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The present-day mantle is divided into the African and Pacific domains by the circum-Pacific subduction girdle. Very little is known about the mantle composition of the Pacific Domain before 120 Ma due to the scarcity of the oceanic record, having mostly been destroyed by subduction processes. Accreted oceanic lithosphere (ophiolites) in orogens along the Paleo-Pacific margins provide rare opportunities to partially fill this knowledge gap. The early Cambrian (530–505 Ma) Weraerai ophiolite mélange in the New England Orogen in Eastern Australia represents fragments of the now-consumed Paleo-Pacific oceanic plate, predecessor of the Panthalassa and Pacific oceanic plates, accreted to east Gondwana during c. 410–277 Ma. Early work revealed the presence of an accreted volcanic island(s) of possible mantle plume origin. However, due to their heavy alteration and weathering, the geochemical signature of the mafic rocks in the Weraerai ophiolite cannot be used to certify their plume origin with confidence. Therefore, mantle rocks found in the ophiolitic belt offer an alternative way to decipher the origin of the oceanic lithospheric fragments in the Weraerai ophiolite mélange. Here, we report the petrographic, major and trace elements composition, including highly siderophile elements (HSE), and Re–Os isotope composition for 16 serpentinized spinel harzburgite samples from Woodsreef and Port Macquarie. The observed spinel–orthopyroxene symplectite intergrowth textures are interpreted as garnet-breakdown textures due to cooling from an initial high temperature of >1200°C. Silicon and Al contents and Mg# of serpentinized spinel harzburgite, as well as heavy rare earth element modeling results, suggest a high-degree of melt extraction of 20–30% in the garnet stability field and in an anhydrous environment, probably in ocean island or oceanic plateau environments. The samples in this study have HSE concentrations interpreted to have resulted from post-melting processes rather than a melt extraction feature, indicating that their Re–Os model ages need to be interpreted with caution. Nevertheless, the melt depletion ages obtained from the Woodsreef and Port Macquaries samples range between 1.4 and 1.1 Ga, consistent with previous studies on other Pacific-rim ophiolitic rocks. We argue that these ages might be related to a major depletion event during the transition between supercontinents Nuna and Rodinia. Such depletion events affected a large proportion of this section of the mantle before the incorporation of the peridotites into the oceanic lithosphere in the Paleo-Pacific associated with rapid ascent of mantle plumes. This interpretation is consistent with the occurrence of accreted volcanic islands in the Weraerai ophiolite mélange, as shown by the OIB chemical signatures of some of the mafic rocks, and their association with shallow water limestones that formed in near-equatorial latitudes. The proposed c. 530–510 Ma Paleo-Pacific Ocean mantle plume event coincides with a global peak of oceanic mantle plume events that may record the legacy of a circum-Rodinia subduction girdle driving antipodal mantle superplume episodes. [ABSTRACT FROM AUTHOR]

In this paper, we propose an iterative approach within a threshold quantile regression framework to identify sequential structural breaks. We apply it to a time series analysis with a focus on establishing a connection between structural breaks in the gasoline consumption function and extreme events in the economy. The estimated structural breaks and piecewise relationship between Australia's automobile gasoline consumption and household disposable income are consistent with economic intuition. Moreover, the heterogeneity in their relation across various quantiles and over different time periods divided by the identified structural breaks is revealed in a systematic manner. The comparison with a state-of-practice approach demonstrates the validity and efficiency of our approach. [ABSTRACT FROM AUTHOR]

We use a variant of machine learning (ML) to forecast Australia's automobile gasoline demand within an autoregressive and structural model. By comparing the outputs of various model specifications, we find that training set selection plays an important role in forecasting accuracy. More specifically, however, the performance of training sets starting within identified systematic patterns is relatively worse, and the impact on forecast errors is substantial. We explain these systematic variations in machine learning performance, and explore the intuition behind the 'black-box' with the support of economic theory. An important finding is that these time points coincide with structural changes in Australia's economy. By examining the out-of-sample forecasts, the model's external validity can be demonstrated under normal situations; however, its forecasting performance is somewhat unsatisfactory under event-driven uncertainty, which calls on future research to develop alternative models to depict the characteristics of rare and extreme events in an ex-ante manner. • It examines the role of training set selection in demand forecasting. • It relates systematic variations in forecasts to structural changes in the economy. • It explores the economic intuition behind the 'black-box'. [ABSTRACT FROM AUTHOR]

Abstract: Geochemical and Hf–Nd isotope studies of Neoproterozoic sedimentary and volcaniclastic rocks in the Nanhua Rift Basin, South China, demonstrate that their source provenances contained large proportions of mafic rocks and various amounts of granites. A significant proportion of the studied Neoproterozoic rift sedimentary and volcaniclastic rocks have initial εNd(t) values higher than those of Neoproterozoic granites, but fall within the range of ca. 825–750Ma basaltic rocks. Their initial εNd(t) values correlate with ratios of La/Sc, La/Cr, La/V, La/Co and La/Ni. The Nd isotope and trace element data, in combination with existing in-situ U–Pb and hafnium–oxygen isotope data from the detrital zircon grains indicate a dominant ca. 825–800Ma mafic provenance. Furthermore, the studied samples formed a linear array and plot within the field defined by the remanent of ca. 825–810Ma continental flood basalts in the Hf–Nd isotopic space. Thus, the inferred large proportions of mafic rocks in the source provenance of the Neoproterozoic rift sedimentary and volcaniclastic rocks likely signify an eroded continental flood basalt province, similar to that reported for the Neoproterozoic sedimentary rocks in Australia. This work thus provides further evidence for the possible once existence of a common large igneous province between South China and eastern Australia as adjacent parts of the supercontinent Rodinia. [Copyright &y& Elsevier]

Abstract: This paper reviews public transport crowding valuation research, using a number of primary studies conducted in the UK, USA, Australia and Israel. We identify three measures used to value crowding (a time multiplier, a monetary value per time unit and a monetary value per trip), and associated ways of representing crowding in stated preference experiments. Although a number of different types of crowding in terms of location are identified, namely in-vehicle, access-way, entrance and platform/station, the majority of reviewed studies investigate only in-vehicle crowding. Despite the different characteristics of the reviewed studies, they all report that crowding would increase the value of travel time savings, which can be viewed as an additional component of generalised time. This paper also comments on the role that the WTP for crowding reduction can play in project appraisal, and suggests some important avenues for future public transport crowding valuation research. [Copyright &y& Elsevier]

Abstract: One key initiative to reducing the environmental impact of motor vehicles is to identify the number and types of vehicle in the vehicle stock which are likely to excessively contribute to air pollution. Such an assessment is dependent on quantifying vehicle scrappage which, in turn, relies on the provision of temporally consistent motor vehicle registration data. There exist a number of issues that adversely impact on the temporal accuracy of motor vehicle registration data. This paper identifies these issues and proposes a cost effective correction framework for motor vehicle registration time series data. An application to Australian data is used to demonstrate the efficacy of the framework, identifying the need to introduce an additional vehicle category into the data, adjusting annual vehicle counts and removing the erroneous incidence of the number of vehicles in a vintage class that increase substantially beyond 2years after the year of manufacture. [Copyright &y& Elsevier]

A primary motivation of this paper is to draw together, in one source, information on the nature, extent and performance of Australia's evolving toll road network which is currently spread across many disparate published and unpublished sources. This paper provides key information (e.g. length, toll rates, year opened, operator(s) and payment alternatives) on all of the fully interoperable toll roads in Australia that are present in Sydney (e.g. the M2, M4, M5, etc.), Melbourne (CityLink and EastLink) and Brisbane (the Gateway Bridge, the Logan Motorway and the Gateway Extension). Where available, we compare and discuss actual traffic levels and forecasts, revealing the sizeable gap or 'error' in forecasts, especially during the first year of operation. Ordinary least squares regression and panel random effects regression models are developed to identify potential sources of explanation of differences in error forecasts between the Australian toll roads at various points post the opening date. A separate analysis of a sample of toll roads in the USA was also undertaken that supports the main findings from the Australian toll road network. Key influences on errors in forecasts are the capacity of a toll road, the elapsed time that the toll road has been in place, the specific period of time in which a tolled road is introduced into the network (which influences the complexity of route options including multiple tolled routes and hence toll saturation), the length of the tolled route, the presence of cash payment and the charging regime (i.e. fixed vs. distance-based or variable user tolls). [ABSTRACT FROM AUTHOR]

Abstract: Transport fuel consumption and its determinants have received a great deal of attention since the early 1970s. In the literature, different types of modelling methods have been used to estimate petrol demand, each having methodological strengths and weaknesses. This paper is motivated by an ongoing need to review the effectiveness of empirical fuel demand forecasting models, with a focus on theoretical as well as practical considerations in the model-building processes of different model forms. We consider a linear trend model, a quadratic trend model, an exponential trend model, a single exponential smoothing model, Holt’s linear model, Holt–Winters’ model, a partial adjustment model (PAM), and an autoregressive integrated moving average (ARIMA) model. More importantly, the study identifies the difference between forecasts and actual observations of petrol demand in order to identify forecasting accuracy. Given the identified best-forecasting model, Australia’s automobile petrol demand from 2007 through to 2020 is presented under the “business-as-usual” scenario. [Copyright &y& Elsevier]

Precambrian palaeointensity measurements provide fundamental constraints on the evolution of the deep Earth. Core evolution models predict trends in dipole moment on billion-year timescales that can be tested by palaeomagnetic records. Here, we report new palaeointensity results from the recently identified ∼2.62 Ga Yandinilling dyke swarm of the Yilgarn Craton, Western Australia, and consider them alongside published measurements spanning 500 Myr across the late Archaean to earliest Proterozoic. Rock magnetic and scanning electron microscopy analysis confirm that the magnetic mineralogy is fine-grained magnetite, appearing mostly as exsolved lamellae with ilmenite. Six sites produced acceptable palaeointensity estimates from thermal and microwave IZZI protocol Thellier experiments and from double-heating technique Shaw experiments. These site mean values of 9–26 µT translate to virtual dipole moments of 11–44 ZAm2 that are considerably lower than today's dipole moment of ∼80 ZAm2 and the value predicted for this time period by some thermal evolution models. Their average (median = 41 ZAm2) is, however, similar to the long-term average during both of the intervals 2300–2800 Ma (median = 44 ZAm2; N  = 103) and 10–500 Ma (median 41 ZAm2; N  = 997). While there is little evidence for a substantial net change in average dipole moment between the late Archaean and Phanerozoic, there is preliminary evidence that its variance has increased between the two intervals. This lower variance more than two billion years ago supports the idea that the geodynamo, even while not producing a stronger magnetic field, was more stable on average at the Archaean–Proterozoic transition than it is today. [ABSTRACT FROM AUTHOR]

• Sedimentary rocks can record the assembly and breakup of supercontinents. • Ancient North America (Laurentia) assembled by 1.7 billion years ago. • 1.4 billion year old rocks in western N. America were sourced from Australia. • Australia was likely connected to western N. America after 1.7 billion years ago. • Australia likely broke away from western N. America 1.3 billion years ago. Rocks of the Gold Cup Quartzite, Belt Supergroup and Deer Trail Group crop out in the Priest River region of northeastern Washington and northern Idaho (USA). As these sequences represent the westernmost exposures of Paleoproterozoic–Mesoproterozoic strata between New Mexico (USA) and the northern Yukon (Canada), they are key to understanding the assembly of Laurentia and evaluating the duration and configuration of the supercontinent Nuna/Columbia. Here, we present detrital zircon U–Pb and Lu–Hf isotope data from these sequences. The results indicate that the <1.73 Ga Gold Cup Quartzite contains similar detrital zircon components to other widespread late Paleoproterozoic units that record final assembly of the main Archean blocks of western Laurentia; as such, they do not require any non-Laurentian source. Prominent ca. 1.7–1.5 Ga, isotopically juvenile zircon grains form the main component of the overlying ca. 1.47 Ga Lower Belt Supergroup. Some of these detrital zircon components lack a Laurentian source and are instead consistent with derivation from the Gawler Craton in southeastern Australia. The >1.38 Ga upper Belt Supergroup strata are structurally overlain by <1.3 Ga Deer Trail Group rocks that contain detrital zircon components consistent with mixed Laurentian sources. The paucity of any syndepositional volcanic detrital zircon in Deer Trail Group strata along with its fine siliciclastic and carbonate nature suggest deposition within a tectonically-quiescent basin coeval with breakup of Nuna. [ABSTRACT FROM AUTHOR]

The final assembly of the Mesoproterozoic supercontinent Nuna was marked by the collision of Laurentia and Australia at 1.60 Ga, which is recorded in the Georgetown Inlier of NE Australia. Here, we decipher the metamorphic evolution of this final Nuna collisional event using petrostructural analysis, major and trace element compositions of key minerals, thermodynamic modelling, and multi‐method geochronology. The Georgetown Inlier is characterised by deformed and metamorphosed 1.70–1.62 Ga sedimentary and mafic rocks, which were intruded by c. 1.56 Ga old S‐type granites. Garnet Lu–Hf and monazite U–Pb isotopic analyses distinguish two major metamorphic events (M1 at c. 1.60 Ga and M2 at c. 1.55 Ga), which allows at least two composite fabrics to be identified at the regional scale—c. 1.60 Ga S1 (consisting in fabrics S1a and S1b) and c. 1.55 Ga S2 (including fabrics S2a and S2b). Also, three tectono‐metamorphic domains are distinguished: (a) the western domain, with S1 defined by low‐P (LP) greenschist facies assemblages; (b) the central domain, where S1 fabric is preserved as medium‐P (MP) amphibolite facies relicts, and locally as inclusion trails in garnet wrapped by the regionally dominant low‐P amphibolite facies S2 fabric; and (c) the eastern domain dominated by upper amphibolite to granulite facies S2 foliation. In the central domain, 1.60 Ga MP–medium‐T (MT) metamorphism (M1) developed within the staurolite–garnet stability field, with conditions ranging from 530–550°C at 6–7 kbar (garnet cores) to 620–650°C at 8–9 kbar (garnet rims), and it is associated with S1 fabric. The onset of 1.55 Ga LP–high‐T (HT) metamorphism (M2) is marked by replacement of staurolite by andalusite (M2a/D2a), which was subsequently pseudomorphed by sillimanite (M2b/D2b) where granite and migmatite are abundant. P–T conditions ranged from 600 to 680°C and 4–6 kbar for the M2b sillimanite stage. 1.60 Ga garnet relicts within the S2 foliation highlight the progressive obliteration of the S1 fabric by regional S2 in the central zone during peak M2 metamorphism. In the eastern migmatitic complex, partial melting of paragneiss and amphibolite occurred syn‐ to post‐ S2, at 730–770°C and 6–8 kbar, and at 750–790°C and 6 kbar, respectively. The pressure–temperature–deformation–time paths reconstructed for the Georgetown Inlier suggest a c. 1.60 Ga M1/D1 event recorded under greenschist facies conditions in the western domain and under medium‐P and medium‐T conditions in the central domain. This event was followed by the regional 1.56–1.54 Ga low‐P and high‐T phase (M2/D2), extensively recorded in the central and eastern domains. Decompression between these two metamorphic events is ascribed to an episode of exhumation. The two‐stage evolution supports the previous hypothesis that the Georgetown Inlier preserves continental collisional and subsequent thermal perturbation associated with granite emplacement. [ABSTRACT FROM AUTHOR]

The geodynamic regimes that operated during the Mesoproterozoic amalgamation of the first supercontinent on Earth, Nuna, remain poorly understood. Palaeogeographic Nuna reconstructions indicate that NE Australia and NW Laurentia were adjacent at its core—the ca. 1600 Ma collision between the Australian upper-plate (i.e., the Mount Isa Inlier) and the western Laurentian lower-plate (i.e., the Georgetown Inlier) was followed by a post-collisional, extensional regime associated with widespread low-pressure (LP) and high-temperature (HT) metamorphism and the formation of voluminous granitic melts. To better understand the tectonic regimes and crustal processes that operated during this Proterozoic orogenic system, new coupled U Pb and Lu Hf analyses from Mesoproterozoic granites in NE Australia are used to examine the ca. 1560 to 1540 Ma magmatism that occurred during the waning stages of Nuna amalgamation. LT , hydrous, S-type granites from the Georgetown Inlier yield crystallisation ages of ca. 1560–1550 Ma, whereas 100 km west of it, a newly identified Proterozoic Cudgee Creek Granite yield a crystallisation age of ca. 1540 Ma. The Cudgee Creek Granite is a HT , hybrid I−/A-type granite, reflecting a transitional geochemical trend towards the A-type granites in the Mount Isa Inlier further to the west. Zircon Lu Hf isotopic composition supports this geochemical trend with more radiogenic εHf (t) values from east to west, reflecting an increase in mantle input westward. The younging and the geochemical trend from the Georgetown Inlier S-type (ca. 1560–1550 Ma) to the I−/A- Cudgee Creek granite (ca. 1545 Ma) and the A-type granites in the Mount Isa Inlier (ca. 1530–1490 Ma) indicate progressive lithospheric thinning of the upper plate due to slow rollback of the Laurentian lower plate. These results suggest ongoing subduction drove hot and slow orogenesis involving slab rollback that was active for at least 100 m.y after the collisional stage. • Mesoproterozoic 1560–1490 Ma S-I-A-type magmatism occurred during lithospheric thinning of the Australian upper plate. • Lu Hf in magmatic zircon indicates an increase in juvenile material during mantle wedge opening due to slab rollback. • Nuna final assembly is associated with the formation of hot, wide slow-soft orogenic systems. [ABSTRACT FROM AUTHOR]

Integrated exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). The aim of this study was to provide the first assessment of exposure to PAHs in a large sample of the population in Queensland, Australia including exposure to infant (0–4 years). De-identified urine specimens, obtained from a pathology laboratory, were stratified by age and sex, and pooled (n = 24 pools of 100) and OH-PAHs were measured by gas chromatography–isotope dilution–tandem mass spectrometry. Geometric mean (GM) concentrations ranged from 30 ng/L (4-hydroxyphenanthrene) to 9221 ng/L (1-naphthol). GM of 1-hydroxypyrene, the most commonly used PAH exposure biomarker, was 142 ng/L. The concentrations of OH-PAHs found in this study are consistent with those in developed countries and lower than those in developing countries. We observed no association between sex and OH-PAH concentrations. However, we observed lower urinary concentrations of all OH-PAHs in samples from infants (0–4 years), children (5–14 years) and the elderly (> 60 year old) compared with samples from other age groups (15–29, 30–44 and 45–59 years) which may be attributed to age-dependent behaviour-specific exposure sources. [ABSTRACT FROM AUTHOR]

Production and distribution of fine roots (≤2.0 mm diameter) are central to belowground ecological processes. This is especially true where vegetation serves as a pump to prevent saturation of soil and possible drainage of excess water into or from potentially toxic waste material stored underground or in mounds aboveground. In this study undertaken near Sydney in Australia, we determined fine root biomass and evapotranspiration (ET) on a waste disposal site restored with either a 15-year-old grass sward or plantations of mixed woody species that were either 5 years old (plantation-5) with a vigorous groundcover of pasture legumes and grasses, or 3 years old (plantation-3) with sparse groundcover. These sites were compared with nearby remnant woodland; all four were located within 0.5-km radius at the same site. Ranking of fine root biomass was in the order woodland (12.3 Mg ha) > plantation-5 (8.3 Mg ha) > grass (4.9 Mg ha) > plantation-3 (1.2 Mg ha) and was not correlated with nutrient contents in soil or plants, but reflected the form and age of the vegetation covers. Trends in root length density (RLD) and root area index (RAI) followed those in root biomass, but the differences in RAI were larger than those in biomass amongst the vegetation covers. Annual ET in the dry year of 2009 was similar in the three woody vegetation covers (652-683 mm) and was at least 15% larger than for the grass (555 mm), which experienced restrained growth in winter and periodic mowing. This resulted in drainage from the grass cover while there was no drainage from any of the woody vegetation covers. In plantation-5, root biomass, RAI and RLD were reduced in the rain shadow side of the tree rows. Similarly, the amount and depth of rooting in the groundcover were reduced close to the trees compared to midway between rows. Differences in the root variables were larger than those in ET, which suggested that more roots were produced than were needed for water uptake and/or presence of considerable amounts of necromass. We conclude that vegetation covers, such as plantation-5 consisting of widely spaced trees and a heavy groundcover containing winter-active pasture legumes, will promote year-round water-use with a reduced risk of deep rooting that could breach buried wastes. This function could be sustained through progressive thinning of trees to account for not more than 25% of the whole canopy cover; this will minimize competition for limited soil-water and thereby constrain deep rooting as vegetation ages and attains climax. [ABSTRACT FROM AUTHOR]

• 1560 Ma TTG suite and migmatised mafic source exposed in NE Australia. • 'High-pressure' TTG generated at a depth of 25–35 km. • Field observations and trace-element modelling point to fluid-fluxed melting. • TTG chemical diversity reflects variable hydration, not depth. Across the Archaean to Proterozoic transition, the composition of newly-formed felsic continental crust changed from tonalite–trondhjemite–granodiorite (TTG) to calc-alkaline granitoid, possibly coinciding with the emergence of plate tectonics. Nevertheless, TTG suites were sporadically produced in Proterozoic and Phanerozoic orogenic belts, and such occurrences may provide petrological and tectonic insights into the formation of ancient continents. Here we demonstrate that the ca 1560 Ma Forest Home TTG plutonic suite in the Georgetown Inlier, NE Australia, was derived from partial melting of spatially-associated mafic rocks in a post-collisional setting. The studied TTG rocks have a 'high-pressure' geochemical signature, with elevated Sr, low heavy rare earth element and low high field strength element contents. Established petrogenetic models suggest they were derived by partial melting either of hydrated basaltic crust at >70 km depth or enriched lithospheric mantle, or by fractionation of lower-pressure mafic magmas. Using phase equilibrium calculations and trace-element modelling, we show that the geochemical signature of the Georgetown TTG likely resulted from fluid-fluxed crustal melting at relatively shallow depths (25–35 km), consistent with field observations and the inferred metamorphic evolution of the inlier. Our results suggest that the chemical variability of TTGs can reflect the variable availability of fluids rather than depth of melting, which has implications for tectonic processes responsible for the formation of early continental crust. [ABSTRACT FROM AUTHOR]

The final assembly of the Mesoproterozoic supercontinent Nuna was marked by the collision of Laurentia (North America) and Australia between c. 1.6 and 1.53 Ga. The final suture of Nuna has been identified in NE Australia, where the Proterozoic Georgetown Inlier represents the accreted leading edge of Laurentia. However, the structural and metamorphic evolution of the Georgetown Inlier remains uncertain. Here we investigate the orogenic evolution of this final Nuna collisional event using multi-scale petrostructural analysis, thermodynamic modelling, and geochronology. The Georgetown Inlier is characterised by c. 1.7 to 1.65 Ga metasedimentary and metabasic rocks that have been multiply deformed and metamorphosed, and intruded by c. 1.55 Ga S-type granites. Two pervasive fabrics (S1 and S2) are preserved within low strain domains of retrograde greenschist-facies foliations (S3 and S4). S1 is defined by greenschist-facies assemblages in the west, and by amphibolite-facies assemblages in the central Inlier, while S2 is defined by low-pressure and high-temperature mineral assemblages in the central and eastern inlier. Microstructural analysis combined with mineral chemistry and thermodynamic modelling in the central Inlier suggest prograde syn-S1 garnet growth in staurolite–garnet metapelites occurred at 530–550 ̊C at 5.4–6.4 kbar (core) to 620–660 ̊C at 8.6–9.8 kbar (rim). Garnet Lu–Hf geochronology dates this MP–MT metamorphism at c. 1.6 Ga. During the development of S2, staurolite was replaced by andalusite (M2a), which was pseudomorphed by sillimanite (M2b) in the eastern region, where granites are abundant. Calculations suggest 600–680 ̊C and 4–6 kbar for the sillimanite stage, and syn-S2 monazite yields c. 1.55–1.53 Ga U–Pb ages. Garnet in sillimanite-bearing metapelites is a MP–MT relict as its composition is reproduced in the staurolite stability field and it has a Lu–Hf age of c. 1.6 Ga. Field relationships suggest that the low–pressure stage was part of the regional thermal event associated with granite emplacement between c. 1.56–1.54 Ga. Some S-type granites record retrograde greenschist-facies foliations, and were emplaced late- to post-S2. In the eastern migmatitic complex, partial melting of paragneiss and amphibolite occurred early-, syn-, to post-S2. Peak conditions were estimated at 700–820 ̊C and 7.8–8.4 kbar in paragneiss, and at 750–890 ̊C and 7.0–8.4 kbar in garnet-free amphibolite.The P–T–d–t paths reconstructed for the Georgetown Inlier thus suggest an early deformation phase (D1) under MP–MT conditions at 1.6 Ga and a LP–HT metamorphic overprint during D2 between c. 1.56 and 1.53 Ga. These results support that the Georgetown Inlier records collisional orogenesis related to the final assembly of Nuna at 1.6 Ga, whereas the subsequent LP–HT overprint is interpreted as orogenic collapse. [ABSTRACT FROM AUTHOR]