Postorogenic planar palaeosurfaces of the central Pyrenees: Weathering and neotectonic records

Monod, Bernard; Regard, Vincent; Carcone, Julie; Wyns, Robert; Christophoul, Frédéric

doi:10.1016/j.crte.2015.09.005

Cited by 19 publications

(16 citation statements)

References 31 publications

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“…To minimize this impact we have compared the δ 18 O of rodent teeth of two sites, one that remained at low elevation and one that was potentially uplifted. We derive a paleo-∆δ 18 O w that could be converted to ∆-elevation 23 . Geochemical results are provided in Supplementary Dataset 1.…”

Section: Methodsmentioning

confidence: 99%

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Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

Huyghe

Mouthereau

Ségalen

et al. 2020

Sci Rep

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Understanding the geodynamic and earth surface processes at the origin of post-collisional surface uplift in mountain ranges requires reconstruction of paleo-elevation. Here, we focus on the topographic evolution of the cerdanya Basin in the eastern pyrenees formed by post-orogenic extension during the Late Miocene. Stable isotope (δ 18 o) analyses of small rodent teeth and biogenic carbonates show the basin uplifted by 500 m since 6.5 Ma. These new paleoaltitudes constraints when combined with the regional geology and geophysical data reveal the anomalously high topography of the region is the result of density changes in the sublithospheric mantle associated with crustal thinning and then opening of Gulf of Lion during the chattian-early Burdigalian.

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Section: Methodsmentioning

confidence: 99%

“…The central and eastern Pyrenees are further characterized by the presence of late Oligocene-early Miocene highly-elevated low relief surfaces, considered remnants of a single composite planation surface recently dissected 18 . There is a great debate about how these surfaces were created and especially at which elevation.…”

mentioning

confidence: 99%

Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

Huyghe

Mouthereau

Ségalen

et al. 2020

Sci Rep

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“…The main geomorphological features of the area are relict remains of Neogene planation surfaces [30,31] (and references therein), small glacial cirques in the highest areas, and active fluvio-torrential and slope processes affecting the whole territory ( Figure 1). The residual planation surfaces correspond to smooth mountain ridges with gentle slopes (<15 • ), like the one extending around the flat top of Torreta de l'Orri [28].…”

Section: Evolution Of the Area And Present Featuresmentioning

confidence: 99%

“…The residual planation surfaces correspond to smooth mountain ridges with gentle slopes (<15 • ), like the one extending around the flat top of Torreta de l'Orri [28]. The incision of the main Pyrenean rivers dissecting these surfaces rejuvenated the relief [30]. On a more local scale, the Romadriu river and its tributaries, like those of the Portainé basin, originated high reliefs (500-1000 m) with narrow valleys and steep slopes (see Section 1.2).…”

Section: Evolution Of the Area And Present Featuresmentioning

confidence: 99%

Flood Consequences of Land-Use Changes at a Ski Resort: Overcoming a Geomorphological Threshold (Portainé, Eastern Pyrenees, Iberian Peninsula)

Furdada

Victoriano

Díez‐Herrero

et al. 2020

Water

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The sensitive mountain catchment of Portainé (Eastern Pyrenees, Iberian Peninsula) has recently experienced a significant change in its torrential dynamics due to human disturbances. The emplacement of a ski resort at the headwaters led to the surpassing of a geomorphological threshold, with important consequences during flood events. Consequently, since 2008, channel dynamics have turned into sediment-laden, highly destructive torrential flows. In order to assess this phenomenon and o acquire a holistic understanding of the catchment’s behaviour, we carried out a field work-based multidisciplinary study. We considered the interaction of the various controlling factors, including bedrock geology, geomorphological evolution, derived soils and coluvial deposits, rainfall patterns, and the hydrological response of the catchment to flood events. Moreover, anthropogenic land-use changes, its consequential hydrogeomorphic effects and the role of vegetation were also taken into account. Robust sedimentological and geomorphological evidence of ancient dense debris flows show that the basin has shifted around this threshold, giving rise to two different behaviours or equilibrium conditions throughout its history: alternating periods of moderate, bedload-laden flows and periods of high sediment-laden debris flow dynamics. This shifting could have extended through the Holocene. Finally, we discuss the possible impact of climate and global change, as the projected effects suggest future soil and forest degradation; this, jointly with more intense rainfalls in these mountain environments, would exacerbate the future occurrence of dense sediment-laden flows at Portainé, but also in other nearby, similar basins.

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“…the weathering regime, has been in favour of deepening the regolith through chemical weathering (towards kinetically limited regime), rather than by erosive stripping (e.g. Migoń and Lidmar‐Bergström, ; de Oliveira Carmo and Vasconcelos, ; Chadwick et al , ; von Blanckenburg et al , ; Monod et al , in Press). In addition, successive periods of laterization (usually leading to the formation of thick regolith and different generations of iron crust) have resulted from climate changes (Tardy and Roquin, ; Retallack, ).…”

Section: Introductionmentioning

confidence: 99%

Denudation rates on cratonic landscapes: comparison between suspended and dissolved fluxes, and ¹⁰Be analysis in the Nyong and Sanaga River basins, south Cameroon

Regard

Carretier

Boeglin

et al. 2016

Earth Surf Processes Landf

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South Cameroon is located in a tropical and tectonically quiescent region, with landscapes characterized by thick highly weathered regolith, indicative of the long-term predominance of chemical weathering over erosion. Currently this region undergoes huge changes due to accelerated mutations related to a growing population and economical developments with associated needs and increasing pressures on land and natural resources. We analysed two of the main south Cameroon rivers: the Nyong River and Sanaga River. The Sanaga catchment undergoes a contrasted tropical climate from sub-humid mountainous and humid climate and is impacted by deforestation, agriculture, damming, mining and urbanization, especially in the Mbam sub-basin, draining the highly populated volcanic highlands. By contrast, the Nyong catchment, only under humid tropical climate, is preserved from anthropogenic disturbance with low population except in the region of Yaoundé (Méfou sub-basin). Moreover the Nyong basin is dam-free and less impacted by agriculture and logging.We explore both denudation temporal variability and the ratio between chemical and physical denudation through two catchmentaveraged erosion and denudation datasets. The first one consists of an 11-year long gauging dataset, while the second one comes from cosmogenic radionuclides [CRNs, here beryllium-10 ( 10 Be)] from sand sampled in the river mainstreams (timescale of tens to hundreds of thousands of years). Modern fluxes estimated from gauging data range from 5 to 100 m/Ma (10 to 200 t/km 2 /yr); our calculations indicate that the usual relative contribution of chemical versus physical denudation is 60% and 40%, respectively, of the total denudation. Beryllium-10 denudation rates and sediment fluxes range from 4.8 to 40.3 m/Ma or 13 to 109 t/km 2 /yr, respectively, after correction for quartz enrichment. These fluxes are slightly less than the modern fluxes observed in Cameroon and other stable tropical areas. The highest 10 Be-derived fluxes and the highest physical versus chemical denudation ratios are attributed to anthropogenic impact.

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Postorogenic planar palaeosurfaces of the central Pyrenees: Weathering and neotectonic records

Cited by 19 publications

References 31 publications

Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

Flood Consequences of Land-Use Changes at a Ski Resort: Overcoming a Geomorphological Threshold (Portainé, Eastern Pyrenees, Iberian Peninsula)

Denudation rates on cratonic landscapes: comparison between suspended and dissolved fluxes, and ¹⁰Be analysis in the Nyong and Sanaga River basins, south Cameroon

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Postorogenic planar palaeosurfaces of the central Pyrenees: Weathering and neotectonic records

Cited by 19 publications

References 31 publications

Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

Long-term dynamic topographic support during post-orogenic crustal thinning revealed by stable isotope (δ18O) paleo-altimetry in eastern Pyrenees

Flood Consequences of Land-Use Changes at a Ski Resort: Overcoming a Geomorphological Threshold (Portainé, Eastern Pyrenees, Iberian Peninsula)

Denudation rates on cratonic landscapes: comparison between suspended and dissolved fluxes, and 10Be analysis in the Nyong and Sanaga River basins, south Cameroon

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Denudation rates on cratonic landscapes: comparison between suspended and dissolved fluxes, and ¹⁰Be analysis in the Nyong and Sanaga River basins, south Cameroon