Paper Number: 627
UPPER CRETACEOUS-TERTIAY STRIKE-SLIP TECTONICS IN NE LIBYA:
EVOLUTION WITHIN DEXTRAL SPLAY DUPLEX STRUCTURE
El Amawy, M.A.1, Abdelsamad, E.2, Hadiya, F.H.2, Muftah, A.M.2 and Abdelmalek, M.B.2
1Department of Geology, Faculty of Science, Banha University, Egypt.
2Department of the Earth Sciences, Benghazi University, Libya
The structural pattern reflected evolutionary inversion by style of wrenching tectonics proceeded elsewhere via transpression, in response to a dextral compressional shear. It is themed by NE-SW ductile-brittle shear zones that confine a system of E-W to ENE-WSW trending folds, WNW-ESE dextral strike-slip faults (Riedel shears R1), N-S sinistral strike-slip faults (conjugated Riedel shears R2), ENE-WSW minor thrusts and pop up structures, NNW-SSE normal faults, pull apart basins and accompanied joints. Deformation synthesis on the present structures showed four phases of folding (F1, F2, F3 and F4) related to the movement on consistent sequence of faulting during Late Cretaceous-Miocene. F1 to F3 folding phases are formed within and before outlining the spectacular shape of F4 major folds (ex. Jardas Al Abid and Ras El Hilal). These folds are the result of successive tectonic stages initiated by intense and tight folding in Santonian, close folding during Campanian-Maastrichtian then open in Eocene and gentle folding in the Oligocene-Miocene.
Originally, the whole structure revealed a tectonic evolution within splay strike-slip duplex, which played an important role in the development of escarpments along the western part of Al Jabal Al Akhdar.
REFERENCES:
[1] Suleiman, A. S., and Doser, D. I. (1995), Geophys. J. Int., 312-322.
[2] Foder, L., Turkey, S. M., Dalub, H. and Al Gerbi, A. (2005), Terra nova, 121-128
[3] Muftah, A. M., El-Mehaghag, A. A., Ben Shatwan M.S. and Badi, S. M. (2002), International Energy Foundation, Tripoli, 101-112.
[4] El Amawy, M. A., Muftah, A. M.; Abdel Wahed, M. and Nassar, A. (2011), Arabian Journal of Geosciences, http://link.springer.com/journal/12517/4/7/page/1 Issue 7-8, 1067-1085.