The Origin of Mesozoic A-type Granitoids,Fujian Province,Southeast China:Insights from Geochronology,Mineralogy and Geochemistry

The magma sources,origins and precise forming ages of the miarolite from Qishan and Kuiqi intrusions are still uncertain.New results reveal that,miarolites from the Qishan and Kuiqi intrusions yield crystallization ages of~101 and~98 Ma,and they have a high formation temperature(~910℃)and low oxygen fugacity value,indicating crystallization condition at low pressure in the upper crust with temperature of 678℃.The Qishan and Kuiqi miarolites are characterized by enrichment in SiO_(2) and high-K alkali,depletion in Ca and Mg,and belong to the high-K weak peraluminous rock series.The samples are enriched in HFSEs(i.e.,Ta,Zr and Hf)and LILEs(i.e.,Ba,P and Sr),depleted in Ba and Sr with the negative anomaly of Eu.In the primitive mantle normalized trace element spider diagram,the samples show a right-inclined‘seagull-type’pattern,combined the ratios of(La/Yb)_(N),10000×Al/Ga,Rb/Nb and Nb/Ta etc.,they were proved to be alkaline A-type granite.Combined the characterize of the trace elements,they were derived from clay-rich source accompanied pelite melting,and subjected to K-feldspar crystallization fractional.The values of ε_(Hf)(t)and tDM2 are distributed in the range of-2.8 to 3.3 with~1.2 Ga,and-6.0 to 4.0 with~1.2 Ga,revealing that they were generated from the Mesoproterozoic Cathaysia basement rocks.The comprehensive research reveals the Kuiqi and Qishan intrusions derived from crust-mantle mixing and partial melting of the crust,respectively,resulting from lithospheric extension generated by the Paleo-Pacific Plate subducted into the European-Asian Plate.

Deep structure of the Southeast Asian curved subduction system and its dynamic process

The deep structure,material circulation,and dynamic processes in the Southeast Asia have long been an elusive scientific puzzle due to the lack of systematic scientific observations and recognized theoretical models.Based on the deep seismic tomography using long-period natural earthquake data,in this study,the deep structure and material circulation of the curved subduction system in Southeast Asia was studied,and the dynamic processes since 100 million years ago was reconstructed.It is pointed out that challenges still exist in the precise reconstruction of deep mantle structures of the study area,the influence of multi-stage subduction on deep material exchange and shallow magma activity,as well as the spatiotemporal evolution and coupling mechanism of multi-plate convergence.Future work should focus on high-resolution land-sea joint 3-D seismic tomography imaging of the curved subduction system in the Southeast Asia,combined with geochemical analysis and geodynamic modelling works.

Combating obesity in Southeast Asia countries:current status and the way forward

Obesity is gaining prominence as a serious public health challenge in the Southeast Asia(SEA)region,with an alarming rate of increase in its prevalence.Countries in the region have shown commitment to curbing the rise of obesity by establishing policies,strategies,and action plans.This paper summarises the current situation and strategies undertaken to combat obesity and related chronic diseases.Although a range of policies and strate-gies have been developed,including national nutrition action plans,community intervention programmes,fiscal measures,nutrition labelling to promote healthier choices,countries in the region are struggling to make signifi-cant progress toward halting the scourge of obesity.It is imperative to strengthen existing health systems with a paradigm shift from a focus on"sick care"to and enhancing nutrition initiatives to support obesity prevention.A comprehensive and coordinated approach is essential,one that emphasises high-level coordination across all lev-els of government and multiple sectors,and a unified plan rather than fragmented initiatives.For strategies to be effective and sustainable,they must address the fundamental environmental determinants of poor dietary choices and nutritional inequalities.A more holistic approach is clearly needed to improve the entire food environment,which in SEA countries must include the multitude of eating places where large segments of the population"eat out"everyday to meet their energy and nutrient needs.There is a recognised need for more comprehensive measures to promote healthy eating among school children and ensure a supportive environment for lifelong healthy habits.This paper calls for a whole-of-government,whole-of-society approach that combines changes to the fundamental food environment and accompanied by systematic monitoring and surveillance systems to achieve long-lasting health outcomes.

Characteristics of Lightning Activity in Southeast China and its Relation to the Atmospheric Background

Based on the lightning observation data from the Fengyun-4A(FY-4A)Lightning Mapping Imager(FY-4A/LMI)and the Lightning Imaging Sensor(LIS)on the International Space Station(ISS),we extract the“event”type data as the lightning detection results.These observations are then compared with the cloud-to-ground(CG)lightning observation data from the China Meteorological Administration.This study focuses on the characteristics of lightning activity in Southeast China,primarily in Jiangxi Province and its adjacent areas,from April to September,2017–2022.In addition,with the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis data,we further delved into the potential factors influencing the distribution and variations in lightning activity and their primary related factors.Our findings indicate that the lightning frequency and density of the FY-4A/LMI,ISS-LIS and CG data are higher in southern and central Jiangxi,central Fujian Province,and western and central Guangdong Province,while they tend to be lower in eastern Hunan Province.In general,the high-value areas of lightning density for the FY-4A/LMI are located in inland mountainous areas.The lower the latitude is,the higher the CG lightning density is.High-value areas of the CG lightning density are more likely to be located in eastern Fujian and southeastern Zhejiang Province.However,the high-value areas of lightning density for the ISS-LIS are more dispersed,with a scattered distribution in inland mountainous areas and along the coast of eastern Fujian.Thus,the mountainous terrain is closely related to the high-value areas of the lightning density.The locations of the high-value areas of the lightning density for the FY-4A/LMI correspond well with those for the CG observations,and the seasonal variations are also consistent.In contrast,the distribution of the high-value areas of the lightning density for the ISS-LIS is more dispersed.The positions of the peak frequency of the FY-4A/LMI lightning and CG lightning contrast with local altitudes,primarily located at lower altitudes or near mountainsides.K-index and convective available potential energy(CAPE)can better reflect the local boundary layer conditions,where the lightning density is higher and lightning seasonal variations are apparent.There are strong correlations in the annual variations between the dew-point temperature(Td)and CG lightning frequency,and the monthly variations of the dew-point temperature and CAPE are also strongly correlated with monthly variations of CG lightning,while they are weakly correlated with the lightning frequency for the FY-4A/LMI and ISS-LIS.This result reflects that the CAPE shows a remarkable effect on the CG lightning frequency during seasonal transitions.

Intensive High-Level Visits from Southeast Asia

Recently,senior officials from Southeast Asian countries have visited China in succession,including Indonesian Presidentelect Prabowo Subianto,Lao Deputy Prime Minister and Foreign Minister Saleumxay Kommasith,Vietnamese Foreign Minister Bui Thanh Son,Timor-Leste Foreign Minister Bendito Freitas,Vietnamese National Assembly Chairman Vuong Dinh Hue,Singaporean Deputy Prime Minister Heng Swee Keat,and Thai Princess Maha Chakri Sirinhorn.

HELLO ASEAN Visa-free policy sparks surge of Chinese tourists to Southeast Asia

As of March 1,Malaysia,Singapore,and Thailand have all implemented visa-free entry policy for Chinese citizens,allowing stays of up to 30 days.The three Southeast Asian countries have been popular destinations for Chinese outbound tourists since the late 1980s and early 1990s.The implementation of the visa-free entry policy is expected to attract more Chinese tourists,especially young people,to travel to Southeast Asia and boost the recovery of the tourism industry in the region.

Chinese Enterprises’ Investment in Southeast Asia Continues Unabated

As we all know,Southeast Asia has become a hot destination for Chinese enterprises to invest in.The latest report shows that Southeast Asia continues to attract China’s capital,within which the medical industry has become an important area for Chinese enterprises to invest in,and the investment activity has gradually warmed up despite fluctuations.

Influence of Diversity of Prototypical Ethnic Culture in Diversity of Glutinous Rice in Southeast of Guizhou

There were quite abundant prototypical ethnic cultures and plant diversity in Qiandongnan （ Southeast of Guizhou） ,where the primitive natural ecology was also perfectly conserved. It was honored by World Native Culture Fund as One of the Eighteen Ecological and Cultural Conservations in the World. The prototypical ethnic culture of Southeast of Guizhou, as a stable life-style and economic culture type of the local people, came into being in the process of the local minorities＇ communicating, blending and struggling against the natural environment in the long course of history. It could be seen from this research that there were our preliminary research that there are quite abundant resources in Southeast of Guizhou in terms of prototypical ethnic cultures and genetic diversity of glutinous rice. A full reflection of the culture of Glutinous Rice could be seen in the local minority people＇s daily life, production, custom, religious belief, etc. These showed that the formation and great vitality of the genetic diversity of glutinous rice was not only determined by the diversity of local prototypical ethnic cultures but also to its own biotic condition and its adaptation to natural ecology. It was showed that prototypical ethnic cultures had positive impact on the conservation and utilization of Glutinous Rice diversity.

Characteristics of Soil Seed Bank and Natural Regenerations in Pinus densata Natural Forest of Southeast Tibet

Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yalu Tsangpo River, Nyang River and Parlung Zangbo River. In this study, with P. densata forest distributed in southeast Tibet as research object, the seed rain, soil seed bank, seed germination and natural regeneration of P. densata were monitored and ana- lyzed by field investigation, located monitoring and indoor experimental analysis. The results showed that the average intensity of the seed rain of P. densata was 249.30±78.42 seeds/m2, in which the intensity of full seeds was 168.09±56.36 seeds/m2, the intensity of seeds damaged by worms was 41.11±20.25 seeds/m2, and the intensity of empty seeds was 40.10±21.04 seeds/m2. The intensity of the seed rain exhibited a single-peak trend of increasing at first and decreasing then over time. The spatial distribution patterns in the whole seed falling process and at different seed falling time all exhibited clumping distribution, and within in certain range, with the distance from the seed tree increasing, the diffusion intensity of the seed rain was weakened, exhibiting approximately normal distribution. In average density of P. densata seeds in the soil seed bank of P. densata was 231 seeds/m2, in which 62.77% of seeds were distributed in the litter layer, and 37.23% of seeds were distributed in the soil layer, and about 8% of seeds were lost during the pro- cess from seed rain to soil seed bank. Field sowing observation showed that the accumulated germination rate curve of P. densata fitted with Logistics equation y= 91.404/（1＋e66194.449）. The height structure, basal diameter structure and age structure of seedlings and young trees of P. densata were all of reverse ＂J＂ type, indicating good natural regeneration of P. densata. This study would provide a science basis for protection and resource management of P. densata, and further enrich the eval- uation content of national ecological safety curtain of the Tibet plateau.

Evaluation of Rice Germplasm from Southeast Asia

Totaling 662 rice germplasms were collected from Southeast Asia,including 120 wild species and 542 cultivated rice plants.An information database of the collections was constructed after phenotype identification.Based on evaluation of cultivated rice,some germplasm resources were found to have good characteristics,including 58 accessions resistant to brown planthopper,nine accessions resistant to rice blast,eleven accessions resistant to bacterial blight,and twelve accessions with salt-tolerance.The introduced rice resources broaden genetic basis of rice and enrich rice genbank in China,which would play an active role in rice genetic research and rice breeding.

Tourist Products Design of National Village Based on Experience——A Case Study of Minority Villages of Southeast Guizhou,China

On the basis of resources features of minority villages in Southeast Guizhou and tourists' experience needs,the paper proposed that national villages would increasingly be the ideal destination of cultural experience tourism under the background of experience economy,and products design centering on experience need was the common problem confronted tourism development of national villages.Through analyzing four aspects of tourist resources which were natural ecology and pastoral scenery,tangible national culture,process and event national culture,and intangible culture,the paper proposed a general method for design of tourist products of national villages.The design should be conducted by following steps of "theme extraction—image shaping—scene design—atmosphere creation—program arrangement—implication design—publicity marketing".It should establish brand image of tourist products of national villages,so as to help tourists realize "image establishment—purchasing impulse—participation into interaction—profound experience—expectation achievement",and to constantly increase the attraction power of tourist products of national villages and comprehensive economic benefit of tourism.

Impact of El Nino on Large-scale Circulation of Southeast Asian Summer Monsoon

Multi-year SST and NCEP/NCAR reanalyzed wind data were employed to study the impacts of El Nio on the Southeast Asian summer monsoon (SEASM). It was found that the impacts of El Nio on the SEASM differed distinctly from those on the East Asian summer monsoon (EASM) and the Indian summer monsoon (ISM). Composite analysis indicated that the "gear point" of coupling between the Indo-monsoon circulation and the Pacific-Walker circulation was located in the western margins of Southeast Asia when the developing stage of El Nio events covered the boreal summer. The anomalous circulations in the lower and upper troposphere and divergent circulation are all favorable for the strengthening of the SEASM during this period. Following the evolution of El Nio, the "gear point" of the two cells shifted eastward to the central Pacific when the mature or decaying period of El Nio events covered the boreal summer. The anomalous circulations are favorable for the weakening of the SEASM. The anomalous indexes of intensity of SEASM accord well with the above results. Additionally, the difference of SSTA patterns in the tropical Indo-Pacific Ocean between the two stages of the El Nio may play an important role.

Space Pattern of Rural Leisure Tourism Development in Southwest Minority Area——A Case Study of Ethnic Minority Area in Southeast Chongqing

On the basis of analysis of current research documents on rural leisure tourism, taking ethnic minority area of Southeast Chongqing for example, the paper expounded ecology, culture, authenticity and uniqueness of rural leisure tourist resources in ethnic minority area, and city-dependent, scenic area-dependent, traffic route-dependent and remote characteristic village type of space pattern.

Review and prospects: in celebration of the 20th anniversary of Journal of Southeast University (English Edition)

The twenty years history of Journal of Southeast University (English Edition) and its significant achievements are briefly reviewed. Based on the experiences accumulated over its twenty years, some suggestions for improving the quality of this English-language academic journal are proposed, including focusing on the report of the excellent disciplines of its sponsoring university, attracting high-level papers by giving the priority of publication, publishing special issues for experts and scholars at home and abroad, shortening publication period, and realizing the internationalization of the members of the editorial committee, etc.

Climatology and Interannual Variability of the Southeast Asian Summer Monsoon

In this paper, results from a pilot study for the South China Sea Monsoon Experiment are reported. Based on analyses of 9 years of pentad and monthly mean data, the climatology of subseasonal features and interannual variability of the Southeast Asian monsoon (SEAM) are documented. The present analysis is focused on the sudden onset of the South China Sea monsoon and its relation to the atmospheric and oceanic processes on the entire Asian monsoon region. \ \ It is found that the onset of the SEAM occurs around mid-May, signaling the earliest stage of the entire Asian summer monsoon system. The establishment of monsoon rainfall over the South China Sea is abrupt, being accompanied by substantial changes in the large scale atmospheric circulation and sea surface temperature in the adjacent oceans. The onset and fluctuations of SEAM involve the interaction and metamorphosis of the large scale convection over the Indo-China, the South China Sea and the southern Bay of Bengal. Results show that the onset time of the SEAM differs greatly from one year to another. The delayed (advanced) onset of the monsoon may be related to basin-wide warm (cold) events of the Pacific and Indian Oceans. We also present evidence showing that the SEAM fluctuations in May may foreshadow the development of the full-scale Asian summer monsoon during the subsequent months.

Late Mesozoic basin and range tectonics and related magmatism in Southeast China

During the Late Mesozoic Middle Jurassic--Late Cretaceous, basin and range tectonics and associated magmatism representative of an extensional tectonic setting was widespread in southeastern China as a result of Pacific Plate subduction. Basin tectonics consists of post-orogenic （Type I） and intra-continental extensional basins （Type II）. Type I basins developed in the piedmont and intraland during the Late Triassic to Early Jurassic, in which coarse-grained terrestrial clastic sediments were deposited. Type II basins formed during intra-continental crustal thinning and were characterized by the development of grabens and half-grabens. Graben basins were mainly generated during the Middle Jurassic and were associated with bimodal volcanism. Sediments in half-grabens are intercalated with rhyolitic tufts and lavas and are Early Cretaceous in age with a dominance of Late Cretaceous-Paleogene red beds. Ranges are composed of granitoids and bimodal volcanic rocks, A-type granites and dome-type metamorphic core complexes. The authors analyzed lithological, geochemical and geochronological features of the Late Mesozoic igneous rock assemblages and proposed some geodynamical constraints on forming the basin and range tectonics of South China. A comparison of the similarities and differences of basin and range tectonics between the eastern and western shores of the Pacific is made, and the geo- dynamical evolution model of the Southeast China Block during Late Mesozoic is discussed. Studied results suggest that the basin and range terrane within South China developed on a pre-Mesozoic folded belt was derived from a polyphase tectonic evolution mainly constrained by subduction of the western Pacific Plate since the Late Mesozoic, leading to formation of various magmatism in a back-arc exten- sional setting. Its geodynamic mechanism can compare with that of basin and range tectonics in the eastern shore of the Pacific. Differences of basin and range tectonics between both shores of the Pacific, such as mantle plume formation, scales of extensional and igneous rock assemblages and the age of basin and range tectonics, were caused mainly by the Yellowstone mantle plume in the eastern shore of the Pacific.

Jurassic Intra-plate Basaltic Magmatism in Southeast China:Evidence from Geological and Geochemical Characteristics of the Chebu Gabbroite in Southern Jiangxi Province

Geochemical and isotopic investigations have been carded out on the Chebu gabbroite in southern Jiangxi Province, southeast China and these results are compared with gabbro bodies along the coast of Fujian Province in order to understand their magma sources and tectonic implications. The Chebu intrusion formed at the beginning of the Middle Jurassic （172~4.3 Ma）. These rocks are Ti-rich and Al-poor in major elements, characterized by strong enrichment in large-ion lithophile elements （LILE） and moderate enrichment in high field strength elements （HFSE） and light rare-earth elements CLREE）, without pronounced Nb or Ta anomalies. Age-correlated Sr-Nd isotope ratios show moderately high ranges of （^87Sr/^86Sr）i from 0.7065 to 0.7086 and 0.5124 to 0.5125 of （^143Nd/^144Nd）i. The geochemical characteristics of the Chebu gabbroite suggest that it is notably different from island-arc basalt and similar to intra-plate basaltic rocks. By combining interpretations of its geological and geochemical characteristics and the regional geological development history, the Chebu gabbroitic intrusion is thought to be the product of asthenosphere upwelling and rapid lithosphere extension during a transition of tectonic systems in southeast China. The tectonic environment and source characteristics of the intrusion are different from Cretaceous gabbro bodies along the coast of Fujian Province, The former formed in a tectonic environment of rapid intra-plate lithospheric extension and the source characteristics were of a weakly enriched primitive mantle, whereas the latter originated mainly in a volcanic-magmatic arc extensional tectonic environment and the nature of the source was an enriched mantle with more subduct subducted components.

Crustal thicknesses and Poisson's ratios beneath the Chuxiong-Simao Basin in the Southeast Margin of the Tibetan Plateau

In the Southeast Margin of the Tibetan Plateau, low-velocity sedimentary layers that would significantly affect the accuracy of the H-κ stacking of receiver functions are widely distributed.In this study, we use teleseismic waveform data of 475 events from 97 temporary broadband seismometers deployed by ChinArray Phase I to obtain crustal thicknesses and Poisson's ratios within the Chuxiong-Simao Basin and adjacent area, employing an improved method in which the receiver functions are processed through a resonance-removal filter, and the H-κ stacking is time-corrected.Results show that the crustal thickness ranges from 30 to 55 km in the study area, reaching its thickest value in the northwest and thinning toward southwest, southeast and northeast.The apparent variation of crustal thickness around the Red River Fault supports the view of southeastern escape of the Tibetan Plateau.Relatively thin crustal thickness in the zone between Chuxiong City and the Red River Fault indicates possible uplift of mantle in this area.The positive correlation between crustal thickness and Poisson's ratio is likely to be related to lower crust thickening.Comparison of results obtained from different methods shows that the improved method used in our study can effectively remove the reverberation effect of sedimentary layers.

Pore Types and Quantitative Evaluation of Pore Volumes in the Longmaxi Formation Shale of Southeast Chongqing, China

The common microscale to nanoscale pore types were introduced and divided into organic and inorganic pores to estimate their contributions to porosity in the Lower Silurian Longmaxi Formation shale of southeast Chongqing. Following the material balance principle, the organic porosity values, which changed with formation subsidence and thermal evolution, were calculated using chemical kinetics methods and corrected via the organic porosity correction coefficient, which was obtained from field emission scanning electron microscopy. Grain density values were determined using the contents and true densities of compositions in the shale samples. The total porosity was calculated based on the grain and bulk densities. The inorganic porosity was determined from the difference between the total porosity and organic porosity at the same depth. The results show that inorganic pores mainly contain microfractures, microchannels, clay intergranular pores, intercrystalline pores and intracrystalline pores in the Lower Silurian Longmaxi Formation shale of southeast Chongqing. Organic pores mainly include organopore and fossil pore. The total porosity, organic porosity and inorganic porosity of organic-rich shale samples can be quantitatively evaluated using this method. The total porosity, organic porosity and inorganic porosity values of the Longmaxi Formation shale samples from the well Pyl in southeast Chongqing lie in 2.75%-6.14%, 0.08%-2.52% and 1.41%-4.92% with average values of 4.34%, 0.95% and 3.39%, respectively. The contributions of the inorganic pores to the total porosity are significantly greater than those of the organic pores.

Leaching and Redistribution of Nutrients in Surface Layer of Red Soils in Southeast China

The leaching and redistribution of nutrients in the surface layer of 4 types of red soils in SoutheastChina were studied with a lysimeter experiment under field conditions. Results showed that the leachingconcentrated in the rainy season (from April to June). Generaily, the leaching of soil nutrients from thesurface layer of red soils was in the order of Ca > Mg > K > NO3-N. In fertilization treatment, the totalamount of soil nutrients leached out of the surface layer in a red soil derived from granite was the highest inall soils. The uptake by grass decreased the leaching of fertilizer ions in surface layer, particularly for NO3-N.Soil total N and exchangeable K, Ca and Mg in the surface layer decreased with leaching and grass uptakeduring the 2 years without new fertilization of urea, Ca(H2PO4)2, KCl, CaCO3 and MgCO3. Ca movedfrom the application layer (0~5 cm) of fertilizer and accumulated in the 10~30 cm depth in the soils studiedexcept that derived from Quaternary red clay. The deficiency of soil exchangeable K will become a seriousdegradation process facing the Southeast China.