From: Geoscience Australia Report 2015
Ben Goscombe1, Richard Blewett2, Peter Skirrow2, Geoff Fraser2, Chris Carson2, Karol Carzanota2, Ben Wade3, John Everard4, Terry Brennan2, Others at Geoscience Australia2
1Integrated Terrane Analysis Research (ITAR).
2Geoscience Australia, P.O. Box 378, Canberra, 2601, ACT, Australia.
3Adelaide Microscopy, Adelaide University, Adelaide, 5005, SA, Australia.
4Mineral Resources Tasmania, P.O. Box 56, Rosny Park, 7018, Tasmania, Australia.
Metamorphic rocks preserve a record of transient first-order variables that are otherwise not available. Datasets, such as temperature, crustal depth, thermal regime and rates of cooling/heating and exhumation/burial are generated by back engineering metamorphic rocks. These datasets are fundamental geological variables that crucially constrain first-order patterns and gradients, crustal evolution, crustal processes, tectonic setting and at second-order scales are inter-related with deformation. Metamorphic rocks are crucial for three reasons:
[1] Metamorphic rocks preserve a long, near continuous, and relatively detailed record of crustal response to orogenic events and tectonic settings. Thus presenting an opportunity to back engineer orogenic episodes in the assembly and dispersal history.
[2] Metamorphic rocks are the only source of information on crustal depths and the individual particle paths tracked through the crustal column, and thus the most robust way of recognising lithospheric thinning and thickening events.
[3] Metamorphic rocks are the only source of information that tracks the long thermal evolution of the crust. The study of metamorphic rocks results in quantitative datasets of fundamental geological variables such as temperature (T), crustal depth or pressure (P), thermal regime (T/depth), P-T evolution paths and age of crystallization events (t). The spatial distribution patterns of these variables are also crucial datasets. Furthermore, the temporal integration of these datasets constrains the P-T evolutions tracked by different parts of the crust at different times and can constrain rates of crustal processes. The spatial and temporal patterns extracted from metamorphic rocks constrain the evolution of orogenic systems in robust fundamental ways that contribute insights into tectonic settings and history of the crust.
The rationale behind this research has been an integrated approach to generating metamorphic datasets and also their interpretation by spatial and temporal integration with deformation history, stratigraphy and magmatic history. Geological datasets are typically only integrated for a specific event at specific sites for a particular study. The approach taken has been to integrate data over the full history and scale of all Australian orogenic systems, using: time-space diagrams, evolution curves, annotated metamorphic maps and metamorphic field gradients. The integration of structural, metamorphic, magmatic, stratigraphy and chronology datasets has been shown to be crucial in documenting dynamic crustal architectures in many orogens globally (e.g. Goscombe et al., 2005a, 2006, 2014a,b, 2015a,b; Goscombe and Gray, 2007).
The aims of this research program are:
[1] To test for secular change in the thermal structure with time of the crust of different orogens, provinces and terranes making up the Australian continent.
[2] To collate all available metamorphic data for Australian metamorphic terranes, re-analyse this data and synthesis this re-analysis with pre-existing interpretations and models and find the common most robustly support integrated metamorphic history for each terrane.
[3] To take this synthesis further and interpret the most plausible tectonic setting and crustal architecture for each documented thermal and metamorphic event / orogeny.
[4] From this spatially reference metamorphic history of each metamorphic terrane; to ultimately distil this body of knowledge into a fully comprehensive listing of all the events and orogeny's that left a thermal or barometric imprint on the Australian continent, and the distribution, extent and timing of each of these thermo-metamorphic events.
[5] An outcome of the process of this research is new interpretive metamorphic map and data layers covering the whole continent.
The background to this research program has been ongoing in fits and start from 1986 with collation of metamorphic data and submission of unsuccessful proposals to produce statewide metamorphic maps for Tasmania, Western Australia and Northern territory. Ongoing ITAR research has been progressively adding to a metamorphic database for different parts of Australia.
The traditional metamorphic map suffers from being based on metamorphic facies, which document temperature variation and typically contain little pressure information. Without pressure information encoded, traditional metamorphic map patterns can lead to deceptive interpretations. For example, the progressive increase in metamorphic facies grade (i.e., T) towards granite/gneiss domes in the East Yilgarn Craton gave a superficial impression of simple contact metamorphism. However, the highest-grade rocks at some dome margins also experienced disproportionally higher pressures and were counter-intuitively formed in much cooler thermal regimes (i.e., low T/depth). Consequently, the high-grade margins are incompatible with both contact metamorphism, nor could they have formed at the same time as the lower grade, but higher thermal regime metamorphic rocks distant from the domes. Another common example is that, without pressure data encoded in the metamorphic map of collisional orogens, such as the Himalayan and Damara orogens, their true paired-metamorphic architecture would not be apparent. The traditional temperature only facies-series metamorphic map would otherwise merely show a systematic increase in temperature across the orogen. Most orogenic systems contain fundamental metamorphic discontinuities between regions of different T/depth ratios indicating different thermal regimes or subsequent extensional telescoping or over-thrusting. Many metamorphic terranes, whether convergent, transpressional or extensional, are marked by strong variation in thermal regime (i.e. P-series or T/depth ratio) and are indeed complex paired metamorphic systems. Identification of the true metamorphic architecture that accounts for P-variation and thermal regime (T/depth), is crucial to constraining palaeo-tectonic settings in old, deeply eroded metamorphic terrane without boundary conditions or context to constrain the tectonic setting at the time of formation. This desired level of tectonic utility in metamorphic maps, has been achieved by mapping metamorphic fields based on breaking up P-T space on the basis of both metamorphic facies (T) and pressure-series (T/depth), as discussed in detail below.
Distinct ranges of plausible T/depth regime in different tectonic settings illustrate the tectonic significance of accounting for pressure-series. To calibrate the tectonic interpretative use of T/depth regime, this data was collated from the global literature for metamorphic terranes where the tectonic settings is well documented, and summarized here.
[1] Hornfels or very low pressure-series with T/depth ratios of >120 ºC (VLP) are characteristic of shallow contact aureole environments, hydrothermal settings and ocean crust metamorphism.
[2] High-T/low-P or low pressure-series with T/depth ratios of 50-120 ºC (LP) are characteristic of extreme dominance of heat conduction over advection, such as in contact aureoles, or high heat flow environments involving magma accretion coupled with thermal blanketing, such as magmatic arcs.
[3] Buchan or medium pressure-series with T/depth ratios of 25-50 ºC (MP) are characteristic of slow material advection rates and/or high heat flow due to either; mantle lithosphere thinning, magmatic accretion, high radiogenic heat generation or efficient thermal blanketing by thick sedimentary sequences.
[4] Barrovian or high pressure-series with T/depth ratios of 15-25 ºC (HP) are characteristic of continental collisional orogens experiencing relatively fast material advection rates in quasi-equilibrium with conduction and internal radiogenic generation of heat.
[5] Blueschist-eclogite or very high pressure-series with T/depth ratios of <15 ºC (VHP) are characteristic of settings where fast advection of material out competes conduction of heat, such as within subduction regimes.
The generation of meaningful metamorphic maps has historically also been hampered by different aged metamorphic parageneses being presented together as a single composite metamorphic map pattern. Rarely does a metamorphic terrane record only one metamorphic event/orogeny. Unlike stress field switching, transitions between different metamorphic periods involve slow rates, conductive delays and a less punctuated history than the structural evolution. Different aged metamorphic parageneses can be recognised by either over-printing criteria, geochronology of metamorphic minerals, or stratigraphic and magmatic age controls. These different aged peak metamorphic parageneses may have formed in separate orogenic cycles or are recognisably different events within the one orogenic cycle. As discussed above, composite metamorphic maps need to incorporate more than just one geological variable (T) to be generally useful for tectonic interpretation. This argument can be extended further to show the need for more than the two variables, T and P, because metamorphic parageneses of different age may have formed at markedly different: (1) conditions, (2) tectonic settings, (3) metamorphic style (contact, static, dynamic, reworking, reactivation, regional etc.) and (4) spatial distributions (partitioned in shear zones/aureoles to regionally extensive). Different aged parageneses can form at either: (1) the same locality due to a complex reworking history such as in Proterozoic provinces, or alternatively, (2) there may be variation in age of peak metamorphic parageneses across the orogeny/province, such as in the accretionary Lachlan Orogen.
It is impossible to construct a metamorphic map that has more than two variables presented in 2D space in the one data layer. Consequently, the best that can be achieved incorporates the two variables T and P (T/depth or P-series) in a composite metamorphic map layer that represents the "time-independent spatial distribution of peak metamorphic conditions attained at that locality" - or simply the composite metamorphic map. To account for variation in the age of different metamorphic parageneses, both at the same locality and spatially, the composite metamorphic map layer has age data added to it in three ways: by annotation, over-hatching and time-slice maps.
The basis for any metamorphic map is how P-T space is sub-divided into metamorphic fields. Because of the arguments above, the scheme adopted for this project is to define metamorphic fields by both metamorphic facies (T) and pressure-series (T/depth). Each pressure-series band (see above) has a fundamentally different colour series. Metamorphic facies (or temperature-series) gradient within the different pressure-series bands is represented by increasing colour intensity towards higher temperatures. For example pale yellows through oranges to reds. In this way fundamentally different colours on the metamorphic map indicate changes in P-series and thus probable metamorphic discontinuities or thermal regimes, with consequent tectonic significance.
The metamorphic fields are defined in reality - in rocks - by diagnostic mineral fields (DMF) or assemblages/parageneses formed at characteristic P-T conditions. These diagnostic assemblages are of coarse highly dependent on the bulk composition of the rock. Consequently, just two of the most common, widely distributed, well studied and with narrow bulk compositional variation, have been used to define these diagnostic mineral fields. These are:
[1] A composite petrogenetic grid has been constructed across P-T space (0-24 kb and 0-1200 ºC), from published pseudosections for average metapelite compositions in MnNCKFMASH space. Diagnostic mineral fields are best-fit P-T fields defined by key mineral assemblages and are not true pseudosection fields. Consequently, these composite petrogenetic grids are used as legends for the metamorphic maps and are not intended to replace P-T pseudosections for the interpretation of individual rock samples.
[2] A composite petrogenetic grid has also been constructed across P-T space (0-24 kb and 0-1200 ºC), from published pseudosections for average tholeiite compositions in NCFMASH space.
The definition and details of the diagnostic mineral fields in both systems has been tabulated in and synthesised into a general legend for the metamorphic maps generated by this project. These two composite petrogenetic grids have self-similar DMF's that overlap each other remarkably well with near similar P-T ranges. Consequently, a unique scheme for labelling the diagnostic metamorphic fields can be applied to both grids. To analyse this concordance between the two composite grids further, the boundaries of the facies and sub-facies defined by the two composite petrogenetic grids have been over-layered to find overlap in common. By doing this two things are achieved: (1) the median line between the two alternative definitions of facies and sub-facies can be constructed, and this can be considered the best-fit definition for the boundary between facies and sub-facies. (2) The regions that do not over-lap perfectly are highlighted and thus act as the error band on the synthesized best-fit facies and sub-facies boundaries.
An inset that expands the details of the low-PT part of P-T space has been constructed as a composite petrogenetic grid to define the diagnostic mineral fields and sub-facies at low-PT. This grid has been constructed by synthesis of experimental, theoretical and empirical phase stability data for a large range of low-temperature minerals. This mineral stability data is almost entirely from calcareous to tholeiitic bulk compositions applicable to mafic rocks.
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Depending on how you slice it, at least 48 distinct orogenic cycles - with metamorphic response - have been recognised in parts of the Australian continent (ignoring minor or restricted events such as shear zone reactivation and intrusions, as well as undifferentiated or poorly constrained events); a history spanning from the Palaeoarchaean to now:
[1] Rifting, breakup and drift events at Australian continental margins 0-180 Ma.
[2] Contraction in the Hunter-Bowen and Fitzroy Basins 210-255 Ma.
[3] New England Orogenic Cycle 300-485 Ma.
[4] Lachlan-Thompson Orogenic Cycle 320-465 Ma.
[5] Alice Springs Orogeny 320-450 Ma.
[6] Larapinta Rift Event 450-490 Ma.
[7] Delamerian-Tyennan Orogenic Cycle with late Kanmantoo Rift Event 500-540 Ma.
[8] Petermann Orogeny reworking of Paterson and Musgrave Provinces 520-560 Ma.
[9] Pinjarra Orogenic Cycle from subduction to collisional phases 500-680 Ma.
[10] Wickham Orogeny ~760 Ma.
[11] Edmundian Orogeny in Gascoyne Province 950-1030 Ma.
[12] M3 Metamorphic Event in Albany-Fraser Orogen, Ngaanyatjarra Event in Musgrave Province, Pre-Pinjarra Event and the Warakuma-Giles Mafic Event are all probable extension related thermal events in the range 1025-1120 Ma.
[13] M2 Metamorphic Event in Albany-Fraser Orogen, Musgravian Orogeny in Musgrave Province and the Marnda Moom Mafic Event are probable related events in the range 1130-1212 Ma.
[14] Rudall Metamorphism 1220-1310 Ma.
[15] King Island Orogeny 1240-1290 Ma.
[16] M1 Metamorphic Event in Albany-Fraser Orogen, Mount West Orogeny in Musgrave Province and the Fraser Mafic Event are probable related events in the range 1280-1350 Ma.
[17] Late Isan Orogeny in Mount Isa Province, Mundi Mundi Magmatic Event in Curnamona Province and Wartaken Event in Gawler Craton are probable related events in the range 1500-1530 Ma.
[18] Middle Isan or Williams Magmatic Event in Mount Isa Inlier, Jana Orogeny in Georgetown Inlier, "Benagerie" Magmatic Event in Curnamona Province and Kararan Orogeny in Gawler Craton are probable related events in the range 1543-1565 Ma.
[19] Early Isan Orogeny senso stricto in Mount Isa Inlier, Ewamin Orogeny in Georgetown Inlier, Nawa II Orogeny in northern Gawler Craton, Chewings Orogeny in Arunta Province and Curramulka Mafic Event are probable related events in the range 1570-1600 Ma.
[20] Olarian Orogeny in Curnamona Province, earlier phases of the Nawa II Orogeny in northern Gawler Craton, Gawler Range and Hiltiba Suite in the Gawler Craton and Ormiston Orogeny in Arunta Province are probable related events in the range 1590-1610 Ma.
[21] Nawa I Orogeny in northern Gawler Craton, "St Peter" Magmatic Event in Gawler Craton, Poodla Hill Magmatic Event in Curnamona Province, Tommy Creek Event in Mount Isa Province, Liebig Orogeny in Warumpi and Arunta Provinces and Andrew Young Mafic Event are probable related events in the range 1620-1650 Ma.
[?] The Sybella Magmatic Event in Mount Isa Province, Tunkillia Magmatic Event in Gawler Craton, Argilke Magmatic Event in Warumpi Province and Woman-In-White and Lady Louise-Parnell Mafic Event are very tenuously related events in the range 1655-1690 Ma.
[22] Mangaroon Orogeny in the Gascoyne Province 1620-1680 Ma.
[23] Biranup Event in the Albany-Fraser Orogen 1660-1690 Ma.
[24] Kimban Orogeny in the Gawler Craton, Strangways Orogeny in the Arunta Province, Basso Magmatic Event in Curnamona Province and Oenpelli Mafic Event are probable related events in the range 1700-1730 Ma.
[25] The Wonga Extensional Magmatic Event in Mount Isa Province and Inkamulla Igneous Event in Arunta Province are probable related events in the range 1740-1760 Ma.
[26] The Leichhardt-Myally Rift Event in Mount Isa Province, Yamba Orogeny in Arunta Province, Shoobridge Orogeny in Pine Creek Orogen and Attutra Mafic Event are probable related events in the range 1770-1790 Ma.
[27] Capricorn Orogeny in the Gascoyne Province 1780-1856 Ma.
[28] The Stafford Orogeny in Arunta Province, Welltree Metamorphism in Litchfield Province and Mount Hay Mafic Event are probable related events in the range 1800-1813 Ma.
[29] The Tanami Orogeny in Tanami Province, Halls Creek Orogeny in Halls Creek Orogen and Edmirringee and Mumbillia Mafic Events are probable related events in the range 1825-1845 Ma. The Neill Creek Magmatic and Metamorphic Event of ~1850 Ma in the Gawler Craton is of similar age, though probably unrelated.
[30] The Fog Bay-Hermit Creek Metamorphism in the Litchfield Province, Hooper-Nimbuwah Orogeny in the Pine Creek Orogen, "Kalkadoon" Event in the Mount Isa Province and Wangi Mafic Event are probable related events in the range 1850-1870 Ma.
[31] The Barramundi Orogeny in the Mount Isa Province and Bow River Mafic Event are probable related events in the range ~1875-1900 Ma.
[32] Glenburgh Orogeny in the Gascoyne Province 1960-2005 Ma.
[?] Miltalie Magmatic Event of unknown nature and extent in the Gawler Craton ~2000 Ma.
[33] Ophthalmian Orogeny in the Capricorn Orogen 2145-2215 Ma.
[34] Sleafordian Orogeny in Gawler Craton 2437-2447 Ma.
[35] Dutton Event and Blackfellow Hill Mafic Event in Gawler Craton ~2450-2550 Ma.
[36] Undifferentiated metamorphic and magmatic events in basement to Pine Creek Orogen ~2470-2675 Ma.
[37] Undifferentiated isotopic disturbance event in Yilgarn Craton ~2540-2615 Ma.
[38] Delamination related M3b metamorphism in the Yilgarn Craton: mineralization events in Kalgoorlie-Kurnalpi Terranes and peak metamorphic events in Southwest, Narryer and Youanmi Terranes 2620-2655 Ma.
[39] Extension related M3a metamorphism in the Yilgarn Craton: rift metamorphism in Kalgoorlie-Kurnalpi Terranes and probable extensional metamorphic events in Southwest, Narryer and Youanmi Terranes 2650-2665 Ma.
[40] Granite bloom related M2 regional-contact metamorphism in all parts of the Yilgarn Craton 2655-2685 Ma.
[41a] Magmatic arc (Ma) and arc accretion (M1) parageneses related to amalgamation of the Kalgoorlie and Kurnalpi Terranes and associated mafic intrusives 2695-2715 Ma. A poorly constrained metamorphic event in the Narryer Terrane of 2700-2715 Ma age is tentatively correlated.
[41b] Magmatic arc (Ma), arc accretion (M1) and regional metamorphic parageneses related to amalgamation of the Burtville and Kurnalpi Terranes and associated mafic intrusives 2727-2755 Ma.
[42] Probable early regional metamorphism in the Narryer and Youanmi Terranes 2772-2775 Ma.
[43] Early extension related mafic igneous complexes and contact metamorphism in the Youanmi Terrane 2792-2825 Ma.
[44] Poorly constrained metamorphic event in the Pilbara Craton 2875-2890 Ma.
[45] Probable early metamorphism in the Narryer and Southwest Terranes 3180-3195 Ma. This coincides in age with 3200 Ma seafloor metamorphism in young sequences in the Pilbara Craton, though is probably unrelated.
[46] Probable early metamorphism in the Narryer Terrane 3291 Ma. This overlaps in age with regional metamorphism in the Pilbara Craton, though is probably unrelated.
[47] Poorly constrained regional metamorphic events in the Pilbara Craton span ~3238-3410 Ma.
[48] Early seafloor metamorphism and early mafic intrusives and contact metamorphism in the Pilbara Craton 3459-3490 Ma.
Superimposed within this big picture framework are numerous metamorphic events within orogenic cycles and spatially restricted thermal overprints associated with magmatism, extension, rifting and dispersal during and between these major orogenic cycles. The identified metamorphic events and cycles are based on: over-printing relations, absolute timing of metamorphic parageneses, absolute PT conditions, contrasting P-T paths and thermal regimes; and distinct structural settings, chrono-stratigraphic rock units and tectono-metamorphic terranes. Interpretations of the absolute timing of these metamorphic periods have been made by correlations with extrusive, intrusive, basinal and deformation histories and direct dating of metamorphic minerals.
In addition to this extended history of recognisable orogenic thermal events, are localized thermal anomalies associated with extension-related mafic intrusive events recorded in the Australian crust. Some of these produced, or at least potentially produced, new contact metamorphic parageneses that are useful in constraining the barometric conditions at the time of intrusion. The record of these mafic intrusive events is also crucial because most are very accurately dated and so act as time markers that collectively act as a barcode of extensional events. This both helps pin down and constrain the orogenic history of Australia but also are a record of extension, for which there may otherwise be very little expression if upper crust rift sediment sequences have been eroded from the geological record. Further, these documented expressions of extensional may also be indicating the plausibility of broader thermal anomalies due to lithospheric extension, that is otherwise not immediately apparent but may be important in understanding: disturbed isotopic systems, petroleum and coal maturation histories and even development and re-equilibration of metamorphic parageneses more widely. A summary of the identified mafic LIP events to effect Australia (Hoatson et al., 2006, 2007) are listed here:
[1] Mt Gambier Volcanic Event [0-1.5 Ma]
[2] Breakup Event [84-180 Ma]
[3] Larapinta Mafic Event [450-490 Ma]
[4] Kalkaringa Mafic Event [510-530 Ma]
[5] Passive Margin Mafic Event [580-600 Ma]
[6] Mundine Well Mafic Event [750-755 Ma]
[7] Boucaut Mafic Event [775 Ma]
[8] Gairdner Mafic Event [825 Ma]
[9] Giles-Warakurna Mafic Event [1070-1075 Ma]
[10] Mordor Mafic Event [1130 Ma]
[11] Marnda Moom Mafic Event [1210-1212 Ma]
[12] Fraser Mafic Event [1301 Ma]
[13] Derim Derim Mafic Event [1320 Ma]
[14] Bangemall Mafic Event [1465 Ma]
[15] Curramulka Mafic Event [1590 Ma]
[16] Andrew Young Mafic Event [1630-1640 Ma]
[17] Tarcoola Mafic Event [1655 Ma]
[18] Woman-In-White Mafic Event [1685 Ma]
[19] Wonga Mafic Event [1694-1800 Ma]
[20] Oenpelli Mafic Event [1725 Ma]
[21] McGregor Mafic Event [1740 Ma]
[22] Attutra-Harts Mafic Events [1770-1790 Ma]
[23] Tournefort Mafic Event [1812 Ma]
[24] Mount Hay Mafic Event [1800-1820 Ma]
[25] Sally May-Edirringee-Mumbilla-Wangi Mafic Events [1820-1860 Ma]
[26] Bow River Mafic Event [1860-1880 Ma]
[27] Stag Creek-Paraburdoo Mafic Events [2010, 2020 Ma]
[28] Turee Creek Mafic Event [2210 Ma]
[29] Widgiemooltha Mafic Event [2410-2420 Ma]
[30] Weeli Wolii-Blackfellow Hill Mafic Events [2450-2460 Ma]
Finally, as if all this were not enough, being an old stable continental mass, Australia preserves a relatively long record of very short-lived extreme barometric anomalies associated with asteroid impacts. Impact craters with documented or probable shock metamorphism features are listed here:
[1] Probable Hickman Impact [0.000105 Ma]
[2] Henbury Impact [0.0042±0.0019 Ma]
[3] Boxhole Impact [0.0054±0.0015 Ma]
[4] Dalgaranga Impact [~0.27 Ma]
[5] Wolfe Creek Impact [<0.3 Ma]
[6] Probable Edeowie Impact [0.725±0.055]
[7] Probable Darwin Impact [0.816±0.007 Ma]
[8] Veevers Impact [<1 Ma]
[9] Probable Haines Impact [<23-56 Ma]
[10] Probable North Bonaparte Impact [30.3±5.7 Ma]
[11] Crawford Impact [>35 Ma]
[12] Flaxman Impact [>35 Ma]
[13] Goat Paddock Impact [<50 Ma]
[14] Connolly Impact [<60 Ma]
[15] Probable Yallalie Impact [<65-250 Ma]
[16] Mount Toondina Impact [<110 Ma]
[17] Probable Talundilly Impact [125±1 Ma]
[18] Tookoonooka Impact [128±5 Ma]
[19] Gosses Bluff Impact [142.5±0.8 Ma]
[20] Liverpool Impact [150±70 Ma]
[21] Probable Bedout Impact [250.1±4.5 Ma]
[22] Piccaninny Impact [<360 Ma]
[23] Probable East Warburton Impact [360 Ma]
[24] Woodleigh Impact [364±8 Ma]
[25] Glikson Impact [<508 Ma]
[26] Lawn Hill Impact [>515 Ma]
[27] Foelsche Impact [>545 Ma]
[28] Kelly West Impact [>550 Ma]
[29] Spider Impact [>570 Ma]
[30] Acraman Impact [~590 Ma]
[31] Amelia Creek Impact [600-1640 Ma]
[32] Strangways Impact [646±42 Ma]
[33] Goyder Impact [<1400 Ma]
[34] Matt Wilson Impact [1402±440 Ma]
[35] Shoemaker-Teague Impact [1630±5 Ma]
[36] Yarrabubba Impact [~2000 Ma]
[37] Unnamed Pilbara Impact [2630 Ma]
[38] Probable Mount Toondina Impact [unknown age]
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Links:
[1] http://www.terraneanalysis.com.au/projects/australia#OZMPtop