Abstract
The Karoo Dolerite Suite in South Africa is an important source of road construction aggregates both as natural gravel aggregate and as a crushed rock aggregate. The reason for this is the wide distribution of the suite throughout the Karoo Supergroup, which is generally lacking in quality aggregate lithologies. The Karoo Dolerite Suite can however, despite being a single geological unit, be of significantly variable petrography mainly due to the very large area (>500,000 km2) and wide variety of lithologies into which these hypabyssal rocks were intruded. The nature of relatively small hypabyssal intrusions also leads to significant variations in texture and primary and secondary mineralogy within one intrusion. Material prospecting campaigns tend to underestimate such variations due to the fact that all intrusions are assigned to this one geological unit. Such generalizations result in inadequate sampling and subsequent inadequate characterization of potential source materials. This paper discusses the differences in petrography of eight different quarries located in different country rock lithologies and in a variety of climatic regions ranging from arid to moist sub-humid. The observed differences are not linked to variations in intrusion settings (primary variations) or climatic regions (secondary variations). The significance of the observed variations on the properties and performance of the aggregates is however high as illustrated in case studies of some inadequately characterized aggregates that have been utilized only to become problem materials.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
ASTM (2002) Absorption and bulk specific gravity of dimension stone (C97–96). In: ASTM 2002 annual book of ASTM standards, Section 4, v. 04.07, ‘Dimension stone’, American Society for Testing and Materials, Philadelphia, pp 1–3
Chevallier L, Woodford AC (1999) Morpho-tectonics and mechanism of emplacement of the dolerite rings and sills of the western Karoo, South Africa. S Afr J Geol 102:43–54
Duncan RA, Marsh JS (2006) The Karoo igneous province. In: Johnson MR, Anhaeusser CR, Thomas RJ (eds) The geology of South Africa. Geological Society of South Africa, Johannesburg, pp 501-520
Duncan RA, Hooper PR, Rehacek J, Marsh JS, Duncan AR (1997) The timing and duration of the Karoo igneous event, southern Gondwana. J Geophys Res 102(B8):18127–18138
Harris WG, White GN (2008) X-ray diffraction techniques for soil mineral identification. In: Ulery A, Drees R (eds) Methods of soil analysis: Part 5 e mineralogical methods. Soil Sci Soc Am, Madison, pp 81–115
ISRM (1985) International Society of rock mechanics commission on testing methods, suggested method for determining point load strength. Int J Rock Mech Min Sci Geomech Abstr 22:51–60
Kilic R (1995) The degree of alteration and geomechanical properties of diabase in the Ankara Ophiolitic Mélange, Turkey. Environ Eng Geosci 1(3):341–351
Le Roux A, Reid DR (1978) Geochemistry of Karoo dolerite sills in the Clavinia district, Western Cape Province, South Africa. Contrib Miner Petrol 66:351–360
Leyland R, Paige-Green P, Momayez M (2013) Development of the road aggregate test specifications for the modified ethylene glycol durability index for basic crystalline materials. J Mater Civ Eng 10.1061/(ASCE)MT.1943-5533.0000946 (Sep. 20, 2013)
Orr C (1979) Rapid weathering dolerites. Civil Eng S Afr 161–167
Paige-Green P (2007) Durability testing of basic crystalline rocks and specification for use as road base aggregate. Bull Eng Geol Environ 66:431–440
Richardson SH (1979) Chemical variation induced by flow differentiation in an extensive Karoo dolerite sheet, southern Namibia. Geochim Cosmochim Acta 43:1433–1441
Van Rooy JL, Nixon N (1990) Mineralogical alteration and durability of Drakensberg basalts. S Afr J Geol 93(5/6):729–737
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2015 Springer International Publishing Switzerland
About this paper
Cite this paper
Leyland, R. (2015). Some Variations in Petrography of South African Karoo Dolerites and the Effects Thereof on Aggregate Properties. In: Lollino, G., Manconi, A., Guzzetti, F., Culshaw, M., Bobrowsky, P., Luino, F. (eds) Engineering Geology for Society and Territory - Volume 5. Springer, Cham. https://doi.org/10.1007/978-3-319-09048-1_12
Download citation
DOI: https://doi.org/10.1007/978-3-319-09048-1_12
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-09047-4
Online ISBN: 978-3-319-09048-1
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)