The Cordillera Nevada Caldera lies just west of
the Liquine-Reloncavi line, a major N10°E
strike-slip fault that spans much of the length of the
south- central Chilean volcanic belt. It also lies at the
apex of two segments of a conjugate set of N60°E and
N50°W faults that are at least in part tension
features associated with movement along the
Liquine-Reloncavi Fault. Many of the volcanoes in this
area, including Cordillera Nevada center, the Cordon
Caulle fissures, and Puyehue, have grown along this set
of conjugate faults.
The Cordillera Nevada Caldera is the only known source
of rhyolitic tuff in the southern Andes. The age of the
Cordillera Nevada Caldera is unknown; extensive
glaciation indicates that it is at least 16,000 years
old, and probably 100,000 to 200,000 years old.
Cordon Caulle is a
group of postcaldera silicic vents along WNW-ESE trending
fissures. Some of the Cordon Caulle vents occur within
the Cordillera Nevada Caldera, while others are outside
the caldera (a relation not unlike that of the Inyo domes
and the Long Valley Caldera in California, USA). It is
not known if magma of the Cordon Caulle group is related
to any beneath the Cordillera Nevada Caldera.