Download At the bottom of the sea 600 million years ago.

At the bottom of the sea 600
million years ago.
600 million years ago the materials
of Malpica-Tui unit (UMT) were
situated at the bottom of the sea
between
two
big
continents,
Gondwana and Laurasia. It was the
beginning of the Varisca orogeny,
Modificado de Diez Fernández, R. Evolución estructural y
cinemática de una corteza continental subducida: la unidad de
Malpica-Tui. 2010. Salamanca
as it was named. During this period
the materials of Gondwana were
accumulated on the ocean to form sedimentary rocks. During Varisca
orogeny, these stones suffered changes of pressure and temperature, that
is to say, suffered metamorphism. On the beach of Aviño we can see the
footprints of this process on the materials.
Beo´s
rock
doesn´t show
the effects of
a
pressure
and
temperature
increase.
Two images of shale, a type of
metamorphic rock, from Aviño´s
beach. Schist are formed when
they undergo a significant
pressure
and
temperature
increase.
Both are gneiss, metamorphic rocks
formed by a pressure increase and
temperature close to melting.
 Right. Gneiss of Ponteceso. Made
from a sedimentary rock.
 Left. Gneiss of Barizo. Made from an
igneous rock.