Where: Tasmania, Australia (42.1° S, 146.7° E: paleocoordinates 54.3° S, 145.9° E)
• coordinate stated in text
When: Upper Proteacidites tuberculatus pollen zone, Late/Upper Oligocene to Late/Upper Oligocene (28.4 - 16.0 Ma)
• The sediments are regarded as probably late Oligocene or early Miocene age based on analysis of microflora and radiometric dates of closely associated basalts (Hill & Gibson, 1986).
•The area has been dated using K-Ar analysis, the age range 23.6-21.8 Myr (Sutherland et al. 1973).These results agree with the palynological data, and an earliest Miocene age is therefore proposed for the Monpeelyata deposit, with the probable age falling within the period 21.8-23.6 Myr (M.K. Macphail, personal communication).
•The age of Monpeelyata is based on a combination of palynological data and K-Ar dates on basalt flows in the area surrounding Great Lake. Both sets of data point to the Monpeelyata flora being no younger than earliest Miocene. The maximum age is less well defined although the absence of a large number of species found in Oligocene palynoflora in northern Tasmania (Hill & Macphail, 1983; Hill, 1987) suggests that the flora is unlikely to be older than the (latest?) Late Oligocene. (Macphail and Hill, 1991)
Environment/lithology: lacustrine; gray mudstone
•Abundant remains of the freshwater hydrophyte Isoetes (Hill, 1988) and the fine grain size of the emergent sedimentary rock indicate a low energy depositional environment, probably a shallow pond, a sluggish river channel, or less likely a shallow, sheltered lake bay, subaerially exposed before or during lava extrusions. (Macphail and Hill, 1991)
•The plant fossils described by Macphail and Hill 1991 come from a mudstone exposed in the west wall of the Monpeelyata Canal which diverts water from the Ouse River into the Lake Echo hydroelectic impoundment. The exposure occurs directly next to the bridge on the Monpeelyata Canal service road. The mudstone lens forms part of a thin (<2 m?) concave lenticular sedimentary sequence that overlies Jurassic dolerite and is overlain by massive to vesicular, alkali olivine basalt. (Macphail and Hill, 1991)
Size classes: macrofossils, microfossils
• Several female cones were retrieved from the mudstone.
Collection methods: bulk, sieve,
Primary reference: R. S. Hill. 1987. Tertiary Isoetes from Tasmania. Alcheringa 12(2):157-162 [C. Jaramillo/C. Jaramillo]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 167314: authorized by Carlos Jaramillo, entered by Carlos Jaramillo on 11.03.2015
Creative Commons license: CC BY (attribution)