Palynology and organic petrology of the Water Park Creek Basin, Queensland

Abstract

Listen

Translate article

The Water Park Creek Basin is one of a number of similar Tertiary basins on the eastern coast of Queensland, Australia. The basin contains a sequence of shales, oil shale, sandstones and coal. One hundred and forty-four samples have been taken from five fully cored wells drilled by Southern Pacific Petroleum to a maximum depth of 488 metres.This study aims to integrate palynology with organic petrology and aspects of sedimentology. Palynological analysis identifies a diverse angiosperm assemblage, trilete, monolete and fungal spores, few gymnosperms, and a single freshwater dinoflagellate species. A total of eighty eight spores and pollen species have been identified, including nine new species and five previously described from the Yaamba Basin, but as yet unpublished. The new species are Cyathidites granulatus, Malvacipollis hrevaculeus, Nothofagidites gliksonii, Polypodiisporites yaambaensis, Propylipollisfalkneri, Proteacidites bolus, Proteacidites wrightii, Retitriletes isodictyus and Triporopollenites byfieldensis.The botanical affinities lie mostly with Australian type palynofloras including Myrtaceidites, Haloragacidites, Nothofagidites and Proteacidites. In addition, there is a significant tropical component, including Crassoretitriletes vanraadshooveni. Five palynozones have been recognised, which strongly correlate to lithological units. Coarsely based, fining upward sandstone sequences have been identified, which together with fine-grained varved units indicating alluvial sedimentation of fluvial and lacustrine origin. The occurrence of a terrestrial palynoflora associated with freshwater algae, including Pediastrum and Botryococcus, the fern Azolla and the dinoflagellate Saeptodinium gravattensis strongly indicates a freshwater depositional environment. Organic petrology reveals maceral components dominated by telocollinite with significant amounts of cutinite and resinite. Inertinite is generally less than 5% of the total organic matter, with funginite the most common submaceral within this group. The vitrinite reflectance ranges between Ro 0.28 and 0.85% There is a strong correlation between vitrinite type and reflectance values.The Water Park Creek Basin contains a spores-pollen flora that most closely resembles that of the middle Nothofagidites asperus Zone, Gippsland Basin (Partridge 1976) thus suggesting a late Eocene age to possibly early Oligocene age.