Dynamics and numerical modeling of deep-seated accretionary prisms in the Chilean Coastal Cordillera

目标：我们的建议集中在智利科迪勒拉海岸的HP/LT岩石上。这代表了收敛边际的短期增长。智利中部保存下来的增生体系显示了超过100 Ma的旋回物质流动，而弧形花岗岩类则显示出稳定的楔形后区。34°S的N和48°S的S的N相似的吸积棱柱被俯冲侵蚀破坏。我们的目标是了解智利化石增生棱柱的形成、俯冲、折返和破坏历史的主要原因，以及与伴生的岩浆弧有关的历史。方法论。我们将(1)利用变形、热和折返历史的约束，通过数值热力学2D模拟来检验当前的概念模型和已获得的PTTD路径；(2)通过在智利中部建立早期时间标志，通过碎屑锆石(U/Pb)和白云母(Ar/Ar)测年，阐明被动-活动大陆边缘的演化；(3)与提供岩石学和地质年代学支持的合作项目合作，研究34°S和48°S的增生棱柱N的不同破坏机制；(4)通过汇编有关智利基底的所有信息，完善构造变质模型。

Objectives: Our proposal focusses on HP/LT rocks along the Coastal Cordillera of Chile. These represent short periods of growth of the convergent margin. Preserved accretionary systems in central Chile reveal cyclic mass flow over ~ 100 Ma, whereas arc granitoids matk stable retrowedge areas. N of 34°S and S of 48°S similar accretionary prisms are destroyed by subduction erosion. Our goal is to understand the principal causes for the formation, subduction, exhumation and destruction histories of fossil Chilean accretionary prisms in relation to concomitant magmatic arcs. Methodology. We will (1) test current conceptual models and acqired PTtd-paths by numerical thermomechanical 2D-modeling with constraints from the deformational, thermal and exhumational histories; (2) elucidate the evolution of passive-to-active continental margins by establishing early time markers in central Chile via detrital zircon (U/Pb) and white mica (Ar/Ar) dating; (3) study the different mechanisms of destruction of accretionary prisms N of 34°S and S of 48°S in cooperation with partner projects providing petrological and geochronological support; (4) to refine tectono-metamorphic models by compiling all information about the Chilean basement.