997 resultados para Western Mediterranean Sea
Resumo:
The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through the marine isotope stages (MIS) 15-1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. Here, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically dated Mediterranean marine and continental proxy records. The alternative age model presented here shows consistent differences with that initially proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this new age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how a detailed study of independent chronological tie points is important to align different records and to highlight asynchronisms of climate events. Moreover, Francke et al. (2016) have incorporated the new chronology proposed for tephra OH-DP-0499 in the final DEEP age model. This has reduced substantially the chronological discrepancies between the DEEP site age model and the model proposed here for the last glacial-interglacial transition.
Resumo:
Compositional and chemical analyses suggest that Middle Triassic–Lower Liassic continental redbeds (in the internal domains of the Betic, Maghrebian, and Apenninic chains) can be considered a regional lithosome marking the Triassic-Jurassic rift-valley stage of Tethyan rifting, which led to the Pangaea breakup and subsequent development of a mosaic of plates and microplates. Sandstones are quartzose to quartzolithic and represent a provenance of continental block and recycled orogen, made up mainly of Paleozoic metasedimentary rocks similar to those underlying the redbeds. Mudrocks display K enrichments; intense paleoweathering under a hot, episodically humid climate with a prolonged dry season; and sediment recycling. Redbeds experienced temperatures in the range of 100°–160°C and lithostatic/tectonic loading of more than 4 km. These redbeds represent an important stratigraphic signature to reconstruct a continental block (Mesomediterranean Microplate) that separated different realms of the western Tethys from Middle-Late Jurassic to Miocene, when it was completely involved in Alpine orogenesis.
Resumo:
In the last decade irregular immigration has emerged as a “security” challenge (in the language of International Relations military “threat”) in the Mediterranean region particularly in the central, sub-region1. The designation of this issue as a “security challenge” or “threat” is itself controversial and will be discussed further down. This paper focuses on the situation in the central Mediterranean involving mainly four countries namely Italy, Libya, Malta and Tunisia all of which have long standing historic links and bilateral relations and participate in the so called “5+5” Dialogue in the Western Mediterranean. Two of these Central Mediterranean countries (Italy, Malta) are EU member states and Tunisia has a long standing relationship with the EU [Association Agreement, Barcelona Process (EMP), Neighbourhood Policy (ENP), Union for the Mediterranean (UfM)] while Libya so far has no formal relations at all with the EU. This paper analyses some of the aspects of migration in the central Mediterranean focusing on the link between the domestic and international politics of the issue in Italy and Malta and contrasting the different approaches taken. For example, although Italy and Malta both resort to self-help and both try to involve the EU in helping them tackle the problem, they do this in a markedly different way: Italy uses the EU as a supplement to its independent and bilateral efforts while Malta looks to the EU as the major solution to the problem. Lacking the power and influence to deal with the issue, Malta tends to see the problem as primarily a multilateral issue or one that can only be tackled in concert with stronger powers in the region preferably within an EU context. On the other hand, Italy has been keen in involving the EU but decided to go it alone when this option turned out to be a dead end. In this paper I also try to show the extent (or limitations) to which multilateral initiatives such as the “5+5” and Euro operation really play a decisive role in incentivizing or facilitating inter-state cooperation or joint solutions. This paper also refers to the EU acquis, the notion of solidarity (norms) and the extent to which it is implemented as well as a number of connected issues. The subjects of this paper, the Mediterranean Boat People, have been referred to by various names in the literature, all of which may be more or less deficient in actually defining them all. They have been referred to as “illegal” or “irregular” immigrants, “refugees” in search of international protection, “migrants at sea” and “boat people”. The use of “boat people” dispenses with the need of having to define the various categories of migrants involved and is thus preferred in this paper.