Abstract
The Rwenzori Mountains (Mtns) in west Uganda are the highest rift mountains on Earth and rise to more than 5,000 m. We apply low-temperature thermochronology (apatite fission-track (AFT) and apatite (U–Th–Sm)/He (AHe) analysis) for tracking the cooling history of the Rwenzori Mtns. Samples from the central and northern Rwenzoris reveal AFT ages between 195.0 (±8.4) Ma and 85.3 (±5.3) Ma, and AHe ages between 210.0 (±6.0) Ma to 24.9 (±0.5) Ma. Modelled time–temperature paths reflect a protracted cooling history with accelerated cooling in Permo-Triassic and Jurassic times, followed by a long period of constant and slow cooling, than succeeded by a renewed accelerated cooling in the Neogene. During the last 10 Ma, differentiated erosion and surface uplift affected the Rwenzori Mtns, with more pronounced uplift along the western flank. The final rock uplift of the Rwenzori Mtns that partly led to the formation of the recent topography must have been fast and in the near past (Pliocene to Pleistocene). Erosion could not compensate for the latest rock uplift, resulting in Oligocene to Miocene AHe ages.
Similar content being viewed by others
References
Abbate E, Balestrieri ML, Bigazzi G (2002) Morphostructural development of the Eritrean rift flank (southern Red Sea) inferred from apatite fission track analysis. J Geophys Res 107:2319–2331
Abeinomugisha D, Mugisha F (2004) Structural analysis of the Albertine graben, Western Uganda. Abstract, East African rift System Evolution, Resources and Environmental Conference, Addis Abeba, June 2004
Ahnert F (2003) Einführung in die Geomorphologie. Ulmer, Stuttgart
Bahat D, Mohr P (1987) Horst faulting in continental rifts. Tectonophysics 141:61–73
Batt GE, Brandon MT (2002) Lateral thinking: 2-D interpretation of thermochronology in convergent orogenic settings. Tectonophysics 349(1–4):185–201
Bauer FU, Karl M, Glasmacher UA, Nagudi B, Andreas S, Mroszewski L (in review) The Rwenzori Mountains of western Uganda–an approach to unravel the evolution of a remarkable morphological feature within the Albertine Rift. Submitted to J Afr Earth Sci
Bishop P (2007) Long-term landscape evolution: linking tectonics and surface processes. Earth Surf Proc Land 32:329–365
Boven A, Pasteels P, Punzalan LE, Yamba TK, Musisi JH (1998) Quaternary perpotassic magmatism in Uganda (Tore-Ankole Volcanic Province): age assessment and significance for magmatic evolution along the East African Rift. J Afr Earth Sci 26(3):463–476
Braun J (2002) Quantifying the effect of recent relief changes on age-elevation relationships. Earth Planet Sci Lett 200:331–343
Bumby AJ, Guiraud R (2005) The geodynamic setting of the Phanerozoic basins of Africa. J Afr Earth Sci 43(1–3):1–12
Davis W (1899) The geographical cycle. Geogr J 14:481–504
Delvaux D, Barth A (2010) African Stress Pattern from formal inversion of focal mechanism data. Implications for rifting dynamics. Tectonophysics 482:105–128
Dodson MH (1973) Closure temperature in cooling geochronological and petrological systems. Contrib Mineral Petrol 40:259–274
Donelick RA, Ketcham RA, Carlson WD (1999) Variability of apatite fission-track annealing kinetics II: crystallographic orientation effects. Am Mineral 84:1224–1234
D’Oreye N, Cayol V, Kervyn F, GVO (2007) The November 2006 Nyamulagira eruption revealed by lnSAR. Proceeding of the 26th ECGS workshop, AVCOR07, Luxemburg, November 2007
Donelick RA, O’Sullivan PB, Ketcham RA (2005) Apatite fission-track analysis. Rev Mineral Geochem 58:49–94
Dunkl I (2002) Trackkey: a Windows program for calculation and graphical presentation offission track data. Comput Geosci 28:3–12
Ebinger CJ (1989) Tectonic development of the western branch of the East African rift system. Geol Soc Am Bull 101:885–903
Ebinger CJ, Furman T (2002) Geodynamical setting of the Virunga Volcanic Province, East Africa. Acta Vulcanol 14(1–2):1–8
Ebinger CJ, Sleep NH (1998) Cenozoic magmatism throughout East Africa resulting from impact of a single plume. Nature 395:788–791
Ebinger CJ, Deino AL, Tesha AL, Becker T, Ring U (1993) Tectonic controls on rift basin morphology: evolution of the Northern Malawi (Nyasa) Rift. J Geophys Res 98(B10):17,821–17,836
Emmel B, Jöns N, Kroener A, Jacobs J, Wartho J-A, Schenk V, Razakamanana T, Austegard A (2008) From closure of the mozambique ocean to gondwana breakup: new evidence from geochronological data of the vohibory terrane, Southwest Madagascar. J Geol 116(1):21–38
England P, Molnar P (1990) Surface uplift, uplift of rocks, and exhumation of rocks. Geology 18:1173–1177
Farley KA (2000) Helium diffusion from apatite: general behaviour as illustrated by Durango fluorapatite. J Geophys Res 105(B2): 2903–2914
Farley KA, Wolf RA, Silver LT (1996) The effects of long-alpha-stopping distances on (U–Th)/He ages. Geochim Cosmochim Acta 60:4223–4229
Fitzgerald PG, Baldwin SL, Webb LE, O’Sullivan PB (2006) Interpretation of (U-Th)/He single grain ages from slowly cooled crustal terranes: a case study from the Transantarctic Mountains of southern Victoria Land. Chem Geol 225(1–2):91–120
Flowers RM, Bowring SA, Reiners PW (2006) Low long-term erosion rates and extreme continental stability documented by ancient (U–Th)/He dates. Geology 34:925–928
Flowers RM, Ketcham RA, Shuster DL, Farley KA (2009) Apatite (U–Th)/He thermochronometry using a radiation damage accumulation and annealing model. Geochim Cosmochim Acta 73(8):2347–2365. doi:10.1016/j.gca.2009.01.015
Foster DA, Gleadow AJW (1992) The morphotectonic evolution of rift-margin mountains in central Kenya: constraints from apatite fission-track thermochronology. Earth Planet Sci Lett 113:157–171
Foster DA, Gleadow AJW (1993) Episodic denudation in East Africa: a legacy of intracontinental tectonism. Geophys Res Lett 20(21):2395–2398
Foster DA, Gleadow AJW (1996) Structural framework and denudation history of the flanks of the Kenya and Anza Rifts, East Africa. Tectonics 15:258–271
Galbraith RF (1981) On statistical models for fission track counts. Math Geol 13(6):471–478
Green PF (1981) ‘Track-in track’ length measurements in annealed apatites. Nucl Tracks 5:121–128
Green PF (1988) The relationship between track shortening and fission track age reduction in apatite: combined influences of inherent instability, annealing anisotropy, length bias and system calibration. Earth Planet Sci Lett 89(3–4):335–352
Green PF, Durrani SA (1977) Annealing studies of tracks in crystals. Nucl Track Detect 1:33–39
Grist AM, Ravenhurst CE (1992a). Mineral separation techniques used at Dalhousie University. In: Zentilli M, Reynolds PH (eds), Short course handbook on low temperature thermochronology, 1992. Mineral Associ Can Short Course Handb 20 Append 2: 203–209
Grist AM, Ravenhurst CE (1992b). A step-by-step laboratory guide to fission track thermochronology at Dalhousie University. In: Zentilli M, Reynolds PH (eds), Short course handbook on low temperature thermochronology, 1992. Mineral Associ Can Short Course Handb 20 Append 1:190–201
Haines S (2008) Transformations in clay-rich fault rocks: constraining fault zone processes and the kinematic evolution of regions. Master Thesis, University of Michigan
Hurford AJ (1990) Standardization of fission track dating calibration: recommendation by the fission track working group of the I.U.G.S. Subcommission on geochronology. Chem Geol 80:171–178
Hurford AJ, Green PF (1982) A user’s guide to fission-track dating calibration. Earth Planet Sci Lett 59:343–354
Hurford AJ, Green PF (1983) The Zeta age calibration of fission-track dating. Isot Geosci 1:285–317
Kampunzu AB, Bonhomme MG, Kanika M (1998) Geochronology of volcanic rocks and evolution of the Cenozoic Western Branch of the East African Rift System. J Afr Earth Sci 26(3):441–461
Karner GD, Byamungu BR, Ebinger CJ, Kampunzu AB, Mukasa RK, Nyakaana J, Rubondo ENT, Upcott NM (2000) Distribution of crustal extension and regional basin architecture of the Albertine rift system, East Africa. Mar Petrol Geol 17:1131–1150
Ketcham RA (2005) Forward and inverse modelling of low-temperature thermochronometry data. In: Reiners PW, Ehlers TA (eds), Low-temperature thermochronology: techniques, interpretations and applications. Rev Mineral Geochem 58:275–314
Ketcham (2009) HeFTy version 1.6.7, Manual
Ketcham RA, Donelick RA, Carlson WD (1999) Variability of apatite fission-track annealing kinetics: III. Extrapolation to geological time scales. Ame Mineral 84:1235–1255
Ketcham RA, Carter A, Donelick RA, Barbarand J, Hurford AJ (2007a) Improved measurements of fission-track annealing in apatite. Ame Mineral 92:789–798
Ketcham RA, Carter A, Donelick RA, Barbarand J, Hurford AJ (2007b) Improved modeling of fission-track annealing in apatite. Ame Mineral 92:799–810
Ketcham RA, Donelick RA, Balestrieri ML, Zattin M (2009) Reproducibility of apatite fission-track length data and thermal history reconstruction. Earth Planet Sci Lett 284:504–515
Koehn D, Aanyu K, Haines S, Sachau T (2008) Rift nucleation, rift propagation and the creation of basement micro-plates within active rifts. Tectonophysics 458:105–116
Koehn D, Lindenfeld M, Rümpker G, Aanyu, Haines S, Passchier C (2010) Active transsection faults in rift transfer zones: Evidence for rotating stress fields in the East African Rift and implications for crustal fragmentation processes. Int J Earth Sci (this issue)
Kooi H, Beaumont C (1994) Escarpment evolution on high-elevation rifted margins: insights derived from a surface processes model that combines diffusion, advection, and reaction. J Geophys Res 99:12,191–12,209
Kooi H, Beaumont C (1996) Large-scale geomorphology: classical concepts reconciled and integrated with contemporary ideas via a surface processes model. J Geophys Res 101:3361–3386
Laerdal T, Talbot MR (2002) Basin neotectonics of Lakes Edward and George, East African Rift. Palaeogeogr Palaeoclimatol Palaeoecol 187:213–232
Laslett GM, Gleadow AJW, Duddy IR (1984) The relationship between fission track length and track density distributions. Nucl Tracks 9:29–38
Lisker F, Ventura B, Glasmacher UA (2009) Apatite thermochronology in modern geology. Geol Soc London Spec Publ 324:1–23
Logatchev NA, Beloussov VV, Milanovsky EE (1972) East African Rift Development. Tectonophysics 15:71–81
MacPhee D (2006) Exhumation, Rift-flank uplift, and Thermal Evolution of the Rwenzori Mountains Determined by Combined (U-Th)/He and U-Pb Thermochronometry. Master Thesis, Massachusetts Institute of Technology
Mbede EL (2001) Tectonic setting and uplift analysis of the Pangani Rift Basin in Northern Tanzania using apatite fission track thermochronology. Tanzan J Sci 27A (Abstr vol)
McConnell RB (1959) Outline of the geology of the Ruwenzori Mountains, a preliminary account of the results of the British Ruwenzori expedition, 1951–1952. Overseas Geol Miner Resour 7(3):245–268
Michot F (1938) Etude pétrographique et géologique du Ruwenzori septentrional. Mém Inst Roy Colon Belg Sect Sc Nat Med 8:66–271
Mitchell SG, Reiners PW (2003) Influence of wildfires on apatite and zircon (U-Th)/He ages. Geology 31:1025–1028
Montgomery DR, Brandon MT (2002) Topographic controls on erosion rates in tectonically active mountain ranges. Earth Planet Sci Lett 201:481–489
Morley CK (1999) Tectonic evolution of the East African Rift System and the modifying influence of magmatism: a review. Acta Vulcanol 11(1):1–19
Nagudi B, Bauer FU, Glasmacher UA, Foerster A, Foerster H-J, Schumann A, Kontny J (in preparation) Petrography and geochemistry of Rwenzori Mountains lithologies, East African Rift System, Uganda
Noble WP, Foster DA, Gleadow AJW (1997) The post-Pan-African thermal and extensional history of the crystalline basement rocks in eastern Tanzania. Tectonophysics 275:331–350
Nyblade AA (1997) Heat flow across the East African Plateau. Geophys Res Lett 24(16):2083–2086
Nyblade AA, Brazier RA (2002) Precambrian lithospheric controls on the development of the East African rift system. Geology 30(8):755–758
Nyblade AA, Pollack HN, Jones DL, Podmore F, Musjayandebvu M (1990) Terrestrial heat flow in East and Southern Africa. J Geophys Res 95:17,371–17,384
Ollier CD, Pain CF (2000) The origin of mountains. Routledge, London
Osmaston HA, Harrison SP (2005) The late Quaternary glaciation of Africa: a regional synthesis. Quatern Int 138:32–54
Ovington T, Burdon P (2009) Upper Pliocene Fluvio-DElataic Reservoirs of the Victoria Nile/Butiaba Play, Alpert Rift, Western Uganda. PESGB Conference September 2009, London
Petters SW (1991) Regional geology of Africa. In: Bhattacharji S, Friedmann GM, Neugebauer HJ, Seilacher A (eds) Lect Notes Earth Sci 40. Springer, Heidelberg
Pickford M (1990) Uplift of the Roof of Africa and its bearing on the Evolution of mankind. Human Evol 5(1):1–20
Pickford M, Senut B, Hadoto D (1993) Geology and paleobiology of the albertine rift valley in uganda-zaire. vol I, Geol Occas Publ 24 Centre International pour la Formation et les Echanges Geologiques, Orléans
Pik R, Marty B, Carignan J, Lavé J (2003) Stability of the Upper Nile drainage network (Ethiopia) deduced from (U-Th)/He thermochronometry: implications for uplift and erosion fo the Afar plume dome. Earth Planet Sci Lett 215:73–88
Pik R, Marty B, Carignan J, Yirgu G, Ayalew T (2008) Timing of East African Rift development in southern Ethiopia: implication for mantle plume activity and evolution of topography. Geology 36:167–170
Reiners PW, Brandon MT (2006) Using thermochronology to understand orogenic erosion. Annu Rev Earth Planet Sci 34:419–466
Reiners PW, Ehlers TA (2005) Low-temperature thermochronology: techniques, interpretations and applications. Rev Mineral Geochem 58:151–176
Reiners PW, Farley KA (2001) Influence of crystal size on apatite (U-Th)/He thermochronology: an example from the Bighorn Mountains, Wyoming. Earth Planet Sci Lett 188:413–420
Reiners PW, Nicolescu S (2006) Measurement of parent nuclides for (U-Th)/He chronometry by solution sector ICP-MS, ARHDL Report 1, University of Arizona
Reiners PW, Shuster DL (2009) Thermochronology and landscape evolution. Phys Today 62(9):31–36
Ring U (2008) Extreme uplift of the Rwenzori Mountains in the East African Rift, Uganda: Structural framework and possible role of glaciations. Tectonics 27 (TC4018). doi:10.1029/2007TC002176
Ring U, Betzler C (1995) Geology of the Malawi Rift: kinematic and tectono-sedimentary background to the Chiwondo Beds, northern Malawi. J Hum Evol 28(1):7–21
Ring U, Betzler C, Delvaux D (1992) Normal versus strike-slip faulting during rift development in East Africa: the Malawi rift. Geology 20:1015–1018
Roller S, Hornung J, Hinderer M, Ceglarek J, Ssemmanda I (2008) A Middle Miocene to Pleistocene synrift sedimentary sequence in the southern Albertine Grabend (Uganda). 26th IAS Regional Meeting/SEPM-CES SEDIMENT 2008, Bochum, Abstract Volume, SDGG 58
Schlueter T (1994) Zur Verbreitung, Fazies und Stratigraphie der Karoo in Uganda. Berliner Geowiss Abh E13:453–467
Schlueter T (1997) Geology of East Africa. Gebr. Bortntraeger, Berlin, Stuttgart
Shuster DL, Farley KA (2009) The influence of artificial radiation damage and thermal annealing on helium diffusion kinetics in apatite. Geochim Cosmochim Acta 73(1):183–196
Shuster DL, Flowers RM, Farley KA (2006) The influence of natural radiation damage on helium diffusion kinetics in apatite. Earth Planet Sci Lett 249:148–161
Sobel ER, Seward D (2010) Influence of etching conditions on apatite fission-track etch pit diameter. Chem Geol 271:59–69
Spiegel C, Kohn BP, Belton DX, Gleadow AJW (2004) Integrating apatite fission track and (U-Th)/He data: the thermal evolution of rift-valley flanks in central Kenya. Abstract book, Int. Fission-track conference 2004, Amsterdam
Spiegel C, Kohn BP, Belton DX, Gleadow AJW (2007) Morphotectonic evolution of the central Kenya rift flanks: implications for late cenozoic environmental change in East Africa. Geology 35(5):427–430
Tanner PWG (1971) The Stanley Volcanics formation of Ruwenzori, Uganda. Fifteenth Annual Report of the Research Institute of African Geology, University of Leeds
Taylor RG, Howard KWF (1998) Post-Palaeozoic evolution of weathered land surfaces in Uganda by tectonically controlled deep weathering and stripping. Geomorphology 25(3–4):173–192
Torsvik TH, Gaina C, Redfield TF (2008) Antarctica and global paleogeography: fromRodinia, through Gondwanaland and Pangea, to the birth of the Southern Ocean and the opening of gateways. In Antarctica: A Keystone in a ChangingWorld, Proceedings 10th Int Symp Antarctic Earth Sci, The National Academies Press, Washington, pp 125–140
Upcott NM, Mukasa RK, Ebinger CJ (1996), Along-axis segmentation and isostasy in the Western rift, East Africa. J Geophys Res 101(B2): 3247–3268
Van Damme D, Pickford M (2003) The late Cenozoic Thiaridae (Mollusca, Gastropoda, Cerithioidea) of the Albertine Rift Valley (Uganda - Congo) and their bearing on the origin and evolution of the Tangayikan thallasoid malacofauna. Hydrobiologia 498:1–83
Van der Beek P, Mbede E, Andriessen P, Delvaux D (1998) Denudation history of the Malawi and Rukawa Rift flanks (East African Rift System) from apatite fission track thermochronology. J Afr Earth Sci 26:363–385
Wagner GA (1972) Spaltspurenalter von Mineralen und natürlichen Gläsern: eine Übersicht. Fortsch Miner 49:114–145
Wagner GA, Van den Haute P (1992) Fission-track dating. Enke, Stuttgart
Wagner M, Altherr R, Van den Haute P (1992) Apatite fission-track analysis of Kenyan basement rocks: constraints on the thermotectonic evolution of the Kenya dome. A reconnaissance study. Tectonophysics 204:93–110
Wallis CS, Valliant WW (2004) Technical report on the Kilembe Mine, Uganda. Prepared for Uganda Gold Mining Ltd. Rosco Postle Associates Inc, Report
Wallner H, Schmeling H (2010) Rift induced delamination of mantle lithosphere and crustal uplift. Int J Earth Sci, doi:10.1007/s00531-010-0521-6
Whittow JB (1966) The landforms of the central Ruwenzori, East Africa. Geogr J 132(1):32–42
Wolf RA, Farley KA, Silver LT (1996) Helium diffusion and low-temperature thermochronometry of apatite. Geochim Cosmochim Acta 60(21):4231–4240
Acknowledgments
We thank the RiftLink research group and our partners from Makerere University for discussion on the Rwenzori geology as well as for the support in the field. We also thank the Uganda National Council for Science and Technology (UNCST) as well as the Uganda Wildlife Authority (UWA) for supporting fieldwork. Furthermore, we would like to thank Peter W. Reiners and Stefan Nicolescu for analytical assistance and valuable discussions. Matthias Hinderer and Martin Wipf are thanked for their constructive suggestions and comments on an earlier version of the manuscript. For providing the computer code HeFTy we would like to express our thanks to Richard A. Ketcham and Raymond A. Donelick, and to Raymond A. Donelick, allowing using Dpar as a kinetic parameter. ASTER GDEM, product of METI & NASA is thanked for providing their images. We furthermore appreciate the support given by Heiko Gerstenberg and the Forschungs-Neutronenquelle FRM II at Garching, TU München. Acknowledgement is given to the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) for their support (GL 182/9-1) and for funding the project (DFG research unit 703). The University Mainz is gratefully acknowledged for a grant supporting a pilot study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Bauer, F.U., Glasmacher, U.A., Ring, U. et al. Thermal and exhumation history of the central Rwenzori Mountains, Western Rift of the East African Rift System, Uganda. Int J Earth Sci (Geol Rundsch) 99, 1575–1597 (2010). https://doi.org/10.1007/s00531-010-0549-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00531-010-0549-7