Iron oxides in fractured quartz – development and evolution of iron sandstone layers in the Kinshasa area, DR Congo
F. Mees A F , G. Phemba B , P. Lahogue A , E. De Grave C , E. Van Ranst D and C. Mpiana E
+ Author Affiliations
- Author Affiliations
A Department of Geology, Royal Museum for Central Africa, Belgium.
B Centre de Recherches Géologiques et Minières, Kinshasa, DR Congo.
C Department of Physics and Astronomy, Ghent University, Ghent, Belgium.
D Department of Geology, Ghent University, Ghent, Belgium.
E Départment des Sciences de la Terre, Université de Kinshasa, Kinshasa, DR Congo.
F Corresponding author. Email: florias.mees@africamuseum.be
Soil Research 56(5) 518-525 https://doi.org/10.1071/SR18062
Submitted: 25 February 2018 Accepted: 25 April 2018 Published: 6 July 2018
Abstract
Quartz grains in an iron sandstone layer in near-surface sandy deposits at Kasangulu, south of Kinshasa, DR Congo, are marked by the presence of iron oxides in subparallel horizontal cracks within the sand grains. This exceptional feature was investigated to understand its origin and paleoenvironmental significance. Based on thin section observations, supplemented by Mössbauer spectroscopy results and other data, the occurrence of filled subparallel cracks is attributed to iron oxide remobilisation following crack opening within an iron-oxide-cemented sand intercalation that became exposed through erosion, whereby crack opening is related to surface temperature fluctuations. The development of filled crack occurrences of this type requires a period of surface exposure, implying that their presence is indicative of the position of former surface levels. A macroscopically similar iron sandstone layer at another locality in the Kinshasa area, lacking filled cracks, provides indications for both surface exposure and cement type as factors in their development.
Additional keywords: diagenesis, fracturing, iron sandstone, quartz, surface exposure.
References
Anders MH, Laubach SE, Scholz CH (2014) Microfractures: a review. Journal of Structural Geology 69, 377–394.| Microfractures: a review.Crossref | GoogleScholarGoogle Scholar |
Bloss FD, Gibbs GV (1963) Cleavage in quartz. The American Mineralogist 48, 821–838.
De Grave E, Chambaere D, Bowen LH (1983) Nature of the Morin transition in Al-substituted hematite. Journal of Magnetism and Magnetic Materials 30, 349–354.
| Nature of the Morin transition in Al-substituted hematite.Crossref | GoogleScholarGoogle Scholar |
De Ploey J, Lepersonne J, Stoops G (1968) Sédimentologie et Origine des Sables de la Série des Sables Ocre et de la Série des ‘Grès Polymorphes’ (Système du Kalahari) au Congo Occidental. Annales du Musée Royal de l’Afrique Centrale, Sciences Géologiques, 61, 72 p.
England GL, Rasmussen B, Krapez B, Groves DI (2001) The origin of uraninite, bitumen nodules, and carbon seams in Witwatersrand gold-uranium-pyrite ore deposits, based on a Permo-Triassic analogue. Economic Geology and the Bulletin of the Society of Economic Geologists 96, 1907–1920.
| The origin of uraninite, bitumen nodules, and carbon seams in Witwatersrand gold-uranium-pyrite ore deposits, based on a Permo-Triassic analogue.Crossref | GoogleScholarGoogle Scholar |
Eswaran H, Sys C, Sousa EC (1975) Plasma infusion. A pedological process of significance in the humid tropics. Anales de Edafología y Agrobiología 34, 665–674.
Gasparini E, Tarantino SC, Ghigna P, Riccardi MP, Cedillo-González EI, Siligardi C, Zema M (2013) Thermal dehydroxylation of kaolinite under isothermal conditions. Applied Clay Science 80-81, 417–425.
| Thermal dehydroxylation of kaolinite under isothermal conditions.Crossref | GoogleScholarGoogle Scholar |
Grønvold F, Stolen S, Svendsen SR (1989) Heat capacity of α quartz from 298.15 to 847.3 K, and of β quartz from 847.3 to 1000 K – transition behaviour and revaluation of the thermodynamic properties. Thermochimica Acta 139, 225–243.
| Heat capacity of α quartz from 298.15 to 847.3 K, and of β quartz from 847.3 to 1000 K – transition behaviour and revaluation of the thermodynamic properties.Crossref | GoogleScholarGoogle Scholar |
Gualtieri AF, Venturelli P (1999) In situ study of the goethite-hematite phase transformation by real time synchrotron powder diffraction. The American Mineralogist 84, 895–904.
| In situ study of the goethite-hematite phase transformation by real time synchrotron powder diffraction.Crossref | GoogleScholarGoogle Scholar |
Guillocheau F, Chelalou R, Linol B, Dauteuil O, Robin C, Mvondo F, Callec Y, Colin JP (2015) Cenozoic landscape evolution in and around the Congo Basin: constraints from sediments and planation surfaces. In ‘Geology and Resource Potential of the Congo Basin’. (Eds MJ de Wit, F Guillocheau, MCJ de Wit) pp. 271–313 (Springer: Berlin)
Gunzburger Y, Merrien‐Soukatchoff V (2011) Near‐surface temperatures and heat balance of bare outcrops exposed to solar radiation. Earth Surface Processes and Landforms 36, 1577–1589.
| Near‐surface temperatures and heat balance of bare outcrops exposed to solar radiation.Crossref | GoogleScholarGoogle Scholar |
Hajpál M, Török A (2004) Mineralogical and colour changes of quartz sandstones by heat. Environmental Geology 46, 311–322.
| Mineralogical and colour changes of quartz sandstones by heat.Crossref | GoogleScholarGoogle Scholar |
Hœrlé S (2006) Rock temperatures as an indicator of weathering processes affecting rock art. Earth Surface Processes and Landforms 31, 383–389.
| Rock temperatures as an indicator of weathering processes affecting rock art.Crossref | GoogleScholarGoogle Scholar |
Horai K, Simmons G (1969) Thermal conductivity of rock-forming minerals. Earth and Planetary Science Letters 6, 359–368.
| Thermal conductivity of rock-forming minerals.Crossref | GoogleScholarGoogle Scholar |
IUSS Working Group WRB (2015) ‘World reference base for soil resources 2014’, Update 2015. World Soil Resources Reports No. 106. (FAO: Rome)
Kerr A, Smith BJ, Whalley WB, McGreevy JP (1984) Rock temperatures from southeast Morocco and their significance for experimental rock-weathering studies. Geology 12, 306–309.
| Rock temperatures from southeast Morocco and their significance for experimental rock-weathering studies.Crossref | GoogleScholarGoogle Scholar |
Kosinski JA, Gualtieri JG, Ballato A (1991) Thermal expansion of alpha quartz. Proceedings of the 45th Annual Symposium on Frequency Control, pp. 22–28. (Institute of Electrical and Electronics Engineers: Piscataway)
Kündig W, Bömmel H, Constabaris G, Linquist RH (1966) Some properties of supported small α-Fe2O3 particles determined with the Mössbauer effect. Physical Review 142, 327–333.
| Some properties of supported small α-Fe2O3 particles determined with the Mössbauer effect.Crossref | GoogleScholarGoogle Scholar |
Little IP, Armitage TM, Gilkes RJ (1978) Weathering of quartz in dune sands under subtropical conditions in eastern Australia. Geoderma 20, 225–237.
| Weathering of quartz in dune sands under subtropical conditions in eastern Australia.Crossref | GoogleScholarGoogle Scholar |
Majzlan J, Lang BE, Stevens R, Navrotsky A, Woodfield BF, Boerio-Goates J (2003) Thermodynamics of Fe oxides: Part I. Entropy at standard temperature and pressure and heat capacity of goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and maghemite (γ-Fe2O3). The American Mineralogist 88, 846–854.
| Thermodynamics of Fe oxides: Part I. Entropy at standard temperature and pressure and heat capacity of goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and maghemite (γ-Fe2O3).Crossref | GoogleScholarGoogle Scholar |
McGreevy JP (1985) Thermal properties as controls on rock surface temperature maxima and possible implications for rock weathering. Earth Surface Processes and Landforms 10, 125–136.
| Thermal properties as controls on rock surface temperature maxima and possible implications for rock weathering.Crossref | GoogleScholarGoogle Scholar |
Molaro JL, McKay CP (2010) Processes controlling rapid temperature variations on rock surfaces. Earth Surface Processes and Landforms 35, 501–507.
Peel RF (1974) Insolation weathering: some measurements of diurnal temperature changes in exposed rocks in the Tibesti region, Central Sahara. Zeitschrift für Geomorphologie, Supplementband 21, 19–28.
Pye K (1983) Formation of quartz silt during humid tropical weathering of dune sands. Sedimentary Geology 34, 267–282.
| Formation of quartz silt during humid tropical weathering of dune sands.Crossref | GoogleScholarGoogle Scholar |
Roth ES (1965) Temperature and water content as factors in desert weathering. The Journal of Geology 73, 454–468.
| Temperature and water content as factors in desert weathering.Crossref | GoogleScholarGoogle Scholar |
Service Géologique de la République du Congo (1963) Feuille Léopoldville (S. 5/15), Carte Géologique du Congo, 1/200,000. (Service Géologique de la République du Congo: Kinshasa)
Stoops G (2003) ‘Guidelines for analysis and description of soil and regolith thin sections.’ (Soil Science Society of America: Madison)
Strasser A, Bernier P (1988) Early diagenetic ferruginous cementation in the intertidal zone: example from Noirmoutier Island, France. Oceanologica Acta 11, 353–357.
van Reeuwijk LP (2002) ‘Procedures for soil analysis’, 6th edn. (ISRIC: Wageningen)
Vandenberghe RE, De Grave E, de Bakker PMA (1994) On the methodology of the analysis of Mössbauer spectra. Hyperfine Interactions 83, 29–49.
| On the methodology of the analysis of Mössbauer spectra.Crossref | GoogleScholarGoogle Scholar |
Waragai T (1998) Effects of rock surface temperature on exfoliation, rock varnish, and lichens on a boulder in the Hunza Valley, Karakoram Mountains, Pakistan. Arctic and Alpine Research 30, 184–192.
| Effects of rock surface temperature on exfoliation, rock varnish, and lichens on a boulder in the Hunza Valley, Karakoram Mountains, Pakistan.Crossref | GoogleScholarGoogle Scholar |
Warke PA, Smith BJ (1998) Effects of direct and indirect heating on the validity of rock weathering simulation studies and durability tests. Geomorphology 22, 347–357.
| Effects of direct and indirect heating on the validity of rock weathering simulation studies and durability tests.Crossref | GoogleScholarGoogle Scholar |
