David R. Gray's research while affiliated with University of Tasmania and other places

Publications (67)

Article
Full-text available
Collision, high-angle contraction, crustal thickening and heating at 555–516 Ma, primed the Damara Belt ready for crustal collapse, which was triggered by a transition to ENE–WSW contraction along the length of the belt in response to orogenic events in east Gondwana at 516–505 Ma. Along-orogen shortening reworked and thickened the high-grade core...
Article
Central Gondwana was assembled by three continental collisions in relatively quick succession: late Cryogenian East Africa Orogen, early Ediacaran West Antarctica Orogen and late Ediacaran Kuunga Orogen. The Kuunga Orogen involved diachronous closure of the South Adamastor–Khomas–Mozambique Oceans and accretion of Kalahari Craton and cratonic eleme...
Article
Metamorphic rocks form a minor component of the NE Arabian margin in Oman and the United Arab Emirates (UAE). Conditions span almost the entire range of crustal metamorphism from very high-P/low-T eclogite and blueschist to high-P/moderate-T epidote- to upper-amphibolite and low-P/high-T granulite facies. The NE Arabian margin experienced at least...
Article
The greater part of the metamorphic record of the Yilgarn Craton formed during a protracted middle Neoarchaean orogenic cycle, spanning from about 2750 to 2620 Ma. At least six distinct metamorphic events are defined by parageneses in different tectono-stratigraphic settings. This review characterizes the middle Neoarchaean metamorphic response of...
Article
Closure of the Neotethys Ocean and high-angle continent-continent collision between India and Asia after about 55 Ma resulted in low-angle subduction of the Indian plate below the Tibetan Plateau and by ~30 Ma established an arcuate 2300 km long, shallow north-dipping metamorphic fold-thrust belt in the foreland. This Himalayan Metamorphic Front qu...
Chapter
The Damara Orogenic System is a well-exposed orogenic junction that preserves a rich record of West Gondwana assembly and crustal processes in classic examples of transpression (Kaoko Belt) and bivergent collisional orogenesis (Damara Belt). Both belts show typical orogenic cycles in common with orogenic belts universally: from rifted passive margi...
Article
Damara Belt is well-exposed mid-crustal section through a collisional orogen of Cambrian age that closed the Khomas Ocean basin between passive margins on the Congo and Kalahari Cratons. Collision resulted in a bi-vergent orogen with distinct paired metamorphic pattern of foreland-vergent high-P/low-T orogenic margins and a broad high-grade, low-P/...
Article
Full-text available
Age calibrated deformation histories established by detailed mapping and dating of key magmatic time markers, are correlated across all tectono-metamorphic provinces in the Damara Orogenic System. Correlations across structural belts result in an internally consistent deformation framework with evidence of stress field rotations with similar timing...
Chapter
Convergent margin settings involving accretion of large turbidite fans with slivers of oceanic basement reflect important cites of continental crustal growth and recycling. Accreted crust consists of an upper layer of recycled arc and/or crustal detritus (turbidites) underlain by a layer of tectonically imbricated upper oceanic crust, and/or thinne...
Article
The exhumation of deep crustal rocks and juxtaposition of structural-metamorphic domains from different depths in a transpressional orogen may occur during the prograde evolution of the orogen by vertical extrusion or during the retrograde evolution of the orogen via extension. Metamorphic petrology, kinematics, and thermochronology of strike-slip...
Article
Full-text available
The Lachlan orogen developed as a classic accretionary orogen in an oceanic setting between the palaeo-Pacific subduction zone and the Australian craton. Direct evidence for the composition and age of the lower crust and the basement to the thick Palaeozoic turbidite fan of the Lachlan orogen is limited. Exposures of Cambrian metavolcanic rocks and...
Article
Investigation of material flow within transpressional orogens must involve integration of structural and metamorphic datasets. To illustrate the problems in documenting flow vectors we present integrated structural-metamorphic datasets from two transpressional systems; the Kaoko Belt in Namibia and the Kalinjala Shear Zone in South Australia. These...
Article
The Neoproterozoic–Cambrian Kaoko Belt is an orogen-scale (800 × 180 km) transpressional system important in the amalgamation of West Gondwana. Mid-crustal transpression at amphibolite to granulite facies conditions is dominated by two major, > 400 km exposed, strike-slip shear zones bounding a 20–40 km wide high-grade Orogen Core. To the east, a d...
Article
The Coastal Terrane, or westernmost part of the Kaoko Belt outboard of the Three Palms Mylonite Zone, has distinct feldspathic arenite sedimentary sequences, no basement, distinct ɛNd sediment signatures excluding the Archaean and suggesting Mesoproterozoic–Neoproterozoic provenance sources, and primitive arc-like geochemical signatures for I-type...
Article
Two syntectonic plutons of Cambrian age intruded Neoproterozoic metaturbidites in Namibia at the junction of the NS trending Kaoko and EW trending Damara belts. Sinistral transpression in the Kaoko Belt produced km-scale upright D1 folds overprinted by minor D2 folds. D3 is associated with N–S shortening in the Damara Belt. The plutons show two mai...
Article
Average orogenic strain rates may be calculated when it is possible to date mica cleavage or syndeformational veins and estimate fi nite strain. Deformation of accretionary-style thrust sheets in the western Lachlan Orogen occurred by chevron folding and faulting over an eastward propagating décollement. Based on 40 Ar/ 39 Ar dates of white micas,...
Chapter
Convergent margin tectonic settings involving accretion of large turbidite fans represent important sites of growth and regeneration of continental crust. The newly accreted continental crust consists of an upper crustal layer of recycled crustal detritus (turbidites) underlain by a lower crustal layer of tectonically imbricated oceanic crust, and/...
Article
The Himalayan Metamorphic Front consists of two basinal sequences deposited on the Indian passive margin, the Mesoproterozoic Lesser Himalayan Sequence and the Neoproterozoic–Cambrian Greater Himalayan Sequence. The current paradigm is that the unconformity between these two basinal sequences coincides with a crustal-scale thrust that has been call...
Article
Forty-three 40Ar/39Ar step-heating experiments on white mica, biotite, hornblende and whole rocks from the Damara Orogen, Namibia revise and refine the regional perspective on cooling, exhumation, and tectonic reactivation across the orogen. These data also document post-orogenic motion on major shear zones and the thermal effects of late-syn to po...
Article
Deformation in accretionary orogens, such as the eastern Australian Tasmanides, is clearly partitioned either as thin-skinned thrusting or thick-skinned faulting, with structural style dependent on the nature and stratal thicknesses of the sequences involved. The thin-skinned thrust systems consist of either detachment-related folds and thrust shee...
Article
The Saih Hatat domal culmination of the Oman Mountains, Arabian Peninsula contains a major, refolded, NE-facing, recumbent, anticlinal fold-nappe within Pre-Ordovician sedimentary cover (autochthon) and Mesozoic platform carbonates that underlie the Samail and Hawasina nappes. Tracts of overturned stratigraphy covering over a 1000 km2 are associate...
Article
Zircon and monazite U–Pb dates, garnet Sm–Nd dates and hornblende 40 Ar/ 39 Ar data from the transpressional Kaoko Belt of the late Neoproterozoic Pan-African Orogenic system confirm three distinct tectono-metamorphic cycles: M1 (655–645 Ma), M2 (580–550 Ma) and M3 (535–505 Ma). The high-grade M1 metamorphic cycle and associated intrusive complexes...
Article
Igneous zircons in felsic schist, or metatuff, infolded with mafic schist, calcschist, and quartz mica schist of the As Sifah lower plate window, NE Oman, have yielded a U/Pb SHRIMP crystallization age of 298 +/- 3 Ma. The metatuff was previously considered to represent Permian bimodal volcanism, but these data indicate that the magmatism is older...
Article
Full-text available
The Pan-African Kaoko Belt of NW Namibia provides a well- exposed example of material flow in the evolving middle and lower crust during sinistral transpressional orogenesis. The Kaoko Belt is a composite metamorphic belt with shear zone bounded zones of contrasting metamorphic style that were metamorphosed at approx- imately the same time (575-550...
Article
New 40Ar/39Ar data from sedimentary rock-hosted orogenic gold deposits in northeastern Tasmania constrain most ore formation to between 395Ma and 385Ma. These 385–395Ma ages for the formation of orogenic gold agree well with an inferred Early to Middle Devonian timing for peak deformation and folding across much of northeastern Tasmania. Data from...
Article
The inversion of the Neoproterozoic-Cambrian passive margin of East Gondwana occurred during the early Paleozoic Delamerian-Ross orogeny. We present 40Ar/39Ar and structural data from deformed and metamorphosed Neoproterozoic clastic rocks beneath the Tasmanian ophiolite and the footwall of a high-pressure metamorphic complex in northern Tasmania....
Article
Controversy over the age of peak metamorphism and therefore the tectonic evolution of the Arabian margin relates to the polydeformed and polymetamorphosed nature of glaucophane-bearing eclogites from the Saih Hatat window beneath the allochthonous Samail ophiolite in NE Oman. These eclogites contain relicts of earlier fabrics, structures and metamo...
Article
Full-text available
The northern margin of the Inland Branch of the Pan-African Damara Orogen in Namibia shows dramatic along-strike variation in metamorphic character during convergence between the Congo and Kalahari Cratons (M3 metamorphic cycle). Low-P contact metamorphism with anticlockwise P-T paths dominates in the western domains (Ugab Zone and western Northern...
Article
Poly-deformed and poly-metamorphosed glaucophane-eclogite mega-boudins beneath the Samail Ophiolite, Oman record an early subduction-related high-P metamorphism as well as subsequent overprinting deformation and metamorphism related to exhumation. Previously published Rb/Sr ages of 78 Ma and 40Ar/39Ar ages of 82–79 Ma record the major NE-directed s...
Article
Slivers of dismembered Cambrian ophiolites are preserved in major fault zones of the turbidite-dominated, western and central Lachlan Orogen of southeastern Australia. Geometrical, chronological, and metamorphic constraints indicate that these slivers did not undergo classic Tethyan-style obduction but were incorporated into evolving turbidite wedg...
Article
The Kaoko Belt portion of the Damara Orogen, Namibia, is the deeply eroded core of a sinistral transpressional orogen that has half-flower structure geometry centred on the major, 4–5-km-wide Purros Mylonite Zone. Formed between the Congo Craton in the east and Rio De La Plata Craton in Brazil, the Kaoko Belt represents the northern coastal arm of...
Article
Full-text available
The Kaoko Belt in Namibia represents the deeply eroded core of a classic sinistral transpressional orogen with a half flower structure centred on the crustal-scale Purros Mylonite Zone. The Kaoko Belt consists of three NW-trending structural zones each with distinct kinemetamorphic style. The Eastern Kaoko Zone contains upright-folded, Neoproterozo...
Article
The preservation of diverse ophiolitic rocks in the Tasmanides of eastern Australia reflects a period of complex oceanic crust formation off the cast Gondwana margin from e. 560 to 495 Ma. This involved development of oceanic crust possibly at a spreading ridge (now preserved as the c. 560 Ma Marlborough ophiolite, New England Orogen), development...
Article
More than 600 stable isotope analyses from veins and their metasedimentary host rocks from the Ouachita orogenic belt of Arkansas and Oklahoma provide an opportunity to study fluid-rock interaction processes associated with vein formation during deformation and low-grade regional metamorphism. The δ18O values of vein quartz vary from 16.0 to 26.4‰,...
Article
Placing ore formation within the overall tectonic framework of an evolving orogenic system provides important constraints for the development of plate tectonic models. Distinct metallogenic associations across the Palaeozoic Lachlan Orogen in SE Australia are interpreted to be the manifestation of interactions between several microplates and three...
Article
Full-text available
Stress analysis of dikes and kinematic analysis of faults within the Tavua Volcano of Viti Levu, Fiji, indicate an apparent migration of the causative maximum principal stress axis (σ1) from NW toward north between ∼5.0 and <3.9 Ma. The dikes and faults are part of successive structural and magmatic events at the arc scale. We present data on the c...
Article
Saih Hatat contains tiered sets of low-angle structural breaks that reflect a complex stacking of sheets, which requires multiple upward movement of units within an unstable orogenic wedge in a convergent setting. Early recumbent folds within the Saih Hatat window are subparallel to, but cut by, a major low-angle contractional fault (décollement) t...
Conference Paper
Full-text available
Assembly of eastern Australia involved inversion of continental margin sequences and intracratonic rifts, collision with Proterozoic continental fragments and island arcs, and accretion of submarine fans. This occurred along the Pacific margin of Gondwana from early Paleozoic to Mesozoic times, and produced crust of continental thickness and charac...
Conference Paper
Full-text available
Assembly of eastern Australia involved inversion of continental margin sequences and intracratonic rifts, collision with Proterozoic continental fragments and fringing arcs, and accretion of submarine fans. This occurred along the Pacific margin of Gondwana from early Paleozoic to Mesozoic times, and produced crust of continental thickness and char...
Article
Fault zones within turbidite-dominated orogenic systems, typified by the Lachlan Orogen of eastern Australia, are characterised by higher than average strain and intense mica fabrics, transposition foliation and isoclinal folds, poly-deformation with overprinting crenulation cleavages, and steeply to moderately plunging meso- and micro-folds. They...
Article
The Lachlan Fold Belt (Lachlan Orogen) of eastern Australia was part of a Paleozoic convergent plate margin that stretched around the supercontinent of Gondwana from South America to Australia. Lower Paleozoic (545–365 Ma) deep-water, quartz-rich turbidites, calcalkaline volcanic rocks, and voluminous granitic plu-tons dominate the Lachlan Orogen....
Article
Late stage extensional character of the Samail Ophiolite, as inferred from structure within the Ibra-Dasir blocks, supports gravity-driven final emplacement for the ophiolite. This however, is not related to 'collapse' off ramp-related domal culminations as speculated in Late Cretaceous thrusting scenarios. Domal structures of the Oman Mountains ar...
Article
The Oman Mountains preserve evidence for a long-lived, kinematically coherent, tectonic "event" linked to the emplacement of the Oman ophiolite. Three windows (Hawasina, Jabal Akhdar, and Saih Hatat) hold the keys to the puzzle of the ophiolite obduction and the tectonic development of this part of the Arabian Peninsula. In the southeasternmost Sai...
Article
Ar-Ar data from fabric-forming white mica in slates, syntectonic quartz veins and granitic mylonites constrain the timing of metamorphism, deformation, and exhumation in the Lachlan orogen, Australia. These data also help define the tectonic evolution of the Tasmanides during Paleozoic time. The Lachlan orogen formed by the progressive accretion of...
Article
Mélange formation, cataclasis, meso- to micro-scale faulting, and veining reflect faulting processes within turbidite and limestone sequences juxtaposed along a steeply dipping, sinistral wrench-fault zone in the Lachlan Orogen, southeastern Australia. Fault damage occurs across a zone up to 600 m wide. Effects of faulting in the turbidites are sho...
Article
Upper-crustal elements of the ∼35 km thick crust of the southern portion of the Lachlan Orogen consist of a chevron-folded and faulted turbidite package (15 to 17 km structural thickness) overlying imbricated Cambrian metabasites and cherts (∼5 km structural thickness). These are intruded by both Early and Late Devonian granites and are overlain by...
Article
Continental crustal rocks, now structurally beneath the allochthonous Samail ophiolite, underwent blueschist to eclogite facies metamorphism prior to the emplacement of the Oman ophiolite onto the Arabian margin. The recognition of a major low angle fault within this polydeformed and polymetamorphosed sequence of metacarbonates, metabasites, quartz...
Article
Geochemical studies have been conducted on the Waratah Fault Zone, a steep, NE–SW-trending brittle fault zone in the southeastern Lachlan Fold Belt, Australia. Strike-slip movement along the fault juxtaposed an Early Devonian turbidite sequence (Liptrap Formation) against heavily veined Early Devonian limestones. The fault zone consists of the faul...
Article
– data constrain the history of metamorphism, deformation and mineralization in the western subprovince of the Lachlan Fold Belt. Rocks in the Mount Stavely Volcanic Complex and the Bushy Creek Pluton give – ages of about 500 Ma for hornblende and biotite. The dates from the Mount Stavely Volcanic Complex limit the age of mineralization in the meta...
Article
Full-text available
Divergent double subduction, involving removal of an oceanic basin from both sides and collision, has distinct fingerprints of magmatism and significant implications for the tectono-magmatic evolution of orogenic belts. The complete evolution of a divergent double subduction system involves four stages: (1) initial interaction between the two diver...
Article
The Lachlan Fold Belt of southeastern Australia is a 700km wide belt of deformed, Palaeozoic deep and shallow marine sedimentary rocks, cherts, and mafic volcanic rocks. Characterized by large areas of chevron-folded turbidite sequences, linked contractional and strike-slip faults, and superposed thrust-belts of different age and vergence, it has l...
Chapter
Most slates undergo an approximately constant volume (< 10% loss), plane strain, coaxial deformation during development of slaty cleavage. Strain analysis data from pressure shadows and graptolites in slates from the Martinsburg Formation, USA, and the Lachlan Fold Belt, eastern Australia, form part of a new strain data set to characterize tectonic...
Article
Chaotic block-in-matrix melange, broken formation along high strain zones associated with large scale imbrication, early bedding-parallel cleavage, recumbent folds in turbidites, and structural complexity in cherts are key elements of a mid-Palaeozoic subduction complex in the eastern part of the Lachlan Fold Belt, southeastern Australia. The compl...
Article
Emplacement of an upper crustal, leading imbricate-fan thrust belt in the Lachlan Fold Belt of eastern Australia was accomplished along a 0.5–1 km thick zone of heterogeneously deformed, low grade phyllonite in pelitic rock. Continuous recrystallization and neocrystallization of mica in a zone of transposition layering has provided a weak zone at t...
Article
Studies on shape changes in deformed Oncograptus upsilon combined with strain analysis of pressure shadows around framboidal pyrite revealed that a small volume change of the order of 5 percent accompanied the cleavage development in the shales from Gisborne, Victoria. Starting from the proximal end, Oncograptus upsilon exhibits progressive increas...
Article
Sandstone layers within tightly chevron-folded quartz-rich turbidites of the Lachlan Fold belt southeastern Australia show a fanning spaced cleavage overprinted by a non-fanning grain alignment cleavage, low internal strains recorded by quartz grain separations (XZ ≈ 1.4−1.8) and low fold flattening strains (XZ < 1.8). Angular relations between spa...
Article
Crustal evolution of the Lachlan Fold Belt of southeastern Australia has involved the mobilisation of significant melt volumes now preserved as granites, suggesting that large parts of the lower crust were at T > 800°C for part of the thermal evolution. This anomalous thermal activity has been variously related to continental extension, magmatic un...
Article
An E-directed, imbricate-fan thrust-system within a chevron-folded, monotonous quartz-rich turbidite succession shows marked gradients in strain from the upper to lower parts of individual thrust-sheets. Upper parts of thrust-sheets show low to moderate strains (XZ strains < 5.0:1), subvertical extensions defined by straight quartz-fibres in pressu...
Article
Quartz vein 18O/16O ratios across a 500 km transect through the Lachlan fold belt of southeastern Australia are remarkably uniform (+/-1-1.5 permil) at both local (centimeter to meter) and regional (over 104 km2) scales. They define isotopic zones that correlate with the tectonic divisions of the Cambrian through Devonian (dominantly Ordovician) qu...
Article
The Tabberabbera district of the southeast Lachlan Fold Belt has a good example of a complex fold pattern produced by folding of angular unconformable sequences. Ordovician quartz flysch (Hotham Group) contains subhorizontal, upright, tight, easterly trending folds of Early to Middle Silurian age. These have been reoriented by a locally intense Mid...
Article
Almost all published balanced cross-sections include cleaved and/or strained rocks and may therefore violate the requirement that bed-lengths and formation areas are preserved between undeformed and deformed states. Knowledge of distortions, presence and type of cleavage, and overprinting relations in poly-deformed segments are necessary to define...

Citations

... Consequently, the overlapping ages between illite extracted from mylonites and shear-zone-parallel fault gouges can be interpreted as the progression of deformation from ductile to brittle conditions during the late Brasiliano Orogeny. On the other hand, subsequent Early to Middle Paleozoic reactivations, including faults cross-cutting the mylonitic foliation, are more likely to record a multiphase evolution related to adjacent basin evolution and far-field effects of the proto-Pacific subduction along southwestern Gondwana (e.g., Hueck et al., 2017Hueck et al., , 2019Hueck et al., , 2020Goscombe et al., 2022). ...
... However, studies on multiple transects in the Himalaya over the past 20 years have shown that two or more metamorphic rock sheets in the GHC were exhumed at different times. Within these new tectonic-metamorphic discontinuities, one discontinuity has similar activity ages and spatial distributions across various transects, known as the High Himalayan Thrust (HHT) (Kohn et al., 2004;Carosi et al., 2010Carosi et al., , 2018Imayama et al., 2012;Montomoli et al., 2013;Wang JM et al. al., 2015a, 2016Goscombe et al., 2018). This observation challenges the traditional orogenic models based on single stage exhumation and the present Himalayan architecture. ...
... The internal kinematic zone of the Irumide Belt (sensu Daly 2007), where the Mkushi district lies, is characterized by a series of domal structures comprising intensely deformed and metamorphosed Mkushi gneiss and associated granite gneiss tectonically interleaved with Muva Supergroup siliciclastic rocks. These structures formed during thrust events driven by northwest-directed ductile displacement of the basement and associated cover rocks during the Irumide Orogeny at ~ 1046-1020 Ma , 2008Daly 2007;Goscombe et al. 2020). Peak metamorphism at ~ 1020 Ma was accompanied by voluminous high-K, S-type, granitic magmatism between 1050 and 950 Ma, with a major pulse at ~ 1015 Ma (De Waele et al. 2005, to which the Mtuga granite (Fig. 2a) and other felsic bodies of the Mkushi district, plus numerous porphyritic intrusions in the larger Mkushi area, have been assigned (Rainaud et al. 2005;De Waele and Mapani 2002;De Waele et al. 2009). ...
... The HP rocks include the structurally deepest level eclogites at As Sifah, the intermediate Hulw blueschsists, the carpholite-bearing meta-sediments and lawsonite-bearing meta-basalts of the Ruwi mélange, and underlying shelf carbonate units, also containing carpholite (Wadi Mayh, Yenkit, Yiti, Al Khuyran units). Widespread regional 'extensional' top-to-NNE ductile shear S-C fabrics and other kinematic indicators relate to SSWextrusion of footwall HP rocks in a wholly compressional environment (Searle et al., 1994(Searle et al., , 2004Agard et al., 2010;Yamato et al., 2007;Garber et al., 2021), not to any SW-directed subduction (Gregory et al., 1998;Gray et al., 2000Gray et al., , 2004Miller et al., 2002;Goscombe et al., 2020), or to crustal extension related to orogenic collapse (Mattern and Scharf, 2018;Scharf et al., 2019). ...
... Limited available metamorphic ages indicate that rocks now exposed at the surface in the northern Narryer Terrane south of the Errabiddy Shear Zone and in the eastern part of the terrane lay at respective depths of 25-35 km (7-10 kbar) at 2.66-2.62 Ga and 15-19 km (4-5 kbar) at ∼2.7 Ga and were uplifted at ∼2 Ga during the Glenburgh Orogeny (Goscombe et al., 2019;Muhling et al., 2008). T1 likely accommodated significant uplift during this time but it does not reach the surface, and detailed structural analysis of the Jack Hills greenstone belt and surroundings so far did not reveal evidence for structures of Glenburgh age at the present day surface (Spaggiari, 2007;Spaggiari et al., 2008). ...
... Subsequently, the region was deformed and weakly metamorphosed during the Damaran/Pan-African orogeny, roughly between 590 and 500 Ma. This included the intrusion of several smaller granite bodies (Goscombe et al. 2018). Gärtner et al. (2014) and Garzanti et al. (2017) compared the U-Pb ages of detrital zircon collected from contemporary sediments of the Kunene and Cubango (Okavango) rivers at the Angolan-Namibian border. ...
... The regional tectonic evolution encompassed two or three or up to seven deformation phases, although a correlation of these in different parts of the belt is not without problems (e.g Miller, 1983Miller, , 2008Kisters et al., 2004;Kisters et al., 2012;Goscombe et al., 2017). Early, low-angle fabrics and associated nappes are commonly related to a D 1 deformation thought to be associated with northward subduction of the Kalahari Craton below the Congo Craton. ...
... The orogenesis of the Kaoko Belt comprises two main phases, the Kaoko Phase (590-535 Ma) and the Damara Phase (555-505 Ma), both part of the Damara orogeny (Goscombe et al., 2017;Goscombe et al., 2003). The Kaoko Belt is considered a classic example of an oblique transpressional orogenic belt and is the result of the collision of the Congo, Kalahari and Rio De La Plata cratons (Goscombe et al., 2017;Porada, 1989;Prave, 1996;Trompette, 1997). ...
... In general, juvenile continental material is considered to be plutonic rocks produced by arc magmatism, so an ocean basin should not be, strictly speaking, referred to as juvenile material. Nonetheless, even if they are not new continental material, trapped ocean basins are still volumetrically important material for continental growth, as mentioned in many studies (Foster & Goscombe, 2013;Foster et al., 2014). Although estimating the total contribution to the Junggar continental crust through the addition of the oceanic basement is beyond the capability of the two-dimensional result in this study, we can still estimate its contribution efficiency along the island arc axis. ...
... The HP rocks include the structurally deepest level eclogites at As Sifah, the intermediate Hulw blueschsists, the carpholite-bearing meta-sediments and lawsonite-bearing meta-basalts of the Ruwi mélange, and underlying shelf carbonate units, also containing carpholite (Wadi Mayh, Yenkit, Yiti, Al Khuyran units). Widespread regional 'extensional' top-to-NNE ductile shear S-C fabrics and other kinematic indicators relate to SSWextrusion of footwall HP rocks in a wholly compressional environment (Searle et al., 1994(Searle et al., , 2004Agard et al., 2010;Yamato et al., 2007;Garber et al., 2021), not to any SW-directed subduction (Gregory et al., 1998;Gray et al., 2000Gray et al., , 2004Miller et al., 2002;Goscombe et al., 2020), or to crustal extension related to orogenic collapse (Mattern and Scharf, 2018;Scharf et al., 2019). ...