Fig. 1. Major geological, biological and environmental events related to development of the Transgondwanan Supermountain and Gondwana Super-fan System during the late Neoproterozoic to Ordovician interval. Cross-hatched boxes represent the timing and duration of collisional orogenesis associated with diachronous East–West Gondwana convergence [5] and [60] (highlighted by the large arrow). The intervals recording the greatest flux of quartz-rich sediment associated with the Gondwana Super-fan System are stippled in blue, whereas those with lower depositional rates are shown in grey; dashed lines during the Ediacaran period indicate that the depositional rates are inferred (i.e., sedimentary units not preserved). Remaining data are from the following sources: major episodes of Neoproterozoic glaciation [4], [20] and [90]; Sr-isotope values for seawater [9] and [12]; carbon isotope values for carbonate [2] and [18], diversity of genera [2]; and episode of rapid plate motion [79]; N–D, Nemakit–Daldynian; To, Tommotian; A, Atdabanian; B, Botoman; T, Toyonian; Mid, Middle.

Fig. 2. Simplified location maps. (a) Pre-Jurassic configuration of East and West Gondwana, showing the main tectonic elements and known distribution of early Palaeozoic quartz-rich sedimentary units [6], [7], [33], [37], [51] and [52]. (b) Simplified geological map of the western Lachlan and eastern Delamerian orogens in southeastern Australia [7] showing the distribution of the main early Palaeozoic units and the location of detrital-zircon samples analysed for this study.

Fig. 3. Time-versus-space chart showing the distribution and stratigraphic relationships of the Cambrian to Early Devonian quartz-rich successions in East Gondwana (i.e., India [51], Australia [7] and [45], New Zealand [42], Antarctica [7], [37], [41] and [49], South Africa [50] and northern Patagonia [52]. The stratigraphic position of detrital-zircon samples discussed is shown. Modified after Squire and Wilson [7]. Tas., Tasmania; N.Z., New Zealand; S., South; Amer., America; Delamer., Delamerian; Gramps., Grampian; Melb., Melbourne; Transant., Transantarctic; Mount., Mountain.

Fig. 4. Summary of the detrital-zircon components from East Gondwana. Detrital-zircon U/Pb age spectra for quartz-rich sandstones from this and previous studies (A [32], B [51], C [41], D [53], E [42], F [49] and G [54]). n, number of analyses.

Fig. 5. A schematic reconstruction showing the major features associated with evolution of the Transgondwanan Supermountain and Gondwana Super-fan System. (a–d) Oblique convergence between East and West Gondwana from  650 and 515 Ma resulted in the establishment of an enormous mountain chain (Transgondwanan Supermountain). The Gondwana Super-fan System developed as a result of this collisional event and tectonic events along the proto-Pacific margin of East Gondwana (see Ref. [7]). Deposition associated with the super-fan system lasted for at least 260 Myr. The present-day areal extent of the Bengal and Nicobar fans [36], are shown in black for scale. Palaeogeography of the continents are modified after Kirschvink et al. [3].