El Rojo Sur

20°50′S 68°37′W / 20.833°S 68.617°W / -20.833; -68.617[1] El Rojo Sur is a monogenetic volcano in the Andes,[1] in the form of a cone.[2]

It is similar to El Rojo Norte 260 kilometres (160 mi) farther north.[1] A mafic andesite lava flow was erupted from the 100 metres (330 ft) high cone that also features red scoria. Ages obtained by potassium-argon dating are 2.93±0.13, 3.4±0.4 and 3.23±0.12 mya.[3]

Rojo Sur erupted undifferentiated mafic magmas. Its lead isotope composition is different from the composition of that segment of the Andes, being non-radiogenic. This isotope signature may be the effect of assimilation of deeper basement rocks during magma formation.[2] In addition, the magmas are rich in incompatible elements.[4]

  1. ^ a b c Cite error: The named reference Wigger1994 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference WornerMoorbath1992 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference WornerHammerschmidt2000 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference WornerEscobar1992 was invoked but never defined (see the help page).