ABSTRACT
The Narrows Beds are a Tertiary sedimentary sequence containing oil shale seams, which were deposited in a narrow north-northwest-trending graben. The graben is about 24 mi (38 km) long by 3 mi (5 km) wide and is located adjacent to the central Queensland coast. Two similar oil-shale deposits, Rundle and Stuart containing 5.1 billion bbl of shale oil have been defined within the graben.
The Tertiary sedimentary rocks, which were deposited in a freshwater lacustrine environment, are more than 3,280 ft (1,000 m) thick and dip gently westward. They consist of the Worthington beds and the Rundle and Curlew Formations.
The Worthington beds range from conglomerate through sandstone to claystone. The Rundle Formation consists of six kerogenous seams and a claystone unit. The sedimentary rocks are consistent throughout the graben. The Curlew Formation is an interbedded sequence of claystone and minor carbonaceous shale. The Worthington beds and the Rundle Formation have been intruded by olivine dolerite, which is not extensive. Quaternary overburden blankets most of the area. Paleontologic studies indicate an early to late Eocene age for the Rundle and Curlew Formations.
