scholarly journals Metallogenic fingerprint of a metasomatized lithospheric mantle feeding gold endowment in the western Mediterranean basin

2021 ◽  
Author(s):  
Erwin Schettino ◽  
Claudio Marchesi ◽  
José María González-Jiménez ◽  
Edward Saunders ◽  
Károly Hidas ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Major Elements ◽  
Western Mediterranean ◽  
Mantle Metasomatism ◽  
Spinel Peridotite ◽  
Western Mediterranean Basin ◽  
Wide Variability ◽  
Geochemical Fingerprint ◽  
Platinum Group ◽  
Slab Tearing

Spinel peridotite xenoliths (one plagioclase-bearing) hosted in alkaline basalts from Tallante (southeast Spain) record the mineralogical and geochemical fingerprint of the subcontinental lithospheric mantle (SCLM) evolution beneath the southern Iberian margin. Mantle metasomatism in fertile lherzolites caused the crystallization of clinopyroxene + orthopyroxene + spinel clusters through the percolation of Miocene subalkaline melts during the westward migration of the subduction front in the western Mediterranean. In the Pliocene, heat and volatiles provided by alkaline host-magmas triggered very low melting degrees of metasomatic pyroxene-spinel assemblages, producing melt quenched to silicate glass and reactive spongy coronae around clinopyroxene and spinel. Refertilization of the Tallante peridotites induced the precipitation of base-metal sulfides (BMS) included in metasomatic clino- and orthopyroxene. These sulfides consist of pentlandite ± chalcopyrite ± bornite aggregates with homogeneous composition in terms of major elements (Ni, Fe, Cu) and semi-metals (Se, As, Te, Sb, Bi), but with wide variability of platinum-group elements (PGE) fractionation (0.14 < PdN/IrN < 30.74). Heterogeneous PGE signatures, as well as the presence of euhedral Pt-Pd-Sn-rich platinum-group minerals (PGM) and/or Au-particles within BMS, cannot be explained by conventional models of chalcophile partitioning from sulfide melt. Alternatively, we suggest that they reflect the incorporation of distinct populations of BMS, PGM, and metal nanoparticles (especially of Pt, Pd, and Au) during mantle melting and/or melt percolation. Therefore, we conclude that Miocene subalkaline melts released by asthenosphere upwelling upon slab tearing of the Iberian continental margin effectively stored metals in metasomatized domains of this sector of the SCLM. Remarkably high Au concentrations in Tallante BMS (median 1.78 ppm) support that these metasomatized domains provided a fertile source of metals, especially gold, for the ore-productive Miocene magmatism of the westernmost Mediterranean.

Sulfide-scale insights into platinum-group element behavior during carbonate mantle metasomatism and evolution of Spitsbergen lithospheric mantle

Lithos ◽  
2016 ◽  
Vol 246-247 ◽  
pp. 182-196 ◽  
Author(s):  
Nak Kyu Kim ◽  
Sung Hi Choi ◽  
Christopher W. Dale
Keyword(s):  
Lithospheric Mantle ◽  
Platinum Group Element ◽  
Mantle Metasomatism ◽  
Group Element ◽  
Platinum Group

Late stage of the Gibraltar arc subduction system (western Mediterranean): from slab-tearing to continental-edge delamination

2020 ◽  
Author(s):  
Ana M. Negredo ◽  
Flor de Lis Mancilla ◽  
Carlos Clemente ◽  
Jose Morales ◽  
Javier Fullea
Keyword(s):  
Sierra Nevada ◽  
Lithospheric Mantle ◽  
Lower Crust ◽  
Receiver Functions ◽  
Western Mediterranean ◽  
Evolutionary Stage ◽  
Edge Delamination ◽  
Slab Tearing ◽  
Subduction System ◽  
Iberian Margin

<p>The Gibraltar arc subduction system is the result of the fast westward roll-back of the Alboran slab at the westernmost end of the Mediterranean Sea. This westward motion is controlled, at its northern edge, by slab tearing along a so called STEP (Subduction-Transform-Edge-Propagator) fault under the Betics orogen. The Alboran subduction process is in its last evolutionary stage, where the oceanic lithosphere has been fully consumed and the continental lithosphere attached to it collides with the overriding plate. In this situation the continued slow convergence between Iberia and Africa could lead to a short stage of continental subduction. However, the particular setup after slab tearing, characterized by a sharp lateral contrast between the orogenic Betic lithosphere and the adjacent thinned lithosphere of the overriding Alboran domain, is also prone to trigger continental delamination, i.e. the detachment between the crust and the lithospheric mantle. Several lines of evidence indicate that northwards mantle delamination is likely occurring in the central Betics. The fast average topographic uplift during the last 8 Ma together with the lack of spatial correspondence between the highest topography (Sierra Nevada Mountains) and the thickest crust indicate that the topography could be partly supported by asthenospheric upwelling due to continental delamination. In this study we take advantage of an unprecedented resolution seismic receiver functions lithospheric mapping in the Betic orogen to investigate the conditions for, and consequences of, edge delamination in the Iberian margin after slab tearing. We show that given a weak enough Iberian lower crust the delaminated lithospheric mantle peels off the crust and adopts a geometry consistent with the imaged southward dipping Iberian lithosphere in the central Betics. In contrast, the thinned lower crust beneath the Iberian margin in the eastern Betics prevented mantle delamination via asthenospheric inflow into the lower crust.</p>

Arcobleu, an integrated surveillance system for chronic and accidental pollution

1995 ◽  
Vol 32 (9-10) ◽  
pp. 25-31
Author(s):  
D. Sauzade ◽  
Y. Hénocque ◽  
A. H. Carof
Keyword(s):  
Surveillance System ◽  
Marine Pollution ◽  
Western Mediterranean ◽  
Private Companies ◽  
Information Tools ◽  
Western Mediterranean Basin ◽  
System Requirement ◽  
Future Extension ◽  
Tools And Techniques ◽  
Preliminary Phase

An integrated surveillance system for chronic and accidental marine pollution is proposed to improve decision making. This project, called ARCOBLEU, is based on organizing advanced communication and information tools and techniques in a multi-source / multi-user architecture. A Franco-Italian consortium associating private companies and public research institutes has already received the support of the EEC MAST program to carry out the preliminary phase of the system requirement, by using the high Tyrrhenean sea as a pilot zone. Future extension to the Western Mediterranean basin is already planned under the name of MED-ARCOBLEU.

scholarly journals Gm and Km alleles in two Spanish Pyrenean populations (Andorra and Pallars Sobira): a review of Gm variation in the Western Mediterranean basin

2001 ◽  
Vol 65 (6) ◽  
pp. 537-548 ◽  
Author(s):  
M. P. GIRALDO ◽  
E. ESTEBAN ◽  
M. P. ALUJA ◽  
R. M. NOGUES ◽  
CH. BACKES-DURO ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Western Mediterranean ◽  
Western Mediterranean Basin

scholarly journals Algerian Olive Germplasm and Its Relationships with the Central-Western Mediterranean Varieties Contributes to Clarify Cultivated Olive Diversification

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 678
Author(s):  
Kamel Atrouz ◽  
Ratiba Bousba ◽  
Francesco Paolo Marra ◽  
Annalisa Marchese ◽  
Francesca Luisa Conforti ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Genetic Relationships ◽  
Olive Tree ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Central Mediterranean ◽  
Western Mediterranean Basin ◽  
New Information ◽  
Mediterranean History ◽  
New Synonymy

Olive tree with its main final product, olive oil, is an important element of Mediterranean history, considered the emblematic fruit of a civilization. Despite its wide diffusion and economic and cultural importance, its evolutionary and phylogenetic history is still difficult to clarify. As part of the Mediterranean basin, Algeria was indicated as a secondary diversification center. However, genetic characterization studies from Maghreb area, are currently underrepresented. In this context, we characterized 119 endemic Algerian accessions by using 12 microsatellite markers with the main goal to evaluate the genetic diversity and population structure. In order to provide new insights about the history of olive diversification events in the Central-Western Mediterranean basin, we included and analyzed a sample of 103 Italian accessions from Sicily and, a set of molecular profiles of cultivars from the Central-Western Mediterranean area. The phylogenetic investigation let us to evaluate genetic relationships among Central-Mediterranean basin olive germplasm, highlight new synonymy cases to support the importance of vegetative propagation in the cultivated olive diffusion and consolidate the hypothesis of more recent admixture events occurrence. This work provided new information about Algerian germplasm biodiversity and contributed to clarify olive diversification process.

scholarly journals Potential deployment of offshore bottom pressure gauges and adoption of data assimilation for tsunami warning system in the western Mediterranean Sea

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohammad Heidarzadeh ◽  
Yuchen Wang ◽  
Kenji Satake ◽  
Iyan E. Mulia
Keyword(s):  
Data Assimilation ◽  
Warning System ◽  
Western Mediterranean ◽  
Tsunami Warning ◽  
Sensitivity Analyses ◽  
Bottom Pressure ◽  
Tsunami Warning System ◽  
Earthquake Scenarios ◽  
The North ◽  
Western Mediterranean Basin

AbstractWestern Mediterranean Basin (WMB) is among tsunamigenic zones with numerous historical records of tsunami damage and deaths. Most recently, a moderate tsunami on 21 May 2003 offshore Algeria, North Africa, was a fresh call for strengthening tsunami warning capabilities in this enclosed water basin. Here, we propose to deploy offshore bottom pressure gauges (OBPGs) and to adopt the framework of a tsunami data assimilation (TDA) approach for providing timely tsunami forecasts. We demonstrate the potential enhancement of the tsunami warning system through the case study of the 2003 Algeria tsunami. Four scenarios of OBPG arrangements involving 10, 5, 3 and 2 gauges are considered. The offshore gauges are located at distances of 120–300 km from the North African coast. The warning lead times are 20, 30, 48 and 55 min for four points of interest considered in this study: Ibiza, Palma, Sant Antoni and Barcelona, respectively. The forecast accuracies are in the range of 69–85% for the four OBPG scenarios revealing acceptable accuracies for tsunami warnings. We conclude that installation of OBPGs in the WMB can be helpful for providing successful and timely tsunami forecasts. We note that the OBPG scenarios proposed in this study are applicable only for the case of the 2003 Algeria tsunami. Further studies including sensitivity analyses (e.g., number of OBPG stations; earthquake magnitude, strike, epicenter) are required in order to determine OBPG arrangements that could be useful for various earthquake scenarios in the WMB.

Variability of Mediterranean aerosols properties at three regional background sites in the western Mediterranean Basin

2014 ◽  
Author(s):  
Michaël Sicard ◽  
Julien Totems ◽  
Rubén Barragan ◽  
François Dulac ◽  
Marc Mallet ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Western Mediterranean ◽  
Regional Background ◽  
Western Mediterranean Basin

IV.—Titaniferous Volcanic Rocks

1907 ◽  
Vol 4 (4) ◽  
pp. 157-165 ◽  
Author(s):  
T. Crook
Keyword(s):  
Mediterranean Basin ◽  
Volcanic Rocks ◽  
Western Mediterranean ◽  
Geological Society ◽  
Western Mediterranean Basin

In a paper read recently at a meeting of the Geological Society, Dr. Washington proposes to treat certain basalts of the Western Mediterranean basin as constituting “a hitherto unrecognised petro-graphic province, or comagmatic region, one of the most salient characters of which is the presence of salfemanes (basalts) that contain remarkably high amounts of titanium.”

The valid nomen for the tree frog (genus Hyla) of Tunisia and Eastern Algeria

Zootaxa ◽  
2020 ◽  
Vol 4759 (4) ◽  
pp. 597-599 ◽  
Author(s):  
CHRISTOPHE DUFRESNES ◽  
PIERRE-ANDRÉ CROCHET
Keyword(s):  
Mediterranean Basin ◽  
Western Mediterranean ◽  
Northern Italy ◽  
Tree Frog ◽  
Rad Sequencing ◽  
Western Mediterranean Basin ◽  
Genome Wide ◽  
Genome Wide Data ◽  
Tree Frogs ◽  
Eastern Algeria

Mediterranean tree frogs, Hyla gr. meridionalis Boettger, 1874 (Anura: Hylidae) are widespread around the Western Mediterranean Basin, where they naturally occur across the Maghreb (Morocco, Algeria, Tunisia). Individuals of diverse Moroccan origins have been introduced and have expanded throughout the Iberian Peninsula, southern France and northern Italy (Liguria), but also on the Canary and Balearic archipelagos (Recuero et al. 2007; Dufresnes et al. 2019). Early molecular studies uncovered several mitochondrial lineages and suggested a major cryptic diversification within this taxon, with Tunisian and eastern Algerian (Numidia) populations carrying deeply divergent haplotypes compared with the rest of the range (Recuero et al. 2007; Stöck et al. 2008; Stöck et al. 2012). While intron markers showed little differentiation (Stöck et al. 2008; Stöck et al. 2012), genome-wide data obtained from RAD-sequencing have supported the deep split suspected from mtDNA (Dufresnes et al. 2018). 

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