P. O. Koons

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The mechanics and petrological signature of a collisional mountain belt can be significantly influenced by topographic and erosional effects at the scale of large river gorges. The geomorphic influence on crustal scale processes arises from the effects of both stress localization due to existing topography, and also erosional removal of advected crustal(More)
High-grade gneisses (amphibolite–granulite facies) of the Namche Barwa and Gyala Peri massifs, in the eastern Himalayan syntaxis, have been unroofed from metamorphic depths in the late Tertiary–Recent. Rapid exhumation (2–5 mm year)1) has resulted in a pronounced shallow conductive thermal anomaly beneath the massifs and the intervening Tsangpo gorge. The(More)
  • 2002
The Nanga Parbat Massif is located in northwestern Pakistan and occurs in the interior of the western syntaxis of the Himalaya. Recent studies have shown that the massif exposes an active metamorphic anomaly developed in Indian-Plate rocks exhumed from beneath and surrounded by rocks of the Kohistan/Ladakh island-arc. Geochemical and geophysical data from(More)
Crevasse initiation is linked to strain rates that range over three orders of magnitude (0.001 and 0.163 a –1) as a result of the temperature-dependent nonlinear rheological properties of ice and from water and debris inclusions. Here we discuss a small cold glacier that contains buried crevasses at and near an ice divide. Surface-conformable stratigraphy,(More)
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