Stop 27: Dome D

Dome D

S22 57. 0137 W67 42. 5709

 

Leaving the post-glacial domes behind we then headed back east to Dome D. Dome D is a pre-glacial dome that yields similar ages and compositions to the Purico ignimbrites, and is thought to be the same magma that formed the Purico ignimbrites just degassed. Dome D lavas are crystal-rich containg plagioclase, hornblende, quartz, and biotite in a glassy groundmass, and are ~60% less vesicular than the purico ignimbrite (Schmitt et al., 2001). Mafic enclaves were found in Dome D lavas, which would be expected if Dome D is genetically  related to the Purico ignimbrite.