NHM EARTH SCIENCES SEMINAR
Unravelling global warming through soil mineralogy: A case study from a proglacial valley in the Swiss Alps
Dr Christian Mavris, Marie Curie Fellow (ES, NHM)
Tuesday 10th February - 4.00 pm
Earth Sciences Seminar Room (Basement, WEB 05, the previous Mineralogy Seminar Room)
Investigations in Alpine soils indicate that mineral weathering is much faster in ‘young’ soils (<1000 yr) than in ‘old’ soils (∼10,000 yr). However, little is known about the initial stages of weathering and soil formation, i.e. during the first decades of soil genesis. Due to the continuous retreat of the Morteratsch glacier (Upper Engadine, Swiss Alps), the proglacial area offers a full time sequence from 0 to 150 yr old surfaces. The area is well documented regarding vegetation and soils.
The glacial till has an acidic character (granitoid parent rock). Mineralogical measurements were carried out using a broad range of analytical approaches, from XRD to wet chemistry to cathodoluminescence and Nomarski DIC microscopy. Specifically, cathodoluminescence and Nomarski DIC microscopy were used for the first time on minerals involved into an early pedogenic process.
This work clearly demonstrates that in cryic, ice-free environments, chemical weathering rates are high, leading to the formation and transformation of minerals. This clearly influences pedogenic processes to a remarkable extent – and thus, is linked to the settlement of life in previously deglaciated (and extreme) areas.
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