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Shear-wave velocity structure beneath the Dinarides from the inversion of Rayleigh-wave dispersion
Earth and Planetary Science Letters ( IF 4.8 ) Pub Date : 2021-02-01 , DOI: 10.1016/j.epsl.2020.116686
Tena Belinić , Petr Kolínský , Josip Stipčević

Abstract The interaction between the Adriatic microplate (Adria) and Eurasia is the main driving factor in the central Mediterranean tectonics. Their interplay has shaped the geodynamics of the whole region and formed several mountain belts including Alps, Dinarides and Apennines. Among these, Dinarides are the least investigated and little is known about the underlying geodynamic processes. There are numerous open questions about the current state of interaction between Adria and Eurasia under the Dinaric domain. One of the most interesting is the nature of lithospheric underthrusting of Adriatic plate, e.g. length of the slab or varying slab disposition along the orogen. Previous investigations have found a low-velocity zone in the uppermost mantle under the northern-central Dinarides which was interpreted as a slab gap. Conversely, several newer studies have indicated the presence of the continuous slab under the Dinarides with no trace of the low velocity zone. Thus, to investigate the Dinaric mantle structure further, we use regional-to-teleseismic surface-wave records from 98 seismic stations in the wider Dinarides region to create a 3D shear-wave velocity model. More precisely, a two-station method is used to extract Rayleigh-wave phase velocity while tomography and 1D inversion of the phase velocity are employed to map the depth dependent shear-wave velocity. Resulting velocity model reveals a robust high-velocity anomaly present under the whole Dinarides, reaching the depths of 160 km in the north to more than 200 km under southern Dinarides. These results do not agree with most of the previous investigations and show continuous underthrusting of the Adriatic lithosphere under Europe along the whole Dinaric region. The geometry of the down-going slab varies from the deeper slab in the north and south to the shallower underthrusting in the center. On-top of both north and south slabs there is a low-velocity wedge indicating lithospheric delamination which could explain the 200 km deep high-velocity body existing under the southern Dinarides.

中文翻译:

从瑞利波色散反演看第纳尔底德下的横波速度结构

摘要 亚得里亚海微板块(亚德里亚)与欧亚大陆的相互作用是地中海中部构造的主要驱动因素。它们的相互作用塑造了整个地区的地球动力学,并形成了包括阿尔卑斯山、第纳尔山脉和亚平宁山脉在内的几条山带。其中,Dinarides 的研究最少,对潜在的地球动力学过程知之甚少。关于 Dinaric 域下亚德里亚和欧亚大陆之间的当前互动状态,有许多悬而未决的问题。最有趣的一个是亚得里亚海板块岩石圈下冲的性质,例如板块的长度或沿造山带变化的板块配置。先前的调查在第纳尔中北部的最上层地幔中发现了一个低速带,被解释为板块间隙。反过来,几项较新的研究表明,在第纳尔迪斯底下存在连续板片,没有低速带的痕迹。因此,为了进一步研究 Dinaric 地幔结构,我们使用来自更广泛的 Dinarides 地区 98 个地震台站的区域到远震面波记录来创建 3D 横波速度模型。更准确地说,两站方法用于提取瑞利波相速度,而层析成像和相速度的一维反演用于绘制依赖于深度的横波速度。由此产生的速度模型揭示了整个第纳尔迪斯底下存在强大的高速异常,从北部的 160 公里深处到第纳尔底德南部的 200 多公里深处。这些结果与之前的大多数调查结果不一致,并表明欧洲下的亚得里亚海岩石圈沿着整个 Dinaric 地区的持续下冲。下行板坯的几何形状从北部和南部的较深板坯到中心较浅的下冲断层不等。在南北板块顶部都有一个低速楔形,表明岩石圈分层,这可以解释第纳尔迪斯南部下方存在 200 公里深的高速体。
更新日期:2021-02-01
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