Depositional environment is an important aspect of sedimentary geology because it records paleoenvironmental conditions and sedimentation processes during rock formation. However, integrated paleontological and petrographic studies on the Sukaraja Member of the Bentang Formation remain limited. This study aims to interpret the depositional environment of the Sukaraja Member based on paleontological and petrographic analyses. The research was conducted through field observations, rock sampling, micropaleontological analysis, and petrographic examination using thin sections under a polarizing microscope. The results indicate that the Sukaraja Member is composed of sandy limestone characterized by packstone texture, micrite matrix, and parallel bedding structures, reflecting low to moderate depositional energy. Micropaleontological analysis indicates a Late Miocene age (N16 zone), while benthic foraminiferal assemblages suggest a marginal to middle neritic environment with estimated depths ranging from 118 to 182 m. The integration of petrographic characteristics, sedimentary structures, and fossil assemblages indicates that the Sukaraja Member of the Bentang Formation was deposited in a back reef carbonate environment characterized by relatively calm water conditions and limited clastic sediment supply.
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