Lithofacies and biostratigraphical analysis has enabled the establishment of a stratigraphic event framework for Ludfordian and Pridoli strata in south Wales and the Welsh Borderland. In SW Wales, the Golden Grove Axis acted as a structural hinge separating the shallow marine storm-influenced Cae’r mynach Seaway from a pediment surface above which Ludfordian colluvium (Abercyfor Formation) was deposited. The Axis seeded four NW-derived river-influenced delta progrades of Leintwardinian to early Pridoli age (Tilestones Formation). A NE-sourced early Pridoli wave-influenced delta deposited the Downton Castle Sandstone Formation (DCSF), coeval to the youngest Tilestones prograde, with a lateral interface existing between Mynydd Epynt and the Clun Forest area. Except for the Malverns area, the DCSF is no longer recognized south of the Neath Disturbance. Early Pridoli forced regression promoted widespread subaerial exposure north of the Neath Disturbance, with incision into tracts close to the Welsh Borderland Fault System. The basinward-shift in facies belts resulted in marine erosion and deposition of a phosphatic ravinement pebble lag. The wave-influenced Clifford’s Mesne Sandstone Formation delta subsequently seeded on the Gorsley Axis with tidally influenced Rushall Formation accumulating in a back-barrier setting. The Pwll-Mawr Formation records the easterly advance of coeval coastal deposits on the western side of the remnant Cae’r mynach Seaway. Behind migrating delta coastlines, green muds accumulated on coastal plains (Temeside Mudstone Formation) with better drained red dryland alluvium (Moor Cliffs Formation) charting expansion of Old Red Sandstone lithofacies. Mid-Pridoli incision preserves the Pont ar Llechau Formation estuarine valley fill.

Geodynamic models implying subduction of continental crust either consider this process happening during collision, when the continental margin of the lower plate attempts subduction, or in pre-collisional stages, when tectonic erosion of the upper plate or subduction of continental extensional allochthons drag continental crust in the subduction channel. In the Zagros orogen (W Iran), high-pressure rocks are known only from the Sanandaj-Sirjan Zone, NE of the Main Zagros Thrust. Here, eclogites of the North Shahrekord Metamorphic Complex suggest subduction of continental crust slices derived from the upper plate (Central Iran) during the onset of the Neo-Tethys subduction along the southern margin of Iran. Eclogites record a clockwise pressure-temperature-time path, with pre-eclogitic epidote-amphibolites-facies phase assemblages preserved in garnet cores, a high-pressure stage, and a subsequent retrogression at amphibolite-facies conditions. By means of forward thermodynamic modelling and 40Ar/39Ar geochronology, the peak metamorphism has been constrained at 1.9-2.1 GPa and 550-600 °C, in the 191-194 Ma time span. The following retrogression during exhumation lasted at least until 144 Ma. Our data suggest that the onset of the Neo-Tethys subduction traces back prior to 190 Ma, involving together with the Neo-Tethys oceanic lithosphere also slices of the upper plate continental crust scraped off by means of tectonic erosion processes.

The Chahmileh Pb–Zn deposit, located northwest of the Central Iran Zone, is a sediment-hosted Pb–Zn deposit in the ‘Yazd-Anarak Metallogenic Belt’. It is hosted in Middle Triassic carbonate rocks and is mainly controlled by NW-trending faults. The main ore minerals are galena and sphalerite with minor chalcopyrite, pyrite, and quartz, dolomite, along with minor calcite and baryte as gangue minerals. Cerussite, hemimorphite, wulfenite, mimetite, smithsonite, malachite and iron oxy-hydroxides are the main non-sulphide ore minerals. The main styles of mineralization are vein-veinlet, breccia, disseminated and replacement in association with silicification and dolomitization. Microthermometry of fluid inclusions in dolomite and quartz indicates that the ore precipitated from a warm to hot basin-derived saline fluid. Dolomite samples have δ13CVPDB and δ18OVSMOW values of −0.99 to +1.99‰ and +20.74 to +25.48‰, respectively, and are plotted in the marine carbonate rocks field. These isotopic values suggest that CO2 in the hydrothermal fluids mainly originated from marine carbonate rock. The δ34S values range from +6.3 to +8.2‰ for galena, +5.9 to +6.2‰ for sphalerite, +1.4 to +3.4‰ for chalcopyrite and +15.0 to +17.4‰ for bayite are compatible with a predominant thermochemical sulphate reduction process, and with sulphur sourced from Triassic seawater. Galena samples have a homogeneous Pb isotopic composition that is indicative of a continental crustal reservoir as the main source of lead and probably for the other ore metals. Based on geology, mineralogy, texture and fluid characteristics, the Chahmileh deposit is classified as a carbonate-hosted Mississippi Valley-type deposit.

Constraints on the tectonic setting of the upper Triassic to lower Jurassic in the Sverdrup Basin can be elucidated from detrital-zircon U-Pb ages. During the Triassic, there was a dual provenance system into sedimentary basins along the western and northern margins of Laurentia. One of the sediment sources was from an extra-basinal igneous source of Permian-Triassic zircon while the other source was recycled sediment eroded from older sedimentary basins. The Heiberg Formation/Group was deposited during a period of significant siliciclastic sedimentation into the basin from the upper Triassic to the lower Jurassic and comprises three members: Romulus, Fosheim and Remus. Previous work has interpreted that the Carboniferous-Permian-Triassic detrital zircon had stopped reaching the northern part of the Sverdrup Basin by deposition of the upper Heiberg Formation (lower Jurassic). New detrital-zircon age analyses from samples along the northern part of the basin spanning different horizons in the Heiberg Formation show that the typical extra-basinal signature, with abundant Carboniferous-Permian-Triassic ages, was no longer recorded during the initial deposition of the Fosheim Member during the latest Triassic. Previously published basin analysis from the Sverdrup Basin interprets syn-Jurassic extensional faults and so we relate the provenance change to the onset of extension. It is interpreted that the Sverdrup Basin transitioned from a basin that received sediment from a northern extra-basinal igneous source during deposition of the Romulus Member to an extensional basin by the deposition of the Fosheim Member in the latest Triassic, as the northern sediment source was interrupted by intervening extensional basins of the proto-Amerasia Basin.

The ∼407-myr-old Rhynie chert of Scotland contains exquisite body fossils of land plants, animals and microorganisms, which provide our earliest reasonably complete snapshot of a Phanerozoic terrestrial ecosystem. These fossils have been instrumental to our understanding of the ‘greening of the land’, a major transition in the history of the Earth–life system. Among the primary producers preserved in the chert are cyanobacteria, of which only a fraction have been formally described. Here, we report the occurrence of the colony-forming cyanobacterium Eoentophysalis in the Rhynie chert. To our knowledge, this represents the first bona fide record of Entophysalidaceae from any post-Cambrian fossil assemblage or any non-marine fossil assemblage of any age. The Rhynie Eoentophysalis appears remarkably similar in appearance both to modern marine and freshwater Entophysalis ssp. and to Eoentophysalis belcherensis, a shallow-marine fossil from the ∼2 Ga Belcher Group of Canada that is perhaps the oldest convincing cyanobacterium on record. Darkened cell envelopes in the Rhynie Eoentophysalis correspond well with both E. belcherensis and modern Entophysalis, whose cell envelopes often contain the photoprotective brown pigment scytonemin. The occurrence of Eoentophysalis in the Rhynie chert supports previous claims that the fossilisable traits of entophysalid cyanobacteria are evolutionarily static through geological time. These organisms may be such effective generalists that major changes in their environment – in this case, the transition to a fully non-marine habitat – have not imposed significant selection pressure on these traits.

Based on 30 high-resolution U-Th dating controls, we reconstruct stalagmite δ18O records from 45 to 15 thousand years ago (ka B.P., before AD 1950) from the Shizhu Cave, which is located in southwestern China under the influence of both the Indian Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM). By integrating with the other stalagmite δ18O records in Asia during the middle to late last glacial, our results reveal two main moisture trajectories: one from the Indian Ocean, through the Shizhu Cave towards central China, and the other from the Pacific Ocean to central and northern China. The systematic decrease of the average values of stalagmite δ18O records from oceans to inland China reveals a spatial pattern of water vapour fractionation and moisture trajectory during the middle to late last glacial. In contrast, the variation amplitude, which is defined as the departures apart from the background δ18O records during Heinrich stadials 1 to 4 (HS1–HS4), show an increasing trend from the coastal oceans to mid-latitude inland China, presenting a ‘coastal-inland’ pattern, which can be interpreted by the enhanced East Asian Winter Monsoon (EAWM) and the weakened EASM. More specifically, the enriched stalagmite δ18O records in the EASM region during HS1 to HS4 are caused by the decreased summer rainfall amount or/and the increased proportion of summer moisture resources from the Pacific Ocean. These new observations deepen our understanding of the complicated stalagmite δ18O records in the EASM region.

The Valpelline Series (Dent-Blanche Tectonic System, Western Italian Alps) is a sector of lower continental crust, which consists of Permian migmatitic metapelite with different mineral assemblages (i.e., garnet-, cordierite- and orthopyroxene-bearing), minor amphibolite and marble, intruded by aplite and pegmatite. Widespread melt production in metapelite and locally in amphibolite occurred during the development of the regional foliation. The P–T conditions during migmatisation, estimated using conventional geothermobarometers, range between 800–900 °C and 0.5–0.8 GPa, with a difference of up to ∼50 °C between cordierite- and orthopyroxene-bearing migmatites, the latter reaching higher temperatures. The Valpelline Series shows rock types, metamorphic assemblages, P–T conditions and published ages of high-temperature regional metamorphism like the archetypal lower crust section of the Ivrea-Verbano Zone in the Southern Western Alps. The latter likely represents an external portion of the same extending lower crust, at the onset of the Tethyan rifting due to lithospheric extension and asthenospheric rising.

The origins and age distribution of the Himalayan high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic rocks are critical for understanding the pre-Himalayan history. Although the protoliths to the UHP Tso Morari eclogites in Ladakh, NW Himalaya are believed to be the Permian Panjal volcanics, the geochronological evidence is absent. Here, we demonstrate that the protoliths of the UHP Tso Morari Complex formed in a continental rift setting at the Indian margin associated with the northern East Gondwana during the Early Paleozoic. Zircon U–Pb dates from eight gneisses and one garnet amphibolite indicate the Early Paleozoic bimodal magmatism of 493–476 Ma, which could be associated with the separation of South China from North India. Except for arc-related eclogites found in the Nidar ophiolite, the eclogites and amphibolites are rift-related, exhibiting enriched light rare earth elements and high concentrations of incompatible elements, along with evidence for crustal contamination. Our findings support the previously reported diversity in the sources and ages of the protoliths of the Himalayan HP–UHP metamorphic rocks along the orogen.

The Ediacaran–Cambrian (E-C) transition (∼542–517 Ma) witnessed the rapid evolution of Cambrian animals, which was accompanied by carbon cycling anomalies and a significant increase in the concentration of oxygen in Earth’s atmosphere. The mechanisms stimulating the evolution of complex eukaryotes, however, remain problematic, especially concerning the link between biological evolution and contemporaneous changes in the oceanic environment. In this study, integrated δ13Ccarb–δ13Corg–δ15N compositions were analysed from the YD-4 core samples to understand redox fluctuations and nitrogen cycling of the middle Yangtze Block across the E-C transition. Two negative δ13Ccarb excursions (N1 and N2) and a positive δ13Ccarb excursion (P1) are identified from the studied samples and are supposedly of primary origin. Constrained by of the U-Pb age, biolithology and pattern of isotopic variation, N1, P1 and N2 are comparable to the Basal Cambrian Carbon Isotope Excursion (BACE), Zhujiaqing Carbon Isotope Excursion (ZHUCE) and Shiyantou Carbon Isotope Excursion (SHICE). We interpreted the decreased δ15N values in this study as resulting from intensified atmospheric nitrogen fixation driven by enhanced denitrification associated with expanded marine anoxia, as well as partial ammonium assimilation, while increased δ15N values suggest weakened denitrification associated with an amplified oxic water mass. The temporal coincidence of N1 and N2, with two episodes of negative δ15N excursions, and of P1, with a positive δ15N excursion, suggests that variable oceanic redox conditions and nitrogen bioavailability may have influenced the evolution of the Cambrian eukaryote-dominated community.

Mafic dykes are typically emplaced through primary hydraulic fracturing of undeformed crust or may make use of pre-existing crustal inhomogeneities, representing the plumbing systems of a large igneous province. The Eastern Dharwar Craton has dense exposures of several generations of Paleoproterozoic mafic dyke swarms ranging from ca. 2.37 Ga to ca. 1.79 Ga. Herein, using anisotropy of magnetic susceptibility fabric data of mafic dykes and associated host granites, the emplacement systematics of the NW- to W-trending ca. 2.21 Ga Anantapur–Kunigal dyke swarm, displaying a radiating geometry, have been studied to understand magma flow dynamics. A low-angle relationship between the silicate and opaque fabrics and good correlation with magnetic lineation, identified via petrographic studies and shape preferred orientation analyses of multiple oriented thin sections, suggest a primary flow-related magnetic anisotropy for the studied dyke samples. The classic subparallel relationship between the trend of the dyke planes and magnetic fabric of the associated host granites suggests that the radiating geometry of the ca. 2.21 Ga dyke swarm was supported by a favourable pre-existing structural grain of the country rock. We interpret the magma for the studied dyke swarm was fed laterally from a distant plume. It was emplaced as laterally propagating primary dyke fractures as well as injected into the pre-existing subparallel crustal inhomogeneities. Corroborating all these inferences, a detailed emplacement model for ca. 2.21 Ga Anantapur–Kunigal dyke swarm is also proposed.

Various magmatisms during the subduction-collision process are crucial to reveal the long-term tectonic evolution of the eastern Central Asian Orogenic Belt. In this paper, we present major and trace elements of whole-rock, zircon U-Pb dating and Hf isotope of the Shanmen pluton. Results imply that the Shanmen pluton consists of quartz diorite and mylonitic granite, with zircon U-Pb ages of 263.7–259.6 Ma. The studied quartz diorite contains high Sr/Y (51.19–90.87) and (La/Yb)N (7.82–13.62) ratios, and belongs to adakitic rocks. Coupled with the positive εHf(t) values of +5.71 to +12.8 with no obvious Eu anomaly, we propose that quartz diorite is the product of the interaction between different degrees of slab melt and the overlying mantle wedge. In contrast, the mylonitic granite has lower MgO (0.28 wt% – 0.47 wt%) contents and positive εHf(t) values of +7.79 to +10.15, indicating an affinity with I-type granite originated by partial melting of the intermediate-basic lower crust. The geochemical characteristics and lithological assemblages, along with the Permian magmatic rocks in the Changchun-Kaiyuan area displaying arc rocks affinity, propose their formation is related to the southward subduction of the Paleo-Asian Ocean (PAO). Based on this study and previous evidence, we lean towards adopting a middle-late Permian slab break-off model, wherein the PAO did not close until the late Permian.

The traces left by earthquakes in the unlithified sediments, recorded as soft-sediment deformation structures (SSDS), are well reconstructed as palaeo-seismic signals, while the origin of SSDS, seismic vs. Aseismic, is challenging. The present study discusses the origin of SSDS and its implications on palaeoceanography and sediment architecture. In the Middle Jurassic succession of Spiti Himalayan region in India, the topmost part of the Ferruginous Oolitic Formation (FOF) consists of four layers of SSDS and is underlain by the lower member of the Spiti Formation (SF). The sedimentary facies analysis documents the palaeogeographic shift from the middle shelf (carbonate-shale repository: FOF) to the outer shelf (black shale: lower member of SF). The SSDS layers, exhibiting load casts, ball and pillow structures, indicate gravitational instability, while syn-sedimentary faults and insitu breccia are the results of brittle deformation. The dominance of storms in depositional sites often argues for a possible triggering agent for SSDS. Therefore, it was necessary to distinguish between seismic vs. aseismic triggering agents. The lateral continuity, vertical repetition, confinement of SSDS at the top part of FOF and sharp change of facies assemblage indicate seismicity-induced syn-sediment deformation, i.e. seismite. The transition from middle shelf to outer shelf at the onset of seismite indicates that seismic impact possibly caused the rapid subsidence, resulting in the palaeogeographic shift. The rapid transgression is recorded as carbonate-shale repository to anoxic black shale. This study highlights the importance of sedimentological analysis to distinguish the seismite and its implications on palaeogeographic evolution and sedimentary architecture.

The study presents detailed petrographical, geophysical, structural and geochemical data of the internal nappes zone to establish the deformational history, origin and tectonic setting and constrain the crustal growth and evolution of the active margin of the Dahomeyide belt. Two main lithological units, (i) deformed meta-granitoids (migmatites and gneisses) and (ii) undeformed granitoids, dominate the internal nappes zone. The granitoids are generally I-type, metaluminous to weakly peraluminous, low-K tholeiite to high-K calc-alkaline and of tonalite, granodiorite and granite affinity. The overall trace element patterns of the studied granitoids characterized by the enriched LILE and depleted HFS, with negative peaks of Nb-Ta, Sr, P and Ti, are indications of arc-related magmatism. Structural analysis reveals four deformation phases (D1-D4). D1 represents Northwest-Southeast (NW-SE) Pan African shortening associated with a continent-continent collision, resulting in westward nappe stacking. Progressive NW-SE shortening resulted in D2 and D3 top-to-the-NW dextral and sinistral thrusting events during the Pan-African orogeny. D4 is an extensional event likely associated with the orogenic collapse phase. The gneisses and migmatites, with dominant axial planar foliations, point to their formation in a collisional setting or influence by the Pan-African collisional processes. Continental-arc signatures in these rocks imply continental subduction during their protolith formation. The intrusive granitoid and pegmatite are undeformed, meaning late- to post-orogenic emplacement. These findings suggest that the internal nappes zone archived the subduction-collision and post-collisional phase of the Pan-African orogeny and recorded large-scale migmatization and granitoid emplacement due to partial melting of thickened lower crust between Mid-Cryogenian and late Ediacaran.

Field evidence from the northern Cotentin Peninsula and regional data are used to construct a tectono-stratigraphic model for the Ordovician which characterizes basin development in the North Armorican Massif. In La Hague, 15 m of transgressive marine sandstone belongs to the Dapingian age Grès Armoricain Formation which onlaps lower Cambrian, rift-fill deposits via an unconformity. Approximately 450 m of overlying Darriwilian strata are dominated by shallow marine sandstone showing hummocky cross-stratification with subordinate shales containing trace and body fossils. Together, these facies support an interpretation of offshore shallow marine strata overlying a break-up unconformity. Regional analysis indicates the time gap at the unconformity is 20–40 Ma and formed from crustal upwarping, which was greatest in the north of the Armorican Massif. Dapingian strata (Grès Armoricain) thins irregularly to the north (0–94 m), interpreted to reflect passive onlap onto residual relief associated with the uplift and the initiation of thermal subsidence on the margin. The succeeding Darriwilian strata (Schistes de Beaumont to Grès de May) conversely display a steady thickening (161–623 m) to the north, the stratal patterns suggesting that from the Darriwilian onwards, the ocean basin to the north was firmly established as the main locus of subsidence on the continental margin.

The congruence between rock quantity and biodiversity through the Phanerozoic has long been acknowledged. Rock record bias and common cause are the most discussed hypotheses: the former emphasizes that the changes in diversity through time fully reflect rock availability; the latter posits that the correlation between rock and fossil records is driven by a common cause, such as sea-level changes. Here, we use the Geobiodiversity Database (GBDB), a large compilation of the rock and fossil records, to test the rock bias hypothesis. In contrast to other databases on fossil occurrences, the section-based GBDB also records unfossiliferous units. Our multiple regression analysis shows that 85% of the variation in sampled diversity can be attributed to the rock record, meaning that major peaks and drops in observed diversity are mainly due to the rock record. Our results support a strong covariation between the number of unfossiliferous units and sampled diversity, indicating a genuine rock bias that arose from sampling effort that is independent of fossil content. This provides a compelling argument that the rock record bias is more prominent than common cause in explaining large-scale variations in sampled diversity. Our study suggests that (1) no single proxy can fully represent rock record bias in predicting biodiversity, (2) rock bias strongly governs sampled diversity in both marine and terrestrial communities, and (3) unfossiliferous strata contain critical information in predicting diversity of marine and terrestrial animals.

Typical ophiolitic rock assemblages such as siliciclastic rocks, basalts and gabbros, together with the subduction-related intermediate-acidic intrusive rocks, are newly discovered in the Tongjiang-Fuyuan area of the Heilongjiang Provence, NE China. To determine the formation age and genesis of the mafic rocks (basalts and gabbros) and intermediate-acidic intrusive rocks (granodiorites) in the area, as well as their geodynamic settings, the whole-rock geochemical analysis and zircon LA-ICP-MS U-Pb dating were carried out. Zircon U-Pb results suggest that the granodiorites are 93–95 Ma and gabbro is 95 Ma, respectively. Geochemical results show that the gabbros and basalts exhibit characteristics of ocean island basalt (OIB) affinity and are typically related to having originated from mantle plumes. While the granodiorites show the nature of the island-arc magmatic rocks and may originate from the lower crust. Based on the coeval igneous rock associations and regional tectonic evolution, we conclude that the late Cretaceous magmatic rocks in the Tongjiang-Fuyuan area are the product of continuous subduction of the Palaeo-Pacific plate and reflect the subduction rollback process of the Palaeo-Pacific plate.

High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma (Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma (Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma (Kiskinella cristata Zone) and 506.25 ± 0.07 Ma (Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possible Oryctocephalus indicus-plexus, invariable dysoxic lithofacies control of O. indicus and diachronous occurrence of O. indicus in temporally distinct δ 13C chemozones in South China and SW Laurentia. The lowest occurrence of O. indicus assemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6.

The concept of superposed fracture networks consisting of different generations, and often types, of fractures that have developed sequentially is discussed. Superposed networks can consist of different types of extension or shear fractures, and each fracture may abut, cross or follow (reactivate) earlier fractures. An example of a superposed fracture network in Liassic limestones in Somerset, UK, is presented, which comprises two sets of veins and a later joint network. The veins develop as damage zones around faults, with veins of the later set crossing or trailing along the earlier set. The later joints either cross-cut the earlier veins or reactivate them, the latter being common for the thicker (more than about 5 mm) veins. The veins and joint networks have markedly different geometries and topologies. The veins are spatially clustered and are typically dominated by I-nodes, while the joints are more evenly distributed and tend to be dominated by Y-nodes. The combined network of veins and joints at Lilstock is dominated by X-nodes because so many joints cross-cut the earlier veins. Understanding the development of superposed fracture networks leads to better understanding of the kinematic, mechanical, tectonic and fluid flow history of rocks.

Sedimentary rocks exposed at Dob’s Linn, Scotland, have significantly influenced our understanding of how life evolved over the Ordovician to Early Silurian. The current interpreted chronostratigraphic boundary between the Ordovician and Silurian periods is a Global Boundary Stratotype Section and Point (GSSP), calibrated to 443.8 ± 1.5 Ma (Hirnatian–Rhuddanian age), based on biostratigraphic markers, radioisotopic dates and statistical modelling. However, challenges arise due to tectonic disturbances, complex correlation issues and the lack of systematic dating in Ordovician–Silurian stratigraphic sections. Here, hundreds of zircon grains from three metabentonite ash horizons were dated using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). A subset of the grains were re-analyzed using Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry (CA-ID-TIMS). We present a high-precision CA-ID-TIMS 238U-206Pb weighted mean date of 440.44 ± 0.55/0.56/0.72 Ma (±analytical/with tracer/with U-decay constant) for the Coronagraptus cyphus biozone. However, the study reports younger, and in certain cases, older LA-ICP-MS zircon dates within the Coronagraptus cyphus, Akidograptus ascensus and Dicellograptus anceps zones, suspected as being influenced by Pb loss and LA-ICP-MS matrix mismatch. The study reports concerns about the suitability of Dob’s Linn as a GSSP section and examines various LA-ICP-MS maximum depositional age (MDA) approaches, suggesting the use of the TuffZirc date and the youngest mode weighted mean (YMWM) as suitable MDA calculations consistent with CA-ID-TIMS results.

The Jinying gold deposit is located in southern Jilin Province in northeast China and is representative of the large Early Cretaceous gold deposits in this area. To better understand ore genesis of this deposit, a multi-isotope integrated analysis of U–Pb–Rb–Sr–He–Ar–S has been carried out. Laser ablation inductively coupled plasma–mass spectrometry (LA–ICP–MS) dating of zircons from the granodiorite porphyry and dioritic porphyrite in the study area yields ages of 172.1 ± 1.2 Ma and 122.5 ± 0.8 Ma, suggesting that corresponding intrusion occurred in the Middle Jurassic and the Early Cretaceous. Rb–Sr dating of the pyrite yields an isochron age of 120 ± 3 Ma, suggesting that gold mineralization occurred in the Early Cretaceous. The fluid inclusions in pyrite yield 3He/4He ratios clustered within a small range from 0.08 to 0.13 Ra, 40Ar/36Ar ratios between 331.6 and 351.3, and mantle He in the range of 1.0–1.6%, indicating that the ore-forming fluids originated from a mixed crustal and mantle source. The in situ S isotopic values of pyrite vary between + 0.1 ‰ and + 2.8 ‰, suggesting that the ore-related sulphur came from the deep magmatic source. Combined with the geological history of the study area, it can be concluded that the gold mineralization was possibly related to the extensional setting associated with the rollback of the Palaeo-Pacific Plate.