Hugo Corbí

Paleoenvironmental changes during the late Miocene (Messinian)–Pliocene transition (Bajo Segura Basin, southeastern Spain): Sedimentological and ichnological evidence

ABSTRACT A detailed sedimentological and paleontological analysis of the uppermost Miocene (Messinian)–Pliocene boundary at the northern border of the Bajo Segura Basin, southeastern Spain, was carried out in order to describe the evolution of the regional paleocoastline during the Pliocene reflooding of the Mediterranean immediately after the sea-level fall related to the Messinian Salinity Crisis. Multiple trace fossils typical of firm- and hardgrounds were recognized, allowing identification of Glossifungites (two different types), Entobia, and Gnathichnus ichnofacies. Trace-fossil analysis showed that lithology and media consistency exerted considerable control on the development of the different ichnocoenoses and that there was a clear decrease in hydrodynamic energy from a coastal to a shallow-water shelf environment related to progressive sea-level rise. Ichnological and sedimentological data provide evidence that the definitive flooding of the Mediterranean was rapid and synchronous throughout the northern margin of the Bajo Segura Basin. The following model for the Pliocene transgression in the study area is therefore proposed: (1) the marine ingression penetrated along the incised paleovalleys carved as a consequence of the fall in sea level, where the first two Pliocene systems were deposited (P0–P1); (2) during the maximum flooding surface of the transgression, the sea overflowed the margins of the paleovalleys and extended throughout the entire northern margin of the basin; and (3) the third Pliocene system was deposited, forming the lower part of a highstand systems tract (P2).

Sierra del Colmenar 1A, a new late Messinian (Late Miocene) locality in the Bajo Segura Basin (SE Spain): biostratigraphic and palaeoenvironmental implications

Abstract In this paper, we have studied a new micromammal site from the Sierra del Colmenar section (Elche, SE Spain), named Sierra del Colmenar 1A (SCO-1A), representing the uppermost levels of Messinian age of the Bajo Segura Basin. The sedimentary context of this locality corresponds to a costal lagoon with marine influence. The fossil site has yielded remains of Apodemus aff. gorafensis, Paraethomys meini, Apocricetus alberti, Occitanomys alcalai, Ruscinomys sp., Eliomys cf. truci, Muscardinus sp., Parasorex ibericus, Prolagus michauxi and Soricidae indet. Based on this assemblage, we propose a Late Miocene age (MN13) for the locality SCO-1A, matching the previously inferred age for the stratigraphic unit in which the fossil site is situated. According to its faunal composition, we infer warm and humid climate conditions in the moment of formation of this locality, agreeing with the environmental conditions of the Messinian age in a parallic sedimentary context.

Potential Use of a Significant Scientific Geosite: the Messinian Coral Reef of Santa Pola (SE Spain)

The Messinian coral reef of Santa Pola, one of the most relevant geosites in the geological heritage of the western Mediterranean, is quantitatively assessed in terms of geoscience and features of potential use. Two different methodologies are used, one developed by the Geological and Mining Institute of Spain (IGME) for the Spanish Geosite Inventory (IELIG) and the other prepared by the Paleontological Museum of Elche (MUPE) for the Fossils and Heritage Project of Alicante (FOPALI). Santa Pola scores very high with both methods, which is a clear indication that this exceptionally relevant scientific geosite (included in the Spanish Geosite Inventory) also has a high didactic and tourism-recreational potential. In addition, the paper compares and discusses the two different methodologies, concluding that the selection of a model depends on the purpose of the evaluation (representativeness of the geosite in the Spanish territory associated to the Spanish Geological Inventory (IELIG) and a comparison of palaeontological and geological features (FOPALI) between different geosites). This work is a starting point to develop a specially designed management plan and geoconservation strategy for this exceptional geosite of the western Mediterranean.

El registro sedimentario de la Cuenca del Bajo Segura (SE España) a través del análisis de correspondencia: implicaciones paleoambientales

espanolSe ha analizado el registro sedimentario Messiniense y Plioceno de la Cuenca del Bajo Segura a traves del analisis multivariante de correspondencia sin tendencia (DCA). Los resultados obtenidos permiten examinar de forma integral y sintetica los ambientes sedimentarios y sintemas representados, atendiendo a la distribucion de foraminiferos bentonicos y planctonicos (grupos ecologicos) registrados en seis secciones representativas de la cuenca, tres en el borde norte (Colmenar, Torrellano y Elche), y otras tres en el borde sur (Garruchal, La Pedrera y El Canal). Del analisis estadistico, contrastado con las fuentes bibliograficas disponibles, se puede concluir que: a) el sector sur presenta en comparacion con el sector norte, una mayor diversidad de ambientes marinos; y b) los tres sintemas analizados presentan unas caracteristicas propias, en terminos de variedad y representacion de los ambientes sedimentarios registrados. EnglishThe Messinian and Pliocene record of the Bajo Segura Basin has been analysed by multivariate detendred correspondence analysis (DCA). The obtained results enables a comprehensive and synthetic examination of the sedimentary record, considering the distribution of benthic and planktic foraminifera (ecological groups) recorded in six representative sections of the basin, three on the northern sector (Colmenar, Torrellano and Elche) and three on the southern part (Garruchal, La Pedrera and El Canal). From the statistical analysis, contrasted with the bibliographical sources available, it can be concluded that: a) the southern sector presents, in comparison with the northern sector, a greater diversity of marine environments; and b) the three analysed synthems have their own characteristics in terms of variety and representation of their registered sedimentary environments.

The Littoral Bottoms of Benidorm Island (Western Mediterranean Sea): Eco-Sedimentological Characterization Through Benthic Foraminifera

Benidorm Island is one of the most relevant protected marine areas in the Province of Alicante (south-eastern Iberian Peninsula). Its bathymetric gradient and the structural complexity of the seabed make it an ideal place to analyse foraminifer assemblages considering depth and sediment type (particle size distribution). For this purpose, seven sampling sites representing the variety of littoral/sublittoral bottoms present have been sampled. The seabed sediment is composed mainly of gravelly sand with a high bioclastic content, abundant echinoderm fragments, sponge spicules, and bivalve and gastropod shell debris. We have documented a highly diverse community of benthic foraminifera dominated by epiphytic species. This work also examines the relation between depth (or open marine influence) and the planktonic foraminifer ratio, discussing the implications in the geological marine record. The distribution of some benthic foraminifer key species has been evaluated in this regard. The scuba dives performed also reveal possible environmental deterioration due to increased marine recreational activities, mostly scuba diving and boating. Finally, the littoral bottoms surrounding Benidorm Island would be an excellent area for future research using foraminifera as bio-indicators for monitoring environmental impacts on coastal regions.ResumenLa Isla de Benidorm es una de las áreas marinas protegidas más representativas de la Provincia de Alicante (sureste de la Península Ibérica). El gradiente batimétrico y la complejidad estructural de sus fondos litorales hacen de esta isla el lugar idóneo para analizar las asociaciones de foraminíferos, considerando tanto la profundidad como el tipo de sedimento (distribución de tamaño de partícula). Con este propósito, se examinaron 7 estaciones de muestreo representativas de la variedad de fondos litorales. El sedimento del fondo está compuesto principalmente por arena con grava y con un alto contenido en bioclastos (principalmente fragmentos de equinodermos, bivalvos, espículas de esponja y gasterópodos). Se ha documentado una alta diversidad en la comunidad de foraminíferos, dominados por especies epífitas. El artículo también examina la relación entre la profundidad (grado de influencia marina) y el porcentaje de foraminíferos planctónicos, discutiendo las implicaciones en los estudios del registro geológico marino. En este sentido, también ha sido evaluada la distribución de algunas especies clave de foraminíferos bentónicos. Las inmersiones realizadas ponen de manifiesto un posible deterioro ambiental debido al incremento de las actividades marinas recreativas, como buceo o navegación. Finalmente, el trabajo pone de manifiesto que los fondos marinos que circundan la Isla de Benidorm pueden ser un área marina idónea en futuras investigaciones donde se utilicen los foraminíferos como bio-indicadores del monitoreo de impactos medioambientales en regiones costeras.

Linking Geological and Architectural Heritage in a Singular Geosite: Nueva Tabarca Island (SE Spain)

This work presents the singular case of Nueva Tabarca island (SE Spain), which is an excellent example where stone-built monuments and historical quarries greatly enhance the geoheritage interest of this site. This small western Mediterranean island brings together a rich, diverse geological record and a baroque architectural heritage represented by a fortified village. The geoheritage constitutes the bedrock of the historical and architectural monuments. In addition, though, the building stones can be used to interpret the litho- and bio-facies, which provide significant geological knowledge to better understand the island’s geosedimentary history. Furthermore, the diverse settings of the building stones allow a didactic and integrated reading of the erosional processes that can affect these stones. In short, architectural heritage becomes an alternative tool to study geology and promote geoheritage. The characterization and inventory of the local geoheritage has allowed us to propose a geotourism route of ten sites of special interest. The sites were selected due to their relevance showing the geological context, the building stones used in the architectural heritage, and the conservation state and the weathering processes that affect rocks. This paper evidences that geosites can be of special significance, particularly in geotourism, precisely due to their huge potential to connect heritages of varied natures. The closer the links between geology, history, and architecture, the more people will be interested in and concerned about geoheritage.