are not clearly visible in the crystalline spectrum.

To the West, a Jurassic structure and a crystalline base covered with sandstone.

Its narrow valley sits on the crystalline foundation that makes up the backbone of the entire island.

Central and Southern Alps with crystalline rock, consisting mainly of granites and gneisses

Its depth gradually decreases from about 2.5 km in the west to 0.8 km in the east.

The hydrogeological characterization study of crystalline rocks was performed in 1991 – 1993 and included the following steps:

But there is not a single one in France, even though it is a country well-endowed geologically, possessing several crystalline basement zones.

Directly below, you have fossil-free crystalline basement rock, which formed about a billion or more years ago.

The majority of the recorded earthquakes occurred at a depth of around 8 km, most probably in the crystalline bedrock.

The crystalline basement (983.30-1007 m) consists of highly metamorphosed, partly migmatic gneisses and an aplite dyke.

The borehole reached a final depth of 1007 m, passed through the entire Mesozoic sediment sequence and finally encountered the crystalline basement.

Crystalline basement Lower Precambrian This system comprises the North Gabon massif, the Chaillu massif and the Mayombe range.

This corresponds to the type of flow-paths most commonly encountered in the basement of Northern Switzerland.

Rainwater seeps through microscopic fault lines in the region of Auvergne and makes its way through a crystalline basement.

They all are integrated in this report which represents a complete background information on the hydrogeology of crystalline rocks in the basement of Northern Switzerland.