Stratigraphical response to the Tortonian Transgression in the Guadalquivir Foreland Margin: A preliminary approach

The passive margin of the Guadalquivir foreland basin records different stages of evolution during the tortonian transgression, mainly determinate by sedimentary supply/ accommodation space ratio (A/S ratio, Cattaneo and Steel, 2003). In a first phase, a high supply from the continental and deltaic systems filled quickly the low accommodation space and produced an agradational/progradational stacking pattern of sequences. The second episode is characterized by a change in these conditions, so the passive margin register a high increase of depth and carbonate facies predominates. Finally, the transgressive maximum is registered by means of the formation of a condensed level constituted by glauconitic sands and silts. This transgressive pulse supposed the advance of the shoreline several kilometres towards the forelan

Geological researchs along the Coast of Huelva: Balance and perspectives

Research results of works developed along the Huelva coast, s. w. Spain, are commented. The concept of coast is Introduced within the Interdisciplinary contributions of its studies from the classic antiquity. It Is concluded with a perspective of future research lines centered on: (1) the modeling of high-resolution seismic reflections of the Holocéne infilling; (2) increase of radiometric dating (l4C,210Pb, etc.) of coastal sequences as related to recent sea-level fluctuations; (3) increase of the vibracoring networt on Holocene sediments; (4) determination of the origin and evolution of the geochemical composition ofthe Holocena sediments; and (5) modelling of the sedimentary transfer continent/ocean along the Gulf of Cadi

Facies deposicionales Holocenas de la Costa de Huelva : propuesta de nomenclatura para litofacies estuarinas

Las facies deposicionales holocenas que aparecen a lo largo de la costa de Huelva se han agrupado en nueve conjuntos: (1) barra fluvial lateral, (2) llanura de inundación fluvial, (3) canal estuarino, (4) canal mareal, (5) borde de canal, (6) llanura mareal, (7) delta mareal, (8) marisma safada y (9) flecha litoral arenosa. Se propone una nomenclatura y clasificación de litofacies estuarinas, terminología descriptiva, e identificadas en diferentes medios costeros relacionados, en las que se utilizan letras mayúsculas para indicar la litología, letras minúsculas para las estructuras sedimentarias físicas, una letra griega para el tipo de bioturbación y un número para el grado de bioturbación. Las diferentes litofacies individuales distinguidas se agrupan, así, en nueve conjuntos de litofacies: (1) gravas, (2) acumulaciones orgánicas vegetales, (3) acumulaciones de conchas, (4) arenas limpias bioturhadas, (5) arenas limpias sin bioturbar, (6) arenas fangosas, (7) fangos arenosos, (8) fangos sin bioturbación y (9) fangos bioturbados. Estos conjuntos de litofacies se interpretan según facies deposicionales, con indicación de las litofacies estuarinas individuales, que las componen, y las variaciones laterales, verticales y longitudinales que muestran a lo largo de los diferentes sectores estuarinos. La aplicación de la nomenclatura propuesta facilita: (1) la síntesis de las facies presentes en los estuarios actuales y (2) la descripción de facies en los estuarios antiguos y su comparación con los actuales.Depositionail holocene facies identified along the Huelva coast, southwestern Spain, are joined mb nine sets: (1.) lateral-fluvial bars, (2) fluvial flood plain, (3) estuarine channel, (4) tidal channel, (5) channel-margin, (6) tidal fiat, (7) tidal delta, (8) salt-marsh and (9) sandy spit. A nomenclature of estuarine lithofacies, descriptive terrninology, as identified in differentand rdated coastal environments is proposed. Estuarine lithofacies can be classified according to capital letters to represent lit.hology, small letters forphysical sedimentary structures, a Greek letter for burrowing type ané, finally, a number to indicate trw burrowing degree. Nine estuarine lithofacies groups with vanous assoeiations of individual litliofacics aire distinguished: (1) gravels, (2) plant-derived organic accumulations, (3) shell accumulations, (4) burrowed clean sands, (5) unburrowed clean sands, (6) muddy sands, (7) sandy muds, (8) unburrowcd muds and (9) burrowed muds. Depositional facies occurred along the Huelva coast, with indication of every associated estuarine lithofacies group, are interpreted showing their lateral, vertical and longitudinal variability as occurred along the different estuarine domains. The application of the proposed nomenclature contribute to: (19 make the synthesis of the facies showed on the modem estuaries and (2) to facilitate the facies description in the oid estuaries as well as its comparison with thc modern ones

The fluvial braided facies in the Pleistocene from Isla Cristina (Huelva)

Various facies sequences generated in a fluvial regime of braided type are identiffied in a series atributed to the Pleistocene from Southwestern Huelva (Southwestern Spain). Channel and bar facies are mainly represented. These data allow to extend to the west the same conclusion that have been pointed out in another relationed secto

Submedios asociados a un sector intermareal de la ría de Huelva

Varios sedimentary subenvironments relationed to the Huelva Ria are described. In this way there are identified the active channel-margin, the salt-marsh and the sterilemarsh environments. The sequenial arangement is of clear regressive affinit

Morphodynamic elements responsibles of modern evolution of Guadiana River marine estuary (Huelva, SW Spain)

Guadiana estuary is located along the mesotidal coast of Huelva (SW Spain) and their modern configuration has been traditionally interpreted in terms of interaction among: 7) Litoral drift; 2) tidal range and 3) Fluvial supply. According to modern sedimentary evolution of this stuary, the interaction of both currents entering/exiting the estuary (flood, ebb and fluvial currents) and flood/ebb tidal currents which goes para/ell to shoreline at externa/ litoral zones can be regarded as the driving process of modern coastal configuratio

Iron sulfides formation in modern estuaries: some genetic considerations

Iron sulfides found in estuaries located along the mesotidal coast of Huelva (SW Iberia) show various kinds of occurrence and allow to infer their genesis as an early diagenetic process. Sediment burial produces the alteration of organic matter and the reduction of ferric iron which reacts with amorfous iron grains supplied by Plio-Pleistocene sediments from the substrate. Sulfates supplied by marine waters can produce reduction of sulfur. Iron sulfides precipitation is then taken into accoun

Derived effects of Artificial Constructions on Growth Patterns from El Rompido Spit (Huelva, SW Spain)

Factors which mainly controls the evolution of depositional environments along the mesotidal coast of Hue/va (SW Spain) are: 7) Sediment supply; 2) Hydrodynamic setting and 3) Artificial constructions. These factors are taken into account in this note to analyse growing in the recent past of a spit located along Piedras River mouth. It is concluded that decreasing of tidal prisma entering this estuary, caused by both natural and artificial factors, is the responsible of spit growt