Turbiditic levee deposition in response to climate changes: The Var Sedimentary Ridge (Ligurian Sea)

The Var turbiditic system located in the Ligurian Sea (SE France) is an intermediate mud/sand-rich system. The particularity of the Var deep-sea fan is its single channel with abrupt bends and its asymmetric and hyper-developed levee on the right hand side: the Var Sedimentary Ridge. Long-term sediment accumulation on the Var Sedimentary Ridge makes this an ideal target for studying the link between onshore climate change and deep-sea turbidite stratigraphy. This paper focuses on the establishment of the first detailed stratigraphy of the levee, which is used to analyze the timing of overbank deposition throughout the last deglaciation. Main results indicate that high variability in turbidite frequencies and deposition rates along the Var Sedimentary Ridge are determined by two main parameters: 1) the progressive decrease of the levee height controlling the ability of turbidity currents to spill out from the channel onto the levee, and 2) climatic variations affecting the drainage basin, in particular changes in glacial condition since late Last Glacial Maximum to early Holocene. Compared to other deep-water areas, this study confirms the ability of turbiditic systems to record past climatic events on millennial timescales, and underlines the influence of European deglaciation on the observed decrease in turbidite activity in the Var canyon. The presence of a very narrow continental shelf and a single, large channel-levee system makes the Var Sedimentary Ridge a unique example of climate-controlled turbiditic accumulations.     

Creative economy and employment quality in large urban areas in Spain

The impact of the economic crisis should act as an incentive to devise less vulnerable economic development models for Spanish cities. This study confirms that the impact of the creative economy, one of the most interesting initiatives in this context, remains very limited. Furthermore, microdata obtained from a sample of one million workers in Spain, published annually by the Social Security system, confirm that the sharp contrasts emerging in employment quality between sectors and regions, the processes of ‘precariousness of talent’ and labour dualization expressed through inequalities in the occupational structure are each becoming significant threats to viable economic development. For the creative economy to be an effective instrument for metropolitan regeneration, adapted to suit the specificities of particular urban development paths, an improved understanding of the inherent complexity of creative-economy employment relations is required.     

Unexpected records of ‘deep‐sea’ carnivorous sponges Asbestopluma hypogea in the shallow NE Atlantic shed light on new conservation issues

Marine cave communities have been a continued source of ecological surprises, among other things because of their close ecological and evolutionary ties with the deep sea. The discovery of cladorhizid sponges, the deepest occurring poriferan family, in shallow Mediterranean caves in the 1990s was one such surprise, leading to the generally accepted hypothesis that the whole family was carnivorous, an unprecedented feeding mode for sponges. The recent observation of the cave species Asbestopluma hypogea in the Mediterranean bathyal, confirmed the view that some shallow caves can occasionally shelter otherwise deep‐dwelling species. Here we present new distribution data of A. hypogea, from deep Mediterranean locations, and for the first time from Atlantic locations. Among the new Atlantic records, the most surprising ones are located in three different geographic areas (Ria de Arousa, Groix Island and Cherbourg) of the NW European coasts, from the Iberian Peninsula to the English Channel, where A. hypogea reaches SCUBA depths (5–50 m), while not sheltered in marine caves. The carnivorous sponge however reaches its shallowest occurrence (5 m), in a small cave at Groix Island. The ecological significance of these discoveries, particularly the very patchy distribution and peculiar dynamics, are noteworthy, and the shallow occurrence of A. hypogea, together with other deep‐water or uncommon species, constitute unique assemblages that must be considered in conservation plans.     

Non-explosive magma–water interaction in a continental setting: Miocene examples from the Eastern Cordillera (central Andes; NW Argentina)

The Middle-Upper Miocene Las Burras–Almagro-El Toro (BAT) igneous complex within the Eastern Cordillera of the central Andes (∼24°S; NW Argentina) has revealed evidence of non-explosive interaction of andesitic magma with water or wet clastic sediments in a continental setting, including peperite generation. We describe and interpret lithofacies and emplacement mechanisms in three case studies. The Las Cuevas member (11.8 Ma) comprises facies related to: (i) andesite extruded in a subaqueous setting and generating lobe-hyaloclastite lava; and (ii) marginal parts of subaerial andesite lava dome(s) in contact with surface water, comprising fluidal lava lobes, hyaloclastite, and juvenile clasts with glassy rims. The Lampazar member (7.8 Ma) is represented by a syn-volcanic andesite intrusion and related peperite that formed within unconsolidated, water-saturated, coarse-grained volcaniclastic conglomerate and breccia. The andesite intrusion is finger-shaped and grades into intrusive pillows. Pillows are up to 2 m wide, tightly packed near the intrusion fingers, and gradually become dispersed in the host sediment ≥50 m from the parent intrusion. The Almagro A member (7.2 Ma) shows evidence of mingling between water-saturated, coarse-grained, volcaniclastic alluvial breccia and intruding andesite magma. The resulting intrusive pillows are characterized by ellipsoidal and tubular shape and concentric structure. The high-level penetration of magma in this coarse sediment was unconfined and irregular. Magma was detached in apophyses and lobes with sharp contacts and fluidal shapes, and without quench fragmentation and formation of a hyaloclastite envelope. The presence of peperite and magma–water contact facies in the BAT volcanic sequence indicates the possible availability of water in the system between 11–7 Ma and suggests a depositional setting in this part of the foreland basin of the central Andes characterized by an overall topographically low coastal floodplain that included extensive wetlands.     

Groundwater salinization in the Azores archipelago (Portugal)

Groundwater salinization in coastal regions causes severe constraints to water supply and economic losses to society worldwide. In the Azores archipelago, groundwater abstraction in wells drilled in coastal aquifers is very important for water supply, and quality problems have been reported. Therefore, a groundwater chemistry dataset from wells was compiled to study groundwater salinization in these aquifers. Waters are mainly of the Na–Cl type, presenting a slightly acidic to slightly alkaline character, with a pH between 5.63 and 8.50 (median 7.40). Electrical conductivity measurements range from 127 to 9,670 μS/cm (median 862), suggesting highly variable mineralization, with higher values observed on Santa Maria, São Miguel, Pico, Graciosa, and São Jorge islands. The major-ion composition reflects the contribution of seawater to the groundwater compositional evolution, which is essentially explained by seawater intrusion into wells. In many samples, exchange reactions of Na⁺ + K⁺ for Ca²⁺ + Mg²⁺ are associated with salinization. The seawater fraction in groundwater composition reaches a maximum of 22.5%. These results are extremely challenging to water managers in the Azores because failure to comply with national water quality regulations and with European Union groundwater directive requirements often occurs.