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    Crustose red algae in deep time environments: Palaeoecological insights from northeastern India and Türkiye (Turkey)
    (Elsevier B.V., 2024) Sarkar, Suman; Sinanoglu, Derya; Özgen-Erdem, Nazire
    Crustose red calcareous algae are key organisms in benthic ecosystems worldwide with critical functions like reef-building and substrate stabilization. Coralline algae thrived as major carbonate producers, with corals and/or larger benthic foraminifera (LBF) in numerous shallow-marine Tethyan carbonate platforms from the early Palaeogene to the Neogene. The Palaeocene–Eocene limestone successions in the Jaintia and Khasi Hills, Meghalaya, northeastern India, encompass two principal community types — algal-foraminiferal and coralline algal, with no associated colonial corals, while the Oligocene–Miocene carbonates from the Sivas basin and Siirt province in Türkiye are characterized by an algal-foraminifera assemblage with bryozoans, corals, and molluscs as other noteworthy components pertinent to the carbonate platform environment. We found that the diversity and ecology of these algal communities were influenced by systematic structure of the algal assemblage, sediment input, substrate stability, water depth, and hydrodynamic energy. The algal assemblages from different epochs and varying localities diverge based on the sedimentary regime, environmental settings, and the predominant taxa. The climatic transition from the Palaeocene–Eocene greenhouse to the Oligocene–Miocene icehouse corresponded to a shift from crustose algal assemblages dominated by Sporolithales to assemblages dominated by Hapalidiales. © 2024 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS
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    Distribution of Alveolina assemblages in the Ypresian (Herdian-Cuisian) successions from Iran and Turkey central and western Tethys): biostratigraphic implications for regional correlation
    (Micro Press, 2020) Hadi, Mehdi; Ozgen-Erdem, Nazire; Sinanoglu, Derya; Sarkar, Suman; Zareh, Azam
    Benthic foraminiferal assemblages dominated by Alveolina species from the Ypresian (Herdian-Cuisian) are studied herein from numerous localities of Iran and Turkey. From these successions, highly diversified assemblage of 58 alveolinid species are identified along with their detailed biostratigraphical application, which resulted in the recognition of eight shallow benthic zones (SBZ5-SBZ 12). Our findings are based upon the distribution ranges ofAlveolina from the Ilerdian-Cuisian sediments in Iran (Central Tethys) that are considered to have a strong affinity with their coeval fauna in Turkey (Western Tethys). In this study, the wide expansion ranges of Alveolina permit us to achieve a high-resolution biostratigraphy and apply the shallow benthic zones of the peri-Mediterranean region (Western Tethys) to the Ilerdian-Cuisian successions in Iran (Central Tethys). Nevertheless, the distribution of some Alveolina species, even the zonal markers consisting of Glomalveolina lepidula, Alveolina ellipsoidalis, A. pisifonnis, A. laxa, A. subpyrenaica, A. varians, A. fornasinii and A . canavarii are found occurring at younger stratigraphic levels in Iran and/or Turkey than in the western European shallow marine deposits.
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    Distribution of Alveolina assemblages in the Ypresian (Ilerdian-Cuisian) successions from Iran and Turkey (central and western Tethys): Biostratigraphic implications for regional correlation
    (Micropaleontology Press, 2020) Hadi, Mehdi; Özgen-Erdem, Nazire; Sinanoğlu, Derya; Sarkar, Suman; Zareh, Azam
    Benthic foraminiferal assemblages dominated by Alveolina species from the Ypresian (Ilerdian-Cuisian) are studied herein from numerous localities of Iran and Turkey. From these successions, highly diversified assemblage of 58 alveolinid species are identified along with their detailed biostratigraphical application, which resulted in the recognition of eight shallow benthic zones (SBZ5-SBZ12). Our findings are based upon the distribution ranges of Alveolina from the Ilerdian-Cuisian sediments in Iran (Central Tethys) that are considered to have a strong affinity with their coeval fauna in Turkey (Western Tethys). In this study, the wide expansion ranges of Alveolina permit us to achieve a high-resolution biostratigraphy and apply the shallow benthic zones of the peri-Mediterranean region (Western Tethys) to the Ilerdian-Cuisian successions in Iran (Central Tethys). Nevertheless, the distribution of some Alveolina species, even the zonal markers consisting of Glomalveolina lepidula, Alveolina ellipsoidalis, A. pisiformis, A. laxa, A. subpyrenaica, A. varians, A. fornasinii and A. canavarii are found occurring at younger stratigraphic levels in Iran and/or Turkey than in the western European shallow marine deposits. © 2020 Micropaleontology Press. All rights reserved.