Tectonic Imprints of the Hazara Kashmir Syntaxis on the Mesozoic Rocks Exposed in Munda,Mohmand Agency,Northwest Pakistan

Two well-developed mesoscopic folds, D_2 and D_3, which postdate the middle amphibolite metamorphism, were recognized in the western hinterland zone of Pakistan. NW–SE trending D_2 folds developed during NE–SW horizontal bulk shortening followed by NE–SW trending D_3 folds, which developed during SE–NW shortening. Micro- to mesoscopically the NW–SE trending S2 crenulation cleavage, boudins and mineral stretching lineations are overprinted by D_3. The newly established NW–SE trending micro- to mesoscopic structures in Munda termed D_2, which postdated F_1/F_2, is synchronously developed with F3 structures in the western hinterland zone of Pakistan. We interpret that D_2 and D_3 folds are counterclockwise rotated in the tectonic event that has evolved the Hazara Kashmir Syntaxis after the main phase Indian plate and Kohistan Island Arc collision. Chlorite replacement by biotite in the main matrix crenulation cleavages indicates prograde metamorphism related with D_2. The inclusion of muscovite and biotite in garnet porphyroblasts and the presence of staurolite in these rocks indicate that the Barrovian metamorphic conditions predate D_2 and D_3. We interpret that garnet, staurolite and calcite porphyroblasts grew before D_2 because the well developed S2 crenulation cleavage wraps around these porphyroblasts.     

The hydrology and sediment yield of the Sungai Air Terjun catchment,Penang Hill,Malaysia

Abstract

The hydrology and sediment yield of the relatively undisturbed Sungai Air Terjun catchment on the forested Penang Hill was investigated in 1993–1994. Baseflow accounted for 87.3% of the total runoff, while quickflow comprised 12.7%. The suspended sediment concentration varied from an average concentration of 11.36 mg 1^?1 (range: 0.5–60.5 mg 1^?1) during low flow to an average concentration of 125.5 mg 1^?1 (range: 11–668.7 mg 1^?1) during storms. Suspended sediment transport during storms accounted for as little as 0.69% of the total sediment transport in the driest month, but as much as 52.35% in the wettest month, November 1993. The frequent high-intensity storms on the hill account for the removal of sediment from the hill. Natural disturbances, such as both landslides and human interference, affect the availability of sediment and thus influence variations in sediment output.