Trilobite moulting behaviour has been extensively investigated. However, exuviae in eodiscid trilobites are poorly known. Here, we report two eodiscid trilobite specimens, Tsunyidiscus niutitangensis and Tsunyidiscus sp., showing Somersault configuration from the Niutitang Formation and Mingxinsi Formation of South China, respectively (Cambrian Series 2, Stage 3). The arrangements of the exoskeletons indicate that the two specimens are the slightly disturbed and undisturbed exuviae. The impression of the lower cephalic unit (LCU) displays the rostral plate in Tsunyidiscus niutitangensis. The exuviae showing the LCU inverted anteriorly under the trunk. The opening of the facial and rostral sutures would have allowed the emergence of the post-ecdysial trilobite with the partial enrolment of exoskeleton. Moreover, our discovery indicates a Somersault configuration which employed the facial and rostral sutures to create an anterior exuvial gape that also exists in eodiscid trilobites besides redlichiid trilobites, corynexochid trilobites and ptychopariid trilobites during the Cambrian.

Aspergillosis is a rising concern worldwide; however, its prevalence is not well documented in China. This retrospective study determined Aspergillus’s epidemiology and antifungal susceptibilities at Meizhou People’s Hospital, South China. From 2017 to 2022, the demographic, clinical, and laboratory data about aspergillosis were collected from the hospital’s records and analysed using descriptive statistics, chi-square test, and ANOVA. Of 474 aspergillosis cases, A. fumigatus (75.32%) was the most common, followed by A. niger (9.92%), A. flavus (8.86%), and A. terreus (5.91%). A 5.94-fold increase in aspergillosis occurred during the study duration, with the highest cases reported from the intensive care unit (52.74%) – chronic pulmonary aspergillosis (79.1%) and isolated from sputum (62.93%). Only 38 (8.02%) patients used immunosuppressant drugs, while gastroenteritis (5.7%), haematologic malignancy (4.22%), and cardiovascular disease (4.22%) were the most prevalent underlying illnesses. In A. fumigatus, the wild-type (WT) isolates against amphotericin B (99.1%) were higher than triazoles (97–98%), whereas, in non-fumigatus Aspergillus species, the triazole (95–100%) WT proportion was greater than amphotericin B (91–95%). Additionally, there were significantly fewer WT A. fumigatus isolates for itraconazole and posaconazole in outpatients than inpatients. These findings may aid in better understanding and management of aspergillosis in the region.

The coastal region of Guangdong Province, China, is characterized by well-developed dyke swarms. The dykes with widths of decimetres to metres and lengths of tens of metres occur along straight and planar fractures cutting granites or volcanic rocks with Jurassic to Early Cretaceous ages. They show steep attitudes with strikes varying from NNW to NNE and from NE to SE, consistent with a stress regime transition from E–W to N–S extension. Major-element analysis on representative dyke samples reveals a composition range from basaltic to andesitic with a few dacitic outliers. Trace elements of most samples show notable Nb–Ta negative anomalies and Pb positive anomalies on the primitive mantle normalized spidergrams, characteristic of arc-related rocks. Among these, several dacite samples show notable fractionated medium rare earth elements and heavy rare earth elements and high Sr/Y (47–74) and La/Yb (15–21) ratios indicative of adakitic affinity. A few samples lack anomalies in Nb and Ta and have primitive trace-element ratios (e.g. Nb/La and Sr/Nd) or initial ϵNd values resembling ocean island basalt-like rocks. Rare earth element distribution patterns of all samples are right inclined and generally absent of Eu anomalies, which together with other trace-element indexes indicate an origin from heterogeneous mantle sources with depths below the stability field of plagioclase. Radiogenic isotopes, especially those of Nd and Sr (or Nd–Pb), define an array extended from the depleted to enriched mantle (EMII) provenance. LA-ICP-MS dating of zircon obtains ages between 110 and 70 Ma indicating emplacement of these dykes in latest Early to Late Cretaceous time, a time just before initiation of the South China Sea basin. In the context of regional geodynamics, it is proposed that these dykes were formed in a tectonic setting transiting from a Pacific-related back-arc to a passive continental margin pertaining to the development of the South China Sea basin.

Ediacaran cap dolostone atop Marinoan glacial deposits contains complex sedimentary structures with extremely negative δ13Ccarb values in close association with oscillations in palaeoclimatic and oceanographic proxy records. However, the precise geological, geochronological and geochemical context of the cap dolostone is not clarified, which hampers us from correctly interpreting the extremely negative δ13Ccarb values and their causal relationships with the Snowball Earth hypothesis. In this study, we conducted detailed in situ geochronological and geochemical analyses on the calcite within the cap dolostone from the Ediacaran Doushantuo Formation in South China in order to define its formation and relationship to the Snowball Earth hypothesis. Petrographic observations show that formation of dolomite pre-dates precipitation of calcite and pyrite, which pre-dates quartz cementation in the basal cap carbonate. Calcite cement within the cap dolostone yielded a U–Pb age of 636.5 ± 7.4/17.8 Ma (2σ, MSWD = 1.6, n = 36/40), which is within uncertainty of a published dolomite U–Pb age of 632 ± 17 Ma (recalculated as 629.3 ± 16.7/22.9 Ma). These age constraints negate the possibility that the calcite cement was formed by late Ediacaran or Cambrian hydrothermal activity. The rare earth element distribution patterns suggest a dominant seawater origin overprinted by subsequent early Ediacaran hydrothermal activity. The combined age, petrographic and geochemical data suggest oxidization of methane clathrates in response to complicated interplay between eustasy and isostatic rebound and hydrothermal fluids.

The South China Block is one of the largest continental blocks located on the East Asian continent. The early Palaeozoic Wuyi–Yunkai orogen of the South China Block (known as the Caledonian orogen in Europe) is a major orogenic belt in East Asia and represents the first episode of extensive crustal reworking since Neoproterozoic time. Although this orogen is key to deciphering the formation and evolution of the South China Block, details about the orogen remain poorly defined. The Songshutang and Wushitou ultramafic–mafic units in southern Jiangxi Province, South China, have 206Pb–238U ages of c. 437 Ma, suggesting a Silurian formation age. All the Songshutang and Wushitou ultramafic–mafic rocks show relatively flat chondrite-normalized rare earth element patterns, depletions in Nb, Ta, Zr, Hf and Ti, and low ϵNd(t) values from −9.12 to −5.49 with negative zircon ϵHf(t) values from −10.84 to −2.58, resembling a typical arc magma affinity. Geochemical and isotopic data indicate that the newly identified ultramafic–mafic rocks, along with the reported Silurian mafic rocks in South China, possibly originated from the similar partial melting of an ancient subducted slab, fluid/sediment and metasomatized lithospheric mantle with varying degrees of fractional crystallization. In conjunction with other records of magmatism and metamorphism in South China, a late-orogenic extensional event led to the melting of the sub-continental lithospheric mantle in Silurian time and generated ultramafic–mafic rocks with a limited distribution along the Wuyi–Yunkai orogen and widespread late-orogenic granitic plutons in the South China Block.

Radiodonts are a diverse clade of Lower Palaeozoic stem-group euarthropods that played a key role in the emergence of complex marine trophic webs. The latest addition to the group, Cambroraster falcatus, was recently described from the Wuliuan Burgess Shale, and is characterized by a unique horseshoe-shaped central carapace element. Here we report the discovery of Cambroraster sp. nov. A, a new species from the Cambrian Stage 3 Chengjiang Lagerstätte of South China. The new occurrence of Cambroraster demonstrates that some of the earliest known radiodonts had already evolved a highly derived carapace morphology adapted to an essentially eudemersal life as sediment foragers.

Permian–Triassic boundary (PTB) volcanic ash beds are widely distributed in South China and were proposed to have a connection with the PTB mass extinction and the assemblage of Pangea. However, their source and tectonic affinity have been highly debated. We present zircon U–Pb ages, trace-element and Hf isotopic data on three new-found PTB volcanic ash beds in the western Hubei area, South China. Laser ablation inductively coupled plasma mass spectrometry U–Pb dating of zircons yields ages of 252.2 ± 3.6 Ma, 251.6 ± 4.9 Ma and 250.4 ± 2.4 Ma for these three volcanic ash beds. Zircons of age c. 240–270 Ma zircons have negative εHf(t) values (–18.17 to –3.91) and Mesoproterozoic–Palaeoproterozoic two-stage Hf model ages (THf2) (1.33–2.23 Ga). Integrated with other PTB ash beds in South China, zircon trace-element signatures and Hf isotopes indicate that they were likely sourced from intermediate to felsic volcanic centres along the Simao–Indochina convergent continental margin. The Qinling convergent continental margin might be another possible source but needs further investigation. Our data support the model that strong convergent margin volcanism took place around South China during late Permian – Early Triassic time, especially in the Simao–Indochina active continental margin and possibly the Qinling active continental margin. These volcanisms overlap temporally with the PTB biocrisis triggered by the Siberian Large Igneous Province. In addition, our data argue that the South China Craton and the Simao–Indochina block had not been amalgamated with the main body of Pangea by late Permian – Early Triassic time.

While Chinese local governments remain extremely wary of workers’ collective actions, they do not always suppress them; sometimes, they tolerate such actions and even seek to placate workers. What accounts for these different government responses to workers’ collective actions? Based on a sample of over 1,491 collective action cases that took place in Guangdong between 2011 and 2016, we find that the types of demands raised by workers during collective actions affect how local governments respond. Local governments are likely to forcefully intervene in collective actions in which workers make defensive claims concerning issues of payment. In contrast, local governments are likely to use non-forceful approaches in response to actions in which workers make defensive claims regarding social security.

In response to a series of strikes in south China in 2010, a new model of collective bargaining has emerged, featuring what this article describes as “moderated mobilization.” Distinct from what is typically known as China's quadripartite industrial relations system, whereby workers are separated from the party-state, official trade unions and employers, this model shows workers and enterprise-level trade unions in collaboration with one another. According to our observations from 2012 to 2017, some enterprise unions have successfully mobilized workers throughout the collective bargaining process. These unions are democratically elected by workers and are relatively independent from the official authorities. At the same time, they have “moderated” such mobilization particularly to reduce labour militancy, given the political and institutional constraints within which they must work. The implication of this new model is significant. Although it might be far from solving the quadripartite dilemma, it has signalled an increase in local initiatives among enterprise unions – a previously neglected but pragmatically favourable channel for workers.

Around 5000 BC, affluent village communities emerged along the South China Coast. Although traditionally regarded as ancestors of Austronesian migrants, whose farming economies expanded into the Asia-Pacific region, the new synthesis presented here shows that these coastal groups actually lived as hunter-gatherers and fishers, with evidence of socio-cultural complexity. Around c. 3000–2500 BC, this ‘first layer’ of hunter-gatherers witnessed the arrival of a ‘second layer’, associated with rice farming and Austronesian assemblages. This new synthesis positions global coastlines as centres of socio-economic and political complexity, long-distance contact and technological advancement.

The Early Palaeozoic geology of the South China Craton (SCC) is characterized by an Early Palaeozoic intracontinental orogen with folded pre-Devonian strata and migmatites, MP/MT metamorphic rocks and Silurian post-orogenic peraluminous magmatic rocks in both the Yangtze and the Cathaysia blocks. In this contribution, we present new zircon U–Pb ages and Hf isotope data for detrital zircons from the Neoproterozoic to Silurian sedimentary sequences in the southeastern Yangtze Block. Samples from Neoproterozoic rocks generally display a major peak at 900–560 Ma, whereas samples from Lower Palaeozoic rocks are characterized by several broader peaks within the age ranges 600–410 Ma, 1100–780 Ma, 1.6–1.2 Ga and 2.8–2.5 Ga. Provenance analysis indicates that the 900–630 Ma detritus in Cryogenian to Ediacaran samples was derived from the Late Neoproterozoic igneous rocks in South China that acted as an internal source. The occurrence of 620–560 Ma detritus indicates the SE Yangtze was associated with Late Neoproterozoic arc volcanism along the north margin of East Gondwana. The change of provenance resulted in the deposition of 550–520 Ma and 1.1–0.9 Ga detrital zircons in the Cambrian–Ordovician sedimentary rocks. The εHf(t) values of these detrital zircons are similar to those of zircons from NW Australia–Antarctica and South India. This change of provenance in the Cambrian can be attributed to the intracontinental subduction between South China and South Qiangtang, and the convergence of India and Australia when East Gondwana finally amalgamated.

Detrital zircons are often used to constrain the maximum sedimentary age of strata and sedimentary provenance. This study aimed at reconstructing the Cryogenian palaeogeography of the Yangtze Domain based on U–Pb ages and Lu–Hf isotopic signatures of detrital zircons from sandstones in the southeastern part of the Yangtze Domain. U–Pb ages of the youngest detrital zircon grains from the Niuguping, Gucheng and Datangpo formations yielded average ages of 712±24 Ma, 679.2±6.2 Ma and 665.1±7.4 Ma, respectively, which are close to the depositional ages of their respective formations. An integrated study of detrital zircon Lu–Hf isotopes and U–Pb ages from three samples revealed six main peak ages in the samples from the Anhua section at c. 680 Ma, c. 780 Ma, c. 820 Ma, c. 940 Ma, c. 2000 Ma and c. 2500 Ma. The characteristics of the U–Pb ages and Hf isotopes indicate a link between the north and southeast margins of the Yangtze Domain as early as c. 680 Ma, and the provenance of the coeval sedimentary sequences in the SE Yangtze Domain was the South Qinling Block on the northern margin of the Yangtze Domain. The provenance analysis on the c. 680 Ma detritus composing upper Neoproterozoic strata in the Yangtze Domain revealed that the detritus was transported southward from South Qinling to the southeast margin of the Yangtze Domain through the Exi Strait, but was hindered by the Jiangnan Orogenic Belt.

The clay mineralogy and chemical composition of the white veins, red matrix and both Fe- and Mn-bearing nodules occurring in a laterite profile in Hubei, south China were investigated using X-ray diffraction, scanning electron microscopy equipped with an energy-dispersive spectrometer, and high-resolution transmission electron microscopy. The results show that the mineral components of the red matrix are mainly quartz, kaolinite, halloysite, goethite and minor illite, whereas the white net-like veins contain mostly quartz, kaolinite, halloysite, and illite. In the net-like horizon, the chemical index of alteration (CIA, the ratio of Al2O3/(Al2O3+CaO+K2O+Na2O)) and the TiO2/Al2O3 ratio are 89.8% and 0.021 for the white vein and 90.7% and 0.025 for the red matrix, respectively. Both white-vein and red-matrix components have similar TiO2/Al2O3 ratios, and are similar to the ratio 0.027 of the unaltered bedrock. The similarity in TiO2/Al2O3 values indicates that all three portions of the laterite soil share the same origin. Also, although the white-vein and red-matrix components differ in Fe2O3 abundance, the similar CIA values do imply similar degrees of alteration. The Fe-bearing and Mn-bearing nodules were produced by the local accumulation of Fe2O3 and MnO, respectively. Halloysite in the weathering profile occurs in two different morphologies, tubular and platy crystals. Tubular halloysite occurs both in the red matrix and the Fe-bearing nodule whereas platy halloysite occurs only in the white vein and Mn-bearing nodule assemblages. Crystallization of small tubular halloysite from Si and Al concretions in the red matrix is observed, indicating that the morphology of these crystals in the weathering environment is mainly controlled by Fe3+ cations, whereas platy halloysite may be derived from the hydration of kaolinite.

The Lower Devonian Posongchong Formation (Wenshan, Yunnan Province, southwestern China) consists of a series of continental deposits with an outstanding plant megafossil diversity. More than 20 years ago, this formation was interpreted as ‘Siegenian' (∼Pragian) in age based on palynology. However, such interpretation needs further evidence because of the known differences between the dispersed spore assemblages from South China and Euramerica/northwestern Gondwana. Here, we present new dispersed spore assemblages recently recovered from the Posongchong Formation. The isolated spore diversity is highly diverse, with 18 genera and 32 species. The recognised taxa include, among others, Ambitisporites avitus, Aneurospora conica, Aneurospora posongchongensis sp. nov., Aneurospora xujiachongensis, Apiculiretusispora plicata, Archaeozonotriletes chulus, Concentricosisporites agradabilis, Dibolisporites echinaceus, Emphanisporites rotatus, Gneudnaspora divellomedia, Latosporites ovalis, Retusotriletes triangulatus, Tetrahedraletes medinensis and Verrucosporites polygonalis, with Aneurospora and Retusotriletes being the most abundant forms. The known Posongchong palynoflora (previous spore data included) suggests that the Posongchong Formation assemblages can be correlated with the Pragian interval of the polygonalis–wetteldorfensis Oppel Zone (PoW). This age determination is supported by the presence of index species of PoW, such as Verrucosporites polygonalis, Dictyotriletes subgranifer and Camarozonotriletes parvus (sensu Steemans, 1989), the latter being known only from the Pragian of Belgium and Germany. Recent advances in the study of the marine faunas in the overlying sequences also indicate a Pragian age for the Posongchong Formation. This new investigation of the Posongchong palynoflora highlights differences of abundance at species level between the Gondwanan–Laurussian floras during the Early Devonian.

We report three Palaeozoic sedimentary successions in northeastern South China that display markedly different tectonostratigraphic characteristics: the Jiangshan section exhibits an angular unconformity between the Upper Ordovician and Carboniferous stratra; the Shuangming section exhibits a disconformity between the lower Silurian and Upper Devonian strata; and the Xinqiao section exhibits a disconformity between the upper Silurian and Upper Devonian strata. The Shuangming and Xinqiao sections are interpreted to represent the remnant Nanhua foreland basin, whereas the Jiangshan section is in the fold-and-thrust zone of the Wuyi-Yunkai orogen. The Lizhu-Changshan thrust fault in between is interpreted to be the frontal thrust and the boundary of the orogen. Detrital provenance analysis of the Ordovician–Devonian sandstones from the Shuangming and Xinqiao sections shows that the Ordovician–Silurian, mid- to late-orogenic sandstones contain dominantly 860–780 Ma zircon populations and subordinate 2.5 Ga, 1.89–1.78 Ga, 980–950 Ma, 630–540 Ma and 430 Ma populations, indicating nearby sources including the early Neoproterozoic Sibao orogen, inverted Neoproterozoic rift basins and related plutons, recycled Ediacaran–Cambrian strata and, increasing with time, exposed Cathaysia basement and minor syn- to late-orogenic plutonic intrusions. The Devonian post-orogenic sandstones exhibit a dominant 440 Ma population with minor 2.5 Ga, 1.89–1.78 Ga, 860–780 Ma and 630–540 Ma populations, suggesting a dominant contribution from now widely exposed, mid- to late-orogenic plutonic intrusions (with or without contributions from rare volcanism of similar ages) in a residual topographic high SE of the Lizhu-Changshan fault. This residual topographic high of the Wuyi-Yunkai orogen had completely perished by early Carboniferous time, c. 60Myr after the end of the orogenic event.

The Guadalupian mass extinction took place during the major global environmental changes during Phanerozoic time. Large-scale sea-level fluctuations and a negative shift of δ13C were associated with this crisis. However, the diagenetic or primary origin of the decreased δ13C across the Guadalupian–Lopingian (G–L) boundary and the potential causes for this biotic crisis are still being intensely debated. Integrated analyses, including detailed petrographic examination, identification of foraminifer and fusulinid genera, and analysis of carbonate δ13Ccarb and bulk δ13Corg across the G–L boundary were therefore carried out at Tianfengping, Hubei Province, South China. Our results show that: (1) some foraminifer and most fusulinid genera disappear in the upper Maokou Formation (upper Guadalupian); (2) the negative shift of δ13Ccarb in the uppermost Maokou Formation is of diagenetic origin, but the values of δ13Ccarb in the remainder of the Maokou Formation and in the Wuchiaping Formation represent a primary signal of coeval seawater; and (3) the bulk δ13Corg perturbation across the G–L boundary at Tianfengping is mainly controlled by organic matter (OM) source, that is, terrestrial OM contribution. We suggest that the δ13Ccarb negative shift in the lower Wuchiaping Formation (Wuchiapingian) compared to that in the lower–middle Maokou Formation (Capitanian) were probably caused by the re-oxidization of 12C-rich OM during regression. Global regression resulted in the negative shift of δ13Ccarb at the G–L boundary in South China and led to the loss of shallow-marine benthic habitat. Large-scale global regression is probably one of the main causes for this bio-crisis.

Non-biomineralizing Ediacaran macrofossils are rare in carbonate facies, but they offer valuable information about their three-dimensional internal anatomy and can broaden our view about their taphonomy and palaeoecology. In this study, we report a new Ediacaran fossil, Curviacus ediacaranus new genus and species, from bituminous limestone of the Shibantan Member of the Dengying Formation in the Yangtze Gorges area of South China. Curviacus is reconstructed as a benthic modular organism consisting of serially arranged and crescent-shaped chambers. The chambers are confined by chamber walls that are replicated by calcispars, and are filled by micritic sediments. Such modular body construction is broadly similar to the co-occurring Yangtziramulus zhangii and other Ediacaran modular fossils, such as Palaeopascichnus. The preservation style of Curviacus is similar to Yangtziramulus, although the phylogenetic affinities of both genera remain unresolved. The new fossil adds to the diversity of Ediacaran modular organisms.