DEFORMATIONAL HISTORY OF THE NEOPROTEROZOIC KERAF ZONE IN NE SUDAN, REVEALED BY SHUTTLE IMAGING RADAR

Citation
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
Citations number
43
Categorie Soggetti
Geology
Journal title
ISSN journal
00221376
Volume
103
Issue
5
Year of publication
1995
Pages
475 - 491
Database
ISI
SICI code
0022-1376(1995)103:5<475:DHOTNK>2.0.ZU;2-G
Abstract
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.