An Erosion Rate For Everest

Prosjektbeskrivelse

The Himalaya are a tectonically active, glacierised mountain range where landscape evolution is strongly influenced by Quaternary climate change. However, across much of the Himalaya, including the Everest region, few data currently exist that constrain variability in the rates of Quaternary denudation. Studies of Quaternary denudation rates in the Central Himalaya using terrestrial Be-10 surface exposure-age dating to represent rockwall erosion over centennial to millennial timescales generally show a positive relationships between denudation and elevation (e.g., Olen et al., 2015). However, the available data are few and give conflicting results; Last Glacial to late Holocene bedrock erosion in the Everest region was estimated as 3.9 mm a−1 (Barnard et al., 2006), much higher than the catchment-wide rates estimated by previous work (e.g., Hornsey et al., 2022). The location and intensity of headwall erosion is known to vary
with air temperature, and so climate, in the Everest region (Scherler, 2014). However, no study to date has attempted to measure how headwall erosion has varied with elevation and over time scales representative of individual glaciations. The aim of this project is to prepare and analyse rock samples from the headwalls of Khumbu Glacier collected from between 5,100–5,300 m above sea level to determine current and palaeo-erosion rates using combined Be-10 cosmogenic-nuclide exposure-age dating and luminescence rock-surface exposure-age dating methods (Lehmann et al. 2020). These data will fill an important knowledge gap in current models of Quaternary glacial landscape evolution in the Central Himalaya, and could be used by the student to further develop and apply current glacier evolution models to represent the impacts of variable Holocene erosion rates on glacier change.

Research questions

• How have headwall erosion rates varied through the Holocene in the Everest region?
• Do headwall erosion rates vary with elevation, and hence climate, over time?
• What are the impacts of deglaciation on headwall erosion rates and sediment delivery to glacier surfaces?

Proposed course plan during the master's degree (60 ECTS)

GEOV230: Glacial geology and geomorphology (10 sp)
SDG207: Energy Transition (5p)
GEOV336: Field and Laboratory Course in Quaternary Geology (10p)
GEOV322: Master Level Field Excursion in Quaternary Geology (5 sp)
GEOV302: Data analysis in earth science (10p),
GEOV316: Practical Skills in Remote Sensing and Spatial analysis (10p)
GEOV329: Quaternary Geochronology (10 sp)

Prerequisites

The project will require laboratory work for luminescence measurements at the University of Lausanne in Switzerland, and the use of scripted programming languages (MATLAB/Python) for data analysis and visualisation of results. Familiarity with these methods is useful but not essential, as training and ongoing support will be provided. The student may have the opportunity to take part in fieldwork in the Himalaya to become familiar with the glacial landscapes in this region.

External data

None

Field-, lab- and analysis work

Laboratory work for luminescence measurements at the University of Lausanne in Switzerland