Structural control of basement denudation during rifting revealed by low-temperature (U-Th-Sm)/He thermochronology of the Socotra Island basement-Southern Gulf of Aden margin

Tectonophysics

Volumn 607, Issue , 2013, Pages 17-31

  Pik, Raphaël ^a   Bellahsen, Nicolas ^b,c   Leroy, Sylvie ^b,c   Denèle, Yoann ^b,d   Razin, Philippe ^e   Ahmed, Abdulhakim ^b,f   Khanbari, Khaled ^g  

^a UNIVERSITÉ DE LORRAINE   (France)

^b Sorbonne Universités   (France)

^c CNRS   (France)

^d UNIVERSITÉ DE TOULOUSE   (France)

^e UNIVERSITÉ BORDEAUX MONTAIGNE   (France)

^f Seismological and Volcanological Observatory Center   (Yemen)

^g Ministry of Telecommunication and Information Technology   (Yemen)

Author keywords

(U Th Sm) He thermochronology; Denudation; Passive margin; Rifting; Segmentation; Transfer fault zones

Indexed keywords

BUILDINGS; FAULT SLIPS; IMAGE SEGMENTATION; STRUCTURAL DYNAMICS; TEMPERATURE;

DENUDATION; PASSIVE MARGIN; RIFTING; THERMOCHRONOLOGY; TRANSFER FAULTS;

EROSION;

AMPLITUDE; BASEMENT ROCK; DENUDATION; FAULT ZONE; NORMAL FAULT; PASSIVE MARGIN; RIFTING; STRUCTURAL CONTROL; TECTONIC EVOLUTION; TECTONIC SETTING; THERMOCHRONOLOGY;

ARABIAN SEA; GULF OF ADEN; INDIAN OCEAN;

EID: 84886306613     PISSN: 00401951     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tecto.2013.07.038     Document Type: Article

References (98)

1. Autin J., Bellahsen N., Husson L., Beslier M.O., Leroy S., d'Acremont E. Analog models of oblique rifting in a cold lithosphere. Tectonics 2010, 29.
2. Autin J., Leroy S., Beslier M.O., d'Acremont E., Razin P., Ribodetti A., Bellahsen N., Robin C., Al Toubi K. Continental break-up history of a deep magma-poor margin based on seismic reflection data (northeastern Gulf of Aden margin, offshore Oman). Geophys. J. Int. 2010, 180(2):501-519.
3. Autin J., Bellahsen N., Leroy S., Husson L., Bellier M.-O., d'Acremont E. The role of structural inheritance in oblique rifting: insights from analogue models and application to the Gulf of Aden. Tectonophysics 2013, 607:51-64. (this volume).
4. Avigad D., Gvirtzman Z. Late Neoproterozoic rise and fall of the northern Arabian-Nubian shield: the role of lithospheric mantle delamination and subsequent thermal subsidence. Tectonophysics 2009, 477:217-228.
5. Beaumont C., Keen C.E., Boutilier R. On the evolution of rifted continental margins: comparison of models and observations for the Nova Scotian margin. Geophys. J. Roy. Astron. Soc. 1982, 70(3):667-715.
6. Bellahsen N., Daniel J.M. Fault reactivation control on normal fault growth: an experimental study. J. Struct. Geol. 2005, 27(4):769-780.
7. Bellahsen N., Fournier M., d'Acremont E., Leroy S., Daniel J.-M. Fault reactivation and rift localization: the northeastern Gulf of Aden margin. Tectonics 2006, 25.
8. Bellahsen N., Leroy S., Autin J., Razin P., d'Acremont E., Sloan H., Pik R., Ahmed A., Khanbari K. Pre-existing oblique transfer zones and transfer/transform relationships in continental margins: new insights from the southeastern Gulf of Aden, Socotra Island, Yemen. Tectonophysics 2013, 607:32-50. (this volume-a).
9. Bellahsen N., Husson L., Autin J., Leroy S., d'Acremont E. The effect of thermal weakening and buoyancy forces on rift localization: field evidences from the Gulf of Aden oblique rifting. Tectonophysics 2013, 607:80-97. (this volume-b).
10. Beydoun Z.R. Arabian Plate oil and gas; why so rich and so prolific?. Episodes 1998, 21(2):74-81.
11. Bosworth W., Huchon P., McClay K. The Red Sea and Gulf of Aden Basins. J. Afr. Earth Sci. 2005, 43:334-378.
12. Braun J. Estimating exhumation rate and relief evolution by spectral analysis of age-elevation datasets. Terra Nova 2002, 14(3):210-214.
13. Braun J. Quantifying the effect of recent relief changes on age-elevation relationships. Earth Planet. Sci. Lett. 2002, 200:331-343.
14. Braun J., Beaumont C. A physical explanation of the relation between flank uplifts and the breakup unconformity at rifted continental margins. Geology 1989, 17(8):760-764.
15. Braun J., van der Beek P. Evolution of passive margin escarpments: what can we learn from low-temperature thermochronology?. J. Geophys. Res. Earth Surf. 2004, 109(F4).
16. Braun J., vanderBeek P., Batt G.E. Quantitative Thermochronology. Numerical Methods for the Interpretation of Thermochronological Data 2006, Cambridge University Press, Cambridge.
17. Braun J., van der Beek P., Valla P., Robert X., Herman F., Glotzbach C., Pedersen V., Perry C., Simon-Labric T., Prigent C. Quantifying rates of landscape evolution and tectonic processes by thermochronology and numerical modeling of crustal heat transport using PECUBE. Tectonophysics 2012, 524:1-28.
18. Brown R.W., Summerfield M.A., Gleadow A.J.W. Denudational history along a transect across the Drakensberg Escarpment of southern Africa derived from apatite fission track thermochronology. J. Geophys. Res. 2002, 107(B12).
19. Carignan J., Hild P., Mevelle G., Morel J., Yeghicheyan D. Routine analyses of trace element in geological samples using flow injection and low pressure on-line liquid chromatography coupled to ICP-MS: a study of geochemical reference materials BR, DR-N, UB-N, AN-G and GH. Geostand. Newslett. 2001, 25:187-198.
20. Cochran J.R. The Gulf of Aden: structure and evolution of a young i-ocean basion and continental margin. J. Geophys. Res. 1981, 86:263-288.
21. Cogné N., Gallagher K., Cobbold P.R. Post-rift reactivation of the onshore margin of southeast Brazil: evidence from apatite (U-Th)/He and fission-track data. Earth Planet. Sci. Lett. 2011, 309:118-130.
22. Cokburn H.A.P., Brown R.W., Summerfied M.A., Seidl M.A. Quantifying passive margin denudation and landscape development using a combined fission-track thermochronology and cosmogenic isotope analysis approach. Earth Planet. Sci. Lett. 2000, 179(3-4):429-435.
23. d'Acremont E., Leroy S., Beslier M.O., Bellahsen N., Fournier M., Robin C., Maia M., Gente P. Structure and evolution of the eastern Gulf of Aden conjugate margins from seismic reflection data. Geophys. J. Int. 2005, 160(3):869-890.
24. d'Acremont E., Leroy S., Maia M., Patriat P., Beslier M.O., Bellahsen N., Fournier M., Gente P. Structure and evolution of the eastern Gulf of Aden: insights from magnetic and gravity data (Encens-Sheba MD117 cruise). Geophys. J. Int. 2006, 165(3):786-803.
25. d'Acremont E., Leroy S., Maia M., Gente P., Autin J. Volcanism, jump and propagation on the Sheba ridge, eastern Gulf of Aden: segmentation evolution and implications for oceanic accretion processes. Geophys. J. Int. 2010, 180(2):535-551.
26. Davis M., Kusznir N. Depth-dependent lithospheric stretching at rifted continental margins. Proc. NSF Rifted Margins Theoretical Institute 2004, 1:92-136.
27. Denele Y., Leroy S., Pelleter E., Pik R., Talbot J.Y., Khanbari K. The Cryogenian arc formation and successive high-K calc-alkaline plutons of Socotra Island (Yemen). Arab. J. Geosci. 2012, 5(5):903-924.
28. Ehlers T.A. Crustal thermal processes and the interpretation of thermochronometer data. Rev. Mineral. Geochem. 2005, 58(1):315-350.
29. Ehlers T.A., Armstrong P.A., Chapman D.S. Normal fault thermal regimes and the interpretation of low-temperature thermochronometers. Phys. Earth Planet. Inter. 2001, 126:179-194.
30. Fantozzi P.L., Sgavetti M. Tectonic and sedimentary evolution of the eastern Gulf of Aden continental margins: new structural and stratigraphic data from Somalia and Yemen. Sedimentation and Tectonics of Rift Basins: Red Sea-Gulf of Aden 1988, 55-76. CRC Press, Boca Raton, FL. B. Bosence (Ed.).
31. Farley K.A. (U-Th)/He dating; techniques, calibrations, and applications. Rev. Mineral. Geochem. 2002, 47(819-844).
32. Flowers R.M. Exploiting radiation damage control on apatite (U-Th)/He dates in cratonic regions. Earth Planet. Sci. Lett. 2009, 277(1-2):148-155.
33. Flowers R.M., Shuster D.L., Wernicke B.P., Farley K.A. Radiation damage control on apatite (U-Th)/He dates from the Grand Canyon region, Colorado Plateau. Geology 2007, 35:447-450.
34. Flowers R.M., Wernicke B.P., Farley K.A. Unroofing, incision and uplift history of the southwestern Colorado Plateau from apatite (U-Th)/He thermochronometry. Geol. Soc. Am. Bull. 2008, 120:571-587.
35. Flowers R.M., Ketcham R.A., Shuster D.L., Farley K.A. Apatite (U-Th)/He thermochronometry using a radiation damage accumulation and annealing model. Geochim. Cosmochim. Acta 2009, 73(8):2347-2365.
36. Foster D.A., Gleadow A.J.W. Structural framework and denudation history of the flanks of the Kenya and Anza rifts, East Africa. Tectonics 1996, 15:258-271.
37. Fournier M., Bellahsen N., Fabbri O., Gunnell Y. Oblique rifting and segmentation of the NE Gulf of Aden passive margin. Geochem. Geophys. Geosyst. 2004, 5.
38. Fournier M., Chamot-Rooke N., Petit C., Huchon P., Al-Kathiri A., Audin L., Beslier M.O., d'Acremont E., Fabbri O., Fleury J.M., Khanbari K., Lepvrier C., Leroy S., Maillot B., Merkouriev S. Arabia-Somalia plate kinematics, evolution of the Aden-Owen-Carlsberg triple junction, and opening of the Gulf of Aden. J. Geophys. Res. Solid Earth 2010, 115.
39. Gallagher K.C., Hawkesworth J.M., Montavoni S.M. The denudation history of the onshore continental margin of SE Brazil inferred from apatite fission track data. J. Geophys. Res. 1994, 99(B9):18117-18145.
40. Gautheron C.E., Tassan-Got L., Farley K.A. (U-Th)/Ne chronometry. Earth Planet. Sci. Lett. 2006, 243(3-4):520-535.
41. Green P.F., Duddy I.R. Interpretation of apatite (U-Th)/He ages and fission track ages from cratons. Earth Planet. Sci. Lett. 2006, 244(3-4):541-547.
42. Green P.F., Crowhurst P.V., Duddy I.R., Japsen P., Holford S.P. Conflicting (U-Th)/He and fission track ages in apatite: enhanced He retention, not anomalous annealing behaviour. Earth Planet. Sci. Lett. 2006, 250(3-4):407-427.
43. Gunnell Y., Carter A., Petit C., Fournier M. Post-rift seaward downwarping at passive margins: new insights from southern Oman using stratigraphy to constrain apatite fission-track and (U-Th)/He dating. Geology 2007, 35(7):647-650.
44. Hofmann C., Courtillot V., Féraud G., Rochette P., Yirgu G., Ketefo E., Pik R. Timing of the Ethiopian flood basalt event and implications for plume birth and global change. Nature 1997, 389:838-841.
45. Huchon P., Khanbari K. Rotation of the syn-rift stress field of the northern Gulf of Aden margin, Yemen. Tectonophysics 2003, 364(3-4):47-166.
46. Huismans R., Beaumont C. Depth-dependent extension, two-stage breakup and cratonic underplating at rifted margins. Nature 2011, 473:74-79.
47. Ketcham R. Forward and inverse modeling of low temperature thermochronometry data. Thermochronology 2005, 275-314. P.W. Reiners, T.A. Ehlers (Eds.).
48. King G.P., Stein R.S., Rundle J.B. The growth of geological structures by repeated earthquakes (1, Conceptual framework). J. Geophys. Res. 1988, 93:13,307-13,318.
49. Kraml M., Pik R., Rahn M., Carignan J., Keller J. A new multi-mineral age reference material for 40Ar/39Ar, (U-Th)/He and fission track dating methods: the Limberg t3 tuff. Geostand. Geoanal. Res. 2006, 30:73-86.
50. Lavier L.L., Manatschal G. A mechanism to thin the continental lithosphere at magma-poor margins. Nature 2006, 440(7082):324-328.
51. Lemoine M., Bas T., Arnaud-Vanneau A., Arnaud H., Dumont T., Gidon M., Bourbon M., Graciansky P.C.d, Rudkiewicsz J.L., Megard-Galli J., Tricart P. The continental margin of the Mesozoic Tethys in the Western Alps. Mar. Pet. Geol. 1986, 3(3):179-199.
52. Lepvrier C., Fournier M., Bérard T., Roger J. Cenozoic extension in coastal Dhofar (southern Oman): implications on the oblique rifting of the Gulf of Aden. Tectonophysics 2002, 357:279-293.
53. Leroy S., d'Acremont E., Tiberi C., Basuyau C., Autin J., Lucazeau F., Sloan H. Recent off-axis volcanism in the eastern Gulf of Aden: implications for plume-ridge interaction. Earth Planet. Sci. Lett. 2010, 293(1-2):140-153.
54. Leroy S., Lucazeau F., d'Acremont E., Watremez L., Autin J., Rouzo S., Bellahsen N., Tiberi C., Ebinger C., Beslier M.O., Perrot J., Razin P., Rolandone F., Sloan H., Stuart G., Al Lazki A., Al-Toubi K., Bache F., Bonneville A., Goutorbe B., Huchon P., Unternehr P., Khanbari K. Contrasted styles of rifting in the eastern Gulf of Aden: a combined wide-angle, multichannel seismic, and heat flow survey. Geochem. Geophys. Geosyst. 2010, 11.
55. Leroy S., Razin P., Autin J., Bache F., d'Acremont E., Watremez L., Robinet J., Baurion C., Denele Y., Bellahsen N., Lucazeau F., Rolandone F., Rouzo S., Kiel J.S., Robin C., Guillocheau F., Tiberi C., Basuyau C., Beslier M.O., Ebinger C., Stuart G., Ahmed A., Khanbari K., Al Ganad I., de Clarens P., Unternehr P., Al Toubi K., Al Lazki A. From rifting to oceanic spreading in the Gulf of Aden: a synthesis. Arab. J. Geosci. 2012, 5(5):859-901.
56. Lucazeau F., Leroy S., Bonneville A., Goutorbe B., Rolandone F., D'Acremont E., Watremez L., Dusunur D., Tuchais P., Huchon P., Bellahsen N., Al-Toubi K. Persistent thermal activity at the Eastern Gulf of Aden after continental break-up. Nat. Geosci. 2008, 1(12):854-858.
57. Lucazeau F., Leroy S., Autin J., Bonneville A., Goutorbe B., Watremez L., d'Acremont E., Dusunur D., Rolandone F., Huchon P., Bellahsen N., Tuchais P. Post-rift volcanism and high heat-flow at the ocean-continent transition of the eastern Gulf of Aden. Terra Nova 2009, 21(4):285-292.
58. Macdonald K., Scheirer D., 1, S.C. Mid-ocean ridges: discontinuities, segments and giant cracks. Science 1991, 253:986-994.
59. Manatschal G. New models for evolution of magma-poor rifted margins based on a review of data and concepts from West Iberia and the Alps. Int. J. Earth Sci. 2004, 93(3):432-466.
60. McKenzie D.P. Some remarks on the development of sedimentary basins. Earth Planet. Sci. Lett. 1978, 40(20-32).
61. Menzies M., Gallagher K., Yelland A., Hurford A.J. Volcanic and nonvolcanic rifted margins of the Red Sea and Gulf of Aden; crustal cooling and margin evolution in Yemen. Geochim. Cosmochim. Acta 1997, 61(12):2511-2527.
62. Mohn G., Manatschal G., Muntener O., Beltrando M., Masini E. Unravelling the interaction between tectonic and sedimentary processes during lithospheric thinning in the Alpine Tethys margins. Int. J. Earth Sci. 2010, 99:S75-S101.
63. Morley C.K. Extension, detachments and sedimentation in continental rifts (with particular reference to East Africa). Tectonics 1989, 8:1175-1192.
64. Moulin M., Aslanian D., Olivet J.L., Contrucci I., Matias L., Geli L., Klingelhoefer F., Nouze H., Rehault J.P., Unternehr P. Geological constraints on the evolution of the Angolan margin based on reflection and refraction seismic data (ZaiAngo project). Geophys. J. Int. 2005, 162:793-810.
65. Omar G.I., Steckler M.S. Fission track evidence on the initial rifting of the Red Sea: two pulses, no propagation. Science 1995, 270:1341-1344.
66. Peron-Pinvidic G., Manatschal G., Dean S., Minshull T.A. Compressional structures on the West Iberia rifted margin: what controls their distribution?. The Nature and Origin of Compression in Passive Margins 2008, 169-183. Geological Society of London. H.E.A. Jonhson (Ed.).
67. Peron-Pinvidic G., Manatschal G., Osmundsen P.T. Structural comparison of archetypal Atlantic rifted margins: a review of observations and concepts. Mar. Pet. Geol. 2013, 43:21-47.
68. Persano C., Stuart F.M., Bishop P., Barfod D.N. Apatite (U-Th)/He age constraints on the development of the Great Escarpment on the southeastern Australian passive margin. Earth Planet. Sci. Lett. 2002, 200(1-2):79-90.
69. Persano C., Bishop P., Stuart F.M. Apatite (U-Th)/He age constraints on the Mesozoic and Cenozoic evolution of the Bathurst region, New South Wales: evidence for antiquity of the continental drainage divide along a passive margin. Aust. J. Earth Sci. 2006, 53(6):1041-1050.
70. Petit C., Fournier M., Gunnell Y. Tectonic and climatic controls on rift escarpments: erosion and flexural rebound of the Dhofar passive margin (Gulf of Aden, Oman). J. Geophys. Res. Solid Earth 2007, 112(B3).
71. Pik R., Marty B., Carignan J., Lavé J. Stability of the Upper Nile drainage network (Ethiopia) deduced from (U-Th)/He thermochronometry: implications for uplift and erosion of the Afar plume dome. Earth Planet. Sci. Lett. 2003, 215:73-88.
72. Pik R., Marty B., Hilton D.R. How many mantle plumes in Africa? The geochemical point of view. Chem. Geol. 2006, 226:100-114.
73. Pik R., Marty B., Carignan J., Yirgu G., Ayalew T. Timing of East African Rift development and topographical evolution in Southern Ethiopia. Geology 2008, 36:167-170.
74. Razin P., Robinet J., Kiel J.S., Bellahsen N. The RST, Bordeaux, Octobre 2010, C.G.D.T.-S.s.-r.e.p.-r.o.-m.s.l.m.s.d.g.d.A.I.d.S.Y.P.p.a Dispositifs Tecto-Sédimentaires syn-rift et post-rift oligo-miocènes sur la marge sud du golfe d'Aden-Ile de Socotra (Yémen), Paper presented at the RST, Bordeaux, Octobre 2010.
75. Reiners P.W., Farley K.A. Influence of crystal size on apatite (U-Th)/He thermochronology; an example from the Bighorn Mountains, Wyoming. Earth Planet. Sci. Lett. 2001, 188(3-4):413-420.
76. Robinet J. Evolution tectono-sédimentaire des marges orientale et méridionale de la plaque Arabe (Sultanat d'Oman) 2013, (Thèse de doctorat), Université Pierre et Marie Curie, Paris, (VI, 322pp.).
77. Robinet J., Razin P., Serra-Kiel S., Garcia A.G., Leroy S., Roger J., Grelaud C. The Paleogene pre-rift to syn-rift succession in the Dhofar margin (northeastern Gulf of Aden): Stratigraphy and depositional environments. Tectonophysics 2013, 607:1-16. (this volume).
78. Roger J., Platel J.P., Cavelier C., Bourdillon-de-Grisac C. D.n.s.l.s.e.l.h.g.d.D.S.d.O. Bull. Soc. Géol. Fr. 1989, 2:265-277.
79. Données nouvelles sur la stratigraphie et l'histoire géologique du Dhofar (Sultanat d'Oman). Bull. Soc. Géol. Fr. 1989, 2:265-277. (2: 265-277).
80. Rosendahl B.R. Architecture or continental rifts with special reference to East Africa. Ann. Rev. Earth Planet. Sci. 1987, 15:445-503.
81. Royden L., Keen C.E. Rifting process and thermal evolution of the continental margin of eastern Canada determined from subsidence curves. Earth Planet. Sci. Lett. 1980, 51:343-361.
82. Royer J.Y. Paleogene plate tectonic evolution of the Arabian and eastern Somali Basins. Geol. Soc. Spec. Publ. 2002, 195:7-23.
83. Scotese C.R., Gahagan L.M., Larson R.L. Plate tectonic reconstructions of the Cretaceous and Cenozoic ocean basins. Tectonophysics 1988, 155(1-4):27-48.
84. Shuster D.L., Farley K.A. The influence of artificial radiation damage and thermal annealing on helium diffusion kinetics in apatite. Geochim. Cosmochim. Acta 2009, 73(1):183-196.
85. Shuster D.L., Flowers R.M., Farley K.A. The influence of natural radiation damage on helium diffusion kinetics in apatite. Earth Planet. Sci. Lett. 2006, 249(3-4):148-161.
86. Spiegel C., Kohn B.P., Belton D.X., Gleadow A.J.W. Morphotectonic evolution of the central Kenya rift flanks: implications for late Cenozoic environmental change in East Africa. Geology 2007, 35:427-430.
87. Spotila J.A., Bank G.C., Reiners P.W., Naeser C.W., Naeser N.D., Henika B.S. Origin of the Blue Ridge escarpment along the passive margin of Eastern North America. Basin Res. 2004, 16(1):41-63.
88. Stockli D.F., Surpless B.E., Dumitru T.A. Thermochronological constraints on the timing and magnitude of Miocene and Pliocene extension in the central Wassuk Range, western Nevada. Tectonics 2002, 21(4):1028.
89. Taylor B., Goodliffe A., Martinez F. Initiation of transform faults at rifted continental margins. C. R. Geosci. 2009, 341:428-438.
90. Valla P.G., van der Beek P.A., Braun J. Rethinking low-temperature thermochronology data sampling strategies for quantification of denudation and relief histories: a case study in the French western Alps. Earth Planet. Sci. Lett. 2011, 307(3-4):309-322.
91. Van der Beek P., Mbede E., Andriessen P., Delvaux D. Denudation history of the Malawi and Rukwa Rift flanks (East African Rift System) from apatite fission track thermochronology. J. Afr. Earth Sci. 1998, 26(3):363-385.
92. van der Beek P., Summerfield M.A., Braun J., Brown R.W., Fleming A. Modeling postbreakup landscape development and denudational history across the southeast African (Drakensberg Escarpment) margin. J. Geophys. Res. Solid Earth 2002, 107(B12).
93. Watchorn F., Nichols G.J., Bosence D.W.J. Rift-related sedimentation and stratigraphy, southern Yemen (Gulf of Aden). Sedimentation and Tectonics in the Rift Basins Red Sea-Gulf of Aden 1998, 165-189. Chapman & Hall, London. B. Bosence (Ed.).
94. Watremez L., Leroy S., Rouzo S., d'Acremont E., Unternehr P., Ebinger C., Lucazeau F., Al-Lazki A. The crustal structure of the north-eastern Gulf of Aden continental margin: insights from wide-angle seismic data. Geophys. J. Int. 2011, 184(2):575-594.
95. Weissel J.K., Karner G.D. Flexural uplift of rift flanks due to mechanical unloading of the lithosphere during extension. J. Geophys. Res. Solid Earth Planets 1989, 94(B10):13919-13950.
96. Whitmarsh R.B., Manatschal G., Minshull T.A. Evolution of magma-poor continental margins from rifting to seafloor spreading. Nature 2001, 413:150-154.
97. Wolf R.A., Farley K.A., Kass D.M. Modeling of the temperature sensitivity of the apatite (U-Th)/He thermochronometer. Chem. Geol. 1998, 148:105-114.
98. Ziegler M.A. Late Permian to Holocene paleofacies evolution of the Arabian Plate and its hydrocarbon occurrences. GeoArabia 2001, 6(3):445-504.