Isabelle Cojan

Isabelle Cojan
MINES ParisTech | ParisTech · Centre de Géosciences (GEOSCIENCES)

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153
Publications
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892
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Publications

Publications (153)
Article
Full-text available
Assessing the contribution of geomorphic processes to the (non‐)preservation of sedimentary deposits is necessary to account for potential bias in measured accumulation rates in the stratigraphic record. In this study, a series of numerical simulations of fluvial meandering successions is performed using FLUMY, a model of channel motions and sedime...
Article
The stratigraphic distribution of paleosols provides a framework to investigate the controls on distal alluvial fan architecture. This study focused on paleosol-bound alluvial cycles (PACs) from the southern Digne-Valensole foreland Basin (SE France, early Miocene). We investigated the duration of the paleosol formation and identified the controlli...
Article
In this study, two new climofunctions based on major elements are proposed from the study of 28 modern alluvial soils with pedogenic carbonate from NE Spain. The first climofunction relates a base ratio (CaO, K2O) to the mean annual temperature (MAT), and the second one the clayeness ratio (Al2O3/SiO2) to the mean annual precipitation (MAP). In bot...
Article
Full-text available
Although abandoned channels are common and identifiable features in alluvial plains, their detailed internal architecture remains overlooked, particularly their coarse permeable compartment, with implications for underground water flow. The actively shifting, gravel‐bed, Ain River (France) provides an opportunity to study the geometry and architect...
Article
The most important raw materials for the building industry are natural quarried rocks. Preservation of this non-renewable resource needs valorizing products, the vast majority of which is currently considered as waste. Among these, dredged sediments have gained much attention and should play a key role in non-renewable natural resource preservation...
Article
Full-text available
The nature of abandoned channels' sedimentary fills has a significant influence on the development and evolution of floodplains and ultimately on fluvial reservoir geometry. A control of bifurcation geometry (i.e., bifurcation angle) on channel abandonment dynamics and resulting channel fills, such as sand plugs, has been intuited many times but ne...
Article
Proposing a quantitative description of fracture main orientations is of prime interest for reservoir modeling. Manual sorting of fracture sets is time consuming and requires individual expertise. Semi automated methods for determination of the number of fracture sets are not developed in structural geology despite complex fracture networks being c...
Article
Understanding submarine sediment conduits is a challenging yet rewarding task given its applications in offshore industries and source-to-sink studies. Despite flow structure dissimilarities, sinuous submarine sediment conduits display morphologies similar to alluvial meandering rivers. An extensive quantification of degrees of (dis)similarity is h...
Preprint
Full-text available
Abstract. The nature of abandoned channels sedimentary fills has a significant influence on the development and evolution of floodplains and ultimately on fluvial reservoir geometry. A control of bifurcation geometry (i.e., bifurcation angle) on channel abandonment dynamics and resulting channel fills, such as sandplug, has been intuited many times...
Article
The issue of identifying stratigraphic units within a sedimentary succession is of prime importance for reservoir studies, because it allows splitting the reservoir into several units with specific parameters, thus reducing the vertical nonstationarity in simulations. A new method is proposed for semi-automatic determination of the sedimentary unit...
Article
This study focuses on the contrasted architectural elements of the two late Pleistocene alluvial fill sequences (T1 and T2 attributed to the Late Saalian and Weichselian) of the upstream Seine River alluvial plain, la Bassée, and constitutes the first estimation of the sediment volumes associated to these glacial cycles along this river. Estimation...
Poster
Channelized turbidite systems are among the most important hydrocarbon reservoirs. Yet building realistic turbidite reservoir models is still a challenge. Flumy has been firstly developed to simulate the long-term evolution of aggrading meandering fluvial systems in order to build facies reservoir models. In this study, Flumy has been transposed to...
Article
On the southern margin of the Tethys, Early Cretaceous sediments cover most of the Central Tunisia. As a result of a Middle Cretaceous sub-aerial exposure, the Late Barremian -Early Albian interval is mainly characterized by a major stratigraphic gap (hiatus). However in the Sidi Bouzid area a continental succession has been deposited called “Kebar...
Article
This study aims to evaluate the potential of magnetic methods to determine the composition of the sediment load in a cross section of an unmanaged meander in the upstream stretch of the Seine River (Marnay-sur-Seine). Suspended particulate matter (SPM) was collected based on a regular sampling scheme along a cross section of the river, at two diffe...
Article
Full-text available
A thermokarst is a collapse feature resulting from the thawing of ice-rich permafrost or of massive ice of various origins. Little attention has been paid to the sedimentary fabric resulting from this type of collapse, except for glaciotectonic features. In western Europe, two palaeo-forms are commonly studied: lithalsas and ice-wedge casts. Collap...
Poster
Full-text available
Characterizing surface dynamics at the input of deltas is key for understanding the behavior of rivers as well as the large scale partitioning of their sediments which has implications on stratigraphic architectures and delta-surface evolution. Indeed, the ability of a river system to either efficiently migrate laterally or to persist at a single l...
Conference Paper
Origine des déformations superficielles observées en Champagne (Aube et Marne) Frédéric Ego?1, Jacques Brulhet1, Philippe Combes2, Cédric Duvail2, Brigitte van Vliet-Lanoë3, Stéphane Baize4, Isabelle Cojan5 1 Service Géologie et Environnements de surface - Andra (Andra/DRD/GES) – 1-7 Rue Jean Monnet 92298 Châtenay-Malabry, France 2 GEOTER - – Néant...
Conference Paper
Thermokarstic activities in Europe Brigitte van Vliet-Lanoë?1, Jacques Brulhet, Philippe Combes, Cédric Duvail, Frédéric Ego, Stéphane Baize2, Isabelle Cojan3 1 Domaines Océaniques (LDO) – CNRS : UMR 6538 – IUEM – Place N.Copernic, 29280 Plouzané, France 2 Institut de radioprotection et de sûreté nucléaire (IRSN) – BP17, 92262 Fontenay-aux-Roses Ce...
Conference Paper
Full-text available
Thermokarst is a collapse feature commonly described in former glaciated terrains or in present-day Arctic, especially with the Global Warming resulting from the thawing of ice-rich permafrost or of massive ice of various origins. This process is well observed and studied in Arctic. Little attention has been paid to the sedimentary fabric resulting...
Conference Paper
The Aptian-Albian transition was marked, in the platform domain (central Tunisia) by a major stratigraphic gap linked with a subaeral exposure. This gap was however recorded in the region of Sidi Bouzid by a non-marine series rich in charophytes, called "Kebar Formation". This formation -that was previously considered exclusively continental and re...
Conference Paper
Meandering fossil systems are very common in terrestrial systems. Meander loops development induced by the migration processes, although still debated, are attributed to the deformation of the velocity field in relation to the channel path irregularities. In the following, we propose a comparison of the channel and channel belt patterns obtained fr...
Conference Paper
Sinuous submarine channels are a very common feature of deep-water environments. The hydrocarbon reservoir potential of the associated deposits has been proved and many of them are exploited in several areas in the world. Several approaches exist to model submarine channels but all with limitations. The process-based and stochastic FLUMY model simu...
Article
Four stepped fluvial terraces along the Aube River Valley have been dated using the Electron Spin Resonance (ESR) method applied on optically bleached quartz. The obtained chronology indicates that the deposition of the terraces system was initiated during the Middle Pleistocene, i.e. later that in other valleys of Parisian Basin area (Cher, Creuse...
Article
Quatre nappes fluviatiles fossiles étagées sur les versants de la vallée de l'Aube ont fait l'objet de datations par la méthode de la résonance de spin électronique (ESR) appliquée aux grains de quartz optiquement blanchis. Les âges obtenus indiquent que la mise en place du système de terrasses alluviales s'est initiée pendant le Pléistocène moyen....
Poster
Full-text available
English version here : https://www.researchgate.net/publication/281989051_Process-based_modelling_for_a_finer_characterization_of_meandering_fluvial_reservoir_heterogeneities_FLUMY_and_the_Miocene_Loranca_Basin
Conference Paper
Full-text available
Les faciès typiques des Sables de Fontainebleau sont en fait secondaires, acquis tardivement, en liaison avec la mise à l’affleurement de la formation. Il n’y a guère que les figures sédimentaires qui peuvent être considérés comme primaires ! Tous les autres faciès considérés comme caractéristiques (grès, sables blancs, et même la composition minér...
Article
Full-text available
Des études physico-chimiques ont été effectuées sur les matières en suspension (MES) de la Seine, et plus particulièrement sur les phases sulfurées et oxydées porteuses de polluants métalliques. Les résultats montrent qu'il existe différents types de micropolluants métalliques liés aux particules de la colonne d'eau. Le fer est à la base de nombreu...
Conference Paper
Full-text available
Différentes structures superficielles de l’Est du bassin de Paris attestent de la présence de pergélisol continu lors des Derniers Glaciaires. Il s’agit de sols structurés périglaciaires, de traces de coins de glace bien exprimés en domaine crayeux. L’observation de carrières dans la région de Bure atteste de l’existence de figures qui peuvent êtr...
Article
This study examines the lateral distribution of hydromorphy in the fine-grained alluvial deposits of the Eocene Pondaung Formation, central Myanmar. Through detailed outcrop analysis and using a combined sedimentological and pedological approach, this study proposes a reconstruction of Pondaung overbank floodplain palaeoenvironments. The variations...
Article
Full-text available
Stable isotope (C and O) analyses were carried out on pedogenic nodules from carbonate-rich paleosols from early to middle Miocene strata in the Digne-Valensole foreland basin (southeast France). Paleosols from three sections corresponding to several paleoenvironments were sampled in order to investigate the local influence on the isotope record of...
Book
Une journée avec Bernard Beaudoin, en l'honneur de l'action qu'il a menée tout au long de sa carrière, pour le rayonnement de la sédimentologie française, est organisée par la Société Géologique de France, le Groupe Français du Crétacé, l'Association des Sédimentologistes Français et MINES ParisTech. Quatre thèmes parmi ceux qu'il affectionne ont é...
Article
Full-text available
Landscape evolution results of antagonistic processes. In the Paris basin (France): tectonic uplift seems to be globally balanced by river incision. But the dynamic equilibrium of the relief can be disturbed by other processes and singularities may appear. A remarkable example is observed in the Meuse basin (NE of France), where the river is actual...