As part of his sabbatical activities, Dr Geraint Owen spent three weeks in May in the Colarado Plateau region of Utah, Arizona and Colorado, undertaking geological fieldwork with Gerald Bryant of Dixie State College, Utah. They were studying the processes responsible for very large-scale contortions (soft-sediment deformation) in the Navajo Sandstone of early Jurassic age. The Navajo Sandstone was deposited about 200 million years ago and represents wind-blown sand dunes that formed in one of the largest ergs (desert sand seas) in the Earth’s history. Much of the cross-bedded sandstone is highly contorted by deformation that occurred soon after the dunes formed, but the processes that drove deformation are unclear. The superb exposures of the Colorado Plateau allow deformed zones to be traced laterally for many hundreds of metres and the gentle dip of the bedding allows their occurrence through the rock succession to be determined. Geraint and Gerald mapped out several zones of deformation in 3 dimensions in order to clarify their geometry and stratigraphical occurrence, and determine whether their formation was related to internal processes such as groundwater movements or inherent instability of the dunes, or to external triggers such as climatic change, earthquakes or even meteorite impacts. They plan to present initial results of their research at the International Sedimentological Congress in Mendoza, Argentina, in September.
Geraint Owen and Gerald Bryant also made initial plans to develop a programme of undergraduate exchange with Dixie State College, through which Swansea students taking the BSc in Physical Earth Science will have the opportunity to undertake geological fieldwork in the Colorado Plateau for their final-year dissertation projects.
In June, also as part of his sabbatical activities, Geraint Owen spent 8 days visiting the Geology Department at the University of Bari, Italy, working with Dr Massimo Moretti. They spent several days in the field studying examples of soft-sediment deformation structures in Mesozoic rocks, and Geraint gave a seminar to staff and students of the department, entitled “Reconstructing desert environments”.