Skip to main content

Preliminary results of a first record of gold and uranium in marble from Central Eastern Desert, Egypt: a witness for (syn- and post-?) metamorphic mineralization in metasediments

نتائج أولية لأول تسجيل للذهب واليورانيوم في صخور الرخام بوسط الصحراء الشرقية، مصر: شواهد على تمعدنات مصاحبة ولاحقة للتحول (؟) بالرسوبيات المتحولة

Abstract

This paper records, for the first time, the mineralization of gold (0.98–2.76 ppm) and uranium (133–640 ppm) in marbles from the Arabian-Nubian Shield of the Eastern Desert of Egypt. These auriferous and uraniferous marbles are hosted by sheared and altered ophiolitic serpentinized ultramafic rocks of Gebel El-Rukham (ER), Wadi Daghbag (DG), and Wadi Al Barramiyah (BM). They occur as massive or banded in pod-like or bedded shapes. The ER and BM-mineralized marbles are impure calcitic, whereas the DG marble is impure calcitic to impure dolomitic. Their protolith are pure limestones and dolomitic limestones with probable argillaceous components (BM marble), and their metamorphism (Pan-African) was retrograde. Peaks of metamorphism were at granulite-amphibolite facies for the ER and BM marbles, forming diopside (Al2O3 = 0.17–1.07 wt.%) at 600–900°C and augite (Al2O3 = 2.45–9.40 wt.%) at 825–975°C, and at the amphibolite facies for DG marble, recrystallising the carbonate minerals and forming tremolite. The lowest temperatures of metamorphism were at the upper subgreenschist facies as chlorite (ER and BM marbles) and kaolinite (DG marble) were formed. Metamorphic fluids were, most probably, essentially binary H2O–CO2 mixtures with low NaCl and HF concentrations. Gold in the studied mineralized marbles occurs as native nuggets (10–35 μm) having globule, rod, crescent, and streak shapes, in pores, vugs, and fissures. The source of gold in all marbles is mostly the country ultramafic rocks. Timing of gold mineralization relative to the marblization and metamorphism of the country source ultramafic rocks was both syn- and post-metamorphic. Concerning the ER and DG marbles, it was syn-metamorphic, where Au liberation and transportation were mostly by the metamorphic fluids. The composition and temperature of these fluids were most probably inappropriate for formation of the sulfide complexes of gold. The gold mineralization of BM marble, on the other hand, was mostly post-metamorphic. The mineralising fluid was of surficial origin under oxidizing conditions. The encountered uranium minerals are of secondary origin such as autunite, uranophane, and carnotite. These minerals occur as fine oval aggregates and irregular grains (10–50 μm) usually filling fissures and vugs. The uranium mineralization can be classified as surficial of ages <1.5 Ma. It is proposed that the U was transported from its source (might be flesite and trachyte dikes for the ER and DG marbles and granite rocks for BM marble) to the marble rocks by surface and/or underground water related to the pluvial periods in Egypt. In BM marble, U and Au have mutual mineralizing fluid but different paragenesis.

يسجل

هذا البحث لأول مرة تمعدنات الذهب واليورانيوم في صخور الرخام المتواجدة ضمن الدرع العربي النوبي بالصحراء الشرقية بمصر. ويتراوح تركيز الذهب في هذه الصخور من 0.98 إلي 2.76 جزء من المليون أما تركيز اليورانيوم فيتراوح من 133 الي 640 جزء من المليون. وتعطي هذه التركيزات مع تواجد معادنها في صورة محررة كما سيذكر لاحقا بالإضافة للانتشار السطحي الواسع لصخور الرخام الحاوية لها إمكانية لتمعدنات اقتصادية كبيرة. وتتواجد صخور الرخام الحاوية للذهب واليورانيوم مع الصخور الفوق مافية المسربنتنة والمتحللة بثلاثة مناطق وهي جبل الرخام ووادي دغبج ووادي البراميه وذلك على شكل كتل أو شرائط طبقية أو أخدودية. وتركيب الرخام الممعدن بمناطق جبل الرخام ووادي دغبج كالسيتي غير نقى أما الرخام الممعدن بوادي البراميه فيتراوح من الكالسيتى الغير نقي إلى الدولوميتي الغير نقي. ويرجع تكوين صخور الرخام موضوع الدراسة لتحول تراجعي لصخور جيرية وجيرية دولوميتية محتوية على مكونات طينية بالأخص صخور وادي البراميه. ووصل التحول بصخور جبل الرخام ووادي البراميه في قمته في سحنة الجرانيولايت-أمفيبولايت حيث تكون الديوبسيد في درجات حرارة من 600 إلي 900 درجة مئوية والأوجيت (والذي يحتوي على أكسيد الومنيوم حتى 9.40 نسبة وزنيه) في درجات حرارة تراوحت من 825 إلي 975 درجة مئوية، أما رخام وادي دغبج فقمة تحوله كانت في سحنة الأمفيبولايت حيث تم إعادة تبلور معادن الكربونات وتكوين للتريمولايت. أما أدنى درجات التحول فكانت في سحنة الشيست الأخضر العلوية حيث يتكون الكلوريت في رخام جبل الرخام والبراميه والكاولينيت في رخام وادي دغبج. وسوائل التحول كانت غالبا خليطا من الماء وثاني أكسيد الكربون مع القليل من كلوريد الصوديوم و فلوريد الهيدروجين.والجدير بالذكر أن معدن الذهب في صخور الرخام يتواجد كشزرات صافية غير مصاحبة لمعادن أخري (أقطارها تتراوح من 10 إلي 35 ميكرون) ذات أشكال كروية، عصوية، هلالية، شرائطية وذلك في مسامها وفجواتها وشقوقها. يعتقد أن مصدر الذهب هو الصخور الفوق مافية المصاحبة لصخور الرخام أما توقيت تحرر الذهب وتمعدنه في رخام جبل الرخام ووادي دغبج فكان مزامنا للتحول في فترة الحمى الأفريقي حيث تحرر الذهب واستقر بصخور الرخام بفعل محاليل التحول. وكانت للحرارة العالية وتركيب هذه المحاليل السبب في أنها لم تسمح بانتقال وترسيب الذهب في متراكبات كبريتيدية. وعلى النقيض فتمعدن الذهب برخام البراميه غالبا حدث بعد عمليات التحول حيث سوائل تمعدن غنية بالأكسجين وذات أصل سطحي.أما معادن اليورانيوم في صخور الرخام والتي تشتمل على الأتونيت، اليورانوفين، الكارنوتيت فهي غالبا ذات أصل ثانوي. تتواجد كتجمعات من حبيبات بيضاوية الشكل أو غير منتظمة ذات أقطار تتراوح من 10 إلي 50 ميكرون بداخل المسام والفجوات والشقوق. وتصنف تمعدنات اليورانيوم بصخور الرخام على أنها سطحية ذات أعمار أقل من 1.5 مليون سنة. ويعتقد أن مصدر اليورانيوم هو قواطع الفلسيت والتراكيت بالنسبة لرخام جبل الرخام ووادي دغبج وصخور الجرانيت لرخام البراميه حيث انتقل اليورانيوم بالماء السطحي أو التحت السطحي المرتبط بالفترات المطيرة بمصر. كما أن معادن اليورانيوم والذهب برخام البراميه تكونت بنفس المحاليل ولكن في صحب مختلفة.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9

References

  • Abu El Ela AM (1985) Geology of Wadi Mubarak District, Eastern Desert, Egypt, Ph.D. Thesis, Tanta University, 359 p (unpublished)

  • Anovits LM, Essene EJ (1987) Phase equilibria in the system CaCO3-MgCO3-FeCO3. J Petrol 28:389–414

    Google Scholar 

  • Botros NS (1995) Genesis of gold mineralization in the North Eastern Desert, Egypt. Ann Geol Surv Egypt 20:381–409

    Google Scholar 

  • Botros NS (2002) Metallogeny of gold in relation to the evolution of the Nubian Shield in Egypt. Ore Geol Rev 19:137–164

    Article  Google Scholar 

  • Botros NS (2004) A new classification of the gold deposits of Egypt. Ore Geol Rev 25:1–37

    Article  Google Scholar 

  • Cathelineau M, Nieva D (1985) A chlorite solid solution geothermometer. The Los Azufres (Mexico geothermal system). Contrib Mineral Petrol 91:235–244

    Article  Google Scholar 

  • Clifford TN (1970) The structural framework of Africa. In: Clifford TN, Gass IG (eds) African magmatism and tectonism. Oliver and Boyd, Edinburgh, pp 1–26

    Google Scholar 

  • Dardir AA, Elshimi KA (1992) Geology and geochemical exploration for gold in the banded iron formation of Um Nar area, Central Eastern Desert, Egypt. Ann Geol Surv Egypt 18:381–409

    Google Scholar 

  • Dickson T (1990) Carbonate mineralogy and chemistry. In: Tucker ME, Wright VP (eds) Carbonate sedimentology. Blackwell Scientific Publications, Oxford, pp

    Google Scholar 

  • El Gaby S, List FK, Tehrani R (1988) Geology, evolution and metallogenesis of the Pan-African Belt in Egypt. In: El Gaby S, Greiling RO (eds) The Pan-African belt of Northeast Africa and Adjacent Area. Braunschweig/Wiesbaden, pp 17-68

  • El Shazly EM, El Kassas IA, El Taher MA (1982) Distribution and orientation of mafic dikes in wadi Abu Zawal area, Eastern Desert. Egypt J Geol 16:95–105

    Google Scholar 

  • El-Aassy IE, Ahmed FY, Afifi SY, El-Shamy AS (2000) Uranium in laterites of south-western Sinai, Egypt. First Seminar on NRM and Their Technology

  • Elevatorski EA (1978) Uranium ores and minerals, 88p, Organized by IAEA

  • El-Kammar AM, El-Kammar MM (2002) On the trace elements composition of the Egyptian phosphates: a new approach. Proceedings of the 6th International Conference on the Geology of the Arab World, Cairo University, Egypt, pp 227-244

  • El-Shibiny NH, Salem IA, Hamdy MM, Abu-Laban SA (2005) Mineralogy, geochemistry and petrogenetic implications of marbles from Sol Hamed Melange, South Eastern Desert, Egypt. Delta J Sci 29:185–211

    Google Scholar 

  • Esmail EM (2005) Subsurface geological constraints controlling uranium mineralization at the northern part of Gabal Gattar, north Eastern Desert, Egypt. Ph.D. Thesis, Ain Shams University, 194 p (unpublished)

  • Finger F, Helmy HM (1998) Composition and total-Pb model ages of monazite from high-grade paragenesis in the Abu Swayel area, south Eastern Desert, Egypt. Mineral Petrol 62:269–289

    Article  Google Scholar 

  • Gao S, Luo T-C, Zhang BR, Zhang HF, Han Y-W, Zhao ZD, Hu YK (1998) Chemical composition of the continental crust as revealed by studies in East China. Geochim Cosmochim Acta 62:1959–1975

    Article  Google Scholar 

  • Glyuk DS, Khlebnikova AA (1982) Gold solubility in water, HCl, HF and sodium and potassium chloride, fluoride, carbonate and bicarbonate solutions at a pressure 1000 kg/cm2. Dokl Akad Nauk SSSR 254:190–194

    Google Scholar 

  • Hamdy MM, Lebda EM (2007) Metamorphism of ultramafic rocks at Gebel Arais and Gebel Malo Grim, Eastern Desert, Egypt: mineralogical and O-H stable isotopic constraints. Egypt J Geol 51:105–124

    Google Scholar 

  • Harraz HZ (2000) A genetic model for a mesothermal Au deposit: evidence from fluid inclusions and stable isotopic studies at El Sid Gold Mine, Eastern Desert, Egypt. J Afr Earth Sci 30:267–282

    Article  Google Scholar 

  • Harraz HZ (2002) Fluid inclusions in the mesothermal gold deposit at Atud mine, Eastern Desert, Egypt. J Afr Earth Sci 35:347–363

    Article  Google Scholar 

  • Helmy HM (2000) Pyrite zoning in the Sukkari gold mine, Eastern Desert, Egypt: a possible mechanism of gold deposition. 13th Annual Meeting of the Mineralogical Society of Egypt (Abstract)

  • Hey MH (1954) A new review of the chlorites. Mineral Mag 30:277

    Article  Google Scholar 

  • IAEA International Atomic Energy Agency (1996) Uranium deposits classification In: IAEA periodically report “Uranium, Resources, Production and Demand”

  • Kamel O, El Mahalallawi M, Niazy E, Helmy H (1998) Geochemistry of Umm Rus gold-quartz veins central Eastern Desert of Egypt. Egypt Mineral 10:31–50

    Google Scholar 

  • Keays RR (1984) Archaean gold deposits and their source rocks: the upper mantle connection. In: Foster RP (ed) Gold 82, the geology, geochemistry and genesis of gold deposits. Balkema, Rotterdam

    Google Scholar 

  • Keays RR, Scott R (1976) Precious metals in ocean ridge basalts as source for gold mineralization. Econ Geol 71:705–720

    Article  Google Scholar 

  • Khalil IK, Helba HA, Mücke A (2003) Genesis of the gold mineralization at the Dungash gold mine area, Eastern Desert, Egypt: a mineralogical-microchemical study. J Afr Earth Sci 37:111–122

    Article  Google Scholar 

  • Korzeb SL (1997) The chemical evolution and paragenesis of uranium minerals from the Ruggles and Palermo granpegmatites, New Hampshire. Can Mineral 35:135–144

    Google Scholar 

  • Kraemer TF, Genereux DP (1998) Applications of uranium- and thorium-series radionuclides in catchment hydrology studies. In: Kendall C, McDonnell J (eds) Isotope tracers in catchment hydrology. Elsevier, Amsterdam

    Google Scholar 

  • Kretz P (1980) Occurrence, mineral chemistry, and metamorphism of Precambrian carbonate rocks in a portion of the Grenville Province. J Petrol 21:573–620

    Google Scholar 

  • Kretz R (1982) A model for distribution of trace elements between calcite and dolomite. Geochim Cosmochim Acta 46:1981–1999

    Google Scholar 

  • Le Bas MJ (1999) Sovite and alvikite: two chemically distinct calciocarbonatites C1 and C2. S Afr J Geol 102:109–121

    Google Scholar 

  • Le Bas MJ, Subbarao KV, Walsh JN (2002) Metacarbonatite or marble?-the case of the carbonate, pyroxenite, calcite-apatite rock complex at Borra, Eastern Ghats, India. J Asi Earth Sci 20:127–140

    Article  Google Scholar 

  • Leake BW, Wooley AR, Arps CE, Birch WD, Gilbert MC, Grice JD, Hawthorne FC, Kato A, Kisch HJ, Krivovichev VG, Linthout K, Laird J, Mandarino J, Maresch WV, Nickel EH, Rock NM, Schumacher JC, Smith DC, Stephenson NC, Ungaretti L, Whittaker EJ, Youzhi G (1997) Nomenclature of amphiboles. Report of the subcommittee on amphiboles of the International Mineralogical Association Commission on New Minerals and Mineral Names. Eur J Mineral 9:623–651

    Google Scholar 

  • Lentz DR (1994) Exchange reactions in hydrothermally altered rocks: examples from biotite-bearing assemblages. In: Lentz DR (ed) Alteration and alteration processes associated with ore-forming systems. Geol Assoc Can

  • Levinson AA, Bland CJ, Lively RS (1982) Exploration for U ore deposits. In: Ivanovich M, Harmon RS (ed) Uranium series disequilibrium; applications to environmental problems

  • Li YH (1991) Distribution patterns of the elements in the ocean- a synthesis. Geochim Cosmochim Acta 55:3224–3240

    Google Scholar 

  • Lindsley DH (1983) Pyroxene thermometry. Amer Mineral 68:477–493

    Google Scholar 

  • Liu G, Ai Y, Feng K, Zhang Z (1999) Metamorphic rock-hosted disseminated gold deposits: a case study of the Xiaotongjiapuzi gold deposit of Eastern Liaoning. Acta Geol Sinica 73(4):429–437

    Article  Google Scholar 

  • Moecher DP, Anderson ED, Cook CA, Mezger K (1997) The petrogenesis of metamorphosed carbonatites in the Grenville province, Ontario. Can J Earth Sci 34:1185–1201

    Article  Google Scholar 

  • Moens L, Roos P, De Rudder J, De Paepe P, Van Hende J, Waelkens M (1988) A multi-method approach to the identification of white marbles used in antique artefacts. In: Herz N, Waelkens M (eds) Classical marble: geochemistry, technology, trade, NATO ASI series, series E: applied sciences. Kluwer Academic Publishers, Dordrecht

    Google Scholar 

  • Morimoto N, Fabries J, Ferguson AK, Ginzburg IV, Ross M, Seifert FA, Zussman J (1988) Nomenclature of pyroxenes. Mineral Mag 52:535–550

    Article  Google Scholar 

  • Nimis P, Taylor WR (2000) Single clinopyroxene thermobarometry for garnet peridotites. Part I. Calibration and testing of a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer. Contrib Mineral Petrol 139:541–554

    Article  Google Scholar 

  • Osmond JK, Dabous AA, Dawood YH (1999) U series age and origin of two secondary uranium deposits, Central Eastern Desert, Egypt. Econ Geol 94:273–280

    Article  Google Scholar 

  • Rasmay AH, Takla MA, Gad MA (1983) Alteration associated with ore formation at Umm Samiuki, south Eastern Desert, Egypt. Ann Geol Surv Egypt 13:1–21

    Google Scholar 

  • Reeves RD, Brooks R (1978) Trace elements analysis of geological materials. John and Sons, Inc, New York

    Google Scholar 

  • Rosen O, Desmons J, Fettes D (2004) A systematic nomenclature for metamorphic rocks: 7. Metacarbonate and related rocks. Recommendations by the IUGS Subcommission on the systematics of metamorphic rocks. Available via SCMR http://www.bgs.ac.uk/SCMR. Accessed 31 May 2004

  • Ryabchikov ID, Barranova NN, Zotov AV, Orlova GP (1985) The stability of Au(OH) 0 in supercritical water and the metal contents of fluids in equilibrium with a granitic magma. Geochem Int 22:116–117

    Google Scholar 

  • Seward TM (1993) The hydrothermal geochemistry of gold. In: Foster RP (ed) Gold metallogeny and exploration. Chapman & Hall, pp 37–62

  • Shalaby MH, Moharem AF (2001) Geochemistry and radioelement distribution in the fresh and altered Hammamat sedimentary rocks along Wadi Belih, southern Gabal Um Tawat, north Eastern Desert, Egypt. Egypt Sediment 9:123–134

    Google Scholar 

  • Shapiro L, Brannock WW (1962) Rapid analysis of silicate, carbonate and phosphate rocks. US Geol Surv Bull 1144A, pp 56

  • Stern RJ (2002) Crustal evolution in the East African Orogen: a neodymium isotopic perspective. J Afr Earth Sci 34:109–117

    Article  Google Scholar 

  • Takla MA, El Dougdoug AA, Gad MA, Rasmay AH, El Tabbal HK (1995) Gold-bearing quartz veins in mafic and ultramafic rocks, Hutite and Um Tenedba, south Eastern Desert, Egypt. Ann Geol Surv Egypt 20:411–432

    Google Scholar 

  • Vail JR (1985) Pan-African (late Precambrian) tectonic terrains and the reconstruction of the Arabian-Nubian Shield. Geology 13:839–842

    Article  Google Scholar 

  • Viljoen MJ (1984) Archaean gold mineralization and komatiites in Southern Africa. In: Foster RP (ed) Gold 82, the geology, geochemistry and genesis of gold deposits. Balkema, Rotterdam

    Google Scholar 

  • Weber FR, McCammon RB, Rinehart CD, Light TD, Wheeler KL (2004) Geology and mineral resources of the White Mountains National Recreation Area, east-central Alaska: U.S. Geol Surv Open-File Report 88-284, 120 p

  • Williams PA (2003) Oxide zone geochemistry. New York, London, Tokyo

  • Winter JW (2001) An introduction to igneous and metamorphic petrology. Prentice-Hall Inc, Englewood Cloffs, NJ

    Google Scholar 

  • Zoheir B (2008) Characteristics and genesis of shear zone-related gold mineralization in Egypt: a case study from the Um El Tuyor mine, south Eastern Desert. Ore Geology Rev. doi:10.1016/j.oregeorev.2008.05.003

Download references

Acknowledgments

We acknowledge Profs. I. El-Aassy and M. A. Ibrahim, NMA of Egypt, for help with whole-rock chemical analyses and Mr. T. Abu Alam, Karl Franzens University of Graz, for help with EMP analyses. We express our gratitude to Profs. Hassan Harraz and Ahmed El-Kammar and two anonymous reviewers for their critical reviews and for suggestions on improvement of the manuscript. Chief Editor Prof. A. Al-Amri is thanked for handling the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to M. M. Hamdy.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Hamdy, M.M., Aly, G.A. Preliminary results of a first record of gold and uranium in marble from Central Eastern Desert, Egypt: a witness for (syn- and post-?) metamorphic mineralization in metasediments. Arab J Geosci 4, 25–43 (2011). https://doi.org/10.1007/s12517-009-0054-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12517-009-0054-0

Keywords

  • Mineralization records
  • Auriferous-uraniferous marble
  • Serpentinite
  • Metamorphism
  • Central Eastern Desert
  • Egypt