Basin history

Extensional tectonism in the Late Carboniferous initiated formation of the Koburra Trough, and resulted in the deposition of Lake Galilee Sandstone (Van Heeswijck, 2010). This was followed by deposition of the Jericho Formation in the Koburra Trough and the southern Galilee Basin.

By the Early Permian, sedimentation had become more widespread with deposition of the Jochmus Formation across the northern Galilee Basin and the Lovelle Depression. At the same time the Boonderoo beds were deposited around the north-eastern margin of Galilee Basin. The Aramac Coal Measures were formed west of the Koburra Trough and in the Lovelle Depression during the latter stages of deposition of the Jochmus Formation. Minor uplift and faulting took place along pre-existing structures near the eastern margin of the Galilee Basin, towards the end of Early Permian sedimentation (Van Heeswijck, 2010). A significant erosional-non depositional event occurred across the Galilee Basin during the Early to Late Permian.

Sedimentation recommenced in the Late Permian with the deposition of coal-rich Betts Creek beds and its correlatives to the south, the Colinlea Sandstone - Bandanna Formation sequence. In the Early to Middle Triassic this was followed by deposition of the Rewan and Clematis groups and their lateral equivalent in the north-eastern Galilee Basin, the Warang Sandstone. The Moolayember Formation was the final sedimentary unit deposited in the Galilee Basin.

By the end of the Hunter-Bowen Orogeny in the Middle Triassic, sedimentation in the Galilee Basin ceased. This was accompanied by inversion of eastern Galilee Basin margin with reactivation of pre-existing structures (McKellar and Henderson, 2013). I’Anson (2013) suggests that in the Middle Triassic to Middle Jurassic, the amount of Galilee Basin sedimentary sequence that was eroded away was less than 600 m thick.

In the Galilee subregion, sediment deposition in the Eromanga Basin commenced in the Middle Jurassic. Here, the Ronlow beds and their equivalents, the Hutton Sandstone to Hooray Sandstone, and the Cadna-owie Formation, comprise the basal sequences of the Eromanga Basin. With the exception of the Cadna-owie Formation, these sequences were deposited in fluvial-lacustrine or braided fluvial environments. The Lower Cretaceous Cadna-owie Formation was deposited in marginal marine environments, which marked the onset of a major marine transgression across the Eromanga Basin.

Deep marine environments existed throughout much of the Early Cretaceous until the deposition of the Makunda Formation, which formed in shallow marine settings as sea levels regressed across the Eromanga Basin. The Winton Formation heralds the return of continental fluvial deltaic depositional environments in the Eromanga Basin. Deposition of the Winton Formation ceased in the earliest stages of the Late Cretaceous.

Extensive planation and deep weathering of the Late Cretaceous Eromanga Basin surface continued into the Paleocene with formation of the Morney weathering profile, which can be up to 95 m deep and is characterised by kaolinite, ferricrete, mottling, capped by the Curalle silcrete. I’Anson (2013) suggests that during this time, the thickness of sedimentary sequence that was eroded away varied from 500 to 1900 m across the Galilee Basin region.

At the beginning of the Cenozoic, Queensland was emergent above sea level and in a relatively passive extensional tectonic regime with a low-lying plain west of the Eastern Highlands. This period is characterised by shallow isolated basins produced by mild regional deformation (Jell, 2013). Three broad Cenozoic cycles of uplift, erosion and deposition with intervening landscape stability and deep weathering are recognised west of the Eastern Highlands.

A Late Paleocene to Early Eocene depositional hiatus marks the onset of a new cycle of tectonic activity and the end of an extension regime for eastern Australia and Papua New Guinea. Geological structures in the Eromanga and Galilee basins were reactivated and in places Eromanga Basin rocks were faulted and deformed into a series of folds (McKellar and Draper, 2013). During this time, warping and erosion of the Morney Profile occurred with deposition of fluvial siliciclastic sediments in some isolated depositional centres and as broader sheets of quartz sandstone, pebble conglomerate, sandy conglomerate and subordinate siltstone and mudstone across the Lake Eyre surface drainage catchment.

By the end of the Eocene, tectonic activity waned and planation occurred across the basin which was accompanied by deep weathering and the formation of silcrete and ferricrete. These erosive and deep weathering events resulted in the development of the Featherby Surface and the Canaway Profile. The Oligocene to Early Miocene Canaway Profile consists of up to a 50 m deep weathering profile capped by the Cordillo silcrete.

In the Late Oligocene, subsidence along the north-eastern continental margin was associated with north-south compression in western Queensland, which modified the small regional Paleogene basins and gently warped their sediments, weathering profiles and duricrusts. During the Miocene, a second succession of sedimentation, in part derived from earlier Paleogene sediments, was initiated and resulted in the deposition of sedimentary sequences such as the Whitula Formation (Jell, 2013).

The Late Miocene conclusion of this second depositional cycle and associated planation and weathering events are not well defined in the region. From the Late Miocene, western Queensland was relatively stable, and well-weathered colluvial and channel and floodplain fluvial sediments were deposited as gentle Pliocene uplift and warping occurred (Cook, 2013). The Sturgeon Basalt erupted near Hughenden in the Pliocene to Pleistocene.

Post-Miocene duricrust stratigraphy is less well understood within the region although some Pliocene silcrete has been described. Gypcretes began to form as the paleoclimate trended towards greater aridity in the Pliocene and Quaternary (Cook, 2013).

The Quaternary has been dominated by the repetitive global glacial-interglacial temperature oscillations, driven by Milankovitch orbital insolation cycles. In western Queensland, far from sites of glaciation, these cycles have seen oscillation from warm, wetter interglacials with enhanced monsoon rainfall, runoff and fluvial and lacustrine deposition to cool dry glacials with reduced monsoon and enhanced aeolian sedimentation (Price, 2013).

Most of the Galilee Basin is covered by the Lake Eyre drainage catchment, which includes channel country river systems of the Diamantina and Cooper. Deposition in these fluvial systems has probably been episodically continuous through the Quaternary. However, a lack of significant subsidence and subsequent accommodation space is likely to have caused horizontal separation of successive fluvial phases, resulting in lateral erosion and reworking of earlier Quaternary fluvial sediments. Fluvial deposits from the most recent (Holocene) interglacial and the two previous interglacials have been extensively studied and dated (Nanson et al., 1992; Maroulis et al., 2007; Nanson et al., 2008). These studies show that discharge during successive interglacial episodes declined markedly, indicating either a progressive waning in monsoon intensity or some other switching of the precipitation moisture source (Nanson et al., 2008). Studies of Late Pleistocene paleo-channels suggest that discharges from the Cooper Creek paleo-stream were up to seven times larger than present day volumes.

The eastern margin of the Galilee Basin is covered by the headwaters of the large coastal catchments of the Fitzroy and Burdekin rivers where they are probably incisional. Sediments of these systems are poorly studied, though initial dating of fluvial sediments down catchment from the Galilee subregion in the Fitzroy surface drainage catchment suggests a similar chronology to the Lake Eyre channel country rivers (Croke et al., 2011). At the southern margin of the Galilee Basin are the upper catchments of the Bulloo River system and the Warrego River of the Murray–Darling Basin, both of which are poorly studied and undated. At the north-western margin of the Galilee Basin is the upper catchment of the Flinders River, which flows north-westerly to the Gulf of Carpentaria and is also poorly studied and undated.

Lake Buchanan is a playa lake near the eastern margin of the Galilee subregion that lies astride the Eastern Highlands in a closed intermontane depression between the upper catchments of the Cooper Creek and Burdekin River systems (Chivas et al., 1986). A 15 m core from the lake indicates uniform non-laminated sandy clay sediments. There are no occurrences of primary or chemically precipitated gypsum or carbonate. Paleomagnetic reversal dating returned an age of 0.781 Ma (Middle Pleistocene) at 5.0 m and an extrapolated age of between 1.5 and 2 Ma at 15 m depth. A total of 13 dry episodes, as indicated by paleosols, are evident in the core and four major wet phases are recorded in the Middle and Late Pleistocene (Chivas et al., 1986).

Last updated:
5 January 2018