Long-term influence of Miocene intermontane basin alluvial sediments capture in arid valley thalwegs morphometry in the Central Andes (∼29°S)

IF 1.7 4区地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY

Journal of South American Earth Sciences Pub Date : 2025-03-26 DOI:10.1016/j.jsames.2025.105498

Germán Aguilar , Katia Rossel , Albert Cabré , María Pía Rodríguez

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Abstract

Landscape evolution models suggest that thalweg morphometry is influenced by a combination of factors, including the rate of rock uplift, the soil erodibility, the channel geometry, the sediment properties and availability, and the climate changes. Approximately 6 Ma ago, the uppermost catchment of the El Transito river (∼29°S, Central Andes) captured an intermontane basin containing thick alluvial successions dating 19 to 13 Ma. We carried out an analysis of thalweg profiles to explore morphometric changes by this intermontane basin capture. The valleys that captured this basin exhibit flat profiles, with stationary knickpoints located at the basin boundaries. We propose that the supply of alluvial gravels from the intermontane basin shielded the thalweg upstream, reducing incision, while simultaneously providing abrasive material that favored incision downstream. Our findings underscore the importance of considering the long-term influence of sedimentary deposits capture when interpreting the morphometry of arid valleys in the Central Andes.

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安第斯中部（~ 29°S）干旱河谷中中新世山间盆地冲积沉积物捕获的长期影响

景观演化模型表明，地形形态测量受多种因素的影响，包括岩石隆升速率、土壤可蚀性、河道几何形状、沉积物性质和可利用性以及气候变化。大约6 Ma以前，El Transito河的最上层集水区（~ 29°S，安第斯山脉中部）形成了一个山间盆地，其中包含19至13 Ma的厚冲积层。我们进行了thalweg剖面分析，以探索这种山间盆地捕获的形态计量学变化。捕获这个盆地的山谷呈现出平坦的轮廓，在盆地边界有固定的裂缝点。我们认为，来自山间盆地的冲积砾石的供应屏蔽了上游的沙坝，减少了切口，同时提供了有利于下游切口的磨料。我们的研究结果强调了在解释安第斯山脉中部干旱山谷的形态计量学时，考虑沉积沉积物捕获的长期影响的重要性。

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来源期刊

Journal of South American Earth Sciences 地学-地球科学综合

CiteScore

3.70

自引率

22.20%

发文量

364

审稿时长

6-12 weeks

期刊介绍： Papers must have a regional appeal and should present work of more than local significance. Research papers dealing with the regional geology of South American cratons and mobile belts, within the following research fields: -Economic geology, metallogenesis and hydrocarbon genesis and reservoirs. -Geophysics, geochemistry, volcanology, igneous and metamorphic petrology. -Tectonics, neo- and seismotectonics and geodynamic modeling. -Geomorphology, geological hazards, environmental geology, climate change in America and Antarctica, and soil research. -Stratigraphy, sedimentology, structure and basin evolution. -Paleontology, paleoecology, paleoclimatology and Quaternary geology. New developments in already established regional projects and new initiatives dealing with the geology of the continent will be summarized and presented on a regular basis. Short notes, discussions, book reviews and conference and workshop reports will also be included when relevant.