A compilation of global bio-optical in situ data for ocean colour satellite applications – version three

A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data set comprises in situ observations of the following variables: spectral remote-sensing reflectance, concentration of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficient, and total suspended matter. Data were obtained from multi-project archives acquired via open internet services or from individual projects acquired directly from data providers. Methodologies were implemented for homogenization, quality control, and merging of all data. Minimal changes were made on the original data, other than conversion to a standard format, elimination of some points, after quality control and averaging of observations that were close in time and space. The result is a merged table available in text format. Overall, the size of the data set grew with 148 432 rows, with each row representing a unique station in space and time (cf. 136 250 rows in previous version; Valente et al., 2019). Observations of remote-sensing reflectance increased to 68 641 (cf. 59 781 in previous version; Valente et al., 2019). There was also a near tenfold increase in chlorophyll data since 2016. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented and it is also possible to analyse each set of data separately. The compiled data are available at https://doi.org/10.1594/PANGAEA.941318 (Valente et al., 2022)

Campagne océanographique GEOBLAVET

Campagne en mer réalisée du 15/09/2001 au 28/09/2001 par le LABORATOIRE GÉOSCIENCES OCÉAN (LGO) - UMR 6538 sur le ThaliaStudy of the Blavet (south Brittany) paléovalley system and of the different recent sedimentary units in the coastal areas of Southern Brittany in relation with the results of GEOVIL (June 1998) and GEODET (June 2000) surveys. In September 2000, this was to contribute to the specification, comparison and quantification of the various deposit sequences preserved on the scale of the contemporary South Brittany domain, in the recent history of the Armorican Massif. The cruise fell under the COTARMOR project (headed by Jean-Noel Proust).Exploration de la nappe sédimentaire côtière entre la cote et l'isobathe 50 mètres en Bretagne Sud. Cette étude porte principalement aux débouches: (1) du Blavet et du Scorff, et de son raccordement avec l'Odet (2) de la rivière d'Etel (3) du Mors Bras (Baie de Quiberon et de Vilaine). Cette campagne complète et assure le lien avec les 2 précédentes missions GEOVIL (Juin 98) et GEODET (Juin 2000). Septembre 2000. Il sera alors possible de préciser, comparer, quantifier les différentes séquences de dépôt préservées à l'échelle du domaine sud breton contemporain de l'histoire récente du Massif armoricain. Le projet de rattachement est COTARMOR (Responsable Jean-Noel Proust)

Campagne Océanographique GEODET 1

Campagne en mer réalisée du 05/06/2000 au 16/06/2000 par le LABORATOIRE DE GEOSCIENCES - UMR CNRS 6118 sur le ThaliaGEOFRANCE 3D ARMOR2 project, geomorphology and neo-tectonic subproject: study in 3D of the sedimentary filling of the Geodet (Southern Brittany - France) paleovalley system in the coastal areas. High resolution reflection seismics (sparker 250j, 1 channel), multibeam bathymetry EM1000), Shipeck grab (samples).Géométrie 3D du remplissage des paléovallées de l'Odet (Bretagne Sud). Le projet de rattachement est GEOFRANCE 3D ARMOR2 volet "Géomorphologie et Tectonique récente"

Evolution of sedimentary architecture in retro-foreland basin: Aquitaine basin example from Paleocene to lower Eocene

International audienceThe Aquitaine basin located in south western Europe, is a Pyrenean retro-foreland basin. Two main phases of compression are recorded in this retro-foreland basin during the Pyrenean orogeny. A first upper Cretaceous phase corresponding to the early stage of the orogeny, and a second one usually related to a Pyrenean paroxysmal phase during the middle Eocene. During Paleocene to lower Eocenedeformations are less pronounced, interpreted as a tectonically quiet period. The aim of the study is to better constrain the sedimentary system of the Aquitaine basin during this period of Paleocene-lower Eocene, in order to discussthe evolution of the sedimentary architecture inresponse ofthe Pyrenean compression. This work is based ona compilation of a large set of subsurface data (wells logs, seismic lines and cores logs) represented byisopachs and facies map. Three main cycles were identified during this structural quiet period: (1) The Danian cycle, is recorded bythe aggradation of carbonate reef-rimmedplatform. This platform is characterized by proximal facies (oncoid carbonate and mudstone with thalassinoides) to the north, which leads to distal deposit facies southern(pelagic carbonate with globigerina and slump facies) and present a significant thickness variation linked to the platform-slope-basin morphology. (2) The upper Selandian-Thanetiancycle follows a non-depositional/erosional surface associated with a Selandian hiatus.The base of this cycle marked the transition between the last reef rimmed platform and a carbonate ramp. Thetransgressive cycle is characterized by proximal lagoon facies to the north that leads southwardto distal hemipelagic faciesinterfingeredbyturbiditicLowstand System Tracks (LST). The location of these LST isstrongly controlled by inheritedDanian topography. The regressive cycle ends with a major regression associated with an erosional surface. This surface is linked witha network of canyons in the north, an important terrigeneous LSTand a massive erosional surface in deep basin. We correlated this upper Thanetianmajor regression with a flexural deformation of the basin. In this context, the importance of terrigeneous LST could be explained by the erosion of the East Pyrenean range. (3) The lower Ypresian recordsthe installation ofmixed terrigenous-carbonated system.While theEast-West progradation ofsiliciclastic deltas is drained into foreland basin, a carbonates condensation are developed on structural ridges, attesting the structural activation of foreland basin during lower Ypresian. This study shows thatDanian to middle Thanetian time represents a quiet tectonic period in the retro-foreland basin. During the upper Thanetian period, the compressive deformation is increasing, marked by the emersion of the northern platform, a massive LST in deep basin anda riseof terrigenousinput in flexural basin (LST). This deformation associated with the Pyrenean compression continues during the Ypresian and highlights the paroxysm of the Pyrenean orogeny. This work is included in the Gaia project founded by TIGF, BRGM and Agence de l'Eau Adour/Garonne whose aim at constrain the nature and dynamics of deep Upper cretaceous and Tertiary aquifers of the Aquitaine basin

The paleo-Etel River incised valley on the Southern Brittany inner shelf (Atlantic coast, France): Preservation of Holocene transgression within the remnant of a middle Pleistocene incision?

International audienceThe study of a dense and regular grid of 59 High Resolution seismic profiles supplemented by 23 superficial vibro-cores has led to propose a three-dimensional detailed sedimentary model of the paleo-Etel River buried valley located on the inner shelf of South Brittany (Atlantic Coast, France). This fluvial valley (S2) lies at a mean depth of − 37 m below mean sea level above Paleozoic meta-sediments (U1) and middle to late Eocene formations (U2). No fluvial deposits seem to have been preserved. Its sedimentary record reflects the retrogradation of estuarine environments (tidal flats (U3), Tidal Ravinement Surface (S3), and intra to pro-estuarine sand bars (U4/S4/U5)) during the Holocene transgression (ca. 9000 to 7500 cal yr BP). Open marine environments seal up this estuary with the onset of a flat Wave Ravinement Surface (S5) overlain by thin muddy-sands deposits (U6-F2) interpreted as low-energy open marine conditions (4250 to 1800 cal yr BP). Shoreface sands, made up of coarse sands bodies migrating landwards (U6-F3, F4), cover this sedimentary sequence since 1800 cal yr BP. A numerical interpolation of the picked seimic horizons was proceed to produce seismic isopach maps of sedimentary units and isobath maps of their boundary surfaces. Furthermore, the isobath map of the basal channel topography has enabled us to calculate some geomorphological features (W/D ratio, mean slope, sinuosity index) that characterized the type of channel pattern. The Etel River geomorphological indexes correspond to a straight channel that involves bed-load transportation processes, potentially associated to braided deposits if the sediment load is sufficient. Compared to the Vilaine River, which braided regime is dated at middle Pleistocene in several zones, we assume a possible mainly climatic control for river incisions in Southern Brittany linked to drastical changes in climate regimes occurring during the "Middle Pleistocene Transition"

Sedimentary record of the Paleogene deformation in the North Pyrenean retroforeland (Aquitaine Basin) and link to the Pyrenean orogeny.

International audienceThe North Pyrenean retroforeland (Aquitaine basin) display a quite different tectonic style compared to its well known southern counterpart, and is not well known due to a lack of accurate stratigraphy and geometry at the scale of the basin. Strong efforts have been made in the recent years to improve the knowledge of the Pyrenean orogeny and Aquitaine basin. Based on the integration of more than 1000 wells and 10000 km of seismic profiles we present a synthesis of the Paleogene sedimentary record of the Aquitaine Basin. Large-scale sections, thickness and facies map at the scale of 1 My, precise the timing, intensity and distribution of the deformation. Within Cenozoic, five major tecto- sedimentary cycles are identified, 2 Paleocene cycles :A Danian-Selandian cycle (P1), and a Thanetian one(P2)., And 3 Eocene cycles:- An Ypresian- Lower Lutetian cycle (E1) composed of prograding deltas.- A Lutetian- Bartonian cycle (E2) composed of mixed carbonate siliciclastic deposits.- A Priabonian cycle (E3) marked by a large scale infilling of the basin and deposition of fined- grained continental sedimentation.The timing of deformation is refined and confirms the occurrence of a relatively quiet period during Paleocene (Danian- Lower Thanetian) although with progressively increasing sedimentation rate, followed by a syn orogenic period during Eocene. The latter is separated in two steps:- Firstly the development of a large-scale flexural basin during Early Eocene. Onset of (lim- ited) thrusting and fault reactivation is registered around Paleocene- Eocene boundary in the eastern part of the basin.- Secondly a propagation of the brittle deformation in the foreland with strong inversion and thrusting in the foreland (Audignon etc.) and complete spatial reorganization of the subsidence pattern.- A Priabonian phase of homogenous moderate subsidence during Priabonian, particularly in the eastern part of the basin.This evolution is congruent with the southern foreland one and traduces common phases of evolution. The Ypresian- Lutetian period flexure is interpreted as the consequence of the loading by the growth of the orogenic prism that took place at that time and possibly started earlier during Paleogene. The Bartonian compressive deformation of the foreland correspond to the major phase of collision. These results were acquired during the Gaia project founded by TIGF, BRGM and Agence de l’Eau Adour/Garonne

Buried fluvial incisions as a record of Middle–Late Miocene eustasy fall on the Armorican Shelf (Bay of Biscay, France)

International audienceHigh-resolution seismic data have been acquired in June 2008 on the Armorican Shelf (AS), in the northern Bay of Biscay, in order to reassess its stratigraphic architecture in detail and to study the impact of eustasy, tectonic and sediment delivery on the margin sedimentary record. Several profiles show fluvial-type incisions of several tens of meters (up to 54 m) associated to a widespread erosion surface. Several hypotheses are proposed for the stratigraphic position of this surface and incisions. We suggest Middle to Late Miocene age. Considering the relatively quiescent tectonic activity of the margin, we infer that the relative sea-level fall responsible of aerial incision on the Miocene shelf is eustasy-related. We propose the attested Serravallian–Tortonian eustatic lowstand (c. 11.6 Ma) as the key event responsible of such erosion and incision. This event marks the early beginning of the high-amplitude sea-level fluctuations that culminated during the Pleistocene and significantly controlled the present day AS morphology. The variability of vertical incision observed along single reaches can be explained by the confluence of several tributaries, the sinuosity of the channel and can be amplified by the unconsolidated nature of the Miocene substratum. The main pathways of the fluvial network corresponding to these buried valleys have been reconstructed and connections to other existing networks are proposed

Les vallées fossiles de la baie de la Vilaine : nature et évolution du prisme sédimentaire côtier du Pléistocène armoricain

International audienceL'étude d(un maillage serré de profils sismiques Sparker haute résolution, obtenus en baie de Vilaine (mission INSU-CNRS Géovill), a permis de mettre en évidence la structure du prisme sédimentaire côtier, préservé entre les côte et l'isobathe -50 m, en Bretagne sud. Ce prisme repose sur un substratum qui montre trois entités sismiques U1, U2, U3 attribuées respectivement au socle métamorphique et magmatique, aux grès et calcaires gréseux yprésiens et lutétiens et aux séries sédimentaires post-éocènes. le prisme côtier comprend trois unités sismiques principales. Une unité basale (U4), interprétée comme des dépôts fluviatiles en tresse, qui pourrait correspondre aux séries datée à terre de 600 à 317 ka BP. Une unité médiane (U5) d'âge inconnu correspondant à des dépôts fluviatiles méandriformes et estuariens passant vers l'ouest à des dépôts d'embouchure. Une unité sommitale (U6) comprenant des argilites marines et des systèmes littoraux de type barrière dont la base est datée de 8 110±200 ans. Ces trois dernières unités sont séparées par deux discontinuités majeures. Une "unconformity" ou limite de séquence entre U4 et U5 et une surface de ravinement par la houle et les marées entre les unités 5 et 6. Ces surfaces limitent deux séquences à l'intérieur du prisme côtier : une séquence basale (U4) et une séquence sommitale (U5 et U6).Par analogie avec l'évolution décrite à terre, la séquence basale est attribuée au cycle glaciaire saalien et/ou elstérien et la séquence sommitale au cycle weichsélien (cortège de bas niveau) et à la transgression marine holocène (cortège transgressif). Toutefois, le passage d'une séquence à l'autre correspond à un changement de 60°, des directions d'écoulement des paléofleuves bretons en baie de Vilaine dont l'orientation suit celle des principaux réseaux de fractures régionaux. Ainsi, l'activité de la Bretagne au Pléistocène, liée aux contraintes intraplaques, pourrait être à l'origine de la distribution des corps sédimentaires dans le prisme côtier sud breton. En effet, le basculement du Massif Armoricain au cours de cette période a provoqué un rajeunissement complet des profils fluviatiles régionaux et peut-être la fin de la capture de la Paléovilaine par la Paléoloire