Near Watson (Miocene of Australia)

Where: South Australia, Australia (30.5° S, 131.5° E: paleocoordinates 39.9° S, 127.9° E)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Nullarbor Formation, Langhian (16.0 - 13.8 Ma)

• Presence of Austrotrillina howchini and Flosculinella bontangensis in the Nullarbor Limestone suggest Middle Miocene age. "Late early Miocene to early middle Miocene" according to O'Connell et al. (2012). Watson Quarry section exposes the upper part of the Nullarbor (O'Connell et al., 2012), so an early middle Miocene age assigned here.

• group of beds-level stratigraphic resolution

Environment/lithology: open shallow subtidal; lithified limestone

• Facies are dominated byskeletal grainstones andfloatstones that accumulated in three interpreted paleoenvironments: (1) seagrass banks (upper photic zone), (2) rhodolith pavements (lower photic zone), and (3) open seafloors (lower photicto subphotic zone). The Southern Ocean extended inboard ~450 km from the shelf edge during Nullarbor Limestone deposition, but interpreted paleodepths did not extend much below the base of the photic zone. A small slope angle (~0.02°) over a wide shelf (~300,000 km2) implies deposition on an epeiric platform or epeiric ramp. A Miocene barrier reef was likely coeval with Nullarbor Limestone deposition. Therefore, the inboard portion of the Nullarbor Limestone can be considered part of an extensive back-reef lagoon system on a rimmed epeiric platform, perhaps attaining asize similar to the modern Great Barrier Reef system.

Size class: macrofossils

Collection methods: Repository: South Australian Museum

Primary reference: B. McGowran. 1959. Tertiary nautiloids (Eutrephoceras and Cimomia) from South Australia. Journal of Paleontology 33:435-448 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 171279: authorized by Matthew Clapham, entered by Matthew Clapham on 05.07.2015

Creative Commons license: CC BY (attribution)

Taxonomic list

Cephalopoda
 Nautilida - Nautilidae
"Eutrephoceras geelongensis" = Nautilus geelongensis
"Eutrephoceras geelongensis" = Nautilus geelongensis Foord 1891 nautiloid