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Mizarela Lithological Contact
Schists and granites are side by side
This is certainly one of the geosites of the Arouca Geopark where the macroscopic characteristics are best observed, which allows us to distinguish "xistento" rocks from granitoid rocks, since they are presented side by side, due to the abrupt lithological contact of approximate NW direction -SE and inclined close to 90 degrees. It is considered an excellent place for the exercise of geological mapping techniques.
The granite is in the form of a residual relief, projecting from the landscape, as, incidentally, happens all over the plateau of the Serra da Freita. This rock called granite from the Freita mountain range is a tectonic magmatic rock, leuco the mesocrite, of phanerite texture and medium grain. Despite being described as a two-mica granite, interestingly, in this place, there is a clear dominance of the moscovite in relation to the biotite.
On the other hand, the rocks known as 'xistentas' correspond mainly to micaxists, affected by regional metamorphism of medium degree, where it is possible to observe a schist NW-SE to WSW-ESE, subvertical. In the biotytic micaxists, staphylococcal and andalusite porphyroblasts are also present, also showing some silimanite (fibrolite), the latter being only observed under the microscope, but whose presence indicates that the rocks are in the silimanite zone of the regional metamorphism. The crystals of staurolite reach to dimensions of several centimeters and sometimes they appear maclados.
Useful information
Mizarela - União de Freguesias de Albergaria da Serra e Cabreiros
916 metros
40.864772 | -8.285128
Contacto Litológico da Mizarela
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Other geosites