The Bahía Mansa Metamorphic Complex (Spanish: ''Complejo Metamórfico Bahía Mansa'', CMBM), also known as the Western Series, is a group of
geologic formations
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...
in the
Chilean Coast Range
The Chilean Coastal Range () is a mountain range that runs from north to south along the Pacific Ocean, Pacific coast of South America parallel to the Andes, Andean Mountains, extending from Morro de Arica in the north to Taitao Peninsula, where ...
in southern
Chile
Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
that have been transformed by heat and pressure (a process called
metamorphism
Metamorphism is the transformation of existing Rock (geology), rock (the protolith) to rock with a different mineral composition or Texture (geology), texture. Metamorphism takes place at temperatures in excess of , and often also at elevated ...
). It includes
pelitic schist
Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a l ...
s (layered rocks from mud or clay),
metagreywackes (hardened sandy sediments altered by metamorphism), and
mafic
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...
metavolcanics
(dark-colored rocks from ancient ocean floors). The complex is named after
Bahía Mansa, a nearby coastal bay.
References
Lithodemic units of Chile
Geology of Araucanía Region
Geology of Biobío Region
Geology of Los Ríos Region
Geology of Los Lagos Region
Metamorphic complexes
Geology of the Chilean Coast Range
Coasts of Los Ríos Region
Coasts of Los Lagos Region
{{Geology of Chile