Detrital Zircon Research Articles

Regional unconformities dating closure of the Paleo-Tethys Ocean in the late Anisian (Middle Triassic)

The timing and tectonic evolution of the closure of the Paleo-Tethys Ocean remain controversial, with dates ranging from Late Permian time to the Jurassic. Field mapping shows that the regional Kaixinling unconformity lies between the Upper Permian−Middle Triassic Nayixiong Formation and Middle−Upper Triassic Jiapila Formation in the North Qiangtang terrane of China. It is characterized by ∼50-cm-thick weathering crust and abrupt changes in stratigraphy, lithofacies, and biological realms in the Kaixinling area. Zircon U-Pb dating of interlayered tuffs and siliceous dolomite accurately constrained formation of the Kaixinling unconformity to 243−239 Ma (Anisian−Ladinian). Detrital zircon grains from the Nayixiong and Jiapila formations show unimodal peak ages of 256 Ma and 302 Ma, respectively, which indicate provenance mainly from the northern magmatic arc. The absence of Pan-African ages rules out the basement source of the North Qiangtang terrane. These data, integrated with contemporaneous paleolatitude data from the North Qiangtang terrane, suggest that the development of the Kaixinling unconformity was associated with the tectonic transition from the Jinshajiang oceanic subduction-related retroarc foreland basin to the collision-related intracontinental foreland basin in the North Qiangtang. Thus, development of the unconformity marked the closure of the Jinshajiang Ocean at 243 Ma. Our results further highlight diachronous suturing of the Paleo-Tethys Ocean from the Ailaoshan Ocean in Early Triassic time to the Jinshajiang Ocean in Middle Triassic time, which signified the broader-scale reconstruction of the Pangea supercontinent.

Arc sections correlation along the Gondwana margin: Dynamic shifts tracked by detrital zircon

Arc sections correlation along the Gondwana margin: Dynamic shifts tracked by detrital zircon

Origin and evolution of the Qiangtang block, northern Tibetan Plateau: New insights from detrital zircon U-Pb geochronology and Lu-Hf isotopic compositions

Origin and evolution of the Qiangtang block, northern Tibetan Plateau: New insights from detrital zircon U-Pb geochronology and Lu-Hf isotopic compositions

Detrital zircon chronology of the Guryong Group, the eastern part of the Gyeonggi Massif, Korea: Implication for the Late Paleozoic pre-collisional evolution in the Korean Peninsula

Detrital zircon chronology of the Guryong Group, the eastern part of the Gyeonggi Massif, Korea: Implication for the Late Paleozoic pre-collisional evolution in the Korean Peninsula

Integrated chemostratigraphy and detrital zircon geochronology of the Ediacaran–Cambrian transition in the Western Anabar Uplift: Implications for the Neoproterozoic evolution of the northern Siberian Platform

Integrated chemostratigraphy and detrital zircon geochronology of the Ediacaran–Cambrian transition in the Western Anabar Uplift: Implications for the Neoproterozoic evolution of the northern Siberian Platform

The tectonic evolution of the pre-Mesozoic key period in the Tarim Basin: Constraints from U-Pb geochronology of paleozoic detrital zircons in the central uplift zone

The tectonic evolution of the pre-Mesozoic key period in the Tarim Basin: Constraints from U-Pb geochronology of paleozoic detrital zircons in the central uplift zone

Response of source-to-sink patterns during the Mesozoic to tectonic setting in southwestern Tarim Basin: Insights from detrital zircon geochronology and morphology

Response of source-to-sink patterns during the Mesozoic to tectonic setting in southwestern Tarim Basin: Insights from detrital zircon geochronology and morphology

PALEOMAGNETISM OF THE VOROGOVKA GROUP: SUBSTANTIATING THE VENDIAN GEOMAGNETIC PHENOMENON (Yenisei Ridge)

We report new paleomagnetic data for the carbonate-terrigenous section of the Vorogovka Group at its type locality along the Vorogovka River in northwestern Yenisei Ridge. The data is synthesized with existing information on the age of the rocks, including our new determinations using detrital zircons from sandstones and Sr chemostratigraphy for carbonate rocks from all three stratigraphic units of the group: Severnaya Rechka, Mutnina, and Sukhaya Rechka formations. These findings definitively indicate a younger age for the strata, in the range of 580–535 Ma, with a relatively rapid rate of sedimentation, contrary to previous estimates. The anomalous paleomagnetic record typical for the Vendian (Ediacaran)–early Cambrian period and the proximity of the paleopoles established for Siberia both suggest that the rocks formed over an even shorter interval, between 580 Ma and 560 Ma. The data shows that the paleomagnetic record of the Vorogovka Group contains, in addition to a viscous component, a metachronous magnetization, presumably of Cambrian age, and two coeval components of primary origin. The coexistence of these components in a single section does not correspond to actualistic ideas about the prevailing geocentric axial dipole geometry of Earth’s magnetic field and is the subject of a long-standing debate. Our analysis of the new data and its comparison with existing paleomagnetic records for Siberia provided new insights into the interpretation of the Vendian geomagnetic phenomenon within an original hypothesis. According to this model, the second magnetization component in the Vendian–lower Cambrian section is explained by a sharp decline in the main dipole component of the geomagnetic field to values comparable to the intensity of the global magnetic anomalies. This phenomenon distorted the conventional paleomagnetic record to varying degrees, and during periods of ultra-low dipole strength, it sometimes entirely replaced the usual record. Accordingly, these paleomagnetic vectors no longer oriented toward the magnetic pole but instead aligned with the nearest magnetic anomaly. This hypothesis is used to interpret not only the paleomagnetic vectors observed in the Vorogovka Group but also the entire set of paleomagnetic data for the Vendian–early Cambrian formations of Siberia.

MAGMATISM OF THE OMOLON CRATONAL TERRANE (northeastern Russia): GEOCHRONOLOGY, GEOCHEMISTRY, AND GEODYNAMICS

A long history of diverse magmatism of the Omolon Cratonal Terrane (OM) is traced from the Paleoproterozoic to the Late Miocene. The new isotope-geochronological (U-Pb, 40Ar/39Ar) dating and geochemical data allowed us to reliably identify nine main episodes and geodynamic settings of magmatism, as well as to discuss in detail potential sources of detrital zircon populations in sedimentary rocks of northeastern Russia. The earliest manifestations of fleck gneisses of the anorogenic Upper Оmolon complex with an age of about 1.9 Ga reflect the rifting and the beginning of destruction of the Precambrian basement which has the age of about 3.2 Ga. The ongoing rifting of the OM is traced in the Riphean, when swarms of dikes and small bodies of the gabbro-diabase Strelkin complex were intruded. In the Silurian (433–425 Ma), in oblique shears and local extension zones of the OM, plutonic syenite magmas of the Anmandykan and granitoids of the Abkit complexes (ENd from –23 to –10) are intruded. The largest manifestations of plutonic and volcanic magmatism were recorded in the OM in the Late Devonian (from 375 ± 3 to 356 ± 4 Ma), when calc-alkaline suprasubduction volcano-plutonic complexes (Bulun hypabyssal and Kedon volcanic) were formed. The Nd isotopic composition of Devonian magmas (ENd from –20 to –6), with an extremely low content of radiogenic lead isotopes (206Pb/204Pb = 17.2–15.7) indicates their melting from a mature crustal protolith in the OM basement. Early and Middle Jurassic rifting locally manifested on the OM, which are reflected by the Tummin trachybasalt and Omolon essexite-teschenite complexes. The Early Cretaceous (144–133 Ma, ENd from +7 to 0) Namyndykan and Egdegkych granodiorite-monzonite plutonic complexes form suprasubduction zones of an island-arc nature on the northeastern margin of the OM. In the Santonian-Campanian time (~ 85–77 Ma BP), the Early Cretaceous extension zone on the Omolon massif was healed by the Kongin and Viktorin calc-alkaline complexes of the Okhotsk-Chukotka volcanic-plutonic belt. The final stage of magmatism in the OM is represented by intraplate alkali-basaltic volcanism in the interval from 9 to 7 ± 1 Ma. Synchronization in time of the manifestation of the most voluminous Late Devonian suprasubduction magmatism of the OM and basaltic LIP-magmatism of the Vilyui rift in Siberian craton was established. Based on this and comparison with detrital zircon populations from Paleozoic sandstones of northern Siberia, we reconstruct that the OM broke off from the northeastern part of the Siberian craton during the Silurian to Devonian and migrated southeast (in modern coordinates). A vast area of crustal extension and thinning in the Alazeya zone during the Jurassic-Cretaceous time has been reconstructed.

The Neoproterozoic glacial broom

Neoproterozoic snowball Earth events reflect globally frigid conditions thought to have stimulated changes in geochemical cycling with planetary biotic response. We investigated the impact of these events on sediment dynamics, focusing on the detrital zircon record within the Dalradian Supergroup of Scotland and Ireland. Utilizing U-Pb detrital zircon ages, we analyzed changes in sediment provenance throughout the stratigraphy via bootstrapped variance metrics. The coefficient of variance for the detrital zircon load exhibits a first-order increase stratigraphically upward, with marked changes at glaciogenic layers. Points of increased variance align with inputs of older detritus compared to lower, preglacial stratigraphic levels, suggesting intensified erosion and downcutting linked to wet-based glacial activity, with postglacial sediment redistribution. Average detrital zircon apparent density also changes through the stratigraphy, with implications for uranium cycling from the continents into the oceans. While early Ediacaran shale geochemistry implies postglacial oceanic oxygenation, loss of proportionally more uranium-rich detrital zircon across glaciogenic layers suggests that modification to continental weathering also fundamentally contributed to Neoproterozoic geochemical shifts.

Petrogenesis of the Large-Scale Serpentinites in the Kumishi Ophiolitic Mélange, southwestern Tianshan, China

The Kumishi ophiolitic mélange contains well-preserved large-scale serpentinites and their accompanying granulites in the eastern South Tianshan Accretionary Complex (STAC), southwestern Altaids. Previous studies have mainly focused on the thermodynamic conditions and tectonic setting of granulites. However, the petrogenesis of the widespread serpentinites in the Kumishi ophiolitic mélange remains largely unexplored. In this paper, petrological, geochemical, and geochronological studies were carried out on the Kumishi serpentinites, as well as the host sediment and intermediate–felsic volcanic rocks. The serpentinites show variable LOI values of 8.3–16.5 wt% and relatively consistent SiO2/(sum oxides) ratios of 0.81, which demonstrate that the major elements of their protoliths have been preserved well during serpentinization. Multi-trace element and REE diagrams suggest that the protoliths of the Kumishi serpentinites have experienced varying degrees of refertilization, with distinct natures seen between the Yushugou, Tonghuashan, and Liuhuangshan serpentinites. Zircon U-Pb chronology of the Tonghuahsan serpentinites yields a mean age of 355.8 ± 7.3 Ma (MSWD = 1.0, N = 26). Detrital zircons from the host sediment record a maximum depositional age of 375 ± 10 Ma (MSWD = 0.4, N = 3), with a peak at ca.419 Ma. Subduction-related volcanic rocks yield ages of ca.437 Ma. Hence, clues are provided to the petrogenesis of the Kumishi serpentinites, with calls for future in-depth works from an isotopic perspective.

The south margin of the central Altyn is an early paleozoic tectonic unit confirmed by Zircon dating evidence

The south margin of Central Altyn (SMCA) has long been considered as Precambrian stratigraphic unit of the Altyn Orogen. However, their strata attribution is subjected to challenge by the new finding of Siluran-Devonian metamorphic rocks. Aiming to further understand the geological evolution of the SMCA and its relations with the adjacent tectonic units, here we investigate the metasedimentary, metamafic and metagranitic rocks and in turn to re-examine the tectonic characteristics of the region. Detrital zircons from six metasedimentary rocks hold a sharp peak of ~ 452 Ma and moderate peak of 800–1600 Ma, whose spectra characteristics are similar to those of extensional basins formed under subduction setting of active continental margins. Two metamafic rocks and one metagranitic rock obtained crystallization ages for their protolith of c.456 Ma, c.462 Ma and c.457 Ma, which fell in the range of the 462–451 Ma magmatism of South Altyn (SA). These ages are widely distributed from west to east along the SMCA, and congruously indicate its stratum should formed in the Middle- Late Ordovician sedimentary environment under the extensional background of the SA subduction–early exhumation. All rocks record three stages metamorphism by zircons of ~ 430 Ma, ~ 400 Ma and ~ 377 Ma, consistent with previously reported HP pelitic gneiss. These protolith and metamorphic studies suggest that the SMCA should be a Paleozoic subduction-collision zone, rather than Mesoproterozoic sedimentary strata, and it should be separated from the Central Altyn block. Moreover, the similar protolith and metamorphic age have been also widely reported in the North Qaidam (NQ) and Dunhuang (DH) orogen, suggesting they may be the response of the same geological event in different tectonic units.

The clastic record of an early Brasiliano Orogeny: pre-collisional subduction-related metamorphism within the southern Borborema Province through detrital rutile analysis

The ubiquity of detrital zircon in clastic sediments made zircon one of the primary minerals for provenance and tectonomagmatic studies. Its high U-Pb closure temperature (>900 o C), limited growth of new zircon under upper amphibolite-eclogite facies, inherited bias towards felsic sources, and the refractory behavior rarely representing first-cycle sedimentation can hamper the detection of key tectonomagmatic events. Other mineral assemblages, like rutile, formed in medium- to high-grade metapelite and metabasite during high-pressure and low-temperature subduction metamorphism can help to provide a complete record of polyphase orogenic evolution. In this study, we present U-Pb ages and trace elements in detrital rutile from the Ordovician Tacaratu Formation (Tucano-Jatobá Basin) to track the complete polyphase evolution of southern Borborema Province. Coupled U-Pb detrital zircon and rutile analysis revealed that detrital zircon ages lag detrital rutile ages by ca. 100 Ma. Three rutile age peaks at ca. 767 Ma, 669 Ma, and 595 Ma were recognized, agreeing with subduction in magma-poor orogenic phases (lulls) between relatively high magma generation phases (flare-ups). The detrital rutile ages record earlier phases of Brasiliano Orogeny in southern Borborema Province (subduction-related metamorphism; closure of Sergipano Ocean), since this orogeny culminated in the collision of blocks followed by high-temperature metamorphism.

Substantiating the Paleozoic sedimentary record of the tectonic transition from a passive to an active continental margin along the eastern margin of Eurasia

The Jiamusi Massif in the eastern margin of Eurasia, located at the tectonic transition belt between the Paleo-Asian Ocean and the Paleo-Pacific tectonic domain, underwent a pivotal transition from a passive to active continental margin during the late Paleozoic. However, the exact timing and geodynamics of this transition remain controversial. To address this issue, this paper presents new petrological, mineralogical, detrital zircon U-Pb geochronology, and zircon trace element analyses of sedimentary rocks sourced from both the Heitai and Zhenzishan formations in the Jiamusi Massif. The results indicate that the Heitai Formation is a clastic-carbonate rock association deposited on stable crust. In contrast, the Zhenzishan Formation is a series of molasse facies accompanied by volcanic activity. New detrital zircon data from this study, together with the distribution of sedimentary facies, indicate that the provenance of the Heitai Formation was mainly derived from magmatic rocks of Erguna-Xing’an and Songliao massifs and basement rocks of the Jiamusi Massif. In contrast, the provenance of the Zhenzishan Formation was derived from the basement rocks and the discernible arc of the Jiamusi Massif. The weighted mean 206Pb/238U ages for the youngest zircons indicate that the maximum depositional ages of the Heitai and Zhenzishan formations were estimated at ca. 375 Ma and ca. 305 Ma, respectively. These data support, in the eastern Jiamusi Massif, a transition from a passive to an active continental margin occurred between the Late Devonian and late Carboniferous (375−305 Ma), which was likely related to subduction of the Mongol-Okhotsk Ocean (a part of Panthalassa), which is also an important tectonic transition event in the eastern margin of Eurasia.

Collision Timing and Provenance Shifts from the Late Oligocene to Middle Miocene in the Southeasternmost Zagros Orogen

Determining the timing of the initial continental collision is a fundamental step in accurately reconstructing the paleogeodynamic evolution of orogenic belts. This process necessitates a comprehensive integration of evidence gathered through various analytical techniques, both in the field and in the laboratory, to achieve a conclusive understanding. We here use comprehensive methods, including sandstone petrography, U-Pb dating, trace element and Hf isotopic compositions of the detrital zircon, in the Haji Abad (eastern Zagros Orogen) and the Shamil areas (west of the Minab-Zendan Fault) to constrain the timing of the initial collision between Arabia and Eurasia. Zircon U-Pb dating in the Haji Abad area reveals that detritus predominantly originates from the Arabia Pan-African basement (∼640 − 539 Ma, ƐHf (t): -10 to + 10) at the base of the Upper Oligocene-Lower Miocene Razak Formation. This is subsequently replaced up-section by detritus from Cenozoic and Mesozoic Eurasia magmatic-arc sources (~ 54 − 10 Ma, ƐHf (t): -2 to + 16; ~110 − 89 Ma, ƐHf (t): -2 to + 20, and ~ 175 − 163 Ma, ƐHf (t): -4 to + 10). In contrast, the Shamil area shows that detritus from the Pan-African Arabia basement remained dominant until the Early Miocene. The minimum age of continental collision is characterized by a significant change in provenance, transitioning from detritus sourced from the Arabia lower plate to that derived from the Eurasia upper plate. This transition is documented from the Late Oligocene in the Neyriz and Haji Abad areas along the Main Zagros Thrust, to the Middle Miocene (Langhian) in the Shamil area along the Minab-Zendan Fault.

Re-evaluating the tectonic affinity of Proterozoic crustal provinces in the Southwest USA: Detrital zircon evidence for a Laurentian source for the Yavapai and Mojave Provinces

Models for crustal growth commonly involve the accretion of dominantly juvenile crust to continental margins. However, tracking the provenance and tectonic affinity of dominantly juvenile crustal provinces is challenging. This difficulty is highlighted by uncertainty over whether the Yavapai and Mojave Provinces, part of the >1300-km-wide system of Proterozoic orogens in southwestern Laurentia, (1) have similar crustal and tectonic histories and (2) if they formed on or near Laurentian, Australian, or Antarctic cratons. Here, we contribute new large-n detrital zircon U-Pb geochronology and Sm-Nd whole-rock isotope geochemistry to help constrain the provenance of the Yavapai Province and address these broader questions. Yavapai Province metasedimentary rocks from central Colorado in the southwestern USA have abundant pre-1.80 Ga detrital zircon grains, with ca. 1.85 Ga, 2.30 Ga, and 2.50−2.70 Ga peaks, and variable amounts of 1.79−1.78 Ga grains. Evolved whole-rock Sm-Nd isotopic compositions from these rocks, including 2.36−2.08 Ga model ages, also suggest mixing between 1.79 Ga and 1.78 Ga Yavapai Province arcs and early Proterozoic to Archean sources. Nearly identical pre-1.8 Ga detrital and inherited zircon age distributions suggest that the Yavapai and Mojave Provinces formed on and/or incorporated similar material. The Trans-Hudson orogen, and to a slightly lesser extent the Penokean orogen, provide the closest matches to the pre-1.80 Ga material in the Yavapai and Mojave Provinces. This similarity, coupled with a weaker resemblance to Australian and Antarctic sources, support a Laurentian affinity for the Yavapai and Mojave Provinces. We envision Paleoproterozoic arc formation on both oceanic crust and material of Laurentian affinity and multiple phases of arc-back-arc genesis, closure, and accretionary tectonism along the long-lived margin of the supercontinent Columbia (Nuna).

The Triassic tectonic transition of the Northwestern margin of Ordos Basin, North China Craton

ABSTRACT The Northwestern margin of Ordos Basin (NWOB), which contains the Helanshan Tectonic Belt (HTB) and Northwestern margin of Ordos Basin Thrust Belt (NWOBTB), is situated in the northwest of the North China Craton (NCC). The Triassic sedimentary-tectonic transition of the NWOB provides crucial insights for revealing the tectonic evolution of the NCC. In this study, we have utilized a comprehensive dataset including the palaeocurrent orientations, sandstone modal composition, U-Pb age analysis of detrital zircons, and balanced cross-sections restorations, to clarify the Triassic sedimentary-tectonic evolution of NWOB. The southeast-directed palaeocurrent indicates the sediments were primarily derived from northwest. The composition of clastic material suggests diverse sources, including magmatic arc and continental blocks. Detrital zircons extracted from four sandstones yield five major LA-ICP-MS U-Pb age groups: 2600–2500 Ma, 2300–2200 Ma, 2000–1800 Ma, 500–400 Ma and 390–230 Ma. A comparison of these U-Pb age groups from the Triassic strata in the NWOBTB with the magmatic records in the Alxa Massif, the Qilian Orogenic Belt, and detrital zircons from pre-Triassic strata in the HTB reveals that the Triassic detritus in the NWOBTB was predominantly originated from the Alxa Massif. Furthermore, the absence of detrital zircons in NWOBTB that originated from the HTB suggests the HTB had not been uplifted until the Mid-Late Triassic and remained in a steady sedimentary environment with NWOBTB during this period. In addition, the E-W treading shortening structures, along with the angular unconformity between the Jurassic and the Upper Triassic in the HTB, indicate a phase of extensive N-S shortening occurred in the HTB in the end of the Triassic. Balanced cross-section restorations demonstrate the southern HTB experienced 27% shortening, while the middle HTB underwent 15% shortening. In contrast, the Jurassic strata are in parallel-unconformity with the Triassic strata in the NWOBTB. This suggests the NWOBTB was not significantly effected by the end Triassic N-S shortening deformation. These distinct deformations between the HTB and NWOBTB imply that there was a phase of dextral strike-slip displacement between the two regions in the end of the Triassic, which is related to the closure of Paleo Tethys Ocean.

Detrital zircon U–Pb geochronology of the Murree Formation, western Himalaya, Pakistan: provenance and tectonic implications for Himalayan exhumation

ABSTRACT The Murree Formation is the oldest continental sequence in the Himalayan foreland basin and holds significant information about the Himalayan exhumation following the India-Asia collision. This study explains the provenance of the Murree Formation using detrital zircon U-Pb geochronology supplemented with sandstone petrography to unravel the Himalayan exhumation in Pakistan. The sandstone provenance indicates the sediment was sourced from recycled orogen and suture belts, supporting a post-collisional origin. The source rocks, shown by the ternary plot (QpQnuQu), comprise plutonic and medium to high-rank metamorphic rocks prevalent in the Higher Himalaya (HH), Tethyan Himalayan (TH), and Lesser Himalaya (LH). The zircon ages are mainly ~ 1200–400 Ma, with two minor clusters (~1900–1400 Ma and ~ 2600–2300 Ma). This pattern is compatible with a Himalayan source mainly from the TH, HH, and partly from LH. Notably, the age populations < 200 Ma are in minor percentages, which indicates the hindrance from the Kohistan – Ladakh Arc (KLA) (Asian source) to the foreland basin due to the uplift of the TH and HH blocks. Combining the petrography and zircon U – Pb geochronology, a tectonic model is proposed, which suggests fold – thrust belt propagation to the south after the India – Asia collision. During the deposition of the Murree Formation in the foreland basin, TH and HH blocks were already uplifted in the western Himalaya, which provided major detritus. Along with this significant contribution, a minor contribution from a part of the LH is also suggested. This suggestion is based on the presence of Cambro – Ordovician detrital zircon ages, mainly from the plutonic source indicative of erosion of the Cambro – Ordovician granites and metamorphic rocks due to the initial phase of uplift along the Panjal fault.

Triassic contractional deformation and sedimentary response in the Helanshan fold–thrust belt, Northwest China: evidence from growth strata

ABSTRACT The Helanshan fold – thrust belt is located between the Alxa and Ordos blocks and has been a deformation area of tectonic activity since the Mesozoic. During the Mesozoic tectonic deformation, the Jurassic WNW – ESE-trending contraction transformed the Triassic NNE – SSW shortening. Field mapping and structural analysis reveal that the Middle Triassic Zhifang Formation in the northern wing of the Rujigou overturned anticline is characteristic of a growth strata, which is in response to SSW-NNE contraction. Detrital zircon U – Pb age spectra of the Middle Triassic Zhifang Formation show that the Triassic sedimentary materials originated from the North China Craton to the north, the Alxa block to the north, the Qilian orogenic belt to the south, and the Qinling orogenic belt to the south. The youngest age at the bottom of the growth strata is 282 ± 11 Ma, and the youngest age at the top is 291 ± 12 Ma, indicating that the strata maximum depositional age was later than the Permian, revealing that the youngest detrital zircon of the Middle Triassic Zhifang Formation is derived from the Rujigou overturned anticline, reflecting the characteristics of the reverse sedimentary sequence of detrital zircon and suggesting an interaction between structure and deposition. We propose that with the closure of the Paleo-Tethys Ocean, under the far-field response to the collision between the North China Craton and South China Craton, the Helanshan fold – thrust belt expanded northward and formed a northward protruding tectonic node that controlled the sedimentary process of the Triassic foreland basin.

Paleogeographic evolution of the western Taebaeksan Basin, Korea: constraints from provenance of late Carboniferous sediments

ABSTRACT A distinctive unconformity between Cambro-Ordovician and Permo-Carboniferous strata in North China and the Taebaeksan Basin (TB) in Korea has been regarded as key evidence supporting their tectonic affinity (the ‘Sino-Korean Block’). However, controversy continues over the palaeogeographic position of the western part of the TB prior to the North and South China collision. To resolve this issue, we focus on the basal units of the upper Palaeozoic sequence overlying the Cambro-Ordovician strata. Results show that these late Carboniferous sediments, the Gapsan and Yobong formations in the western TB and the Manhang Formation in the eastern TB are all highly similar in composition, suggesting a common provenance: sandstones mostly consist of quartz and (meta)sedimentary rock fragments and are virtually devoid of feldspar; mudrocks are extremely depleted in CaO and Na2O, while elemental ratios of immobile trace elements including rare earths are comparable to the recycled upper continental crust; detrital zircon ages are highly concentrated at 1.8–1.9 Ga and 310–340 Ma, whereas Meso- to Neoproterozoic ages are scarce. Coupled with the clear similarities in lithology, the collected data are in favour of the palaeogeographic views that the western and eastern TB were contiguous by the late Carboniferous.