Geomorphology最新文献_第6页

Using paired Schmidt Hammer and terrestrial cosmogenic surface exposure dating to study the timing and style of rockfalls in the Rough River Basin, Kentucky: Results, constraints, and possible mechanisms 使用配对的施密特·哈默和地球宇宙表面暴露年代法研究肯塔基州Rough河流域岩崩的时间和风格：结果、限制和可能的机制

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-07 DOI: 10.1016/j.geomorph.2025.110118

Daria Khashchevskaya , Jason M. Dortch , Lewis A. Owen , Paula Figueiredo

The setting of weak shales underlying heavily fractured sandstone caprock, coupled with the wet environmental conditions along the valley slopes of the Rough River Basin in north-central Kentucky, has led to massive rockfalls composed of clusters of sandstone boulders. However, the exact mechanisms of cliff retreat and sediment accumulation due to mass movement in that region remained unclear. In addition, the frequency and timing of these mass movement events are uncertain. To better understand mass movement mechanisms, we used the Schmidt Hammer exposure dating (SHED) technique and terrestrial cosmogenic nuclide dating on two sites in the Rough River basin, “Home Tucker” and “Linda Paul.” The results suggest that the degradation mechanism of sandstone cliffs by mass movement varies due to local geology and climate change. The Home Tucker site exhibits boulder accumulation through rockfall during the Early Holocene (10.6 ± 1.0 to 43.9 ± 3.0 ka), precluding the estimation of a cliff retreat rate. In contrast, the Linda Paul site exhibits block sliding and toppling, with detachment events spanning from 21 ± 1.6 to 66.8 ± 5.4 ka, and an estimated cliff retreat rate of 0.17 ± 0.09 mm/yr for Home Tucker site and 0.22 ± 0.1 mm/yr for the Linda Paul site. These findings suggest that detachment events occurred more frequently during the last glacial maximum, likely due to freeze-thaw processes or rapid climate change. With only one boulder dated to the Holocene, warming and a relatively stable climate during the Holocene have likely slowed cliff degradation. Attempts to develop a reliable SHED calibration curve were hindered by no correlation (r² = 0.1) between ¹⁰Be age and SHED rebound measurement. This lack of correlation is likely due to variable vegetation cover, moisture inconsistencies, temporally non-linear and spatially heterogeneous weathering of quartz arenite, inheritance of weathering from before rock fall, and bed-dependent variations in strength.

在肯塔基州中北部的Rough River流域，脆弱的页岩位于严重断裂的砂岩盖层之下，再加上河谷斜坡的潮湿环境，导致了由砂岩巨石群组成的大规模落石。然而，由于该地区的质量运动，悬崖退缩和沉积物堆积的确切机制尚不清楚。此外，这些大规模运动事件的频率和时间是不确定的。为了更好地理解质量运动机制，我们在Rough河流域的“Home Tucker”和“Linda Paul”两个地点使用了Schmidt Hammer暴露测年（SHED）技术和陆地宇宙形成核素测年。结果表明，砂岩崖体运动的退化机制因局部地质和气候变化而异。Home Tucker遗址显示，在全新世早期（10.6±1.0至43.9±3.0 ka），岩石通过落石堆积，排除了悬崖退缩率的估计。相比之下，Linda Paul遗址表现出块体滑动和倾倒，分离事件跨度为21±1.6至66.8±5.4 ka，估计Home Tucker遗址的悬崖后退率为0.17±0.09 mm/年，Linda Paul遗址为0.22±0.1 mm/年。这些发现表明，拆离事件在末次盛冰期发生的频率更高，可能是由于冻融过程或快速的气候变化。只有一块巨石可以追溯到全新世，全新世期间的变暖和相对稳定的气候可能减缓了悬崖的退化。由于10Be年龄与SHED回弹测量值之间没有相关性（r2 = 0.1），建立可靠的SHED校准曲线的尝试受到阻碍。这种相关性的缺乏可能是由于不同的植被覆盖、水分不一致、石英砂岩的时间非线性和空间非均质风化、岩石坠落前的风化继承以及强度的层依赖性变化。

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引用次数: 0

Rock glacier velocity monitored by annual in-situ geodetic surveys: Long-term challenges, solutions and suggestions 岩石冰川速度监测的年度原位大地测量：长期挑战，解决方案和建议

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-05 DOI: 10.1016/j.geomorph.2025.110117

Andreas Kellerer-Pirklbauer , Xavier Bodin , Reynald Delaloye , Christophe Lambiel , Isabelle Gärtner-Roer , Bodo Damm , Atsushi Ikeda , Viktor Kaufmann , Karl Krainer , Roberto Seppi , Cristian Scapozza , Martin Stocker-Waldhuber , Emmanuel Thibert

We provide an overview of geodetic survey designs conducted on 43 rock glaciers (RG) in the European Alps, embed these in an overview of the pioneering phase of monitoring RG movement, and compare our approaches with other studies. Different in-situ geodetic approaches used for the annual survey of RG velocity (RGV) and RG frontal advance (RGA) are examined. Geodetic-based RGV monitoring in the Alps started in 1918 and RGA in 1921. RGV is an associated parameter of the Essential Climate Variable “Permafrost” since 2022. Nowadays, satellite-based positioning or classic measurements with a total station are used for in-situ geodetic surveys. The total number of surveyed boulders at the 43 RGs varies from 1 to 206. In most cases, only a part of these points is considered as “reference points” used to calculate the RGV value of RG units. The density of reference points for RGV calculation ranges from 27.5 to 1143 pts./km². For RGV monitoring using annual geodetic surveys, we suggest: (a) selecting a RG where multi-decennial monitoring seems to be feasible, (b) distributing uniformly observation points over the entire RG unit of interest along either profiles or well-distributed boulders, (c) repeating measurements always at the same time of the year (September), (d) site-RGV-averaging using all data points, (e) site-RGV-averaging using only the survey markers considered to be the most suitable for long-term monitoring, (f) providing additional statistical information of these points and in particular of the central flowline, and (g) securing long-term storage of original data, metadata and results.

我们概述了在欧洲阿尔卑斯山的43个岩石冰川（RG）上进行的大地测量设计，将这些设计嵌入到监测RG运动的先驱阶段的概述中，并将我们的方法与其他研究进行了比较。研究了不同的大地测量方法在RG速度（RGV）和RG锋面推进（RGA）年度测量中的应用。阿尔卑斯山基于大地测量学的RGV监测始于1918年，RGA始于1921年。RGV是2022年以来基本气候变量“永久冻土”的相关参数。目前，原位大地测量主要采用卫星定位或全站仪的经典测量方法。在43个地质勘探区所调查的巨石总数由1个至206个不等。在大多数情况下，这些点中只有一部分被视为“参考点”，用于计算RG单位的RGV值。RGV计算参考点密度为27.5 ~ 1143 pts./km2。对于利用每年的大地测量监测地表生物，我们建议：(a)选择一个似乎可以进行多年监测的RG， (b)沿着剖面或分布均匀的巨石在整个感兴趣的RG单元上均匀分布观测点，(c)总是在一年的同一时间（9月）重复测量，(d)使用所有数据点进行场址- rgv平均，(e)仅使用被认为最适合长期监测的调查标记进行场址- rgv平均，(f)提供这些点，特别是中央管线的额外统计信息；(g)确保原始数据、元数据和结果的长期存储。

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引用次数: 0

A conceptual model of bed deformation and bank erosion in the bifurcated reaches of the Middle Yangtze River 长江中游分岔河段河床变形与河岸侵蚀的概念模型

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-03 DOI: 10.1016/j.geomorph.2025.110114

Heng Zhu , Junqiang Xia , Shanshan Deng , Meirong Zhou

The evolution of bifurcated reaches is complicated owing to flow and sediment diversion at bifurcation and subsequent differential branch deformation. Previous numerical studies have mostly focused on short-term bed deformation in bifurcated reaches, overlooking the process of bank erosion, and their practical application is often limited by high computational costs and the necessity for high-precision topographic data. Therefore, a conceptual model was proposed to simultaneously simulate bank erosion and bed deformation processes of different branches, calibrated and verified using the measurements from two typical bifurcated reaches in the Middle Yangtze River. Results show that: (i) the main branch experienced scouring, while the secondary branch showed deposition or slight scouring, with the calculated cross-sectional profiles closely matching the measurements; (ii) the mid-channel bar adjacent to the main branch exhibited more intense bank erosion due to a higher flow diversion ratio, with a bank retreat width of about 10 m, further promoting the development of the main branch; and (iii) the fluvial erosion intensity of incoming flow-sediment conditions showed a positive correlation with the deformation difference between the branches, and short branches with small bifurcation angles experienced stronger erosion compared with long branches. Besides, engineering interventions that rose the riverbed elevation at the main branch entrance by 1 m could switch the roles of the main and secondary branches, potentially promoting the transition from a two-branched system to a single-channel system.

由于分叉处水流泥沙的分流和随后的差异分支变形，分叉河段的演化十分复杂。以往的数值研究大多集中在分岔河段的短期河床变形，忽略了河岸侵蚀过程，其实际应用往往受到计算成本高和需要高精度地形数据的限制。为此，提出了一个同时模拟不同支流侵蚀和河床变形过程的概念模型，并利用长江中游两个典型分叉河段的实测数据进行了标定和验证。结果表明：(1)主支流发生冲刷，次支流发生淤积或轻微冲刷，计算断面与实测结果吻合较好；(2)靠近主支流的中沙坝由于导流比较大，冲岸较为强烈，退岸宽度约为10 m，进一步促进了主支流的发育；(3)来水流沙条件的河流侵蚀强度与支流间的变形差呈正相关，分叉角小的短支流比长支流受侵蚀更强。此外，将主支流入口处的河床标高提高1米的工程干预措施可以转换主支流和次级支流的角色，从而有可能促进从双支流系统向单通道系统的转变。

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引用次数: 0

Modification of offshore wind flow and aeolian sand transport by artificial foredunes 人工前沙丘对近海风流和风沙输运的影响

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-11-26 DOI: 10.1016/j.geomorph.2025.110106

Antoine Lamy , Nicolas Robin , Patrick A. Hesp , Thomas A.G. Smyth , Camille René , Olivier Raynal , Bertil Hebert

Airflow dynamics and aeolian sand transport under offshore wind conditions have primarily been examined over relatively large coastal dunes, where dune morphology significantly alters flow structure and sediment pathways. In contrast, the role of smaller-scale, anthropogenically constructed coastal sand dunes, remains relatively understudied. This study investigates airflow patterns and sand transport over a low (<2.5 m) artificial foredune in Leucate (South of France), exposed to dominant offshore winds. A high resolution network of anemometers and aeolian sand traps was deployed along a cross-shore transect during four field campaigns. Results indicate that the direction of incident offshore winds generated distinct patterns of airflow and sediment transport from the dune's lee slope to the beach. When wind approached within 20° of crest-normal, flow separation occurred on the lee side, with wind speeds reduced to 10–20 % of crest values. For angles >20°, flow remained attached but deviated alongshore, with wind speeds reaching 35–50 % of crest values at the dune seaward toe. Wind velocity consistently increased seaward, enhancing sand transport toward the berm, with maximum transport rates exceeding 300 kg/m/h. This seaward-directed transport contributed to a negative sediment budget under persistent offshore wind dynamics. These findings highlight the capacity of small, artificial dunes to modify offshore wind dynamics and sediment pathways, with implications for dune management and coastal sediment budgets.

海风条件下的气流动力学和风成沙输运主要在相对较大的海岸沙丘上进行了研究，沙丘形态显著改变了流动结构和沉积路径。相比之下，小规模的、人为建造的海岸沙丘的作用，研究仍然相对不足。本研究调查了位于法国南部吕盖特（Leucate）的一个低（<；2.5米）人工前沙丘上的气流模式和沙尘运输，该沙丘暴露在主要的海上风中。在四次野外活动中，沿海岸样带部署了一个高分辨率风速计和风沙陷阱网络。结果表明，海风入射方向对沙丘背风坡向海滩的气流输沙有明显的影响。当风速接近峰正线20°以内时，背风侧发生气流分离，风速降至峰正线的10 - 20%。在坡度>；20°时，气流保持附着，但沿岸偏离，风速达到沙丘向海趾峰值的35 - 50%。海风方向风速持续增加，加强了沙向护堤的输沙，最大输沙率超过300 kg/m/h。在持续的海上风动力下，这种向海的运输导致了负泥沙收支。这些发现强调了小型人工沙丘改变海上风动力和沉积路径的能力，对沙丘管理和海岸沉积物预算具有重要意义。

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引用次数: 0

Temporal and spatial dynamics of urban stream geomorphology: The role of effective imperviousness and development age 城市水系地貌的时空动态：有效不透水性和发展年龄的作用

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-30 DOI: 10.1016/j.geomorph.2025.110155

Lukman A. Soboyejo , Kathryn L. Russell , Tim D. Fletcher

Urbanisation has been widely studied for its impact on stream channel geomorphology, primarily using space-for-time substitution approaches. However, continuous monitoring of urban geomorphic responses, to understand the temporal dynamics and influence of development age, remains underexplored within this framework. In this study, we combined repeated field observations collected 13 years apart with land cover analysis to assess geomorphic change across a gradient of urbanisation. We addressed three research questions: (i) to what extent do space-for-time substitution interpretations align with directly observed changes in stream channel morphology, and are post-study changes in stream channels consistent with earlier observations? (ii) how has the change in the extent of urbanisation over the study period directly influenced observed changes in stream channel morphology? (iii) at what level of urban development is stream incision most severe (i.e., does channel morphology stabilise during the latter stages of urban development)? We found that predictions made through space-for-time substitution in 2011 (i.e. regression models) were largely consistent with relationships observed in 2024 following further urbanisation of the catchments. However, change in geomorphic attributes at each site over the 13-year period were not significantly related to change in effective impervious cover (EI), possibly due to lag in geomorphic responses to ongoing urbanisation, along with the presence of hardpoints such as rock protection in the urbanised streams. Notably, several individual sites did show signs of active channel adjustment; all of these sites had moderate levels of urbanisation (<30 % EI), which had developed relatively recently (in the last 25 years). Severe channel incision was also observed within this range, suggesting a critical window for morphological instability. Whether channels eventually stabilise (without heavy intervention to harden channels) remains uncertain. Overall, the findings reinforce the importance of validating space-for-time substitution approaches through repeated observations to better develop more reliable urban channel evolution and stream management strategies.

城市化对河道地貌的影响已被广泛研究，主要采用时空替代方法。然而，在这一框架内，对城市地貌响应的持续监测，以了解发展年龄的时间动态和影响，仍未得到充分探索。在这项研究中，我们将相隔13年的重复实地观测与土地覆盖分析相结合，以评估城市化梯度下的地貌变化。我们解决了三个研究问题：(i)时空替代解释在多大程度上与直接观察到的河流河道形态变化相一致，以及研究后的河流河道变化与早期观察结果一致？（ii）在研究期间，城市化程度的变化如何直接影响已观察到的河道形态变化？（iii）在城市发展的哪个阶段，河流切割最为严重（即，在城市发展的后期，河道形态是否趋于稳定）？我们发现，2011年通过时空替代（即回归模型）所做的预测与流域进一步城市化后2024年观察到的关系基本一致。然而，在13年的时间里，每个地点的地貌属性变化与有效不透水覆盖（EI）的变化没有显著相关性，这可能是由于地貌对持续城市化的响应滞后，以及城市化溪流中存在岩石保护等挂载点。值得注意的是，几个单独的网站确实显示出积极的渠道调整迹象；所有这些地点都有中等水平的城市化（30% EI），这些城市化发展相对较晚（过去25年）。在这个范围内也观察到严重的通道切口，提示形态不稳定的关键窗口。渠道最终是否会稳定（不需要大量干预来强化渠道）仍不确定。总的来说，研究结果强调了通过反复观察验证空间替代时间方法的重要性，以更好地制定更可靠的城市通道演变和流管理策略。

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引用次数: 0

Reduced channel migration rates in a braided reach owing to upstream damming 由于上游筑坝减少了辫状河段的河道迁移速率

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-21 DOI: 10.1016/j.geomorph.2025.110142

Yifei Cheng , Junqiang Xia , Meirong Zhou , Shanshan Deng , Xixi Lu

Braided reaches are the most unstable channel type, prone to rapid and frequent migration. The construction of upstream dams significantly alters the downstream flow–sediment regime, leading to substantial variations in channel migration rates, which poses critical challenges for river management and training works. This study examines the braided reach of the Lower Yellow River, which exhibits intense channel adjustments and diverse migration patterns, serving as an ideal site to evaluate decadal-scale changes in thalweg and centerline migration rates. Based on long-term remote sensing imagery and cross-sectional profile measurements, results indicate that (i) a significant spatial and temporal reduction in channel migration rates has occurred. The average rate of thalweg migration in the braided reach reduced from 229 m/a during the pre-dam stage to 166 m/a during the post-dam stage, accompanied with the rate of centerline migration reducing from 122 to 76 m/a. The middle sub-reach was always the most active in the braided reach, but the spatial difference of channel migration rate reduced by around 20 % during the post-dam stage; (ii) the thalweg migration rate generally exceeded or equaled the centerline migration rate, but the discrepancy between these two types spatially varied. The smallest difference was observed in the upper sub-reach, and the largest in the middle sub-reach; and (iii) a reduction in channel migration rate was reconciled with the significant decrease in incoming sediment coefficient and the increase in bankfull depth caused by upstream damming, with the incoming sediment coefficient identified as the dominant controlling factor.

辫状河段是最不稳定的河道类型，易于快速和频繁的迁移。上游水坝的建设极大地改变了下游的流沙状态，导致河道迁移速率的实质性变化，这对河流管理和治理工程提出了严峻的挑战。本研究考察了黄河下游辫状河段，该河段表现出强烈的河道调整和多样化的迁移模式，可作为评估thalweg和中心线迁移率年代际变化的理想地点。基于长期遥感影像和断面剖面测量的结果表明：(1)河道迁移速率在时空上显著降低。辫状河段平均沙重迁移速率由坝前阶段的229 m/a降至坝后阶段的166 m/a，中心线迁移速率由122 m/a降至76 m/a。辫状河段中段始终是最活跃的河段，但在坝后阶段，河道迁移速率的空间差异减小了20%左右；②海重迁移速率总体上大于或等于中心线迁移速率，但两者之间的差异存在空间差异。上游差异最小，中游差异最大；(3)河道迁移速率的减小与上游筑坝引起的入沙系数的显著减小和岸深的增加相一致，入沙系数是主要的控制因素。

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引用次数: 0

Early-onset of rapid deposition rates of the Mangshan loess challenges the classical hypothesis of full Yellow River connection during the late Pleistocene 芒山黄土早发的快速沉积速率挑战了黄河在晚更新世完全贯通的经典假说

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-24 DOI: 10.1016/j.geomorph.2025.110149

Yingyong Chen , Xiaodong Miao

Understanding the origin and evolution of the Yellow River is not only crucial for understanding the geomorphic and climatic history, but also pivotal due to its historical significance and ecological impact on China's environment. However, the timing of the full connection of the Yellow River, as a critical event in the genesis of this major river system, is still debated continuously. Among various competing hypotheses, the abrupt increase of deposition rates following paleosol 2 (S2 of Chinese loess sequence, starting at about 0.245 Ma at the late Pleistocene) of the Mangshan loess was considered as major evidence of the late Pleistocene hypothesis, which attributes this increase to a sudden connection of the Yellow River. Here we scrutinized the stratigraphy of the Mangshan loess and identified abrupt increase of deposition rates occurring significantly earlier (at layers L11, S10, S9, L8, L7, L3) than S2, undermining the late Pleistocene hypothesis of the Yellow River genesis in the perspective of time. Moreover, we attribute the abrupt deposition rates to episodic gully erosion of the Loess Plateau, a mechanism distinct from the late Pleistocene full-river connection hypothesis. Therefore, the hypothesis that the Yellow River fully connected during the late Pleistocene is mechanistically unsupported, suggesting this connection likely occurred much earlier than 0.245 Ma.

了解黄河的起源和演变不仅对了解地貌和气候历史至关重要，而且由于其历史意义和对中国环境的生态影响而至关重要。然而，作为这一主要水系形成过程中的一个关键事件，黄河完全贯通的时间仍然存在争议。在各种相互竞争的假说中，从晚更新世约0.245 Ma开始的古土壤2（中国黄土序列S2）沉积速率的突然增加被认为是晚更新世假说的主要证据，该假说将这种增加归因于黄河的突然连接。通过对芒山黄土地层的研究，发现其沉积速率的急剧增加（L11、S10、S9、L8、L7、L3层）明显早于S2层，从时间上破坏了黄河成因的晚更新世假说。此外，我们将突变沉积速率归因于黄土高原的幕式沟蚀，这一机制与晚更新世全河连接假说不同。因此，黄河在晚更新世完全连通的假设在力学上是不支持的，表明这种连接可能发生在0.245 Ma之前。

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引用次数: 0

What is the maximum elevation mountains can reach on Earth, the Moon, and Mars? 地球、月球和火星上山脉的最高海拔是多少？

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-21 DOI: 10.1016/j.geomorph.2025.110144

Eulogio Pardo-Igúzquiza , Peter Dowd

The purpose of this paper is to compare the maximum theoretical and actual height of mountains on the Earth, Moon and Mars. This comparison requires a new definition of a mountain in which the reference to a global vertical datum is replaced by a local datum that is used for each topographic positive relief. Submarine topographies on Earth are also included as mountains. Although the Moon is the most likely to have the tallest mountains it has not had the effective geological processes required for mountain building. On Mars there is a high similarity between the maximum theoretical height and the heights of its giant volcanoes. On Earth, the geological factors of isostasy, fluvial and glacial erosion prevent mountains reaching their maximum theoretical height. On the Moon the highest mountains have been built by impact tectonics, whereas on Earth and Mars volcanism is the most efficient way of building a single mountain.

本文的目的是比较地球、月球和火星上山脉的最大理论高度和实际高度。这种比较需要对山进行新的定义，其中对全球垂直基准面的参考被用于每个地形正起伏的当地基准面所取代。地球上的海底地形也包括在山脉中。尽管月球最有可能拥有最高的山脉，但它还没有形成造山所需的有效地质过程。在火星上，最大理论高度和巨大火山的高度非常相似。在地球上，地壳均衡、河流和冰川侵蚀等地质因素阻碍了山脉达到最大理论高度。在月球上，最高的山脉是由撞击构造形成的，而在地球和火星上，火山作用是形成一座山的最有效方式。

引用次数: 0

Effects of sediment connectivity changes on channel evolutionary trajectory: the case study of the Taro and Ceno rivers in the Northern Apennines (Italy) 沉积物连通性变化对河道演化轨迹的影响——以意大利亚平宁北部塔罗河和奇诺河为例

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-08 DOI: 10.1016/j.geomorph.2025.110131

Sharon Pittau , Vittoria Scorpio

The post-1950s evolutionary trajectories of the Taro and Ceno rivers (Northern Apennines, Italy) were investigated, focusing on the correlation between channel adjustments and sediment alterations. The specific aims were to: i) highlight similarities and dissimilarities between the evolutionary trajectories of the two rivers; ii) assess the role of sediment connectivity decrease caused by land use changes along the hillslopes, and iii) evaluate the impact of gravel mining.

Changes in active channel width and bed level were quantified using multi-temporal orthophotos (1954–2020) and topographical cross-sections. Land use dynamics were reconstructed through multi-temporal land cover maps, and changes in structural sediment connectivity were assessed by applying the Index of Connectivity (IC). Evolution of landslide-prone areas was analysed to estimate changes in sediment supply, and the influence of anthropogenic activities was also considered through mapping gravel mining areas and in-channel works.

Results showed progressive afforestation, after the 1950s in the Ceno and after the 1970s in the Taro basin, with decreases in landslide-prone areas and IC. Hillslope stabilization caused a decrease in sediment supply to both channels, with subsequent channel narrowing and bed incision (−50 % and −3.3 m in the Taro and −38 % and −2.5 m in the Ceno, respectively). More intense morphological changes in the Taro, especially between 1954 and 1976, were linked to the intense gravel mining activity, completely absent along the Ceno. The combined effects of catchment-scale afforestation and reach-scale gravel extraction therefore played a key role in shaping the dissimilarities in the evolutionary trajectories between the two rivers.

研究了意大利亚平宁北部塔罗河和奇诺河在20世纪50年代后的演变轨迹，重点研究了河道调整与沉积物变化之间的相关性。具体目的是：1)强调两条河流演化轨迹的异同；Ii)评估沿坡土地利用变化导致的沉积物连通性下降的作用；iii)评估砾石开采的影响。利用多时相正射影像（1954-2020）和地形剖面量化了活跃水道宽度和河床水平的变化。通过多时相土地覆被图重构土地利用动态，应用连通性指数（IC）评价结构沉积物连通性变化。通过分析滑坡易发区的演变来估计泥沙供应的变化，并通过绘制砾石矿区和河道内工程来考虑人为活动的影响。结果表明，20世纪50年代和70年代后，在切诺流域和塔罗流域，渐进式造林减少了滑坡易发区和IC。山坡稳定导致两个河道的泥沙供应减少，随后河道变窄和河床切割（分别为- 50%和- 3.3 m，分别为- 38%和- 2.5 m）。特别是在1954年至1976年之间，塔罗河更剧烈的形态变化与激烈的砾石开采活动有关，而在Ceno河沿岸则完全没有。因此，流域尺度的造林和河段尺度的砾石开采的综合效应在形成两条河流进化轨迹的差异中发挥了关键作用。

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引用次数: 0

Deep-seated cave inception and shallow sulfuric acid maze cave genesis in Southern Irecê Basin, São Francisco Craton (Brazil) 巴西<e:1>圣弗朗西斯科克拉通Irecê盆地南部深层溶洞形成与浅层硫酸迷宫溶洞成因

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2026-02-15 Epub Date: 2025-12-10 DOI: 10.1016/j.geomorph.2025.110126

Philippe Audra , Luca Pisani , Marco Antonellini , Francisco Hilario R. Bezerra , Augusto S. Auler , Vincenzo La Bruna , Giovanni Bertotti , Fabrizio Balsamo , Cayo C.C. Pontes , Rebeca S. Lima , Marjan Temovski , Xianfeng Wang , Jo De Waele

Ioiô Cave is a 4.7 km long maze cave in the southern tip of the Irecê Basin (Bahìa, Brazil), and although still actively forming today, it hosts signs of a long speleogenetic history. Deep rising hydrothermal fluids weathered the carbonates, creating dark ghost-rocks and quartz and dolomite veins, mainly in the anticlinal hinges and below the siliciclastic seals. This silicification, although not directly dated, is probably associated with the end of the Brasiliano-age tectono-thermal activity (Lower Cambrian) based on isotopic and trace element data and regional tectonic correlations. Since the Plio-Quaternary, the progressive exhumation of the carbonate reservoir increasingly favored the introduction of meteoric oxygen-rich water from the surface, causing sulfide oxidation at shallow aquifer depth. The CO₂ produced by Sulfuric Acid Speleogenesis (SAS) rose along fractures and degassed at shallow depth, producing carbonic speleogenesis close to the water table. This carbonic speleogenesis, probably still active, produced a maze network, by horizontal diffusion of aggressive fluids from the feeders. Surface breaching increased air flow activating degassing and supersaturation of the basins, with deposition of subaqueous calcite shelves, carved with bubble trails resulting from CO₂ degassing related to still-ongoing pyrite oxidation (localized SAS).

Ioiô洞穴是位于Irecê盆地（Bahìa，巴西）南端的一个长4.7公里的迷宫洞穴，尽管今天仍在活跃地形成，但它拥有悠久的洞穴形成历史的迹象。深层上升的热液流体风化了碳酸盐，形成了黑色的鬼岩和石英白云岩脉，主要在背斜铰链和硅质密封下面。这种硅化作用虽然不能直接确定年代，但根据同位素和微量元素数据以及区域构造对比，可能与brasiliano时代构造-热活动（下寒武统）的结束有关。上第四纪以来，随着碳酸盐岩储层的不断发掘，地表大气富氧水的引入日益有利于浅层含水层的硫化物氧化。硫酸造井（SAS）产生的CO2沿裂缝上升，并在浅层脱气，在靠近地下水位处产生碳酸盐岩造井。这种可能仍然活跃的碳洞穴形成作用，通过从喂食器流出的侵蚀性液体的水平扩散，形成了一个迷宫网络。表面破裂增加了空气流动，激活了盆地的脱气和过饱和，水下方解石架沉积，留下了与仍在进行的黄铁矿氧化（局部SAS）有关的二氧化碳脱气所造成的气泡痕迹。

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