Evolution of the depositional environments of the Jurassic Walloon Coal Measures, Surat Basin, Queensland, Australia

Abstract

The Jurassic Walloon Coal Measures of the Surat Basin in eastern Australia host the continent's most significant coal bed methane resources. Previous studies have interpreted the Walloon Coal Measures within a single depositional facies model encompassing a wholly terrestrial setting. Using a multidisciplinary approach (facies analysis, palynology and wireline logs), the evolution of the Walloon Coal Measures is described within a new chronostratigraphic framework defined by accurate and precise U-Pb tuff dates. Analysis of sedimentary facies indicates that the majority of the Walloon Coal Measures was deposited by relatively small (<300 m wide), low gradient rivers on a poorly-drained floodplain with numerous small lakes and mires. However, this study also identified some marine-influenced facies with brackish palynomorphs (notably dinoflagellate cysts) and tidal sedimentary structures. These facies appear to have been deposited in estuaries during times of transgression. The evidence for base level shifts suggests that the coals may not have coevally accumulated with at least some of the thicker sandstones. Palaeogeographic maps for eleven time intervals suggest that rivers drained towards to the south/south-west and south-east, as indicated by sandstone percentage and gross unit isopach maps, presumably into proximal estuarine complexes. Marine incursions into the continent probably came from the north and east during times of high eustatic sea level and as precursors to those of the more persistent and extensive transgressions of the Early Cretaceous. A similar multidisciplinary approach should help to elucidate the evolution of other fluviolacustrine systems in other basins and aid in resource prediction.

Sustainability of beef production from brigalow lands after cultivation and mining. 3. Pasture rundown, climate and grazing pressure effects

“…The depth of soil covering the mine spoil in the rehab paddocks was variable (45 AE 30 cm) and these paddocks were modelled as two layers of soil and the third layer as mine spoil with the texture of light clay containing 40% rock fragments. The mine spoil should be a potentially useful contributor to soil water storage and plant growth because it is a labile argillaceous material of medium to very fine-grained sandstone derived from volcanic fragments with a high proportion of pore space filled by smectite clays (Wainman and McCabe 2019). It was explored by plant roots, is moderately alkaline (pH 8.3), has a high cation exchange capacity and the salinity, sodicity and toxicity levels were of no concern (Bennett et al 2021).…”

“…The study area forms part of the Acland Land System (Vandersee 1975) of the Brigalow Region and has a mean annual rainfall of 642 mm. Local soils, typically Dermosols and Vertosols (Isbell 2002) are derived from the underlying labile fine-grained sandstone of the Walloon Coal Measures (Wainman and McCabe 2019), or overlying tertiary basalt flows (Vandersee 1975). The soils are suited to grazing but most are marginal for cropping because of susceptibility to erosion, sodic subsoils and shallow depths that limit soil water availability.…”

Deciphering Late Cretaceous palaeo‐river catchments in eastern Australia: Recognition of distinct northern and southern drainage basins

“…The logging and sampling of each of these cores were conducted at the Geological Survey of Queensland (GSQ) core facility located at the Exploration Data Centre in Brisbane, Queensland, Australia. The facies analysis scheme utilised on GSQ Dobbyn 1 (Figure 4), GSQ Normanton 1 (Figure S1) and GSQ Rutland Plains 1 (Figure S2) follows the framework of Wainman and McCabe (2019) and Foley, Roberts, et al (2021), employing colour codes to denote seven individual sedimentary facies, and subsequently grouping these to create three facies associations (FAs) (Tables 1 and 2). Delhi‐Santos Mornington Island 1 was not logged as only a short interval (ca.…”

“…The reconstruction of ancient depositional systems and their associated basinal palaeodrainage patterns from the rock record can be challenging, particularly in areas of little or no outcrop exposure (e.g. Blum et al, 2017; Helland‐Hansen et al, 1992; Horner et al, 2019; Wainman & McCabe, 2019). Such cases usually require the integration of voluminous datasets including core‐based sedimentary facies analysis, geophysical (seismic) and petrophysical (wireline log) data and sandstone petrography (e.g.…”

Evolution of depositional environment of the Pliensbachian Stage (Lower Jurassic) coal‐bearing series in the Qaidam Basin, NW China

“…The research on sedimentary characteristics and depositional evolution of coal‐bearing series in terrestrial lacustrine basins has drawn worldwide attention in recent years (Basu et al, 2021; Benayad et al, 2019; Chen et al, 2022; Hou et al, 2023; Lu et al, 2020a; Wainman & McCabe, 2019; Xia et al, 2018, 2019, 2020; Yue et al, 2018). The Qaidam Basin, located in the eastern margin of the Qinghai‐Tibet Plateau, is a typical Mesozoic–Cenozoic basin and covers 150,000 km 2 between latitudes 36° N–39° N and longitudes 91° E–98° E. The Lower–Middle Jurassic rocks at the Qaidam Basin have been proven to be an important succession for hydrocarbon exploration and development (Cao et al, 2012; Hou et al, 2022; Liu et al, 2018; Ritts et al, 1999; Tian et al, 2018; Wang et al, 2005; Yang et al, 2004).…”