Facies analysis and depositional sequences of a siliciclastic–carbonate deposit: the Late Paleocene–Early Eocene succession, Fariman, Central Iran

Abstract

A mixed carbonate–siliciclastic succession in Central Iran was investigated using detailed field and laboratory studies. The succession represents a shallow marine to coastal plain setting and a fluvial depositional system. Based on sedimentological analysis, six facies are identified: (1) pelagic and shelf-to-lagoon sediments (lime/silt/clay mudstone), (2) shoal sediments (thin-bedded limestone), (3) shelf-to-lagoon sediments (limestone), (4) tidal flat sediments (lime mudstone/dolomite/evaporites), and (5/6) fluvial deposits (sandstone and conglomerate). The Kariz-Bolagh strata contain parasequences as part of fourth-order depositional sequences. Uplift, compaction, and rate of deposition were the main factors that controlled the vertical facies transitions in these parasequences. This succession provides an excellent opportunity to study the interplay between shallow-water sedimentation and syndepositional subsidence. The effects of these processes caused relative sea level changes, variation in depositional parasequences, and formation of sequence boundaries. The Kariz-Bolagh strata contain type 1 sequence boundaries. Due to local structural events in the basin, the interpreted sea level curve during deposition of the Late Paleocene–Early Eocene strata cannot be correlated with the world sea level curve.