Shallow high-resolution seismics and reprocessing of industry profiles in southern Bavaria: The Molasse and the northern Alpine front
Shallow high-resolution seismics and reprocessing of industry profiles in southern Bavaria: The Molasse and the northern Alpine front
复制标题
巴伐利亚南部的浅层高分辨率地震和工业概况的再处理：莫拉塞和北部阿尔卑斯山前缘
DOI：
10.1016/j.tecto.2005.10.025
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Fertig
中科院分区：
文献类型：
--
作者：
R. Thomas;K. Schwerd;K. Bram;J. Fertig
作为国际 TRANSALP 项目的一部分，在上巴伐利亚米斯巴赫地区进行的这次地震调查的目的是研究原地前陆磨拉石和标志着阿尔卑斯造山带构造前缘的外来折叠磨拉石之间的构造接触。另一个具体目标是覆盖折叠磨拉石的 Helveticum/Ultrahelveticum 和 Rhenodanubian Flysch 构造单元的锋面新兴主冲断层的倾角。对从碳氢化合物行业获得的十二条地震剖面进行了再处理。从前陆磨拉石向南到逆掩褶皱磨拉石地下的原生磨拉石，可以识别出明显的特征，如磨拉石基底陡峭的正断层、磨拉石沉积物的S向增厚或上海相磨拉石的沉积不一致基底。浅层高分辨率地震测量是沿着前陆磨拉石和折叠磨拉石之间的构造接触面的两个剖面进行的，以及沿着赫尔维蒂库姆/超赫尔维蒂库姆和雷诺达努比亚复理石的锋面新兴主冲断层的剖面进行的。可以在顶部300-500 ms的双向走时区间内识别地质构造，这对于通常的深地震方法来说是很难实现的。因此，该方法在深反射地震学和地表地质学之间架起了一座桥梁。与西巴伐利亚磨拉石带不同，研究区前陆磨拉石和折叠磨拉石之间的构造边界不具有大的盲冲三角带，而是简单的南倾逆冲面。毗邻 S 线的是几个陡峭的南倾逆冲莫拉西冲断层和米斯巴赫向斜。逆冲断层切片被解释为断层传播褶皱的翻转和剪切北翼，在造山运动的最后阶段将折叠磨拉石与前陆磨拉石连接起来。 Helveticum/Ultrahelveticum 和 Rhenodanubian Flysch 的主推力在高分辨率反射地震数据的近地表层段中得到了很好的成像。与之前发表的结果相反，这些推力面显示出从表面到至少 500-1000 米深度的 S 向轻微倾斜。
The purpose of this seismic investigation in the Upper Bavarian Miesbach area, as part of the international TRANSALP project, was to study the tectonic contact between the autochthonous Foreland Molasse and the allochthonous Folded Molasse marking the tectonic front of the Alpine orogen. Another specific target was the dip of the frontal emerging main thrust of the tectonic units Helveticum/Ultrahelveticum and Rhenodanubian Flysch overriding the Folded Molasse. Twelve seismic profiles obtained from the hydrocarbon industry were reprocessed. From the Foreland Molasse southward to the Autochthonous Molasse in the subsurface of the overthrust Folded Molasse conspicuous features such as steep normal faults at the Molasse base, S-directed thickening of Molasse sediments or sedimentary discordant base of Upper Marine Molasse can be recognized. Shallow high-resolution seismic measurements were conducted along two profiles across the tectonic contact between Foreland Molasse and Folded Molasse, as well as along a profile across the frontal emerging main thrust of the Helveticum/Ultrahelveticum and the Rhenodanubian Flysch. Geological structures could be identified in the top 300–500 ms two-way traveltime interval, which is hardly possible with the usual deep-seismic method. The method thus provides a bridge between deep-reflection seismics and surface geology. In contrast to the western Bavarian Molasse zone, the tectonic boundary between the Foreland Molasse and the Folded Molasse in the investigated area is not characterized by a large blind-thrust triangle zone but by a simple south-dipping thrust plane. Adjacent to the S follow several steeply south-dipping inverse Molasse thrust slices and the Miesbach syncline. The inverse thrust slices are interpreted as the overturned and sheared northern limb of a fault propagation fold, which linked the Folded Molasse to the Foreland Molasse during a final orogenic phase. The main thrust of the Helveticum/Ultrahelveticum and the Rhenodanubian Flysch are well imaged in the near-surface interval of the high-resolution reflection seismic data. In contrast to previously published results, these thrust planes show a gentle dip to the S from the surface down to at least 500–1000 m depth.