Contrasting deformation styles along an active thrust belt front - the external Dinarides and Hellenides

沿活跃冲断带前缘的对比变形样式 - 外部 Dinarides 和 Hellenides

• 批准号: 269913092
• 负责人: Professor Dr. Klaus Reicherter
• 金额: --
• 依托单位: Lehr- und Forschungsgebiet für Neotektonik und Georisiken (NUG)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/269913092?language=en
• 关键词: Contrasting; deformation; styles; along; active

The fold-and-thrust belt of the Dinarides-Hellenides on the Balkan Peninsula is a rare example of active continental subduction. We propose to study its active tectonics in an area of transient kinematics between southern Croatia, Montenegro and northern Albania. Several anomalous features characterize this area and need clarification: (a) northward-diminishing seismic moment release, (b) northward disappearance of a continental lithospheric slab and (c) northward end of syn-collisional extension related to subduction rollback. The study area hosted numerous historical earthquakes as well as one of the strongest instrumentally recorded earthquakes in Europe (Montenegro 1979, MW 7.1). GPS studies indicate convergence between Adria and Eurasia at rates of 4-5 mm yr-1, largely accommodated within the external thrust belt. Long-term convergence rates, by contrast, remain unconstrained. We aim to characterize the structural basis of this transient kinematic behaviour in a two-fold approach: (1) Balanced cross sections in two regional transects on either sides of the orogen-perpendicular Skutari-Pec Fault, which delimits syn-collisional extension to the north, will allow quantifying the overall Cenozoic crustal shortening as well as the contribution of rollback-triggered extension in the transect south of the Skutari-Pec Fault. (2) Presently active structures will be identified by tectonic geomorphological and paleoseismological studies. Emphasis will be given to quantifying rates of surface uplift and active folding in the adjacent coastal areas by dating Quaternary aggradational river terraces affected by river incision and fold growth. In combination with constraints on geometries of active faults, this will allow estimating fault slip rates on a 10-100 kyr time scale. These slip rate estimates will provide average values across many seismic cycles compared to GPS-derived convergence rates that are valid only for the last 1-2 decades, i.e., a seismically quiet period since the 1979 event. The comparison of long-term and short-term slip rates can potentially highlight locked faults and is hence of relevance for assessing the seismic hazard. Our study will also contribute towards a better understanding of continental subduction and thrust belt propagation in areas characterized by low plate convergence rates.

巴尔干半岛上的迪纳里德斯-赫勒尼德斯褶皱逆冲带是活跃大陆俯冲的罕见例子。我们建议研究克罗地亚南部、黑山和阿尔巴尼亚北部之间瞬态运动学区域的活动构造。该区域有几个异常特征，需要澄清：（a）向北减少的地震矩释放，（b）大陆岩石圈板块向北消失，以及（c）与俯冲回滚相关的同碰撞延伸向北结束。该研究区域发生过多次历史地震，也是欧洲仪器记录的最强地震之一（黑山 1979 年，兆瓦 7.1）。 GPS 研究表明，亚德里亚和欧亚大陆之间的聚合速度为 4-5 mm yr-1，大部分位于外部冲断带内。相比之下，长期收敛速度仍然不受限制。我们的目标是通过双重方法来描述这种瞬态运动行为的结构基础：（1）造山带垂直的斯库塔里-佩克断层两侧的两个区域横断面的平衡横截面，该断面界定了向北的同碰撞延伸，将允许量化整体新生代地壳缩短以及回滚触发的延伸在造山带以南的横断面中的贡献。 斯库塔里-佩克断层。 (2) 目前的活动构造将通过构造地貌学和古地震学研究来识别。将重点通过对受河流切割和褶皱生长影响的第四纪加积河流阶地进行测年来量化邻近沿海地区的地表隆起和活动褶皱的速率。结合活动断层几何形状的限制，这将允许估计 10-100 kyr 时间尺度的断层滑动率。这些滑移率估计值将提供多个地震周期的平均值，而 GPS 得出的收敛率仅在过去 1-20 年有效，即自 1979 年事件以来的地震平静期。长期和短期滑移率的比较可以潜在地突出锁定断层，因此对于评估地震危险具有相关性。我们的研究还将有助于更好地了解板块收敛速度较低的地区的大陆俯冲和冲断带传播。