Deterioration of Tropical Stone Culture - Sri Lankan experience

Abstract

Sri Lanka is one of the tropical countries in the v,orld v'ith u rich ancienl stone culture. Exislence of stone monumenls and sailptures v,hic:h are presentlv naked, express an evolttlion of amazing ancient stone industry,. Research int,estigalions done cluring the lasl 7 years inJbr the use of advance quarrying techniques in ancient stone industry,. lt fuuher reveals that almost all rhe stone monuments and sculptures ure made up oJ'Gneisses antl Marble of Proterozoic metamorphic roc'ks. ,lclvonce rechnolagical understanding of slotte materials in selecting, Etarrying and carving is speciJically ohserved. Most of the stone heritag,e of the country is under threat of deterioration. Those in the World Heritage Sites ttf Arutradhapura, Polonnaruwa, Sigiriya and Kandy show highly specific cleterioralion potlerns caused b1' tr1pical climatic varialions and clistinctive local geolog,'. The identiJied deterioration palterns are dominqted by eliscoloration, flaking, fragmenlation, splitting, salt oystullization and dissolution. Biological weatheringmainly by lichen grov'ths seems to be a silent agent and it removes surface mineralfragments thut rqngefrom 2 to 17 mgwith a meQn oJ'23 mg/1tear fu' weight. Presently conservation activities based on research investigations o'e caruiecl out. A monitoring ancl management planwhere a scientiJic approac:h is included has been proposed.