Consequence from Craton breakup, ancient rock memory drives kinematics in the Albertine rift, East Africa

Dear colleagues,

The BRS group is excited to welcome you to a seminar presentation given by Daniel Koehn from the University of Glasgow sponsored by VISTA. Daniel will shed light on the complex tectonics of an active continental rift, the East African Rift System.

When: Tuesday, 6.10., 12:15-13:00
Where: Kontinentalsokkelrommet (2G16e, 2nd floor)

Best regards,
The BRS group

Title:
Consequence from Craton breakup, ancient rock memory drives kinematics in the Albertine rift, East Africa

Abstract:
The East African Rift System (EARS) has intrigued scientists for decades as it is the archetype of a continental rift. The Albertine rift system represents the northernmost part of the western branch and is situated in the west of Uganda at the border to the Democratic Republic of Congo. This rift system contains the Rwenzori mountains, a 5000m high basement block that lies within the rift and also represents the edge of the Congo Craton with a thick-skinned fold and thrust belt. This Paleoproterozoic Buganda-Toro belt is relatively stiff and crosses the NNE-SSW running rift system exactly at the node where the highest peaks of the Rwenzori mountains are situated and where the lake George rift terminates towards the north. 
The role of ductile and brittle rift faults in this system is discussed with respect to reactivation, seismic activity and fluid flow. Micro-plate capturing during successive rift propagation leads to capturing of plates and their rotation leading to complex strike-slip and inversion systems on top of the overall extension. It is also shown that the orientation of brittle and ductile fabrics show some similarities indicating that the cross-cutting Buganda-Toro belt influenced rift propagation and brittle fault development within the Rwenzori mountain and that this stiff belt may form part of the reason why the Rwenzori mountains are relatively high within the rift. Numerical modeling of horst uplift confirms this idea and indicates that a stiff horst changes the wavelength of necking in the lithosphere from a two rift and horst to a one-rift system with a high Moho. Uplift of the horst in this case is continuous with rift extension over the last 12 Ma, unless extension rates change significantly over time. The findings are discussed in view of variable uplift models including young fast uplift as well as future research. 

Bio: 
Daniel studied Geology in Karlsruhe (Germany) and Cork (Ireland) before he did his PhD under the supervision of Cees Passchier in Mainz. He then moved to Oslo to work on fluid rock interactions at the Center for Advanced Studies and the University of Oslo. He returned to Mainz to do his Habilitation before becoming a permanent member of staff at the University of Glasgow where he is currently Reader. His main interest is fracturing, reactions, faulting and fluid rock interactions mainly in the upper crust and stress inversion, faulting and uplift in rifts, continental margins and fold and thrust belts.

Daniel is visiting the department from the 5th October to 8th October. If you would like to meet him, just drop Eric (eric.salomon@uib.no) an email.