The Middle East in the shadow of the Islamic State. OSW Point of View Number 52, August 2015

Since June 2014, Islamic State (IS) has been regarded as the principal security threat in the Middle East and one of the most important problems for European and global security. Islamic State, which for many years was just one of many terror organisations with links to al-Qaeda, has succeeded in achieving much more than other similar organisations: it has taken over control of large swathes of territory in Syria and Iraq by military means, created its own para-state structures in that area, and become the greatest civilisational challenge for the region in a century as it established a self-proclaimed caliphate and credibly pledged to expand further on a global scale. Those successes have been accompanied by widely publicised acts of systemic brutality which meets the definition of crimes against humanity. One outcome of these developments is the emergence of an exotic informal alliance to combatthe Islamic State, which has brought together all the states from the Middle East and many from beyond the region. However, contrary to what could have been predicted, after almost a year of the declared war against IS, the Caliphate still holds most of the ground it gained in 2014.

Thallium concentrations and isotope composition of MORB glasses and altered oceani crust from DSDP/ODP Hole 504B and DSDP Hole 52-417D

Hydrothermal fluids expelled from the seafloor at high and low temperatures play pivotal roles in controlling seawater chemistry. However, the magnitude of the high temperature water flux of mid-ocean ridge axes remains widely disputed and the volume of low temperature vent fluids at ridge flanks is virtually unconstrained. Here, we determine both high and low temperature hydrothermal fluid fluxes using the chemical and isotopic mass balance of the element thallium (Tl) in the ocean crust. Thallium is a unique tracer of ocean floor hydrothermal exchange because of its contrasting behavior during seafloor alteration at low and high temperatures and the distinctive isotopic signatures of fresh and altered MORB and seawater. The calculated high temperature hydrothermal water flux is (0.17-2.93)*10**13 kg/yr with a best estimate of 0.72*10**13 kg/yr. This result suggests that only about 5 to 80% of the heat available at mid-ocean ridge axes from the crystallization and cooling of the freshly formed ocean crust, is released by high temperature black smoker fluids.The residual thermal energy ismost likely lost via conduction and/or through the circulation of intermediate temperature hydrothermal fluids that do not alter the chemical budgets of Tl in the ocean crust. The Tl-based calculations indicate that the low temperature hydrothermal water flux at ridge flanks is (0.2-5.4)*10**17 kg/yr. This implies that the fluids have an average temperature anomaly of only about 0.1 to 3.6 °C relative to ambient seawater. If these low temperatures are correct then both Sr and Mg are expected to be relatively unreactive in ridge-flank hydrothermal systems and this may explain why the extent of basalt alteration that is observed for altered ocean crust appears insufficient to balance the oceanic budgets of 87Sr/86Sr and Mg.

Leyes : número 48, que establece la Junta Central de Conciliación y Arbitraje y las Juntas Municipales de Conciliación : número 52, sobre indemnizaciones por accidentes sufridos en el trabajo : número 67, del trabajo y de la previsión social.

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