Relationships between tectonic and geomorphological linear features in the Guadix-Baza basin,southern Spain

Linear elements of the landscape of the Guadix-Baza basin, southern Spain, were identified from a Landsat TM image. Three important lineament trends have been identified in the Guadix-Baza basin. The first is NE–SW, which is the dominant trend in the basin; the second is NW–SE, and the third is ENE–WSW. These three trends are correlated to the major faults of the Guadix-Baza basin. The study of linear features by the analysis of satellite data has revealed a strong link between the buried tectonic structures and the morphological features appearing at the surface. The distribution and density of lineaments explains much of the morphology of the land surface. It is possible to reconstruct elements of the tectonic and denudational history of the region and show that during Quaternary times lineaments controlled the sedimentation of the basin and the drainage pattern. Copyright © 1999 John Wiley & Sons, Ltd.     

青海湖流域近六百年来的气候变化与湖水位下降原因

根据青海湖流域及其邻近地区树木年轮资料重建的历史时期气候资料序列,给出了流域近六百年来的主要冷、暖、干、湿期,并对器测时期的气候变化趋势作了分析。指出,近百年来气候暖干化是造成湖水位下降的主要原因;对于湖水位年际变化与前期降水影响系统、不同气候类型以及地面气象要素的关系作了统计分析。     

Transverse canyon incision and sedimentary basin excavation driven by drainage integration,Aravaipa Creek,AZ, USA

Drainage reorganization events have the potential to drive incision and erosion at high rates normally attributed to tectonic or climatic forcing. It can be difficult, however, to isolate the signal of transient events driven by drainage integration from longer term tectonic or climatic forcing. We exploit an ideal field setting in Aravaipa Creek Basin of southeastern Arizona, USA, to isolate just such a signal. Aravaipa Creek Basin underwent a period of transient incision that formed Aravaipa Canyon, evacuating a significant volume of sedimentary basin fill and Tertiary bedrock from the previously internally drained basin. We use digital terrain analyses to reconstruct the pre-incision landscapes of both Aravaipa Creek Basin and the adjacent Lower San Pedro Basin, which we use to quantify the magnitude of incision and erosion since the drainage basins integrated. Terrestrial cosmogenic nuclide burial dates from ¹⁰Be and ²⁶Al concentrations in latest stage basin fill in Aravaipa Creek enable us to calculate long-term incision and erosion rates from 3 Myr to the present. A ¹⁰Be concentration–depth profile from the Lower San Pedro Basin confirms that the San Pedro River incised into its high stand deposits prior to 350 000–400 000 years ago. Combining our landscape reconstructions with these age constraints, we determine that the transient rates of incision that created Aravaipa Canyon were 150 m/Myr or more, but that the background rate of erosion since integration is an order of magnitude lower, between 10 and 20 m/Myr. These results support our growing understanding that tectonic and climatic forcings need not apply for all episodes of rapid, transient incision and erosion during landscape evolution. © 2018 John Wiley & Sons, Ltd.     

A cross-scale comparison of drainage basin characteristics derived from digital elevation models

The feasibility of using small-scale digital elevation models (DEMs) to extract various drainage basin characteristics was evaluated by comparing basin parameters derived from the 1:250 000 DEMs with those from the 1:24 000 DEMs. Twenty basins ranging approximately from 150 km² to 1000 km² in West Virginia, a geologically complex region, were examined in this study. The basin parameters examined included those commonly used in hydrology and geomorphology such as elevation, slope, stream length, drainage density, relief ratio and ruggedness number. Our results suggested that the 1:250 000 DEMs can provide accurate estimates for elevation-based and stream-length-based basin parameters, but not for slope-based parameters. After examining the differences between the DEM-derived basin parameters from the two different scales, we found that the performance of the 1:250 000 DEMs was not significantly influenced by basin size, while terrain complexity seems to be an important factor of accuracy of the estimated basin parameters. Copyright © 1999 John Wiley & Sons, Ltd.     

Sediment budget of the Napo River,Amazon basin,Ecuador and Peru

The upstream‐downstream sediment budget along the Napo River (100 520 km², 6300 m³ s^?1) was studied in the Andean foothills of Ecuador, at the west of the Amazon basin. A comparative study was made during four hydrological cycles (2001–2005) for three hydrological stations located upstream, and during one hydrological cycle (2004–2005) for the fourth one located near the mouth of the Napo River (region of Iquitos in Peru). This analysis showed an unusual increase in the concentration of suspended sediment recorded for the western part of the Amazon plain. Like the runoff (81 l s^?1 km²), which is a world's maximum, the erosion rate (1160 t km^?2 year^?1, i.e. 47% of total suspended solid (TSS) export at the exit of Ecuador), one of the highest for a floodplain basin is the result of a stepper slope than in the rest of the Andean foothills, where typically sedimentation phenomena are predominant, and can be explained in part by a greater tectonic activity. Similar phenomenes were evidenced in small mountainous rivers in New Guinea (Milliman and Syvitski, 1992; Milliman, 1995). On the headwaters of the Napo River drainage basin, the tectonic uplift causes the Pastaza Megafan's existence. This progressively diverts the course of Napo River towards north and also provokes the remobilization of fine fluvial deposits. Moreover, this geodynamic trend is completed by the impact of volcanic eruption, earthquakes and landslides. The combination of these phenomena, so common in the region, has provided a large sediment transfer, not only at present but also in the past, as can be confirmed by the presence of incised terraces, mainly formed by volcanic materials. Then, these results were compared with a similar study carried out further south in the Madeira basin at the Bolivian foothills. These studies show the spatio‐temporal variability of the relation between sediment transfer and geodynamic processes at the Andean Piedmont. Copyright © 2009 John Wiley & Sons, Ltd.     

变化环境下珠江流域洪水频率变化特征、成因及影响(1951-2010年)

气候变化和人类活动导致珠江流域水文变化,变化前后洪水频率分布显著不同.运用滑动秩和(Mann-Whitney U test)结合Brown-Forsythe、滑动T、有序聚类和Mann-Kendall检验法,并用累积距平曲线法获取年最大流量序列详细信息,综合确定样本最佳变化节点,并对水文变化成因做了系统分析.在此基础上,对整体序列、变化前后序列用线性矩法推求广义极值分布参数以及不同重现期设计流量.结果表明:(1)西江大部以及北江流域最佳变化节点在1991年左右;东江流域最佳变化节点与该流域内3大控制性水库建成时间基本吻合;(2)变化后,西江、北江年最大流量持续增加,洪峰强度增大,尤其是西江干流年最大流量显著增加;东江流域年最大流量显著减小,洪峰强度降低;(3)变化后,西江与北江洪水风险增加,尤其是下游珠三角地区本身受人类活动显著影响,加之西江与北江持续增加的洪水强度,珠三角地区发生洪水的强度及频次加剧,而东江洪水风险减小.此研究对于珠江流域在变化环境下的洪水风险评估与防洪抗灾具有重要意义.     

Poly-phase salt tectonics and hydrocarbon accumulation in Tarim superimposed basin, northwest China

The purpose of this paper is to discuss the poly-phase salt tectonics and its relation to the hydrocarbon accumulation of the Tarim superimposed basin. Several salt sequences are developed in the Tarim basin, they are: (1) the Mid-Early Cambrian salt sequence, mainly distributed in the west part of the north Tarim uplift and Keping uplift; (2) the Early Carboniferous salt sequence, mainly distributed in the south slope of the north Tarim uplift; (3) the Paleogene salt sequence, mainly distributed in the mid-west part of the Kuqa foreland fold belt and north Tarim uplift; and (4) the Miocene salt sequence, mainly distributed in the east part of the Kuqa foreland fold belt. The salt sequences deposited in the tectonically calm scenario, while the salt layers deformed during the period of intense tectonism. Although the salt sequences are characteristic of plastic flow, the differences of salt deformation styles exist in the different salt sequences because of the different deformation mechanism. It is attractive that the distribution of the large oil-gas fields or pools has a bearing upon the salt sequences and salt structures, such as the Tahe oilfield related to the Lower Carboniferous salt sequence and laterally facies changed mudstone, the Kela No.2 gas field to the Paleogene salt structures, and the Dina gas field to the Miocene salt structures. It is indicated that the large-scale hydrocarbon accumulation is controlled by the poly-phase salt sequences and structures. The deep analysis of the poly-phase salt tectonics is helpful to understanding the characteristics of the structural deformation and oil-gas accumulation of the Tarim basin.     

Rifting and basin inversion in the eastern margin of the Japan Sea

Abstract Extensional basin formation and subsequent basin inversion in the southern area of the eastern margin of the Japan Sea were studied on the basis of the interpretation of seismic profiles (total length approximately 15 000 km) and the fossil analyses of 77 sea-bottom samples. Rift (Early to Early Middle Miocene), post-rift (Middle to Late Miocene), pre-inversion (Late Miocene to Pliocene) and inversion stages (Pliocene to Quaternary) were differentiated by the extension and contraction of the crust. Many small-scale rifts were formed in the Sado Ridge and the Mogami Trough during the rift stage, simultaneous with back-are spreading of the Japan Sea. Most of the rifts were east- or southeast-facing, rotational half-grabens bounded by west-dipping normal faults at their eastern boundaries. The syn-rift sequence can be divided into lower and upper units by an erosional surface. The sequences are presumed to be composed mainly of fining-upward sediments. The trend of most rifts is north-northeast with the remainder being of east-northeast-bias. The north-northeast trending rifts are distributed widely in the Sado Ridge and Mogami Trough and do not show an en échelon arrangement, suggesting that they were formed mainly by pure extension nearly perpendicular to the arc. The east-northeast trending rifts are presumed to have been developed by a north-northwest extension in the late rift stage, which may have accompanied a right-lateral movement in the eastern margin of the Japan Sea. During the post-rift stage, the rifts and adjacent horsts subsided and became covered by the post-rift sequence, characterized by parallel and continuous reflections. This suggested no significant tectonic movements in this period. In the pre-inversion stage many of the rifts subsided again, presumably because of down-warping due to weak compressional stress. The normal faults reactivated as reverse faults during the inversion stage due to an increase in compressional stress. Many of the rifts have been uplifted and transformed into east-vergent asymmetric anticlines. The basin inversion is greatest in the Sado Ridges and in the Dewa Bank Chain, while it is least developed in the Mogami Trough and in the western slope of the Sado Ridge, in which some normal faults have not been reactivated. The increase and decrease of the inversion corresponds to the peak and trough of undulation at an interval of about 50 km trending parallel to the arc.     

长江流域水库"过滤器效应"对入海溶解硅通量的影响

根据1960-2000年间长江大通水文站记录的水、沙以及硅、氮、磷等数据,结合1954-2006年间长江流域库容大于10⁸ m³的162座水库的库容、上游径流量、总磷等数据,利用Vollenweider模型分析了水库"过滤器效应"对入海溶解硅(DSi)通量的影响.结果表明:1)1990s相比1960s,长江入海DSi通量下降了约1.85×10⁶ t/a,减少了大约25.3%;入海DSi通量的下降与流域径流波动、入海悬沙通量下降以及溶解无机氮通量的增加紧密相关.2)流域水库明显改变径流的自然过程,增加径流的滞留时间,流域90%以上的水库对上游径流的滞留时间超过0.05年,水库产生显著的DSi"生物过滤器"效应.模型计算显示流域大型水库对DSi的累计滞留量可达0.85×10⁶ t/a,占年均入海DSi通量(1990-2000年)5.4×10⁶ t的15.7%,是入海DSi通量减少量(1.85×10⁶ t/a)的45.9%.3)根据保守估计,流域162座大型水库内泥沙累计淤积量达6.75×10⁸ t/a,不仅使悬沙入海通量显著下降,而且造成大量颗粒吸附的外源和内源DSi颗粒沉淀,这对入海DSi通量减少也起到重要贡献.但目前对水库"泥沙过滤器"的滞留机理并不清楚,需要展开进一步的研究.     

Interpretation of the microtremor spectra at the Zafarraya basin, southern Spain

The microtremor spectra observed at the sediment-filled basin of Zafarraya show a peak near 2·8 Hz, independent of the local basin depth. Based on geoelectric and geologic data we constructed a tentative model of the site. The seismic response for vertically incident plane waves, both SH and P-SV, was computed by the finite-difference method. The observed spectral peak was found to be due to a combined effect of the 2-D basin bottom shape and the horizontally layered basin fill. Neither of the two effects explain the spectra when treated separately. Synthetic seismo-grams indicate a transitional basin behaviour, little investigated so far, between that typical of local basin-induced surface waves and a global 2-D resonance. A practical conclusion is that the site effects cannot be simply assessed by means of the basin shape ratio (thickness to half-width ratio) and the velocity contrast at the bottom.     

应用MODIS数据监测千岛湖流域植被覆盖动态(2001-2013年)

流域植被覆盖状况对于水源地生态环境保护具有重要的指示作用.当前的水质目标管理不仅要着眼于湖库水质参数控制,更应该从整个流域的角度维系生态平衡.在此背景下,依托长时间序列MODIS遥感数据对千岛湖流域2001-2013年植被覆盖状况进行监测,采用最小二乘法趋势分析和Mann-Kendall显著性检验方法分析了千岛湖流域植被的空间分布特征、时间变化特征与长期变化趋势.研究表明该方法能够有效地监测流域植被覆盖的时空动态变化:1)从空间分布上来看,千岛湖流域植被覆盖状况整体较好,但同时也发现受人为干扰较大的地域如河、湖附近的城镇建设用地、农业用地以及园地,其NDVI值明显低于自然林地;2)从时间变化特征上看,2001-2013年千岛湖流域植被年际NDVI在0.69~0.73之间波动,且近年来有增长趋势,年内季节性NDVI动态分析表明高时间分辨率的MODIS数据能够用来区分常绿植被与落叶植被的物候特征,以分析不同植被类型对流域氮、磷流失的风险差异;3)从变化趋势上看,2001-2013年植被覆盖状况改善的区域远大于退化的区域,其中改善区域约占流域面积的55.90%,呈现出一定退化状态的区域约占29.60%(严重退化区域仅占3.97%),而相对稳定不变区域约占14.51%.经与气温与降水等气候因子进行相关性分析表明,植被NDVI与气温呈显著正相关,而降水则不敏感,说明气温是研究区植被生长的主导气候因子.同时发现,人类活动对局部植被变化影响较大.研究结果可为流域水资源与生态环境保护提供空间数据支撑.     

Sediment transferring function of the lower reaches of the Yellow River influenced by drainage basin factors and human activities

Since 1986, with a sharp decrease in water dis-charges, the Yellow River has entered a period charac-terized by low discharges and seasonally occurring dry-ups[1,2]. Since 1999, more strict management of water diversion has been imposed, and therefore the dry-ups have been well under control. However, the lower reaches of the Yellow River is still predominated by low-discharges, and has become a man-induced shrinking river. In the past 40 years, significant effect of soil and water conservat…     

Tilting of active folds and drainage asymmetry on the Manawatu anticlines,New Zealand: a preliminary investigation

The apparent southward tilting of five anticlines in the Manawatu, North Island, New Zealand, is investigated using two drainage basin analysis techniques: the transverse topographic symmetry factor (T) and the asymmetry factor (AF). The techniques are used to determine whether westward‐flowing trunk streams on the gentle western limbs of five anticlines are migrating southwards across their drainage basins, concomitant with down‐tilting of the fold axes. While results show potential for the techniques to be applied in such a tectonic setting, our findings are inconclusive. This could be due to the incipient nature of the folds (c. 0·5 Ma in age), and it would seem more appropriate to apply the techniques in concert with detailed field analyses of river migration patterns. Copyright © 2008 John Wiley & Sons, Ltd.     

Wave tectono-sedimentary processes in Tarim basin

Wave analysis of basins is not only important to the crustal undation theory but also significant to petro-leum exploration by providing information such as the unconformity formation, migration and interchanges between uplifts and depressions, the migrations of sedimentary facies, and basin evolutionary stages. Early in the last century, Haarmann (1930, cited in Jacobs[1] and Scheidegger[2]) and Bemmelen (1933, cited in Jacobs[1] and Scheidegger[2]) put forward the theory of crustal undatio…     

浅析太原台记录太原盆地地震波形的特征

选用太原台DD—1仪记录到的太原盆地多种波形并将其整理归纳，总结出了横穿和纵穿盆地到达记录台站的两种波形特点，并分析了它们呈现该特征主要是源于波在传播过程中地壳厚度分布不均、震源机制以及各种波本身的物理性质不同而造成的。     

Geomorphic characteristics of the Minjiang drainage basin (eastern Tibetan Plateau) and its tectonic implications: New insights from a digital elevation model study

Abstract   The Minshan Mountain and adjacent region are the major continental escarpments along the eastern Tibetan Plateau. The Minjiang drainage basin is located within the plateau margin adjacent to the Sichuan Basin. Based on the analysis of the digital elevation model (DEM) acquired by the Shuttle Radar Topography Mission (SRTM), we know that the Minjiang drainage basin has distinct geomorphic characteristics. The regular increasing of local topographic relief from north to south is a result of the Quaternary sediment deposition within the plateau and the holistic uplift of the eastern margin of the Tibetan Plateau versus the Sichuan Basin. Results from DEM-determined Minjiang drainage sub-basins and channel profiles show that the tributaries on the opposite sides are asymmetric. Lower perimeter and area of drainage sub-basins, total channel length and bifurcation ratio within eastern flank along the Minjiang mainstream are the result of the Quaternary differential uplift of the Minshan Mountain region. Shorter stream lengths and lower bifurcation ratio might be the indications of the undergrowth and newborn features of these eastern streams, which are also representative for the eastern uplift of the Minshan Mountain.     

Unraveling the roles of asymmetric uplift,normal faulting and groundwater flow to drainage rearrangement in an emerging karstic landscape

Landscape adjustment to tectonic, lithologic and climatic forcing leads to drainage reorganization and migration of divides. The respective contribution of these forcings, especially on carbonate landscapes is not well defined. Here, we have addressed this issue by combining field observations, satellite image interpretation and digital elevation model (DEM) quantitative analysis to assess drainage response to spatially heterogeneous rainfall, asymmetric uplift, and normal faulting on an emerging carbonated platform (Sumba Island, Indonesia). We map geomorphic markers of fluvial dynamics and drainage rearrangement and compute a χ parameter that incorporates the contributions of unevenly distributed precipitation and asymmetric uplift to estimate erosional disequilibrium across drainage divides. We find that asymmetric emergence of Sumba Island created an initial parallel drainage, asymmetric across a divide that propagates landwards. Soon after establishing itself on the emerging slopes this drainage was disturbed by normal faulting, which has become the main force driving drainage rearrangement. Vertical offsets across normal fault scarps first triggered aggradation within valleys over the hanging walls, and then disconnected upstream reaches from downstream reaches, leading to the formation of wind gaps atop the fault scarps and upstream perched sedimentary basins. The defeat of rivers by growing fault scarps was catalysed by the possibility for surface water to be rerouted near the fault scarps into underground water networks inside the underlying carbonates. At the end of the process, the opposite drainage across the main water divide captured the struggling drainage. Capture mechanisms include initial groundwater capture of the perched alluvial aquifers, followed by ground sapping at the head of the opposite drainage and surface stream diversion by avulsion. Finally, normal faulting is the main driving force of drainage rearrangement allowing avulsion and karstic rerouting whereas asymmetric uplift and climate forcings have shown a low efficiency. The role of karstification is more ambiguous, catalysing or inhibiting drainage rearrangement. Copyright © 2018 John Wiley & Sons, Ltd.     

巢湖典型子流域上下游水塘对暴雨径流氮磷去除效率比较

从流域上下游环境条件及氮磷输出强度差异出发,探讨上下游水塘对径流氮磷去除的特征及效率,选取巢湖小柘皋河源头流域上下游水塘开展水塘去除暴雨径流氮磷的对比试验,研究暴雨及暴雨间期上下游水塘氮磷去除效率差异及原因,为流域上下游设计不同类型净化塘去除氮磷提供科学依据.结果表明:暴雨期,上游径流氮磷浓度高于下游,且颗粒态所占比例上游大于下游,流域上游应作为防治暴雨径流氮磷流失的重点区域;暴雨期,上游塘对暴雨径流中的氮磷去除效果明显,氮、磷去除率分别为74％和52％,且对颗粒态去除效果好于溶解态,下游塘没有表现出明显的去除效果;暴雨间期,上游塘塘内氮磷浓度平均下降50％和20％,下游塘则分别为72％和16％,且均以溶解态去除为主;水塘去除暴雨径流氮磷有一定的浓度适用范围,浓度过低,去除效果不明显;流域部位不同引起入塘径流氮磷浓度和形态的差异是上下游水塘对暴雨径流去除效果差异的主要外部原因.流域上游出山口,可以在渗透性好的山前洪积扇上构建深水宽塘,通过增加暴雨径流拦截量和降低流速增强物理沉降作用,实现暴雨径流氮磷的高效去除;流域下游农田区,宜构建水面较大的浅滩湿地,通过延长滞留时间和促进生物活动增强去除暴雨径流氮磷的效果.     

First-order drainage basin morphology—definition and distribution

First-order drainage basin morphology consists of two complementary regions: a headwater region, the valley head; and a stream region, the channelway (Figure 1). Each subbasin's morphology is represented by a set of principal components factors that include the properties of area, length, slope, relief, elongation, and plan curvature. The channelway region is a highly-integrated morphological unit that is dominated by a size-shape factor, indicative of an organized flow system and the presence of a permanent channel. The valley head region shows little integration of its morphological factor set, and this is reflected by its lack of a permanent channel. The valley head-channelway definition is utilized to classify first-order basins into three morphological groups or types. Basin type is related to basin location within the larger drainage network, and this relation helps to explain variations in subbasin morphology. The channelway's morphologic properties are influenced by the location of the first-order basin's bifurcation or junction within the higher-ordered network; and valley head morphology is related to the location of the basin's divide position within the drainage net.