bibliography - various topics

Reefs / 12th March 2017

BERESI M. S., CABALERI N. G., LOESER H., ARMELLA C. 2017. Coral patch reef system and associated facies from southwestern Gondwana: paleoenvironmental evolution of the Oxfordian shallow-marine carbonate platform at Portada Covunco, Neuquen Basin, Argentina. Facies 63, 4: 1-22. doi:10.1007/s10347-016-0486-4
[keywords: Middle Oxfordian; La Manga Formation; Coral reefs; Facies/microfacies; Paleoenvironments; Argentina; Neuquen Basin]
[pagination supplemented; for abstract see FC&P40: 85]

El-SOROGY A. S., ISMAIL A., YOUSSEF M., NOUR H. 2016. Facies development and paleoenvironment of the Hajajah Limestone Member, Aruma Formation, central Saudi Arabia. Journal of African Earth Sciences 124: 355-364.
The Campanian Hajajah Limestone Member of the Aruma Formation was formed during two regressive episodes. Each of them formed of three depositional facies, from base to top: 1) intra-shelf basin facies, made up of fossiliferous green shale and mudstone with ostracods and badly preserved foraminifers. 2) fore-reef facies, consists of hard, massive, marly coralline limestone. The upper part is rich with low diversity, badly to moderate preserved, solitary and colonial corals, and, 3) back reef and near-shore facies, consists of fossiliferous sandy dolomitized, bioturbated limestone with abundant reworked corals, bivalves, gastropods, and aggregate grains. On the basis of field observations, micro- and macrofossils and microfacies analysis, the Hajajah Limestone Member was deposited in distal marine settings below storm wave base in a low-energy environment changed upward to fore-reef framework in an open marine environment with moderate to high energy conditions and terminated with shallow marine facies with accumulation of skeletal grains by storms during regression. [original abstract; Löser]

VESCOGNI A., BOSELLINI F. R., PAPAZZONI C. A., GIUSBERTI L., ROGHI G., FORNACIARI E., DOMINICI S., ZORZIN R. 2016. Coralgal buildups associated with the Bolca Fossil-Lagerstätten: new evidence from the Ypresian of Monte Postale (NE Italy). Facies 62, 21: 1-20.
The Monte Postale and Pesciara di Bolca sites are well-known Eocene Fossil-Lagerstätten. The origin of these deposits has been previously related to a lagoon environment, protected from the open sea by a barrier formed by some kind of reef. However, no detailed description of a bioconstructed system has ever been reported in the area. This study provides the first detailed characterization of the upper Ypresian Monte Postale reef, made of in situ corals, calcareous algae, and encrusting foraminifera. Three main facies associations have been recognized: (1) a coralgal rim, roughly E/W oriented, (2) lagoon deposits in the south and (3) fore-reef sediments towards the north. The coralgal rim is represented by a wave-resistant framework made of heavily calciied organisms associated to Alveolina accumulations; the adaptation of most of these organisms to the euphotic zone promoted their growth in proximity to the sea level, allowing this structure to act as an effective barrier. In particular, during relative sea-level lowstands or highstands, the coralgal rim could have limited the water exchange between the lagoon and the open sea, reducing the oxygenation in the lagoon and allowing the formation of the Fossil-Lagerstätten. During relative sea-level transgressions, the water could have risen well above the margin, establishing normal oxygenation and hampering the fossils' preservation. The Monte Postale succession represents one of the few examples of lower Eocene bioconstructions. The description of this biotic assemblage provides new data for the characterization of reef communities during a crucial climatic phase, near the end of the early Eocene climatic optimum global warming. [original abstract; Löser]