Examining the Rates and Controls of Erosion and Landsliding in New Zealand with Cosmogenic Nuclides

Duna Roda-Boluda, GFZ German Research Centre for Geosciences

The Southern Alps of New Zealand are known to be one of the fastest-eroding mountain ranges in the world, however the distribution of uplift and erosion, and the processes controlling them remain debated. To examine this, I will first present new 10Be catchment-averaged erosion rates from 20 catchments. Catchment-averaged erosion rates span an order of magnitude, between ~0.8 and >10 mm/yr. Tectonics can explain well the magnitude and general patterns of 10Be erosion rates along the range, but there is significant variability on the 10Be erosion rates that cannot be ascribed to the along-strike Alpine Fault throw patterns. We find that superimposed on the primary tectonic control, there is an elevation/temperature control on erosion rates, which is probably transient and related to frost-cracking and glacial retreat. While most work on tectonic-climate feedbacks has focused on orographic precipitation and glaciation, our results show that temperature-controlled erosion also plays an important role in the interplay of climate and tectonics. Second, I will present preliminary results on how we are using paired in-situ 14C-10Be measurements from recent landslides in New Zealand to infer long-term (102-103) landslide recurrence intervals and show how these measurements offer promise as a tool for tracing erosional depth-provenance, and potentially fingerprinting landslide-derived sediment.

Host: Claire Masteller

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