| Autor: |
Genser, Hugo, Mehl, Johannes |
| Zdroj: |
Zeitschrift für Geomorphologie; December 1977, Vol. 21 Issue: 4 p431-444, 14p |
| Abstrakt: |
Karst pipes of large dimensions are found in siliceous sedimentary rocks in Brazil and Venezuela. The holes are mainly cylindrical and are attributed to subsurface solution of an assumed soluble formation. Two possibilities are considered: either carbonate rocks (marble series in the Precambrian basement), or alternatively soluble components (such as feldspar or clay) within a thick conglomerate sequence. In addition there are illuvial mechanisms that could leach out material at the watertable. This “subrosion” (as distinct from “piping” and “suffosion”) process would appear to occur whereever tectonic structural effects favor a concentration of groundwater flow in the subsurface. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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