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The crustal evolution of the Yangtze block and its tectonic affinity to other continents of Rodinia and subsequent Gondwana have not been well constrained. Here, we present new U-Pb ages and Hf isotopes of detrital zircons from the late Neoproterozoic to early Paleozoic sedimentary rocks in the northwestern margin of the Yangtze block to provide critical constraints on their provenance and tectonic settings. The detrital zircons of two late Neoproterozoic samples have a small range of ages (0.87-0.67 Ga) with a dominant age peak at 0.73 Ga, which were likely derived from the Hannan-Micangshan arc in the northwestern margin of the Yangtze block. In addition, the cumulative distribution curves from the difference between the depositional age and the crystalline age (CA-DA) together with the mostly positive εHf(t) values of these zircon crystals (-6.8 to +10.7, ~90% zircon grains with εHf[t] > 0) suggest these samples were deposited in a convergent setting during the late Neoproterozoic. In contrast, the Cambrian--Silurian sediments share a similar detrital zircon age spectrum that is dominated by Grenvillian ages (1.11-0.72 Ga), with minor late Paleoproterozoic (ca. 2.31-1.71 Ga), Mesoarchean to Neoarchean (3.16-2.69 Ga), and latest Archean to early Paleoproterozoic (2.57-2.38 Ga) populations, suggesting a significant change in the sedimentary provenance and tectonic setting from a convergent setting after the breakup of Rodinia to an extensional setting during the assembly of Gondwana. However, the presence of abundant Grenvillian and Neoarchean ages, along with their moderately to highly rounded shapes, indicates a possible sedimentary provenance from exotic continental terrane(s). Considering the potential source areas around the Yangtze block when it was a part of Rodinia or Gondwana, we suggest that the source of these early Paleozoic sediments had typical Gondwana affinities, such as the Himalaya, north India, and Tarim, which is also supported by their stratigraphic similarity, newly published paleomagnetic data, and tectono-thermal events in the northern fragments of Gondwana. This implies that after prolonged subduction in the Neoproterozoic, the northwestern margin of the Yangtze block began to be incorporated into the assembly of Gondwana and then accept sediments from the northern margin of Gondwanaland in a passive continental margin setting. [ABSTRACT FROM AUTHOR]

Published U-Pb-Hf values for detrital zircons of Mesoproterozic age in Cambrian and Ordovician strata of the Argentina Precordillera and San Rafael Block of the Cuyania Terrane overlap extensively with values from Grenville/Appalachian detritus and the Granite-Rhyolite Province of Laurentia and with values from Sierra de Maz and Sierra de Pie de Palo of the Western Sierras Pampeanas (WSP) of western Argentina. These data have been interpreted as evidence of the Laurentian origin of Cuyania and the WSP. However, U-Pb and corresponding εHf values presented here for Mesoproterozoic zircons from Ediacaran sandstones deposited on the Río de la Plata Craton (RPC) are markedly similar to those of Mesoproterozoic zircons from Laurentia, Cuyania, and the WSP, thus contradicting the previous interpretation. Given the geotectonic history of southwestern Gondwana, the U-Pb-Hf values from the Mesoproterozoic zircons of the Piedras de Afilar and Cerro Largo Formations of the RPC are consistent with a proto-Andean Mesoproterozoic belt on the western margin of the RPC. This belt would have served as the basement and thus the provenance of Mesoproterozoic detrital zircons in Cuyania and the WSP. The existence of this Mesoproterozoic belt introduces a different paradigm for interpreting the late Neoproterozoic to early Paleozoic geotectonic history of the proto-Andean margin of Gondwana and renders Neoproterozoic–early Paleozoic transfers of a Sierra de Maz–Arequipa–Rio Apa Terrane and the Cuyania Terrane from Laurentia unnecessary. [ABSTRACT FROM AUTHOR]

Abstract: We report the first study integrating in situ U–Pb and Hf isotope data from magmatic zircon and whole-rock Sm–Nd isotope data for granitic rocks of the Sierras Pampeanas, Argentina, in order to evaluate the Palaeozoic growth of the proto-Andean margin of Gondwana. Early–Middle Ordovician granitic magmatism is by far the most voluminous of the Sierras Pampeanas and represents the most significant magmatic event. These calc-alkaline granitoids were intruded at an active continental margin. εHft values range from −3.3 to −14.7 and εNdt from −3.3 to −6.3 (t=473Ma), with average TDM Hf and TDM Nd ranging from 1.5 to 2.2Ga and 1.4 to 1.7Ga, respectively. Middle–Late Devonian magmatism occurred in the foreland, away from the orogenic front in the west, and included F-U-REE rich A-type granites. The Achala granite, the largest batholith in the Sierras Pampeanas, has εHft and εNdt values ranging from −3.6 to −5.8 and −4.0 to −6.5, respectively (t=369Ma). Small scattered Early Carboniferous A-type granite plutons were intruded in a dominantly extensional setting and have εHft and εNdt values ranging from −6.7 to +2.2 and −0.5 to −3.6, respectively (t=341Ma). The generation of Ordovician and Devonian magmas dominantly involved crustal reworking and stabilization rather than the formation of new continental crust by juvenile material accretion, whereas Carboniferous magmatism resulted in part from reworking of supracrustal material, but with variable addition of juvenile magmas. [Copyright &y& Elsevier]

Abstract: The leucogranites in the Baoshan Block of the Tethyan belt in Western Yunnan, are composed mainly of two-mica granite with subordinate muscovite granite. Here we present zircon U–Pb ages from four intrusions that show ages of 448–476Ma suggesting that these rocks were emplaced during the Ordovician. The leucogranites are high-K calc-alkaline and strongly peraluminous, with K2O/Na2O>1 and A/CNK=1.12–1.54. These rocks are enriched in large-ion lithophile elements (LILEs) and light rare-earth elements (LREEs) [(La/Yb)N =1.13–32.4] and Pb, and are depleted in high field-strength elements (HFSEs). They show similar chondrite-normalized REE patterns, with negative Eu anomalies (Eu/Eu*=0.03–0.46). A wide range of zircon εHf(t) values (−9.6 to −2.6) and varying Hf-isotope crustal model ages (2.1–1.6Ga) are also observed. The geochemical signatures indicate that the leucogranites are S-type granites derived mainly from the anatexis of ancient crustal materials. The ages, geochemistry and tectonics in the Baoshan Block and the Lhasa Terrane are closely comparable, suggesting that the Baoshan Block might represent part of an Early Paleozoic magmatic arc in the Gondwana continental margin facing the proto-Tethyan Ocean. The Pinghe granites of the early phase in the Baoshan Block which are coeval with the Cambrian magmatism (ca. 492Ma) identified in the central and southern Lhasa subterranes can be interpreted as products of the slab break-off associated with the subduction of proto-Tethyan oceanic lithosphere. However, the late leucogranite stocks are analogous to the North Himalayan leucogranites, which formed in a short-lived extensional setting caused by the slab break-off associated with the subduction–collision system. [Copyright &y& Elsevier]

Earth's evolution involves deep, hot rocks rising upward by convection to near-surface environments, as well as the unique scenarios such as the formation and breakup of Gondwana and Pangea. These processes have been well recorded by the widely distributed magmatism. To understand the tectonic evolution and Gondwana assembly, we compiled early Paleozoic zircon U–Pb ages (n = 67), in-situ zircon Hf isotopes (n = 1011), and bulk-rock elemental compositions (n = 293) and Sr–Nd isotopes of magmatic rocks in the Tibetan–Himalayan orogen. Three stages of Paleozoic magmatism were identified here, including early (>490 Ma) to middle (490–470 Ma) to late (<470 Ma) stages, in response to the final assembly of the Gondwana supercontinent. Early-stage magmatic rocks are characterized by highly variable SiO 2 (48.0–80.0 wt%) and MgO (0.02–9.65 wt%) contents with Mg# range from 5.4 to 78, K 2 O/Na 2 O ratios ranging from 0.14 to 2.81, and whole-rock Sr–Nd (87Sr/86Sr(i) (0.7035–0.7340), ε Nd (t) (-9.5–+1.0)) and zircon Hf (ε Hf (t) = –15 to + 8.0) isotopic compositions with significant mantle contributions; they could be generated in an Andean-type arc setting along the active northern continental Gondwana margin. Middle-stage magmas were dominated by fertile continental crustal signatures (SiO 2 > 70 wt%, A/CNK > 1.10, MgO < 2.69 wt%) in a crustal thickening setting. Late-stage magmas also have highly variable Si, Mg and isotopic components, with coeval mantle-derived magmas developing in an extensive setting. Importantly, the widespread presence of early Cambrian to late Ordovician peraluminous high-K calc-alkaline magmatism in the Tibetan–Himalayan orogen indicates that the reworking of ancient continental crustal materials played a key role in reconstructing and stabilizing the final Gondwana assembly. [ABSTRACT FROM AUTHOR]

The Pan-African and Brasiliano orogenies endowed West Gondwanaland with U–Pb 700–500 Ma zircons, which, together with 1200–1000 Ma zircons from Rodinian collisions, are scattered in the Ediacaran–Paleozoic syn- and post-tectonic molassic outflow from the orogens. A more complete (T DM , εHf) isotopic signature in places narrows the search for provenance but exclusive use of the signature is of limited value given the ubiquity of primary and secondary 700–500 Ma and 1200–1000 Ma zircons. To overcome this shortcoming, I link the detrital-zircon signature with paleogeographical indicators of downslope preserved in minor sedimentary structures generated by gravity currents: the cross-dip azimuth in fluvial sediments, flute marks and other vectorial markings in turbidites. The prominent East African-Antarctic Orogen (EA-AO) trends through Africa-Arabia southward through East Africa/Madagascar to Dronning Maud Land in Antarctica. Squire et al. (Squire et al., 2006. Did the Transgondwanan Supermountain trigger the explosive radiation of animals on Earth? Earth and Planetary Science Letters 250, 116–133) postulated > 8000-km-long and > 1000-km-wide Transgondwanan Supermountains (TGSM) atop the EA-AO that resulted in extreme erosion and sedimentation rates; super-fans of quartz sand spread across continental North Africa-Arabia and oceanic crust offshore East Gondwanaland, as seawater 87 Sr/ 86 Sr rose to a maximum. Downslope indicators and the isotopic signature confirm the suggested deposition of the enormous North African-Arabian Super-fan from the Oubanguides Orogen-TGSM (Burke et al., 2003. Africa's petroleum systems: four tectonic ‘Aces’ in the past 600 million years. Geological Society of London Special Publications 207, 21–60), and the Cape Group from the TGSM. Other major provenance → sink relations are the Oubanguides Orogen → Congo Basin and the Damara Orogen and Dom Feliciano Orogens → Nama Basin. Minor and proximal provenance → sink relations are the Tuareg Shield and the Dahomeyides-Nigerian Shield → Volta Basin, and the Paraguay Orogen → Puncoviscana Basin. The voluminous primary sediment deposited during the Ediacaran, Cambrian, and Ordovician was recycled many times up to its present-day appearance in river and beach sand in Africa and in Australia . Compared with 60–0 Ma (~ Cenozoic) collisional Himalaya-Tibet and Mongolian Plateaus and related sediment fans of East Asia, the 700–500 Ma (Ediacaran–Cambrian) collisional continental super-fan in North Africa and Arabia and the deep-sea super-fan off East Gondwanaland are larger in extent and in their impact on seawater 87 Sr/ 86 Sr, probably because West Gondwanaland underwent crustal shortening over a much longer span; furthermore, the ancient morphotectonic regime lasted to the Carboniferous/Permian (~ 300 Ma) merger of Gondwanaland and Laurussia in Pangea, which instituted widespread Pangean-induced subsidence in broad basins that overlapped the planed-off orogens. [ABSTRACT FROM AUTHOR]

New whole-rock geochemical and detrital zircon U–Pb and Lu–Hf data of metasedimentary sequences of the Silvretta Nappe, Orobic Alps, Strona-Ceneri Zone, Gotthard Massif and Venediger Nappe are presented. These units seem to share a common early to middle Paleozoic geological record, which has alternatively been interpreted as the result of intraplate or orogenic processes. Detrital zircon data mainly indicate late Ediacaran to early Ordovician maximum sedimentation ages for the studied sequences, suggesting that they were intimately related to Cadomian and Cenerian orogenic processes along the northwestern Gondwana margin. The common presence of late Ediacaran to Cambrian Cadomian ages associated with variable subchondritic to suprachondritic Lu–Hf compositions points to recycling processes of Cadomian sequences, further supported by geochemical data indicating a relatively low to moderate maturity of sedimentary protoliths. The occurrence of Cenerian arc-related intrusions in Austroalpine and South Alpine basement unit points to an arc/back-arc position in the early Paleozoic Cenerian orogen, except for the Strona-Ceneri Zone, which was likely located closer to the forearc region, as indicated by the presence of high-pressure metamorphism. Younger sequences, such as the Landeck Quartz-phyllite, document post-Cenerian sedimentation, whereas those of the Venediger Nappe more likely record the early stages of Variscan subduction, as indicated by Devonian maximum deposition ages. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fourth member of the Qiasi Group was deposited at ca. 456 – 419 Ma. • Provenance of Ediacaran and early Paleozoic clastic rocks is markedly different. • The Yidun Terrane was linked with East Gondwana in the early Paleozoic. The Yidun Terrane, sandwiched between the Qiangtang and Songpan-Ganze terranes, hosts important information on the tectonic evolution of the eastern Tibetan Plateau. However, its tectonic link with adjacent terranes and East Gondwana remains equivocal. Here, we present U-Pb-Hf isotopes of detrital zircons from the upper Neoproterozoic-lower Paleozoic clastic rocks in the Yidun Terrane. The results show that detrital zircons from the Neoproterozoic rocks are mainly of ca. 821 – 890 Ma, 1714 – 1977 Ma, and 2317 – 2520 Ma, with ε Hf(t) values of each group comparable to coeval magmatic rocks in the nearby South China Block. This suggests that the Yidun Terrane and South China were possibly connected in the late Neoproterozoic, with the latter being the main sedimentary provenance. In contrast, the five Paleozoic samples have markedly different detrital zircon age spectra at ca. 2600 – 2300 Ma, 1100 – 900 Ma, 900 – 740 Ma, and 690 – 480 Ma, which were interpreted to have derived from Pan-African and Grenville-age provinces in the East Gondwana, as well as the South China Block and Songpan-Ganze Terrane. Such a major change on provenance suggests that after prolonged isolation in the Proto-Tethys, the Yidun Terrane began to collide with the East Gondwana in late Ediacaran to early Paleozoic. Integrated with published works, we consider that the Yidun Terrane, along with Songpan-Ganze Terrane and Yangtze Block, was located on the northern margin of East Gondwana during the early Paleozoic. [ABSTRACT FROM AUTHOR]

The pre-Alpine Marmarosh Massif is a tectonically complex unit of the crystalline basement within the Eastern Outer Carpathians. In the eastern (Ukrainian) segment of this massif, two units have been identified—the Bilyi Potok Nappe and the Dilove Nappe. Petrological investigations coupled with zircon U–Pb dating were performed on metavolcanic rocks (porphyroids) and their phyllite host rocks, sampled from three locations within the Dilove Nappe. The geochemical characteristics of the meta-rhyodacite porphyroids revealed a volcanic arc affinity of the protolith, with U–Pb zircon ages of 452.8 ± 1.5 Ma and 461.5 ± 1.6 Ma and zircon saturation temperatures in the range of 823–892 °C. The phyllite host rocks (meta-tuff) yield a U–Pb zircon maximum estimate for the eruption age at 584.7 ± 2.9 Ma. Peak amphibolite-facies metamorphism (M1) was estimated at the pressure of 600–900 MPa with a temperature range of 560–600 °C. Retrogression (M2), possibly related to Alpine nappe stacking and shearing, is assumed to have taken place at 200–250 MPa and 384–222 °C. The volcanic arc is interpreted as an early Caledonian arc that was subsequently accreted to the margin of Baltica during the closure of the easternmost Tornquist Ocean rather than Cenerian (early Paleozoic) orogenic events on the margin of East Gondwana. [ABSTRACT FROM AUTHOR]

The provenance of the upper Cambrian to Upper Ordovician sedimentary rocks of Tasmania and Waratah Bay in southern Victoria provides information about the complex and dynamic tectonic environment present during their deposition. This paper uses U–Pb detrital zircon data to constrain stratigraphic comparisons and tectonic reconstructions of these rock sequences. Multivariate statistics are used to investigate the similarity between the U–Pb ages and quantify the disparity among different samples from various locations. In western and central Tasmania, the Tyennan region supplied most detrital zircons during the late Cambrian and Early Ordovician. The overlying Middle Ordovician Pioneer Sandstone records a switch in provenance with zircons derived from the Mount Read Volcanics (MRV) mixed with zircons similar to those from continental-derived Paleozoic sedimentary rocks deposited throughout east Gondwana. The Middle to Upper Ordovician Gordon Group in western and central Tasmania lacks detrital zircons younger than 1.2 Ga, which indicates a return to a local provenance from Precambrian rocks. In southern Tasmania, the switch to zircons derived from the MRV and east Gondwana-like sources occurred earlier within the Cambrian Deadmans Bay Formation, which is dominated by the east Gondwana Paleozoic zircon age signature. In the East Tasmania Terrane, Ordovician sedimentary rocks from Lefroy have detrital zircon populations dominated by Neoproterozoic and earliest Paleozoic sources similar to the Ordovician sedimentary rocks in the Lachlan Orogen. In southern Victoria, the Bear Gully Chert from Waratah Bay exhibit both Tyennan and distal Gondwana detrital sources. The switching of detrital zircon sources in the west Tasmanian sedimentary sequences implies the docking of Tasmania with mainland Australia during the Cambrian Tyennan Orogeny. The arrival of the distal zircons into these basins occurred at different times in the different areas, reflecting a complex local topography and paleogeography. Paleozoic sedimentary rocks in Tasmanian exhibit multisource detrital U–Pb age signatures that change over time, implying tectonic activity during their deposition. Paleozoic sedimentary rocks in northeastern Tasmania show Gondwana-wide detrital signatures similar to Lachlan Orogen. The Ordovician Bear Gully Chert at Waratah Bay in southern Victoria shows mixed Tasmanian and distal Gondwana detrital populations. The change in detrital zircon signature in western Tasmania suggests that VanDieland docked with the Australian continent during the Cambrian Tyennan Orogeny. [ABSTRACT FROM AUTHOR]

The widespread Tibetan Permo‐Carboniferous glaciogenic diamictites (PCGDs) are conventionally thought to be sourced from Indian Gondwana during glacier transport and deglaciation. However, the Lhasa PCGDs differ in detrital zircon U‐Pb age spectra and εHf(t) values from those in Southern Qiangtang and Tethyan Himalaya. The similarities in εHf(t) values for similar‐age detrital zircons, the development of glacier transport pathways, and the large volumes of the Tibetan PCGDs indicate an Australian source for the Lhasa PCDGs, and an Indian source for the Southern Qiangtang and Tethyan Himalayan PCDGs. We conclude that the Southern Qiangtang and Tethyan Himalayan are paleographically linked to northern India, whereas Lhasa is positioned adjacent to NW Australia during the Paleozoic. Magmatic and metamorphic records further indicate that eastern Lhasa (E90°–E95°) represents the outboard extension of events recorded in northern Central Australia, whereas western Lhasa (E80°–E90°) was located outboard of the West Australian Craton. Plain Language Summary: Precisely understanding the paleogeography of the Lhasa Terrane in southern Tibet is crucial to reconstruct the opening and drifting histories of the Neo‐Tethys that controls on the evolution of the India‐Asia collision zone. The paleogeography of the Lhasa Terrane has been variously proposed to originate from northern India, northwest Australia, and the northern extent of the East African Orogen. Resolving this paleogeographic puzzle requires solid lines of evidence and a full understanding of the data. A combination of new detrital zircon U‐Pb age and Hf isotope data of the Tibetan Permo‐Carboniferous glaciogenic diamictites constrains the paleogeography of the Lhasa Terrane to a position adjacent to NW Australia. Magmatic and metamorphic records further refine that the eastern Lhasa (E90°–E95°) represents the outboard extension of events recorded in northern Central Australia, whereas the western Lhasa (E80°–E90°) was located outboard of the West Australian Craton. Our results show that a combination of provenance analysis (including magmatic history, isotopic data, and sediment transport pathway) of the widespread late Paleozoic diamictites in Gondwana, as well as magmatic and metamorphic records, can allow precise paleogeographic reconstruction of the longitudinal disposition of blocks along the northern Gondwana margin. Key Points: Lhasa Permo‐Carboniferous glaciogenic diamictites (PCGDs) differ in detrital zircon U‐Pb age and εHf(t) from those in S. Qiangtang and Tethyan HimalayaLhasa PCGDs come from Australian Gondwana, whereas the S. Qiangtang and Tethyan Himalayan PCGDs from Indian GondwanaE. Lhasa represents the outboard extension of N. Central Australia, whereas W. Lhasa was located outboard of the West Australian Craton [ABSTRACT FROM AUTHOR]

[Display omitted] • Ordovician to Triassic maximum depositional ages are determined from Sibumasu in NW Thailand. • 1200–900 Ma, 650–500 Ma and 2500–2460 Ma populations are present in all 8 NW Thai detrital samples. • Hf signatures change provenance from Gondwana in Ordovician-Permian to Indosinian in Triassic. • Our comparison with published detrital data is inconsistent with composite Sibumasu models. The evolution of the Sibumasu Terrane forms a principal component in the history of the Tethys Oceans with the northward movement of Gondwana-derived terranes creating the Asian continent that we recognise today. While there are various reconstructions for the palaeoposition of the Sibumasu Terrane during the Proterozoic and Paleozoic, the terrane is commonly placed outboard of the northwest Australian margin in the Gondwanan supercontinent. In this study, U–Pb and Lu–Hf isotopic information has been collected from detrital zircons of Paleozoic and Mesozoic sedimentary rocks obtained from the Sibumasu Terrane in northwest Thailand. This is the first zircon Hf analysis from these sedimentary sequences. These new data are statistically and visually compared with data from Sibumasu, Indochina, Sukhothai, West Burma and Tethyan Himalayas terranes along with the terranes of China, India and Western Australia. Our detrital data are consistent with other published data indicating consistent sources across the Sibumasu Terrane, inconsistent with composite terrane reconstructions. However, temporally, the detrital ages change from older Paleozoic sedimentary sequences (sourcing zircons from Neoproterozoic and older "Gondwanan" sources) to latest Permian-Triassic sedimentary units with Indosinian zircon sources. This change is consistently reflected in this study through both the U–Pb ages and Hf signatures with Proterozoic age peaks characteristic of Gondwana and younger Indosinian sources being consistent with granitoids emplaced through the amalgamation of Thailand. The temporal changes in the isotopic systems reflect the movement of the Sibumasu Terrane from the northwest Australian margin of Gondwana to its collision with the terranes of present-day Asia. [ABSTRACT FROM AUTHOR]

• Part of uppermost basement in the West Kunlun Orogen is early Paleozoic. • Arc-related magmatism in the West Kunlun Orogen continuous during early Paleozoic. • Subduction retreating during Neoproterozoic and advancing during early Paleozoic. • Advancing subduction at 540–420 Ma likely responsible for closure of Proto-Tethys Ocean. The West Kunlun Orogenic Belt (WKOB) is a key area for evaluating the evolution of the Proto-Tethys Ocean. To constrain this history, we present geochemical and zircon U-Pb geochronological data from a suite of metasedimentary rocks within this orogenic belt. Detrital zircons ages are clustered between 1000 and 400 Ma, with major peaks at ca. 510 Ma and 460 Ma, and minor peaks at ca. 840 Ma and 650 Ma. The age groups younger than 1000 Ma broadly overlap magmatic activity at ca. 540–420 Ma and minor magmatism at 920–540 Ma in the WKOB. The age data also reveal Early Paleozoic metamorphic basement rocks in the WKOB that were probably sourced from Kunlun terranes and blocks of Gondwanan affinity rather than the Tarim Craton. Compiled geochemical data suggest a protracted subduction setting in the WKOB in the Early Paleozoic. εHf(t) values show increasing trends at 900–740 Ma and 740–600 Ma and a distinct decreasing trend at 540–420 Ma, consistent with retreating subduction during the Neoproterozoic and advancing subduction in the Early Paleozoic. The retreating-advancing subduction cycle in the WKOB was possibly related to the opening and closure of the Proto-Tethys Ocean along the margin of Gondwana. [ABSTRACT FROM AUTHOR]