From October 1 to December 19, 2025, Jester F. Cleope, a graduate student from the Nannoworks Laboratory, completed his osmium isotope analysis and training at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) – Yokosuka Headquarters.
This was a continuation of his previous visit in April 2025 to the University of Tsukuba and the Atmosphere and Ocean Research Institute (AORI) at the University of Tokyo. There, he prepared powdered samples for osmium and carbon isotope analysis under the supervision of his thesis co-adviser, Dr. Maria Luisa G. Tejada, Senior Research Staff at the Volcanology and Geochemistry Research Group, JAMSTEC, and his thesis reader, Dr. Hironao Matsumoto of the University of Tsukuba.
As part of Jester’s thesis, “Calcareous Nannofossil Biostratigraphy and Osmium Isotope Record of the Berriasian to Hauterivian Section of the Umbria-Marche Basin, Italy,” osmium isotope analysis was conducted at JAMSTEC under the supervision of Dr. Maria Luisa G. Tejada. During his stay, multiple limestone samples from the Chiaserna Monte Acuto and Gorgo a Cerbara sections were subjected to Re-Os analysis. The resulting 187Os/188Os ratios serve as a critical proxy for continental versus mantle input, which will be correlated with Ocean Anoxic Events (OAEs) from this interval, specifically the Weissert Event.
These activities are made possible through the support of his Continuous Operational and Outcomes-based Partnership for Excellence in Research and Academic Training Enhancement (COOPERATE) grant, which provides opportunities for advanced research training and international collaboration.
