River terraces

The criticisms of these results centre on the provenance of the dated faunal material, and the U uptake models employed by Swisher III et al.(1996). In a reply to the paper, Grun and Thome (1997) suggest the river terrace where the material was found had been reworked many times, mixing older with younger material, and that the state of preservation between the hominid remains and the faunal remains was sufficiently different to suggest they had fossilized in a different environment. In addition, they doubt whether the U uptake models employed are appropriate. In the future, direct dating of the hominid remains themselves will address the first problem, a more sophisticated U uptake model would be required to address the second. 

Phosphate sorption by natural hematites. Eur. J. Soil Sd. 45 45—51 Torrent, J. Schwertmann, U. Schulze, D.G. (1980) Iron oxide mineralogy of some soils of two river terrace sequences in Spain. Geoderma 23 191-208... 

Pavich M. J., Brown L., Harden J., Klein J., and Middleton R. (1986) °Be distribution in soils from Merced River terraces, California. Geochim. Cosmochim. Acta 50, 1727-1735. 

Limestone cave levels within the Dukes system in the Buchan district of East Gippsland in Victoria, southeastern Australia (Fig. 1) can be correlated with a series of three river terraces in the valley of the Buchan River (Webb et al., 1992). Both caves and terraces are thought to have developed in the Pleistocene, because uranium series dating of speleothems in this system gives ages of more than 350,000 years, and perhaps greater... 

Thus the development of the lowest epiphreatic cave level may have been contemporaneous with or pre-date the sediment deposition. This indicates that even the lowest cave level (and the river terrace with which it is correlated) formed in the mid-Pleistocene, or earlier. The sea level and climatic fluctuations of the late Pleistocene, responsible for the bulk of Northern Hemisphere karst geomorphology, have left little discernible trace in the Buchan area (Webb et al., 1992). 

Webb, J. A., Fabel, D., Finlayson, B. L., Ellaway, M., Li Shu, and Spiertz, H.-P., 1992, Denudation chronology from cave and river terrace levels the case of the Buchan Karst, southeastern Australia, Geol. Mag. 129 307-317. 

Pena, F. and Torrent, J., 1984. Relationships between phosphate sorption and iron oxides in alfisols from a river terrace sequence of Mediterranean Spain. Geoderma, 33 283-296. 

River terraces are also developed by rejuvenation. In the lower course of a river, uplift leads to the river cutting into its alluvial plain. The lateral and downstream migration of meanders means that a new flood plain is formed but very often paired alluvial terraces, representing the remnants of the former flood plain, are left at its sides (Fig. 3.17). 

River terrace deposits are similar in character to those found in river channels. The pebbles of terrace deposits may possess secondary coatings due to leaching and precipitation. These are frequently of calcium carbonate that does not impair the value of the deposit, but if they are siliceous, then this could react with alkalies in high-alkali cements and therefore could be detrimental to concrete. The longer the period of post-depositional weathering to which a terrace deposit is subjected, the greater is the likelihood of its quality being impaired. 

The disaster of liquefaction and ground deformation (seismic subsidence) is mainly in the river terraces, river deltas, alluvial plains and... 

The surface powerhouse (SPH-1) was selected on the river terrace (El. 592.0 m) present in the upstream keeping the same tail water level to avoid head loss. A number of shear zones mentioned above are likely to intersect the surge shaft and penstock tunnels. Two holes (BH-2 and BH-4) were drilled where rock was encountered at 23 m and 46 m depths, respectively. 

---