Facies architecture and geometry of a prograding carbonate ramp during the early stages of foreland basin evolution: Lower Eocene sequences, Sierra del Cadí, SE Pyrenees, Spain

Abstract

This paper describes the Early Eocene sedimentological evolution of the Sierra del Cad/carbonate platform during the early development of the southeastern Pyrenean foreland basin, Spain. The platform developed as a south-facing ramp system located either across the southern margin of a growth anticline within the newly formed basin or along the axial margin of the basin. Sequences I and II both comprise basal transgressive systems tracts (TSTs) dominated by a thick succession of outer ramp lime mudstones, shallowing upwards into a highstand systems tract (HST) of mid-and inner ramp bioclastic shoals, sand banks and lagoonal deposits. In Sequence III the TST comprises a thick,

Evolution of shallow benthic communities during the Late Paleocene–earliest Eocene transition in the Northern Tethys (SW Slovenia)

“…Fossil, the large, Xat form of Assilina, were interpreted as living in the deeper parts of the photic zone (e.g., Oman; Racey 1994) but also as shallow-water dwellers in turbid fore-and back-reef environments (e.g., Early Eocene forms from the South Pyrenean foreland; Gilham and Bristow 1998;Ghose 1977). The paleoecology of the other larger foraminifera found in the assemblage is here only tentatively inferred because extant counterparts do not exist.…”

“…Fossil orthophragminids have been described from a diverse array of environments within the photic zone including shallow back-and fore-reef/shoal environments (e.g., Anketell and Mriheel 2000;Ghose 1977) to deeper, outer ramp environments (e.g. Gilham and Bristow 1998). Their test morphologies were proposed as a feature to diVerentiate inner-ramp environments above the FWWB (ovate form) from mid-to outer-ramp areas (Xattened forms; e.g., Eocene from Tunisia; Loucks et al 1998).…”

Applications of nummulitids and other larger benthic foraminifera in depositional environment and sequence stratigraphy: an example from the Eocene deposits in Zagros Basin, SW Iran

“…6a). Large, Xat Assilina have been interpreted as forms that lived in deep, oligophotic water (Racey 1994;Luterbacher 1998;Geel 2000), and also in much shallower, open marine, high-energy settings (Ghose 1977;Gilham and Bristow 1998). Although the genus Assilina is now extinct, living nummulitids with similar large, Xat tests (e.g.…”

The Middle Eocene Seeb Formation of Oman: An Investigation of Acyclicity, Stratigraphic Completeness, and Accumulation Rates in Shallow Marine Carbonate Settings

“…Large, flat Assilina have previously been interpreted as forms that lived in deep, oligophotic water (e.g., Racey 1994;Luterbacher 1998;Geel 2000), and also in much shallower, open marine, high-energy settings (e.g., Ghose 1977;Gilham and Bristow 1998). Although the genus Assilina is now extinct, living nummulitids with similar large, flat tests (e.g., Cycloclypeus carpenteri and Heterocyclina tuberculata) have been collected from water depths up to 150 m (e.g., Reiss and Hottinger 1984;Hohenegger 2000), although Assilina examined during this study generally exhibit far thicker test walls than those of their more fragile, extant relatives.…”

“…Previous studies have interpreted Discocyclina as having lived in a broad spectrum of environments in the photic zone, including shallow fore-reef and backreef environments (e.g., Henson 1950;Racz 1979;Anketell and Mriheel 2000) and deeper, outer-ramp environments (e.g., Racey 1994;Gilham and Bristow 1998). Other authors have noted an environmental control on test morphology, with Discocyclina in very shallow photic-zone settings having small, robust tests, whilst those living in lower-light, deeper settings have large flattened tests (e.g., Ghose 1977;Loucks et al 1998;Sinclair et al 1998;Geel 2000).…”