Liaodong Peninsula Research Articles

Petrogenesis of the Early Paleoproterozoic Felsic Metavolcanic Rocks from the Liaodong Peninsula, NE China: Implications for the Tectonic Evolution of the Jiao-Liao-Ji Belt, North China Craton

The early Paleoproterozoic (ca. 2.2–2.1 Ga) tectonic evolution of the Jiao–Liao–Ji belt (JLJB) is a continuous hot topic and remains highly controversial. Two main tectonic regimes have been proposed for the JLJB, namely arc-related setting and intra-continental rift. Abundant ca. 2.2–2.1 Ga volcanic rocks were formed in the JLJB, especially in the Liaodong Peninsula. These ca. 2.2–2.1 Ga volcanic rocks therefore could host critical information for the evolution of the JLJB. In this study, we report a suit of ca. 2.2–2.1 Ga felsic metavolcanic rocks in the Liaodong Peninsula of the JLJB to provide new insights into the above issue. Zircon U-Pb dating reveals that the felsic metavolcanic rocks were erupted at 2185–2167 Ma. They have variable εHf(t) values (−0.70 to +9.69), high SiO2 (66.30–75.30 wt.%) and relatively low TiO2 (0.03–0.78 wt.%), tFe2O3 (0.55–5.03 wt.%), MgO (0.17–8.76 wt.%), Cr (9.16–67.30 ppm), Co (2.01–7.00 ppm) and Ni (3.90–25.70 ppm) contents with enrichments in light rare earth element (REE) and large ion lithophile element (LILE), and depletions in heavy REE and high field strength element (HFSE). Geochemical and isotopic results indicate that the felsic metavolcanic rocks were sourced from partial melting of ancient Archean TTG rocks and juvenile lower crustal materials. Combined with coeval A-type granites, bimodal volcanic rocks and the absence of typical arc magmatism, the most likely tectonic regime at ca. 2.2–2.1 Ga for the JLJB is an intra-continental rift.

Seismogenic Structure of the Hidden Haicheng Fault System in China Revealed by Seismic Observations from 2008 to 2018

ABSTRACT The hidden Haicheng fault system is an earthquake-prone zone on the Liaodong Peninsula, China. Its seismogenic structure is still unclear and needs further study. In this study, we used the differential evolution algorithm to invert the waveform data of the 2008 ML 4.8 Haicheng earthquake and the 2012 ML 4.8 Gaizhou earthquake and obtained an updated 1D crustal velocity model. The model reveals a low-velocity zone with a depth of 18–24 km below the Haicheng fault zone. Based on the velocity model, we used the arrival-time data to accurately locate the earthquakes that occurred in the Haicheng area from 2008 to 2018. The relocated earthquakes show that the Az 300°-trending Haicheng fault consists of two segments spaced about 2 km apart, namely the western and the eastern segments. They are about 12 and 22 km long and inclined to the northeast with dips of 70° and 80°, respectively. These seismogenic structures of the Haicheng fault zone are important for assessing the future seismic risk in the region.

Geochronology and Geological Implications of Paleoproterozoic Post-Collisional Monzogranitic Dykes in the Ne Jiao-Liao-Ji Belt, North China Craton

Hardly any previous studies have focused on the granitic dykes which intrude into the Paleoproterozoic Liaohe Group in the Liaodong Peninsula, northeast of the North China Craton. In situ zircon U-Pb dating, Lu-Hf isotopic and geochemical analyses on three representative monzogranite dykes were taken in this study. These dykes have relatively high content of SiO2 (72.20%–74.78%) and K2O (2.83%–6.37%), and have characteristics of high-K calc-alkaline to shoshonite series. Two dyke samples have I-type granite features and have high Sr/Y ratios and positive Eu anomalies, showing an adakitic feature. Another dyke has a high ratio of Ga/Al, but has a low Zr saturation temperature, which differs from the typical A-type granite. Zircon grains from these three dykes have typical magmatic zoning in CL images and yield consistent U-Pb ages of ~1859–1852 Ma, which are interpreted as the crystallization ages of these dykes. Hf isotopic analyses yield mainly negative εHf(t) values and TDM2 ages of 2782–2430 Ma, similar to those of the 2.2–2.1 Ga granitoids and meta-sedimentary rocks (the Liaohe Group), indicating these monzogranitic dykes may have been sourced from melting of Paleoproterozoic granitoids and meta-sedimentary rocks. The monzogranitic dykes were generated under a post-collisional geological setting after the Jiao-Liao-Ji orogeny process.

Mafic–felsic igneous rocks in the north‐eastern North China Craton, eastern Jilin, NE China: Petrogenesis and implications for regional geodynamic evolution during the Cretaceous

We present zircon U–Pb ages, major and trace element analyses and zircon Hf isotope data on the Cretaceous mafic–felsic igneous rocks in the north‐eastern North China Craton (NCC) of NE China. These data have been used to discuss the petrogenesis of the mafic–felsic igneous rocks in order to constrain the geodynamical and magmatic evolution of the region. Zircon U–Pb dating results indicate that these igneous rocks crystallized during the Cretaceous (ca. 123–90 Ma). These mafic igneous rocks display low SiO2 contents, high MgO contents and marked enrichments in large‐ion lithophile elements (LILEs) and depletions in high‐field‐strength elements (HFSEs), combined with their εHf(t) values and La/Nb versus La/Ba diagram, suggesting they were derived from lithospheric mantle that experienced gradually increasing fluid metasomatism from 123 to 90 Ma. The felsic igneous rocks with high SiO2 values are metaluminous to weakly peraluminous and belong to the high–K calc–alkaline series. These felsic igneous rocks are all enriched in light rare earth elements (LREEs) and LILEs and relatively depleted in HFSEs, with barely negative Eu anomalies, combined with their εHf(t) values, these felsic igneous rocks were derived from partial melting of a lower crust. A synthesis of these new data with previous researches shows that the subduction and rollback of the Palaeo‐Pacific slab played a major role in the destruction of the north‐eastern NCC. The diagenetic temperatures of igneous rocks indicate that the mechanism of destruction of the NCC may be heterogeneous, most likely a thermal erosion mechanism in eastern Jilin area and a delamination mechanism in Liaodong Peninsula.

A metamorphic devolatilization model for the granitoid-hosted Wulong lode gold deposit, Liaodong Peninsula, Eastern North China Craton: Evidence from geology, fluid inclusions, and O-Sr-Li isotopes

The genesis of the gold deposits in the eastern North China Craton (NCC) has long been disputed. Many would relate the gold mineralization to magmatism. The Wulong in the Liaodong Peninsula is a classic example in the eastern NCC and was considered to be of magmatic hydrothermal origin previously. Nevertheless, we propose a metamorphic devolatilization model to explain its genesis based on geological, fluid inclusion and O-Sr-Li isotopic study. The geological profiles, temperatures, salinities, and O isotopes of the ore-forming fluids at Wulong show no spatial variations over a 600 m vertical depth interval. These evidence convincingly prove its vertically extensive feature, which is similar to orogenic gold deposits, but different from magmatic hydrothermal systems. The initial Sr isotopes of the ore-forming fluids (0.71435 to 0.71578) fall into the range of metabasalts from the Liaohe Group (the Paleoproterozoic basement), indicating that metabasalts are the probable sources. Lithium and its isotopic modelling further suggest that metamorphic devolatilization of metabasalts (with chain silicates Ch, phyllosilicates Ph, and quartz Qtz as endmembers; Ch, Li ≈ 5 ppm, δ7Li ≈ 8‰; Ph, Li ≈ 63 ppm, δ7Li ≈ −1‰; Qtz, Li ≈ 10 ppm, δ7Li ≈ 30‰) could account for the Li concentrations (5–41 ppm) and δ7Li value of the fluid (21.4‰) of the Wulong gold deposit. Rayleigh fractionation in a closed system led to large Li isotopic variation of the ore-forming fluids (21.4 to 11.0‰). The metamorphic devolatilization model based on the vertically extensive feature, Sr isotopic constraint and Li isotopic modelling is in striking contrast with previous qualitative isotopic studies that support a magmatic hydrothermal origin for the Wulong and other granitoid-hosted gold deposits in the eastern NCC. Integrated with geological characteristics and radiogenic isotopes, this study here shows that Li isotopes can provide new constraints on the genesis of orogenic gold deposits.

Jurassic Au–Ag mineralization of the Linjiasandaogou deposit in the Liaodong Peninsula, northeast China: Evidence from apatite U–Pb dating and the in situ geochemistry of sulfides

The Liaodong Peninsula in northeast China hosts visible and invisible Au-dominated mineralization. Compared with visible Au, age and mechanisms of invisible Au-dominated mineralization are still unclear. The Linjiasandaogou deposit in the Liaodong Peninsula comprises disseminated and veinlet ores hosted in Paleoproterozoic schist and Triassic granite porphyry and lamprophyres. Three mineralization stages were identified in this deposit: the early pyrite (Py1), arsenian pyrite (Py2)–arsenopyrite–sphalerite (Sp1)–quartz–apatite, and freibergite–sphalerite (Sp2)–galena–quartz stages. Gold mineralization is mainly in invisible forms and was deposited during the second stage, whereas Ag was deposited during the third stage. Uranium-Pb dating of hydrothermal apatite from the second stage indicates that Au mineralization occurred at ca. 184 Ma, when the Yaojiagou granite was emplaced. In situ S isotope analysis shows that sulfides which formed during the mineralization stages have a narrow range of δ34SV-CDT values (4.80 ‰–8.53 ‰) that are typical of a magmatic–hydrothermal system. Py2 has higher As, Au, and Ag contents of 15,100–95,576, 15.4–183, and 20.8–129 ppm, as compared with Py1 (As <0.9–11,050 ppm, Au <0.03–11.1 ppm, and Ag <0.05–48.5 ppm). The negative correlations between As–S and Au–Fe in pyrite are indicative of As substitution for S and Au substitute for Fe in the pyrite. The pyrite and sphalerite trace element compositions indicate that the formation temperatures of the three stages were >250 °C, 154–252 °C, and 167–197 °C, respectively. The evolution of the hydrothermal system indicates that the deposition of Au is due to cooling and fluid-rock interaction, whereas the precipitation of Ag results from an increase in the sulfidation state. Results suggest the invisible Au-dominated mineralization in the Linjiasandaogou deposit was associated with the Early Jurassic intrusion. This study supplements the ore-forming epoch framework of the Qingchengzi ore field and improves the understanding of the Au–Ag mineralization in this area.

Comparative analysis of two impact systems in a snowstorm in Dalian

In this study, the two influence systems in a snowstorm that occurred in January 2021 are analyzed using conventional observation, intensive snowfall observation data and NCEP-FNL 0.25°×0.25° analysis data. The results show that, first, the westerly trough combined with the surface convergence line and the sub cold front produces strong snowfall in the southern part of the Liaodong Peninsula, then the strong cold air moves southward into the cold flow snowfall. When the westerly trough system has a large water vapor flux, deep wet layer and strong ascending motion, the surface is accompanied by the obvious warm tongue in southwest Dalian and cold pad in the inland, and there is obvious frontogenesis process, with heavy snowfall. The intensity of cold advection is closely related to the amount of snowfall: the stronger the cold advections, the greater the snowfall will be. The combination of mid-upper-level divergence with negative vorticity and convergence with positive vorticity near the ground is also an advantage for heavy snowfall. Cold flow snowfall exhibits strong local characteristics. Compared with the westerly trough system, the cold flow snowfall has a smaller influence area and intensity. The combination of strong ascending motion and wet area is also one of the focuses of cold flow snowfall forecast in Dalian.

해적 張伯路와 2세기 전반 동아시아 국제정세

This study examined the East Asian international situation during the 2nd century, by focusing on the Yellow Sea pirate, Zhang Bolu, and explored the historical significance of his pirate activities. In March 111, Buyeo attacked Lelang Commandery of Later Han Dynasty while Goguryeo attacked Xuantu Commandery of Later Han Dynasty. Both countries mobilized their national forces and the kings themselves participated in the attack. It is highly likely that both countries mutually agreed on attacking Later Han Dynasty. Liaodong-Yemaek in Suzihe river basin joined Goguryeo, and Eupru which was subordinated to Buyeo also supported Buyeo too. In March 111, anti-Later Han forces rapidly expanded around the Northeast Asian countries. This study focused on Pirate Zhang Bolu for such international situations.&#x0D; The Zhang Bolu forces grew through marine activities around Hebei and Shandong provinces. In 109 to 110, the forces grew their power around Shandong and surrounding regions. The Zhang Bolu forces also claimed them as an independent kingdom. In April 110, however, they left Shandong Peninsula and moved to southern Liaodong Peninsula because they were unable to withstand the attack of Later Han Dynasty. Nevertheless, the Zhang Bolu forces continued attacking southern Liaodong Peninsula and eastern Shandong Peninsula by centering on Miaodao Islands and Changshan Islands until the first half of 111. The maritime activities of Zhang Bolu forces blocked the direct transportation between Liaodong Commandery, Lelang Commandery, and Xuantu Commandery with the Later Han Dynasty from 109 to the first half of 111. The military forces of Liaodong Commandery were mobilized to fight against the Zhang Bolu forces while Lelang Commandery and Xuantu Commandery were isolated. In March 111, Buyeo and Goguryeo attacked Later Han Dynasty and it is considered that such attack was associated with the maritime activities of the Zhang Bolu forces. In April 111, Later Han suppressed the Zhang Bolu forces. The Later Han Dynasty organized Liaodong Commandery, Lelang Commandery, and Xuantu Commandery and Buyeo and Goguryeo established an amicable relationship with Later Han again. This shows that the international relations of Buyeo and Goguryeo, which were formerly anti- Later Han countries, were associated with rise and fall of the Zhang Bolu forces. The Shandong Peninsula, Liaodong Peninsula, and northwestern Korean Peninsula were connected with Myodo-Jangsan Coastal Routes in the early stage. Han Dynasty installed Liaodong Commandery, followed by Lelang Commandery to expand negotiation and trade.&#x0D; As a result, Myodo-Jangsan Coastal Routes were built and operated as marine routes for general uses and surrounding regions developed with commerce and fishery. However, people were often overwhelmed because acts and taxes were forcedly imposed by centering on inland agricultural society. So, people living in the islands and sea left their lands. The several examples of pirates during 1st century to 3rd century show the independence of the sea world in contrary to the land forces. The Zhang Bolu forces during the 2nd century were associated with the East Asian international situation by reflecting the growth of Myodo-Jangsan Coastal Routes. This implies the historical significance of the Zhang Bolu forces in the sea world.

Research into the Spatiotemporal Characteristics and Influencing Factors of Technological Innovation in China’s Natural Gas Industry from the Perspective of Energy Transition

Promoting technological innovation in the natural gas industry is a feasible means of achieving energy transition. Guided by the geographic innovation theory, this article carries out research on the scale, technical fields, capabilities, and influencing factors of technological innovation in the natural gas industry of 312 Chinese prefecture-level cities, making use of the cusp catastrophe model, the center of gravity and standard deviational ellipse, exploratory spatial data analysis, and geographically and temporally weighted regression (GTWR). The research shows the following: (1) Technological innovation in China’s natural gas industry has continuously expanded in terms of scale, with the number of participating cities increasing, showing a spatially uneven pattern of local agglomeration and national diffusion. (2) There have been significant innovation achievements in natural gas equipment and engineering, but natural gas utilization is lagging in comparison, with drilling, new materials, environmental protection, pipe network engineering, and digital services becoming frontier fields, and collaborative innovation with the thermoelectric, metalworking, automotive, and other related industries having been initially established. (3) The unevenness of technological innovation capabilities is obvious, with the core advantages of Beijing–Tianjin being continuously strengthened and Sichuan–Chongqing, the Yangtze River Delta, the Pearl River Delta, Shandong Peninsula, and Liaodong Peninsula forming high-level technological innovation capability agglomerations. (4) The spatiotemporal pattern of technological innovation capability is the result of multiple factors, with northeastern cities mainly being affected by natural gas demands, northwestern cities being highly sensitive to capital strength, eastern cities mostly relying on urban development, and cities in North China mainly being bolstered by the strength of talent. (5) It is necessary to carry out further multi-agent and multi-scale future research on technological innovation in the natural gas industry and its relationship with the energy transition and to explore the interactivity of the influencing factors. This study may provide strategies for technological innovation in the natural gas industry from the perspective of the energy transition.

Metallogeny of the Xiaotongjiapuzi gold deposit, Liaodong Peninsula (Eastern China): Perspective from sulfide trace element geochemistry and sulfur isotopes

Most gold ores have variable sulfur isotopic and trace elemental compositions at micro-/nano-scale, which makes the understanding of the gold formation process more challenging. The advancement of in-situ analytical techniques offer opportunity to gain insight into gold mineralization processes and ore-material source. The Xiaotongjiapuzi is a representative intrusion-related gold deposit in the Qingchengzi orefield of the Liaodong Peninsula, Eastern China. Alteration and gold mineralization comprise four stages: (I) quartz-pyrite-Au, (II) quartz-pyrite-biotite-Au, (III) Au-barren quartz-pyrite, and (IV) post-ore quartz-calcite. Detailed scanning electron microscope (SEM) backscattered electron (BSE) imaging, electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) elemental and LA–multi-collector (MC)–ICP–MS sulfur isotope analyses were conducted to reveal the ore-material source and mineralization process. Three texturally distinct auriferous pyrite generations were identified: Py1 and Py2 (in both stage I and II) and Py3 (in stage II and III). Py1 is porous and weakly fragmented, poorly crystallized, and overgrown by Py2. Py2 is commonly intergrown with arsenopyrite and marcasite, whilst Py3 overgrew around Py2 or replace it.Gold exists mainly as solid solution (Au+) in the pyrite lattice and nanoparticles (Au0), as well as (rare) micron-scale inclusions along the Py2-Py3 interface. Py2 has the highest gold content (mean 47 ppm, max 344 ppm), especially when intergrown with marcasite (Mrc1). The δ34S values of pyrite (5.71–15.31‰, n = 18) and marcasite (-19.59 to 7.45‰. n = 6) are the highest and lowest, respectively, and the values increase steadily from Py1 to Py3 (Py1: 5.71–7.54‰ → Py2: 7.44–9.55‰ → Py2 + Mrc1: 12.88–13.92‰ → Py3: 15.17–15.31‰). The Paleoproterozoic Dashiqiao and Gaixian formation host rocks contain large amount of sulfate minerals (e.g., barite and gypsum), and the coeval global sulfate has heavy sulfur isotope enrichment, suggesting that sulfate reduction may have provided H2S-rich fluids [Au(HS)2- and/or Au(HS)0] for the Mesozoic mineralization. For the multistage gold enrichment at Xiaotongjiapuzi, we suggest that the Paleoproterozoic sedimentary and metamorphic rocks may have formed the initial sulfur reservoir, which was then reactivated by Mesozoic magmatic-hydrothermal events.

Magma Source and Petrogenesis of the Early Cretaceous Granites in The Liaodong Peninsula: Evidence from In Situ Apatite Sr-Nd and Zircon Hf-O Isotopes

Apatite Sr-Nd and zircon Hf-O isotopes are broadly used to trace magma sources and constrain magma evolution processes, further improving our understanding of the origin of granitoids. We present zircon U-Pb ages, whole-rock major and trace elements, and whole-rock Sr-Nd-Hf, zircon Hf-O, and apatite Sr-Nd isotopic data for the coarse-grained quartz monzonite, biotite monzogranite, and granite porphyry in the Yushulinzi pluton in the Liaodong Peninsula, the eastern North China Craton, to establish their magma sources and petrogenesis. The coarse-grained quartz monzonite, biotite monzogranite, and granite porphyry were formed contemporaneously, with zircon U-Pb ages of 123–119 Ma. They share enriched whole-rock Sr-Nd-Hf and zircon Hf isotopic compositions, and the coarse-grained quartz monzonite has crust-like δ18O values (5.7–6.7‰). The coarse-grained quartz monzonite and biotite monzogranite have variable apatite (87Sr/86Sr)i ratios and negative apatite εNd(t) values. These isotopic characteristics indicate that the different rock types in the Yushulinzi pluton were derived from the partial melting of ancient crustal material in the North China Craton. Their geochemical and petrographic characteristics indicate that the crystal-melt segregation model can be employed to elucidate the genetic links among different rock types, with the coarse-grained quartz monzonite representing crystal accumulation and the biotite monzogranite and granite porphyry representing interstitial melts extracted from a crystal-rich magma chamber. Furthermore, the variable apatite Sr isotopic compositions and subtle differences in the peak zircon εHf(t) values of the studied rock samples confirm the possibility of a contribution from shallow crustal components and materials with high εHf(t) values during magma evolution, which is not readily revealed by their whole-rock Sr-Nd-Hf isotopic compositions. These results demonstrate that in situ apatite Sr-Nd and zircon Hf-O isotopic analyses have the potential to provide distinctive insights into the magma sources and evolution of magmatic systems.

The Middle–Late Triassic fold–thrust belt on Liaodong Peninsula, North China Block: Implication for propagation of the Sulu orogeny toward the NE

The Middle–Late Triassic fold–thrust belt on Liaodong Peninsula, North China Block: Implication for propagation of the Sulu orogeny toward the NE

『사기』 「조선열전」에 나타난 패수 위치 고찰

Regarding the geography of ancient Korea, the location of the Pei River, which formed the border between the Western Han dynasty and the Joseon of Wiman, has long been a subject of sharp debate. This is because the Pei River is regarded as the western boundary of Gojoseon. The problem is that since the name Pei was recorded in the Records of the Shiji (史記), the course of the river has changed over time, and so various claims about its position have been presented. The theories concerning the location of the Pei River can be divided into the Korean Peninsula theories (Taedong River, Cheongcheon River, Yalu River), the Liaodong Peninsula theories (Yuni River, Hun River), and the former province of Liaoxi theories (Daling River, Luan River, Chaobai River). The theories claiming that the Pei River is either the Cheongcheon River or the Yalu River in North Korea have received the most support from domestic academia. However, the Korean Peninsula theories and the Liaodong Peninsula theories both have a problem in that the location and direction of the Pei River were not verified according to records made around the time such as the Hanshu (漢書), the Shuowen Jiezi (說文解字), and the Shuijing (水經). There was a Pei River on the border of Liaodong during the Western Han and, at that time, Liaodong appears to have been located in literature in the present-day Beijing area. Since the capital of Wiman Joseon was said to be in Changli County, Hebei Province, the Pei River recorded in the Records of the Shiji can only be a river between Beijing and Changli Count

Role of metasomatized mantle lithosphere in the formation of giant lode gold deposits: Insights from sulfur isotope and geochemistry of sulfides

The Wulong deposit is one of the largest quartz vein-type gold deposits with at least 80 tons of identified gold reserves in the eastern part of the Liaodong Peninsula. Gold orebodies are mainly hosted in the Late Jurassic gneissic two-mica granite and Early Cretaceous diorite dykes, and are structurally controlled by the NNE- and NW-trending faults. Gold mineralization mainly occurs as veins with lenticular shapes and is closely associated with sulfides and Bi minerals. Previous studies on the deposit mainly focused on its geological characteristics, fluid inclusions and the timing of gold mineralization. However, the extreme enrichment mechanism of gold, the geodynamic setting and ore source of the gold deposit remain equivocal. Here we present results from geochemical studies of pyrite and pyrrhotite at Wulong to address these issues. Pyrrhotite can be grouped into euhedral (Po1) and anhedral (Po2) varieties based on the textures. Four generations of pyrite were identified based on petrographic studies: Py1 is coarse-grained subhedral to euhedral crystal coexisting with milky quartz, and Au-depleted in composition; Py2 is represented by medium-grained, subhedral to anhedral pyrite coexisting with euhedral Po1, smoky quartz and minor chalcopyrite; Py3 occurs as fined-grained anhedral grains in the quartz-polymetallic sulfide veins; Py4 occurs as veinlets or aggregates in the quartz-calcite veins and contains the lowest Au concentrations. The time-resolved LA-ICP-MS ablation depth profiles of sulfides combined with detailed petrological observations indicate that gold mainly occurs either as invisible solid solution within the crystal lattice of sulfides, to some extent, or as small blebs of native gold and electrum. The close temporal and spatial relationships among native bismuth, native gold and Bi-Te-S minerals suggest that Bi-rich melts may have significantly sequestered gold from the hydrothermal fluids in the Wulong gold deposit. Sulfides from auriferous quartz veins have a restricted Δ33S range (−0.2‰ to +0.2‰) and a mean δ34S value of +1.25‰ with a feature of the mass-dependent fractionation (MDF) of sulfur isotopes, implying that the ore-forming materials were potentially derived from the mantle lithosphere that was metasomatized and fertilized by subduction-related fluids released from slab during the Early Cretaceous. This study demonstrates the Bi-rich melts as significant gold scavengers in As-deficient ore-forming fluid, and highlights the fundamental role of the metasomatized and fertilized mantle lithosphere in the formation of giant lode gold deposits in the eastern North China Craton at ca. 120 Ma.

The control of deformation partitioning on gold mineralization in the Qingchengzi district, Liaodong Peninsula, northeastern China

The control of deformation partitioning on gold mineralization in the Qingchengzi district, Liaodong Peninsula, northeastern China

Profile of atmospheric VOC over the Yellow Sea, China: A tale of distribution, constraints, and sources

In the winter of 2018–2019, 75 air samples were collected through four ship-borne measurements in the Yellow Sea (YS) to assess the levels, confinement processes, and source distribution of volatile organic compounds (VOCs). A total of 41 were eventually detected, which mainly were non-methane hydrocarbons (NMHCs), volatile halogenated hydrocarbons (VHCs), oxygenated volatile organic compounds (OVOCs), and volatile organic sulfur compounds (VSCs). Aromatics (31.93 %) and alkenes (11.04 %) in the atmosphere of the YS accounted for a larger proportion of NMHCs compared with the coastal areas. C3-C5 alkanes, propylene, and chloroform exhibited strong latitudinal gradients and opposite latitudinal distributions in the North and South YS, highlighting the strong contribution of regional outflow to YS's atmosphere. The level of Σ41VOCs increased significantly during the heavy pollution period with some chemical monomers detected, which was further enhanced by the emissions from industrial parks near the Liaodong Peninsula and the Shandong Peninsula. Five main VOC sources were identified by the Positive matrix factorization (PMF) model, which were industrial emissions (13.33 %), fuel use and volatilization (6.67 %), Freon R-22 emissions (33.33 %), oil and gas production (20.00 %), and solvent volatilization (26.67 %). These observations revealed the strong causal relationship between coastal air mass transport and the atmosphere in the marginal sea and emphasized that full attention should be paid to the unintentional and unorganized emission of chemical monomers in the industrial process.

고구려 안시성 지리적 위치에 대한 새로운 고찰

In the region of Liaodong peninsula, there are many historic sites of Goguryeo city, and Anshi city is one of them. Anshi city has a very important position in the history of Goguryeo, in where the famous Battle of Anseong took place. Over the years there have been many opinions about the specific positioning of Anshi city. On the basis of synthesizing the views of previous scholars, collating literature and field investigation, this paper intends to make a further examination of the geographic position of Anshi city.

Decreasing summer monsoon precipitation during the Mid-Pleistocene transition revealed by a pollen record from lacustrine deposits of the Northeast Plain of China

The Mid-Pleistocene transition (MPT) was characterized not only by the transition of ice volume periodicities from 40 kyr to 100 kyr, but also by major changes in high latitude ice sheets, global sea level and CO2 / ocean carbon storage after ∼900 ka, which had a major influence on the evolution of the East Asian summer monsoon (EASM). However, there are different views regarding the trend of East Asian summer monsoon precipitation during the MPT and its driving mechanism. Together with published paleomagnetic and 26Al/10Be isotopic chronologies, we used pollen analysis of the lacustrine sediments of a drill core to reconstruct the vegetation history of the Northeast Plain of China. The results demonstrate a pattern of vegetation succession from coniferous and broadleaved mixed forest dominated by Pinus to woodland-steppe during the MPT, indicating a change from a semi-humid to a semi-arid climate. Palynological records from the Liaodong Peninsula, North China Plain, and the Tibetan Plateau also indicate a drying climate during the MPT, which was related to the decreasing trend of EASM precipitation. We suggest that falling global sea level caused by the expansion of high-latitude ice sheets, and the resulting the exposure of continental shelves and the increased transport distance of oceanic water vapor to the continental interior, was the main cause of the reduction in EASM precipitation. The weakening of the Atlantic meridional overturning circulation and the southward movement of the Intertropical Convergence Zone in the tropical Pacific may have been additional causes of the decrease in EASM precipitation.

Genetic Structure and Historical Dynamics of Pinus densiflora Siebold &amp; Zucc. Populations

The study of population genetic structure and historical dynamics of species with disjunct distribution can reveal the mechanisms through with they were formed. Pinus densiflora is an essential tree species with ecological and economic value, and its natural distribution shows a disjunct pattern. Using transcriptome-level SNP data from 220 samples representing 32 naturally-distributed populations in East Asia, we investigated Pinus densiflora genetic diversity and structure, divergence time, and ancestral distribution. We identified five subpopulations which diverged approximately 2.02–1.49 million years ago, and found relatively low genetic differentiation among the three large subpopulations (SL, JH, and JK). Northeast China is the most likely origin, and its current distribution is the result of dispersal and vicariance events. It migrated southwest through the Liaodong Peninsula to the Shandong Peninsula and southeast through the Korean Peninsula to Japan. These results provide a basis for the conservation and management of P. densiflora in the future and the evolutionary study of species with similar life histories.

Numerical study of higher-harmonic wave loads and runup on monopiles with and without ice-breaking cones based on a phase-inversion method

Ice-breaking cones are commonly used in the design of marine structures in cold regions. This study investigates the effects of higher-harmonic wave loads and wave runup on a 5-MW offshore wind turbine with and without ice-breaking cones under extreme wave conditions on the Liaodong Peninsula in China. Two ice-breaking cones (upward-downward and inverted types) are considered. The numerical model adopts a two-phase flow by solving unsteady Reynolds-averaged Navier-Stokes (URANS) equations using the volume of fluid (VOF) method. A phase decomposition method through a ‘Stokes-like’ formulation was adopted to obtain the parameters for each harmonics. The presence of the conical part is seen to increase the second-harmonic wave loads by up to 40%, but it has only limited influence on the fourth and fifth harmonics. The upward-downward-type ice-breaking cone increases the third harmonic, while the inverted-type ice-breaking cone decreases the third harmonic. Due to the phase difference between the first-harmonic and higher harmonics, the largest wave runup occurs at 0°, and 135° is the location with the smallest wave runup. This is because at the 135-degree location, the linear component is positive but the other nonlinear components are negative. For the 0-degree location, all harmonics are positive. By contrast, the inverted type has little effect. The high harmonic wave runup of the minimum point is backwards compared with that of the monopile, and most nonlinear wave runups are different upstream of the monopile.