Petrography and mechanical properties of the Mansehra granite, Hazara, Pakistan
Abstract
Rocks of granitic composition occur in the area around Mansehra (Hazara), Pakistan. These rocks are mostly used as building/ construction materials. In order to study the petrography of these rocks in detail and determine their geotechnical properties, representative samples were collected from different parts of the area. Detailed studies reveal that, compared to granitic rocks from elsewhere in northern Pakistan, the investigated rocks have very low values of compressive strength. This could be due to their older age, coarser texture, unevenness in grain size, deformed/ metamorphosed character and weathered/ altered nature. Therefore, they cannot be recommended for use in the construction of large-scale engineering structures such as tunnels and dams. However, the compressive strength values and Cs/Ts ratios of the studied rocks are high enough for their use as building stones in the construction of railway tracks, bridges, roads, canals, drainages and embankments.
References
Annon, 1979. Classification of soils and rocks for engineering geological mapping, Part-I, rocks and soil materials. Bull. Inst. Ass. Engg. Geol., 19, 364-371.
ASTM, 1982. Standard test methods for water absorption and bulk specific gravity of material building stone. American Society for Testing Material, Philadelphia, Pennsylvania, U.S.A.
Chamberlain, C. P., Zeitler, P. K. and Jan, M. Q., 1989. The dynamics of the suture between the Kohistan island arc and 'the Indian plate in the Himalaya of Pakistan. Jour. Met. Geol., 7, 135-149.
Coward, M. P., Windley, B. E, Broughton, R. D, Luff, I. W., Petterson, M. G., Pudesy, C. J., Rex, D. C. and Asif, K. M., 1986. Collision tectonics in the NW Himalaya. In: Coward, M. P. and Ries, A., eds., Collision Tectonics, Geol. Soc. Spec. Publ. 19, Blackwell Sci. Publs., Lotion, England, 203-219.
Dhir, R.X. & Sanghar C.M., 1973. Relationships between size, deformation and strength for cylindrical specimens loaded in uniaxial compression [Abstr]. J. Int. J. Rock Min. Sci. and Geomech., 10, 692-712.
Din, F., Rafiq, M. and Nisar, M., 1993. Strength. properties of various building stones of NWFP, Pakistan. Geol. Bull. Uni. Peshawar, 26, 119-126.
Gansser, A., 1980. The significance of the Himalayan suture zone. Tectonophysics, 62, 37-52.
Khan, M., Haider, S. and Ahmed, A., 1990. Compressive strength of the various building stones of Peshawar plain, N. W. F. P., Pakistan, Unpubl. M. Sc. thesis, Univ. Peshawar.
Le Fort, Debon, F. and Sonet, J., 1980. The Lesser Himalayan' cordierite granite belt, typology and the age of the pluton of Mansehra, Pakistan. Geol. Bull. Univ. Peshawar, Spec. Issue, 13, 51-62.
Shams, F. A., 1967. Granites of the Mansehra-Amb state area and the associated metamorphic rocks. Unpubl. Ph. D. thesis, Univ. Punjab, Lahore.
Shams, F. A., 1983. Granites of NW Himalayas in Pakistan. In: Shams, F. A., ed., Granites of Himalayas, Karakorum and Hindukush. Inst. Geol. Punj. Univ., Lahore, 7, 45-56.
Treloar, P. J. & Rex, D. C., 1990. Cooling and uplift histories of the crystalline thrust stack of the Indian plate internal zones west of Nanaga Parbat, Pakistan Himalaya. Tectonophysics, 180, 32-349.
Treloar, P. J., Rex, D. C., Guise, P. G., Coward, M. P., Searle, M. P., Windley, B. F., Peterson, M. G., Jan, M. Q. and Luff, I. A., 1989. K-Ar and Ar-Ar geochronolgy of the Himalayan collision in NW Pakistan: constraints on the timing of suturing, deformation, metamorphism and uplift. Tectonics, 8, 881-909.
