Mg. Abdelsalam et al., DEFORMATIONAL HISTORY OF THE NEOPROTEROZOIC KERAF ZONE IN NE SUDAN, REVEALED BY SHUTTLE IMAGING RADAR, The Journal of geology, 103(5), 1995, pp. 475-491
The location of the boundary between juvenile Neoproterozoic crust of
the Arabian-Nubian Shield in the Red Sea Hills and older crust of the
Nile craton to the west is defined by the Keraf zone in northern Sudan
, but little is known about its deformation history. Shuttle Imaging R
adar (SIR-A), Landsat Thematic Mapper (TM), and Large Format Camera (L
FC) images, combined with ground investigation, were used to carry out
the first detailed study of the Keraf zone. This N-trending zone is s
imilar to 45 km wide and is defined by multiply deformed carbonate-ric
h turbidites and volcanogenic sediments. Six deformational phases (D1
to D6) were identified, associated with two tectonic events: (1) D1 an
d D2 are related to emplacement of SSE-verging ophiolitic nappes due t
o collision between the Halfa and Bayuda terranes along the ENE-trendi
ng Atmur suture at similar to 800-700 Ma. The Atmur suture marks the s
ite of a former Neoproterozoic oceanic re-entrant that extended WSW fr
om the Mozambique ocean into the interior of the Nile craton. D1 produ
ced SSE-verging tight folds and thrusts, whereas D2 deformed the D1-st
ructures into ENE-trending upright folds. (2) D3 to D6 reflect shorten
ing across the Keraf zone. D3 produced N-trending, upright, isoclinal
to open folds. D4 was superimposed on D3 as coaxial W-verging tight fo
lds. D5 refolded older structures about steeply, east- to ENE-plunging
fold axes. D6 manifests development of local NE-trending dextral and
NW-trending sinistral shear zones. We suggest that this deformation re
flects oblique collision between composite are terranes of the Arabian
-Nubian Shield and the Nile craton along the Keraf zone at similar to
750-650 Ma.