On this location you can find a outcrop which is 6-7m high and 20-30m in lenght. This rock unit consists of several small beds which are approximately 5-15 cm in thickness. These beds are either white or red in color where the red layers have a higher clay content and are structurally less competent. The incompetent red beds show degradation by erosion, while the white beds are more competent and stick out from the wall.
Genisis:
During the separation of the old continent "Gondwana" in the late Carboniferous (318-300 Ma) to Early Permian (300-270 Ma), the Batain Basin opened along the northeastern Oman margin. The continental margin was locally uplifted in the Late Jurassic (160-145 Ma) , which occurred at the same time as the shoreline retreated. Following these events these Sediments became predominant in the Batain Basin due to a reduced bicarbonate influx. The sediments in this outcrop belong to these radiolarites (Sediment made of fossils with silicon) and were deposited below the calcite compensation depth (CCD-line). That means that all calcite will be disolved and only silicon will be depostited. The Formation mainly comprises siliceous sediments, in this case ribbon cherts, which were deposited in chert sequences, which consist of radiolarian cherts with interbeds of siliceous clay material. Research suggests these layers were deposited either in quiet waters far away from the coast or in a protected environment near the coast. At the time of the Cretaceous (145-65 Ma) to Tertiary (65-2 Ma) transition, west-northwest directed shortening led to the closure of the Batain Basin as well as to the detachment of the Batain Basin from the continental slope, which resulted in the formation of the Batain nappes. These were thrust upon the eastern Oman margin and heavily deformed during the obduction (collision and overlaying of tectonic plates) . It has to be noted, that the obduction of the Batain nappes occurred approximately 15-20 million years after the obduction of the Samail Ophiolite. During the Tertiary (65-2 Ma), tectonic processes following the collision of the Arabian with the Eurasian plate such as the opening of the Red Sea and the Gulf of Aden, affected the obducted nappes by shortening processes and resulted in faults as can be seen in the present outcrop.
Questions:
1. In which environment the sediment were deposited??
2. Which two special geological structures can you see, and which one is the older one??
3. Touch the different layers and try to explain why one layer is more white and the other one more red??
4. What do you think, how fast is the deposition rate of this sediment in the environment ??
5. Take your compass and measure in which direction is the dipping of the banks ??
Would be optimal if you could take a photo of yourself infront of the outcrop.
Please send an E-Mail with the answeres to my profile or to: the-mother-of-all-outcrops@gmx.de
References/Referencias
University of Greifswald, GUtech Muscat: Geological filed trip to Oman 2011
IMMENHAUSER, A. et al. (2000): Late Paleozoic to Neogene geodynamic evolution of the northeastern Oman margin – Geol. Mag. 137, pp. 1 – 18