Mintaja 2 outcrop, Hill River region (Jurassic of Australia)

Where: Western Australia, Australia (30.3° S, 115.2° E: paleocoordinates 39.3° S, 56.2° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Cattamarra Coal Measures Formation, Toarcian (182.7 - 174.1 Ma)

• group of beds-level stratigraphic resolution

Environment/lithology: interdistributary bay; lithified siltstone

• Due to a lack of flow-indicative sedimentary structures, the Mintaja fossil layer is thought to have been deposited in a quiescent, subaqueous environment with no or little fluvial influence, although the coarse silt grain-size and common, highly fragmented plant material suggests a shallow depth for this water body. A lack of coaly or lignitic layers within the fossil-bearing sediments indicates oxygenated conditions at the sediment–water interface, so that organic material decayed rather than being preserved, preventing any build-up of organic material. This suggests deposition in a shallow pool, as opposed to a mire or swamp. The hypothesized conditions fit well with the overall interpretation of the Cattamarra Coal Measures as a delta-plain deposit, with fine-grained sediments (such as at Mintaja) representing deposition in interdistributary bay environments (Mory, 1994).

Size class: macrofossils

Collected by AJ Mory in 1989; reposited in the WAM

Primary reference: S. K. Martin. 2010. Early Jurassic cockroaches (Blattodea) from the Mintaja insect locality, Western Australia. Alavesia 3:55-72 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 152041: authorized by Matthew Clapham, entered by Matthew Clapham on 03.11.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

 Dicondylia -
Blattodea "clavus sp. 2" Latreille 1810 cockroach
WAM 08.148