66 Environmental Instability During Greenhouse Periods: Impact on Terrestrial and Marine Ecosystems (Posters)

Greenhouse conditions and transitions to and from such climate states put environmental stress on terrestrial and marine ecosystems. We invite contributions that leverage multidisciplinary/proxy approaches to constrain the impact of environmental changes on paleobiodiversity.

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Lower Cretaceous Paleoecological change at Wadi Muaydin, Oman: a multidisciplinary approach

Paper number: 66-1
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

During the Early Cretaceous, major paleoenvironmental perturbations included intensified nutrient cycling and global warming. This culminated in events such as the early Aptian Oceanic Anoxic Event 1a. These episodes affected marine carbonate ecosystems as observed by faunal assemblages and facies architecture changes in platform carbonates such as in Oman. This research aims at illustrating how shifts in the shallow water carbonate facies and benthic faunal assemblages in the Barremian-Aptian of northern Oman reflect paleoenvironmental changes, such as sea-level fluctuations, nutrient influx, and detrital input. We hypothesize that the succession from orbitolinid-rich facies to microbialite and rudist-dominated beds reflects a paleoecological response to changing nutrient input and sea level, with microbialites reflecting periods of elevated productivity and platform stress. To test this hypothesis, we consider the Wadi Muaydin section that captures the evolution of a carbonate platform system. A total of 47 thin sections were analyzed to interpret ecology of the ecosystem. Concentration of titanium and phosphorus (determined by XRF analysis) informed on the level of detrital and nutrient input. Lastly, slabbed samples were micro sampled for carbon and oxygen stable isotope analysis), to help identify perturbations in the carbon cycle and assess the impact of diagenesis. Preliminary observations indicate a fossil content increase from the base of the studied interval in the Wadi Muaydin section, with a dominance of rudists that could reflect optimal salinity and nutrient levels in shallow marine environments along the Neo-Tethyan margin during a time of major global environmental change.

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

doi: 10.1130/abs/2025AM-413483

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