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| | | East Pilbara Terrane Rifting Event (PCR) | AH Hickman | | | | | Event type | tectonic: continental breakup | Parent event | | Child events | | Tectonic units affected | | Tectonic setting | basin: continental rift | Metamorphic facies | | Metamorphic/tectonic features | –– |
| | | Summary | The 3280–3165 Ma East Pilbara Terrane Rifting Event included the breakup of the Paleoarchean volcanic plateau of the Pilbara Craton. An interpreted cause of the event was the arrival of a large mantle plume beneath the Pilbara Craton that led to the volcanic succession of the Sulphur Springs Group and to widespread intrusion of the Cleland Supersuite. Crustal extension above the plume resulted in normal faulting and increasing rifting during deposition of the Sulphur Springs Group. By c. 3235 Ma rifting had increased to the point that mantle-tapping fractures allowed the intrusion of ultramafic–mafic dykes from the mantle. Between c. 3220 and 3200 Ma two rift basins opened up, one in the northwestern Pilbara between the present Tabba Tabba and Sholl Shear Zones and the other along the axis of what is now the Mosquito Creek Basin. Other rift basins are likely to have developed outside the preserved area of the Pilbara Craton.
The Tabba Tabba – Sholl rift system evolved into the basaltic Regal Basin lacking any underlying continental crust. The continental microplates either side of the Regal Basin were the Karratha Terrane and the East Pilbara Terrane. In the east Pilbara, the Mosquito Creek Basin separated the East Pilbara and Kurrana Terranes. Clastic passive margin basins formed on the margins of the three continental microplates. The Soanesville Basin evolved along the northwestern margin of the East Pilbara Terrane and the Nickol River Basin formed on the southeastern Formation. Plate collision recorded by the c. 3165 Ma Karratha Event halted expansion of the Regal Basin. margin of the Karratha Terrane. The Budjan Creek Formation was deposited on the southeastern margin of the East Pilbara Terrane and the Coondamar Formation was deposited in the Mosquito Creek Basin. In the Soanesville Basin, clastic deposition was replaced by basaltic volcanism at c. 3185 Ma and similar volcanic activity is recorded in the succession of the Coondamar. | | | Distribution | Evidence of the event is preserved across the entire area of the northern Pilbara Craton. Notable results of the event include the present separation of the East Pilbara, Karratha and Kurrana Terranes, the Mesoarchean passive margin successions (Soanesville Group, Nickol River Formation, Budjan Creek Formation and Coondamar Formation) and the extensive obducted remnants of the Regal Formation in the northwestern Pilbara (Hickman, 2001). The Kurrana Terrane, including the Billinooka, Cooninia, Rat Hill, Rooney and Springer Inliers would also have been affected by the East Pilbara Terrane Rifting Event due to its proximity to the rifted Mosquito Creek Basin.
Major structures that originated during the East Pilbara Terrane Rifting Event include the Sholl Shear Zone and the Loudens Fault in the northwestern Pilbara, the Tabba Tabba Shear Zone between the Central Pilbara Tectonic Zone and the East Pilbara Terrane, the Lalla Rookh – Western Shaw Structural Corridor, the Coongan – Warralong Fault Zone and the Kurrana Shear Zone. Additionally, the Mount Billroth Supersuite, which intruded along the northern margin of the Kurrana Terrane and close to the northwestern margin of the East Pilbara Terrane, is likely to have been the product of convergence-related melting of juvenile basaltic crust in the Mosquito Creek and Regal Basins. | | | Description | The 3280–3165 Ma East Pilbara Terrane Rifting Event (Hickman, 2016) refers to all the tectonic processes involved in the breakup of the Paleoarchean volcanic plateau of the Pilbara Craton. Until the end of the 3325–3290 Ma Emu Pool Event, the plateau had evolved by successive episodes of plume-related volcanic eruptions over a period of 240 Ma. By 3290 Ma, a 15 km-thick volcanic succession had been deposited on Eoarchean to early Paleoarchean continental crust. The total thickness of the Pilbara crust at this stage was probably at least 40 km and was laterally heterogeneous, including locally thick felsic sections. Resulting gravity-driven vertical deformation established a dome–and–keel crustal architecture.
The East Pilbara Terrane Rifting Event marked a major change in the crustal evolution of the Pilbara Craton. Paleoarchean mantle plume activity and vertical deformation gave way to the Mesoarchean thick sedimentary basins and horizontal deformation. Paleoarchean melts derived from crustal recycling of much older crust were succeeded by Mesoarchean juvenile, mantle-derived melts. This event marked the beginning of plate tectonic processes in the Pilbara Craton.
The East Pilbara Terrane Rifting Event developed in three main stages:
1. 3280–3223 Ma deposition of the Sulphur Springs Group and intrusion of the Cleland Supersuite. This stage was marked by increasing crustal extension above the Sulphur Springs mantle plume. Following uplift of the East Pilbara Terrane during the Emu Pool Event, rapid erosion resulted in clastic deposition of the Leilira Formation. At c. 3275 Ma, plume-related volcanism commenced with eruption of the ultramafic–mafic Kunagunarrina Formation followed by mafic–felsic volcanism of the Kangaroo Caves Formation. Granitic intrusion of the Cleland Supersuite accompanied felsic volcanism of the Kangaroo Caves Formation. Crustal extension increased with time, being particularly evident at c. 3235 Ma (Vearncombe et al., 1995, 1998; Buick et al., 2002) at which time deep rifting of the Pilbara crust also led to intrusion of ultramafic–mafic sills and dykes.
2. 3223–3200 Ma continental breakup of the Paleoarchean Pilbara Craton is best represented by the East Pilbara Terrane. At least three plates of continental crust (East Pilbara, Karratha and Kurrana Terranes) commenced separation (Hickman, 2001, 2016; Van Kranendonk et al., 2002, 2007, 2010; Hickman et al., 2010). Other plates, possibly including crust of the south Pilbara Craton and the much larger plate of the east Kaapvaal Craton, might also have separated at this time. Rift basins of oceanic-like basaltic crust formed between the separating continental plates. The best preserved evidence of this stage in the Pilbara Craton is provided by the juvenile basaltic crust of the 3200–3160 Ma Regal Formation (Sun and Hickman, 1998, 1999). This formation was deposited between the East Pilbara and Karratha Terranes (Van Kranendonk et al., 2006; Hickman, 2016).
3. 3223–3165 Ma evolution of passive margin basins along the margins of the continental plates. Clastic sedimentary basins, such as the Soanesville and Nickol River Basins formed above the still extending crust of the continental margins (Van Kranendonk et al., 2006, 2007; Hickman et al., 2010; Hickman, 2012, 2016, 2021). At c. 3185 Ma, clastic sedimentation in the Soanesville Basin was followed by eruption of basaltic volcanic rocks (Honeyeater Basalt) and intrusion of ultramafic–mafic sills and dykes (Dalton Suite). In this basin, volcanism increased northwest towards the eastern margin of the Regal Basin. In the Mosquito Creek Basin, clastic sedimentation of the Budjan Creek Formation (Eriksson, 1981; Bagas et al., 2004) was followed by mixed sedimentary and volcanic deposition of the Coondamar Formation (Bagas, 2005; Farrell, 2006).
At c. 3165 Ma, separation of the Karratha and East Pilbara Terranes was halted during the Karratha Event, but other plates produced by the breakup probably had different histories. For example, separation of the Kurrana and East Pilbara Terranes forming the Mosquito Creek Basin probably ceased between c. 3199 and 3178 Ma because the tonalite–trondhjemite–granodiorite (TTG) protolith of the Golden Eagle Orthogneiss was most likely having been intruded during convergence and melting of juvenile crust in the c. 3200 Ma Mosquito Creek rift basin. | | | | | | Geochronology | | | East Pilbara Terrane Rifting Event | Maximum age | Minimum age | Age (Ma) | 3280 | 3165 | Age | Paleoarchean | Mesoarchean | Age data type | Inferred | | References | | |
| The event is inferred to have commenced at the same time as deposition of the Sulphur Springs Group at c. 3280 Ma. This timing is interpreted to coincide with the arrival of the mantle plume that resulted in the eruption of the volcanic formations of the group. The Sulphur Springs Group was deposited after the 3325–3290 Ma Emu Pool Event, the age which is well-defined by U–Pb zircon dating of granites of the Emu Pool Supersuite. In the Yilgalong Dome of the East Pilbara Terrane, a felsic dyke dated at 3279 ± 4 Ma (GSWA 178007, Nelson, 2005) is likely to have been the first intrusion related to the mantle plume.
The end of the event coincided with final volcanism of the Soanesville Group and intrusion of the Flat Rocks Tonalite dated at c. 3165 Ma. Two dates were obtained on this tonalite: 3164 ± 4 Ma (GSWA 142946, Nelson, 2000a) and 3166 ± 5 Ma (GSWA 142948, Nelson, 2000b). This timing is similar to that of a metamorphic event at c. 3160 Ma (Karratha Event) that coincided with the end of plate separation between the Karratha and East Pilbara Terranes. Metamorphism of the Karratha Event was initially dated at 3160 ± 158 Ma (K−Ar, hornblende) by Kiyokawa (1993), and subsequently at 3144 ± 35 Ma (⁴⁰Ar/³⁹Ar age) by Beintema (2003). Additional evidence for this metamorphic event was provided by 3156 ± 4 Ma and 3152 ± 5 Ma dates on zircons from a c. 3265 Ma granodiorite (JS43, Smith et al., 1998). Smith et al. (1998) interpreted this c. 3155 Ma age to be the result of thermotectonic resetting during an event of deformation and metamorphism. | | | Tectonic Setting | The continental breakup of the Paleoarchean Pilbara Craton at c. 3220 to 3200 Ma followed a period of increasing crustal extension and rifting commencing at c. 3280 Ma. The timing of the crustal extension coincided with the arrival of the Sulphur Springs mantle plume beneath the Pilbara crust, and continental breakups are frequently attributed to uplift and extension above mantle plumes (Storey, 1995; Condie, 2005; Ernst, 2014). The regional extent of the Sulphur Springs plume is established from outcrops of the Cleland Supersuite as far apart as the Karratha Terrane in the northwestern Pilbara and the Yilgalong Dome in the far east of the East Pilbara Terrane. Outside the northern Pilbara Craton, several large granitic intrusions dated at c. 3230 Ma are present in the east Kaapvaal Craton of southern Africa (Van Kranendonk et al., 2015).
At 3280 Ma the Pilbara crust is likely to have been well over 40 km thick (Van Kranendonk, 2000). Evidence for this crustal thickness includes: 1, the preserved >15 km total stratigraphic thickness of the Warrawoona and Kelly Groups; 2, an estimated 10–15 km minimum total thickness of Paleoarchean granitic supersuites underlying and intruded into the supracrustal succession; 3, an inferred >15 km thickness of pre-Warrawoona Group sialic crust; and 4, modelling based on the formation of the dome-and-keel crustal architecture of the terrane (Van Kranendonk, 2000). From the first eruption of the Warrawoona Group at c. 3530 Ma, progressive thickening of continental crust over 250 Ma would have increased temperatures in the crust and upper mantle due to insulation of conductive heat from the mantle and of radiogenic heat from mid-crustal granites (Sandiford et al., 2004; Van Kranendonk, 2011). Rising temperatures would have weakened the crust, increasing the probability of uplift, extension and rifting above the Sulphur Springs plume.
Deep rifting and of the Pilbara crust at c. 3220 Ma led to the development of two basaltic rift basins (Regal and Mosquito Creek Basins) between three separating continental microplates (Karratha, East Pilbara and Kurrana Terranes). A rift system also formed in the central part of the east Pilbara Terrane, along the present trend of the Lalla Rookh – Western Shaw Structural Corridor. However, basaltic volcanism did not take place in this fault zone until c. 3185 Ma and then was not confined to the rift zone. Crustal extension continued until c. 3165 Ma in the case of the Regal Basin, but only until c. 3200 Ma in the Mosquito Creek Basin. Mantle plume activity ceased at c. 3223 Ma, probably in response to rapid cooling of the crust due to heat loss, resulting from the basaltic volcanism.
The East Pilbara Terrane Rifting Event was of major tectonic significance in the crustal evolution of the Pilbara Craton. For 250 Ma prior to the event, the Pilbara Craton had evolved through plume-related igneous activity and episodes and gravity-driven vertical deformation. From c. 3220 Ma onwards, deposition was dominated by sedimentation in large sedimentary basins and involved plate tectonic processes, such as subduction, obduction, and terrane and basin accretion. Whereas Paleoarchean melts were mainly derived from reworking of much older crust, most Mesoarchean melts were derived from far more juvenile sources.
This change has important implications for the mineral prospectivity of the Pilbara Craton. Although Paleoarchean mineralization is extremely varied, none of the deposits are large by international or Australian standards (Barley and Groves, 1984; Groves and Batt, 1984; Groves et al., 1984; Barley et al., 1992; Witt et al., 1998; Huston et al., 2001, 2017). The likely explanation is that hydrothermal fluids generated during vertical recycling of continental crust had restricted metal sources. This contrasts with Phanerozoic-style plate tectonic settings, which have the potential for repeated influxes of metal-charged juvenile material, either above subducting slabs or along major strike-slip faults. | | | | References | Bagas, L 2005, Geology of the Nullagine 1:100 000 sheet: Geological Survey of Western Australia, 1:100 000 Geological Series Explanatory Notes, 33p. View Reference | Bagas, L, Farrell, TR and Nelson, DR 2004, The age and provenance of the Mosquito Creek Formation, in Geological Survey of Western Australia Annual Review 2003–04 edited by Geological Survey of Western Australia, Perth, Western Australia, p. 62–70. View Reference | Barley, ME and Groves, DI 1984, Constraints on mineralization of the Warrawoona Group, in Archaean and Proterozoic basins of the Pilbara, Western Australia: Evolution and mineralization potential edited by Muhling, JR, Groves, DI and Blake, TS: The University of Western Australia, Geology Department and University Extension, Publication no. 9, p. 54–67. | Barley, ME, Groves, DI and Blake, TS 1992, Archaean metal deposits related to tectonics: Evidence from Western Australia, in The Archaean: Terrains, processes and metallogeny: Proceedings for the Third International Archaean Symposium, 17–21 September 1990 edited by Glover, JE and Ho, SE: Geology Department and University Extension, The University of Western Australia, Perth, Western Australia, Publication 22, p. 307–324. | Beintema, KA 2003, Geodynamic evolution of the west and central Pilbara Craton: A mid-Archean active continental margin: Geologica Ultraiectina, Utrecht University, Utrecht, The Netherlands, PhD thesis (unpublished), 248p. | Buick, R, Brauhart, CW, Morant, P, Thornett, JR, Maniw, JG, Archibald, NJ, Doepel, MG, Fletcher, IR, Pickard, AL, Smith, JB, Barley, ME, McNaughton, NJ and Groves, DI 2002, Geochronology and stratigraphic relationships of the Sulphur Springs Group and Strelley Granite: a temporally distinct igneous province in the Archean Pilbara Craton, Australia: Precambrian Research, v. 114, p. 87–120. | Condie, KC 2005, Earth as an evolving planetary system: Academic Press, Burlington, Massachusetts, USA, 150p. | Eriksson, KA 1981, Archaean platform-to-trough sedimentation, East Pilbara Block, Australia, in Archaean Geology: Second International Symposium, Perth 1980 edited by Glover, JE and Groves, DI: Geological Society of Australia, Special Publication 7, p. 235–244. | Ernst, RE 2014, Large igneous provinces: Cambridge University Press, Cambridge, UK, 653p. | Farrell, TR 2006, Geology of the Eastern Creek 1:100 000 sheet: Geological Survey of Western Australia, 1:100 000 Geological Series Explanatory Notes, 33p. View Reference | Groves, DI and Blatt, WD 1984, Spatial and temporal variations of Archaean metallogenic associations in terms of evolution of granitoid–greenstone terrains with particular emphasis on the Western Australian Shield, in Archaean geochemistry edited by Kröner, A, Hanson, GN and Goodwin, AM: Spinger-Verlag, Berlin, Germany, p. 73–98. | Groves, DI, Phillips, GN, Ho, SE, Henderson, CA, Clark, ME and Woad, GM 1984, Controls on distribution of Archaean hydrothermal gold deposits in Western Australia, in The geology, geochemistry and genesis of gold deposits edited by Foster, RP: Gold '82, Harare, Zimbabwe, 24–28 May 1982: A. A. Balkema, Rotterdam, The Netherlands; Geological Society of Zimbabwe, Special Publication 1, p. 689–712. | Hickman, AH 2001, Geology of the Dampier 1:100 000 sheet: Geological Survey of Western Australia, 1:100 000 Geological Series Explanatory Notes, 39p. View Reference | Hickman, AH 2012, Review of the Pilbara Craton and Fortescue Basin, Western Australia: Crustal evolution providing environments for early life: Island Arc, v. 21, p. 1–31. | Hickman, AH 2016, Northwest Pilbara Craton: A record of 450 million years in the growth of Archean continental crust: Geological Survey of Western Australia, Report 160, 104p. View Reference | Hickman, AH 2021, East Pilbara Craton: a record of one billion years in the growth of Archean continental crust: Geological Survey of Western Australia, Report 143, 187p. View Reference | Hickman, AH, Smithies, RH and Tyler, IM 2010, Evolution of active plate margins: West Pilbara Superterrane, De Grey Superbasin, and the Fortescue and Hamersley Basins — a field guide: Geological Survey of Western Australia, Record 2010/3, 74p. View Reference | Huston, DL, Blewett, RS, Mernagh, TP, Sun, S-S and Kamprad, J 2001, Gold deposits of the Pilbara Craton: Australian Geological Survey Organisation (Geoscience Australia), Record 2001/10, 86p. | Huston, DL, Wyche, NL, Hickman, AH and Norman, M 2017, Pilbara Craton geology and metallogeny, in Australian ore deposits (6) edited by Phillips, GN: Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, Monograph 32, p. 325–330. | Kiyokawa, S 1993, Stratigraphy and structural evolution of a Middle Archean greenstone belt, northwestern Pilbara Craton, Australia: University of Tokyo, PhD thesis (unpublished). | Nelson, DR 2000a, 142946.1: foliated biotite tonalite, Flat Rocks; Geochronology Record 297: Geological Survey of Western Australia, <www.dmpe.wa.gov.au/geochron>. View Reference | Nelson, DR 2000b, 142948.1: tonalite, Flat Rocks; Geochronology Record 298: Geological Survey of Western Australia, <www.dmpe.wa.gov.au/geochron>. View Reference | Nelson, DR 2005, 178007.1: feldspar–quartz porphyry, Mount Elsie; Geochronology Record 547: Geological Survey of Western Australia, <www.dmpe.wa.gov.au/geochron>. View Reference | Sandiford, M, Van Kranendonk, MJ and Bodorkos, S 2004, Conductive incubation and the origin of dome-and-keel structure in Archean granite–greenstone terrains: A model based on the eastern Pilbara Craton, Western Australia: Tectonics, v. 23, no. 1, doi:10.1029/2002TC001452. | Smith, JB, Barley, ME, Groves, DI, Krapež, B, McNaughton, NJ, Bickle, MJ and Chapman, HJ 1998, The Sholl Shear Zone, West Pilbara; evidence for a domain boundary structure from integrated tectonostratigraphic analysis, SHRIMP U–Pb dating and isotopic and geochemical data of granitoids: Precambrian Research, v. 88, p. 143–172. | Storey, M 1995, The role of mantle plumes in continental breakup: case histories from Gondwanaland: Nature, v. 377, p. 301–308. | Sun, S-S and Hickman, AH 1998, New Nd-isotopic and geochemical data from the west Pilbara — implications for Archaean crustal accretion and shear zone development: Australian Geological Survey Organisation, Research Newsletter, no. 28, p. 25–29. | Sun, S-S and Hickman, AH 1999, Geochemical characteristics of ca 3.0-Ga Cleaverville greenstones and later mafic dykes, west Pilbara: implication for Archaean crustal accretion: Australian Geological Survey Organisation, Research Newsletter, no. 31, p. 23–29. | Van Kranendonk, MJ 2000, Evidence of thick Archaean crust in the East Pilbara, in GSWA 2000 extended abstracts: geological data for WA explorers in the new millennium: Geological Survey of Western Australia, Record 2000/8, p. 1–3. View Reference | Van Kranendonk, MJ 2011, Cool greenstone drips and the role of partial convective overturn in Barberton greenstone belt evolution: Journal of African Earth Sciences, v. 60, no. 5, p. 346–352, doi:10.1016/j.jafrearsci.2011.03.012. | Van Kranendonk, MJ, Hickman, AH, Smithies, RH, Nelson, DN and Pike, G 2002, Geology and tectonic evolution of the Archaean North Pilbara terrain, Pilbara Craton, Western Australia: Economic Geology, v. 97, p. 695–732, doi:10.2113/gsecongeo.97.4.695. | Van Kranendonk, MJ, Hickman, AH, Smithies, RH, Williams, IR, Bagas, L and Farrell, TR 2006, Revised lithostratigraphy of Archean supracrustal and intrusive rocks in the northern Pilbara Craton, Western Australia: Geological Survey of Western Australia, Record 2006/15, 57p. View Reference | Van Kranendonk, MJ, Smithies, RH, Griffin, WL, Huston, DL, Hickman, AH, Champion, DC, Anhaeusser, CR and Pirajno, F 2015, Making it thick: a volcanic plateau origin of Paleoarchean continental lithosphere of the Pilbara and Kaapvaal cratons: Geological Society, London, Special Publications, v. 389, p. 89–111, doi:10.1144/SP389.12. | Van Kranendonk, MJ, Smithies, RH, Hickman, AH and Champion, DC 2007, Secular tectonic evolution of Archaean continental crust: Interplay between horizontal and vertical processes: Terra Nova, v. 19, p. 1–38. | Van Kranendonk, MJ, Smithies, RH, Hickman, AH, Wingate, MTD and Bodorkos, S 2010, Evidence for Mesoarchean (~3.2 Ga) rifting of the Pilbara Craton: The missing link in an early Precambrian Wilson cycle: Precambrian Research, v. 177, no. 1–2, p. 145–161, doi:10.1016/j.precamres.2009.11.007. | Vearncombe, S, Barley, ME, Groves, DI, McNaughton, NJ, Mikucki, EJ and Vearncombe, JR 1995, 3.26 Ga black smoker-type mineralization in the Strelley Belt, Pilbara Craton, Western Australia: Journal of the Geological Society, London, v. 152, p. 587–590. | Vearncombe, S, Vearncombe, JR and Barley, ME 1998, Fault and stratigraphic controls on volcanogenic massive sulphide deposits in the Strelley belt, Pilbara Craton, Western Australia: Precambrian Research, v. 88, no. 1–4, p. 67–82. | Witt, WK, Hickman, AH, Townsend, DB and Preston, WA 1998, Mineral potential of the Archaean Pilbara and Yilgarn Cratons, Western Australia: Journal of Australian Geology and Geophysics, v. 17, p. 201–221. |
| | | | Recommended reference for this publication | Hickman, AH 2024, East Pilbara Terrane Rifting Event (PCR): Geological Survey of Western Australia, WA Geology Online, Explanatory Notes extract, viewed 05 August 2025. <www.dmp.wa.gov.au/ens> |
| | | This page was last modified on 05 March 2024. | | | | | Grid references in this publication refer to the Geocentric Datum of Australia 1994 (GDA94). Locations mentioned in the text are referenced using Map Grid Australia (MGA) coordinates, Zones 49 to 52. All locations are quoted to at least the nearest 100 m. Capitalized names in text refer to standard 1:100 000 map sheets, unless otherwise indicated. WAROX is GSWA’s field observation and sample database. WAROX site IDs have the format ‘ABCXXXnnnnnnSS’, where ABC = geologist username, XXX = project or map code, nnnnnn = 6 digit site number, and SS = optional alphabetic suffix (maximum 2 characters). All isotopic dates are based on U–Pb analysis of zircon and quoted with 95% uncertainties, unless stated otherwise. U–Pb measurements of GSWA samples were conducted using a sensitive high-resolution ion microprobe (SHRIMP) in the John de Laeter Centre at Curtin University, Perth, Western Australia. Digital data related to WA Geology Online, including geochronology and digital geology, are available online at the Department’s Data and Software Centre and may be viewed in map context at GeoVIEW.WA. | | | Further details of geological publications and maps produced by the Geological Survey of Western Australia are available from: Information Centre Department of Mines, Industry Regulation and Safety 100 Plain Street EAST PERTH, WA 6004 Telephone: +61 8 9222 3459 Facsimile: +61 8 9222 3444 |
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