Foraminifera and Their Habitats Within a Cool-Water Carbonate Succession Following Glaciation, Early Permian (Sakmarian), Western Australia

Abstract

One of the best-developed carbonate successions of the Lower Permian in eastern Gondwana is the Callytharra Formation, deposited above glacially influenced sediments in a narrow elongate rift basin far from the open ocean. This formation and the underlying Carrandibby Formation provide evidence for faunal changes that accompanied the melting of the Sakmarian Gondwanan ice sheets. Diverse smaller benthic foraminifera including organic-cemented agglutinated, hyaline, and porcelaneous calcitic forms, accompany a heterozoan macrofauna (mainly bryozoans, crinoids and brachiopods). Fusulinid foraminifera and calcareous algae are absent. Seven foraminiferal assemblage zones subdivide the succession and parallel changes in associated macrofauna and lithofacies. Environmental changes determined from the succession include (1) a transition from nearshore, lowenergy, low-salinity, cool waters to higher-energy, normal-marine waters supporting bryozoan, crinoidal and non-skeletal-macroalgal meadows; and (2) a transition from well-oxygenated, shallow-water, sandy substrates to deeper-water, less-oxygenated, muddy substrates. Faunal comparisons suggest that at paleolatitudes higher than 45؇S, in widely separated interior basins in eastern Gondwana, a change from low-diversity, siliceous-agglutinated to high-diversity, Calcitornella-rich, foraminiferal assemblages took place during the Sakmarian. This change may have been associated with a reduction in melt-water influx into the interior basins from retreating Gondwanan ice sheets. The warming was insufficient to allow colonization of the shallow seas by fusulinids and calcareous algae, which only ranged as far south as 45؇S paleolatitude.

Faunal similarity in Madagascan and South Indian Late Cretaceous vertebrate faunas

“…Protonodosaria is not recorded higher in the succession here or in BHP PND-1 but dominates assemblages in older Permian units in the Southern Carnarvon and Perth basins (Crespin, 1958;Foster et al, 1985;Palmieri, 1993;Dixon and Haig, 2004). Nodosaria with radiate rather than Protonodosaria proceraformis (Gerke), which is very similar to P. tereta (Crespin) of the fossil groups in sections elsewhere in East Gondwana particularly those more proximal to the Mesotethyan Ocean.…”

“…A C C E P T E D M A N U S C R I P T (Dixon and Haig, 2004) and morphologically close to, although slightly larger than, S. pulchra Kireyeva…”

“…6C) that contain shallow-water foraminifera (e.g. Calcitornella sp., Hedraites plummerae, Trepeilopsis australiensis) which probably lived attached to non-skeletal algae in the upper photic zone (see discussion in Dixon and Haig, 2004). These and some of the echinodermal, bryozoan and brachiopod debris probably have been transported from their life environments, perhaps downslope into deeper water.…”

A latest Carboniferous warming spike recorded by a fusulinid-rich bioherm in Timor Leste: Implications for East Gondwana deglaciation

“…Conditions within the very shallow intracratonic sea to the south of Timor fluctuated in terms of nutrition, salinity, water depths, and temperature (Haig, 2003(Haig, , 2004Dixon and Haig, 2004). The marine stratigraphic record in the more southern basins consists mainly of sandstone/mudstone cycles with isolated beds in the succession containing shelly macrofauna that usually differs in composition from fossiliferous beds above and below.…”

“…The marine stratigraphic record in the more southern basins consists mainly of sandstone/mudstone cycles with isolated beds in the succession containing shelly macrofauna that usually differs in composition from fossiliferous beds above and below. The exception, deposited at the end of the Early Permian deglaciation interval, is the Upper Sakmarian Callytharra Formation and its correlatives where fossiliferous limestone is present at the top of frequent sedimentary cycles (Dixon and Haig, 2004).…”