关于《中国西南历史地理考释》研究方法的再思考

方国瑜先生是著名的历史学家,在西南边疆史地研究方面有开创性的贡献。从《中国西南历史地理考释》中可总结其历史地理考释的方法。方先生重视文献的参稽考索,将史源学方法运用于所搜集的史料,重视史源和史料流传,但又不局限于史料。他紧密结合历史实际,运用马克思主义历史唯物主义的方法,从每一个时期、每一个地区的具体情况来阐释具体历史活动,根据地理环境、政治区划的演变来考释地名。

经世致用:蒋君章《西南经济地理》述评

《西南经济地理》是蒋君章有关西南地区经济地理研究的重要成果之一,主要包括西南五省的自然地理、农林畜产、工矿交通、人口民族、城市商贸等内容。蒋君章的西南经济地理研究是典型的“商业地理”研究模式,具有求真务实与经世致用的特征,而“经世致用”是认识近代中国地理学学术发展史的一把金钥匙。

打通西南“两洋”出海

背景材料：中国西南与缅甸有长达2000余公里的边境线。随着一系列通道项目的酝酿和建设，中国不久将打通西南，借道缅甸在印度洋上获得最便捷的出海口．形成东西两翼同时向“两洋”开放的格局。

基于《地理学报》创刊85年载文的中国西南地区之地理研究

西南地区以其独特的地理现象一直为国内外地理学者所关注。通过对《地理学报》创刊以来85年间西南地区研究的载文分析,可以管窥其研究脉络,并予未来研究以启示。结果表明:①232篇论文囊括了地理研究的若干主题,但以地貌、气象气候、综合自然地理和生态环境发文量最大,而城市、民族、交通、健康则关注较少;②研究经历了传统区域研究、任务带学科、承上启下和多元化发展4个阶段;③论文在数量和内容上的阶段性变化,既受国家时事格局影响,也受地理学科研究范式发展变化影响;④《地理学报》有关西南地区的载文具有很高的研究水平,无论是在学术视野还是研究方法手段上,区域的自然、人文、社会经济与生态环境等诸多研究都站在了学术研究前沿,代表了学界对西南地理的研究情况;⑤但西南地理研究论文增长速度远赶不上《地理学报》载文量增长,外来研究机构占比很大,本土力量弱;相较自然地理,人文地理研究也少而弱。可见,西南地理研究当从新区域地理视角重新审视这一地区传统与现代的碰撞、边界的接触与冲突和区际的联系与竞争,继续成就西南地区重要的地理意义。

Rocky Desertification Risk Zone Delineation in Karst Plateau Area:A Case Study in Puding County,Guizhou Province

Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantifed with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area （about 50.81%） was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.

Evaluation of regional tourism competitiveness:a case study of southwest China

Evaluation of regional tourism competitiveness has been a hot issue of tourism geography and regional economics in recent years. This study introduces system theory and Professor Porter's National Diamond Model into constructing the evaluation index system of regional tourism competitiveness, which includes four decisive factors, namely production factor, market, industry and support competitiveness. And by comprehensive use of subjective and objective methods like Principal Component Analysis (PCA) and Analysis Hierarchy Process (AHP) the appraised values were calculated. At the same time, the method was applied to dynamic demonstration analysis of the tourism competitiveness of the provinces in Southwest China from 2001 to 2005. The result shows that their tourism comprehensive competitiveness has distinct differences. The comprehensive competitiveness of Sichuan and Yunnan are better, Chongqing and Guangxi are in the middle, and Guizhou and Tibet are weak. According to the competitiveness ranks in 2001-2005, comprehensive, production factor, industry and support competitiveness changed a little and market competitiveness changed a lot. This competitive pattern has been made mostly because natural resource conditions and economic development levels of the provinces are very different and are difficult to be changed in a short period.

Large-Scale Dextral Strike-Slip Movement and Associated Tectonic Deformation Along the Red-River Fault Zone

Field investigation has revealed that the large-scale dextral strike-slip movement and the associated tectonic deformation along the Red River fault zone have the following features: geometrically, the Red River fault zone can be divided into three deformation regions, namely, the north, central and south regions. The north region lies on the eastern side of the Northwest Yunnan extensional taphrogenic belt, which is characterized by the 3 sets of rift-depression basins striking NNW, NNE and near N-S since the Pliocene time, and on its western side is the Lanping-Yunlong compressive deformation belt of the Paleogene to Neogene; the deformation in the central region is characterized by dextral strike-slip or shearing. The east Yunnan Miocene compressive deformation belt lies on the eastern side of the fault in the south, and the Tengtiaohe tensile fault depression belt is located on its west. In terms of tectonic geomorphology, the aforementioned deformation is represented by basin-range tectonics in the north, linear faulted valley-basins in the central part and compressive (or tensional) basins in the south. Among them, the great variance in elevation of the planation surfaces on both sides of the Cangshan-Erhai fault suggests prominent normal faulting along the Red River fault since the Pliocene. From the viewpoint of spatial-temporal evolution, the main active portion of the fault was the southern segment in the Paleogene-Miocene-Pliocene, which is represented by “tearing” from south to north. The main active portion of the fault has migrated to the northern segment since the Pliocene, especially in the late Quaternary, which is characterized by extensional slip from north to southeast. The size of the deformation region and the magnitude of deformation show that the eastern plate of the Red River fault has been an active plate of the relative movement of blocks.

Determination of Water Saturation （SW%） by Using P-wave Velocities for Saturated Sandstone

The seismic velocities are strongly influenced by porosity and degree of water saturation, as well as other petrophysical properties, such as density and elastic properties of the rocks. In this paper, the saturation of water percentage for sandstones （SW%） has been calculated by mathematical equation, which is based on the relation between the seismic velocity of water to the seismic velocity obtained in the field （for p-wave velocity only）. The results of this equation which ranged between （30% to 100%） are connected with the results of seismic velocity-porosity relation for saturated sandstone through model, this model can be used for determining the porosity （Φ） and water saturation percentage （SW%） of the sandstones in the same time.

拉萨地块白垩纪固着蛤研究新进展

通过对拉萨地块白垩纪固着蛤进行修订和总结,共识别出7个固着蛤有效种,分别为:Rutonia bangonghuensis Yang et al.,1982,Auroradiolites biconvexus (Yang et al.,1982),Eoradiolites cf. hedini (Douville,1916),Magallanesia rutogensis Rao et al.,2015,Shajia tibetica Rao et al.,2019,Sellaea sp.和 Monopleura sp.。该固着蛤组合的时代为阿普特期(Aptian)晚期至阿尔布期(Albian),与同层产出的圆笠虫组合指示的时代相符。拉萨地块北部郎山组和南缘桑祖岗组所产出固着蛤组合可相互对比。通过对固着蛤组合的分析,饶馨等(Rao et al.,2015,2017,2019a)首次识别出了白垩纪中期亚洲西南部/太平洋生物古地理分区,其固着蛤类群以区域性属Auroradiolites和Horiopleura haydeni–Praecaprotina–Magallanesia演化谱系为特征型分子。

Heavy mineral assemblage characteristics and the Cenozoic paleogeographic evolution in southwestern Qaidam Basin

Based on the analysis of heavy mineral assemblages in Cenozoic southwestern Qaidam Basin, we found that different areas have variable heavy mineral assemblage characteristics, which suggested that there were two source areas--the Altyn Moun- tains and the Qimen Tagh-East Kunlun Mountains. In Ganchaigou-Shizigou-Huatugou （Area A）, which was mainly source from the Altyn Mountains, its heavy minerals were mainly composed of zircon, Ti-oxides, and wollastonite in the Paleocene- early Eocene and mainly of unstable minerals, especially amphibole, in the middle Eocene-Oligene. Since the late Oligocene- Miocene, the heavy minerals were still mainly unstable minerals, but the content of epidote increased and the content of am- phibole decreased. In Qigequan-Hongliuquan （Area B）, which was the mixed source from the Altyn Mountains and the Qimen Tagh-East Kunlun Mountains, its heavy minerals were mainly garnet, epidote, and amphibole. The source of Lticaotan- Dongchaishan-Kunbei （Area C） was mainly from the Qimen Tagh-East Kunlun Mountains, heavy minerals in the sediments in Area C were mainly zircon and Ti-oxides in Paleogene and garnet, epidote, and amphibole in Neogene. In Yuejin-Youshashan （Area D）, where the stable minerals and unstable minerals were present simultaneously, the heavy mineral assemblages was controlled by multi-direction source. The variation of heavy mineral assemblages in southwestern Qaidam Basin shows that Altyn Mountains was of low-lying topographic relief in Paleocene-early Eocene, and the rapid uplift of Altyn Mountains started from the middle Eocene. In Paleogene, the Altyn Tagh Fault had a slow strike-slip velocity, but the strike-slip velocity increased greatly since the late Oligocene, leading to a strike-slip displacement above 300 km since Neogene. Meanwhile, the Qimen Tagh-East Kunlun fault zone was under a stable tectonic stage in Paleogene with the Qimen Tagh Mountain being low- lying hills; since the late Oligocene, the fault zone started to activate and the Qimen Tagh Mountain began to uplift rapidly.

Neoproterozoic sedimentary facies and glacial periods in the southwest of Tarim Block

Based on the analysis of sedimentary facies and chemical index of alteration(CIA) in Nanhua and Ediacaran Systems in the southwest of Tarim Block,some features of glacial records in Neoproterozoic become more clear.Six sedimentary facies have been divided in the study area,including alluvial fan facies,lacustrine facies,glacial facies,littoral facies,neritic facies,and lagoonal facies,showing that this area underwent a process from continent to marine,with mainly littoral and neritic sedimentation.Two cold events have been recognized by analysis of CIA values in the study area,called Bolong and Yutang glaciation,respectively.They present as thick-layer tillite deposition in the Bolong Formation and thin-layer tillite deposition in the Yutang Formation,respectively.The Bolong glacial period in the study area can be correlated to the Yulmeinak glacial period in Aksu area,Tereeken glacial period in Qurugtagh area,and the Nantuo glacial period in South China,which is equivalent to the universally acknowledged Marinoan glacial period.The Yutang glacial period can be correlated to the Hankalchough glacial period in Qurugtagh,which is equivalent to Gaskers glaciation in Newfoundland.

Electrical conductivities of two granite samples in southern Tibet and their geophysical implications

There are clear differences in the electrical conductivities of the crustal granites of the Qinghai-Tibet Plateau.Because these granites are among the major rock types on the Qinghai-Tibet Plateau, it is very important to detect the electrical conductivity of granites under high temperatures and pressures to study the electrical conductivity structure of this area. Using impedance spectroscopy at a frequency range of 10.1–106 Hz, the electrical conductivity of the muscovite-granite collected from Yadong was investigated at a confining pressure of 1.0 GPa and temperatures ranging from 577 to 996 K, while the electrical conductivity of the biotite-granite collected from Lhasa was investigated at a pressure of 1.0 GPa and temperatures ranging from587 to 1382 K. The calculated activation enthalpies of the Yadong muscovite-granite sample is 0.92 eV in the low-temperature range(577–919 K) and 2.16 eV in the high-temperature range(919–996 K). The activation enthalpies of the Lhasa biotite-granite sample is 0.48 eV in the low-temperature range(587–990 K) and 2.06 eV in the high-temperature range(990–1382 K). The change in the activation enthalpies of the granites at different temperature ranges may be associated with the dehydration of the two samples. The electrical conductivities of the granite samples obtained in the laboratory using impedance spectroscopy correspond well with field observations conducted near the sampling points, both in terms of the actual conductivity values and the observed variations between the low-temperature and high-temperature regimes. This correlation of laboratory and field conductivities indicates that the conductivities of the crustal rocks in the two regions closely correspond to granite conductivities.We calculated the electrical conductivities of muscovite-granite and biotite-granite samples using the effective medium and HS boundary models. When applied to the crustal rocks of southern Tibet, the results of the geophysical conductivity profiles lie within the range of laboratory data. Thus, the electrical characteristics of the crustal rocks underlying the southern Qinghai-Tibet Plateau can largely be attributed to granites, with the large changes to high conductivities at increasing depths resulting from the dehydration of crustal rocks with granitic compositions.

Estimating the geographic range of a threatened shark in a data-poor region： Cetorhinus maximus in the South Atlantic Ocean

The distribution of the planktivorous basking shark Cetorhinus maximus is influenced by zooplankton abundance at small scales and temperature at medium scales in the North Atlantic. Here, we estimate the distribution of basking sharks on South Atlantic continental shelves, and the relative importance of chlorophyll concentration, as a proxy for zooplankton abun- dance, and temperature in determining habitat suitability for basking sharks at large scales. We used maximum entropy （MaxEnt） and maximum likelihood （MaxLike） species distribution modelling to test three hypotheses： the distribution of basking sharks is determined by （1） temperature, （2） chlorophyll concentration, or （3） both chlorophyll and temperature, while considering other factors, such as oxygen and salinity. Off South America, basking shark habitat included subtropical, temperate and cool-temperate waters between approximately 20°S and 55°S. Off Africa, basking shark habitat was limited to cool-temperate waters off Namibia and southern South Africa. MaxLike models bad a better fit than MaxEnt models. The best model included minimum chlorophyll concentration, dissolved oxygen concentration, and sea surface temperature range, supporting hypothesis 3. However, of all variables included in the best model, minimum chlorophyll concentration had the highest influence on basking shark distribution. Unlike the North Atlantic distribution, the South Atlantic distribution of basking sharks includes subtropical and cool-temperate waters. This difference is explained by high minimum chlorophyll concentration off southern Brazil as compared to North Atlantic subtropical areas. Observations in other regions of the world support this conclusion. The highest habitat suitability for basking sharks is located close to nearshore areas that experience high anthropogenic impact [Current Zoology 61 （5）： 811-826, 2015].