College Lecturer in Earth Sciences
Brooke Johnson is a geologist researching the co-evolution of early eukaryotic life and Earth surface environments. His work combines classical field geology and petrographic observation, with high resolution geochemical analysis in order to understand the role of the environment in shaping the evolution of early complex life.
Brooke graduated in Geology from Birkbeck College, University of London where his thesis investigated extreme climate change events in the early Jurassic of North Yorkshire, UK. Following graduation Brooke began his DPhil as part of the NERC/Oxford DTP in Environmental Research before moving to Earth Sciences to begin his project investigating the impact of low oxygen levels on early complex life.
Brooke’s primary work focuses on sediments from the Roper Superbasin, an inland sea that covered northern Australia 1.3 billion years ago. Roper sediments are unusually well preserved, despite their great age, and contain both exceptional fossils of early eukaryotes, and the environments in which they lived. By studying these sediments, Brooke is able to reconstruct ancient environmental conditions, and understand the availability of biologically important nutrients, such as phosphorus.
Brooke’s work also investigates the formation of ironstones; sedimentary rocks enriched in iron and an important economic source of this element. Ironstone formation is currently poorly understood with many unanswered questions, such as why ironstone formation is limited to certain intervals in Earth history.
Brooke tutors petrography – the study of rocks in hand specimen and under the microscope – and invertebrate palaeontology. Additionally, Brooke is also a demonstrator on the Earth Sciences department first year field classes to Pembrokeshire and Arran.