1.6 Ga crustal thickening along the final Nuna suture

Pourteau, Amaury; Smit, Matthijs; Li, Zheng‐Xiang; Collins, William J.; Nordsvan, Adam R.; Volante, Silvia; Li, Jiangyu

doi:10.1130/g45198.1

Cited by 86 publications

(74 citation statements)

References 34 publications

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“…See text for details. Grey field corresponds to typical P – T gradients found in collisional orogens (after Pourteau et al., ). Red and blue arrows highlight the heating and cooling paths respectively…”

Section: Discussionmentioning

confidence: 99%

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Mesozoic to Cenozoic tectono‐metamorphic history of the South Pamir–Hindu Kush (Chitral, NW Pakistan): Insights from phase equilibria modelling, and garnet–monazite petrochronology

Soret

Larson

Cottle

et al. 2019

Journal Metamorphic Geology

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The Karakoram–Hindu Kush–Pamir and adjacent Tibetan plateau belt comprise a series of Gondwana‐derived crustal fragments that successively accreted to the Eurasian margin in the Mesozoic as the result of the progressive Tethys ocean closure. These domains provide unique insights into the thermal and structural history of the Mesozoic to Cenozoic Eurasian plate margin, which are critical to inform the initial boundary conditions (e.g. crustal thickness, structure and thermo‐mechanical properties) for the subsequent development of the large and hot Tibetan–Himalaya orogen, and the associated crustal deformation processes. Using a combination of microstructural analyses, thermobarometry modelling and U–Th–Pb monazite and Lu–Hf garnet geochronology, the study reappraises the metamorphic history of exposed mid‐crustal metapelites in the Chitral region of the South Pamir–Hindu Kush (NW Pakistan). This study also demonstrates that trace elements in monazite (especially Y and Dy), combined with thermodynamical modelling and Lu–Hf garnet dating, provides a powerful integrated toolbox for constraining long‐lived and polyphased tectono‐metamorphic histories in all their spatial and temporal complexity. Rocks from the Chitral region were progressively deformed and metamorphosed at sub‐ and supra‐solidus conditions through at least four distinct episodes from the Mesozoic to the Cenozoic. Rocks were first metamorphosed at ~400–500°C and ~0.3 GPa in the Late Triassic–Early Jurassic (210–185 Ma), likely in response to the accretion of the Karakoram during the Cimmerian orogeny. Pressure and temperature subsequently increased by ~0.3 GPa and 100°C in the Early‐ to Mid Cretaceous (140–80 Ma), coinciding with the intrusion of calcalkaline granitic plutons across the Karakoram and Pamir regions. This event is interpreted as the record of crustal thickening and the development of a proto‐plateau within the Eurasian margin due to a long‐lived episode of slab flattening in an Andean‐type margin. Peak metamorphism was reached in the Late Eocene–Early Oligocene (40–30 Ma) at conditions of 580–600°C and ~0.6 GPa and 700–750°C and 0.7–0.8 GPa for the investigated staurolite schists and sillimanite migmatites respectively. This crustal heating up to moderate anatexis likely resulted in the underthrusting of the Indian plate after a NeoTethyan slab‐break off or to the Tethyan Himalaya–Lhasa microcontinent collision and subsequent oceanic slab flattening. Near‐isothermal decompression/exhumation followed in the Late Oligocene (28–23 Ma) as marked by a pressure decrease in excess of ~0.1 GPa. This event was coeval with the intrusion of the 24 Ma Garam Chasma leucogranite. This rapid exhumation is interpreted to be related to the reactivation of the South Pamir–Karakoram suture zone during the ongoing collision with India. The findings of this study confirm that significant crustal shortening and thickening of the south Eurasian margin occurred during the Mesozoic in an accretionary‐type tectonic setting through successive episodes of...

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Section: Discussionmentioning

confidence: 99%

“…See text for details. Grey field corresponds to typical P-T gradients found in collisional orogens (after Pourteau et al, 2018). Red and blue arrows highlight the heating and cooling paths respectively Ti-in-Bt (Sil) Ti-in-Bt (St) Grt-Bt (Sil) Grt-Bt (St) GBMP (OG) GBMP (OR) GASP (IR) GASP (OR)…”

Section: P-t-d Historymentioning

confidence: 99%

Mesozoic to Cenozoic tectono‐metamorphic history of the South Pamir–Hindu Kush (Chitral, NW Pakistan): Insights from phase equilibria modelling, and garnet–monazite petrochronology

Soret

Larson

Cottle

et al. 2019

Journal Metamorphic Geology

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“…Co-location of the arc and backarc assemblages of southern Laurentia inboard of the same west-dipping subduction zone that formed the backarc basins of Paleoproterozoic eastern Australia-Antarctica provides answers to two interrelated and fundamental questions: 1) the remarkably similar timing and periodicity of events in two now widely separated continents, and 2) the whereabouts of the magmatic arc that formed contemporaneously with backarc extension from 1800 to 1655 Ma along the Australian-Antarctic margin but which appears to no longer reside in either Australia or Antarctica. Similarities in timing might alternatively be explained as the result of far-field forces operating at plate scale, but this argument is increasingly difficult to sustain in light of other aspects of the shared geology, including matching early intrusive-related low pressure-high temperature metamorphism and superposed anticlockwise pressure-temperature-time paths consistent with periodic crustal thickening followed by extensional exhumation and isobaric cooling (Boger and Hansen, 2004;Grambling et al, 1989;Pourteau et al, 2018;Rubenach et al, 2008). A more likely scenario is that the Laurentian provinces represent the more outboard and distal component of the same arc-backarc system that developed along the Australian-Antarctic margin from 1800 to 1655 Ma (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The deepest part of this sequence was deposited in Georgetown and the eastern part of the Curnamona province, which then served as the trailing edge of the Australian-Antarctic continent. This common record of basin formation and shared geological history would appear to preclude alternative interpretations in which the Georgetown Province is postulated to have originated in western North America (Boger and Hansen, 2004;Nordsvan et al, 2018;Pourteau et al, 2018). Following, and possibly partly overlapping deposition of this post-rift sedimentary package, much of the Australian-Antarctic margin was again subjected to increased amounts of tectonic instability from ca.…”

Section: Short Researchmentioning

confidence: 99%

Antipodean fugitive terranes in southern Laurentia: How Proterozoic Australia built the American West

Gibson

Champion

2019

Lithosphere

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Paleoproterozoic arc and backarc assemblages accreted to the south Laurentian margin between 1800 Ma and 1600 Ma, and previously thought to be indigenous to North America, more likely represent fragments of a dismembered marginal sea developed outboard of the formerly opposing Australian-Antarctic plate. Fugitive elements of this arc-backarc system in North America share a common geological record with their left-behind Australia-Antarctic counterparts, including discrete peaks in tectonic and/or magmatic activity at 1780 Ma, 1760 Ma, 1740 Ma, 1710–1705 Ma, 1690–1670 Ma, 1650 Ma, and 1620 Ma. Subduction rollback, ocean basin closure, and the arrival of Laurentia at the Australian-Antarctic convergent margin first led to arc-continent collision at 1650–1640 Ma and then continent-continent collision by 1620 Ma as the last vestiges of the backarc basin collapsed. Collision induced obduction and transfer of the arc and more outboard parts of the Australian-Antarctic backarc basin onto the Laurentian margin, where they remained following later breakup of the Neoproterozoic Rodinia supercontinent. North American felsic rocks generally yield Nd depleted mantle model ages consistent with arc and backarc assemblages built on early Paleoproterozoic Australian crust as opposed to older Archean basement making up the now underlying Wyoming and Superior cratons.

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“…In the last two decades, two Proterozoic supercontinents, Nuna (or Columbia) and Rodinia, have widely attracted the attention of the geological community (e.g., Evans, ; Li, Bogdanova, et al, ; Rogers & Santosh, ; Wan et al, ; Zhao et al, , ). The generic model for the Nuna evolution is that this supercontinent assembled between 2.0 and 1.6 Ga, accretion took place along some of its outside margins between 1.8 and 1.3 Ga, the interior of the supercontinent was affected by extension between 1.6 and 1.3 Ga, and finally, breakup took place around 1.3 Ga (Nordsvan et al, ; Pisarevsky et al, ; Pourteau et al, ; Zhao et al, , ). The fragments from the breakup of Nuna were then reamalgamated to form Rodinia at ca.…”

Section: Introductionmentioning

confidence: 99%

From Breakup of Nuna to Assembly of Rodinia: A Link Between the Chinese Central Tianshan Block and Fennoscandia

et al. 2019

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The transition from breakup of Nuna (or Columbia, 2.0-1.6 Ga) to assembly of Rodinia (1.0-0.9 Ga) is investigated by means of U-Pb and Lu-Hf data of detrital zircons from three Neoproterozoic metasedimentary rocks in the Central Tianshan Block (CTB), NW China. These data yield six age peaks around 1.0, 1.13, 1.34, 1.4-1.6, 1.75, and 2.6 Ga. Few zircons are detected between 2.0 and 2.5 Ga. The Paleoproterozoic to Neoproterozoic detrital zircons have Hf isotopic compositions (−22.1 to +13.0) similar to those of coeval magmatic rocks in the CTB, indicating a proximal provenance. These results, together with the geological evidence and the presence of 1.4 Ga orogenic granitoids in the CTB, rule out most cratons as the CTB sources but support a Fennoscandia ancestry. Zircon U-Pb ages and Hf isotopic compositions from the CTB and Fennoscandia suggest that from 1.8 to 1.4 Ga, the ε Hf (t) values increased toward more positive values, consistent with an exterior orogen characteristic that the lower crust was replaced by a juvenile arc crust. In contrast, from 1.4 to 0.9 Ga, zircon ε Hf (t) values decreased to more negative values, reflecting an interior orogen, characterized by enhanced contribution of recycled crustal material from collided continental fragments. This marked shift most likely reflected a transition from breakup of Nuna to assembly of Rodinia, accomplished by a transformation from an exterior orogen to an interior one.

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1.6 Ga crustal thickening along the final Nuna suture

Cited by 86 publications

References 34 publications

Mesozoic to Cenozoic tectono‐metamorphic history of the South Pamir–Hindu Kush (Chitral, NW Pakistan): Insights from phase equilibria modelling, and garnet–monazite petrochronology

Mesozoic to Cenozoic tectono‐metamorphic history of the South Pamir–Hindu Kush (Chitral, NW Pakistan): Insights from phase equilibria modelling, and garnet–monazite petrochronology

Antipodean fugitive terranes in southern Laurentia: How Proterozoic Australia built the American West

From Breakup of Nuna to Assembly of Rodinia: A Link Between the Chinese Central Tianshan Block and Fennoscandia

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