Upper Carboniferous-Lower Permian Buildups of The Carnic Alps, Austria-Italy

Abstract

A variety of buildup types occur in the upper Paleozoic Auernig and Rattendorf Groups, Carnic Alps, at the present-day Austrian-Italian border, including coral, diverse algal (Anthracoporella, Archaeolithophyllum, Rectangulina, and phylloid green), bryozoan, brachiopod, and sponge buildups. Thin mounds and banks have a diverse fossil association (e.g., Archaeolithophyllum-bryozoanbrachiopod mounds) and occur in siliciclastic-dominated intervals, as do coral buildups. Some of the biodiverse thin mounds occur in strata that were deposited in cooler water. However, the thickest mounds are nearly monospecific (e.g., Anthracoporella mounds) and grew in carbonate-dominated, warm-water environments.Most of the mounds considered in this paper, particularly algal mounds, grew in quiet-water environments below wave base but within the photic zone. Mound growth was variously stopped by siliciclastic input, e.g., auloporid coral mounds, sea-level rise, e.g., the drowning of Anthracoporella mounds of the Rattendorf Group, influence of cool water, e.g., algal mounds of the Auernig Group overlain by limestone of cool-water biotic association, or sea-level fall, e.g., phylloid algal mounds that were subsequently exposed subaerially. There is no indication of ecological succession during mound growth. Growth, dimensions, biotic association, and termination of mounds seem to have been controlled by extrinsic factors, mainly sea level and water temperature.Phylloid algal mounds are similar to those described from other late Paleozoic settings. Auloporid coral buildups, and Rectangulina and Anthracoporella algal buildups, however, have not previously been reported from other regions, although these fossils are described from several localities outside the Carnic Alps.Permo-Carboniferous Carbonate Platforms and Reefs SEPM Special Publication No. 78 and AAPG Memoir 83,

The influence of terrestrial run off on marine biotic communities: An example from a thrust-top carbonate ramp (Upper Pennsylvanian foreland basin, Picos de Europa, NW Spain)

“…The widespread Anthracoporella and phylloid algal mounds (facies Md3 and Md4), commonly assigned to shallow, low-energy settings (Krainer, 1995;Samankassou, 1997Samankassou, , 1998Samankassou, , 1999Soreghan and Giles, 1999;Samankassou, 2003), the abundance of chaetetid sponges, calcareous green algae and large benthic foraminifers (fusulinoideans, palaeotextulariids, bradyinids and Staffella) along with levels rich in Osagia-type oncoids agree with this interpretation. The various types of buildups in the study area are comparable to those reported throughout Late Palaeozoic deposits by previous authors.…”

“…Anthracoporella-dominated algal mounds, first described in the Carnic Alps by Krainer (1995) and Samankassou (1997Samankassou ( , 1998Samankassou ( , 1999Samankassou ( , 2003, were rarely reported in coeval successions elsewhere. Overall, the studied Anthracoporella mounds show striking similarities to those described in the Carnic Alps.…”

Paleoecology of Pennsylvanian phylloid algal buildups in south Guizhou, China

“…Low-diversity algal mounds occurring throughout Pennsylvanian and Permian deposits strongly support this assumption (Flügel 1979;Toomey 1991;Forsythe et al 2002;Samankassou 2003;Samankassou and West 2003). Indeed, chemical defense used by algae is documented from studies of recent reefs (Hay 1997;Paul 1997) and other environments (G. Gerdes, personal communication, 1998).…”

“…Scale bar is 0.5 mm for all Wgures ᭣ Temperature and water depth Phylloid algae in south China, assumedly photosynthetic green algae, are associated with colonial corals and fusulinids: this may point to a shallow-water depositional environment within the photic zone. The growth of phylloid algal reefs is interpreted to have taken place between the lower limit of the photic zone (the deepest) and the zone close to the lower limit of the wave activity (the shallowest) (see Doherty et al 2002;Samankassou 2003). Considering the wide depth ranges of modern green algae and algal mounds (e.g., 20-100 m for Halimeda mounds in the eastern Java Sea; ), a precise water depth cannot realistically be deduced.…”

“…Although numerous studies dealt with Pennsylvanian and Permian sequences in southern China (GGMRB 1987), Pennsylvanian algal buildups so widespread elsewhere-e.g., in Northern America (Pray and Wray 1963;Heckel and Cocke 1969;Toomey 1976Toomey , 1983; among others), the Arctic Canadian Archipelago Davies et al 1989), the Carnic Alps in Austria and Italy (Flügel 1979;Samankassou 2003), and North Africa (Toomey 1991)-were surprisingly rarely reported from China, which is among the largest province for Late Paleozoic carbonate rocks (see Wahlman 2002). The short report of phylloid algal reefs by Fan and Rigby (1994) is the unique description to date.…”