Quaternary evolution of the Golo river alluvial plain (NE Corsica, France)
Introduction
Coastal alluvial plains are key places for understanding sediment storage in a source-to-sink approach (e.g. Sømme et al., 2011; Blum et al., 2013). However, the consequences of aggradation/degradation cycles in coastal plains due to Quaternary sea-level oscillations make stratigraphic correlations difficult, with upstream (alluvial terraces) or downstream (shelf sediment accumulation) deposits. Since a decade, alluvial plains focused new research efforts, thanks to the development of relevant tools, such as dating methods on fluvial sequences. Moreover, these settings record paleo-environmental parameters controlling sediment fluxes, such as tectonics, climate or sea-level fluctuations (e.g. Twidale, 2004; Allen, 2008). In many cases, the extent of alluvial depositional terraces in alluvial plains is mainly based on topographic constraints, such as breaks in slope and escarpments (e.g. Conchon, 1975). Mapping the accurate lateral extension of alluvial terraces and determining their in-depth geometry remain often problematic and suffer from large uncertainties. Notably, the relevant resolution of topographic data is not always available and geophysical surveys are sometimes difficult to conduct in anthropogenic areas.
The geochemical maturity of an alluvial soil increases with age: while Holocene deposits are not weathered, soils from Pleistocene alluvial deposits of Mediterranean periglacial areas are matured, rich in clay, and may become reddish after experiencing several warm phases of Quaternary climatic cycles (e.g. Baize and Girard, 2008; Legros, 2012). Studying chronology of soil sequences on alluvial terraces in addition to geomorphic analysis is thus a very efficient way to determine relative chronology of deposits (Hubschman, 1973; Bornand, 1978; Delmas et al., 2015). Moreover, the use of terrestrial cosmogenic nuclides has proven its efficiency for absolute dating of alluvial deposits (e.g. Granger et al., 1996; Hancock et al., 1999; Brocard et al., 2003; Siame et al., 2004; Molliex et al., 2013).
The high and steep topography of Corsica leads to a strong sensitivity of sediment transfers due to regional climate changes, even for moderate variations (Kuhlemann et al., 2008a). The Golo River system (Eastern Corsica) is considered as a reactive system (Allen, 2008), characterized by a fast sediment transfer from the catchment to the sink (Sømme et al., 2011; Calves et al., 2013; Forzoni et al., 2015), and rapidly reacts to climate changes. Sediment volumes deposited in the alluvial plain and the deep-sea fan during the Holocene are compatible with sedimentary fluxes inferred from cosmogenic denudation rates in the catchment (Sømme et al., 2011; Calves et al., 2013; Molliex et al., 2017). However, some studies suggest that alluvial terraces in the plain may be diachronous and that the Golo River may have deposited sediment by aggradation along its entire profile at any time during the late Quaternary. Such climatically-driven pulses in sediment supply may hamper detailed stratigraphic correlations (Conchon, 1978; Sømme et al., 2011; Forzoni et al., 2015). The chronology of the Golo alluvial terraces was first established from relative dating: Conchon (1975, 1977) associated each terrace to a full glacial cycle. Later, luminescence methods applied on sand lenses of outcropping terraces (OSL on quartz and IRSL on feldspar) suggested younger ages for Fy1, Fy2, Fy3 terraces, in correlation with smaller climatic oscillations (Sømme et al., 2011; Skyles, 2013; Forzoni et al., 2015) (Table 1). Moreover, luminescence dating yields ages of terrace aggradation that are not always internally consistent, and do not always correspond to climatic oscillations and full glacial stages. Sediment buffering in the alluvial and coastal plain may play an important role in the transfer from the source to the sink and may alter a simple relationship between climate and deposition in the alluvial plain (Sømme et al., 2011; Calves et al., 2013). Obtain new absolute ages from the sedimentary material of the Golo alluvial plain is thus key to progress on understanding these processes.
In this paper, we present an updated geological model of the Golo alluvial plain based on new data acquired both in surface (geomorphology, pedology) and depth (borehole, Electrical Resistivity Tomography). We also revised the chronology of formations using new cosmogenic nuclides data (10Be depth profile and 26Al/10Be burial ages). Finally, we discuss the Quaternary evolution of the Golo coastal alluvial plain in response to Quaternary climate and tectonic forcings.
Section snippets
Geological setting
Corsica is an island of 8722 km2 located in the northern part of the western Mediterranean, in the Ligurian Sea. It is characterized by a steep mountainous morphology, with elevations reaching more than 2700 m (Fig. 1A).
With a catchment area of 1214 km2 and a length of 89 km, the Golo is the largest river in Corsica (Fig. 1A). Originating from 1991 m, the Golo flows mainly eastward up to the Ligurian Sea with an average gradient of 30 m km−1 (Fig. 1A). There are almost no preserved alluvial
Geomorphology
Since the resolution of available Digital Elevation Model (DEM) in the Golo alluvial plain was not sufficient, we compiled a DEM from the digitized 1/25,000-scale topographic map from the French Geographic institute (IGN), complemented by a microtopographic differential GPS survey in areas of interest (e.g. alluvial terraces boundaries, local depression or bulges). From this DEM, we compute gradient slope map and we extracted the theoretical hydrologic network using ArcGis software®. In
Geomorphology
The alluvial plain is a fairly flat eastward dipping surface characterized by a mean elevation of 36 m asl (above sea level) and reaching locally 127 m asl (Fig. 2). The elevation rapidly decreases eastward (from 127 m asl to 15 m asl; brown to yellow in Fig. 2) from the Alpine foothills to the middle of the plain and then moderately decreases from the middle of the plain to the shoreline (from 15 to 0 m asl; yellow to green in Fig. 2). Three geomorphological domains in the Golo alluvial plain
Chronology of Late Pleistocene events
Aggradation of sediment in alluvial systems depends of slope, base level and sediment transport rate (e.g. Blum and Törnqvist, 2000). In a coastal alluvial plain such as the Golo, fluvial aggradation is strongly controlled by sea-level fluctuations. Fluvial aggradation generally occurs during sea-level highstands, i.e. deglacial (valley filling) and interglacial (upstream overflow) stages (e.g. Blum and Törnqvist, 2000), because fluvial slope may decrease, as well as the transport capacity of
Conclusion
For a better understanding of the Quaternary evolution of the Golo River alluvial plain, we obtained data from several approaches, including geomorphology, soil studies, sedimentology, ERT profile and terrestrial cosmogenic nuclides dating (10Be and 26Al). We improved the accuracy and resolution of geological mapping of Quaternary alluvial sheets in the Golo plain and provided new chronological constrains based on soil chronosequence and cosmogenic nuclides. We highlighted at least four
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This research was financed by IFREMER, the “Agence de l’Eau Rhône-Méditerranée-Corse” and also benefited from a State Grant from the French “ Agence Nationale de la Recherche (ANR)" in the Program “Investissements d'Avenir” (ANR-10-LABX-19-01, Labex Mer). It was finalized as part of the EROMED ANR program (ANR-17-CE01-0011). JEAS was funded by ALW-NWO (Dutch Organization for Scientific Research, VIDI grant number 864.09.004). We warmly thank Daniel Hermitte, Jean-Claude Parisot, Phillipe
References (113)
- et al.
The French accelerator mass spectrometry facility ASTER: improved performance and developments
Nucl. Instrum. Methods Phys. Res. Sect. B Beam Interact. Mater. Atoms
(2010) - et al.
Measurement of anomalous fading for feldspar IRSL using SAR
Radiat. Meas.
(2003) - et al.
Luminescence investigation of loess and tephra from Halfway House section, Central Alaska
Quat. Geochronol.
(2007) - et al.
A complete and easily accessible means of calculating surface exposure ages or erosion rates from 10Be and 26Al measurements
Quat. Geochronol.
(2008) - et al.
Paired-cosmogenic nuclide paleoaltimetry
Earth Planet Sci. Lett.
(2019) - et al.
Two MATLAB programs for computing paleo-elevations and burial ages from paired-cosmogenic nuclides
Methods (Orlando)
(2019) - et al.
Paleovalley systems: insights from Quaternary analogs and experiments
Earth Sci. Rev.
(2013) - et al.
The Pliocene and Quaternary fluvial archives of the Rhine system
Quat. Sci. Rev.
(2006) - et al.
Determination of both exposure time and denudation rate from an in situ-produced Be-10 depth profile: a mathematical proof of uniqueness. Model sensitivity and applications to natural cases
Quat. Geochronol.
(2009) - et al.
Production of cosmogenic radionuclides at great depth: a multi element approach
Earth Planet Sci. Lett.
(2011)
Long-term fluvial incision rates and postglacial river relaxation time in the French Western Alps from 10Be dating of alluvial terraces with assessment of inheritance, soil development and wind ablation effects
Earth Planet Sci. Lett.
Luminescence dating of old (> 70 ka) Chinese loess: a comparison of single-aliquot OSL and IRSL techniques
Quat. Geochronol.
Testing post-IR IRSL luminescence dating methods in the southwest Mojave Desert, California, USA
Quat. Geochronol.
Quaternary studies in Corsica (France)
Quat. Res.
Quaternary glaciations in Corsica
Quat. Sci. Rev.
Constraints on Pleistocene glaciofluvial terrace age and related soil chronosequence features from vertical 10Be profiles in the Ariège River catchment (Pyrenees, France)
Global Planet. Change
Terrestrial10Be and electron spin resonance dating of fluvial terraces quantifies quaternary tectonic uplift gradients in the eastern Pyrenees
Quat. Sci. Rev.
Luminescence dating using feldspars: a test case from southern North Island, New Zealand
Quat. Sci. Rev.
Pedogenic carbonates on Precambrian metamorphic rocks in South India: origin and paleoclimatic significance
Quat. Int.
The equivalent dose of different grain size quartz fractions from lakeshore sediments in the arid region of north China
Quat. Geochronol.
The thermal evolution of Corsica as recorded by zircon fission-tracks
Tectonophysics
Non-linear response of the Golo River system, Corsica, France, to Late Quaternary climatic and sea level variations
Quat. Sci. Rev.
Terrestrial in situ cosmogenic nuclides: theory and application
Quat. Sci. Rev.
Contribution of geophysics to the study of alluvial deposits: a case study in the Val d'Avaray area of the River Loire, France
J. Appl. Geophys.
Dating fluvial terraces with 10Be and 26Al profiles: application to the wind river, Wyoming
Geomorphology
Progressive and polyphase deformation of the schistes lustres in cap corse, alpine Corsica
J. Struct. Geol.
The effect of weathering on optically stimulated luminescence dating
Quat. Geochronol.
A new approach towards anomalous fading correction for feldspar IRSL dating—tests on samples in field saturation
Radiat. Meas.
Validating post IR-IRSL dating on K-feldspars through comparison with quartz OSL ages
Quat. Geochronol.
Interpreting scattered in-situ produced cosmogenic nuclide depth-profile data
Quat. Geochronol.
Luminescence dating of K-feldspar from sediments: a protocol without anomalous fading correction
Quat. Geochronol.
Investigating age underestimation in the high dose region of optically stimulated luminescence using fine grain quartz
Quat. Geochronol.
Characterising the luminescence behaviour of ‘infinitely old’quartz samples from Switzerland
Quat. Geochronol.
The Burdigalian of eastern Corsica within its geodynamic setting
Compt. Rendus Geosci.
The CREp program and the ICE-D production rate calibration database: a fully parameterizable and updated online tool to compute cosmic-ray exposure ages
Quat. Geochronol.
Transverse lineation and large-scale structures related to alpine obduction in Corsica
J. Struct. Geol.
Towards more precise 10Be and 36Cl data from measurements at the 10-14 level: influence of sample preparation
Nucl. Instrum. Methods Phys. Res. B
Environmental processes of the ice age: land, oceans, glaciers (EPILOG)
Quat. Sci. Rev.
Quaternary evolution of a large alluvial fan in a peri-glacial setting (Crau plain, SE France), constrained by terrestrial cosmogenic nuclide (10Be)
Geomorphology
Geomagnetic field intensity during the last 60,000 years based on10Be and36Cl from the Summit ice cores and14C
Quat. Sci. Rev.
Preparation of 26Al AMS standards
Nucl. Instrum. Methods Phys. Res. Sect. B Beam Interact. Mater. Atoms
Absolute calibration of 10Be AMS standards
Nucl. Instrum. Methods Phys. Res. Sect. B Beam Interact. Mater. Atoms
Relative sea-level fall since the last interglacial stage: are coasts uplifting worldwide?
Earth Sci. Rev.
Climatic reconstruction in Europe for 18,000 yr B.P. from pollen data
Quat. Res.
Getting a grip on soil reworking–Single-grain feldspar luminescence as a novel tool to quantify soil reworking rates
Quat. Geochronol.
Review and new aspects concerning the formation of eastern Mediterranean sapropels
Mar. Geol.
Mediterranean climate and oceanography, and the periodic development of anoxic events (sapropels)
Earth Sci. Rev.
Major temporal variations in shortening rate absorbed along a large active fold of the southeastern Tianshan piedmont (China)
Earth Planet Sci. Lett.
Local erosion rates versus active tectonics: cosmic ray exposure modelling in Provence (south-east France)
Earth Planet Sci. Lett.
Time scales of tectonic landsapes and their sediment routing systems
Cited by (0)
- 1
Georges Aumaître, Didier L. Bourlès, Karim Keddadouche.