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1.
Flow and sediment dynamics in a low sinuosity, braided river: Calamus River, Nebraska Sandhills 总被引：1，自引：0，他引：1
The interaction between channel geometry, flow, sediment transport and deposition associated with a midstream island was studied in a braided to meandering reach of the Calamus River, Nebraska Sandhills. Hydraulic and sediment transport measurements were made over a large discharge range using equipment operated from catwalk bridges. The relatively low sinuosity channel on the right-hand side of the island carries over 70% of the water discharge at high flow stages and 50–60% at low flow stages. As a result, mean velocity, depth, bed shear stress and sediment transport rate tend to be greater here than in the more strongly curved left-hand channel. The loci of maximum flow velocity, depth and bed shear stress are near the centre of the channel upstream of the island, but then split and move towards the outer banks of both channels downstream. Variations in these loci depend on the flow stage. Topographically induced across-stream flows are generally stronger than the weak, curvature-induced secondary circulations. Water surface topography is controlled mainly by centrifugal accelerations and local changes in downstream flow velocity. The averaged water surface slope of the study reach varies very little with discharge, having values between 0·00075 and 0·00090. As bed shear stress generally varies in a similar way to mean velocity, friction coefficients vary little, normally being in the range 0·07–0·13. These values are similar to those in straight channels with sandy dune-covered beds. Bedload is moved mainly as dunes at all flow stages. Grain size is mainly medium sand with coarse sand moved in thalwegs adjacent to the cut banks, and with fine sand at the downstream end of the island. These patterns of flow velocity, depth, water surface topography, bed shear stress, bedload transport rate and mean grain size can be accurately predicted using theoretical models of flow, bed topography and sediment transport rate in single river bends, applied separately to the left and right channels. During high flow stages deposition occurs persistently near the downstream end of the island, and cut banks are eroded. Otherwise, erosion and deposition occurs only locally within the channel as discharge varies. Abandonment and filling of a strongly curved channel segment may occur by migration of an upstream bar into the channel entrance at a high flow stage. 相似文献
2.
An analysis of the planform changes of the Colombian reach of the Amazon River was carried out over a period of 19.9 years. Remote sensing image processing techniques were applied to Landsat images acquired in 1986, 1994, 2001 and, 2006. These images were selected based on minimal daily water level variations, while providing the widest temporal span. Plan view river changes and geomorphologic characteristics were examined to identify which channel pattern classification best represents this large tropical river system. Discharge was also analyzed to determine whether changes in the river's plan view are a direct response to variations in discharge. The system had a depositional tendency between 1986 and 2006, with a period where erosion was more intense than deposition between 1994 and 2001. Percent change in the plan view area of the system (1.4% yr−1) and the maximum migration rates (125 m yr−1) suggest that this reach of the Amazon is less active than reaches upstream and the downstream reach between the confluences of the Jutaí and Japurá Rivers. Variations in discharge appear to be responsible for deposition and erosion dynamics observed after this remote sensing analysis in the Colombian reach of the Amazon River. Characteristics including multiple channels with vegetated islands developed from within-channel deposition, meandering planform, lateral activity of channel margins, and the absence of islands with saucer-like morphology suggest a multichannel, meandering pattern for this reach of the Amazon, that corresponds to a laterally active anabranching river. 相似文献
3.
沙洲是塑造分汊型河道最重要的形态因子,其发育与蚀退由于上游来水来沙变化呈现冲淤交替,从而影响分汊河道输水输沙平衡.通过单个卵石沙洲的淤积和冲刷试验,揭示不同加沙速率、粒径和来流量条件下,沙洲淤积和冲刷规律,并建立简化理论模型分析沙洲淤积速率.结果表明,4组加沙试验中,分流点后出现明显淤积下延至洲头,左汊和右汊成为输沙通道,洲尾中心线两侧的左右汊道有泥沙淤积,洲尾未出现淤积.7组清水冲刷试验中,洲头最先承受冲刷和蚀退,并沿洲体冲刷延伸,洲头冲刷的泥沙沿左右汊水流带到下游,洲尾未出现明显冲刷.卵石沙洲以洲头淤积为主导发育模式,泥沙粒径、洲头坡角和分流角是决定淤积速率的关键因子. 相似文献
4.
Experimental modelling of an aggrading braided river has allowed investigation of the relationship between the frequency of channel avulsion ( A f ), the duration of time that the braidplain is occupied by flow, the spatial pattern of braidplain sedimentation and how these respond to a change in sediment supply ( S s ). Model results demonstrate a strong, positive relationship between S s and A f and that there is no downstream change in A f over the short braidplain distances ( ca 100 m) modelled herein. Although A f is strongly dependent on S s , the degree of channel switching does not influence the rate, or spatial pattern, of braidplain sedimentation. All experiments used a single, central input for water and sediment, and the channels occupied the centre of the alluvial basin for a longer period of time than the margins for all sediment supply rates and distances downstream. Despite this spatio-temporal pattern in flow occupancy, braidplain sedimentation rates were nearly uniform both downstream and across the basin, and increased at approximately the same rate as increases in S s . As a consequence, less frequent, and possibly short-lived, flows at the margins of the braidplain deposited and preserved more sediment per unit time in comparison with the centre of the basin where flow occupancy was higher. An approximate order of magnitude change in sediment supply resulted in only a factor of two change in bed slope, probably due to both an increase in channelization and adjustment of the channel form that maintained sediment transport through the basin. This result suggests that linear diffusion models are unlikely to be applicable in landscape evolution models that possess aggrading multi-thread rivers, which are capable of self-adjustment in channel number and form. 相似文献
5.
Heterogeneous coarse grained channels are often characterized by local transitions in bed surface roughness. Distinct spatial zones in terms of grain size have been reported, for example sand ribbons and bedload sheets. The transition from areas of finer to coarser grained surface sediment is often abrupt. However, the effects of these transitions on the shape of the velocity profile and associated shear velocity and roughness length estimates have not been investigated in detail in coarse grained channels. This paper therefore examines the combined effects of a sudden change in surface roughness and of superimposed scales of resistancé on the structure of the turbulent boundary layer. Measurements along roughness transitions from smooth to rough beds were conducted in a flume using artificial roughness features and in a natural gravel bed river. Immediately at the transition from a zone of close packed roughness to a rougher section dominated by obstacles superimposed on the more or less uniform roughness surface, boundary shear stress and roughness length increase considerably. Downstream from this transition, velocity profiles become concave upwards. Downstream and upstream sections show significant differences in terms of near bed velocities (deceleration downstream of the transition), velocity gradient and turbulence intensity of the streamwise velocity component. Comparing the mean velocity profiles corresponding to these two different roughness surfaces gives some indication of the proportion of total shear velocity (or shear stress) associated with the pressure drag produced by large and isolated obstacles. 相似文献
6.
Accurately identifying and quantitatively describing abandoned channels in meandering rivers are of great significance for improving hydrocarbon recovery. By using modern deposition analogy, field outcrop analysis, a dense well spacing, core observations and a review of the literature, this paper studied the formation process and space–time amalgamation of abandoned channels in meandering river. The results reveal that formation mechanisms of abandoned channels include chute cutoff patterns(shoal-cutting, ditch-scouring and embayment-eroding patterns) and neck cutoff patterns. The chute cutoff pattern forms a gradually abandoned channel, while the neck cutoff pattern forms a suddenly abandoned channel. From upstream to downstream, the sedimentary pattern of the abandoned channel transforms from a chute cutoff pattern to a neck cutoff pattern, where the main controlling factors transition from the grain size and gradient to the flow and vegetation. An abandoned channel formed by a chute cutoff pattern consists mainly of siltstone, fine sandstone and thin gravel layers, which form a lithological-physical barrier. The abandoned channel formed by a neck cutoff pattern consists mainly of mudstone and argillaceous siltstone, forming a lithological barrier. Based on the amalgamation and structure of the reservoir architectural elements, the abandoned channel can be divided into three planar sedimentary patterns(crescent, semilune and horseshoe) for a single channel and five vertical sedimentary patterns for composite channels. 相似文献
7.
两类多河道河流的形式模式及河道稳定性比较 总被引：8，自引：0，他引：8
在多河道河流中，网状河流作为有别于分汊河流和辫状河流的河型而提出已经引起人们的注意，但它与分汊河流的区别常常被忽略。为了阐明二者的根本差别，力求从多河道形成模式上对二者进行比较研究。通过对长江下游分汊河流及荆江风状河流特定河段形成历史及方式的探索，提出河道内的江心洲化模式和河漫滩上的河道化模式分别是分汊河流和网状河流形成的基本途径。由此而决定了网状河道具有分汊河流更高的稳定性。 相似文献
8.
西江和北江三角洲区的水沙特点及河道演变特征 总被引：11，自引：0，他引：11
通过对珠江三角洲区有关水文泥沙资料的分析, 初步揭示了西江和北江在流速与流量、水位、含沙量、断面宽深比之关系方面的差别。结合河道平面及断面形态和河道冲淤特性, 探讨了其河型特点及成因。认为研究区西江为典型的网状河流, 而北江仍处于网状河流的发育初期。该区网状河流多河道的形成遵循冲裂机制, 人工堤围加速了河道沉积、抑制了河漫滩地的淤积, 从而使河道及河漫滩地的加积表现为不均一性。 相似文献
9.
江心洲在何种水动力条件下具有稳定的形态一直是河床演变学中的核心问题,采用河道形态变分分析方法,综合分析分汊型河流在水流连续方程、阻力方程、推移质输沙方程和总流能量方程控制下的自动调整机理。以长江中下游两汊不对称的江心洲为研究对象,将其形态概化为规则的等腰三角形,详细数理分析发现,主汊的分沙比大于分流比是这类江心洲达到平衡的必要条件。当分汊河道达到平衡状态时,江心洲的形态会随着汊道间水沙分配比例的调整而变化,且分流比与分沙比越接近,江心洲越窄长。另外,利用长江中游监利汊道的实测水沙资料对理论分析进行验证,结果表明,江心洲形态的理论计算值与相应的实测值符合程度较好,相对误差为9.0%左右。 相似文献
10.
RANSOME K. T. CORNEY† JEFFREY PEAKALL DANIEL R. PARSONS LIONEL ELLIOTT† KATHRYN J. AMOS JAMES L. BEST GARETH M. KEEVIL DEREK B. INGHAM† 《Sedimentology》2006,53(2):249-257
The planform patterns of meandering submarine channels and subaerial fluvial bends show many similarities that have given rise to strong analogies concerning the fluid dynamics of these channel types. Existing models of helical motion in open‐channel bends depict flow that is characterized by surface flow towards the outer bank, and basal flow towards the inner bank. This paper investigates and compares, through an analytical model and physical experiment, flows within fluvial meanders, and submarine channel bends that contain density‐driven gravity currents. The results indicate that the sense of helical motion can be reversed in submarine bends that contain density currents when compared with fluvial bends, and that the orientation of the helical flow is dependent on the vertical distribution of downstream velocity. Specifically, the sense of helical motion is reversed in bends when the maximum downstream velocity is near the bed, resulting in near‐bed flow towards the outer bank. These findings suggest that the dynamics of sediment transport and deposition in curved channels with such velocity profiles will be fundamentally different to those currently assumed from sinuous open‐channels. 相似文献
11.
为探究大型水利枢纽影响下分汊河道演变特征及其驱动机制,根据三峡水库下游的实测水文和地形资料,基于动态分流比对分汊河道进行了类别划分,在此基础上研究了主汊、支汊与洲头心滩的调整规律及其对水文过程的响应。结果表明:① 三峡水库蓄水后,坝下游分汊河道的洲头低滩均呈现萎缩,而汊河则表现为"主长支消"和"主消支长"并存的分异性规律;② 基于动态分流比的分汊河道类别划分方法,上述演变差异可归纳为枯水倾向汊河发展速率大于洪水倾向汊河的规律,且2008年之后洪水倾向汊河基本表现为淤积特征;③ 水文过程中洪水削减、中水持续时间增长是滩槽调整的驱动因素,汊河冲淤均是向着主支汊格局更加稳定的方向进行,并与流量变差系数减小的水文过程相适应。 相似文献
12.
Grain-size sorting within river bars in relation to downstream fining along a wandering channel 总被引：1，自引：0，他引：1
The textural variability of river bed gravels at bar scales is poorly understood, as are the relations between variability at this scale and at reach and river scales. Surface and subsurface grain‐size distributions were therefore examined at reach, bar and bedform scales along lower Fraser River, British Columbia, Canada. Grain‐size variations within compound bars are conditioned by longitudinal position, elevation and morphological setting. Surface and subsurface sediments tend to decrease in median size from bar head to bar tail by 33% and 17%, respectively. Sediment size is constrained at some upper limit that is inversely related to bar surface elevation and which is consistent with competence considerations. The surface sediments on unit bars are finer and better sorted than the bed materials in bar‐top channels and along the main bar edges. Secondary unit bars tend to have a lower sand content than other features, a consequence of sediment resorting. Individual unit bars and gravel sheets exhibit streamwise grain‐size fining and lee‐side sand deposition. Over time, significant amounts of cut and fill do not ipso facto cause changes in surface grain sizes; yet, sediment characteristics can change without any significant morphological adjustment taking place. At the reach scale there is a clear downstream fining trend, but local variability is consistently high due to within‐bar variations. The surface median grain‐size range on individual bars is, on average, 25% of that along the entire 50 km reach but is 68% on one bar. While the overall fining trend yields a downstream change in surface median size of 0·76 mm km?1, the average value for ‘head‐to‐tail’ size reduction on individual bars is 6·3 mm km?1, an order of magnitude difference that highlights the effectiveness of bar‐scale sorting processes in gravel‐bed rivers. Possibilities for modelling bar‐scale variability and the interaction of the different controls that are identified are discussed. 相似文献
13.
安哥拉深水水道地质知识库建立及应用 总被引：1，自引：0，他引：1
利用浅层(上新统)三维高频地震资料的剖面、切片和属性信息,对安哥拉陆坡区深水水道特征和定量关系进行研究,在复合水道和单一水道两个层次上建立了安哥拉地区浊积水道定量化地质知识库.研究结果表明:研究区单一水道活动方式类似于曲流河点坝模式,即单一水道仅沿侧向(垂直于古流向)整体迁移,不存在整体“下游扫动”分量,且在平面上其侧积复合体呈“同心半环状”,单一水道的砂体以垂向加积方式充填在轴部,厚度向边部减薄;单一水道的宽度与深度、弯曲弧长与弯曲度之间存在较好的正相关性;复合水道样式按照内部单一水道的活动方式分为(Ⅰ)侧向迁移、(Ⅱ)斜列迁移和(Ⅲ)摆动迁移三类模式,且(Ⅰ)类主要发育在高弯曲段(弯曲度>1.3),Ⅱ类和Ⅲ类主要发育在低弯曲段(1<弯曲度≤1.3);该地质知识库成功应用到实际三维地质建模中,具有推广价值.本文研究不仅可以完善深水水道定量分布模式,而且可以有效降低此类油田开发风险,具有理论和实际意义. 相似文献
14.
网状河流的构型、流量-宽深比关系和能耗率 总被引：6，自引：0，他引：6
网状河流作为一类新河型,已经受到研究者的关注,但对其研究还不充分.该研究基于目前已经报道过的资料及新近取得的研究成果,从河流构型、河道过水断面宽深比与流量关系及能耗率等方面对该河型展开论述,期望引起大家对该河型的兴趣.网状河流在许多方面表现出了独有的特色.从平面构型来看,它以相互连通的多河道围绕非常稳定的泛滥盆地为特征,其中泛滥盆地上植被发育、沼泽湖泊可见.从河道纵、横剖面来看,它具有非常小的河道比降和一般小于40的河道宽深比,总体上属于各类河型中最小的.从沉积体系的剖面构型来看,它以多个孤立的河道砂体"漂浮"在细粒泥质沉积物中为特征.在河道过水断面宽深比与流量的半对数图中可见,其宽深比随流量的增大而减小,并且其散点位于各类河流的最下部.由于其河道比降一般很小,多河道体系中的单个河道的流量相对于其决口前的老河道显然较小,从而其能耗率就相对很小.文中所讨论到的长江三口分流网状河道:东松滋河、西松滋河、虎渡河、藕池河、北藕池河和松澧合流,其能耗率分别为3.0 W/m2,5.5 W/m2,2.8 W/m2,6.4 W/m2,3.7 W/m2和2.7 W/m2,显然都小于10 W/m2,这与长江主河道在枝江附近的140 W/m2相比,差两个数量级.所有这些特征都预示着网状河流与以长江中下游为代表的分汊河流之间有着完全不同的特性,与其他河型更是大相径庭. 相似文献
15.
TAKEO NAKAGAWA 《Sedimentology》1983,30(1):117-127
ABSTRACT An account of stream meandering and river morphology is given for five experiments, each having different conditions at the wetted perimeter of the channel.
On the basis of the present experiments, it is proposed that a necessary (but insufficient) condition for the formation of stream meandering is an appropriately small ratio of total bank shear force to total bed shear force, both per unit length downstream . In mathematical form, the criterion is expressed by τs and τs are an average bank stress and bed stress, respectively, and p s and p b b are an average bank wetted perimeter and bed wetted perimeter of a half-channel, respectively. The value of α is evaluated by Kinoshita's (1957) experiment and others.
It is also found that the flow pattern, channel morphology and sand waves on the bed are dependent upon the boundary conditions at the wetted perimeter. 相似文献
On the basis of the present experiments, it is proposed that a necessary (but insufficient) condition for the formation of stream meandering is an appropriately small ratio of total bank shear force to total bed shear force, both per unit length downstream . In mathematical form, the criterion is expressed by τ
It is also found that the flow pattern, channel morphology and sand waves on the bed are dependent upon the boundary conditions at the wetted perimeter. 相似文献
16.
陆相深水重力流水道的类型细分及其沉积模式是制约其油气勘探开发的重要因素,但研究程度低。通过对鄂尔多斯盆地南缘瑶曲铁路桥剖面三叠系延长组实测、水道形态参数统计及岩相、粒度等分析,开展了湖相重力流水道的沉积特征、沉积过程及沉积模式研究。结果表明:(1)研究区内可识别出4期复合水道,主要为洪水重力流成因。根据其内部单一水道及单砂体形态特征、岩相组成,将其细分为沉积型和过渡型两类。(2)剖面下部2期复合水道为沉积型,以悬浮载荷成因岩相为主,常见块状净细砂岩、薄层泥岩岩相组合和鲍马序列岩相组合;上部2期复合水道为过渡型,岩相以底床载荷与悬浮载荷共存为特征,自下而上以交错层理细砂岩或叠瓦状泥砾细砂岩与含泥砾/泥岩撕裂屑块状细砂岩、平行层理粗粉砂岩及薄层泥岩的岩相组合为特征。(3)结合单一水道规模及其相互关系,建立了区内过渡、沉积型重力流水道的半定量沉积模式。过渡型水道内部侵蚀与沉积作用共存,单一水道宽度小、宽厚比低,呈透镜状,水道间切割性强,砂体横向稳定性较低,表现出不定向叠加、侧向拼接样式;沉积型水道内部由沉积作用主导,单一水道宽度较大、宽厚比较高,呈似板状—透镜状,砂体横向稳定性较高,表现出稳定的垂向加积样式。 相似文献
17.
《Sedimentology》2018,65(3):702-720
Gravel‐bed rivers can accommodate changes in sediment supply by adjusting their bed topography and grain size in both the downstream and cross‐stream directions. Under high supply aggradational conditions, this can result in spatially non‐uniform stratigraphic patterns, and the morphodynamic influence of heterogeneous stratigraphy during subsequent degradational periods is poorly understood and has not been studied through physical modelling. A flume experiment was conducted to analyse channel response where alternate bars were developed in a gravel–sand mixture under constant discharge and sediment supply before two supply increases led to the development of heterogeneous stratigraphy beneath alternate bars. The supply was then reduced back to the initial supply rate, causing degradation through that self‐formed stratigraphy. Stratigraphic samples were collected, and the bed topography and flow depth were measured frequently, which were used with a two‐dimensional hydrodynamic model to characterize flow conditions. Migrating alternate bars stabilized during the first equilibrium phase, creating bed surface sorting patterns of coarse bar tops and fine pools. During the first supply increase, the bars remained stable as the pools aggraded. During the second supply increase, the pools aggraded further, causing the boundary shear stress over the bar tops to increase until the bars gained the capacity to migrate and eventually stabilize in new locations. As aggradation occurred, the original sediment sorting patterns were preserved in the subsurface. During the degradational phase, the pools experienced incision and the bars eroded laterally, but this lateral erosion ceased when coarse sediment previously deposited during the bar‐building phase became exposed. The results suggest that if a sediment supply increase is capable of filling the pools, it can cause stable bars to migrate and the bed to be reworked. These findings also show that heterogeneous stratigraphy can play an important role in determining whether bars persist or disappear after a sediment supply reduction. 相似文献
18.
The variability of critical shear stress, friction angle, and grain protrusion in water-worked sediments 总被引：3，自引：0，他引：3
JAMES W. KIRCHNER WILLIAM E. DIETRICH† FUJIKO ISEYA‡ HIROSHI IKEDA‡ 《Sedimentology》1990,37(4):647-672
The erodibility of a grain on a rough bed is controlled by, among other factors, its relative projection above the mean bed, its exposure relative to upstream grains, and its friction angle. Here we report direct measurements of friction angles, grain projection and exposure, and small-scale topographic structure on a variety of water-worked mixed-grain sediment surfaces. Using a simple analytical model of the force balance on individual grains, we calculate the distribution of critical shear stress for idealized spherical grains on the measured bed topography. The friction angle, projection, and exposure of single grain sizes vary widely from point to point within a given bed surface; the variability within a single surface often exceeds the difference between the mean values of disparate surfaces. As a result, the critical shear stress for a given grain size on a sediment surface is characterized by a probability distribution, rather than a single value. On a given bed, the crtitical shear stress distributions of different grain sizes have similar lower bounds, but above their lower tails they diverge rapidly, with smaller grains having substantially higher median critical shear stresses. Large numbers of fines, trapp.ed within pockets on the bed or shielded by upstream grains, are effectively lost to the flow. Our calculations suggest that critical shear stress, as conventionally measured, is defined by the most erodible grains, entrained during transient shear stress excursions associated with the turbulent flow; this implies a physical basis for the indeterminacy of initial motion. These observations suggest that transport rate/shear stress relationships may be controlled, in part, by the increasing numbers of grains that become available for entrainment as mean shear stress increases. They also suggest that bed textures and grain size distributions may be controlled, within the constraints of an imposed shear stress and sediment supply regime, by the influence of each size fraction on the erodibility of other grain sizes present on the bed. 相似文献
19.
三峡水库2003年6月蓄水运用后,下游河道水沙过程已发生大幅变化,对于岸滩抗冲性较弱的荆江河道来说,河道的横向调整过程势必受到影响。采用考虑岸滩崩塌的河势研究数值模型,针对三峡水利枢纽工程运行所引发的水沙变异过程,初步探讨了荆江典型河道横向调整及河势变化对水沙条件变化的响应。对于下荆江石首河段来说,来沙减少后,冲刷加剧,局部河岸坍塌及平面变形加剧,主要发生在受弯道水流顶冲的位置,但河势演变趋势及平面变形总体上基本一致,并未发生较大变化。对于上荆江沙市—新厂河段来说,来沙量减小后,河道平面变形幅度总体上减小,局部最大减幅可达50%左右。 相似文献
20.
Benjamin T. Cardenas David Mohrig Timothy A. Goudge Cory M. Hughes Joseph S. Levy Travis Swanson Jasmine Mason Feifei Zhao 《Sedimentology》2020,67(7):3655-3682
Many published interpretations of ancient fluvial systems have relied on observations of extensive outcrops of thick successions. This paper, in contrast, demonstrates that a regional understanding of palaeoriver kinematics, depositional setting and sedimentation rates can be interpreted from local sedimentological measurements of bedform and barform strata. Dune and bar strata, channel planform geometry and bed topography are measured within exhumed fluvial strata exposed as ridges in the Ruby Ranch Member of the Cretaceous Cedar Mountain Formation, Utah, USA. The ridges are composed of lithified stacked channel belts, representing at least five or six re-occupations of a single-strand channel. Lateral sections reveal well-preserved barforms constructed of subaqueous dune cross-sets. The topography of palaeobarforms is preserved along the top surface of the outcrops. Comparisons of the channel-belt centreline to local palaeotransport directions indicate that channel planform geometry was preserved through the re-occupations, rather than being obscured by lateral migration. Rapid avulsions preserved the state of the active channel bed and its individual bars at the time of abandonment. Inferred minimum sedimentation durations for the preserved elements, inferred from cross-set thickness distributions and assumed bedform migration rates, vary within a belt from one to ten days. Using only these local sedimentological measurements, the depositional setting is interpreted as a fluvial megafan, given the similarity in river kinematics. This paper provides a systematic methodology for the future synthesis of vertical and planview data, including the drone-equipped 2020 Mars Rover mission, to exhumed fluvial and deltaic strata. 相似文献