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