Evolution and architecture of the Hellenic Arc - Cyprus Arc junction in the eastern Mediterranean

地中海东部希腊弧-塞浦路斯弧交汇处的演变和建筑

• 批准号: 387003-2010
• 负责人: Aksu, Ali
• 金额: $ 7.29万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Ship Time
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=464017
• 关键词: Evolution; architecture; Hellenic; Arc; Cyprus

This study aims to investigate the tectonic and sedimentary evolution of the Hellenic Arc-Cyprus Arc junction in the eastern Mediterranean Sea over the last 25 million years using high-resolution marine multi-channel seismic reflection profiles. The two arcs form the active convergent boundary between the African and Aegean-Anatolian plates. The Hellenic Arc is still an active subduction zone, rolling back to the south, while the subducting African plate dips down below it to the north. The Cyprus Arc is moving much more slowly southwards relative to the African plate. This part of the plate boundary is in transition from subduction to continental collision. Thus, the Hellenic Arc is moving southwards relative to the Cyprus Arc, with the relative motion accommodated by a sinistral transform, which is the focus of this study. The key question is "how do such arc junctions behave? We know they are sites of extreme topography, presumably caused by stress build up at corners. But, the tectonic evolution and its impact on the record of sediments deposited at sea is not well understood. The study area includes the southern portion of the Rhodes Basin, the Anaximander Mountains and the western portion of the Florence Rise. It is the most accessible place to answer these questions, with good knowledge of surrounding geology. The marine areas provide outstanding subsurface seismic images that enable our group to examine the tectonic and sedimentary evolution and determine and the changes in stress orientations during the last 25 million years associated with plate convergence. Our group will test various hypotheses related to the development of extreme relief at the arc-arc junction (Rhodes Basin and Anaximander Mountains), the transfer of thick crustal blocks (Anaximander Mountains) from lower to upper plate as plate convergence proceeds, the behavior of salt in compressional basins (Florence Rise, Antalya Basin), and the timing of dewatering in accretionary wedges (Mediterranean Ridge, Florence Rise) as their stress systems change from compression to transtension.

本研究旨在利用高分辨率海洋多道地震反射剖面研究过去 2500 万年来地中海东部希腊弧-塞浦路斯弧交界处的构造和沉积演化。这两条弧线形成了非洲板块和爱琴海-安纳托利亚板块之间活跃的会聚边界。希腊弧仍然是一个活跃的俯冲带，向南滚动，而俯冲的非洲板块则向北倾斜到其下方。相对于非洲板块，塞浦路斯弧向南移动的速度要慢得多。这部分板块边界正处于从俯冲到大陆碰撞的过渡阶段。因此，希腊弧相对于塞浦路斯弧向南移动，相对运动通过左旋变换来调节，这是本研究的重点。关键问题是“这样的弧形交界处如何表现？我们知道它们是极端地形的地点，可能是由拐角处积聚的应力造成的。但是，构造演化及其对海上沉积物记录的影响尚不清楚研究区域包括罗德盆地的南部、阿那克西曼德山脉和佛罗伦萨海隆的西部，是回答这些问题最容易的地方，对周围的地质区域提供了出色的了解。地下地震图像使我们的小组能够检查构造和沉积演化，并确定过去 2500 万年来与板块汇聚相关的应力方向的变化。我们的小组将测试与弧形极端地形发展相关的各种假设。弧形交界处（罗德盆地和阿那克西曼德山脉），随着板块收敛的进行，厚地壳块（阿那克西曼德山脉）从下板块到上板块的转移，挤压盆地中盐的行为（佛罗伦萨）安塔利亚盆地海隆），以及增生楔（地中海海脊、佛罗伦萨海隆）的脱水时间，因为它们的应力系统从压缩变为张拉。