The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.U...The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt(CAOB)to the onset of the Paleo-Pacific subduction.In this study,we investigate epidote-ferroglaucophane(Ep-Fgl)and garnet-ferrobarroisite(Grt-Fbrs)schists from the Yilan area of the Heilongjiang Complex through petrological,mineralogical,thermodynamic modelling,whole-rock geochemical,and geochronological analyses.The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane+epidote+chlorite+clinopyroxene+phengite+titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495℃.On the other hand,the Grt-Fbrs schists exhibit a peak assemblage of garnet+glaucophane/ferroglaucophane+lawsonite+chlorite+phengite+rutile±clinopyroxene±titanite,deriving peak P-T conditions of 16.4-18.3 kbar and 457-475℃.Both types of schist record similar clockwise P-T paths,with three metamorphic stages:a peak epidote-to-lawsonite blueschist-facies stage,a post-peak decompression stage in the epidote amphibolite-facies,and a late greenschist-facies overprint stage.The Ep-Fgl schists display alkaline OIB-like geochemical affinities,while the Grt-Fbrs schists show tholeiitic MORB-like characteristics,suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust.Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276±1 Ma and 280±1 Ma,whereas zircon of Grt-Fbrs schists document protolith ages of 249±2 Ma and 248±2 Ma,indicating that the Mudanjiang Ocean existed since at least the early Permian.Reconstruction of the metamorphic P-T evolution,combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic,driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.展开更多
In recent years, with the rapid increase of economy, improvement of national life standard and dramatic expansion of urbanization, the paper has pointed out that rural area has lost its feature gradually and rural lan...In recent years, with the rapid increase of economy, improvement of national life standard and dramatic expansion of urbanization, the paper has pointed out that rural area has lost its feature gradually and rural landscape appears to be fuzzy. In view of this, survey and analysis have been conducted on rural landscape cultural types and features of Mudanjiang City, laying a foundation to the exploration and effective expression of rural landscape culture of Mudanjiang City during the planning and design of rural landscape. It hopes to protect original rural landscape connotation and regional feature, make it better adapt to the requirement of modern development, and provide a theoretical reference for the advancement of rural landscape planning in China.展开更多
Objective: to investigate and analyze the oral dentition of middle-aged and old people in Mudanjiang city, and put forward measures to improve the oral health of middle-aged and old people. Results: in 50 cases, 37 ca...Objective: to investigate and analyze the oral dentition of middle-aged and old people in Mudanjiang city, and put forward measures to improve the oral health of middle-aged and old people. Results: in 50 cases, 37 cases had complete dentition, among which the defect proportion of upper left, upper left, upper right and lower right dentition was different. In terms of oral health knowledge, the knowledge rate highest topic respectively to the correct number of brushing your teeth, bleeding gums self treatment, the tooth is how to deal with, a total of 27 cases of right, the accuracy was 54%, the lowest rate of health knowledge mastering subjects respectively to eliminate bad breath, prevention of dental caries, regular check teeth cycle, etc., a total of 41 cases of wrong. The error rate was 82%. In terms of behavioral awareness and dentition loss, 31 (62%) of the 50 subjects brushed their teeth less than or equal to once a day. There were 27 cases (54%) who brushed teeth ≥2 times a day. 33 cases (66%) had toothbrushing time ≤2min each time. There were 16 cases (32%) with daily brushing time ≥3min. As can be seen from the above data, the dentition loss rate of subjects brushing teeth ≤1 times a day was higher than that of subjects brushing teeth ≥2 times a day, and the comparison of data information between the two was statistically significant (P < 0.05). The tooth loss rate of subjects with daily brushing time ≤2min was higher than that of subjects with brushing time ≥3min, and the comparison of data information between them was statistically significant (P < 0.05). Conclusion: the elderly oral teeth in Mudanjiang city is relatively poor, much less than with the elderly oral health knowledge, weak consciousness of behavior and so on, needs medical department combining with community publicity of oral health knowledge, encourage the elderly to master all kinds of daily oral care and disease prevention methods, to further promote oral health.展开更多
Objective: to investigate the family attention of children with bad oral habits in Mudanjiang area. Methods: questionnaires were distributed from kindergartens, primary school students and parents in Mudanjiang area t...Objective: to investigate the family attention of children with bad oral habits in Mudanjiang area. Methods: questionnaires were distributed from kindergartens, primary school students and parents in Mudanjiang area to evaluate the current awareness of oral health and family concern of children and parents. Results: in this survey, the main proportion of children aged 7-9 years old, accounting for 49%. The number of children with bad oral habits in the family was 240, accounting for 60%. The number of children who thought that there were 2 pairs of teeth in life was 337, accounting for 84.25%. The number of people who thought that the protection of teeth was for the sake of tooth health was 234, accounting for 58.5%. Most children have the right brushing method and the brushing time meets the requirements. It is clear that eating sugar food will increase the possibility of caries. Moreover, most parents pay attention to the oral problems of children and will take the initiative to lead the children to the hospital for examination. Conclusion: according to the investigation on the bad oral habits of children in Mudanjiang area, it is found that some children and their parents have little understanding of oral knowledge, so it is necessary to strengthen the popularization of knowledge.展开更多
Objective: to investigate the correlation between psychological factors and the incidence of recurrent oral ulcer among college students in Mudanjiang area. Methods: 80 cases of recurrent oral ulcer were randomly sele...Objective: to investigate the correlation between psychological factors and the incidence of recurrent oral ulcer among college students in Mudanjiang area. Methods: 80 cases of recurrent oral ulcer were randomly selected from full-time college students in Mudanjiang area, the incidence of recurrent oral ulcer in college students was investigated by questionnaire, the psychological factors affecting the occurrence of the disease were evaluated, and the appropriate psychological intervention was carried out to compare the effects before and after the intervention. Results: 98.75% of the students had different stress events in the course of disease, among which learning pressure was the dominant one. After the intervention, the score of symptom scale was lower than that before the intervention, P < 0.05. Before and after the intervention, there was no difference in P psychosis and L dissimulation tendency, P > 0.05. After the intervention, N neuroticism was lower than before, and E inside and outside tendency was higher than before, P < 0.05. Conclusion: psychological factors are closely related to the occurrence of recurrent oral ulcer, and effective psychological intervention should be taken for college students in Mudanjiang area to reduce the incidence of recurrent oral ulcer.展开更多
The Jiamusi and Songnen blocks converged in the easternmost segment of the Central Asian Orogenic Belt as a result of the subduction and subsequent closure of the Mudanjiang oceanic plate during the Permian-Jurassic.T...The Jiamusi and Songnen blocks converged in the easternmost segment of the Central Asian Orogenic Belt as a result of the subduction and subsequent closure of the Mudanjiang oceanic plate during the Permian-Jurassic.The Mudanjiang suture zone was later directly affected by subductions of the Paleo-Pacific plate and Pacific plate and is therefore an ideal place to study the subduction polarity and later transformation of a paleo-suture zone.Using three-dimensional inversion of magnetotelluric data collected along a 160-km-long profile across the Mudanjiang suture zone,we established a resistivity model of the suture zone and adjacent area.Our results reveal the subduction polarity and subduction trace of the Mudanjiang oceanic plate and provide geoelectrical evidence for reactivation of the Mudanjiang suture zone induced by the(Paleo-)Pacific plate subduction.The suture zone shows a complex conductive structure.The west-dipping crustal-scale conductor beneath the Songnen-Jiamusi collision zone represents the fossil subduction zone and indicates the westward subduction polarity of the Mudanjiang oceanic plate.Furthermore,the Mudanjiang fault identified by surface geology does not fully represent the deep structure of the Mudanjiang suture zone.The definition of the suture zone should be extended to the whole conductive region with a lateral extent of~70 km.Solid conductive minerals beneath the arc in front of the subduction zone were exhumated up from deep to the upper crust.The“chimney”-shaped conductor connected with the mantle represents the intrusive pathways of mantle-derived materials,suggesting that the Mudanjiang suture zone was reactivated by subductions of the Paleo-Pacific plate and Pacific plate,leading to remelting of the cooled and crystallized materials in the pathways.Therefore,subduction of the(Paleo-)Pacific plate destroyed the lithospheric structure of the paleo collision zone in the eastern segment of the Central Asian orogenic belt,and the large-scale crustal conductor beneath the suture zone reflects reactivation of the paleo-suture zone.展开更多
佳木斯地块和松嫩—张广才岭地块是中亚造山带东段的两个相邻微陆块,二者在晚古生代至早中生代的拼合历史与牡丹江洋的形成与演化过程密切相关。黑龙江杂岩被认为保留着牡丹江洋的俯冲增生痕迹,是一套混有解体蛇绿岩残块,并经历了蓝片...佳木斯地块和松嫩—张广才岭地块是中亚造山带东段的两个相邻微陆块,二者在晚古生代至早中生代的拼合历史与牡丹江洋的形成与演化过程密切相关。黑龙江杂岩被认为保留着牡丹江洋的俯冲增生痕迹,是一套混有解体蛇绿岩残块,并经历了蓝片岩相变质作用的构造混杂岩(董申保,1989;Zhao Liangliang et al.,2024)。黑龙江杂岩的形成时代一直存在争议,包括早古生代、晚三叠世—中侏罗世、侏罗纪及早白垩世等不同认识;变质年龄集中于早—中侏罗世,关于杂岩内岩石变形的厘定及构造期次的划分仍缺少系统的研究和总结。展开更多
基金the support of Yajing Mao and Lingquan Zhao during the preparation of the manuscript.This research was financially supported by the National Natural Science Foundation of China(No.U2244206).
文摘The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt(CAOB)to the onset of the Paleo-Pacific subduction.In this study,we investigate epidote-ferroglaucophane(Ep-Fgl)and garnet-ferrobarroisite(Grt-Fbrs)schists from the Yilan area of the Heilongjiang Complex through petrological,mineralogical,thermodynamic modelling,whole-rock geochemical,and geochronological analyses.The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane+epidote+chlorite+clinopyroxene+phengite+titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495℃.On the other hand,the Grt-Fbrs schists exhibit a peak assemblage of garnet+glaucophane/ferroglaucophane+lawsonite+chlorite+phengite+rutile±clinopyroxene±titanite,deriving peak P-T conditions of 16.4-18.3 kbar and 457-475℃.Both types of schist record similar clockwise P-T paths,with three metamorphic stages:a peak epidote-to-lawsonite blueschist-facies stage,a post-peak decompression stage in the epidote amphibolite-facies,and a late greenschist-facies overprint stage.The Ep-Fgl schists display alkaline OIB-like geochemical affinities,while the Grt-Fbrs schists show tholeiitic MORB-like characteristics,suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust.Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276±1 Ma and 280±1 Ma,whereas zircon of Grt-Fbrs schists document protolith ages of 249±2 Ma and 248±2 Ma,indicating that the Mudanjiang Ocean existed since at least the early Permian.Reconstruction of the metamorphic P-T evolution,combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic,driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.
文摘In recent years, with the rapid increase of economy, improvement of national life standard and dramatic expansion of urbanization, the paper has pointed out that rural area has lost its feature gradually and rural landscape appears to be fuzzy. In view of this, survey and analysis have been conducted on rural landscape cultural types and features of Mudanjiang City, laying a foundation to the exploration and effective expression of rural landscape culture of Mudanjiang City during the planning and design of rural landscape. It hopes to protect original rural landscape connotation and regional feature, make it better adapt to the requirement of modern development, and provide a theoretical reference for the advancement of rural landscape planning in China.
文摘Objective: to investigate and analyze the oral dentition of middle-aged and old people in Mudanjiang city, and put forward measures to improve the oral health of middle-aged and old people. Results: in 50 cases, 37 cases had complete dentition, among which the defect proportion of upper left, upper left, upper right and lower right dentition was different. In terms of oral health knowledge, the knowledge rate highest topic respectively to the correct number of brushing your teeth, bleeding gums self treatment, the tooth is how to deal with, a total of 27 cases of right, the accuracy was 54%, the lowest rate of health knowledge mastering subjects respectively to eliminate bad breath, prevention of dental caries, regular check teeth cycle, etc., a total of 41 cases of wrong. The error rate was 82%. In terms of behavioral awareness and dentition loss, 31 (62%) of the 50 subjects brushed their teeth less than or equal to once a day. There were 27 cases (54%) who brushed teeth ≥2 times a day. 33 cases (66%) had toothbrushing time ≤2min each time. There were 16 cases (32%) with daily brushing time ≥3min. As can be seen from the above data, the dentition loss rate of subjects brushing teeth ≤1 times a day was higher than that of subjects brushing teeth ≥2 times a day, and the comparison of data information between the two was statistically significant (P < 0.05). The tooth loss rate of subjects with daily brushing time ≤2min was higher than that of subjects with brushing time ≥3min, and the comparison of data information between them was statistically significant (P < 0.05). Conclusion: the elderly oral teeth in Mudanjiang city is relatively poor, much less than with the elderly oral health knowledge, weak consciousness of behavior and so on, needs medical department combining with community publicity of oral health knowledge, encourage the elderly to master all kinds of daily oral care and disease prevention methods, to further promote oral health.
文摘Objective: to investigate the family attention of children with bad oral habits in Mudanjiang area. Methods: questionnaires were distributed from kindergartens, primary school students and parents in Mudanjiang area to evaluate the current awareness of oral health and family concern of children and parents. Results: in this survey, the main proportion of children aged 7-9 years old, accounting for 49%. The number of children with bad oral habits in the family was 240, accounting for 60%. The number of children who thought that there were 2 pairs of teeth in life was 337, accounting for 84.25%. The number of people who thought that the protection of teeth was for the sake of tooth health was 234, accounting for 58.5%. Most children have the right brushing method and the brushing time meets the requirements. It is clear that eating sugar food will increase the possibility of caries. Moreover, most parents pay attention to the oral problems of children and will take the initiative to lead the children to the hospital for examination. Conclusion: according to the investigation on the bad oral habits of children in Mudanjiang area, it is found that some children and their parents have little understanding of oral knowledge, so it is necessary to strengthen the popularization of knowledge.
文摘Objective: to investigate the correlation between psychological factors and the incidence of recurrent oral ulcer among college students in Mudanjiang area. Methods: 80 cases of recurrent oral ulcer were randomly selected from full-time college students in Mudanjiang area, the incidence of recurrent oral ulcer in college students was investigated by questionnaire, the psychological factors affecting the occurrence of the disease were evaluated, and the appropriate psychological intervention was carried out to compare the effects before and after the intervention. Results: 98.75% of the students had different stress events in the course of disease, among which learning pressure was the dominant one. After the intervention, the score of symptom scale was lower than that before the intervention, P < 0.05. Before and after the intervention, there was no difference in P psychosis and L dissimulation tendency, P > 0.05. After the intervention, N neuroticism was lower than before, and E inside and outside tendency was higher than before, P < 0.05. Conclusion: psychological factors are closely related to the occurrence of recurrent oral ulcer, and effective psychological intervention should be taken for college students in Mudanjiang area to reduce the incidence of recurrent oral ulcer.
基金supported by the National Natural Science Foundation of China(Grant Nos.42230303,41504076,41874125)the China Geological Survey Project(Grant No.DD20190010)the Fundamental Research Funds for the Central Universities(Grant No.JLUXKJC2021ZZ11).
文摘The Jiamusi and Songnen blocks converged in the easternmost segment of the Central Asian Orogenic Belt as a result of the subduction and subsequent closure of the Mudanjiang oceanic plate during the Permian-Jurassic.The Mudanjiang suture zone was later directly affected by subductions of the Paleo-Pacific plate and Pacific plate and is therefore an ideal place to study the subduction polarity and later transformation of a paleo-suture zone.Using three-dimensional inversion of magnetotelluric data collected along a 160-km-long profile across the Mudanjiang suture zone,we established a resistivity model of the suture zone and adjacent area.Our results reveal the subduction polarity and subduction trace of the Mudanjiang oceanic plate and provide geoelectrical evidence for reactivation of the Mudanjiang suture zone induced by the(Paleo-)Pacific plate subduction.The suture zone shows a complex conductive structure.The west-dipping crustal-scale conductor beneath the Songnen-Jiamusi collision zone represents the fossil subduction zone and indicates the westward subduction polarity of the Mudanjiang oceanic plate.Furthermore,the Mudanjiang fault identified by surface geology does not fully represent the deep structure of the Mudanjiang suture zone.The definition of the suture zone should be extended to the whole conductive region with a lateral extent of~70 km.Solid conductive minerals beneath the arc in front of the subduction zone were exhumated up from deep to the upper crust.The“chimney”-shaped conductor connected with the mantle represents the intrusive pathways of mantle-derived materials,suggesting that the Mudanjiang suture zone was reactivated by subductions of the Paleo-Pacific plate and Pacific plate,leading to remelting of the cooled and crystallized materials in the pathways.Therefore,subduction of the(Paleo-)Pacific plate destroyed the lithospheric structure of the paleo collision zone in the eastern segment of the Central Asian orogenic belt,and the large-scale crustal conductor beneath the suture zone reflects reactivation of the paleo-suture zone.
文摘佳木斯地块和松嫩—张广才岭地块是中亚造山带东段的两个相邻微陆块,二者在晚古生代至早中生代的拼合历史与牡丹江洋的形成与演化过程密切相关。黑龙江杂岩被认为保留着牡丹江洋的俯冲增生痕迹,是一套混有解体蛇绿岩残块,并经历了蓝片岩相变质作用的构造混杂岩(董申保,1989;Zhao Liangliang et al.,2024)。黑龙江杂岩的形成时代一直存在争议,包括早古生代、晚三叠世—中侏罗世、侏罗纪及早白垩世等不同认识;变质年龄集中于早—中侏罗世,关于杂岩内岩石变形的厘定及构造期次的划分仍缺少系统的研究和总结。
