Prediction of weathering development in metarhyolites of the Ilgın (Konya) area, SW Turkey

Authors : Erkan BOZKURTOĞLU, Şenel ÖZDAMAR, Hatice Ünal ERCAN

Pages : 264-276

Doi:10.3906/sag-1211-18

View : 17 | Download : 4

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Fresh to weathered metarhyolites crop out in the Ilgın insert ignore into journalissuearticles values(Konya); area of the Afyon-Bolkardağ Zone. Determination of the development of weathering was studied by physical insert ignore into journalissuearticles values(i.e. specific gravity, dry unit weight, saturated unit weight, porosity, void ratio, and degree of saturation by weight); and mechanical insert ignore into journalissuearticles values(i.e. point load); properties and the \`point rock change value\` insert ignore into journalissuearticles values(RCVp); and \`point rock change ratio\` insert ignore into journalissuearticles values(RCRp); values of the metarhyolite rock samples. The samples were classified in 3 groups insert ignore into journalissuearticles values(i.e. A, B, and C); representing degree of weathering from weathered to fresh rocks based on their RCVp and RCRp values. The K2O values are 7.09 wt.%, 8.62 wt.%, and 8.75 wt.% and the matrix ratios are 60%-70%, 50%-60%, and 20%-25% for groups A, B, and C, respectively. The RCVp and RCRp values of the studied samples range between 0.952 and 0.99 and 4.973% and 0.989%, respectively. Calculations show that metarhyolites will be completely changed by weathering at a 9.01% RCRp value according to metarhyolite alkali values varying in the 8.12%-9.40% range, with the average value being 8.89%. At the end of the rock change processes by weathering, the rocks remain chemically as metarhyolite, while their physico-mechanical properties and mineralogical compositions change to become soil. The average K-Ar ages vary between 60.4 ± 0.9 Ma and 64.1 ± 2.00 Ma. The whole-rock alteration can furthermore be predicted by the relationships between the RCRp and K-Ar ages of the 3 groups, which indicate that the rocks will be fully altered in the next 4.593 and 9.393 Ma. The whole-rock alteration will be completed for group A rocks in 4.6 Ma, for group B rocks in 7.2 Ma, and group C rocks in 9.4 Ma, provided that all the weathering agents take effect under the same conditions across the area.
Keywords : Ilgın, metarhyolite, physico mechanical properties, weathering, point rock change value, point rock change ratio, K Ar ages, whole rock alteration