Geodynamics and Neotectonic Forearc Deformation: Late Pliocene-Recent Basins, Hellenic Arc (Greece)

9815028Kleinspehn弧前区域显示了广泛的运动学行为，包括弧前区域内部的变形。在全球范围内，弧前平行伸展是最常见的内应变，它可以产生大量的快速弧前隆起。本研究的目的是建立俯冲带动力学与观测到的希腊弧前（希腊）南部和东南部的内部新构造应变之间的关系，作为岩石圈辐合倾角的函数。通过考察从克里特岛（汇合线几乎是正交的）到罗多斯岛（汇合线矢量高度倾斜的）沿弧前走向向东的年轻盆地的运动学记录，我们将探讨有关新构造弧前隆升机制的几种假设：(1)弧平行伸展，(2)径向伸展，(3)缩短，或(4)挤压或张拉作用下的扭扭构造。结合构造制图/运动学分析、构造地层学和年龄关系以及弧前地球动力学的三维建模，将解决随着汇聚倾角的增加，沿弧走向的运动学变化问题。通过对晚上新世—近代盆地的充填进行时间和古地理控制，并记录其沉积后变形模式和邻近的基底运动学，将出现弧前内部的新构造逆构造。量化岩石圈对斜辐合的响应的能力依赖于综合使用4OAr/39Ar地质年代学、磁地层学和盆地生物地层学的定年变形。将研究局限于最年轻的盆地限制了推断运动学的年龄，并将利用沉积盆地固有记录的垂直速度。三维数值模型结果将与观测到的构造地层学和非国家模式进行比较，以将岩石圈地球动力学与观测到的应变联系起来，并将希腊系统与全球其他内部变形的前弧进行比较。拟议的研究将检查陆上构造地层学，这些地层学相当于海上钻井计划中即将针对的海上序列，并将补充目前计划在克里特岛进行的ICDP项目，以评估覆盖板块前缘的力学行为。由于这项研究涉及现代构造，因此它与地震活动、变化的地形和迁移的海洋海岸线对古代和现代地中海文化的影响的考古研究有关。了解弧前岛屿新构造隆升的驱动机制，有助于更准确地评估这些人口稠密岛屿附近的地震危险性。

9815028Kleinspehn Fore-arc regions display a wide range of kinematic behaviors, including deformation internal to the fore-arc. Among fore-arcs globally, arc-parallel extension is the most commonly observed internal strain and it can produce substantial rapid fore-arc uplift. The goal of this study is to establish the relationship between subduction-zone dynamics and observed internal neotectonic strain of the southern and southeastern Hellenic fore-arc (Greece) as a function of the obliquity of lithospheric convergence. By examining the kinematics recorded by young basins along strike in the fore-arc going eastward from Crete, where convergence is nearly orthogonal, to the island of Rhodos where the convergence vector is highly oblique, several alternative hypotheses concerning the mechanisms driving neotectonic fore-arc uplift will be addressed: (1) arc-parallel extension, (2) radial extension, (3) shortening, or (4) wrench tectonics under transpression or transtension. Combined structural mapping/kinematic analyses, tectonostratigraphy, and age relations along with threedimensional modeling of the fore-arc geodynamics will address the changing kinematics along the strike of the arc with increasing obliquity of convergence. By using the fill of Late Pliocene-Recent basins for temporal and paleogeographic control and documenting its synand post-depositional deformation as well as adjacent basement kinematics, the neotectonic defon-nation internal to the fore-arc will emerge. The ability to quantify the lithospheric response to oblique convergence relies on dating deformation using combined 4OAr/39Ar geochronology, magnetostratigraphy and biostratigraphy of the basins. Limiting the study to the youngest basins restricts the age of the inferred kinematics and will capitalize on the vertical velocities inherently recorded by sedimentary basins. Three-dimensional numerical model results will be compared to the observed tectonostratigraphic and defon-national patterns to link lithospheric geodynamics to the observed strain and to compare the Hellenic system to other internally deforming fore-arcs globally. The proposed study will examine onshore tectonostratigraphy equivalent to offshore sequences soon to be targeted during a leg of the Offshore Drilling Program and would complement a currently planned ICDP project on Crete to evaluate the mechanical behavior of the leading edge of the overriding plate. Because this study addresses modem tectonics, it is relevant to archeological studies of the impact of seismicity, changing topography and migrating marine shorelines on ancient and modem Mediterranean cultures. Understanding the mechanisms driving neotectonic uplift of these fore-arc islands may enable more accurate evaluation of seismic hazards in the vicinity of these populated islands.