Chris Conwell was awarded a 2021 Graduate Student Grant Award from the Evolving Earth Foundation to investigate the cause of global cooling leading to the end-Ordovician glaciation. Chris’ proposed work will measure the strontium (⁸⁷Sr/⁸⁶Sr) and neodymium (ε_Nd(t)) isotopic composition of conodonts from Middle–Late Ordovician strata of central and southern Sweden. During this time interval, the collision of volcanic island-arcs with the western margin of Baltica (modern Sweden) likely placed ophiolites onto the continental margin, creating a province of mafic rock susceptible to chemical weathering. Chris’ ⁸⁷Sr/⁸⁶Sr and ε_Nd(t) measurements will evaluate changes in continental weathering lithology through this interval, possibly revealing periods of enhanced mafic weathering which may have contributed to CO_{2 ­}drawdown leading to end-Ordovician glaciation. This work, paired with similar measurements Chris has made on coeval strata on Laurentia (modern North America) that are currently in review for publication, is one of the few existing investigations of the weathering–climate connection in the geologic record, and will contribute to our understanding of long-term drivers of global climate.