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Vincent Jomelli - One of the best experts on this subject based on the ideXlab platform.

  • incision and aggradation in proglacial rivers post little ice age long profile adjustments of southern iceland Outwash plains
    Land Degradation & Development, 2018
    Co-Authors: Erwan Roussel, Philip M Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    This is the peer reviewed version of the following article: Roussel, R., Marren, P.M., Cossart, E., Toumazet, J-M., Chenet, M., Grancher, D., Jomelli, V. (2018). Incision and aggradation in proglacial rivers: post-Little Ice Age long-profile adjustments of southern Iceland Outwash plains. Land Degradation & Development, 29(10), 3753-3771, which has been published in final form at https://doi.org/10.1002/ldr.3127. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

  • Incision and aggradation in proglacial rivers: Post-Little Ice Age long-profile adjustments of Southern Iceland Outwash plains
    Land Degradation and Development, 2018
    Co-Authors: Erwan Roussel, Philip Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    The retreat of glaciers in response to climate warming leads to substantial changes in meltwater and sediment yield. Glacial shrinkage also induces the emergence and growth of proglacial margin landforms which strongly affect water and sedimentary transfers from the glacier to the Outwash plains. On a decadal-timescale, field observations show that Outwash plains of retreating glaciers typically exhibit proximal incision which decreases in magnitude downstream and stops at an inflection point where aggradation begins. Nevertheless, there is a lack of knowledge about the rates and magnitude of this fluvial adjustment and the effects of the proglacial margin configuration on the temperance or the aggravation of this fluvial adjustment to glacier retreat. This paper investigates the proglacial rivers of 14 retreating glaciers in southeast Iceland over a post-Little Ice Age timescale, combining fluvial deposits mapping, lichenometric dating and long-profile measurements of proglacial fluvial terraces. Our results demonstrate that: (1) proximal incision, associated with distal aggradation and downstream migration of the inflection point is the dominant pattern of proglacial river response to post-LIA glacier retreat in Iceland; (2) estimated mean rates of downstream migration of the inflection point range between 5 and 46 m.a-1 ; (3) the downstream migration rate of the inflection point is positively correlated with the proportion of proglacial lakes within the glacier foreland. These findings suggest that proglacial margins dominated by proglacial lakes intensify the rates of proximal incision and inflection point migration

Erwan Roussel - One of the best experts on this subject based on the ideXlab platform.

  • incision and aggradation in proglacial rivers post little ice age long profile adjustments of southern iceland Outwash plains
    Land Degradation & Development, 2018
    Co-Authors: Erwan Roussel, Philip M Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    This is the peer reviewed version of the following article: Roussel, R., Marren, P.M., Cossart, E., Toumazet, J-M., Chenet, M., Grancher, D., Jomelli, V. (2018). Incision and aggradation in proglacial rivers: post-Little Ice Age long-profile adjustments of southern Iceland Outwash plains. Land Degradation & Development, 29(10), 3753-3771, which has been published in final form at https://doi.org/10.1002/ldr.3127. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

  • Incision and aggradation in proglacial rivers: Post-Little Ice Age long-profile adjustments of Southern Iceland Outwash plains
    Land Degradation and Development, 2018
    Co-Authors: Erwan Roussel, Philip Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    The retreat of glaciers in response to climate warming leads to substantial changes in meltwater and sediment yield. Glacial shrinkage also induces the emergence and growth of proglacial margin landforms which strongly affect water and sedimentary transfers from the glacier to the Outwash plains. On a decadal-timescale, field observations show that Outwash plains of retreating glaciers typically exhibit proximal incision which decreases in magnitude downstream and stops at an inflection point where aggradation begins. Nevertheless, there is a lack of knowledge about the rates and magnitude of this fluvial adjustment and the effects of the proglacial margin configuration on the temperance or the aggravation of this fluvial adjustment to glacier retreat. This paper investigates the proglacial rivers of 14 retreating glaciers in southeast Iceland over a post-Little Ice Age timescale, combining fluvial deposits mapping, lichenometric dating and long-profile measurements of proglacial fluvial terraces. Our results demonstrate that: (1) proximal incision, associated with distal aggradation and downstream migration of the inflection point is the dominant pattern of proglacial river response to post-LIA glacier retreat in Iceland; (2) estimated mean rates of downstream migration of the inflection point range between 5 and 46 m.a-1 ; (3) the downstream migration rate of the inflection point is positively correlated with the proportion of proglacial lakes within the glacier foreland. These findings suggest that proglacial margins dominated by proglacial lakes intensify the rates of proximal incision and inflection point migration

Jasper Knight - One of the best experts on this subject based on the ideXlab platform.

  • significance of soft sediment clasts in glacial Outwash puget sound usa
    Sedimentary Geology, 2009
    Co-Authors: Jasper Knight
    Abstract:

    Abstract Soft-sediment clasts composed of silt and clay are contained within glacial Outwash sands in the Puget Sound, Washington State, USA. The Outwash was deposited during ice retreat of the Cordilleran ice sheet around 17 cal kyr BP. The soft-sediment clasts have a distinctive and consistent morphology and disposition within the sand beds. The sedimentology, sedimentary structures and presence of soft-sediment clasts suggest sand was deposited as proglacial Outwash with silts and clays deposited in meltwater pools. Following drying-out of the pools and subaerial cracking, lumps of silt and clay were excavated by meltwater and transported distally as soft-sediment clasts within high-density flows. The most likely final depositional setting is as a Salisbury-type ‘delta’ in which subaqueous Outwash grades distally into deeper water. This interpretation shows the power of soft-sediment clasts to inform on past processes and palaeogeography for which there is often little evidence in the geologic record.

  • morphology and palaeoenvironmental interpretation of deformed soft sediment clasts examples from within late pleistocene glacial Outwash tempo valley northern ireland
    Sedimentary Geology, 1999
    Co-Authors: Jasper Knight
    Abstract:

    Abstract Glacial Outwash, deposited during deglaciation of the late Devensian ice sheet, is present as a flat-topped valley fill in the Tempo Valley on the southern flanks of the Fintona Hills, Northern Ireland. Sedimentologically, the Outwash comprises well-sorted and interbedded rippled to massive sands which record distal deposition within a proglacial water body. Beds of ripple-drift cross-laminated sands contain deformed (folded and contorted) soft-sediment clasts which are composed mainly of silt and clay. The soft-sediment clasts were deformed prior to final deposition because clast a–b planes lie conformable to sand laminae which are undeformed. Morphological characteristics of the soft-sediment clasts, and their facies context, provide evidence for transport mechanisms, depositional environment, and processes of clast deformation. The soft-sediment clasts were transported into a proglacial water body by unidirectional water currents (∼1.5–2.5 m s−1). Sediment transport processes include sediment bypassing within the water column, a low bedload component, and grain flow activity during waning flow stages. The overall morphology of soft-sediment clasts records between 1 and 3 distinct phases of hydroplastic deformation prior to emplacement. The deformation phases are recognised on the basis of morphologically `unrolling' the superimposed folds of the soft-sediment clasts. Deformation structures (i.e. fold style) and direction of the principal stress axis relative to clast axes suggest that clasts were reoriented with respect to water flow direction following each deformation phase. Processes of deformation include folding-over of the clast along its b axis into two or more components, crumpling and abrasion of the outer margins of the b plane, and squashing of the clast c axis (some of which may be post-depositional deformation). The presence of silt- and clay-rich soft-sediment clasts within the Outwash succession suggests that they were ripped-up from shallow and irregular pools on the glacier forefield, into which fine sediments accumulated after flood or meltwater events, and transported distally into a proglacial water body. These inferences based on facies evidence and styles of hydroplastic deformation impact on reconstructions of local palaeogeography, and the wider interpretation of similar soft-sediment clasts in the geological record.

Delphine Grancher - One of the best experts on this subject based on the ideXlab platform.

  • incision and aggradation in proglacial rivers post little ice age long profile adjustments of southern iceland Outwash plains
    Land Degradation & Development, 2018
    Co-Authors: Erwan Roussel, Philip M Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    This is the peer reviewed version of the following article: Roussel, R., Marren, P.M., Cossart, E., Toumazet, J-M., Chenet, M., Grancher, D., Jomelli, V. (2018). Incision and aggradation in proglacial rivers: post-Little Ice Age long-profile adjustments of southern Iceland Outwash plains. Land Degradation & Development, 29(10), 3753-3771, which has been published in final form at https://doi.org/10.1002/ldr.3127. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

  • Incision and aggradation in proglacial rivers: Post-Little Ice Age long-profile adjustments of Southern Iceland Outwash plains
    Land Degradation and Development, 2018
    Co-Authors: Erwan Roussel, Philip Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    The retreat of glaciers in response to climate warming leads to substantial changes in meltwater and sediment yield. Glacial shrinkage also induces the emergence and growth of proglacial margin landforms which strongly affect water and sedimentary transfers from the glacier to the Outwash plains. On a decadal-timescale, field observations show that Outwash plains of retreating glaciers typically exhibit proximal incision which decreases in magnitude downstream and stops at an inflection point where aggradation begins. Nevertheless, there is a lack of knowledge about the rates and magnitude of this fluvial adjustment and the effects of the proglacial margin configuration on the temperance or the aggravation of this fluvial adjustment to glacier retreat. This paper investigates the proglacial rivers of 14 retreating glaciers in southeast Iceland over a post-Little Ice Age timescale, combining fluvial deposits mapping, lichenometric dating and long-profile measurements of proglacial fluvial terraces. Our results demonstrate that: (1) proximal incision, associated with distal aggradation and downstream migration of the inflection point is the dominant pattern of proglacial river response to post-LIA glacier retreat in Iceland; (2) estimated mean rates of downstream migration of the inflection point range between 5 and 46 m.a-1 ; (3) the downstream migration rate of the inflection point is positively correlated with the proportion of proglacial lakes within the glacier foreland. These findings suggest that proglacial margins dominated by proglacial lakes intensify the rates of proximal incision and inflection point migration

Marie Chenet - One of the best experts on this subject based on the ideXlab platform.

  • incision and aggradation in proglacial rivers post little ice age long profile adjustments of southern iceland Outwash plains
    Land Degradation & Development, 2018
    Co-Authors: Erwan Roussel, Philip M Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    This is the peer reviewed version of the following article: Roussel, R., Marren, P.M., Cossart, E., Toumazet, J-M., Chenet, M., Grancher, D., Jomelli, V. (2018). Incision and aggradation in proglacial rivers: post-Little Ice Age long-profile adjustments of southern Iceland Outwash plains. Land Degradation & Development, 29(10), 3753-3771, which has been published in final form at https://doi.org/10.1002/ldr.3127. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

  • Incision and aggradation in proglacial rivers: Post-Little Ice Age long-profile adjustments of Southern Iceland Outwash plains
    Land Degradation and Development, 2018
    Co-Authors: Erwan Roussel, Philip Marren, Etienne Cossart, Jean-pierre Toumazet, Marie Chenet, Delphine Grancher, Vincent Jomelli
    Abstract:

    The retreat of glaciers in response to climate warming leads to substantial changes in meltwater and sediment yield. Glacial shrinkage also induces the emergence and growth of proglacial margin landforms which strongly affect water and sedimentary transfers from the glacier to the Outwash plains. On a decadal-timescale, field observations show that Outwash plains of retreating glaciers typically exhibit proximal incision which decreases in magnitude downstream and stops at an inflection point where aggradation begins. Nevertheless, there is a lack of knowledge about the rates and magnitude of this fluvial adjustment and the effects of the proglacial margin configuration on the temperance or the aggravation of this fluvial adjustment to glacier retreat. This paper investigates the proglacial rivers of 14 retreating glaciers in southeast Iceland over a post-Little Ice Age timescale, combining fluvial deposits mapping, lichenometric dating and long-profile measurements of proglacial fluvial terraces. Our results demonstrate that: (1) proximal incision, associated with distal aggradation and downstream migration of the inflection point is the dominant pattern of proglacial river response to post-LIA glacier retreat in Iceland; (2) estimated mean rates of downstream migration of the inflection point range between 5 and 46 m.a-1 ; (3) the downstream migration rate of the inflection point is positively correlated with the proportion of proglacial lakes within the glacier foreland. These findings suggest that proglacial margins dominated by proglacial lakes intensify the rates of proximal incision and inflection point migration