The geology of
San Marino reflects a complex and chaotic arrangement of
allochthon
upright=1.6, Schematic overview of a thrust system. The hanging wall block is (when it has reasonable proportions) called a nappe. If an erosional hole is created in the nappe that is called a window (geology)">window. A klippe is a solitary out ...
formations, shifted into the region from the west as Liguride nappes during the
Miocene Tortonian uplift.
Olistostrome slump layers are exposed throughout the south of the country. Tortonian sandstone and
limestone form the
San Marino Series, where the town of San Marino is built. In 1977, two geologists, Bartolini and Gittoni, published research on
argillite sediment in the country. Nardi and Nardi, a similar pair of geologists published their findings in 1975 of
gypsum and sulfide formations related to the
Messinian salinity crisis—a massive desiccation of the Mediterranean which left thick salt deposits. In the north, San Marino is overlain by
Pliocene marine sediments.
References
{{Europe topic, Geology of