Detection of Cryptotephra in Sedimentary Profiles Using Reflectance Spectroscopy

In this webinar Spectral Evolution hosted our guest speaker Henry Crawford, PhD Candidate – Geological Sciences | Hyperspectral Earth Observation from the University of British Columbia-Vancouver, British Columbia, Canada for a webinar on the detection of cryptotephra in sedimentary profiles using reflectance spectroscopy.

Explosive volcanic eruptions often blanket landscapes with tephra deposits that, if found, serve as valuable geochronological markers for landforms and sedimentary archives. However, fine-grained tephra (ash) layers are commonly obscured and go undetected, especially when ash fallout from smaller or more distant eruptions is thin, or where tephra has been mixed into host sediments by post-depositional reworking. Detecting these invisible trace tephras, termed ‘cryptotephra’, can greatly expand the scope of tephrochronology in geomorphological and stratigraphic investigations. This work demonstrates mixing experiments as a viable approach for quantifying ash in sediments; a technique potentially transferable to other minerals and applications.