimentation (Götz et al. 2017;Weerakoon et al. 2019). ...
... Nowadays, palynofacies and palynofloral distribution of organic matter have been used for the palaeodepositional settings and organic sedimentary facies (Aggarwal et al. 2019;Götz et al. 2017). The integrated approach of the palynoflora along with the palynofacies has become one of the reliable proxies in the palaeoenvironmental reconstruction to enhance the understanding of the process and factors responsible for the Gondwana sedimentation (Götz et al. 2017;Weerakoon et al. 2019). Additionally, palynofacies (palynomorphs, plant tissues, cuticles, wood, opaque/translucent phytoclasts, degraded organic matter, amorphous organic matter) analysis also demonstrates source rock provenance, proximal and distal trend, oxic and anoxic environments, sequence biostratigraphy, etc. (Tyson 1995;Götz et al. 2003;Oboh-Ikuenobe et al. 2005;Closas et al. 2005;Cazzulo-Klepzig et al. 2009;Hermann et al. 2012;Wheeler and Götz 2017;Prasad et al. 2013;Aggarwal et al. 2019). ...
... The integrated approach of the palynoflora along with the palynofacies has become one of the reliable proxies in the palaeoenvironmental reconstruction to enhance the understanding of the process and factors responsible for the Gondwana sedimentation (Götz et al. 2017;Weerakoon et al. 2019). Additionally, palynofacies (palynomorphs, plant tissues, cuticles, wood, opaque/translucent phytoclasts, degraded organic matter, amorphous organic matter) analysis also demonstrates source rock provenance, proximal and distal trend, oxic and anoxic environments, sequence biostratigraphy, etc. (Tyson 1995;Götz et al. 2003;Oboh-Ikuenobe et al. 2005;Closas et al. 2005;Cazzulo-Klepzig et al. 2009;Hermann et al. 2012;Wheeler and Götz 2017;Prasad et al. 2013;Aggarwal et al. 2019). ...
An integrated work on palynofloral and palynofacies studies along with megafloral analysis has been carried out with the samples recovered from Balaram Opencast Coal Project (N20°56′58″ latitude and E85°05′31″ longitude), Talcher Basin, Odisha, India. The analyzed samples are characterized by the dominance of degraded organic matter (39–49.5%, avg. 44.2%) and sub-dominance of palynomorphs (13.7–41.2%, avg. 27.45%). Recovered palynoassemblage along with the lithology (carbonaceous shale, dark gray shale, sandstone, silty shale, and coal seams) of the studied area explicitly depicts that the investigated sediments belong to the Barakar Formation of late Early Permian (late Artinskian to Kungurian) age. For the first time, an exclusive record of Vertebraria is made from this location, demonstrating the presence of a deciduous Glossopterids forest during the deposition of Barakar sediments. In addition, the present study also reveals a warm, humid, temperate climate with abundant rainfall during this period. The palynofacies analysis demonstrates a flooded palaeomires/marshy condition in the distal dysoxic-oxic low energy settings during late Artinskian to Kungurian.
... This appears to have been the largest marine transgression to affect this region in the Cenozoic. The Jurassic fossil floras of northeast Sri Lanka (Ratnayake & Sampei, 2015;Weerakoon et al., 2019) and the Neogene lignite floras of Neyveli and Cuddalore in Southeast India (Guleria, 1992), contain no suggestion of a substantial marine inundation until the 24-m transgression ~ 120,000 years ago, in the Pleistocene. We thus consider the topography of the Palk Isthmus to have been stable at least since the late Miocene, with terrestrial connectivity between Sri Lanka and India being mediated by sea level alone. ...
The cyprinid genus Dawkinsia comprises 13 species distributed in lowland streams and rivers in southern peninsular India and Sri Lanka. Eleven species are endemic to India, largely restricted to streams draining the Western Ghats, while one is confined to the Knuckles Hills of Sri Lanka. One species, D. filamentosa, has a wide range, straddling the island and mainland. Here, based on 135 samples representative of all 13 species, collected from 45 locations in India and 17 in Sri Lanka, we present phylogenetic and phylogeographic analyses of Dawkinsia. We use two mitochondrial markers—cytochrome b and cytochrome c oxidase subunit 1. Dawkinsia is recovered as paraphyletic with respect to Sahyadria, with strong node support. The ‘filamentosa group’ which includes both Sri Lankan and Indian taxa (D. filamentosa, D. crassa, D. rohani, D. exclamatio, D. srilankensis, D. tambraparniei, D. arulius, D. rubrotincta and D. uttara) is recovered as the sister group of Sahyadria, a genus confined to the Western Ghats. The ‘assimilis group’, which consists entirely of Indian endemics (D. assimilis, D. austellus, D. apsara and D. lepida), is recovered as the sister group of the ‘filamentosa group’ + Sahyadria. Ancestral-range estimates indicate two colonization events from India to Sri Lanka, across the Palk Isthmus. The first of these, in the Pliocene, involved the common ancestor of D. tambraparniei and D. srilankensis, while the second was of D. filamentosa in the late Pleistocene. Dawkinsia filamentosa shows little phylogeographic structure within or between Sri Lanka and India. Ancestral-range analyses suggest that neither the Palghat nor Shencottah Gaps acted as barriers to the north–south dispersal of Dawkinsia along the Western Ghats. Instead, these valleys appear to have offered lowland passages for west–east colonization by some ancestral species across the Western Ghats ridge. Despite the Palk Isthmus having been subaerial for much of the Plio-Pleistocene and serving as the only terrestrial biotic corridor connecting Sri Lanka to the Asian mainland, it appears to have served also as a climatic filter to dispersal following the aridification of south-eastern India during the Late Miocene/early Pliocene.
... The systematic study of palynomorphs bound with palynofacies studies has become a reliable tool for enhancing the accuracy and consistency (Götz et al. 2003;Cazzulo-Klepzig et al. 2009;Schneebeli-Hermann et al. 2012) in the palaeodepositional researches. Very few palynological investigations have been done in Sri Lankan sediments (Dahanayake et al. 1989;Premathilake 2012;Premathilake et al. 1999;Premathilake and Nilsson 2001;Premathilake and Seneviratne 2015;Weerakoon et al. 2019). Resultantly, detailed palynological studies are required for the understanding of the geological history of this terrain. ...
... Several contributions from Sri Lanka have focused on reconstructing its origin in petrology, sedimentology, and geography (Money and Cooray 1944;Katz 1987;Dahanayake et al. 1989;Kehelpannala 1997;Dissanayake and Chandrajith 1999;Raveendrasinghe et al. 2013;Raveendrasinghe and Dahanayake 2014). However, the research contribution in palynostratigraphy and palynofacies are very few due to lack of the upper Gondwana deposits (Dahanayake et al. 1989;Premathilake et al. 1999;Premathilake and Nilsson 2001;Premaratne and Rowson 2003;Premathilake 2006;2012;Premathilake and Seneviratne 2015;Weerakoon et al. 2019). Geologically, around ten percent of sedimentary rocks (Cooray 1984) are present within the island. ...
... The study involves biostratigraphy and palaeoclimatic reconstruction with the recovered palynomorphs, other constituents of the palynofacies, and sedimentological studies. Significant palynomorphs and organic matter (OM) in palynofacies analysis along with sedimentological characters Weerakoon et al. 2019) are used to deduce stratigraphy and age, depositional history, and palaeoenvironments of the different sediments. ...
Sri Lanka consists of only ten percent of sedimentary rocks, and high-grade metamorphic rocks underlie the rest. Most of these sedimentary terrains are post-Gondwanic and such formations help to understand the geological history of the island. We report the first record of an age diagnostic (Late Jurassic-Early Cretaceous) palynological assemblage of the sedimentary rocks in the Andigama basin (borehole AND BH01) Sri Lanka. The study was undertaken to assess the palaeoenvironmental settings in this basin based on palynological and palynofacies investigations. A palynofloral study suggests luxuriant gymnospermous forests proliferation in the Andigama Basin during this time. The palynological assemblage is characterized by the predominance of coniferous pollen grains of Araucariacites spp., Callialasporites spp. Along with some stratigraphically significant taxa viz., Cicatricosisporites spp., Aequitriradites verrucosus, Triporoletes sp., Impardecispora indica, Concavissimisporites verrucatus, Distaltriangulisporites perplexus, Verrucosisporites verrucosus, and Contignisporites fornicates of Tithonian-Berriasian time. Palynofacies records suggest three distinct Palynofacies Assemblages (PF 1-3). PF 1 indicates the forest swamp; PF 2 represents the mixed assemblage of forest swamp and reed marshes, while PF 3 suggests reed marshes/lakeshore deposits under oxic-anoxic environments. These palynofacies assemblage along with variable lithological counterparts varying from carbonaceous shale laminae interlayered with calcareous sandstone to brown shale and carbonaceous shale strata reflects diverse hydrodynamic conditions. Palynofloral and palynofacies records of the present study denote the warm and humid climatic conditions, which directly corroborates with global oxygen isotopic studies of the Late Jurassic-Early Cretaceous sediments.
... Palynomorphs studies, along with palynofacies, are one of the reliable proxies in palaeoclimatic reconstruction to enhance our understanding of processdriven changes in depositional setting. Previous studies have also bound the application of palynology and palynofacies to reconstruct depositional conditions concerning the Gondwana sedimentation Götz et al., 2017Götz et al., , 2018Mishra et al., 2017;Weerakoon et al., 2019). The base of the Gondwana deposits was glacial, which have been overlained by the fluvial system with broad floodplains and well-defined channels due to which signals of climatic manifestations are observed in Indian Gondwana basins (Dutta, 2002). ...
Despite advances in biodiversity exploration, the origins of Sri Lanka's fauna and flora have never yet been treated in a synthetic work. This book draws together the threads that make up that fascinating 100-million year story. Encompassing the island's entire biota while emphasising the ecology, biogeography and phylogeography of freshwater fishes, it provides a comprehensive context for understanding how the island's plants and animals came to be as they are. The 258-page text contains more than 200 figures, photographs and maps. It provides a clear account of how, when and from where the ancestors of the plants and animals that now inhabit Sri Lanka came. For the first time, the island's unique biodiversity can be understood and appreciated in its historical and evolutionary context in this invaluable sourcebook, designed for scientists, students and biodiversity enthusiasts alike.
Palynofacies is based on the different types of the dispersed/sedimentary organic matter (DOM/SOM) and has been used as a proficient proxy for the palaeoclimatic reconstructions in sedimentary deposits of various time spans. It has also been acknowledged as an effective tool in the different domains like sequence biostratigraphy, palyno-biostratigraphy, palaeodepositional history, identification for depositional processes, oxic–anoxic environment, and variations in the water depth. It has been emerged as an analytical tool in palaeoclimatic reconstruction, which could complement geophysical and geochemical datasets. Since long palynofacies analysis has been exclusively applied in the marine sediments, it has recently dragged the attention of many researchers as a significant parameter for palaeoclimatic interpretation in continental deposits. In the last few decades, more consideration was focused on palynofacies that have become an essential proxy in the biostratigraphic and other non-biostratigraphic fields due to its requirement in the petroleum industries. The present study provides a basic idea of dispersed organic matter characterization, methodology, interpretations, and its application with special emphasis on the Gondwana deposits. The study also includes the summary of the worldwide distribution of the Gondwana sediments, especially for palaeodepositional settings through palynofacies along with other parameters.
