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Denmark Hill Insect Bed (Dunstan 1915-1916 collection) (Triassic of Australia)

Where: Queensland, Australia (27.6° S, 152.8° E: paleocoordinates 58.6° S, 101.0° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Blackstone Formation (Ipswich Coal Measures Group), Norian (221.5 - 205.6 Ma)

• Insect bed is about 50 feet above the Bluff coal seam and 50 feet below the Aberdare coal seam. Fossil bed is 15 cm thick. Purdy & Cranfield (2013) reported an unpublished SHRIMP date of 2262 Ma for the Brisbane Tuff. Therefore, the Blackstone Formation may be considered younger than 226 Ma in absolute age. Thus, the Ipswich Coal Measures above the Brisbane Tuff, which is to say, the succession from the Mount Crosby Formation to the top of the Blackstone Formation must now be considered Norian.

• bed-level stratigraphic resolution

Environment/lithology: pond; lithified, sandy siltstone

• Interbedded sandstones and mudstones accumulated on levees bordering channels and graded laterally into floodplains where carbonaceous mudstones accumulated with thin crevasse splay sandstone beds.

•Ipswich basin; transtensional rift in intermontane setting. Basin geometry affected by strike-slip movement along West Ipswich fault. Ipswich coal measures deposited near end of rifting phase.

• "The fossil insect bed of finely arenaceous shale. Near the outcrop the bed is of a brownish grey colour with iron-stained joints and planes." Dunstan, 1916 Fresher rock is a greenish grey colour.

Size classes: macrofossils, mesofossils

Preservation: mold/impression, adpression

Collected by Dunstan & Wilcox in 1915-1916

Primary reference: R. J. Tillyard. 1917. Mesozoic Insects of Queensland No. 1 Planipennia, Trichoptera, and the new order Protomecoptera. The Proceedings of the Linnean Society of New South Wales 42(165):175-200 [M. Clapham/J. Karr] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 111558: authorized by Matthew Clapham, entered by Jered Karr on 25.06.2011, edited by Matthew Clapham

Creative Commons license: CC BY (attribution)