148-16 Granulometric Analysis of Coastal Sediments: Link to Sedimentary Processes and Foraminiferal Biofacies across Coastal Regions of Bangladesh

Session: Insights from Microfossils and Their Modern Analogs: From Traditional to Emerging Approaches (Posters)

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Abiotic factors such as sediment texture and sedimentary processes are significant determinants of foraminiferal assemblage composition and distribution. This study presents a comprehensive quantitative analysis to elucidate the abundance and distribution of foraminiferal assemblages and the granulometric characteristics of sediments across various coastal regions of Bangladesh, centered on three ecologically important areas: Sundarbans, Kuakata, and Cox’s Bazar.  On this rationale, 50 sediment samples (top 0-50 cm) were obtained along the land-sea transect.Sediment samples were systematically obtained from various coastal settings, including tidal mudflats, estuarine areas, and sandy beaches.  Detailed grain size analyseswere performed utilizing established graphical method.  The integration of bivariate plots, linear, and multigroup discriminant functions further differentiated the predominant depositional environments, highlighting the dynamic impact of aeolian, beach, shallow marine, fluvial, and marine turbidity processes throughout the regions.  Foraminiferal specimens were carefully extracted, identified using high-resolution microscopy and recognized taxonomic keys. Statistical methods, including Pearson Correlation and Principal Component Analysis, were employed to illustrate the links between sediment texture and foraminiferal distribution.  The findings indicate that variations in grain size and depositional energy substantially influence the composition and distribution of foraminiferal communities. Key findings reveal that Sundarban sediments linked to low-energy depositional environments sustain unique and less diverse foraminiferal populations.   Conversely, areas with mixed or coarser sediments, typically influenced by higher energy and fluctuating depositional conditions, foster greater foraminiferal diversity.  The sediments of Cox's Bazar exhibited the highest diversity of foraminiferal species in comparison to the other two locations.  The genera Ammonia and Elphidium predominated in all foraminiferal assemblages.This study enhances comprehension of sedimentary influences on foraminiferal ecology in the coastal regions of Bangladesh and establishes a methodological and analytical framework that can guide future paleoenvironmental reconstructions and ecological evaluations in analogous coastal settings.

Key Words: Granulometric, Sedimentary Processes, Foraminifera, Biofacies, Coastal Regions, Bangladesh

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9658

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