The Miocene (23 to 6 million years ago) is a lengthy geological period during which the Earth experienced extreme changes in climate. Atmospheric carbon dioxide during the Miocene was at times similar to near-future climate predictions making the Miocene an important topic of study in order to enable future climate predictions in the context of Anthropogenic climate change. It is also during the Miocene that the Mediterranean Sea began to take shape as Africa and Arabia pushed north and closed up the Eastern Seaway that connected the Mediterranean to the Indian Ocean.
The Maltese Islands consist mostly of marine sediment, large parts of which formed during the Miocene. The location and the excellent nature of the geochemical signature embedded in Maltese sediment makes the Maltese Islands an ideal site for investigating the evolution of global and regional climate during the Miocene.
During his PhD studies at The School of Earth and Environmental Sciences, Cardiff University, Dr Ray Zammit used a combination of high-resolution fieldwork and cutting-edge laboratory geochemical analysis to investigate climate change in the Central Mediterranean during the Miocene. Dr Zammit was able to generate temperature and salinity records and carbon-cycle parameters of Mediterranean sea-water during the Miocene using the Inductively-coupled plasma multicollector mass-spectrometer at the CELTIC (Cardiff Environmental Laboratory for Trace Element and Isotope Chemistry) laboratory facilities at Cardiff University. This was achieved by combined measurement of a host of stable and unstable isotope signatures as well as trace metal records.
These records provide strong evidence for periods of intense precipitation over Western Sahara during the Miocene. The two main humid periods occurred around 20 million and 14 million years ago and lasted for about 1 million years each, with rainfall patterns being driven by astronomical forcing (Milankovitch cycles). Intriguingly, through his studies Dr Zammit has shown that these episodes of high precipitation over Western Sahara follow the closure of the Eastern Mediterranean Seaway, suggesting a link between plate tectonics and climate.
Ray Zammit is a visiting Lecturer at the Faculties of Education, Science and Engineering at the University of Malta.
This PhD study was supervised by Prof. Caroline Lear (Cardiff), Prof. Paul Pearson (Cardiff) and Prof. Aaron Micallef (Malta). Additional support and collaboration was provided by Dr. Or Bialik (Munster), Prof. Lucas Lourens (Utrecht) and Prof. Elias Samankassou (Geneva).
This work was partly funded by the ENDEAVOUR Scholarships Scheme (Group B) National Funds Malta. And partly funded by Cardiff University Match Funding scheme.
