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The Eastern Pontides orogenic belt (EPOB) represents a significant segment of the Alpine-Himalayan orogenic belt that evolved from the Paleozoic to Cenozoic periods. Here we report new zircon U-Pb ages, together with Lu-Hf isotopes, and whole-rock geochemical and Sr-Nd isotopic analyses of plutonic rocks from EPOB, northeastern Turkey. Our aim is to interpret magmatic evolution in which the granitoids formed. Zircon U-Pb dating of six samples yielded crystallization ages of ∼134, ∼82, ∼39 Ma, respectively. They show a wide range of 87Sr/86Sr(i) (0.703 9–0.710 9), and εNd(t) values varying from −9 to +4.6, yielding model ages (TDM) from 520 to 1 623 Ma, suggesting a heterogeneous magma source. Dated zircons show exlusively positive εHf(t) values (+12.4 to +1.4), yielding model ages (TDM) from 352 to 1 059 Ma, implying that they are most likely derived from a juvenile lower crust rather than the mature continental crust. In this study, we suggested that the northward subduction of the Neo-Tethyan oceanic slab began from the Early Cretaceous and resulted in the Late Cretaceous magmatism. Moreover, the Middle Eocene magmatism in the EPOB was related to the collision of the Anatolide Taurid Platform (ATP) with the Pontides. [ABSTRACT FROM AUTHOR]

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: To constrain the paleoposition of the Tengchong block within Gondwana during the Early Paleozoic, we performed in-situ U–Pb and Hf isotope analyses on detrital zircons from Carboniferous strata in the Tengchong block. The age distributions yield dominant Neoarchean (~2.5Ga), Mesoproterozoic (1.7–1.4Ga), Grenvillian (~0.95Ga), and Pan-African (0.65–0.5Ga) age groups. Hf isotope compositions of Mesoproterozoic, Grenvillian, and Pan-African zircon age groups exhibit wide range of ε Hf(t) suggesting their diverse sources. The oldest Hf model ages indicate that the source magma included reworked Eoarchean (3.8–3.7Ga) crustal materials. The remarkable resemblance of zircon age spectra and Hf isotopes from the Tengchong block with those from Tethyan Himalayan, western Qiangtang and Indochina suggests that the Tengchong block was located along the Indian margin of Gondwana during the Early Paleozoic. In Grenvillian and Pan-African, crustal growth for the source areas was insignificant. [Copyright &y& Elsevier]

This article presents U–Th–Pb and Lu–Hf detrital zircon isotope data, as well as whole-rock Sm–Nd isotope data on metasedimentary rocks from the eastern part of the Tukuringra Terrane. Our analyses show that the zircons in metasedimentary rocks are mostly early Mesozoic. The Early Mesozoic, Early Paleozoic and Neoproterozoic zircons are predominant and Early Precambrian zircons are almost absent in these rocks. The age of the youngest zircon population places a lower age limit of sedimentation at 204 Ma for the Tungala Formation (Upper Triassic, Rhaetian), at 181 Ma for the Dugda Formation (Lower Jurassic, Toarcian), and at 189 Ma for the Tangomen Formation (Lower Jurassic, Pliensbachian). Practically all Mesozoic, Paleozoic, and Neoproterozoic zircons are characterized by Neo- and Mesoproterozoic Hf-model ages (tHf(DM)) = 1.41–0.46 Ga, tHf(C) = 1.55–0.49) and Mesoproterozoic Nd-model ages (tNd(DM) = 1.25–1.10 Ga, tNd(C) = 1.31–1.14). These results indicate that the sedimentary rocks were mainly sourced from the Amur continental superterrane, but not from the southern framing of the North Asian Craton. [ABSTRACT FROM AUTHOR]

Precise timing of granitoids and constraints of their magma sources are critical to understanding the subduction–collision tectonic evolution of the Altun orogenic belt (AOB), a vital part of the Qinghai-Tibet plateau in northwestern China. We provide in-situ zircon U–Pb age, Hf isotopic composition and whole-rock geochemistry of the Yusupualeke granitic pluton in the South Altun orogenic belt (SAOB), an integral unit of the AOB, to determine the tectono-magmatic evolution of the SAOB at early Palaeozoic. The Yusupualeke granitic pluton comprises the medium-coarse grained porphyritic monzogranite and medium-fine grained granodiorite. The monzogranite sample yielded a weighted mean 206Pb/238U age of 476.8 ± 3.6 Ma (MSWD = 0.59), while the granodiorite yielded a weighted mean 206Pb/238U age of 453.2 ± 4.7 Ma (MSWD = 0.013). Zircon U–Pb ages suggest that the subduction–collision process of the SAOB remained from the middle stage of the early Palaeozoic to the end. Both of the studied granitoids belong to metaluminous to weakly peraluminous series and show typical I-type granite characteristics with depletions in Ba, Nb, Sr, P, and Ti, and enrichments in light rare earth elements (LREEs), Rb, Th, K, and slightly negative Eu anomalies. Based on the geochronological data and regional geological background, we believe that the porphyritic monzogranites were formed during the northward subduction process of the South Altun ocean (SAO), while the granodiorites were formed during the tectonic regime transition stage. Besides, combing the previous research achievements with our newly obtained data, we put forward a new division and geodynamic model of the early Palaeozoic tectono-magmatic evolution for the South Altun orogenic belt. [ABSTRACT FROM AUTHOR]

Garnet peridotite, garnet pyroxenite, mafic granulite and dominant felsic granulite constitute a high-pressure/high-temperature (HP/HT) metamorphic terrane in the south Altyn Tagh, North Tibet (China). Garnet peridotite and associated garnet pyroxenite occur as slices or lenses within high pressure felsic granulite. Previous studies indicate that garnet peridotite experienced the peak HP/HT metamorphism, followed by a medium pressure granulite-facies overprint. However, the origin of the garnet peridotite and associated garnet pyroxenite remains controversial. In this contribution, we present new zircon U–Pb and Hf isotopic data and whole-rock major, trace element and Sr–Nd isotopic data for the representative garnet peridotites and associated garnet pyroxenites. SHRIMP U–Pb dating on the inherited (magmatic) zircons from the garnet peridotites gave an U–Pb age of ca. 780 Ma, which is interpreted as the age of the ultramafic magma crystallization. The metamorphic zircons yield an age of ca. 500 Ma, which is consistent with the Sm–Nd isochron age of 493 ± 24 Ma for whole rock, garnet and clinoproxene from a garnet pyroxenite, representing the timing of peak metamorphism. The Baishiwake garnet peridotites and garnet pyroxenites show relatively high contents in Fe 2 O 3 , TiO 2 , P 2 O 5 , Nb, Zr, and Y, but significantly low MgO, Cr, A1 2 O 3 and Ni contents. They possess enriched LREE, nearly flat HREE, slightly positive Eu anomaly and weak negative anomalies in Nb and Ti. The relatively high 87 Sr/ 86 Sr ratios (0.707–0.710) and low 143 Nd/ 144 Nd ratios (0.5123–0.5124) imply a possible crust contamination prior to HP metamorphism. Integrating these data together with previous studies, we suggest that the Bashiwake garnet peridotites and associated garnet pyroxenites were derived from mantle-derived magmas which intruded into the continental crust during the Neoproterozoic and then experienced a common HP/HT metamorphism with felsic crustal rocks in the Early Paleozoic (ca. 500 Ma). [ABSTRACT FROM AUTHOR]

Abstract: To constrain the paleoposition of Indochina within Gondwana during the Early Paleozoic, we performed in-situ U–Pb and Hf isotope analyses on detrital zircons from three river sediment samples in the Truong Son Belt of the Indochina block. The age distributions yield dominant Neoarchean (~2.5Ga), Mesoproterozoic (1.7–1.4Ga), Grenvillian (~0.95Ga), and Pan-African (0.65–0.5Ga) age groups and minor Paleo- to Meso-archean zircons. Hf isotope compositions of zircons for each age group exhibit large ranges of εHf(T), suggesting that the zircon host rocks have diverse sources. The oldest Hf model ages for zircons of Neoarchean, Grenvillian, and Pan-African age group yield ~3.7Ga or older, while those of Mesoproterozoic age group show ~3.3Ga. The remarkable similarity of age distribution and Hf isotope compositions among detrital zircons of Indochina and those of Tethyan Himalaya, western Cathaysia, and Qiangtang suggests that Indochina was located outboard of Qiangtang and south of South China in the Indian margin of Gondwana during the Early Paleozoic. Our results are consistent with the paleontological correlations of east Gondwana margin during the Early Paleozoic. [Copyright &y& Elsevier]

Abstract This study presents new zircon U-Pb geochronological, whole-rock geochemical, and zircon Hf isotopic data along with regional geological observations for five late Paleozoic granitic plutons within the Xing'an Block of northeastern China. These data provide insights into the petrogenesis of these granitoids and the late Paleozoic tectonic evolution of the region. The geochronological and geochemical data indicate that the intrusions were emplaced during two separate periods, with the resulting granites having distinct geochemical features. The early Late Carboniferous (321–310 Ma) granitic Lizishan (LZS), Xiaonangou (XNG), and Dabeigou (DBG) plutons have high Sr/Y values (33.15–126.73), with low concentrations of Y and heavy rare earth elements (HREE), indicating adakitic affinities. However, the XNG granodiorites contain higher concentrations of MgO, Cr, and Ni, and have higher Mg# values (57–59) than the other plutons. The latest Carboniferous–Early Permian (301–296 Ma) granitic Weilegesi (WLGS) and Wuyi (WY) plutons are high-K calc-alkaline, with low Sr/Y ratios (0.18–24.15), and show petrological and geochemical characteristics of I-type granites. In addition, the magmatic zircon crystals within these plutons yield positive ε Hf (t) values (+4.1 to +12.9) and juvenile two-stage model (T DM2) ages (1056–499 Ma). The timing of emplacement and geochemical and isotopic compositions of the LZS and DBG granitoids are indicative of derivation from magmas generated by the partial melting of thickened lower crustal material, whereas the XNG granitoids were most likely formed from magmas generated by the partial melting of delaminated lower crustal material that subsequently interacted with mantle material during ascent. The latest Carboniferous–Early Permian low-Sr/Y granitoids may have formed from magmas generated by the partial melting of a dominantly juvenile amphibolite-facies crustal source under relatively low-pressure conditions, with these magmas subsequently undergoing variable degrees of fractional crystallization. Combining these new data with the results of previous research indicates that the terminal collision between the Xing'an and Songliao blocks occurred between the late Early and early Late Carboniferous, and the voluminous Late Carboniferous to Early Permian granitoids in the Xing'an Block are most likely related to post-collisional delamination. Graphical abstract Unlabelled Image Highlights • Late Paleozoic high- and low-Sr/Y granitoids are identified in the Xing'an Block. • The collision between the Xing'an and Songliao blocks occurred during ~330–310 Ma. • Late Carboniferous–Early Permian magmatisms formed by post-collisional delamination. [ABSTRACT FROM AUTHOR]

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]

[Display omitted] • Early Paleozoic carbonatite with zircon U-Th-Pb age of ∼435 Ma was identified. • The Early Paleozoic carbonatite originated from a mantle different from the Mesoproterozoic carbonatite. • The Early Paleozoic carbonatite might contribute to REE mobilization and re-enrichment. The Bayan Obo deposit in China hosts the world's largest rare earth element (REE) resource. Age dating results for Bayan Obo range across approximately one billion years (from ∼1.4 to 0.3 Ga), with three age groups (∼1.3 Ga, ∼0.45–0.40 Ga, and 0.28–0.26 Ga). Carbonatite dated to around 1.3 Ga and granitoids to approximately 270 Ma have been identified. The Early Paleozoic vein-type mineralization is widespread in the deposit. However, magmatic activity related to the highest age peak at ∼0.4 Ga has not well been identified in the deposit, complicating the interpretation of the ore genesis. In this study, we report a zircon 232Th-208Pb age of 435.2 ± 4.6 Ma (MSWD = 1.9, N = 26) from carbonatite in Bayan Obo. The zircon morphology, characterized by bipyramidal crystal forms, low U concentrations (mostly < 1 ppm), high Th/U ratio, and carbonatite-like oxygen isotopes (5.92 ± 0.31 ‰), demonstrates that the zircon crystallized from carbonatitic magmas, thus their ages represent the timing of magmatic activity. Although remelting of the Mesoproterozoic carbonatite during Paleozoic carbonatite has been previously documented, the newly identified Early Paleozoic carbonatite derives from a different mantle source, as indicated by their more radiogenic Hf isotope compositions. This suggests that the Bayan Obo deposit experienced multiple carbonatitic activities. The Early Paleozoic carbonatitic activity may have facilitated element mobilization and mineral recrystallization, improving the exploitable levels of the world's largest REE deposit. [ABSTRACT FROM AUTHOR]

The late‐stage union of Pangea was associated with the convergence of Siberia with Laurussia, but the exact timing remains unclear. The orogenic duration of the Kazakhstan block can provide geochronological constraints as it connects Siberia, Baltica, and Tarim. Zircon petrochronology offers a reliable approach for ascertaining the lifespan of an ancient orogen. In this study, we explore three phases of magmatism recorded in detrital zircons from late Paleozoic and Mesozoic sandstone‐siltstones in Western Tianshan, that is, 400–470 Ma, 320–380 Ma, and 280–320 Ma. Based on their age‐propagated Hf isotopes, melt SiO2 contents, and crustal thicknesses, our findings suggest that the southern limb of Kazakhstan underwent the early Paleozoic amalgamation of microcontinents with arcs, the late Paleozoic maturation of an Andean‐like continental arc, and the late Carboniferous collision of Kazakhstan with the Junggar oceanic basin and the Tarim craton. Such characteristics manifest the long‐term orogenic progression of Kazakhstan. Combining published timelines and paleolatitudes of major orogens and blocks, we propose that the Kazakhstan block welded northeastern Pangea along with the cessation of these orogenic activities around it. Consequently, by docking Kazakhstan with surrounding cratons, the fundamental configuration of Pangea could have been established in the late Carboniferous. Plain Language Summary: Pangea was suggested to have assembled at ca. 250 Ma upon paleogeographic reconstructions. However, the assembling time remains a matter of debate due to low‐quality Permo‐Carboniferous paleomagnetic data on the northeast of Pangea; thus, other geochronological records need to be determined. Here, we employ the method of zircon petrochronology to trace the orogenic processes of Kazakhstan because it serves as a pivot in welding peripheral Siberia, Baltica, and Tarim blocks. Our results demonstrate that episodic variations in melt compositions, crustal thicknesses, and Hf isotopes reveal the long‐lived orogenic progression of the southern limb of Kazakhstan and constrain its incorporation into Pangea to the late Carboniferous. Such an event was almost contemporaneous with the assembly of Baltica and Siberia with the northern limb of Kazakhstan but occurred slightly later than the collision of Laurussia with Gondwana. As such, the fundamental configuration of Pangea could have been established in the late Carboniferous rather than the Permian, as previous paleogeographic reconstructions postulated. Key Points: Detrital zircons in Western Tianshan record three phases of Paleozoic magmatismZircon petrochronology can trace orogenic processes of the southern limb of KazakhstanDocking Kazakhstan with surrounding cratons in the late Carboniferous marked the major assembly of the northeastern Pangea [ABSTRACT FROM AUTHOR]

Abstract: Detrital zircon grains from Lower Paleozoic sedimentary rocks in the Yucatan Peninsula have an age distribution characterized by major probability peaks at ~1.0, ~1.2, and ~1.5Ga (Martens et al., 2010). Here, we present new Lu–Hf data (MC–ICPMS) paired with U–Pb ages (ID-TIMS) for additional zircon grains from the same rocks. This analytical approach yields precise information about the time and geochemical environment of zircon growth, which in turn helps to distinguish between different crustal source regions that just happen to host zircon populations of similar age. In addition, single zircon grains from granitoids that intruded the sedimentary rocks were dated by U–Pb laser ablation MC–ICPMS and ID-TIMS, and their Hf-isotope compositions were determined by solution MC–ICPMS. The zircon data are complemented by Sm–Nd analyses of the sedimentary and igneous whole rocks. The Yucatan Peninsula, which forms part of the Maya block of Central America, includes lower Paleozoic rocks in the Maya Mountains of Belize. The pre-Mesozoic geologic history of the Maya block is related to the evolution of the mid-Proterozoic basement in Mexico (Oaxaquia), other Paleozoic peri-Gondwanan terranes, and the Pan-African–Brasiliano type basement of Florida. The initial 176Hf/177Hf values of ~1.0Ga detrital zircon grains lie on a crustal evolution trajectory similar to that defined by older, ~1.2 to ~1.5Ga grains. This trajectory is consistent with those that would be produced by crustal reservoirs that separated from the depleted mantle between 1.70 and 2.05Ga. However, some grains have significantly less radiogenic 176Hf/177Hf(t), indicating influence from even older cratonic crust. Zircon grains from granitoids that intruded the Early Paleozoic sedimentary rocks of the Yucatan Peninsula yielded Late Silurian to Early Devonian (~415–400Ma) crystallization ages. More radiogenic Hf isotope ratios indicate anatexis of a crustal reservoir that is distinct from that of the Early Paleozoic sedimentary rocks. The Sm–Nd systematics of whole rock samples further support the results from the Hf isotopes in zircon grains. The data suggest a more continental provenance for the sedimentary rocks from Yucatan as compared to typical ca. 1.3 to 1.0Ga outcrops in southern and central Mexico. The results indicate that sediments were shed either from mid-Proterozoic complexes of NW Amazonia or from similar continental sequences that were thrust over Oaxaquia during the Grenville orogeny and subsequently eroded in the early Paleozoic. Integrating the data into a new model for early Paleozoic times, the southern Maya block is inferred to have formed during the opening of the Rheic Ocean along the western margin of Amazonia adjacent to Oaxaquia. The paucity of Ediacaran (Pan African–Brasiliano) signatures implies that before the Silurian, the southern Maya block evolved geographically separated from NW Yucatan and Florida, where Pan African–Brasiliano crystalline rocks have been reported. [Copyright &y& Elsevier]

This work presents the whole-rock elemental geochemistry and Sr − Nd isotopes and zircon Hf − O isotopes for dikes from Tagaolemiao and Tuilamamiao, the southern margin of the southeast Central Asian Orogenic Belt (SE CAOB), to explore their origin and dynamic setting. Zircon U − Pb dating reveals that the Tagaolemiao dikes emplaced at ca. 242 Ma and the Tuilamamiao dikes emplaced at ca. 250 Ma, which postdated the Late Permian magmatic lull and convergent events in the SE CAOB. Dikes from the two areas are I-type rhyolitic rocks and exhibit high SiO 2 , low MgO, and low Cr, Co, and Ni contents. The Tagaolemiao dikes have depleted zircon Hf (ε Hf (t) = +3.75 to +9.82), whole-rock Sr − Nd (I Sr (t) = 0.704340–0.704855; ε Nd (t) = +1.3 to +2.1) isotopic composition and variable zircon δ18O values (4.88–7.29‰), and were derived from the mixing melts of the juvenile crust and depleted mantle. In contrast, the dikes from Tuilamamiao show negative zircon ε Hf (t) (−2.33 to −10.85) and whole-rock ε Nd (t) (−6.7 to −15.5) values, low I Sr (t) (0.706640–0.708208) and high δ18O (6.38–7.61‰) values, which originated from the partial melting of the old continental lower crust. The Triassic dyke swarms from this work indicate the SE CAOB switched into an intra-continental extension tectonic setting after the Paleozoic long-term accretion-convergence. • Early-Middle dikes were derived from the thickened lower crust. • Triassic dyke swarms reveal an intra-continental extension setting. • Vigorous mantle perturbation is important to the Triassic tectonics in the SE CAOB. [ABSTRACT FROM AUTHOR]

The Polish Lowlands, located southwest of the Teisseyre-Tornquist Zone, within Trans-European Suture Zone, were affected by bimodal, but dominantly rhyolitic, magmatism during the Late Paleozoic. Thanks to the inherited zircon they contain, these rhyolitic rocks provide a direct source of information about the pre-Permian rocks underlying the Polish Lowland. This paper presents zircon U-Pb geochronology and Hf and O isotopic results from five drill core samples representing four rhyolites and one granite. Based on the ratio of inherited vs. autocrystic zircon, the rhyolites can be divided into two groups: northern rhyolites, where autocrystic zircon is more abundant and southern rhyolites, where inherited zircon dominates. We suggest that the magma sources and the processes responsible for generating high silica magmas differ between the northern and southern rhyolites. Isotopically distinct sources were available during formation of northern rhyolites, as the Hf and O isotopes in magmatic zircon differ between the two analysed localities of northern rhyolites. A mixing between magmas formed from Baltica-derived mudstone-siltstone sediments and Avalonian basement or mantle can explain the diversity between the zircon compositions from the northern localities Daszewo and Wysoka Kamieńska. Conversely, the southern rhyolites from our two localities contain zircon with similar compositions, and these units can be further correlated with results from the North East German Basin, suggesting uniform source rocks over this larger region. Based on the ages of inherited zircon and the isotopic composition of magmatic ones, we suggest that the dominant source of the southern rhyolites is Variscan foreland sediments mixed with Baltica/Avalonia-derived sediments. [ABSTRACT FROM AUTHOR]

Hf-isotope data of >1100 detrital zircon grains from the Palaeozoic, south-central Andean Gondwana margin record the complete crustal evolution of South America, which was the predominant source. The oldest grains, with crustal residence ages of 3.8-4.0 Ga, are consistent with complete recycling of existing continental crust around 4 Ga. We confirm three major Archaean, Palaeoproterozoic (Transamazonian) and late Mesoproterozoic to early Neoproterozoic crust-addition phases as well as six igneous phases during Proterozoic to Palaeozoic time involving mixing of juvenile and crustally reworked material. A late Mesoproterozoic to early Neoproterozoic, Grenville-age igneous belt can be postulated along the palaeo-margin of South America. This belt was the basement for later magmatic arcs and accreted allochthonous microcontinents as recorded by similar crustal residence ages. Crustal reworking likely dominated over juvenile addition during the Palaeozoic era, and Proterozoic and Archaean zircon was mainly crustally reworked from the eroding, thickened Ordovician Famatinian arc. [ABSTRACT FROM AUTHOR]

It is broadly accepted by researchers that the North China Craton (NCC) was linked with the Pangea supercontinent by the Central Asian Orogenic Belt (CAOB) resulted from the final closure of the Paleo Asian Ocean (PAO), but when and how still be controversial, such as one-sided subduction and continental collision, or double-sided subduction and soft collision, the ocean basin closed in the Devonian or Late Permian and so on. We conducted zircon U-Pb-Hf isotopes analyses of 5 Paleozoic sedimentary samples which collected along the Bainaimiao area, locates at the northern margin of the NCC, and compared their zircon U-Pb isotopic ages and εHf(t) values with those former published data in the north orogenic belt (NOB) and the south orogenic belt (SOB) to trace provenance differences between the NOB and SOB. Our sedimentary samples have several prominent age peaks at circa 270 Ma, 460 Ma, 1350 Ma, 1750 Ma and 2500 Ma, respectively, and cover different εHf(t) values in different age peaks, which have shown complex tectonic evolution of the NCC and the Bainaimiao arc belt. In our comparison, the Neo-Proterozoic zircons are common seen in the NOB data, but rare in the SOB data, and Devonian zircons from the NOB have mostly shown positive εHf(t) values while most of which from the SOB are negative, which mean that the NOB magmatism events in Paleozoic period had formed juvenile crust but the SOB magmatism events in temporary period result from reworking of older crust according to detrital zircon ages and relevant εHf(t) values. In addition, trace elements analysis of the detrital zircons, such as U, Hf, Y, Th, Yb and so on, was also used to help distinguishing the tectonic setting of the formation of these zircons. Our data shows that most Paleozoic zircons have lower Y concentration and higher U/Yb (>0.1) ratios, which can be inferred that these zircons may crystalized in continental magmatic setting, which supports the viewpoint that the oceanic crust of the PAO subducted beneath the NCC in the Paleozoic to form and transform the Bainaimiao arc belt. In summary, we use detrital zircons geochronology and trace elements analyses to outline Paleozoic magmatic events occurred in the northern margin of the NCC, to discuss the attribute of the Bainaimiao arc belt, and imply that there was no material exchange between the NOB and the SOB in the Paleozoic, namely, the PAO oceanic basin still remained open until the Permian, and the eastern segment of the CAOB may finally formed after the Paleozoic. [ABSTRACT FROM AUTHOR]

Considerable controversy concerns the consumption and closure processes of the North and South Altyn Oceans resulting in the formation of the North Altyn Tagh subduction-accretion belt and the South Altyn Tagh subduction-collision belt in the Altyn Tagh orogen in southeastern Tarim. This study focused on U–Pb ages and Hf isotopes of detrital zircons from early Paleozoic sedimentary rocks in the Central Altyn Tagh terrane. Our dating results revealed that the studied sedimentary rocks were deposited at ca. 467–429 Ma. The predominant early Paleozoic detrital zircons demonstrate negative εHf(t) values, highlighting their derivation from the coeval intermediate-felsic magmatic rocks sourced from ancient supracrustal materials with enriched isotopes. These inferred, enriched intermediate-felsic magmatic rocks were probably generated in different consumption and closure processes of the North and South Altyn Oceans, based on geochronology and geochemistry of the early-middle Paleozoic intermediate-felsic magmatic rocks in the Altyn Tagh orogen. A number of ca. 520–490 Ma detrital zircons were primarily derived from the coeval, enriched intermediate-felsic magmatic rocks in the local Central Altyn Tagh terrane and the adjacent North Altyn Tagh subduction-accretion belt associated with the advancing subduction of the North Altyn Ocean. The ca. 490–470 Ma detrital zircons are most prominent and suggest a derivation from the coeval, enriched magmatic rocks subject to the rollback of the North Altyn Ocean. These inferred magmatic rocks might have once existed in the region but have been intensely exhumed to be source material for the studied sedimentary rocks. A few ca. 450 Ma detrital zircons indicate a provenance from the North Altyn Tagh subduction-accretion belt during collision after the final closure of the North Altyn Ocean. In contrast, some ca. 470–460 Ma detrital zircons were probably derived from the coeval intermediate- to felsic-magmatic rocks in the Central Altyn Tagh terrane during the exhumation stage of the deep continental collision after the final closure of the South Altyn Ocean. Combination of provenance study and magmatic record provides potential to establish complicated orogenic evolution. [ABSTRACT FROM AUTHOR]

The origin and tectonic evolution of the early Paleozoic arc terranes abutting the northern margin of the North China Craton (NCC) are widely debated. This paper presents detrital zircon U-Pb and Hf isotopic data of early Paleozoic strata in the Zhangjiatun arc terrane of central Jilin Province, northeast (NE) China, and compares them with the Bainaimiao and Jiangyu arc terranes abutting the northern margin of the NCC. Detrital zircons from early Paleozoic strata in three arc terranes exhibit comparable age groupings of 539-430, 1250-577, and 2800-1600 Ma. The Paleoproterozoic to Neoarchean ages and Hf isotopic composition of the detrital zircons imply the existence of the Precambrian fragments beneath the arc terranes. Given the evidences from geology, igneous rocks, and detrital zircons, we proposed that the early Paleozoic arc terranes abutting the northern margin of the NCC are a united arc terrane including the exotic Precambrian fragments, and these fragments shared a common evolutionary history from Neoproterozoic to early-middle Paleozoic. [ABSTRACT FROM AUTHOR]

Abstract: The North Tianshan orogenic belt in Kyrgyzstan consists predominantly of Neoproterozoic to early Paleozoic assemblages and tectonically interlayered older Precambrian crystalline complexes and formed during early Paleozoic accretionary and collisional events. One of the oldest continental fragments of late Mesoproterozoic (Grenvillian) age occurs within the southern part of the Kyrgyz North Tianshan. Using SHRIMP zircon ages, we document two magmatic events at ~1.1 and ~1.3Ga. The younger event is characterized by voluminous granitoid magmatism between 1150 and 1050Ma and is associated with deformation and metamorphism. The older event is documented by ~1.3Ga felsic volcanism of uncertain tectonic significance and may reflect a rifting episode. Geochemical signatures as well as Nd and Hf isotopes of the Mesoproterozoic granitoids indicate melting of still older continental crust with model ages of ca 1.2 to 2.4Ga. The Mesoproterozoic assemblages are intruded by Paleozoic diorites and granitoids, and Nd and Hf isotopic systematics suggest that the diorites are derived from melts that are mixtures of the above Mesoproterozoic basement and mantle-derived material; their source is thus distinct from that of the Mesoproterozoic rocks. Emplacement of these plutons into the Precambrian rocks occurred between 461 and 441Ma. This is much younger than previously assumed and indicates that small plutons and large batholiths in North Tianshan were emplaced virtually synchronously in the late Ordovician to early Silurian. The Mesoproterozoic rocks in the North Tianshan may be remnants of a once larger continental domain, whose fragments are preserved in adjacent blocks of the Central Asian Orogenic Belt. Comparison with broadly coeval terranes in the Kokchetav area of northern Kazakhstan, the Chinese Central Tianshan and the Tarim craton point to some similarities and suggests that these may represent fragments of a single Mesoproterozoic continent characterized by a major orogenic event at ~1.1Ga, known as the Tarimian orogeny. [Copyright &y& Elsevier]

The Song Ma zone in NW Vietnam bears important tectonic implications as a potential subduction corridor between the Indochina and South China blocks. On the basis of U-Pb ages, the Hf isotopic characteristics of zircons and the geochemical composition of granitoids, a two-stage magmatic evolution process of the Song Ma zone at ~290-260 and ~245-230 Ma can be proposed. Isotopic analyses indicate magmatic contributions from Neoproterozoic oceanic island basalt, Proterozoic continental crust, and depleted mantle or juvenile lithosphere. By combining geochronological and geochemical data from the granitoid rocks, we suggest that the staged magmatic processes of Song Ma zone may be related to a long-lasting period of ocean subduction (ca. 290-260 Ma) and subsequent syn-/post-collisional evolution (ca. 245-230 Ma). [ABSTRACT FROM AUTHOR]

Voluminous rhyolitic lavas and ignimbrites (c. 34 000 km3) were formed in the NE German Basin in a post-collisional setting at c. 295 Ma. Trace elements, &varepsilon;Hf and δ18O have been measured in dated magmatic and inherited rhyolitic zircons from three drill cores across the basin. Magmatic zircons crystallized in two stages: the first stage in less differentiated and isotopically heterogeneous magmas and the second stage in more differentiated and isotopically homogeneous magmas. The first and second stages can be related to the crystallization of zircons within a heterogeneous pluton and in an evolved, silicic magma that was later erupted. Some zircons crystallized entirely during the evolved magma stage and provide good resolution for identifying and characterizing processes happening shortly before eruption. The isotopic compositions of the magmatic zircons constrain the proportions of juvenile and reworked materials involved in the formation of voluminous silicic magmas in a post-collisional tectonic setting. The advantage of studying the volcanic rocks from the NE German Basin is that their petrogenesis involved a relatively simple, two-source interaction during magma production, which permits quantitative estimation of the amount of each source component. AFC modelling shows that the first stage zircons crystallized from magmas containing 5–80% of the juvenile component, whereas the final rhyolitic magmas contained 30–40% of this material. The inherited zircons have Hf model ages of 1·9–2·2 Ga, suggesting that much of the local basement was initially derived from the mantle at that time and that it was subsequently reworked at around 1·5 Ga. Similar model ages are a feature of Baltica-derived sediments and the implication is that such sediments underlie large areas of the NE German Basin. The lack of any record of Avalonian basement in the NE German Basin may indicate that both the sedimentary cover and the underlying basement are part of Baltica. [ABSTRACT FROM AUTHOR]

Abstract: We have carried out zircon U-Pb SHRIMP dating and Hf isotope determinations on a biotite paraschist and on a tonalitic orthogneiss of the Yaminué Complex, and re-evaluate this complex in the broader context of the tectonic evolution of the Patagonia composite terrane. In the metasedimentary unit (msuYC), the youngest detrital zircon dated at 318 ± 5 Ma (Mississippian/Pennsylvanian boundary) indicates a Pennsylvanian (or younger) depositional age. The three main age populations peak at 474, 454 and 374 Ma. Preliminary Hf isotope data for two detrital zircons (447 and 655 Ma) yielded ε(Hf) values of −0.32 and 0.48, indicating that their primary sources contained small amounts of recycled crustal components (of Calymmian age; T DM 1.56 Ga). Zircons from the orthogneiss (miuYC; intrusive into msuYC) show a crystallization age of 261.3 ± 2.7 Ma (Capitanian; late middle Permian) which is broadly coeval with deformation, and Neoarchean–Paleoproterozoic inheritance. Meaningful core-rim relationship between Neoarchean zircon cores and late Permian rims is well defined, indicating the occurrence of Archean crust in this sector of Patagonia. Hf T DM of Permian zircons is mainly Meso-Paleoarchean (2.97–3.35 Ga), with highly negative ε(Hf) values (ca. −33). Hf T DM of inherited Neoarchean zircon cores is also Meso-Paleoarchean (3.14–3.45 Ga) but more juvenile (ε(Hf) = −0.3). Hf isotopes reinforce the presence of unexposed ancient crust in this area. Combining geological and isotope data, as well as geophysical models, we identify the Yaminué Complex within the La Esperanza-Yaminué crustal block flanked by two other, distinct crustal blocks: the Eastern block which forms part of the Patagonia terrane sensu stricto, located in the eastern Patagonian region, and the Western block forming part of the Southern Patagonia terrane. Their origins and timing of amalgamation to form the Patagonia composite terrane are also discussed. [Copyright &y& Elsevier]

This work presents the first results of dating of detrital zircons ( dZr) from the Lower Paleozoic terrigenous-carbonate rocks of the Cambrian Blåstertoppen (samples 08-137 and 08-142, south of the Wedel Jarlsberg Land) and Ordovician Wiederfjellet (sample K06-17, north of the Land) sequences, which are widespread to the north and south of the Hornsund Fjord, on the southwestern coast of Spitsbergen Island. Against the background of sporadic values of 1-3 Ga, samples K06-17 and 08-142 showed similar spectra of the age distribution of dZr with dominant compact numerous age groups of ∼1.8-1.9 Ga and peaks of the maximum of the probability density of 1850 and 1862 Ma, respectively. The only noticeable difference in these spectra is the presence of a young grain of 541 Ma in sample 08-142 (with a very good value of concordance), which is close to the suggested Cambrian age of formation of the Blåstertoppen sequence. The distribution of the dZr ages in sample 08-137 is significantly distinct. First, the general age range is narrower: 1.15-1.95 Ga (no Archean ages). Second, the age of 1.8-2.0 Ga dominant in the other two samples corresponds to only one grain. Thus, although samples 08-137 and 08-142 were taken from closely located levels of the section of the Cambrian Blåstertoppen sequence (in the same interception), the age spectra of dZr from these samples differ cardinally. The statistical Kolmogorov-Smirnov test quantitatively supports the visual similarity of age spectra of dZr from samples K06-17 and 08-142 ( p = 0.913) and the distinction of those from samples 08-142 and 08-137 ( p = 0). Thus, the provenance areas, which supplied the clastic material to the sedimentary basin, whose remnants are presently located in the southwestern part of Spitsbergen, abruptly changed in the Cambrian. The basal levels of the Cambrian section of this basin (sample 08-137) were mostly formed due to accumulation of the erosion products of the local (Spitsbergen) sources: metarocks of the Eimfjellet Group located in the south of the Wedel Jarlsberg Land and of the Smerenburgfjord Group abundant on the Albert I Land. The dZr age spectrum is a print of the ages of the Late Paleoproterozoic-Mesoproterozoic (pre-Grenville) basement unaffected by assemblage of Rodinia. Then the conditions changed and the basin became to accumulate the material from the remote regions, significant parts of which were the areas of ancient cratons, including Archean blocks. The general sedimentation conditions did not change considerably, because the rock type remained the same. [ABSTRACT FROM AUTHOR]

Coupled U–Pb and Lu–Hf LA-ICP-MS detrital and igneous zircon data were obtained from metasedimentary sequences (Kaserer Formation, Schmirntal Quartzite, Seidlwinkel Formation, Bündnerschiefer Basin, Riffler Basin) of the western Tauern Window (Eastern Alps). Results show maximum deposition ages between the Late Permian and the Triassic, indicating protracted sedimentation and magmatism between the Late Paleozoic and the Mesozoic. The Lu–Hf fingerprint shows a change from subchondritic to variable subchondritic to suprachondritic compositions at ca. 290 Ma, possibly documenting the transition from Late Paleozoic Variscan post-collisional processes to intracontinental extension. Lithospheric thinning and magmatic underplating may explain the observed Hf isotopic evolution as the result of mixing of crustal and mantellic sources. From a paleogeographical perspective, results confirm that the Tauern Window was situated between Alpine basement units (South Alpine, Austroalpine and External Massifs) and the Bohemian Massif during the Permian–Triassic. [ABSTRACT FROM AUTHOR]

The formation and evolution of the ancient continental crust are crucial issues in solid-earth geology which are commonly associated with global tectonic events and the formation of economically valuable magmatic-hydrothermal ore deposits. The Cathaysia Block, one of the ancient continents in Southeast Asia, can be subdivided into two parts: the West Cathaysia Block and the East Cathaysia Block. Unlike the East Cathaysia Block, no Precambrian rocks are exposed in the West Cathaysia Block, constraining further understanding of the formation and evolution of this block. In this study, a total of four hundred and thirty-three zircon U-Pb dating analyses and two hundred and eighteen Lu-Hf isotopic analyses on zircon grains from the Jurassic Dengfuxian granites and Ordovician Tanghu granites, Nanling Range, were carried out. LA-ICP-MS zircon U-Pb dating yields mean average 206Pb/238U ages of 152.6 ± 2.2 Ma (MSWD = 1.6) and 442.4 ± 1.7 Ma (MSWD = 3.8), which are regarded as the rock-forming age for the Jurassic Dengfuxian granites and Ordovician Tanghu granites, respectively. The 207Pb/206Pb ages of the inherited zircons from the Jurassic Dengfuxian granites and Ordovician Tanghu granites range from 522 Ma to 3395 Ma, hosting two major peaks at the 0.9–1.0 Ga and 2.4–2.5 Ga. In contrast to the East Cathaysia Block, the West Cathaysia Block lacks the age peak of 1.8–1.9 Ga, indicating that the West Cathaysia Block was not influenced by the assembly of the Columbia supercontinent in the Paleo-Proterozoic. In combination with the Lu-Hf isotopes, we proposed that the crust evolution of the West Cathaysia Block in Archean is dominated by juvenile crustal growth events, and dominated by the crustal reworking since the Proterozoic. The long duration of crustal reworking in the West Cathaysia Block resulted in the enrichment of lithophile elements (e.g., W, Sn, Nb, and Ta) in the crust of that region. Therefore, the Jurassic granites in the Nanling Range, which are mainly derived from the partial melting of Proterozoic basement rocks, became associated with large-scale tungsten polymetallic mineralization. [ABSTRACT FROM AUTHOR]

Abstract: Meta-sedimentary and igneous rocks preserved in the hanging wall of the Paralana Fault, northern Mount Painter Province, record a protracted (ca. 1600Myr) multi-staged metamorphic and poly-deformational evolution related to Mesoproterozoic and Palaeozoic orogenic events. The Mount Painter Province was located near the margin of both the South Australian Craton and the North Australian Craton, which allows comparisons of the tectonic evolution of these margins and provides context for the evolution of the eastern Proterozoic Australia for both the Columbia and Gondwana supercontinents. Within the Mount Painter Province meta-sedimentary rocks form part of a basin system developed adjacent to the margins of the Gawler Craton and Curnamona Province following the Olarian–Wartakan orogenic system. Sedimentation was followed by ca. 1590–1552Ma ductile deformation (D1–D3) at mid to upper crustal levels preserving a rapid (ca 6Myr) burial and exhumation cycle. Initial deformation is characterised by the development of a layer parallel fabric (S1). S1 is overprinted by recumbent north-verging folds (F2) formed during mid to upper amphibolite facies peak metamorphism (M2), which are overprinted by tight, upright shallow NE–SW plunging folds (F3). D3 folds developed contemporaneous with sinistral oblique shearing and the development of proto-mylonitic to ultra-mylonitic fabrics along the Paralana Fault Zone. The timing of D3 deformation is constrained by the development of a penetrative steeply dipping foliation (S3) in the ca. 1585–1569Ma shallowly emplaced Mount Neill Granite and relatively undeformed granites dated at ca. 1552Ma. Further constraint on the absolute timing of Mesoproterozoic tectonism is provided through the dating of zircon growth from samples of the meta-sedimentary Radium Creek Metamorphics. This dating reveals a 1555±16Ma metamorphic event, interpreted to be the consequence of M3 amphibolite facies, regional metamorphism and accompanying metasomatism. The transition between D2 and D3 is interpreted to reflect a shift from ca. 1591–1585Ma N–S shortening to ca. 1585–1552Ma NW–SE shortening. This episode of orogenesis is correlated with the ca. 1585–1540Ma Kararan Orogeny in the northern Gawler Craton, which distinctly postdates the ca 1600–1590Ma Olarian Orogeny as previously interpreted. The Mesoproterozoic structural architecture was reactivated during Neoproterozoic extension (D4) and the ca. 500Ma Delamerian Orogeny. Delamerian structures are formed in a predominantly brittle regime. Early thin-skinned thrusting was followed by thick-skinned deformation (D5–D6); during which open F5 folds developed above oblique lateral ramps, and produced type 0 overprinting patterns with F3 Mesoproterozoic folds. Steeply plunging F6 buckle folds with SE-trending axial traces are the last phase of deformation recorded. Both Mesoproterozoic ductile deformation phases and the Palaeozoic ductile-brittle to brittle overprints were focussed along the Paralana Fault, emphasising the repeated long-lived evolution of this crustal scale fault system. [Copyright &y& Elsevier]

The article offers study of the tectonic evolution history of the Early Paleozoic in the middle of the north margin of the North China Craton, and provides evidence for the regional tectonic evolution and solution of geological problems. Topics include samples for zircon dating, and zircon Hf isotopic analyses were collected from tonalite in the Yangjiawopu village, Faku County, Liaoning Province; and concluded the discovery of Early Paleozoic igneous rocks in the Songliao Basin.

Late Paleozoic (Variscan) magmatism is widespread in Central Europe. The Lusatian Block is located in the NE Bohemian Massif and it is part of the Saxothuringian Zone of the Variscan orogen. It is bordered by two major NW-trending shear zones, the Intra-Sudetic Fault Zone towards NE and the Elbe Fault Zone towards SW. The scarce Variscan igneous rocks of the Lusatian Block are situated close to these faults. We investigated 19 samples from Variscan plutonic and volcanic rocks of the Lusatian Block, considering all petrological varieties (biotite-bearing granites from the Koenigshain and Stolpen plutons, amphibole-bearing granites from three boreholes, several volcanic dykes, and two volcanites from the intramontane Weissig basin). We applied whole-rock geochemistry (18 samples) and zircon evaporation dating (19 samples). From the evaporation data, we selected six representative samples for additional zircon SHRIMP and CA–ID–TIMS dating. For the Koenigshain pluton, possible protoliths were identified using whole-rock Nd-isotopes, and zircon Hf- and O-isotopes. The new age data allow a subdivision of Variscan igneous rocks in the Lusatian Block into two distinct magmatic episodes. The spatial relation of the two age groups to either the Elbe Fault Zone (298–299 Ma) or the Intra-Sudetic Fault Zone (312–313 Ma) together with reports on the fault-bound character of the dated intrusions suggests an interpretation as two major post-collisional faulting episodes. This assumption of two distinct magmatic periods is confirmed by a compilation of recently published zircon U–Pb CA–ID–TIMS data on further Variscan igneous rocks from the Saxothuringian Zone. New geochemical data allow us to exclude a dominant sedimentary protolith for the Koenigshain pluton as supposed by previous investigations. This conclusion is mainly based on new O- and Hf-isotope data on zircon and the scarcity of inherited zircons. Instead, acid or intermediate igneous rocks are supposed as the main source for these I-type granitoids from the Koenigshain pluton. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the felsic magmatic evolution and the role of the post-collisional process in continental crustal growth at convergent margins in the Central Qilian Belt (CQB) in northwestern China as of December 2015. It focuses on the new geochemical and zircon uranium-lead (U-Pb) and hafnium (Hf) isotope data for representative granitoids (sensu lato) of the CQB. Also cited is the Paleaozoic evolution of the Qilian orogen.

[Display omitted] • Porphyry Cu mineralizations are closely related to adakitic igneous rocks. • SHRIMP zircon dating yields a middle Carboniferous intrusion age. • Zogdor granodiorite and monzogranite were derived from a depleted mantle source. The Zogdor Cu occurrences are located in the Gurvansayhan island arc terrane of southern Mongolia, which corresponds to the southern part of the Central Asian Orogenic Belt (CAOB). The major porphyry type copper–gold (molybdenum) mineralized belt including Oyu Tolgoi, Tsagaan Suvarga, Shuteen, and Kharmagtai deposits are located in this terrane and were known to have formed during 372–324 Ma. The Zogdor Cu occurrences are found within this porphyry Cu-Au mineralized belt and are limitedly distributed in granitoids including granodiorite and monzogranite. In this study, we present new SHRIMP zircon U-Pb geochronology, LA-MC-ICPMS zircon Lu-Hf isotopes, and geochemical data for the granitoids in the Zogdor Cu occurrences and provide a new tectonic model including igneous activities and Cu mineralization in southern Mongolia. The emplacement ages of granodiorite and monzogranite are 329.1–326.4 Ma, and 329.9–326.1 Ma, respectively. All zircons have positive ε Hf values corresponding to two-stage model ages (T 2DM) ranging from 581 to 331 Ma, possibly demonstrating that late Neoproterozoic to middle Carboniferous juvenile continental crust growth was derived from a depleted mantle source. Both granitoids are characterized by high Al 2 O 3 and Sr, and low Y and Yb contents, as well as high Sr/Y and (La/Yb) N ratios, which are typical geochemical characteristics of adakites. The trace elements are characterized by an enrichment in the large ion lithophile elements (e.g., Cs, Rb, Ba, and Sr) and a depletion in the high field strength elements (e.g., Nb, P, and Ti), indicating that these granitoids intruded in subduction tectonic settings. In conclusion with data from previous studies, the intermittent igneous activities during the Cambrian to Ordovician (519–482 Ma), middle Devonian (374–363 Ma), middle to late Carboniferous (353–304 Ma), and early Permian (298–286 Ma) took place in the southern Mongolia and porphyry copper mineralizations seem to be closely related the middle Devonian and middle Carboniferous adakitic or adakite-like magmatism. The Lu-Hf isotopic results for these associated granitoids including previous Rb-Sr and Sm-Nd isotopic studies imply that the Neoproterozoic to middle Carboniferous juvenile continental growth derived from a depleted mantle source. The middle Devonian and middle Carboniferous magmatic activities triggered by the subduction of the Paleo-Asian Oceanic plate and formed the porphyry copper deposits in the southern Mongolia. [ABSTRACT FROM AUTHOR]

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 late Paleozoic tectonic framework of the southeastern Central Asian Orogenic Belt is key to restricting the accretion orogeny between the Siberia Craton and the North China Craton. To clarify the framework, petrogenesis of early Permian intrusive rocks from southeastern Inner Mongolia was studied. Zircon U‐Pb dating for bojite and syenogranite from Ar‐Horqin indicate that they were emplaced at 288–285 Ma. Geochemical data reveal that the bojite is highly magnesian and low‐K to middle‐K calc‐alkaline, with E‐MORB‐type REE and IAB‐like trace element patterns. The syenogranite is a middle‐K calc‐alkaline fractionated A‐type granite and shows oceanic‐arc‐like trace element patterns, with depleted Sr‐Nd‐Hf isotopes, (87Sr/86Sr)I = 0.7032–0.7042, εNd(t) = +4.0 to +6.6 and zircon εHf(t) = +11.14 to +14.99. This suggests that the bojite was derived from lithospheric mantle metasomatized by subducted slab melt, while the syenogranite originated from very juvenile arc‐related lower crust. Usng data from coeval magmatic rocks from Linxi–Ar‐Horqin, the Ar‐Horqin intra‐oceanic arc was reconstructed, i.e., initial transition in 290–280 Ma and mature after 278 Ma. Combined with regional geological and geophysical materials in southeastern Inner Mongolia, an early Permian tectonic framework as 'one narrow ocean basin of the PAO', 'two continental marginal arcs on its northern and southern' and 'one intra‐oceanic arc in its southern' is proposed. [ABSTRACT FROM AUTHOR]

Plagiogranites are a volumetrically minor component of oceanic crust and ophiolites, but offer an opportunity to probe the processes and mechanisms by which felsic crusts were produced from the mafic oceanic crusts. The Qinling-Tongbai orogenic belt in central China is a typical composite orogenic belt that records the amalgamation processes between the North China Block and the South China Block. The Erlangping unit represents an accretionary oceanic unit in the Qinling-Tonbai orogenic belt and contains minor plagiogranites, which have received little attention. In this study, we carried out an integrated study of U–Pb geochronology and Hf–O isotopes in zircon, as well as whole-rock isotope and geochemical analyses for felsic rocks in the Erlangping unit. These rocks occur as dikes to stocks intruding ambient basalts. They have relatively high Na 2 O and Al 2 O 3 , moderate MgO and low K 2 O contents, and are classified as oceanic plagiogranites. Zircon U–Pb geochronology yielded formation ages of ca. 465 Ma. Zircon δ18O compositions (4.4–5.1‰) are lower than or similar to those of zircons from normal mantle. The low TiO 2 content, elevated Zr/Hf, and light rare-earth element (LREE) enrichments in these rocks indicate that these plagiogranites were generated by partial melting of hydrothermally altered oceanic crust. These samples have more depleted whole-rock ε Nd (t) (+4.4 to +5.1) and zircon ε Hf (t) (+10.5 to +12.8) values than the basaltic wall-rocks, implying they were derived from a newly accreted oceanic arc. Taking into account the tectonic framework of the broader Qinling Orogenic belt, a subduction-induced magma flare-up in the Ordovician could have triggered the anatexis of the existing Erlangping oceanic arc, and in turn generated these plagiogranites. Partial melting of oceanic crust that has been enriched in a subduction system may be an important mechanism for the formation and maturation of continental crust in oceanic arc settings. • Plagiogranite dikes and stokes in the Erlangping unit were emplaced at ca. 465 Ma. • The plagiogranites were formed by partial melting of lower oceanic crust. • Subduction induced the anatexis of the existing Erlangping oceanic arc. • Partial melting of ocean crust is important for the maturation of continental crust. [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]

Highlights • Detrital zircon ages and Hf isotopes, Nyainqentanglha Group, central Lhasa terrane. • The earliest coarse clastic rocks in central Lhasa terrane deposited at 803 ± 5 Ma (Tonian). • Some Mesoproterozoic zircons may come from the terranes that became the Himalayas. • Neoproterozoic zircons may be derived from convergent plate margin system along NW Rodinia. • Lhasa and Himalaya may have been adjacent before Gondwana's amalgamation. Abstract Cimmerian terranes in Tibet are thought to be as old as Archean or as young as Neoproterozoic or even early Paleozoic in age. However, their Precambrian history and their role in the assembly and dispersal of early supercontinents (e.g., Rodinia) are still poorly known. Here, U-Pb dating, trace-element geochemistry and Lu-Hf isotopes of detrital zircons (351 grains) from the Nyainqentanglha-Group clastic rocks, the earliest strata overlying the Lhasa Block (South Tibet), are used to constrain the provenance of the sediments and test paleogeographic and tectonic models for the Lhasa Block during the breakup of the Rodinia supercontinent. The youngest detrital zircon cluster (803 ± 5 Ma) in the clastic rocks and granitic dykes (797 ± 10 Ma) intruding them constrain the deposition age close to 800 Ma. Four main groups of detrital zircons in these sediments record several sources, including Mesoproterozoic and Neoproterozoic juvenile terranes, a Grenvillian orogenic belt and an Archean continental-crust component. Detrital-zircon age distributions and Lu-Hf isotopic data reveal the variation of the sedimentary provenance and suggest its affinity to the Himalaya and/or the East Africa Orogen. These results show that the Lhasa Block was probably located within a giant convergent plate margin system surrounding the Rodinia supercontinent during its breakup in the Tonian time. [ABSTRACT FROM AUTHOR]

The Tauride block in Turkey is a peri-Gondwana, Cadomian-type terrane that rifted from the Afro-Arabian margin of Gondwana in the Permo-Triassic and re-accreted to Arabia in the Neogene. In the Karacahisar dome in the southern-central Taurides, Neoproterozoic basement metasediments and intrusive rocks are overlain by Cambro-Ordovician, Carboniferous and Triassic sediments. We studied U–Pb–Hf in zircons from major rock units exposed in Karacahisar in order to constrain the Cadomian crustal evolution of the Taurides, to evaluate the provenance of the Neoproterozoic and overlying sediments, to constrain the paleogeography of the Taurides, and to assess their linkage to Gondwana. The Neoproterozoic metasediments are low-grade metamorphic wacke-type turbidites that evolved in a broad back-arc basin peripheral to Afro-Arabia. Their detrital zircon U–Pb signal comprises a preponderance (40–68%) of Neoproterozoic-aged zircons (peak ages defined at 635 and 830 Ma), indicating that the sedimentary pile was built mainly from the erosion of Pan-African terranes from Afro-Arabia. The εHf values of the younger population (635 Ma) are mostly positive, indicating derivation from a juvenile arc, whereas Cryogenian–Tonian detrital zircons spread vertically (− 25 < εHf < 15), indicating a different provenance where mixing of juvenile magmas with Paleoproterozoic to Neoarchean crust was widespread. An unusually high proportion of pre-Neoproterozoic zircons is found in all Cadomian metasediments, including up to 31% Grenvillian-aged (ca. 1.0 Ga) and up to 35% of ca. 2.5 Ga zircons; about a third of the latter possess positive εHf values. Because only minor exposures of 1.0 and 2.5 Ga crustal vestiges are currently known in North Africa and Arabia, we infer that pre-Neoproterozoic terranes were dispersed within the Cadomian realm itself. The youngest detrital zircons in all Cadomian metasediments concentrate at 0.58 Ga, indicating that the proto-Cadomian back-arc basin was formed towards the Late Ediacaran. The termination of Neoproterozoic sedimentation is marked by the intrusion of dyke swarms yielding a U–Pb zircon age of 544 ± 4 Ma, coeval with magmatism in other Cadomian basement units in the Taurides (e.g., Sandıklı and Menderes massif). Shortly afterwards the Tauride basement was overstepped by the Cambro-Ordovician platform. From the Cambrian to the Triassic, the U–Pb–Hf detrital zircon signal of the cover sediments in the Taurides in Karacahisar portrays remarkable resemblance to that of typical North Gondwana Cambro-Ordovician cover sediments, and shows that the Taurides accreted to Afro-Arabia by the onset of the Cambrian. The short time interval between Cadomian basin fill and deposition of the Cambrian platform implies that the Taurides evolved within a short distance from their present position relative to the Afro-Arabian margin of Gondwana. The Gondwana provenance of the Tauride sedimentary cover is maintained through the Upper Triassic, indicating that Neo-Tethys rifting was incipient at that time, allowing Afro-Arabian detritals to reach the Taurides. [ABSTRACT FROM AUTHOR]

The paper presents first data on isotopic U–Pb study (LA-ICP-MS method) of zircon from intrusive rocks of the Adyrtor intrusions – a group of small intrusives situated in the easternmost part of the deep-seated fault system of the "Nikolaev Line." Here, these intrusions cut through one of the oldest (1.8–2.6 Ga) complexes of the basement rocks of Tien Shan (metamorphic rocks of the "Kuilyu suite"). These intrusive rocks belong to the high-potassic calc-alkaline to shoshonitic series, with some geochemical signatures also of anorogenic (A-type) magmatism. These intrusions are accompanied by skarn and porphyry W–Mo–Cu–Au mineralization. Together with the other Au, W, and Cu deposits and occurrences, they are parts of the extended metallogenic belt of Tien Shan. The concordant isotopic U–Pb age data for zircon autocrysts indicate the crystallization of quartz syenite (330.7 ± 4.3 Ma) and quartz monzonite (329.5 ± 5.8 Ma) in the latest Early Carboniferous. The distinct W–Mo specialization of ore mineralization related to the intrusions studied is in agreement with the post-collisional tectonic setting during their emplacement, despite their older or similar age compared to the ore-bearing plutons in more western segments of the Middle Tien Shan, which corresponded to a subduction-related setting. This supports the possibility of the "scissor-like" (from east to west) closure of the Turkestan paleoocean that resulted in the earlier cessation of subduction in the eastern Tien Shan compared to the western Tien Shan. The rocks also contain zircon xenocrysts with older (on the order of 1.7–2.6 Ga) age, which is in agreement with the age of the host metamorphic rocks of the Tarim craton basement. This highlights the possibility of magma chamber development in the continental crust, together with the magma chambers in the metasomatically-enriched subcontinental upper mantle, the latter being common for high-potassic magmatism. [ABSTRACT FROM AUTHOR]

The Ellsworth-Whitmore Mountain terrane of central Antarctica was part of the early Paleozoic amalgamation of Gondwana, including a 13,000 m section of Cambrian- Permian sediments in the Ellsworth Mountains deposited on Grenville-age crust. The Jurassic breakup of Gondwana involved a regional, bimodal magmatic event during which the Ellsworth-Whitmore terrane was intruded by intraplate granites before translation of the terrane to its present location in central Antarctica. Five widely separated granitic plutons in the Ellsworth-Whitmore terrane were analyzed for their whole-rock geochemistry (X-ray fluorescence), Sr, Nd, and Pb isotopic compositions, and U-Pb zircon ages to investigate the origins of the terrane magmas and their relationships to mafic magmatism of the 183 Ma Karoo-Ferrar large igneous province (LIP). We report high-precision (±0.1 m.y.) isotope dilution- thermal ionization mass spectrometry (IDTIMS) U-Pb zircon ages from granitic rocks from the Whitmore Mountains (208.0 Ma), Nash Hills (177.4-177.3 Ma), Linck Nunatak (175.3 Ma), Pagano Nunatak (174.8 Ma), and the Pirrit Hills (174.3-173.9 Ma), and U-Pb sensitive high-resolution ion microprobe (SHRIMP) ages from the Whitmore Mountains (200 ± 5 Ma), Linck Nunatak (180 ± 4 Ma), Pagano Nunatak (174 ± 4 Ma), and the Pirrit Hills (168 ± 4 Ma). We then compared these results with existing K-Ar ages and Nd model ages, and used initial Sr, Nd, and Pb isotope ratios, combined with xenocrystic zircon U-Pb inheritance, to infer characteristics of the source(s) of the parent magmas. We conclude that the Jurassic plutons were not derived exclusively from crustal melts, but rather they are hybridized magmas composed of convecting mantle, subcontinental lithospheric mantle, and lower continental crustal contributions. The mantle contributions to the granites share isotopic similarities to the sources of other Jurassic LIP mafic magmas, including radiogenic 87Sr/86Sr (0.706-0.708), unradiogenic 143Nd/144Nd (εNd < -5), and Pb isotopes consistent with a low-μ source (where μ = 238U/204). Isotopes and zircon xenocrysts point toward a crustal end member of predominantly Proterozoic provenance (0.5-1.0 Ga; Grenville crust), extending the trends illustrated by Ferrar mafic intrusive rocks, but contrasting with the inferred Archean crustal and/or lithospheric mantle contributions to some basalts of the Karoo sector of the LIP. The Ellsworth-Whitmore terrane granites are the result of mafic rocks underplating the hydrous crust, causing crustal melting, hybridization, and fractionation to produce granitic magmas that were eventually emplaced as post-Ferrar, within-plate melts at higher crustal levels as the Ellsworth-Whitmore terrane rifted off Gondwana (47°S) before migrating to its current position (82°S) in central Antarctica. [ABSTRACT FROM AUTHOR]

The geologic history of the Western Tianshan region is important for understanding the evolution of the Central Asian Orogenic Belt and accretionary orogenesis. Paleozoic and Mesozoic igneous rocks are present along the northern margin of the Yili Block; however, studies of Paleozoic subduction and collisional events have been relatively limited. Published geochronologies of Middle Devonian magmatic rocks in this region are also lacking. Therefore, this study analyzed the zircon U–Pb ages and major and trace elemental compositions of three granite types collected from Biezhentao Mountain (Wenquan County, Western Tianshan). The medium-grained diorite (384.1 ± 3.6 Ma) and diorite–porphyrite (382 ± 3.2 Ma) are silica-rich, weakly peraluminous, alkali-rich, enriched in large-ion lithophile elements, depleted in high field strength elements, and belong to the calc–alkaline series, with A-type granite characteristics. The monzogranite (423.3 ± 9.4 Ma) exhibits A-type granite characteristics and belongs to the peraluminous calc–alkaline series. The findings suggest that the granitoids recorded two stages of tectonomagmatism during the Middle Devonian–Late Silurian. The Middle Devonian medium-grained diorite and diorite–porphyrite formed in a back-arc extensional setting, whereas the Late Silurian monzogranite formed in an active continental margin setting during the subduction of the North Tianshan Ocean. These results provide insights into the tectonic and magmatic processes that occurred during the evolution of the Western Tianshan region and the formation and evolution of the Central Asian Orogenic Belt. [ABSTRACT FROM AUTHOR]

This paper presents the results of U–Pb dating of detrital zircons from six metasedimentary rocks in the Taowan and Kuanping groups in the northern margin of the North Qinling Orogenic Belt (NQB), Central China, for constraining the tectonic affinity of the NQB, the existence time and tectonic features of the Kuanping Ocean and the accurate northern boundary of the NQB. Zircon U–Pb dating indicates that the protoliths of the two metasedimentary rocks from the upper and lower parts of the Taowan Group were deposited later than ∼1111 and ∼871 Ma respectively. However, the protoliths of the four metasedimentary rocks from different layers of the Kuanping Group were deposited later than ∼781, ∼668, ∼515 and ∼477 Ma, respectively, suggesting that the Taowan Group and the Kuanping Group both have an abnormal or non-Smithian stratigraphic sequence. The age populations and predominant peak ages of detrital zircon grains from the Mesoproterozoic–middle Neoproterozoic metasedimentary rocks in the Taowan and Kuanping groups indicate that their provenances were mainly attributed to the NQB and subordinately from the Yangtze Craton (YZC), suggesting that the two groups both belong to the NQB and the northern boundary of the NQB should be placed to the north of the Taowan Group, which can be called the Paleo-Luonan–Luanchuan Fault. However, the Nd–Pb whole-rock isotopes, zircon Hf isotopes and trace element compositions of the Precambrian basement rocks and the Neoproterozoic granitic magmatic events in the NQB are significantly different from those in the YZC, suggesting that the NQB was more likely to be an independent microcontinent adjacent to the YZC from the Mesoproterozoic to the Neoproterozoic, and experienced a unique geological history. On the other hand, together with the record of the oldest MORB-type basalt with an age of 1445 Ma in the Kuanping Group, the first late Mesoproterozoic sedimentary record (∼1111 Ma) in the Taowan Group, to be reported using precise geochronological data in this study, it indicates that the Kuanping Ocean separated the NQB from the NCC that had already existed to the north of the NQB before the Mesoproterozoic, and was a major ocean basin which had lasted for a long time, rather than as a back-arc basin. [ABSTRACT FROM AUTHOR]