Fragões das Penhas tor and castle-koppie (Geosite), Seia

In a typical granite weathering landscape, the Fragões das Penhas Douradas, located at a summit position south of Vale do Rossim, are majestic granite outcrops that protrude above de sands that make up the weathering mantle. Its forms are controlled by the fracture patterns of granite, thus presenting a geometric organization. The tor and castle koppie that we observe, have their origin in the deep chemical weathering of the granite during a time when the climate was hotter and wetter, before the mountain’s main uplift. With the increase in the slope’s angle and degradation of the vegetation cover, the weathering mantle was slowly eroded, exposing the more resistant rock core, observed nowadays at the surface. The fractures were the main zones for infiltration in the weathering mantle, controlling deep weathering and the present day landforms.

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