Collaborative Research: PICASSO: Program to Investigate Convective Alboran Sea System Overturn

阿尔沃兰海是在新第三纪非洲和欧洲汇合期间席卷西地中海的年轻俯冲带之后形成的。 直布罗陀弧和阿尔沃兰海是该系统的最西端，也是最令人困惑的部分之一。 向西回滚、伸展、走滑、火山作用、隆起和沉降的混合体，使试图组成一个一致的情景来解释所有观测结果的努力落空了。 部分由于数据不足，已经提出了许多模型，涉及俯冲，板片断裂，分层和滴。 有可信的证据表明，西向俯冲带的覆盖板块的岩石圈地幔已经被弧后拉伸和某种类型的对流去除（如滴，分层等）减薄。 对流变薄的过程知之甚少，但被认为是重要的驱动隆起和沉降的地球？的表面，影响在活动造山带的变形率，并有助于回收大陆材料回到地幔。 该合同规定对阿尔沃兰海、直布罗陀弧、阿特拉斯山脉和地中海西部周边地区进行多学科国际调查，使用被动和主动地震学、大地电磁学、地球化学、岩石学/结构地质学和地球动力学建模。 该项目的总体目标是研究造成阿尔韦塔尔-阿尔沃兰海区域对流变薄的过程。 该项目被称为PICASSO，目前已在西班牙和爱尔兰获得资助，作为欧盟-美国合作项目，其他一些欧盟国家已提交或正在提交提案。 该项目被选为欧洲地形的试点实验，欧洲地形是欧洲科学基金会最近批准的一项类似地球观测的举措。 大部分的实地部署将由欧洲科学家完成，包括一个3D EarthScope型滚动阵列（IberArray），以及由美国调查人员进行的其他有针对性的实地实验。 IberArray已经在PICASSO现场区域部署了约60个站点。

The Alboran Sea was created in the wake of the young subduction zones that swept across the Western Mediterranean in the Neogene during the convergence of Africa and Europe. The Gibraltar Arc and Alboran Sea are the westernmost part of the system and one of the most confusing. The mixture of westward rollback, extension, strike-slip, volcanism, uplift and subsidence has defied attempts to compose a consistent scenario that explains all of the obervations. Partly as a result of inadequate data, there are many models that have been proposed involving subduction, slab breakoff, delamination and drips. There is credible evidence that the lithospheric mantle of the overriding plate of a west-facing subduction zone has been thinned by both back-arc stretching and some type of convective removal (e.g. drips, delamination, etc.). The process of convective thinning is poorly understood but is believed to be important in driving uplift and subsidence of the Earth?s surface, influencing rates of deformation in active orogens, and contributing to recycling of continental materials back into the mantle. This award provides for a multidisciplinary, international investigation of the Alboran Sea, Gibraltar arc, Atlas Mountains and surrounding areas in the western Mediterranean using passive and active seismology, magnetotellurics, geochemistry, petrology/structural geology, and geodynamic modeling. The overall goal of the project is to study the processes responsible for convective thinning in the Gibraltar-Alboran Sea region. The project, known as PICASSO, has now been funded in Spain and Ireland as a colloaborative EU-US program, with proposals from a number of other EU nations submitted or in process. The project was selected as the pilot experiment for TopoEurope, an EarthScope-like initiative recently approved by the European Science Foundation. A large part of the field deployments will be done by European scientists, including a 3D EarthScope-type rolling array (IberArray), with additional targeted field experiments by US investigators. The IberArray is already underway with ~60 stations deployed in the PICASSO field area.