Quantifying the Effects of Mantle Processes and Climate Variability on HinterlandDenudation in the Central and Eastern Alps since the Oligocene

现今对阿尔卑斯莫霍断层的层析成像发现，在中阿尔卑斯至东阿尔卑斯约135-165公里深的地方，大约沿亚得里亚海边缘方向，有两个残余的地幔岩石圈板块。这一观察结果对渐新世以来欧洲和亚得里亚海板块的地幔过程和地幔岩石圈板块几何形状提出了新的假设。例如，渐新世和早中新世/中中新世发生了板块断裂事件，随后发生了俯冲极性反转。它们对地表过程的潜在影响，即保存在中新世地层记录和现今基岩中的内陆剥蚀，将是本建议的主要重点。我们将利用沿着NFP-20E、TRANSALP和EASI剖面创建的2D运动学场来重建中阿尔卑斯到东阿尔卑斯的3D运动学历史，并将其作为最先进的数值景观演变/地表过程模型（LEMs）的输入。通过测试地幔诱发的地表隆起的幅度和波长范围，再加上这个“基线”3D运动学场，我们将能够通过模拟侵蚀通量、基岩和碎屑热年代数据，量化地幔过程对腹地剥蚀的影响。为了区分地幔效应和气候效应，例如中新世气候优化引起的，我们的LEMs将受到时空变化降水的影响。在包含地幔和气候成分的LEMs中模拟的腹地剥蚀将与现有的现今基岩和中新世地层碎屑热年代学数据进行比较，以评估是否有任何提出的地幔过程导致可观测的地表响应。我们新颖的地幔-地表数值模拟方法不仅在MB-4D SPP的第一阶段继续我们的工作，而且还直接解决了其第二阶段的主题2。

Present-day tomographic mapping of the Alpine Moho identified two remnant mantle lithospheric slabs beneath the Central to Eastern Alps at ca. 135-165 km depth approximately along-strike the Periadriatic Lineament. This observation led to new hypotheses on mantle processes and mantle lithospheric slab geometries of the European and Adriatic plates since initial continental collision during the Oligocene. For example, slab break-off events are being proposed for the Oligocene and Early/Middle Miocene followed by subduction polarity reversal. Their potential influence on surface processes, i.e. hinterland denudation, preserved in the Miocene stratigraphic record and present-day bedrock will be the main focus of this proposal. We will take advantage of 2D kinematic fields created along the NFP-20E, TRANSALP and EASI profiles to reconstruct the 3D kinematic history of the Central to Eastern Alps and use this as input to state-of-the-art numerical landscape evolution / surface processes models (LEMs). By testing a range of magnitudes and wavelengths of mantle-induced surface uplift, added to this ‘baseline’ 3D kinematic field, we will be able to quantify the effect of mantle processes to hinterland denudation through modelling of erosional flux, bedrock and detrital thermochronological data. In order to distinguish mantle and climatic effects caused, for example, by the Miocene Climatic Optimum our LEMs will be subject to spatially and temporally variable precipitation. Hinterland denudation modelled in LEMs that contain both, mantle and climate components, will be compared to existing present-day bedrock and Miocene stratigraphic detrital thermochronologic data to evaluate whether any of the proposed mantle processes resulted in an observable surface response. Our novel mantle-to-surface numerical modelling approach not only continues our work during the first phase of the MB-4D SPP but also directly addresses its second phase Theme 2.