Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA.
Science. 2011 Apr 1;332(6025):84-8. doi: 10.1126/science.1198401.
Glacial erosion of mountain ranges produces spectacular alpine landscapes and, by linking climate with tectonics, influences a broad array of geophysical phenomena. Although the resultant landforms are easily identified, the timing and spatial pattern of topographic adjustment to Pleistocene glaciations remain poorly known. We investigated topographic evolution in the archetypal glacial landscape of Fiordland, New Zealand, using (U-Th)/He thermochronometry. We find that erosion during the past 2 million years removed the entire pre-Pleistocene landscape and fundamentally reshaped the topography. Erosion focused on steep valley segments and propagated from trunk valleys toward the heads of drainage basins, a behavior expected if subglacial erosion rate depends on ice sliding velocity. The Fiordland landscape illustrates complex effects of climate on Earth's surface morphology.
山脉的冰川侵蚀造就了壮观的高山景观，并通过将气候与构造联系起来，影响了广泛的地球物理现象。尽管由此产生的地貌很容易识别，但地形对更新世冰川作用的调整时间和空间模式仍知之甚少。我们使用（U-Th）/He 热年代测定法研究了新西兰峡湾地区的典型冰川地貌的地形演化。我们发现，在过去的 200 万年里，侵蚀作用已经完全抹去了整个更新世以前的地貌，并从根本上重塑了地形。侵蚀集中在陡峭的河谷段，并从干流河谷向流域的源头扩展，这种行为如果冰川下的侵蚀速率取决于冰的滑动速度，那么是可以预期的。峡湾地貌说明了气候对地球表面形态的复杂影响。
