Leaving the south rim of the Grand Canyon, we planned a long drive to Gallup, New Mexico. Along the way we stopped in at the Wupatki National Monument. This is a old Anasazi site with several ruins set amongst some recent volcanic activity — indeed, it was the volcanic enrichment of the soil that made the site an attractive farming location for the Anasazi. The people remained in the area during the volcanic activity. The ruins were left behind when the area was abandoned about 1215 A.D.

The volcanic activity consisted of two major lava flows, one in 1064-65 A.D., another in 1180 A.D. and the more or less continuous building of the Sunset Crater cinder cone over the interval. The final eruptions produced iron oxides and sulphur compounds that colour the summit providing the ‘sunset’ effect.