Analysis of water erosion using GIS and remote sensing for the management of protected natural environments in the south of the province of Salamanca (Spain)

Resumen del trabajo presentado al IV International Symposium on Gully Erosion, celebrado en la Universidad Pública de Navarra del 17 al 19 de septiembre de 2007.The soil is a natural resource that must be conserved in protected natural areas since it is one of the determinant physical supports in territorial planning because it governs its different uses. Accordingly, specific studies must be carried out aimed at estimating soil losses at individual project level and at the general level of Natural Environments in order to establish methodologies for the control and ordering of activities, above all in protected environments whose focus is on sustainable activities. The basic objective should delimit different erosive forms where best it reflects the risk of water erosion (gullies, rills) and the degree (weak, light, important, and burden) and the processes induced (slides, scarp, remontant erosion...) in addition the evolution with time.Part of the work reported in this paper was financially supported by the GCL 2005-04655/BTE and CGL 2005-01336/BTE Projects

Pampa del Palo : an anomalous composite marine terrace on the uprising coast of Southern Peru

Quaternary sediments along the southern Peruvian coast occur as staircase terraces of coastal and shallow-marine deposits in response to continuous uplift related to the active boundary between the Nazca and South-American plates. However, near Ilo (in the same coastal stretch) the emergent Pampa del Palo terrace consists of a relatively-thick, vertical stack of shallow-marine, coastal and lagoonal deposits that indicate a rather different geodynamic behaviour. Coastal deposits are correlatable with the successive marine highstands of isotopic stages 7 (?) and 5 (substages 5e and 5c). Combining aerial photo-interpretation, geomorphological mapping, sedimentological analysis, chronostratigraphical data, and structural observations, the Pampa del Palo feature is interpreted as a faulted block that moved independently of the remaining southern Peruvian coast and, for some time between the end of Middle Pleistocene (before ca. 220 ka) and the early Late Pleistocene (ca. 120 ka), it rose more slowly or was even down-faulted relative to the rest of the southern Peruvian margin. The independent block movements ceased after substage 5e, when the Pampa del Palo "terrace" was incorporated into the regional uplift of the area. Since ca. 100 ka, measured uplift rate in the Ilo area amounted up to 160 mm/1000 y when the area has been affected by a few active, NE-SE trending faults only. (Résumé d'auteur

Did Strombus survive the Last Interglacial in the Western Mediterranean Sea?

El litoral de Almería constituye el sector más rico del Mediterráneo en niveles tirrenienses, todos ellos conteniendo Strombus bubonius. Cuatro playas diferentes se observan al Este de Almería, la más reciente, datada en 37.720 ± 1.740 años BP (14C) y 39.000 ± 2.000 años BP (Th/U) años BP, está claramente encajada en las anteriores, y a su vez se presenta relacionada con depósitos continentales de abanicos aluviales que constituyen los sistemas más recientes de la costa oriental de Almería. Por otro lado los depósitos tirrenienses de esta región constituyen un claro ejemplo de la distinta distribución espacial de los niveles con S. bubonius, tanto en lo que se refiere al número, cota, o incluso disposición geométrica de los mismos que depende fundamentalmente del marco neotectónico en el que se desarrollen. Por otra parte los autores hacen una llamada de atención sobre el empleo del término «Tirreniense» sugiriendo que se continúe utilizando a éste en el sentido de su definición original «capas que contienen S. bubonius» sin darle un sentido cronoestratigráfico estricto. Asimismo y a la vista de los resultados sería conveniente llevar a cabo una revisión sobre la significación climato-estratigráfica de la entrada del S. bubonius en el Mediterráneo.The warm gastropod Strombus bubonius spread into the Mediterranean Sea during the last interglacial period. Its fossil ocurrence is normally used as a climatostratifraphic indicator of the Tyrrhenian transgression and linked to high sea levels of this episode. However, a sequence of four successive and discordant stratigraphic units containing S. bubonius is observed in the Rambla Amoladeras-Rambla Sepultura compisite section, east of Almería, on the Spanish Mediterranean coast. The youngest unit has been dated between 39.000 and 34.000 y BP, suggesting therefore that S. bubonius survived the last interglacial in the western part of the Mediterranean basin. Reconsideration of the use and meaning of the term «Tyrrhenian» and of the current somewhat confusing terminology is thus required.This study was supported by the Spanish CAICYT (Grant 3.228/79)

Medios marinos y marinos-salobres en la Bahía de Cádiz durante el Pleistoceno

La Bahía de Cádiz se instala en el labio hundido de una falla de direcció ENE- OSO que pasa al pie de la Sierra de San Cristóbal y que se continúa al Norte de El Aculadero. Los materiales del Plioceno superior «facies ostionera» fosilizan en muchos casos este accidente. Esta zona deprimida fue propicia a la permanencia de ambientes marinos y costeros durante la regresión generalizada del Plioceno superior y Pleistoceno. Las secciones estudiadas muestran megasecuencias transgresivas separadas por épocas de emersión asociadas en muchos casos con procesos de karstificación. A partir de estas series se deduce que durante el Plio/Pleistoceno lacosta formaba un amplio entrante entre Rota y la Barrosa (Chiclana de la Frontera) que se extendía por la parte inferior del valle del Guadalete, siendo la Sierra de San Cristóbal el relieve que constituía durante el Plioceno superior el acantilado fósil y dejaba en su interior dos islas. Cerro Centa y Cerro de los Mártires. La retiradaz del mar indujo a la formación de marismas y lagoones marino-salobres que· estaban separados del mar abierto por islas barreras que fueron invadidas repetidamente por el mar durante el Pleistoceno merced a oscilaciones positivas del nivel del mar con un valor «relativo» de 10-15 metros. El esquema de distribución de ambientes es semejante al actual en el que la flecha de Valdelaguana actúa como isla barrera entre el mar abierto y las marismas que, hacia tierra se interdigitan con conos de deyección y coluviones. Las dimensiones de la Bahía se han reducido con el tiempo.The Bay of Cádiz occupies a depression due to a fault bearing ENE - OSO, which is observed from the foothills of the San Cristóbal Sierra to the El Aculadero area, more to the north. This tectonic accident is covered by undisrupted sediments of upper Pliocene age (Facies Ostionera) in several places. Despite the general regressive trend which characterize the late Pliocene and Pleistocene ages, marines or littoral environments maintained in the Bay of Cádiz in relation to its depressed situation. The studied successions show transgresive megasequences separated by regressive episodes with karstification. A big bay existed in those times (Plio/Pleistocene) between Rota and La Barrosa (Chiclana de la Frontera) which extended along the valley of the Guadalete River, just by the paleo cliff of Sierra de San Cristóbal. Two islands corresponding to the Cerro de Centa and Cerro de los Mártires emerged. The general retreat of the sea eventually led to the development of barrier islands, lagoons and marshes that were repeatedly inundated during the Pleistocene due to positive oscillations of the «relative» sea level averaging 10-15 m. The pattern of sedimentary environments is fairly similar to the present-day model which the Valdelagrana spit bar acts as a barrier island placed between the open sea and the lagoon (marismas) that interfinger to the land with alluvial fan and colluvial continental environments. The size of the paleo-bay has decreased with time

Coseismic VS climatic effects in the record of relative sea-level changes: an example from last interglacials in SE Spain.

Trying to decipher how palaeoseismic activity has influenced the altitudinal disposition of interglacial deposits is one of the main challenges that must be achieved in order to quantify relative sea-level changes between consecutive highstands. Likewise, identifying palaeoseismic features in an area with low instrumental seismic activity can implement the seismic record and contribute to better seismic hazard knowledge. In this sense, Cope basin (SE Spain) becomes a reference basin to undertake this kind of analysis, firstly because of excellent outcrop conditions and secondly because the sea-level record is undoubtedly conditioned here by both effects: climatically driven changes and local and regional seismotectonics

Sea level and climate changes during OIS 5e in the Western Mediterranean

Palaeontological, geomorphological and sedimentological data supported by isotopic dating on Oxygen Isotopic Stage (OIS) 5e deposits from the Spanish Mediterranean coast, are interpreted with the aim of reconstructing climatic instability in the Northern Hemisphere. Data point to marked climatic instability during the Last Interglacial (OIS 5e), with a change in meteorological conditions and, consequently, in the sedimentary environment. The oolitic facies generated during the first part of OIS 5e (ca. 135 kyr) shift into reddish conglomeratic facies during the second part (ca. 117 kyr). Sea surface Temperature (SST) and salinity are interpreted mainly on the basis of warm Senegalese fauna, which show chronological and spatial differential distribution throughout the Western Mediterranean. Present hydrological and meteorological conditions are used also as modern analogues to reconstruct climatic variability throughout the Last Interglacial, and this variability is interpreted within the wider framework of the North Atlantic record. All the available data indicate an increase in storminess induced by an increase in the influence of northwesterlies, a slight drop of SST in the northern Western Mediterranean, and an important change in meteorological conditions at the end of OIS 5e (117 kyr). These changes correlate well with the decrease in summer insolation and with the climatic instability recorded in North Atlantic high latitudes

Sea level changes during the last and present interglacials in Sal Island (Cape Verde archipelago)

Last interglacial and Holocene deposits are particularly well developed in the southern parts of Sal Island (Cape Verde Archipelago). They primarily consist of low-elevation (≤2 m above sea level [a.s.l.]) marine deposits made of a basal conglomerate embedded in carbonate mud, passing upwards to calcarenites. All deposits contain an abundant fauna with corals, algae and molluscs with Strombus latus Gmelin and accompanying warm water species of the “Senegalese” fauna. Small scale geomorphological mapping with detailed morphosedimentary analysis revealed lateral facies changes and imbricate (offlapping) structures that suggest small-scale oscillations of paleo-sealevels during high sea stand intervals. U-series measurements (in coral fragments) allowed unequivocal identification of Marine Isotope Substage (MIS) 5.5 units, but were not precise enough to date the sea level oscillations of the interval. However, geomorphological data and sedimentary facies analysis suggest a double sea level highstand during the peak of the last interglacial. MIS 5.5 age deposits occur at Sal and the Canary Islands at low topographic elevations, between 1 and 2 masl. However, these values are lower than the elevations measured for the correlative terraces outcropping at the western tropical Atlantic islands, widely considered to be tectonically stable. Combining the results in this paper with earlier investigations of the “Senegalese” fauna distribution as far north as the Mediterranean basin, it is suggested that the last-interglacial oceanic temperatures in this basin, as well as the temperatures in other islands of the Eastern Atlantic and the coasts of Morocco, were warmer than modern temperatures

XE7: A novel splicing factor that interacts with ASF/SF2 and ZNF265

Pre-mRNA splicing is performed by the spliceosome. SR proteins in this macromolecular complex are essential for both constitutive and alternative splicing. By using the SR-related protein ZNF265 as bait in a yeast two-hybrid screen, we pulled out the uncharacterized human protein XE7, which is encoded by a pseudoautosomal gene. XE7 had been identified in a large-scale proteomic analysis of the human spliceosome. It consists of two different isoforms produced by alternative splicing. The arginine/serine (RS)-rich region in the larger of these suggests a role in mRNA processing. Herein we show for the first time that XE7 is an alternative splicing regulator. XE7 interacts with ZNF265, as well as with the essential SR protein ASF/SF2. The RS-rich region of XE7 dictates both interactions. We show that XE7 localizes in the nucleus of human cells, where it colocalizes with both ZNF265 and ASF/SF2, as well as with other SR proteins, in speckles. We also demonstrate that XE7 influences alternative splice site selection of pre-mRNAs from CD44, Tra2-β1 and SRp20 minigenes. We have thus shown that the spliceosomal component XE7 resembles an SR-related splicing protein, and can influence alternative splicing