Tectonic controls on the morphometry of alluvial fans around Danehkhoshk anticline, Zagros, Iran

Bahrami, Shahram

doi:10.1016/j.geomorph.2012.10.012

Cited by 50 publications

(18 citation statements)

References 63 publications

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“…26 morphological development of alluvial fans associated with actively growing fold structures has been considered by Bahrami (2013). However, in terms of this study the structural control is considered to be tectonically passive where the fold structure simply provides catchment gradients (syn-dip vs. anti-dip) that enhance or limit catchment morphological characteristics and sediment supply.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Controls on modern tributary-junction alluvial fan occurrence and morphology: High Atlas Mountains, Morocco

Stokes

Mather

2015

Geomorphology

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Modern tributary-junction alluvial fans (cone-shaped depositional landforms formed in confined valley settings) were analysed from a 20-km-long reach of the Dades River in the distal part of the fold-thrust belt region in the south-central High Atlas Mountains of Morocco. Here, a deeply dissected network of ephemeral tributary streams and a perennial trunk drainage characterised by an arid mountain desert climate are configured onto a folded and thrust faulted Mesozoic sedimentary sequence. Out of 186 tributary streams, only 29 (16%) generated alluvial fans at their tributary junctions. The fan-generating catchments possess higher relief, longer lengths, lower gradients, and larger areas than nonfan-generating catchments. Whilst geologically, fan-generating catchments are underlain by folded / steeply dipping weak bedrock conducive to high sediment yield. Tributary-junction fans are built from debris flow or fluvial processes into open or confined canyon trunk valley settings. The proximity of the perennial trunk drainage combined with the valley morphology produces lobate or foreshortened trimmed fan forms. Analysis of fan (area, gradient, process), catchment (area, relief, length, gradient), and tributary valley (width) variables reveals weak morphometric relationships, highlighted by A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 2 residual plots that show dominance of smaller and lower gradient than expected fan forms. These morphometric relationships can be explained by interplay between the catchment and trunk drainage geology, morphology, climate, and flood regime that are combined into a conceptual 'build and reset' model. Ephemeral tributary-junction fans develop progressively during annual localised winter-spring storm events, attempting to build toward a morphological equilibrium. However, the fans never reach an equilibrium morphological form as they are reset by rare (>10 year) large floods along the River Dades that are linked to regional incursions of Atlantic low pressure troughs. The model highlights the spatial and temporal variability of tributary-junction fan building and illustrates the connectivity / coupling importance of such features in dryland mountainous terrains.

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Section: Accepted Manuscriptmentioning

confidence: 99%

Controls on modern tributary-junction alluvial fan occurrence and morphology: High Atlas Mountains, Morocco

Stokes

Mather

2015

Geomorphology

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“…As a matter of fact, the FIGURE 7 Source area lithology (based on Karunakaran & Ranga Rao, 1979;Valdiya, 1980), and transverse and longitudinal profiles of the (a), Nandhaur Fan, and (b) Kalaunia Fan [Colour figure can be viewed at wileyonlinelibrary.com] alluvial fan development depends upon two main factors, (a) the characters of the accommodation space in the basin and, (b) sediment supply from the catchment (Goswami, 2016). Sediment supply from the source to sink largely depends upon the tectonics, climate, base level, lithology, geomorphology, and morphometry of the drainage basin (Bull, 1962;Hook, 1968;Calvache, Viseras, & Ferńandez, 1997;Harvey, 2002;Harvey et al, 2005;Blair & McPherson, 2009;Shukla, 2009;Goswami et al, 2009;Arzani, 2012;Bahrami, 2013;Goswami, 2016; and references therein). The characters of the accommodation space on the other hand are closely related to the tectonic activities along the basin-margin and/or in the basin, climate-induced variations in sediment and water influx into the basin and base-level fluctuations (Bahrami, 2013;Clarke, 2015;Goswami et al, 2009;Viseras, Calvache, Soria, & Fernández, 2003;Weissman, Bennett, & Lansdale, 2005;Weissman, Mount, & Fogg, 2002).…”

Section: Discussionmentioning

confidence: 99%

Controls of basin margin tectonics on the morphology of alluvial fans in the western Ganga foreland basin's piedmont zone, India

Goswami

2017

Geological Journal

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Six distinct alluvial fans have developed in the western Ganga basin's piedmont zone between the Ganga (aka Ganges) River in the west and the Sarda River in the east. The basin margin is demarked by the active Himalayan Frontal Thrust along which the Siwalik ranges are uplifted and placed over the alluvia of the Ganga basin. The 6 alluvial fans show marked morphological variances, but their morphometric parameters exhibit proportionality relationships with the “mountain‐front sinuosity index (Smf),” “stream‐gradient index (SL),” and “valley‐floor width to height ratio (Vf)” of the adjoining mountain‐front segments. Correlation and regression analyses reveal that these relationships are statistically significant. The size of the fan is directly proportional to the magnitude of Smf and inversely proportional to the magnitude of SL, whereas the fan gradient is inversely proportional to Smf. The higher the Smf and the lower the SL values, the larger and gentler is the alluvial fan. Given that the studied alluvial fans have developed in the same climatic zone and their drainage basins have similar physiographic, geologic, and climatic conditions, the morphological diversities among the alluvial fans are attributed to the tectonics of the basin margin. Moreover, statistical analyses further rule out any significant relationships of the fan size with area, or drainage density of the drainage basin. The lower values of Smf and Vf and higher values of SL indicate a more active nature and, thus, greater/faster uplift of the mountain‐front and expected deepening of the accommodation space in the adjoining basin, which favoured vertical aggradation and development of smaller and steeper alluvial fans. Conversely, the higher values of Smf and Vf and lower values of SL indicate a less active nature and, thus, relatively lower/slower uplift of the mountain‐front and thus creation of shallower accommodation space in the adjoining basin, favouring the development of larger and gentler alluvial fans.

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“…Page 7 of 30 76 density (D) to assess the erosion risk assessment (Ciccacci et al 1980;Tokunaga 2000;Della Seta et al 2007;Gioia et al 2011;Bahrami 2013). Hierarchical anomaly number estimated to getting a minimum number of each stream order is based on Eq.…”

Section: Denudation Rate Measurementmentioning

confidence: 99%

Multi-criteria-based sub-basin prioritization and its risk assessment of erosion susceptibility in Kansai–Kumari catchment area, India

2019

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Environmental processes are interrupted by the water action like soil erosion, mass movement as well as siltation on the dam in the undulating catchment area. Soil erosion is one of them and degraded the basin potentiality. This paper demonstrates that erosion susceptibility status in the 13 sub-basins of Kansai-Kumari catchment area has been determined depending upon its morphometric, lithology, geomorphic, land use/land cover (LULC), slope and soil characteristics used by integrated micro-watershed prioritization rank which is based on susceptible capacity under geographical information system platform. Risk assessment of soil erosion was measured by hypsometric characteristic (Hi) and denudation rate (tu) to assess the geological stage of landform and risk status for conservative practices. The result shows that SB13, 2 have a high risk (tu > 90 t/km 2 /year) due to the presence of low priority rank of morphometric, geomorphic, slope, soil and high priority rank of lithological set-up and LULC but reached under the late mature geological stage (Hi > 0.35). SB3, 4, 10 have a low risk (tu < 83 t/km 2 /year) due to the presence of high priority rank of morphometric, geology, geomorphic, slope and soil types under the mature stage of geological setting (Hi > 0.5). But SB7, 8, 9 have the medium risk (tu < 85 t/km 2 /year) due to the presence of erosion-prone LULC patterns like cropland and laterite cover but having low final priority rank and old geological stage (Hi < 0.35). Therefore, erosion susceptibility does not depend on morphometric aspects but also depends on other determinant themes at the sub-basin level.

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Tectonic controls on the morphometry of alluvial fans around Danehkhoshk anticline, Zagros, Iran

Cited by 50 publications

References 63 publications

Controls on modern tributary-junction alluvial fan occurrence and morphology: High Atlas Mountains, Morocco

Controls on modern tributary-junction alluvial fan occurrence and morphology: High Atlas Mountains, Morocco

Controls of basin margin tectonics on the morphology of alluvial fans in the western Ganga foreland basin's piedmont zone, India

Multi-criteria-based sub-basin prioritization and its risk assessment of erosion susceptibility in Kansai–Kumari catchment area, India

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