Using detrital geochronology to unravel the Proterozoic greater McArthur Basin of Northern Australia

Abstract

<p>There is still little known about the occurrence, formation and spatial distribution of long-lived cratonic basins that form during hundreds of millions of years of subsidence. Their histories often span multiple phases of super-continent break-up, dispersal and amalgamation. Each of these phases resulted in the modification of sedimentation rates and drainage within the basins but the broader basin persisted. These changing conditions are recorded in the detrital zircon record, providing a tool for understanding the basin evolution and consequently its palaeogeography.</p><p>The informally termed greater McArthur Basin is a regionally extensive Proterozoic basin that overlies the North Australian Craton. It is a vast sedimentary system that stretches across the northern part of the Northern Territory from north-eastern Western Australia to north-western Queensland. It includes Palaeo- to Mesoproterozoic successions of the McArthur and Birrindudu basins, the Tomkinson Province and likely the Lawn Hill Platform and South Nicholson Basin (to the south-east); all interpreted to be contemporaneous systems. However, the full extent of the greater McArthur Basin sedimentary system is still being unravelled. The basin records nearly one billion years of Earth history, from ca. 1.82 Ga to ca. 0.85 Ma. This sedimentary system temporally overlaps with episodes of Palaeo- to Mesoproterozoic tectonism and igneous activity that affected underlying and adjacent terranes, including the Aileron, Warumpi and Musgrave provinces to the present-day south, Pine Creek Orogen and Arnhem Province to the north, Halls Creek Orogen and Tanami Region to the west, and Mount Isa and Murphy provinces to the east.  </p><p>LA-ICP-MS detrital zircon U–Pb geochronology and Lu–Hf isotope data provide new constraints on the lower sedimentary successions of the McArthur Basin (Tawallah and Katherine River Groups) and demonstrate they are coetaneous with the Tomkinson Province (Tomkinson Creek Group). U–Pb detrital zircon data show major <sup>207</sup>Pb /<sup>206</sup>Pb peaks at ca. 1860 Ma and ca. 2500–2400 Ma in both the McArthur Basin and Tomkinson Province sediments. Combined with Lu–Hf isotope data, the detrital zircon age data from the McArthur Basin show similarities to the Aileron Province (to the south) and magmatic rocks of the Gawler Craton, suggesting that these terranes might be possible source areas. Comparatively, the oldest succession within the Tomkinson Province (Hayward Creek Formation), shows similar spectra to units within the Lawn Hill Platform succession (McNamara Group, Surprise Creek Sandstone and Carrara Range Group) possibly suggesting a correlation between the two areas.</p><p>Here we explore the links between the North Australia Craton and surrounding continents to further elucidate the evolution of this enigmatic basin throughout the Proterozoic. New palaeogeographic reconstructions link the ‘greater’ McArthur basin to the Yanliao Basin and coeval rocks in the North China Craton. The ‘greater’ McArthur basin may also have extended into southern Australia, Laurentia and Siberia as a vast intra-continental gulf (the McArthur-Yanliao Gulf) within the core of the supercontinent Nuna/Colombia.</p>