Arabian-Nubian Shield
The Arabian-Nubian Shield (ANS) is an exposure of
The ANS was the site of some of man's earliest geologic efforts, principally by the
Pharonic Egyptians also quarried granite near Aswan and floated this down the Nile to be used as facing for the pyramids. The Greek name for Aswan, Syene; is the type locality for the igneous rock syenite. The Romans followed this tradition and had many quarries especially in the northern part of the Eastern Desert of Egypt where porphyry and granite were mined and shaped for shipment.
Precious and industrial metals, including gold, silver, copper, zinc, tin, and lead, have been mined in Saudi Arabia for at least 5,000 years. The most productive mine in Saudi Arabia, Mahd adh Dhahab ("Cradle of Gold"), has been periodically exploited for its mineral wealth for hundreds or even thousands of years and is reputed to be the original source of King Solomon's legendary gold. Today, mining at Mahd adh Dhahab is conducted by the Saudi Arabian Mining Company, Ma'aden. Deposits of iron, tungsten, mineral sands, copper and phosphates have been found in many locations. Mining in the Eastern Desert of Egypt and Sudan is limited due to a shortage of water and infrastructure.
Development of the Arabian-Nubian Shield
The Arabian-Nubian Shield (ANS) is the northern half of a great collision zone called the
The shield is divided into crustal blocks or
Key amalgamation events, starting 780–760 Ma, with the formation of the Tabalah–Tarj Shear Zone, the gneiss Afaf Belt, and the 600 km (370 mi) long and 565 km (351 mi) wide Bi'r Umq and Nakasib Suture (780–760 Ma), an ophiolite-decorated fold-shear zone, between the Jiddah–Haya and Hijaz–Gebeit Terranes. Then between 750 and 660 Ma, the Atmur–Delgo Suture formed as Halfa Terrane ophiolite nappes were thrust onto the Bayuda Terrane. Simultaneously, the Allaqi–Heiani–Sol and Hamed–Onib–Yanbu Suture formed, consisting of nappes and portions of ophiolite along an east-trending shear zone between the Gebeit–Hijaz and Eastern Desert Terrane and Midyan Terranes. Between 680 and 640 Ma, the 600 km (370 mi) long and 5–30 km (3–19 mi) wide Hulayfah–Ad-Dafinah–Ruwah Suture formed between the Afif Terrance and terranes to the southwest. Simultaneously, the Halaban Suture formed between the Afif and Ad-Dawadimi Terranes as a nappe of Halaban ophiolite thrust westward. In addition, the Al-Amar Suture, consisting of the Al-Amar Fault zone with ophiolite lenses, between the Ad-Dawadimi and Ar-Rayan Terranes, while the Nabitah Fault Zone formed in Asir Terrane. The final amalgamation event occurred 650–600 Ma, when the Keraf Suture, consisting of ophiolite folded and sheared rocks, formed between the Bayuda–Halfa and GebeitGabgaba Terranes.[1]
Post-amalgamation events include the formation of the Huqf
A number of features have been ascribed to late stage
Crustal weaknesses before 500 Ma influenced
Gold deposits in Egypt and Nubian Sudan
As Rosemarie and Dietrich Klemm point out, "...gold deposits exploited in antiquity occur almost exclusively in the Neoproterozoic sequences of the ANS in the Eastern Desert in Egypt and Northern Sudan." The shield in this part of Africa consists of a cratonic African basement or "infrastructure", overlain by a pan-African
Wadi el-Sid was the chief mining area for the
The well of Umm el-Fawakhir area includes a Large Ptolemaic settlement and round stone mills dating from the Roman or Early Arab Period to the oval stone mills of the New Kingdom. Even fist hammers from the Old/Middle Kingdom are present. Tailings were reworked by the Louison Company from the 1930s until 1956.[4]: 140–141, 146
Volcanogenic massive sulfide ore deposit external links
- Hamama VMS deposit in Egypt
- Bisha VMS deposit in Eritrea
- Hassai VMS deposit in Northern Sudan
- Jabal Sayid VMS deposit in Saudi Arabia
See also
References
- ^ a b c d e Johnson, Peter; Woldehaimanot, Beraki (2003). Yohida, M.; Windley, B.F.; Dasgupta, S. (eds.). Development of the Arabian-Nubian Shield: perspectives on accretion and deformation in the northern East African Orogen and the assembly of Gondwana, in Proterozoic East Gondwana: Supercontinent Assembly and Breakup, Geological Society Special Publication No. 206. London: The Geological Society. pp. 289–325.
- ^ Blasband, B., White, S., Brooijmans, P., De Boorder, H. & Visser, W. 2000. Late Proterozoic extensional collapse in the Arabian-Nubian Shield. Journal of the Geological Society, 157, 615–628. "Archived copy" (PDF). Archived from the original (PDF) on 2008-12-19. Retrieved 2008-04-14.
{{cite web}}
: CS1 maint: archived copy as title (link) - ^ Lindquist, Sandra (1998). The Red Sea Basin Province: Sudr Nubia(!) and Maqna(!) Petroleum Systems, USGS Open-File Report 99-50-A (PDF). US Dept. of the Interior. p. 5.
- ^ ISBN 9783642225079.
Further reading
- B. E. Abulnaga, 2010. 'Slurry Pipelines for Egypt and Sudan'. Mining Engineering. Society of Mining Engineers, March 2010 pp. 20–26.
- Barrie, C. T., Nielsen, F. W., and Aussant, C., 2007, The Bisha volcanic-associated massive sulfide deposit, Western Eritrea: Economic Geology, v. 102, pp. 717–738.
External links
- The Eastern Desert of Egypt in Ancient Times Archived 2012-08-13 at the Wayback Machine
- The Petra Archeological Park; Petra was carved into lower Paleozoic sandstone.
- Geology of Saudi Arabia
- USGS pamphlet on gold, including early mining in Egypt and Arabia
- Website for the Saudi Geological Survey, which does a lot of work on the Arabian-Nubian Shield.
- UNESCO World Heritage site for St. Catherine monastery area. This is built upon ANS exposures in Sinai.