Continental China Research Articles

Formation and Preservation conditions of ultra-deep (>6000 m) hydrocarbon systems

For 40 years, the concept of petroleum systems has been well developed and a considerable amount of actual data has been accumulated. However, with the beginning of the development of ultra-large depths (more than 6000 m, although nowadays this boundary has been lowered to 8000 m) it became clear that many processes proceed somewhat differently, and some a priori assumptions cease to be relevant. The article deals with the peculiarities of formation and conditions of preservation of petroleum systems when diving to ultra-large depths. Special attention is paid to numerous examples of HC detection in the liquid phase accumulated over the last decades, when the upper ‘classical’ threshold of formation temperatures, at which, as it was supposed, the transformation of liquid HC into gaseous should occur. Examples of studies of ultra-deep sections, first, well data, considered in the article, allow us to constantly revise upward the maximum temperatures in the pools, leading to oil destruction, previously estimated rather conservatively. This, in turn, causes reassessment of HC potential of many basins. At the same time, the volume of reserves of both oil and gas in ultra-deep sections is constantly increasing, especially in China, where vast experience of direct continental projects has been accumulated. At the same time, there are limited opportunities to prepare any practical recommendations directly, and the development of methods for forecasting such accumulations requires further significant efforts. It can be confidently assumed that the upper limit of the so-called ultra-deep will fall significantly below 8000 m, as the data show that geological constraints are significantly decreasing, technological solutions are continuously emerging, and their costs are steadily decreasing. The development of ultra-deep projects as an alternative to the so-called ‘shale’ projects will inevitably lead to an increase in their efficiency in developing oil and gas deposits, which are not perceived as such today. The article considers examples of ultra-deep hydrocarbon systems in the basins of continental China (Tarim, Dzungarian and Sichuan) and the Gulf of Mexico (Perdido folded zone).

Arsenic Reduces Methane Emissions from Paddy Soils: Insights from Continental Investigation and Laboratory Incubations.

Arsenic (As) contamination and methane (CH4) emissions co-occur in rice paddies. However, how As impacts CH4 production, oxidation, and emission dynamics is unknown. Here, we investigated the abundances and activities of CH4-cycling microbes from 132 paddy soils with different As concentrations across continental China using metagenomics and the reverse transcription polymerase chain reaction. Our results revealed that As was a crucial factor affecting the abundance and distribution patterns of the mcrA gene, which is responsible for CH4 production and anaerobic CH4 oxidation. Laboratory incubation experiments showed that adding 30 mg kg-1 arsenate increased 13CO2 production by 10-fold, ultimately decreasing CH4 emissions by 68.5%. The inhibition of CH4 emissions by As was induced through three aspects: (1) the toxicity of As decreased the abundance and activity of the methanogens; (2) the adaptability and response of methanotrophs to As is beneficial for CH4 oxidation under As stress; and (3) the more robust arsenate reduction would anaerobically consume more CH4 in paddies. Additionally, significant positive correlations were observed between arsC and pmoA gene abundance in both the observational study and incubation experiment. These findings enhance our understanding of the mechanisms underlying the interactions between As and CH4 cycling in soils.

CSRM‐1.0: A China Seismological Reference Model

AbstractHigh‐resolution seismic model is crucial for advancing our understandings on geological processes and enhancing seismic hazard mitigation programs. We construct a high‐resolution China Seismological Reference Model (CSRM‐1.0) in the top 100 km of the crust and uppermost mantle in continental China following a top‐down construction process. The employed seismic constraints include P‐wave polarization angle from tele‐seismic event, short‐period Rayleigh wave ellipticity from ambient noise, long‐period Rayleigh wave ellipticity from earthquake data, receiver function, empirical Green's function from ambient noise, Rayleigh wave phase/group velocity dispersion curves from regional earthquakes, and Pn‐wave travel time extracted from seismic data of 4,435 stations. CSRM‐1.0 has a spatial crustal resolution of ∼60 km beneath the north‐south seismic belt and trans‐North China orogen regions and ∼120 km beneath the rest of continental China, and a spatial mantle resolution of ∼300 km. CSRM‐1.0 exhibits prominent velocity heterogeneities in the crust and uppermost mantle and an eastward thinning of the crust, geographically correlating with geological settings. CSRM‐1.0 improvements include accurate estimation of shallow seismic structure, increased spatial resolution and improved model accuracy. Crustal composition inferred from CSRM‐1.0 exhibits a general transition from a felsic upper crust to a mafic lower crust. Mafic rocks in the lower crust are found predominantly along inter‐block boundaries and sporadically within the interiors of blocks, likely resulted from preferential inter‐block intrusions of magmas related to various oceanic plate subductions and the Emeishan mantle plume. This study contributes seismic constraints and CSRM‐1.0 to the CSRM product center (http://chinageorefmodel.org) as a backbone open‐access geophysical cyberinfrastructure.

Confirming the occurrence of two fiddler crabs, Tubuca dussumieri (H. Milne Edwards, 1852) and T. coarctata (H. Milne Edwards, 1852) (Crustacea: Decapoda: Ocypodidae), in Hong Kong by DNA barcoding and morphology

The Indo-West Pacific region has a rich fiddler crab fauna. In East Asia, some species of fiddler crabs, such as Tubuca coarctata (H. Milne Edwards, 1852) and T. dussumieri (H. Milne Edwards, 1852), are considered insular, being present in the Philippines, Taiwan, and Ryukyus, but with no consistent record on continental China. Although T. dussumieri has been previously recorded in continental China, these records were considered dubious or misidentified. The nature of the Kuroshio Current and the colder waters of the China Coastal Current, compared to the currents along the eastern coasts of the Philippines and Taiwan, are considered barriers to the entrance of larvae of these species into the region. Nonetheless, using the cytochrome oxidase subunit I (COI) gene and morphological evidence, we present the first record of T. coarctata and show the presence of a T. dussumieri population in Hong Kong SAR, China. We hypothesize that the newly found T. coarctata in Hong Kong may be related to water temperature increases due to anthropogenic climate change, which allows its larvae to survive in this region and develop into adult crabs. Furthermore, our findings corroborate previous records of T. dussumieri in continental China. The restricted distribution of T. dussumieri in China and the smaller size of individuals, however, may indicate suboptimal habitats for arriving larvae. The limited presence of the two crabs on Chinese shores indicates that the intense coastal development in the country, such as in Hong Kong, may destroy suitable habitats and render these species susceptible to local extinction.

Quantifying the extremity of 2022 Chinese Yangtze River Valley daily hot extreme: fixed or moving baseline matters

In 2022, an extreme heatwave struck the Yangtze River Valley (YRV) of China. Existing studies have highlighted its record-breaking magnitude by comparison with historical records using a fixed baseline. However, the quantification of extremity relies on the choice of baseline. While using fixed baseline allows us to understand the changes in extremes with the background warming, the use of moving baseline quantifies the extremity relative to recent climatology, and thus, takes into account the societal adaptation capability to global warming. Here, we revisit the 2022 heatwave in China and examine the extremity of daily hot extreme by comparing the two methods. Using a fixed baseline, daily hot extremes occurred in 2022 in the upper and middle reaches of YRV broke records since 1971. Nevertheless, using a moving baseline, daily hot extremes broke records only in the upper reaches (Sichuan Basin). In addition, it is not the most extreme event (measured by standard deviation (SD) anomalies), as China has experienced ∼13 more extreme events since 1971. The future projections show that, when using fixed baseline, 2022 Sichuan basin like extreme will occur every 2–12 years in 2081–2100 period under high-emissions scenarios, and will sweep China. Approximately 2%–25% of continental China will experience daily hot extreme with magnitude exceeding 5 SDs. Nevertheless, the projected changes based on moving climatology are weak, indicating that if we take measures to enhance our adaptability to background warming, the risks associated with hot extremes would be reduced in China.

Phylogeny and evolutionary history of Mavropanorpa n. gen. (Mecoptera: Panorpidae)

Mavropanorpa n. gen. is an Asian genus of scorpionflies with about 17 species, evidenced as monophyletic mainly because of the crossing of its thin subsidia (accessorial structures of the aedeagus). The genus diversified in continental east Asia before one species reached Japan, founding an evolutionary branch including Mavropanorpa japonica (Thunberg, 1784). The sister species of japonica migrated back to continental China and developed into today's M. kellogi. Lack of a medigynial apodeme in female M. japonica, lewisi and close allies is not plesiomorphic, but a result of reduction. The same holds for the shape of the subsidia and the lack of their crossing in M. japonica and M. kellogi, for which there is a pre-stage in M. nipponensis. Mavropanorpa and the type species of Panorpa, P. communis are compared with each other. A new genus name (Calliopanorpa) is also proposed for Panorpa takenouchii Miyaké, 1908 which is only superficially similar to Mavropanorpa. – Some morphological structures are renamed to avoid confusion with terminology in other insect groups or because unjustified homology might be inferred.

A Method for Determining Target Areas of Hot Dry Rock Resources: A Case Study in Continental China

Geothermal resources have been recognized as important sources of clean renewable energy. The exploration, development, and utilization of geothermal resources, especially hot dry rock (HDR) resources, are highly important for achieving peak carbon and carbon neutrality. However, there is no comprehensive evaluation method for determining HDR target areas, and the evaluation scale and application disciplines are relatively simplistic. In this paper, we sought to optimize the identification of HDR target areas through a multiscale and multidisciplinary method and formed a set of generalized and demonstrative processes to guide the exploration of HDR resources. Through practical application to the Gonghe Basin and the Zhangzhou Basin, it was found that the comprehensive geothermal conditions of the Gonghe Basin are superior to those of the Zhangzhou Basin, and the geothermal reservoir depth, geothermal reservoir temperature, geothermal gradient, and heat flow are the four most important factors affecting hot dry rock geothermal resources. Using this method, the prioritization of target areas changes from a qualitative study to a quantitative and semiquantitative study, increasing the specificity and reliability of the decision-making process.

The geopolitics of queer archives: Contested Chineseness and queer Sinophone affiliations between Hong Kong and Taiwan

Hong Kong and Taiwan, two Sinophone societies peripheral to continental China, have divergent colonial pasts and distinct cultures. Yet, their fates have been increasingly intertwined since the rise of China in the global economy. We propose the geopolitics of queer archives to trace minor–minor exchanges of queer knowledge and activism that are neither officially recognized by the state nor mapped into mainstream discussions of international relations. Through a conjunctural analysis of queer scholarship in Hong Kong and Taiwan since the 1980s, we contest the notion of Chineseness in shaping the knowledge of queer sexualities and argue that a wholesale recycling of postcolonial critique on these two societies’ resistance to China risk reproducing US-centrism.

Lithospheric Conductivity Structure in the Middle Segment of the Jiangnan Orogenic Belt: Insights into Neoproterozoic Tectonic–Magmatic Processes

Abstract The Jiangnan Orogenic Belt (JOB) evolved from the Yangtze and Cathaysia blocks through multi-stage oceanic-continental subduction, collisional orogeny, and intracontinental deformation, which is an important region to study the formation and evolution of the South China Continent (SCC). Magnetotelluric soundings were collected along a 520-km-long northwest (NW)-trending profile across the middle segment of the JOB to explore the possible remnants of ancient tectonic–magmatic processes beneath the central SCC by combining with the satellite gravity and magnetic data. The resistivity model reveals that the crust in the middle segment of the JOB and its adjacent area is characterized by high resistivity anomalies, while the uppermost mantle is characterized as medium resistivity anomalies and separated by several subvertical, lithospheric-scale conductors. Two trans-crust anomalies of high conductivity and low density beneath the Jiujiang–Shitai Buried fault (JSBF) and Jiangshan–Shaoxing fault (JSF) extend south-eastward to the lithosphere, which are attributed to the NW and southeast boundaries of the middle segment of the JOB. The imaged NW-trending of JSF reflects the tectonic process of the JOB subducting under the Cathaysia Block. Two lower-crustal conductors also imaged beneath the Jiuling area are interpreted as the partial melting of the lower crust, which may be related to the deep southeast subduction of the Paleo-south China Ocean during 970 to 860 Ma. In addition, the trans-lithosphere high conductivity adjacent to the ancient collisional zone of the Jinning period II (ACZII) is probably related to the asthenosphere upwelling caused by the soft collision between the Yangtze and Cathaysia Blocks, which triggered the contemporaneous magmatism in the Jiuling area. This work provides a new insight into the lithospheric evolution in SCC during the Neoproterozoic.

Evaluation of ERA5, ERA5-Land, GLDAS-2.1, and GLEAM potential evapotranspiration data over mainland China

Study regionChina. Study focusAccurate estimation of potential evapotranspiration (PET) is essential for understanding climate change. Using ground-based pan evaporation measurements over continental China, the monthly scale PET data during 2000–2017 of ERA5, ERA5-Land, GLDAS-2.1/Noah, and GLEAM V3.8a are evaluated, from the perspectives of their consistency in spatiotemporal variation, and performance measures. Factors controlling the data quality of the four datasets are investigated from the perspective of their PET calculation models and meteorologically input data. New hydrological insights for the regionPETERA5 performs the best in mainland China among four gridded PET datasets with higher correlation coefficients (r) and smaller biases, which can well capture the temporal variation of Epan. The outstanding performance of PETERA5 in China mainly results from the utilization of the Penman-Monteith (P-M) equation which performs the best among several competing formulas for PET computation, as well as its better meteorological inputs for computing PET than other datasets. Although the PETERA5-Land is a replay of the land component of the ERA5 climate reanalysis, it exhibits substantial overestimation of PET values and temporal trends, particularly in coastal areas of Southern China and the eastern side of Northeastern China, mainly caused by the overestimation of its net radiation. The PETGLDAS shows significant overestimation, partly due to its overestimation of wind speed, but mostly due to its modified P-M equation with its parameterization of land surface conditions for computing PETGLDAS. The PETGLEAM underestimated PET generally mainly due to the joint effect of the use of the Priestley-Taylor equation with small P-T parameter α, and the underestimation of the net radiation input from ERA-Interim, especially in Northwest and Qinghai Tibet.

Diverse Late Triassic arc magmatism and porphyry Cu deposits in the southeastern Tibetan Plateau: Related to slab tear along a subducting passive margin?

The subduction of the ocean–continent transition (OCT) zone on a passive margin has received limited attention, despite its significant impact on tectono-magmatic processes. This study focuses on the Late Triassic basalts and andesites in the southeastern Tibetan Plateau, where the Yushu-Yidun Arc belt intersects the Longmen Shan Fault system. The goal is to understand the interplay between these linear systems. The basalts exhibit trace element and isotopic signatures resembling those of within-plate enriched mid-ocean ridge basalts or ocean island basalts (EOBs), such as positive NbTa anomalies, high Nb/Th (7.72 to 10.3) and εNd(t) (+2.23 to +6.34) values, and low La/Sm values (2.69 to 4.05), suggesting an asthenospheric mantle source. The contemporaneous andesites display typical arc-like geochemical characteristics (e.g., enrichment in Ba, Th, and U but depletion in Nb, Ta, and Ti), with negative εNd(t) values (−2.41 to −1.08), indicating a mantle wedge source affected by subducted components. Geological evidence indicates that the Longmen Shan Fault zone, previously defined by its magmatic rocks, was an active OCT belt during the Late Triassic, separating the South China Continent from the Garze–Litang Ocean. Consequently, we propose a model suggesting the tearing of a subducted oceanic slab from the continental lithosphere within the OCT belt under the southernmost segment of the Yushu–Yidun Arc belt, driven by strong slab pull in the Garze–Litang Ocean subduction zone. This model effectively explains the intriguing geology of the Songpan–Garze–Hoh Xil Terrane, in which Late Triassic EOBs and normal arc-related igneous rocks coexist and are accompanied by abundant slab-derived mineralized porphyries. Our findings have global implications for investigating geochemically diverse magmatism and associated mineralization on passive continental margins.

Evolution of Cenozoic sedimentary architecture in Central and Southern South China Sea basins

The Central and Southern South China Sea (CSSCS) has a complex tectonic dynamic background and abundant oil and gas resources, which has always been a hot topic of academic and industrial attention. However, systematic analyses are still lacking regarding its sediment filling structure and evolution, mostly due to limited borehole penetration and poor quality of seismic reflection data for deeply buried sequences. No consensus has been reached yet on the sedimentary infilling processes, which impeded the reconstruction of the palaeogeography of Southeast Asia and the oil-and-gas exploration undertakings. Here, we illustrate the Cenozoic sedimentary evolution of the CSSCS region by synthesizing relevant data from previous literature and our own observations and displaying the evolution of depositional systems in sequential reconstructions. Besides, the controlling factors of preferred sedimentary scenarios in the CSSCS incorporate the latest interpretations of the spreading of South China Sea (SCS) as well as the demise of the hypothetical Proto-South China Sea (PSCS). The results show that there are three types of sedimentary basins in the CSSCS (foreland, strike-slip, and rift basins) with different sedimentary filling structures. The foreland basins formed a depositional pattern of ‘transition from deep water to shallow water environments’, dominated by deep-water depositional systems which were formed before the Early Oligocene with submarine fans developed. Later, the foreland basins were gradually dominated by shallow-water depositional systems with deltas and shallow marine facies. The strike-slip basins showed the depositional architecture of ‘transition from lake to marine environments’, i.e. the basins were dominated by lacustrine deposits during the Eocene and evolved into the marine depositional environment since Oligocene with delta developed in the western part of the basin. The depositional evolution of rift basins illustrated the characteristics of ‘transition from clastic to carbonate deposits’, i.e., the rift basins were dominated by Eocene–Oligocene shallow marine clastic depositional systems, while carbonate platforms started to develop since the Early Oligocene from east to west. The above-mentioned differences of depositional architecture in the CSSCS were controlled by the scissor-style closure of the PSCS and the progressive-style expansion of the SCS. Specifically, the early-period deep-water sedimentary environment of CSSCS basins was controlled by the distribution of PSCS in the Eocene. As the scissor-style closure of PSCS progressed from west to east during the Oligocene to Early Miocene, the northwest of Borneo continued to rise, providing a great number of clastic materials to the basins and gradually developing large-scale deltas from west to east. The distribution of early-period lacustrine sedimentation of strike-slip basins was affected by paleo uplift, and the basins transgressed from the northeast and gradually evolved into marine sedimentary environment due to the expansion of SCS. The expansion of SCS also controlled the sedimentary filling evolution of the rift basins, which broke away from the South China continent and drifted southward. Thus, the rift basins lacked the supply of terrigenous clastic sediments which hindered the development of large-scale deltas and formed a clear water environment conducive to the development of carbonate platforms from east to west.

Geochemistry and Zircon U–Pb Geochronology of the Wugongshan Granites in the Northwestern Jiangxi Area, China: Implications for the Paleozoic Tectonic Development of South China

The properties of the Caledonian orogeny along the transition belt of the Yangtze and Cathaysia blocks have received much attention in recent years. The widespread Early Paleozoic granites provide critical geological clues for unraveling the tectonic evolution and geodynamic processes of the South China Continent (SCC). Here we present new zircon U–Pb chronology, whole-rock major and trace elements, in situ Hf isotopes for Paleozoic granites, i.e., the Wugongshan granites in the northwest Jiangxi province, and aim to explore the magmatism and properties of the Caledonian orogeny involved in their formation. Our new data show that the Wugongshan granites were emplaced during the Early Silurian Period (442–438 Ma). The Paleozoic Wugongshan granites belong to S-type muscovite-bearing peraluminous granites (MPG) and show a single origin. The Wugongshan granites exhibit negative εHf(t) values (−11.56 to −6.19) and TDM2 model ages of 2148–1809 Ma, indicating their derivation from an ancient crustal source, through partial melting of ancient crustal material. The Wugongshan granitic magmatism is probably being generated in an extensional environment related to an intracontinental orogeny setting. It is inferred that the Paleozoic tectonic–magmatic event in the Wugongshan area was associated with the oceanic–continental convergence of the Paleo-Tethys Ocean. The Wugongshan granites highlight the intracontinental magmatism in the Early Paleozoic orogeny in the SCC.

High-resolution lithospheric structure of continental China from joint inversion of surface wave and gravity data

The lithospheric structure of continental China has been previously determined by seismic travel time tomography, surface wave tomography, and joint inversion of body wave and surface wave data. However, due to the inherent limitations of seismic data, the lithospheric structure of continental China is still not well resolved in the shallow part and in some regions where the station coverage is relatively sparse. In this study, we aim at improving the lithospheric structure by joint inversion of seismic surface wave data and satellite gravity data to take advantage of the uniform distribution and complementary strength of the gravity data. The empirical relationship between velocity and density is used as a bridge for joint inversion of surface wave and gravity data. The joint inversion shear-wave velocity Vs (density) model, named as USTClitho1.0g, can fit both surface wave and gravity data well. This high-resolution Vs model can better fit the active airgun source seismic arrival times and better delineate some features in continental China, such as the velocity contrast across the north–south gravity lineament (NSGL), the lithosphere thinning in eastern China, the crustal footprint of the Hainan mantle plume, the likely magma chamber beneath volcanos in northeast China, the middle-lower crust low velocity layer beneath the Tibetan plateau, and the tearing of subducted Indian mantle lithosphere. Our joint inversion Vs model can provide a reference model for geosciences in continental China and surrounding areas.

Population dynamics in Taiwan from the Neolithic to early historic periods (5000–100 cal BP): Linking cultural developments and environmental change

To reconstruct population dynamics in Taiwan between 5000 and 100 cal BP, we analysed spatial-temporal changes in archaeological site abundance and size (area). The results suggest that population growth was discontinuous throughout the study region and that the main spatial differences in population trends were between eastern/northern and western Taiwan. Comparison of settlement data shows that population trends in Taiwan and different regions in continental China were partly parallel. We contrast these data with political, economic, settlement, and climatic developments in continental China, when considering possible factors that influenced these demographic relationships. In addition, we examined published palaeoenvironmental time series from the broader study region to explore human-environment interactions. This revealed that proxy records of human activities (agriculture, deforestation) correlate with the derived trends in site abundance and area. Furthermore, we hypothesise that the inferred sparse settlement in eastern Taiwan during 2700–1800 cal BP is related to climate change. An increase in seasonal rainfall and high-intensity precipitation events in late summer and autumn, due to long-term changes in summer monsoon precipitation and El Niño–Southern Oscillation intensity, likely resulted in unfavourable hydrological conditions for crop cultivation in this part of the study region.

Increased contribution of biomass burning to haze events in Shanghai since China’s clean air actions

High levels of East Asian black carbon (BC) aerosols affect ecological and environmental sustainability and contribute to climate warming. Nevertheless, the BC sources in China, after implementing clean air actions from 2013‒2017, are currently elusive due to a lack of observational constraints. Here we combine dual-isotope-constrained observations and chemical-transport modelling to quantify BC’s sources and geographical origins in Shanghai. Modelled BC concentrations capture the overall source trend from continental China and the outflow to the Pacific. Fossil sources dominate (~70%) BC in relatively clean summer. However, a striking increase in biomass burning (15‒30% higher in a fraction of biomass burning compared to summer and 2013/2014 winter), primarily attributable to residential emissions, largely contributes to wintertime BC (~45%) pollution. It highlights the increasing importance of residential biomass burning in the recent winter haze associated with >65% emissions from China’s central-east corridor. Our results suggest clearing the haze problem in China’s megacities and mitigating climate impact requires substantial reductions in regional residential emissions, besides reducing urban traffic and industry emissions.

Geochemical Characteristics and Geological Significance of Black Shale at the Bottom of the Mufushan Formation in the Lower Cambrian, Lower Yangtze Platform, South China

Black shale, as an important unconventional energy resource, has attracted significant attention in recent years. By studying its sedimentary and geochemical characteristics, it is possible to reconstruct ancient depositional environments and paleoclimatic conditions. The Lower Cambrian black shale is widely distributed in the Lower Yangtze region, but its tectonic background and provenance have been subject to debate. In this study, we conducted geochemical testing and analysis on samples collected from the basal black shale of the Mufushan Formation in the Mufushan section, Nanjing. The Th/Sc-Zr/Sc diagram indicates that the black shale of the Mufushan Formation has not undergone sedimentary recycling. Analysis of major element ratios, rare earth element (REE) distribution patterns, δEu, (La/Yb)N, and the La/Th-Hf and La/Yb-∑REE discrimination diagrams suggest that the source rocks of the black shale mainly consist of granites and sedimentary rocks rich in ferromagnesian minerals, representing felsic rocks derived from the upper crust, with some involvement of mafic rocks. Considering the provenance attributes, geological age relationships, and tectonic evolution of the South China continent, the granite component in the source rocks is inferred to have formed during Neoproterozoic magmatic activity, and the source area corresponds to the Jiangnan Orogenic Belt. Analysis of K2O + Na2O-SiO2, K2O/Na2O-SiO2/Al2O3, La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 diagrams suggests that the source area of the Mufushan Formation black shale was a passive continental margin.

Duration of the Huangling Dome Activity in the Northern Margin of the South China Continent: Insight From Integration of Zircon (U–Th)/He Dating and Thermal Modeling

AbstractThe Huangling dome, which is one of the largest tectonic domes in the South China continent, was formed between the Late Jurassic and Early Cretaceous, when regional compression was eventually replaced by regional extension. This raises an issue about whether the dome was generated by compression, extension or both. This study integrates single‐grain zircon (U–Th)/He (ZHe) dating with thermal modeling to better constrain the formation process of the dome. The measured ZHe ages of samples collected from the dome and adjacent synclines are all younger than the depositional or crystallization ages of the sampled rocks, and the western and eastern dome sides have much older ZHe mean ages than those of the dome and synclines' cores. They make clear the complex interactions between uplift, denudation, and heating processes during dome formation. For simplicity, we developed one‐dimensional heat‐conduction models that cover a wide range of heating and exhumation scenarios (assuming that uplift rate equals denudation rate) within an interval of 152.1–121.4 Ma. These models were solved and searched for the predictions of the measured ages. The best models have a fast decrease in uplift rate with time and a constant heating rate, indicative of an early interval shaping of the dome in a compressional setting.

Molecular phylogenetic analysis and its impact on the conservation of Ischnura rubilio Selys, 1876 (Odonata: Coenagrionidae) in Taiwan

Although Ischnura aurora (Brauer, 1865) was traditionally considered to be widely distributed in Asia, the populations west of continental China have recently been identified as equivalent to Ischnura rubilio Selys, 1876. While the Taiwanese population has long been regarded as I. aurora as well, Taiwan in fact represents the distribution boundary between I. aurora and I. rubilio. Based on molecular and morphological analyses, we confirm that the “I. aurora-like” damselfly in Taiwan corresponds to I. rubilio. It is noteworthy that the abdominal blue spots of males in the Taiwan population have a unique phenotype compared to those found in specimens from India and continental China. According to past references and current surveys, the I. rubilio population in Taiwan has critically declined, with only one confirmed locality currently remaining. To maintain the Taiwanese population of I. rubilio, we recommend that prompt conservation measures of the habitat be implemented, focusing on the concept of the Satoyama Initiative.

Platoplusia florianii, a new species from north-western Yunnan, China (Lepidoptera: Noctuidae: Plusiinae)

A new species of the genus Platoplusia Ronkay, Ronkay & Behounek, 2008, Platoplusia florianii sp. n. is described from Yunnan Province (continental China). The new species is the second known member of the genus Platoplusia which was considered to be monotypic. Adults and male genitalia are illustrated.