Surface morphology of active normal faults in hard rock: Implications for the mechanics of the Asal Rift, Djibouti

Details Surface morphology of active normal faults in hard rock: Implications for the mechanics of the Asal Rift, Djibouti Surface morphology of active normal faults in hard rock: Implications for the mechanics of the Asal Rift, Djibouti

Oct 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010e%26psl.299..169p&link_type=abstract

Earth and Planetary Science Letters, Volume 299, Issue 1-2, p. 169-179.

Computer Science

Scientific paper

Tectonic-stretching models have been previously proposed to explain the process of continental break-up through the example of the Asal Rift, Djibouti, one of the few places where the early stages of seafloor spreading can be observed. In these models, deformation is distributed starting at the base of a shallow seismogenic zone, in which sub-vertical normal faults are responsible for subsidence whereas cracks accommodate extension. Alternative models suggest that extension results from localised magma intrusion, with normal faults accommodating extension and subsidence only above the maximum reach of the magma column. In these magmatic rifting models, or so-called magmatic intrusion models, normal faults have dips of 45-55° and root into dikes. Vertical profiles of normal fault scarps from levelling campaign in the Asal Rift, where normal faults seem sub-vertical at surface level, have been analysed to discuss the creation and evolution of normal faults in massive fractured rocks (basalt lava flows), using mechanical and kinematics concepts. We show that the studied normal fault planes actually have an average dip ranging between 45° and 65° and are characterised by an irregular stepped form. We suggest that these normal fault scarps correspond to sub-vertical en echelon structures, and that, at greater depth, these scarps combine and give birth to dipping normal faults. The results of our analysis are compatible with the magmatic intrusion models instead of tectonic-stretching models. The geometry of faulting between the Fieale volcano and Lake Asal in the Asal Rift can be simply related to the depth of diking, which in turn can be related to magma supply. This new view supports the magmatic intrusion model of early stages of continental breaking.

Affiliated with

Also associated with

No associations

Rating

Surface morphology of active normal faults in hard rock: Implications for the mechanics of the Asal Rift, Djibouti does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Surface morphology of active normal faults in hard rock: Implications for the mechanics of the Asal Rift, Djibouti, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface morphology of active normal faults in hard rock: Implications for the mechanics of the Asal Rift, Djibouti will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1230763