Calcareous nannofloras in Western Lobe Offshore, Niger Delta: Eutrophication and climate change implications

نویسندگان

چکیده

In support of the on-going temporal palaeoenvironmental and palaeoclimatic reconstructions Neogene sediments, this study attempts describing palaeo-proxies recovered from DEL-1 Well, western offshore Niger Delta. The use standard smear slide method enabled recovery well-preserved calcareous nannofossils that depicts early to mid – Miocene (NN4 NN5) sediments. up-hole relationships between relative abundance Discoaster spp. coccolith size Reticulofenestra show step by collapse sea surface stability middle Miocene. lower horizons (8000-9460 ft.) exhibit relatively high large suggest a deep thermocline nutricline characterize oligotrophic conditions in less warm-water induced climate. Conversely, upper (5225-6550 significant changes with low small shallow eutrophic Helicosphaera coccoliths ( carteri ) within - NN5, suggests mesotrophic stressed environment (fluctuating salinity terrigenous influx) occurrence carbonate fluctuating event. combined parameters indicate gradual eutrophication favour nutrients influx fluvial mechanism (terrestrial input) ocean water as it progressed assemblages depict hyposaline waters neritic environment, characterized warm climatic conditions. Keywords : Calcareous nannofossils, Delta, palaeoecology, thermocline, sea-surface stability.

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ژورنال

عنوان ژورنال: Geografia

سال: 2021

ISSN: ['0102-3888', '2447-1747']

DOI: https://doi.org/10.17576/geo-2021-1704-19