Jemez Lineament

rdf:langString Jemez Lineament

rdf:langString The Jemez Lineament is a chain of late Cenozoic volcanic fields, 800 kilometers (500 mi) long, reaching from the Springerville and White Mountains volcanic fields in East-Central Arizona to the Raton-Clayton volcanic field in Northeastern New Mexico. The lineament was long interpreted as a hotspot trace (Raton hotspot) due to its resemblance in length and direction to the Yellowstone hot spot trace, but there is no systematic progression in age along the trace and it is now interpreted as a hydrous subduction zone scar. This formed about 1.7 billion years ago, when oceanic crust was subducting under what was then the southern edge of North America. The arrival of a large island arc in the subduction zone shifted subduction further south, leaving remnants of oceanic crust at the top of the Earth's mantle along the former subduction zone. These are rich in hydrous minerals that lower the melting temperature of the rock containing them. This hydrous subduction scar now separates basement rock of the Yavapai-Mazatzal transition zone from the Mazaztl Province proper.