Julius Pesola

Tentative project title

Tracing the FLUX of cosmic dust arriving to Earth during the Phanerozoic

Project description

Particles 2mm across, termed micrometeorites, account for most extraterrestrial material arriving to the Earth. The extraterrestrial flux to the Earth has likely changed over time as cosmic dust is produced episodically by asteroid collisions or from comets. Direct study of fossil micrometeorites preserved in sedimentary rocks provides a new method of studying the extraterrestrial flux, complementing existing chemical (e.g. ³He) and physical (e.g. spinel-group minerals) tracers. The broader ERC-CoG FLUX project, which includes this PhD project, aims to extract fossil micrometeorites from c. 25 time intervals across the Phanerozoic to quantify the extraterrestrial flux over time, and constrain the sources cosmic dust and its effects on the Earth. A multi-parameter approach incorporating both novel fossil micrometeorite data and existing tracers will be applied to robustly identify deviations in the extraterrestrial flux. Subsets of fossil micrometeorites will have their O and Fe isotopic compositions measured to deduce the source bodies and regions of cosmic dust, and to use fossil micrometeorites as a past climate proxy. Finally, variability in the extraterrestrial flux will be correlated to asteroid family-forming events in the solar system and to changes in the eccentricity of the Earth’s orbit. Analytical approaches to be employed include optical microscopy, SEM-EDS, μXRF, Raman spectroscopy, EPMA, LA-ICP-MS, and SIMS.

Education

• MSc Earth Science (Earth Structure and Dynamics) – Utrecht University (2024)
• BSc Honours Geology – The University of Edinburgh (2022)

Supervisor

Prof. Dr. Steven Goderis