Study on north boundary of subtropical zone in Funiu Mountain according to soil geochemistry

The boundary between subtropical zone and temperate zone is not only important in physical geography, but also attractive in agricultural production. Seven soil profiles studied in this paper are placed along the southern slope of Funiu Mountain at different heights above sea level. Many compositions and properties of these soils have been determined in laboratory. In this paper, the laws of migration and accumulation of soil materials on the southern slope of Funiu Mountain are discussed first, then the division of the boundary between subtropical zone and temperate zone in this area according to soil geochemistry is discussed with qualitative methods and mathematical classification method in which twelve selected indexes such as K m , Saf, Ba, β, Feo/Fet, Mno/Mnt and so on are used. The result indicates that the boundary between subtropical zone and temperate zone on the southern slope of Funiu Mountain is about 950 m above sea level.

Element cycling in the dominant plant community in the Alpine tundra zone of Changbai Mountains, China

Element cycling in the dominant plant communities including Rh. aureum, Rh. redowskianum and Vaccinium uliginosum in the Alpine tundra zone of Changbai Mountains in northeast China was studied. The results indicate that the amount of elements from litter decomposition was less than that of the plant uptake from soil, but that from plant uptake was higher than that in soil with mineralization process released. On the other hand, in the open system including precipitation input and soil leaching output, because of great number of elements from precipitation into the open system, the element cycling(except N, P) in the Alpine tundra ecosystem was in a dynamic balance. In this study, it was also found that different organ of plants had significant difference in accumulating elements. Ca, Mg, P and N were accumulated more obviously in leaves, while Fe was in roots. The degree of concentration of elements in different tissues of the same organ of the plants also was different, a higher concentration of Ca, Mg, P and N in mesophyll than in nerve but Fe was in a reversed order. The phenomenon indicates (1) a variety of biochemical functions of different elements, (2) the elements in mesophyll were with a shorter turnover period than those in nerve or fibre, but higher utilization rate for plant. Therefore, this study implies the significance of keeping element dynamic balance in the alpine tundra ecosystem of Changbai Mountains.

RS AND GIS-BASED FOREST FIRE RISK ZONE MAPPING IN DA HINGGAN MOUNTAINS

The Da Hinggan Mountains is one of the most important forest areas in China, but forest fire there is also of high frequency. So it is completely necessary to map forest fire risk zones in order to effectively manage and protect the forest resources. Two forest farms of Tuqiang Forest Bureau (53°34′-52°15′N,124°05′-122°18′E) were chosen as typical areas in this study. Remote sensing (RS) and Geographic Information System (GIS) play a vital role and can be used effectively to obtain and combine different forest-fire-causing factors for demarcating the forest fire risk zone map. Forest fire risk zones were described by assigning subjective weights to the classes of all the coverage layers according to their sensitivity to fire, using the ARC/INFO GIS software. Four classes of forest fire risk ranging from low to extremely high were generated automatically in ARC/INFO. The results showed that about 60.33% of the study area were predicted to be upper moderate risk zones, indicating that the forest fire management task in this area is super onerous. The RS and GIS-based forest fire risk model of the study area was found to be highly compatible with the actual fire-affected sites in 1987. Therefore the forest fire risk zone map can be used for guidance of forest fire management, and as basis for fire prevention strategies.

RELATIONSHIP BETWEEN P-T CONTITIONS OF TWO PHASES OF TAN-LU STRIKE-SLIP SHEAR ZONES AND DELAMINATION OF OROGENIC BELTS ON THE EASTERN MARGIN OF THE DABIE MOUNTAINS

The Tan-Lu fault zone joins the Dabie Mountains on its eastern margin, and offsets the Dabie and Sulu orogenic belts sinistrally for about 500 km. On the basis of calculation of temperature and pressure experienced by the two phases of the fault zone as well as the thermo-chronological information on mylonite from the earlier and later Tan-Lu fault zones on the eastern margin of the Dabie Mountains, this paper discusses the delamination history and uplifting magnitudes of the Dabie Mountains from earlier Jurassic to earlier Cretaceous. From mineral assemblages, mineral deformation and muscovite-chlorite geothermometry calculation, it is known that the temperature experienced by the two phases of Tan-Lu fault zones are between 400℃ and 450℃, and the confining pressures are between 0.25Gpa and 0.36GPa for the earlier shear zones and 0.24-0.39GPa for the late shear zones. According to the geobarometry of Si-in-phengite and by considering shear heating and tectonic over-pressure, it is concluded that the maximum formation depths for the two phases of the ductile shear zones are not more than 12 km. Differential formation depths for the two phases of shear zones are 1-2 km at most. At about 190 Ma and 128 Ma, the Tan-Lu fault zone experienced two phases of cooling events. During this period, the eastern margin of the Dabie Mountains experienced a tectonic calm period and no uplifting. According to information from the Tan-Lu fault zone, the uplifting magnitudes of the Dabie orogenic belts are not more than 12 km during the earlier Cretaceous.

THE CHARACTERISTICS AND VERTICAL ZONE SPECTRUM OF NATURAL DISASTERS IN THE TIANSHAN MOUNTAINS, XINJIANG

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Morphological Characteristics and Environmental Implications of Phytoliths in Topsoils from Different Vegetation Zones on Northern Slope of Changbai Mountains,China

The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline.

Late Quaternary Activity of the Central-North Segment of the Taihang Mountains Piedmont Fault Zone

The location and late Quaternary activity of the Central-North Segment of the Taihang Mountains Piedmont fault zone have been studied by shallow seismic survey and combined drill exploration.Our results show that the Baoding-Shijiazhuang fault and the Xushui fault were active in the late Pleistocene,but the south Xushui fault has been inactive since the late Pleistocene.The maximum magnitude of potential earthquake of the faults is 6.0.

Tectonic implication of geomorphometric analyses along the Saravan Fault: evidence of a difference in tectonic movements between the Sistan Suture Zone and Makran Mountain Belt

In this paper, remote sensing techniques,as well as field studies, have been used to investigate the geomorphological processes and landscape evolution along the Saravan Fault, SE Iran to highlight how topographic features were influenced by active tectonics. Quantitative geomorphic analysis was carried out using mountain-front sinuosity(Smf),valley floor width-valley height ratio(Vf), drainage basin asymmetry factor(Af), Hypsometric integral(Hi), drainage basin shape index(Bs), mean axial slope of channel(MASC), standard deviation of topography(STD) and index of active tectonic(Iat).Remote sensing techniques, as well as field studies revealed that the Saravan Fault have three parts trending N-S, NW-SE, and E-W. Obtained results show that basins with high Iat index are located at where the strike of the Saravan Faults changes and where several strike-slip faults are crossed the Saravan fault.

Spatial variations of Pb in the vertical zone of the soil-plant system in the Changbai Mountain National Nature Reserve

The characteristics of vertical and horizontal variations of lead element(Pb) in soil plant system of vertical zone in Changbai Mountain National Nature Reserve(CNNR) were studied. The results showed that Pb concentrations in soils of vertical zone are all above 25 mg/kg, and the average Pb concentration of each soil zone negatively correlates its degree of variation, i.e. brown coniferous forest soil zone has the lowest average Pb concentration of four soil zones, and the highest horizontal variation; however, mountain soddy forest soil has the highest average Pb concentration, and the lowest horizontal variation; the average concentration of plant Pb of each plant zone is lower than the worldwide average level of Pb in plant(Clarke), respectively, and plant Pb content order is consistent with soil Pb content order, but their horizontal variations are different from those in soil zones, the variation of mountain tundra forest zone is highest, but Betula ermanii forest zone the lowest. Vertical variation of plant Pb is obviously higher than that in soils with variation coefficient of 89.76%; the enrichment capability of plant for Pb is depended on the plant types and the different organs of plant; parent material and parent rock, pH values, soil organic matter and soil particle fraction etc. are the main factors influencing variations of Pb content in soil plant system of vertical zone in CNNR.

Analysis on the Observation Data of Three Profiles across the Qilian Mountain-Haiyuan Fault Zone

由分析 GPS，铺平并且从 Minle， Huazangsi 和 Shagouhe 的严肃观察数据在 2005 期间介绍 Qilian Mountain-Haiyuan 差错到对面 - 2009，这些数据的变化和在不同时间的主要差错的活动特征被获得。Changma-Erbo， Maomaoshan， Zhunglanghe 和 Haiyuan 指责的结果表演在最近的年里是活跃的。在垂直排水量和活动严肃数据之间的关系被分析，并且结果表明严肃变化主要由于集体转移。水平运动速度的方向几乎沿着差错的 GPS 观察表演的结果在 2006 罢工 - 2007 当水平速度在 2007 从差错方向背离了时 - 2008，由增加的东方排水量描绘了。在连续观察的 N 和 E 坐标值的时间系列上的线性趋势的移动之上的进一步的分析在三侧面附近中国的外壳的运动观察网络驻扎表明 Wenchuan 地震在 2007 在观察上有效果 - 2008。在 2008 比较重力的变化 - 2009 与 Bouguer 严肃异例背景，我们发现 Minle 侧面附近的区域在调整和恢复的阶段，当异例完全没在 Huazangsi 和 Shagouhe 侧面附近被恢复时。

Zircon Dating and Geological Implications of Granitic Gneiss in the Metamorphic Zone of Gaoligong Mountains in Western Yunnan, China

The general classification of intermediate-acid intrusive rocks in the metamorphic zone of Gaoligong Mountains as one of the metamorphic terranes of Proterozoic Gaoligong Mountains is problematic regarding the intrusion stage and age, as well as the subsequent metamorphism and deformation. In this study, we investigated granitic gneiss in the metamorphic zone of Gaoligong Mountains based on the 1：50,000 regional geological survey of Qushi Street （2011-2013） and SHRIMP U-Pb zircon geochronology. Results showed that the SHRIMP U-Pb zircon dating of granitic gneiss ranged from 163.5±5.7 Ma to 74.0±2.0 Ma. Thus, the granitic gneiss was grouped into orthometamorphic rocks （metamorphic intrusions）. The dating data of granite rocks associated with intense metamorphism and deformation were divided into three groups, 163.5±5.7 to 162.3±3.1 Ma, 132.2-101.0 Ma and 99.4±3.5-74.0±2.0 Ma, which respectively represented three independent geologic events including an important magma intrusion with superimposed metamorphic effects in the late Middle Jurassic, regional dynamic metamorphism and superimposed reformation of fluid action in the early Cretaceous, and dynamic metamorphism dominated by ductile shear and metamorphism starting from the late Cretaceous.

Study on rupture zone of the M=8.1 Kunlun Mountain earthquake using fault-zone trapped waves

The observation of the fault-zone trapped waves was conducted using a seismic line with dense receivers across surface rupture zone of the M=8.1 Kunlun Mountain earthquake. The fault zone trapped waves were separated from seismograms by numerical filtering and spectral analyzing. The results show that: a) Both explosion and earthquake sources can excite fault-zone trapped waves, as long as they locate in or near the fault zone; b) Most energy of the fault-zone trapped waves concentrates in the fault zone and the amplitudes strongly decay with the distance from observation point to the fault zone; c) Dominant frequencies of the fault-zone trapped waves are related to the width of the fault zone and the velocity of the media in it. The wider the fault zone or the lower the velocity is, the lower the dominant frequencies are; d) For fault zone trapped waves, there exist dispersions; e) Based on the fault zone trapped waves observed in Kunlun Mountain Pass region, the width of the rupture plane is deduced to be about 300 m and is greater than that on the surface.

2022—2023年四川泸定M_(S)6.8、M_(S)5.0和M_(S)5.6地震序列的发震构造及成因

四川泸定2022年9月5日发生M_(S)6.8强震,随后10月22日和2023年1月26日又分别发生M_(S)5.0和M_(S)5.6强余震,主震和两次强余震的震中相距仅几公里却有着截然不同的震源机制解,因此,探究三者的发震构造、联系及成因至关重要.本研究利用国家地震台网记录到的这三次地震序列的连续波形数据及震相资料进行双差重定位,并进一步采取CAP波形反演方法和P波初动极性反演方法获得研究区M_(L)2.5+的79个余震震源机制解.结果显示,主破裂沿鲜水河断裂磨西段,破裂彻底,余震活动性不高.沿主断裂分布的余震具有明显的分段特征,断层近直立且西北浅东南深.主震及磨西段大部分余震均为走滑机制,是典型的印度—欧亚板块挤压旋转造成鲜水河走滑断裂带应力失稳触发的强震活动.发生在贡嘎山地区的余震是M_(S)6.8主震触发的震群活动,震级水平不高,分布弥散,并没有触发与主断裂共轭的燕子沟、海螺沟和磨子沟次级断裂,而是触发了与主断裂近平行的次级隐伏断裂——贡嘎山断裂.M_(S)5.0和M_(S)5.6两次强余震均发生在该次级隐伏断裂上,断层倾角40°~50°且震源深度较浅.贡嘎山地区拉张型地震活动明显不同于走滑型为主的鲜水河断裂带,可能是印度—欧亚板块挤压旋转作用下贡嘎山快速隆升而地表快速剥离导致局部因重力卸载而垮塌造成的,M_(S)6.8主震有明显的触发作用.三次泸定强震的发生,释放了磨西段及西侧贡嘎山地区部分应力,但并未改变"Y"字形交汇区强震发生的可能性.

大别山区茶树春霜冻时空演变规律及风险区划

基于大别山区35个国家气象观测站1971-2020年逐日气象资料,利用趋势面插值和ArcGIS技术,分析大别山区茶树春霜冻时空分布特征,依据自然灾害风险理论,选取致灾因子危险性、孕灾环境暴露性、承载体脆弱性和防灾减灾能力等评价因子,利用加权综合评价法构建茶树春霜冻灾害综合风险评估模型,并基于ArcGIS技术开展风险区划。结果表明:(1)1971-2020年大别山区不同等级春霜冻发生日数均显著下降,发生总日数及轻度、中度、重度春霜冻发生日数均值分别为9.6、5.2、3.0和1.4d,气候倾向率分别为-1.45、-0.61、-0.54和-0.30d·10a-1;春霜冻发生日数与海拔高度和纬度呈正相关,大别山区北部春霜冻发生日数较南部下降趋势更明显。(2)大别山区茶树春霜冻高、中和低风险区分别占研究区总面积的16.67%、41.88%和41.45%;高风险区主要位于金寨县、岳西县、霍山县和英山县等海拔600m以上高山区域,信阳市及零星阴坡(北坡)地带;中风险区主要位于海拔低于600m的山区及大别山北麓部分低海拔地区,零星分布在南麓阴坡(北坡)低海拔地区;低风险区主要位于大别山南麓低海拔地区,零星分布在北麓阳坡(南坡)低海拔地区。大别山区茶树春霜冻风险精细化评估可为优化茶产业布局、提升防灾减灾能力提供参考。

山地城市国土空间生态保护修复分区研究——以重庆为例

科学划定生态保护修复分区是国土空间生态保护修复规划的基础,是制定差别化的生态保护修复政策的主要依据。本文以重庆为例,围绕国土空间生态保护和生态修复及人类活动的现实需求,在全面分析国土空间生态现状和生态功能状况评估的基础上,遵循自然地理格局和生态系统完整性,探索国土空间生态保护修复分区方法及思路。研究表明:(1)山、水等自然资源天然地将全市划分为两大本底空间。一是大巴山、巫山—七曜山、武陵山、大娄山为主体的自然生态空间,自然资源丰富,生态功能突出;二是以平行岭谷、方山丘陵为主体的人类活动空间,地势平坦,耕作条件好,是主要的城镇建设区和农业发展区。(2)盆周山地和海拔较高的山脉人类活动强度低,生态敏感性高,服务功能水平较高,退化不明显,恢复力处于高位水平。中心城区、渝西地区人类活动强烈,生态系统退化明显,生态服务功能水平较低,恢复力不强。(3)根据生态现状和生态系统状况评估的差异性,综合自然、社会、经济复合需求,综合划定了“一核四片”生态保护修复分区,并提出分区生态保护修复治理方向建议。

新疆且末县青塔山岩体地球化学特征及其地质意义

青塔山岩体位于东昆仑山西部,岩体的形成时代、环境、岩石类型尚存在争议,对于其成岩的物理化学条件和源区特征的研究程度较低。在系统开展岩石学和岩相学研究的基础上,对黑云母、斜长石和角闪石等主要造岩矿物进行了成分分析,厘定其成岩的物理化学条件,进一步约束岩石成因。研究表明:青塔山岩体的岩性为英云闪长岩,脉体岩性为石英闪长岩;岩体中斜长石为中长石和拉长石,黑云母为镁质黑云母,角闪石为镁角闪石,斜长石发育反环带,应为岩浆混合所致;黑云母的结晶温度为684~693℃,结晶压力为(1.86~2.01)×10^(8) Pa,平均值为1.92×10^(8) Pa,对应结晶深度为6.90~7.46 km,平均7.12 km,属于中深成相。岩体形成时氧逸度较低,为-17.34~-17.04。矿物化学特征显示,青塔山岩体中黑云母的物质来源为钙碱性造山岩套,其形成与壳幔混源岩浆有关。研究成果可为研究青塔山地区晚三叠世—早侏罗世岩浆演化历史提供依据。

太行山东南麓断裂带水文地球化学特征及水热成因模式

太行山东南麓断裂带发育,赋存丰富的中低温地热资源,然而,该地区深部地热水的水热成因模式依然不清楚。通过55组地热水和38组浅层地下水的水化学组分特征,研究离子组分来源及其运移规律,并借助同位素特征分析地热水补给来源,在此基础上分析深部热储的水岩平衡状态、热储温度和热循环深度。结果表明:研究区属对流—传导复合型地热系统,地热水整体处于氧化环境,离子组分以HCO_(3)^(-)和Na^(+)为主,主要受盐岩和碳酸盐岩等矿物的溶解及阳离子交替吸附作用控制;地热水的补给高程为1010~1153m,表明地热水补给区位于太行山东南麓西部的太行山地区;地热水循环深度范围为1125~4468 m;混合比例法估算汤阴断陷深层热储温度达到110~160℃,而汤阴断陷东部的内黄凸起地区为80~110℃,二者热储温度差别源自汤阴断陷两侧深切地幔的汤东、汤西深大断裂导热导水条件良好,以及内黄凸起的基岩埋深较浅,上伏盖层薄,热能更容易散失。本研究揭示了太行山东南麓地热系统的水文地球化学特征和水热成因模式,为该区地热资源开发利用提供重要依据。

山江海耦合关键带生态系统服务价值时空变化及其权衡研究

[目的]量化和分析山江海耦合关键带生态系统服务价值及时空变化,有助于深入了解其生态系统服务现状,进而阐明山江海耦合关键带生态服务之间的权衡/协同关系,对提高生态系统服务之间相互作用的认识,促进区域全面可持续发展和生态环境保护与修复具有重要意义。[方法]基于1990—2020年7期土地利用数据及结合修订后的当量因子表,运用网格法、地理加权回归等方法分析了山江海耦合关键带1990—2020年ESV时空变化和各项生态系统服务相互关系及其空间分异特征。[结果]1990—2020年山江海耦合关键带总ESV从788.55亿元增加至792.30亿元,增幅为0.48%,林地、耕地、水域地类ESV较高,为区内总ESV主要贡献因子,建设用地ESV较低,ESV在空间上呈现从西北向东南降低的趋势;1990—2020年各项生态系统服务相互关系以协同关系为主,约占85.45%,其中权衡高值区主要分布在山江海耦合关键带中部及南部地区,低值区主要分布在百色市喀斯特山区;协同低值区主要分布在人口密集、人类活动频繁、经济较为发达的市县级城区及沿海地区。[结论]1990—2020年山江海耦合关键带生态系统服务整体协调且保持动态平衡,食物生产活动会影响其他生态服务的能力,未来地方应严格把控生产活动开发边界,注重对生产地区的环境保护与修复。

基于人地耦合的湖南仙岳山省级森林公园分区管理策略

为探索城市近郊保护地综合保护和管理办法,形成科学可持续的管理体系,本文以醴陵市城市近郊的湖南仙岳山省级森林公园为研究对象,基于ASTER GDEM高程数据(N27E113)对保护地进行空间划分,运用ArcGIS中网络分析、服务区构建、空间分析、重要度评价法分析园内道路、周边构筑物所带来的人类活动对保护地各区域的影响及其差异,评估保护地生态功能的服务可达性;基于人地耦合的视角,在50 m×50 m分辨率水平上,将保护地划分为5个功能区域并制定了针对性的管理策略。其中,森林生态系统保育区施行严格封闭管理,森林资源多样性保育区适当进行人为干预保育特色物种,城市森林景观区加强多层、多季相森林景观营造,管理挑战与生境保护区应加强边界管理并划定人为活动影响预警区,有的放矢地开展定期巡视;文化旅游区应适度开发人文、自然景观,促进社区与保护地间的良性循环。本研究在实现城市近郊保护地与城市社区良性互动的基础上,针对仙岳山省级森林公园各区域空间特征、功能及其与城市的关系提出一套科学、可行的管理策略及实现路径,为城市近郊自然保护地的管理工作提供参考。