Quantifying Tectonic and Glacial Controls on Topography: Patagonia, South America

据推测，冰川侵蚀对山地地形具有一级控制作用。雪线高度和造山带高度之间的全球相关性一般证实了这一假设。然而，与这一趋势存在重大差异。构造对冰川地形的控制构成了一个未被充分认识的强迫因素组合，可能是这些差异的来源，也是本建议的重点。最近的研究表明巴塔哥尼亚安第斯山脉是一个主要的冰川控制地形变化的典型例子。然而，这些地形的变化与一个主要的构造边界，其特点是收敛率下降四倍和洋脊碰撞。在这个修订后的建议，我们评估的假设，纬度地形变化在巴塔哥尼亚安第斯山脉控制气候驱动的梯度在冰川侵蚀效率。此外，我们假设，由于最近的断层驱动的斜脊碰撞内侧的智利三联点的差异岩石隆起与观察到的短波长的地形变化。我们将测量新的基岩热时计数据，这些数据来自于可能与洋脊碰撞有关的位移的断层系统。将从纬度变化的冰川集水区收集碎屑热时计数据，以量化冰川侵蚀的海拔变化。总之，这些新的（和现有的）数据将被用来评估四个端元可测试的结果，辨别构造与冰川控制巴塔哥尼亚地形的短波长变化。

Glacial erosion is hypothesized to exert a first order control on mountain topography. Global correlations between snowline altitudes and orogen hypsometry generally confirm this hypothesis. However, major discrepancies from this trend exist. Tectonic controls on glaciated topography constitute an underappreciated combination of forcing factors that could be the source of these discrepancies and are the focus of this proposal. Recent research suggests the Patagonian Andes are a prime example of a dominant glacial control on variations in topography. However, these topographic variations are associated with a major tectonic boundary characterized by a fourfold drop in convergence rates and oceanic-ridge collision. In this revised proposal, we evaluate the hypothesis that latitudinal topographic variations in the Patagonian Andes are controlled by climate driven gradients in glacial erosion efficiency. Furthermore, we hypothesize that differential rock uplift due to recent faulting driven by oblique ridge collision inboard of the Chilean Triple Junction is linked to observed short-wavelength changes in topography. We will measure new bedrock thermochronometer data from across fault systems with possible displacement linked to oceanic-ridge collision. Detrital thermochronometer data will be collected from latitudinally varying glaciated catchments to quantify elevation dependent variations in glacial erosion. Together, these new (and existing) data will be used to evaluate four end-member testable outcomes that discern the tectonic vs. glacial controls on short wavelength variations in Patagonian topography.