SPP2 Project - Switching pro- and retro-wedges in the Eastern Alps and their peripheral basins - clues to a change in subduction polarity?

SPP2 项目 - 东阿尔卑斯山及其周边盆地的前楔和后楔的转换 - 俯冲极性变化的线索？

• 批准号: 442568283
• 负责人: Dr. Klaus Bauer
• 金额: --
• 依托单位: Institut für Geologische Wissenschaften
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/442568283?language=en
• 关键词: SPP2; Project; Switching; pro; retro

This project will meet the challenge of determining whether or not a Neogene switch in subduction polarity occurred beneath the Eastern Alps. Further, it will answer the question of how Neogene motion of the indenting Adriatic plate was transferred to the Alpine orogenic crust and will identify the interactions between indentation, slab motions and the dynamics of the Molasse and Veneto (eastern Po) Basins, respectively, north and south of the Alpine Orogen.This will be done by using the structure and basin histories of the Alpine orogen as proxies for subduction polarity. Such a switch is predicted to effect change in the behaviour of the northern orogenic front from pro-wedge type (episodic advance by alternating in- and out-of-sequence thrusting) to retro-wedge type (slower advance, alternating in-sequence thrusting and stagnation). This contrasting behavior is expected to be reflected in the amount and nature of clastic deposits in the Molasse Basin. The transition of the northern Alpine front from pro- to retro-wedge behavior is arguably manifested by stagnation of the thrust front at ~21 Ma during prolonged subsidence of the eastern Molasse Basin until ~16 Ma. Along the southern Alpine front, retro-wedge behaviour may have changed to pro-wedge behaviour with the onset of Neogene thrusting and deformation of proximal parts of the Veneto Basin at 21-22 Ma. The project combines 3 work packages using state-of-the-art seismology, basin analysis and structural geology. The seismological work package will (re)process seismic reflection data from the TRANSALP experiment using cutting-edge techniques. Multi-dimensional coherence analysis will drastically reduce noise and improve subsurface reconstructions with a clearer definition of geologically relevant signatures. The basin analysis work package will use industry seismics and borehole data to reconstruct the structural of the northern orogenic front, the Tertiary subsidence history of the eastern Molasse Basin along and across its strike, and variations in sedimentation patterns next to the orogenic front. The structural geology work package will use these new images as well as those emerging from the EASI and SWATH-D experiments to construct and tectonically balance new integrated geological-geophysical cross sections reaching from the Molasse Basin through the basement core of the Eastern Alps to the Veneto Basin in the south. Deliverables include (1) a 3D high-resolution image of faults beneath the Tauern Window area that partitioned strain during Adriatic indentation and lateral escape; (2) a 4D model of the eastern Molasse Basin that documents advances and retreats of thrusting along the orogenic front, from the Central-Eastern Alps transition in the west to the Alps-Carpathians junction in the east; (3) an integrated 4D model of the Eastern Alps, from slab tearing and breakoff to Adriatic indentation.

这个项目将满足的挑战，以确定是否在俯冲极性发生在东阿尔卑斯山下的新近纪开关。此外，它将回答的问题，新近纪的运动的缩进亚得里亚海板块是如何转移到阿尔卑斯造山地壳，并将确定压痕，板运动和动力学之间的相互作用的Molasse和韦内托（东部波河）盆地，分别在阿尔卑斯造山带的北部和南部，这将通过使用的结构和盆地历史的阿尔卑斯造山带作为代理俯冲极性。预计这种转换将影响北方造山前缘的行为从前楔型（通过交替的序列内和序列外逆冲作用的幕式推进）到后楔型（缓慢推进，交替的序列内逆冲作用和停滞）的变化。预计这种对比行为将反映在磨拉石盆地碎屑沉积物的数量和性质上。北方阿尔卑斯山前缘从亲楔型向后楔型的转变可以通过逆冲前缘在约21 Ma的停滞来证明，在东部磨拉石盆地的长期沉降过程中，逆冲前缘一直停滞到约16 Ma。沿着南部阿尔卑斯山前，后楔行为可能已经改变为前楔行为的开始，在21-22 Ma的韦内托盆地的近端部分的上第三纪逆冲和变形。该项目结合了3个工作包，使用最先进的地震学，盆地分析和结构地质学。地震学工作包将使用尖端技术对TRANSALP实验的地震反射数据进行（重新）处理。多维相干分析将大大减少噪音，并通过更清晰地定义地质相关特征来改善地下重建。盆地分析工作包将利用工业地震和钻孔数据重建北方造山前缘的结构、东部磨拉石盆地沿着和横跨其走向的第三纪沉降历史以及造山前缘附近沉积模式的变化。结构地质学工作包将利用这些新的图像以及EASI和SWATH-D实验中出现的图像，构建并在构造上平衡从磨拉石盆地通过东阿尔卑斯山脉基底核心到南部韦内托盆地的新的综合地质-地球物理横截面。可提供的资料包括：（1）陶恩窗区域下方断层的3D高分辨率图像，该断层在亚得里亚海凹陷和侧向逃逸期间划分了应变;（2）东部磨拉石盆地的4D模型，该模型记录了沿着造山前缘（从西部的阿尔卑斯山脉中东部过渡到东部的阿尔卑斯山脉-喀尔巴阡山脉交界处）逆冲作用的推进和后退;（3）东阿尔卑斯山脉的综合4D模型，从板块撕裂和断裂到亚得里亚海压痕。