Publication Date:
2015-11-21
Description:
The Cenozoic East African Rift System (EARS) extends from the Red Sea to Mozambique. Here we
use seismic reflection and bathymetric data to investigate the tectonic evolution of the offshore branch of the
EARS. The data indicate multiple and time transgressive neotectonic deformations along ~800km of the
continental margin of northern Mozambique. We observe a transition from a mature rift basin in the north to
a juvenile fault zone in the south. The respective timing of deformation is derived from detailed seismic
stratigraphy. In the north, a ~30km wide and more than 150km long, N-S striking symmetric graben initiated
as half-graben in the late Miocene. Extension accelerated in the Pliocene, causing a continuous conjugate
border fault and symmetric rift graben. Coevally, the rift started to propagate southward, which resulted in a
present-day ~30km wide half-graben, approximately 200km farther south. Since the Pleistocene, the rift
has continued to propagate another ~300km, where the incipient rift is reflected by subrecent small-scale
normal faulting. Estimates of the overall brittle extension of the matured rift range between 5 and 12km, with
an along-strike southward decrease of the extension rate. The offshore portion of the EARS evolves magma
poor, similar to the onshore western branch. The structural evolution of the offshore EARS is suggested to
be related to and controlled by differing inherited lithospheric fabrics. Preexisting fabrics may not only guide
and focus extension but also control rift architecture.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
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