祁连山—河西走廊黑河流域地貌特征及其构造意义

采用定量化的地貌因子研究区域构造活动及其演化已成为构造地貌学的一种常用手段。祁连山—河西走廊位于青藏高原东北部边缘,是高原向NE方向挤压扩展的前缘部位,该区河流水系的地貌发育过程记录了高原隆升与挤压扩展及其气候环境效应的重要信息。位于祁连山北部山前的黑河流域向N穿过河西走廊和北山地区,其河流地貌的发育与祁连山的构造隆升直接相关。基于诸多地貌因子(面积-高程积分、地貌信息熵以及河流纵剖面)的研究结果均显示黑河流域所涉及的祁连山东、西段的构造活动存在明显差异,具有西强东弱的特点,如西段流域的平均面积高程积分值(HI)为0.541而东段仅为0.4661;并且根据河流纵剖面分析得到的差异隆升值西段为754m,也远高于东段的219m;而降雨等气候因素则存在东强西弱的特点。综合对比分析发现,本区岩性与降水条件等对研究区地貌因子的影响有限;构造活动是地貌演化发育的主控因素,控制着该区现今的构造变形、地貌发育及其演化历史。     

龙门山中北段流域地貌特征及其构造意义

龙门山中北段位于青藏高原东缘,该区作为高原向东扩展的前缘部位,其地形与河流水系的演化记录了高原隆升与挤压扩展及其气候环境效应的各种信息。龙门山中北段构造活动有明显差异,从中段逆冲为主转化为北段的走滑为主,本文采用定量化地貌参数从构造地貌的角度揭示了区域构造活动的差异。龙门山中北段地貌因子（坡度、地形起伏度和条带状剖面）的阶梯状分布特点,显示了高原扩展的逆冲推覆特征,在中央断裂处构造抬升作用最强,同时显示出了南北向构造活动减弱的趋势,由中段的逆冲转换为北段逆冲兼走滑的形式。北川-映秀断裂两侧流域的HI值也显示了断裂上盘高、下盘低、沿走向减弱的趋势。综合分析认为,本区构造活动是地貌演化的主控因素,龙门山中北段地形存在差异,北川-映秀断裂两侧的小流域地貌指数分析显示,构造抬升活动自南向北减弱,中段以逆冲为主,北段为逆冲兼走滑。     

涪江流域河流地貌特征对虎牙断裂带活动性的响应

青藏高原东缘岷山东边界的虎牙断裂带强震频发,但因第四系保留有限,目前对于该断裂的活动性仍认识不清。而基岩山区河流地貌与活动构造关系研究发现,河流地貌特征能够很好地记录构造活动信息。虎牙断裂带横跨涪江流域,这为通过河流地貌研究虎牙断裂的活动特征提供了条件。文中选择涪江流域SRTM 30m精度数字高程模型(DEM)数据,利用GIS技术提取了涪江流域坡度(slope)、局部起伏度(local relief)、标准化陡峭指数(ksn)、面积-高程积分值(HI)等地貌指数,并对跨虎牙断裂带小流域盆地的平均陡峭指数(ks)和面积-高程积分值进行对比,结合野外调查、岩性、降水与现代侵蚀速率等特征,分析讨论了涪江流域地貌特征与虎牙断裂带活动特征的关系。研究表明:1)涪江流域基本处于稳态状况,区内仅有跨雪山断裂带的河道剖面显示明显的裂点,其余跨断裂河道剖面无明显裂点存在;2)虎牙断裂带两侧地貌指数差异明显,整体上表现为西高东低,这应与虎牙断裂的逆断活动有关;3)断裂两侧的小流域地貌指数差异分析表明,沿虎牙断裂带自北向南抬升作用逐渐增强,反映了虎牙断裂带北段以走滑为主,南段以逆断为主。该研究有助于提高对青藏高原东缘隆升变形机制的理解。     

基于地震活动性资料估计海原断裂倾角

本文以海原断裂带区域活动构造为基础,将海原断裂划分为西、中、东3段.基于1999年12月26日至2010年7月26日间的精定位小震目录,估计了海原断裂带各段的倾角.考虑海原断裂沿走向可能存在南倾与北倾两种情况,将倾角的范围设置为.首先运用网格搜索法确定了平面断层模型,其次以特征深度节点为基础数据运用多项式构建了曲面断层模型.结果表明：当进行平面拟合时,海原断裂西段与中段、东段的倾向不同,西段为南倾,其倾角值为71°,而中段、东段为北倾,其倾角值分别为72°、65°,各段的倾角值均由地表以下8 km地震资料确定.当进行曲面拟合时,在8 km深度以内海原断裂西段、中段、东段的倾角均处于80°左右,即接近陡立.西段的倾角在深度为9 km处出现转换,之后倾角接近陡立;中段的倾角在深度为16 km处出现转换,之后倾角逐渐减小,当深度为18 km时倾角为30°;东段的倾角在深度为11 km处出现转换,倾角为42°,在深度为16 km处出现第二次转换,倾角为55°,之后倾角逐渐减小.结合震源机制解和大地测量观测资料反演拟合的合理性,验证了本文所估计倾角的可靠性.     

海原断裂带分段地震潜势分析

利用近年来在海原断裂带各断裂段取得的最新古地震资料,通过实时概率模型,对海原断裂带东段、中段、西段进行了地震潜势的定量评估。得出海原断裂带东段、中段、西段未来100年内发生7级以上地震的概率分别为3．15％、11．35％、5．15％,未来200年内发生7级以上地震的概率分别为6．05％、22．8％、9．75％。     

祁连山东段石羊河流域河流纵剖面及其构造意义

石羊河流域位于祁连山东段,其河流体系记录了最新的构造信息和构造活动。提取石羊河流域的地貌信息,有助于揭示祁连山东段石羊河流域地貌对构造活动的响应,及系统探讨该区地貌发育特征及其所蕴含的构造意义。文中基于GIS空间分析技术,利用数字高程模型(DEM)、Matlab脚本提取了石羊河流域7条河流的纵剖面,并利用基岩河道水力侵蚀模型对其进行分析,获得了7条河流的陡峭系数、平均侵蚀量、凹曲度、裂点分布、高程、距河流出水口距离和流域面积等地貌信息。结果表明,石羊河流域的各条支流至少存在1个主裂点,裂点上、下河段具有不同的陡峭度(ks)与凹曲度(θ),说明河流纵剖面裂点的上、下河段具有不同的发育趋势。对河流纵剖面、裂点分布及岩性进行综合分析,结果表明,古浪河、金塔河、杂木河、西营河、东大河和西大河都具有"坡折式"裂点,处于瞬时状态。祁连山东段河流地貌演化主要与构造活动相关。利用本区晚第四纪活动断裂相关裂点上游河道的凹曲度指标拟合出整条河流,得到石羊河流域的平均侵蚀量约488m,发源于古浪推覆体的6条支流的平均侵蚀量为508. 5m。进一步计算研究区河网归一化的河流陡峭系数(ksn)并得到其空间分布,结合河流纵剖面和裂点分析结果对祁连山东段石羊河流域的构造特征进行了综合分析,ksn的结果显示下游段陡峭系数<60,中游明显大于下游。同时,位于构造结处的古浪推覆体其ksn值呈现高值,表明该区第四纪以来经历了明显的构造抬升过程。文中结果表明石羊河流域地貌演变处于非均衡状态,构造变形是祁连山东段地貌演化的主要影响因素,控制着该区现今的地貌发育及演化历史。     

畹町断裂带地貌特征及构造意义指示

为定量认识畹町断裂带地貌特征及其对构造的指示意义,基于30 m的DEM数据,采用空间分析方法,提取该断裂带地形剖面、地形起伏度、坡度、水系偏转角、河流纵剖面上凹指数等参数数值,得到了畹町断裂带构造地貌的一些定量化特征,并通过这些数值特征讨论了其指示的构造意义。结果表明,研究区总体地势以畹町断裂为界东北高西南低,海拔沿断层垂直方向随距离的增加而增加到1 500~2 000 m后趋于平稳。垂直断层方向的地形剖面反映的阶地特征与普通意义的侵蚀阶地的特征差异明显,表明畹町断裂在很大程度上控制了区域河流阶地的发育及其形态特征。断裂两侧水系分布明显不对称,沿走滑断裂水系发生系统性拐弯,且水系级别越高,其拐弯距离越长。沿畹町断裂(怒江干流)走向分布的11条水系偏转角的角度大致在45°~175°之间,多数分布在100°范围内,高于100°的有3个。畹町断裂带水系偏转角的数值特征说明水系在断层左旋走滑作用的长期影响下,汇入角发生了偏转。区域内92.31%的河流纵剖面上凹指数b1,纵剖面为凹形,反映了畹町断裂对其发育的影响。     

沿走滑活动断层的基岩河道系统位错——以青藏高原东部为例

河流位错是沿走滑活动断层的重要构造地貌之一。然而,由于河流复杂的自然形态、沿走滑断层容易发生河流袭夺等因素,使得利用河流形态来判断走滑断层的滑动方向、位错量等存在一定的困难。文中系统介绍了利用基岩河道系统位错对沿走滑断层的河流位错地貌进行分析的方法。系统水系位错是构造过程和地表过程沿走滑活动断层相互作用的结果,是穿过走滑活动断层的河流累积位错量的同时在溯源侵蚀作用下向上游方向增长的现象。对青藏高原东部甘孜-玉树、鲜水河、昆仑东段3条走滑断裂带的河流位错地貌进行的解译、测量和统计表明,沿3条断裂带都发育系统水系位错,河流从源头到断层的上游长度(L)越长,其累积的位错量(D)越大,两者之间存在线性相关关系D=a·L。为研究青藏高原东部构造地貌演化过程中走滑断裂带的作用提供了重要依据。     

基于GNSS的青藏高原东北缘地壳运动场及强震趋势研究

利用“中国大陆构造环境监测网络”GNSS数据研究1998—2018年青藏高原东北缘排除同震影响等干扰后的速度场、主应变率场、最大剪切应变率场、面应变场等的变化,活动断裂滑动速率变化、跨活动断裂基线变化等。将研究区域内的二级块体再分区,获得各次级块体内部的应变率变化;获取研究区域地壳运动场的趋势性、动态特征。研究结果显示,阿尔金断裂带中东段、祁连块体和柴达木块体交界、巴颜喀拉块体与羌塘块体交界、祁连块体南边界中段、海原—六盘山断裂带和西秦岭北缘断裂带西段的逆冲运动,祁连块体北边界西段、庄浪河断裂的左旋走滑运动,祁连块体北边界东段、西秦岭北缘断裂带东段的左旋逆走滑运动,都属于造成一定程度地壳变形的持续性局部应变增强活动。阿尔金断裂带东段、东昆仑断裂带中西段、祁连块体北边界、庄浪河断裂北段、海原断裂南段、六盘山断裂北段、西秦岭北缘断裂带东段可能存在闭锁,未来十年可能发生M_S6.0以上地震。     

青藏高原东北缘海原构造带马东山阶区深部电性结构特征及其构造意义

海原—六盘山构造带是青藏高原东北缘地区的一条重要边界,在海原断裂带和六盘山断裂带接触区形成了特殊的马东山挤压阶区,本文对跨过该挤压阶区一条密集测点大地电磁剖面数据进行了处理和二维反演,获得的深部电性结构图像揭示在马东山挤压阶区深部电性结构表现为在高阻背景下镶嵌多个向西南倾斜的低阻条带电阻率结构样式,并在深度约25 km汇聚到中下地壳低阻层内,共同组成"正花状"结构;海原—六盘山构造带西南侧到陇中盆地区间呈现高、低阻相互"楔合"的深部结构特征,而其东北侧的鄂尔多斯西缘带自地表到中下地壳为较完整的高阻块体.另外结合跨过海原断裂带中段和西秦岭造山带的大地电磁探测结果,对海原—六盘山构造带分段性及其两侧的陇中盆地和鄂尔多斯地块的接触关系进行了研究分析.大地电磁探测成果佐证了在海原断裂带中段为具有走滑特点的断裂,而其尾端与六盘山断裂带斜交区域的马东山地区发生了强烈的逆冲推覆与褶皱变形;活动构造研究发现沿海原断裂带所产生的左旋走滑位移被其尾端的马东山、六盘山以东西向的地壳缩短调节吸收,GPS观测表明青藏高原东北缘地区现今构造变形分布在海原—六盘山构造带以西上百公里的范围内,陇中盆地—海原—六盘山构造带和鄂尔多斯地块一线的深部电性结构图像也很好地解释了该区变形状态：海原—六盘山构造带带及西南盘的陇中盆地的中下地壳非常破碎,在青藏高原向北东方向的推挤下容易发生变形,而北东盘鄂尔多斯地块地壳结构完整,很难发生构造变形.对海原—六盘山构造带马东山阶区和龙门山构造带的深部电性结构及变形特征等进行了比较分析,发现该区有与2008年汶川地震相似的深部构造背景,应重视该区强震孕育环境的探测研究.     

Ice cap erosion patterns from bedrock 10Be and 26Al,southeastern Tibetan Plateau

Quantifying glacial erosion contributes to our understanding of landscape evolution and topographic relief production in high altitude and high latitude areas. Combining in situ ¹⁰Be and ²⁶Al analysis of bedrock, boulder, and river sand samples, geomorphological mapping, and field investigations, we examine glacial erosion patterns of former ice caps in the Shaluli Shan of the southeastern Tibetan Plateau. The general landform pattern shows a zonal pattern of landscape modification produced by ice caps of up to 4000 km² during pre-LGM (Last Glacial Maximum) glaciations, while the dating results and landforms on the plateau surface imply that the LGM ice cap further modified the scoured terrain into different zones. Modeled glacial erosion depth of 0–0.38 m per 100 ka bedrock sample located close to the western margin of the LGM ice cap, indicates limited erosion prior to LGM and Late Glacial moraine deposition. A strong erosion zone exists proximal to the LGM ice cap marginal zone, indicated by modeled glacial erosion depth >2.23 m per 100 ka from bedrock samples. Modeled glacial erosion depths of 0–1.77 m per 100 ka from samples collected along the edge of a central upland, confirm the presence of a zone of intermediate erosion in-between the central upland and the strong erosion zone. Significant nuclide inheritance in river sand samples from basins on the scoured plateau surface also indicate restricted glacial erosion during the last glaciation. Our study, for the first time, shows clear evidence for preservation of glacial landforms formed during previous glaciations under non-erosive ice on the Tibetan Plateau. As patterns of glacial erosion intensity are largely driven by the basal thermal regime, our results confirm earlier inferences from geomorphology for a concentric basal thermal pattern for the Haizishan ice cap during the LGM. © 2018 John Wiley & Sons, Ltd.     

Paleotopographic controls on loess deposition in the Loess Plateau of China

The underlying pre‐existing paleotopography directly influences the loess deposition process and shapes the morphology of current loess landforms. An understanding of the controlling effects of the underlying paleotopography on loess deposition is critical to revealing the mechanism of loess‐landform formation. However, these controlling effects exhibit spatial variation as well as uncertainty, depending on a study's data sources, methodologies and particular research scope. In this study, the geological history of a study area in the Loess Plateau of China that is subject to severe soil erosion is investigated using detailed geological information and digital elevation models (DEMs), and an underlying paleotopographic model of the area is constructed. Based on the models of modern terrain and paleotopography, we introduce a watershed hierarchy method to investigate the spatial variation of the loess‐landform inheritance relationship and reveal the loess deposition process over different scales of drainage. The landform inheritance relationships were characterized using a terrain‐relief change index (TRCI) and a bedrock terrain controllability index (BTCI). The results show that the TRCI appears to have an inverse relationship with increasing research scope, indicating that, compared with the paleotopography of the region, modern terrain has lower topographic relief over the entire area, while it has higher topographic relief in the smaller, local areas. The BTCI strengthens with increasing drainage area, which demonstrates a strong controlling effect over the entire study area, but a weak effect in the smaller, local areas because of the effect of paleotopography on modern terrain. The results provide for an understanding of the spatial variation of loess deposition in relation to paleotopography and contribute to the development of a process‐based loess‐landform evolution model. Copyright © 2015 John Wiley & Sons, Ltd.     

丽江-小金河断裂南、中段地貌特征及构造指示意义

丽江-小金河断裂位于青藏高原东南缘,是川滇菱形块体内重要的次级边界断裂。构造活动对区域河流水系的发育有重要影响,因此,定量研究水系地貌特征可在一定程度上反映区域内构造活动信息。本文采用地形坡度、地形起伏度、面积-高程积分值（HI）等地貌参数研究沿该断裂区域地貌对构造活动的响应。研究发现,断裂北侧坡度和地形起伏度较断裂南侧高,跨断裂4级流域盆地内亚流域盆地面积-高程积分值变化也指示断裂北侧流域成熟度低于断裂南侧,这反映了丽江-小金河断裂存在一定逆冲分量。     

Complex erosional response to uplift and rock strength contrasts in transient river systems crossing an active normal fault revealed by 10Be and 26Al cosmogenic nuclide analyses

Understanding the influence of bedrock lithology on the catchment-averaged erosion rates of normal fault-bounded catchments and the effect that different bedrock erodibilties have on the evolution of transient fluvial geomorphology remain major challenges. To investigate this problem, we collected 18 samples for ¹⁰Be and ²⁶Al cosmogenic nuclide analysis to determine catchment-averaged erosion rates along the well-constrained Gediz Fault system in western Türkiye, which is experiencing fault-driven river incision owing to a linkage event ~0.8 Ma and has weak rocks overlying strong rocks in the footwall. Combined with existing cosmogenic data, we show that the background rate of erosion of the pre-incision landscape can be constrained as <92 mMyr⁻¹, and erosion rates within the transient reach vary from 16 to 1330 mMyr⁻¹. Erosion rates weakly scale with unit stream power, steepness index and slip rate on the bounding fault, although erosion rates are an order of magnitude lower than slip rates. However, there are no clear relationships between erosion rate and relief or catchment slope. Bedrock strength is assessed using Schmidt hammer rebound and Selby Rock Mass Strength Assessments; despite a 30-fold difference in erodibility, there is no difference in the erosion rate between strong and weak rocks. We argue that, for the Gediz Graben, the strong lithological contrast affects the ability of the river to erode the bed, resulting in a complex erosional response to uplift along the graben boundary fault. Weak covariant trends between erosion rates and various topographic factors potentially result from incomplete sediment mixing or pre-existing topographic inheritance. These findings indicate that the erosional response to uplift along an active normal fault is a complex response to multiple drivers that vary spatially and temporally.     

APPLICATION OF TOPOGRAPHIC SLOPE AND ELEVATION VARIATION COEFFICIENT IN IDENTIFYING THE MOTUO ACTIVE FAULT ZONE

The eastern Himalaya syntaxis is located at the southeastern end of the Qinghai-Tibet Plateau and is the area where the Eurasian plate collides and converges with the Indian plate. The Namjabawa is the highest peak in the eastern section of the Himalayas, and the Yarlung Zangbo River gorge is around the Namjabawa Peak. The NE-striking Aniqiao Fault with right-lateral strike-slip is the eastern boundary fault of the Namjabawa syntaxis. Motuo Fault is in the east of and parallel to the Aniqiao Fault, distributing along the valley of the Yarlung Zangbo River. The section of Yarlung Zangbo River valley at the eastern side of the Namjabawa area is located in the southern foothills of the Himalayas and belongs to the subtropical humid climate zone with dense tropical rainforest vegetation. Dense vegetation, large terrain elevation difference, strong endogenetic and exogenic forces, and abundant valley deposition bring enormous difficulty to the research on active faults in this area. Since 1990s, surface morphology can be quantitatively expressed by digital elevation models as the rapid development of remote sensing technology. Geomorphic types and their characteristics can be quantified by geomorphological parameters which are extracted from DEM data, describing geomorphologic evolution and tectonic activity. But to date, researches based on quantitative geomorphic parameters are mainly focus on the differential uplift of regional blocks. In the study and mapping of active faults, surface traces of active faults are acquired by visual interpretation of remote sensing images. It has not been reported to identify the location of active faults via the change of quantitative geomorphic parameters. The distribution map of topographic elevation variation coefficient is suitable to reflect the regional erosion cutting and topographic relief, and the places with higher topographic elevation variation coefficient are more strongly eroded. In this paper, we attempt to identify the active faults and explore their distribution in the Yarlung Zangbo Gorge in the east of the Namjabawa Peak based on the application of two quantitative geomorphic parameters, namely, the topographic slope and the elevation variation coefficient. Using the DEM data of 30m resolution, two quantitative geomorphic parameters of topographic slope and elevation variation coefficient in Namjabawa and its surrounding areas were obtained on the ArcGIS software platform. On the topographic slope distribution map, the slope of the eastern and western banks of the Yarlung Zangbo River near Motuo is steep with a slope angle of more than 30°. Under the background of steep terrain, there are gentle slope belts of 5°~25° distributing intermittently and NE-striking. On the distribution map of topographic elevation variation coefficient, the elevation variation coefficient of the Yarlung Zangbo River near Motuo is greater than 0.9. On the background of the high topographic fluctuation area, it develops gently topographic undulating belts with elevation variation coefficient of 0.2~0.9. The belts are intermittently distributed and northeastern trending. Through the field geological and geomorphological investigation and trench excavation, it is found that the abnormal strips of the above-mentioned geomorphological parameters are the locations where the active faults pass. The above results show that the quantitative analysis of the topographic slope and the coefficient of variation of elevation can help us find active faults in areas with large terrain slope, serious vegetation coverage and high denudation intensity.     

滇中汤郎-易门断裂构造活动的地貌特征

汤郎-易门断裂位于青藏高原东南缘,走向近南北,按地貌特征及区域构造背景可将其划分为北段（营盘村-插甸断裂）、中段（插甸-碧城断裂）及南段（碧城-易门断裂）。针对汤郎-易门断裂构造地貌差异,利用30 m分辨率的DEM数据,基于GIS技术提取与断裂活动相关的水系,并计算其陡峭指数,结合野外考察及遥感影像讨论断裂在不同分段的活动习性与地貌特征。研究发现,区域内降水及基岩抗风化能力对亚流域陡峭指数的影响较小,认为陡峭指数能够较好地反映汤郎-易门断裂的垂直构造运动。陡峭指数显示,断裂走向呈两端高、中间低的特点,其分段性与前人划分结果具有较好一致性,所表征的基岩垂直活动性差异可作为断裂带活动分段的依据。断裂带东西侧陡峭指数在不同分段上表现出差异性,北段断裂东西侧陡峭指数显示出东、西向差异性抬升不显著,其与地貌上断裂北段表现的左旋走滑运动一致,以水平运动为主;断裂中段及南段陡峭指数在东西侧表现出东高西低的特点,显示东侧较西侧基岩抬升更快,可能以垂直差异运动为主。     

SLIP OFFSET ALONG STRIKE-SLIP FAULT DETERMINED FROM STREAM TERRACES FORMATION

Slip rate is one of the most important parameters in quantitative research of active faults. It is an average rate of fault dislocation during a particular period, which can reflect the strain energy accumulation rate of a fault. Thus it is often directly used in the evaluation of seismic hazard. Tectonic activities significantly influence regional geomorphic characteristics. Therefore, river evolution characteristics can be used to study tectonic activities characteristics, which is a relatively reliable method to determine slip rate of fault. Based on the study of the river geomorphology evolution process model and considering the influence of topographic and geomorphic factors, this paper established the river terrace dislocation model and put forward that the accurate measurement of the displacement caused by the fault should focus on the erosion of the terrace caused by river migration under the influence of topography. Through the analysis of the different cases in detail, it was found that the evolution of rivers is often affected by the topography, and rivers tend to migrate to the lower side of the terrain and erode the terraces on this side. However, terraces on the higher side of the terrain can usually be preserved, and the displacement caused by faulting can be accumulated relatively completely. Though it is reliable to calculate the slip rate of faults through the terrace dislocation on this side, a detailed analysis should be carried out in the field in order to select the appropriate terraces to measure the displacement under the comprehensive effects of topography, landform and other factors, if the terraces on both sides of the river are preserved. In order to obtain the results more objectively, we used Monte Carlo method to estimate the fault displacement and displacement error range. We used the linear equation to fit the position of terrace scarps and faults, and then calculate the terrace displacement. After 100, 000 times of simulation, the fault displacement and its error range could be obtained with 95%confidence interval. We selected the Gaoyan River in the eastern Altyn Tagh Fault as the research object, and used the unmanned air vehicle aerial photography technology to obtain the high-resolution DEM of this area. Based on the terrace evolution model proposed in this paper, we analyzed the terrace evolution with the detailed interpretation of the topography and landform of the DEM, and inferred that the right bank of the river was higher than the left bank, which led to the continuous erosion of the river to the left bank, while the terraces on the right bank were preserved. In addition, four stages of fault displacements and their error ranges were obtained by Monte Carlo method. By integrating the dating results of previous researches in this area, we got the fault slip rate of(1.80±0.51)mm/a. After comparing this result with the slip rates of each section of Altyn Tagh Fault studied by predecessors, it was found that the slip rate obtained in this paper is in line with the variation trend of the slip rate summarized by predecessors, namely, the slip rate gradually decreases from west to east, from 10~12mm/a in the middle section to about 2mm/a at the end.     

Thermal structure about southwest sub-basin of South China Sea

There are some factors, such as the topographic relief, sedimentary thickness and thermal conductivity, magmatic activity and thermal cooling, influencing the seafloor heat flow and the evolution of lithosphere structure in southwest sub-basin (SWSB), South China Sea. On the base of the geological structure characteristic of SWSB this paper will discuss some other factors including thermal anomaly area, dike produced by magma intrusion and lithosphere relief, by modeling and calculating. Calculating results indicate partial areas where temperature is higher than vicinity in the lithosphere, which we call thermal anomaly here containing thermal anomaly area and dike in this paper, could decrease heat flow below, increase above, and gradually increase to two sides; heat flow in upwelling parts of lithosphere is usually higher than sinking parts, and in the middle is of a gradual transition.     

Twenty-one years of German geomorphology

In recent decades, German geomorphology has been mainly concerned with climatic and climato-genetic geomorphology. The first is the study of processes, especially of process combinations in different climato-morphological zones. The second is concerned with the way exogenic forces control the evolution of relief in a certain region. This study of relief generations differs fundamentally from denudation chronology. Certain principles developed as knowledge of these fields has grown, such as the variability of rock resistance with climate and discontinuity of processes in both space and time, are considered. In recent years new trends, based mainly on climatic geomorphology, have been towards greater specialization in fields such as quantitative geomorphology, geomorphological mapping, and laboratory analysis of regolith and soil samples.