JEBEL goes to Saudi Arabia – 2012

In November 2012 JEBEL and the Saudi Geological Survey host a 600 km crustal transect across the Saudi Arabian shield involving c. 20 international scientists, post-docs and PhD students. The results from this geotransect will be used to better understand the crustal structure and tectonic evolution of the shield, and will later be integrated with a shallow seismic experiment being organized by geophysicists at Stanford University and ultimately with a deep seismic experiment being organized by the US Geological Survey.    

Follow the blog by Fitsum Girum, an IGV PhD student.
 

The An Nakhil gneiss belt is part of an en-echelon Najd fault system (c. 600Ma), which is one of the major structures in Arabian-Nubian Shield. The supracrustal and plutonic rocks that comprise this belt are strongly deformed and moderately metamorphosed, and hence the name ‘’gneiss belt’’. Strong foliation and lineation are characteristic of this gneiss belt.

A mafic enclave (just beneath the pen) in a porphyritic rock. Mafic enclaves are common features of plutonic rocks and may mark the mingling of mafic and felsic magmas. This enclave is markedly different from the host rock both texturally and compositionally.

The Wajid Sandstone, of Cambro-Ordovician age, rests uncomformably on peneplained Precambrian crystalline basement of the southern Arabian Shield, in this case the Sabya Volcanics. The detrital zircon study of this sandstone by Fitsum Girum is expected to shed light on its provenance.

Day 1

Sheared-up serpentinite and gabbro at Yanbu Suture and this is the southern extension of Jabal Wask Ophiolite. This suture marks the boundary between Hijaz and Midyan terranes.


JEBEL participants having lunch in Arabian desert. The Sun is hammering but we always find a refuge in the shades.


JEBEL scientists posing at the contact between the basement Arabian-Nubian Shield and Permian Khuff Formation. This is where the Shield starts in western Saudi Arabia and we have put our hands right at the contact!

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