W-Fold deposit, borehole WF 13, 253.5 m depth (Statherian of Australia)

Where: Northern Territory, Australia (16.4° S, 136.0° E: paleocoordinates 0.0° N, 0.0° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: H.Y.C. Pyritic Shale Member (Barney Creek Formation), Statherian (1800.0 - 1600.0 Ma)

• Ash beds within the Barney Creek Formation yielded U-Pb SHRIMP ages of 1638 +/- 7 Ma, 1639 +/- 3 Ma, and 1640 +/- 3 Ma, with the underlying Teena Dolomite yielding an indistinguishable age of 1639 +/- 6 Ma (Page et al., 2000). The overlying Lynott Formation was dated at 1636 +/- 4 Ma (Page et al., 2000).

• bed-level stratigraphic resolution

Environment/lithology: basinal (); lithified, pyritic, cherty/siliceous shale

• The preferential pyritization of the bacterial fossils (as compared with the algal fossils) suggests that the bacteria inhabited anoxic, iron sulfide-rich muds at the bottom of the basin. If the basin floor could support a bacterial population (which presumably was heterotrophic) but not an algal population (which almost certainly was photoautotrophic), then it is reasonable to infer that the depth of the basin exceeded that of the photic zone. This inference drawn from

•paleontological data is consistent with earlier depth estimates of 300 to 800 m (Brown & Plumb in Plumb & Derrick, 1975) drawn from geological data.

Size class: microfossils

Preservation: permineralized, replaced with silica, replaced with pyrite

Collection methods: core, peel or thin section

• Repository: Commonwealth Palaeontology Collection, Canberra

Primary reference: J. H. Oehler. 1977. Microflora of the H.Y.C. Pyritic Shale Member of the Barney Creek Formation (McArthur Group), middle Proterozoic of northern Australia. Alcheringa 1:315-349 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 227582: authorized by Matthew Clapham, entered by Matthew Clapham on 16.10.2022

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Coccogoneae
 Chroococcales - Chroococcaceae
Bisacculoides tabeoviscus
Hormogoneae
 Oscillatoriales - Oscillatoriaceae
Cyanonema inflatum n. sp.
Cyanonema inflatum n. sp. Oehler 1977
 Life -
Clonophycus elegans n. sp.
Clonophycus elegans n. sp. Oehler 1977