Research statement
Earth’s climate significantly cooled since 2-3 Ma and experienced periodic glaciations that saw the expansion of mid-latitude alpine glaciers. Glacial processes such as abrasion and plucking are suggested to be the primary erosion mechanisms in Alpine valley incision. However, the linkages between climate and (glacial) erosion are still debated mainly because of a lack of geochronological methods that cover the time span of 103-106 years. While conventional thermochronometers like (U-Th-He) in apatite can constrain timescales of 106 years, and cosmogenic nuclide (CN) dating can constrain timescales of 101-103 years, it remains difficult to resolve changes in erosion rates at the timescale of glacial/interglacial cycles. Optically stimulated luminescence (OSL) and electron spin resonance (ESR) thermochronometry have the potential to span this temporal gap, allowing erosion rate changes to be calculated at these timescales.
PhD Project
My PhD project focuses on the impact of Quaternary glaciation on rates of erosion and timing of Alpine valley incision in the western European Alps, which were intensively glaciated during the Quaternary period. This area is characterized by low uplift rates making any competing tectonic effects on rock cooling histories relatively minor. Thus, it is an ideal place to investigate the relationship between glacial erosion rates and mountain landscape evolution.
To estimate rates of erosion, we will develop electron spin resonance (ESR) thermochronometry to constrain the timescale of 103-106 years. We will combine the ESR thermochronometry data together with OSL thermochronometry and detrital cosmogenic nuclide dating to cover the timespan of 101-104 years. Using numerical modelling, I will then try to identify the local glacial incision history and resolve the temporal variation of erosion rates between glacial/interglacial cycles during the late Pleistocene.
Biography
After receiving my bachelor’s degree at Central China Normal University in 2017, I completed my master’s thesis titled ‘Cosmogenic Nuclide 10Be Exposure Dating of the Older Moraine from Yingpu Valley, Northern Queer Mountain’ at South China Normal University. During the project, I participated in an expedition to the southeast of the Tibetan Plateau, and collected and prepared samples for OSL and TCN dating from glaciofluvial terraces and moraines. I also conducted numerical modelling of glacial landscapes. Following this work, I have been captivated by landscape evolution and geochronology. Combining with my previous expertise and interests, I joined the Institute of Earth Surface Dynamics in May 2021 to start my PhD. I look forward to doing research in this field and my adventure in Switzerland.
Contact
Xiaoxia Wen
University of Lausanne
Institute of Earth Surface Dynamics
Géopolis, office 3151
1015 Lausanne, Switzerland
+41 (0)21 692 35 43
xiaoxia.wen@unil.ch