Jon's last geologic map, "Geologic map of the Cross Roads 7.5' Quadrangle and the southern part of the Gene Wash 7.5 Quadrangle," was officially released on Friday as an AZGS publication and it was formally dedicated to Jon in recognition to the understanding of the geology of Arizona.
Under Jon Spencer's leadership, the AZGS mapping program became one of the premier efforts in the country, often held up as a model for other states. [Bottom, Jon listens to colleagues commenting on his contributions. A framed copy of Cross Roads map dedicated to him stands at the right. In front of him is a 1 to 12 scale photo of him in the field, mounted on cardboard, with multiple copies offered by Brian Gootee to the other mapping geologists to take with them to the field, so they also have Jon along with them.]
Citation: Spencer, J.E. and others, 2015, Geologic map of the Cross Roads 7.5' Quadrangle and the southern part of the Gene Wash 7.5 Quadrangle, La Paz County, Arizona, and San Bernardino County, California. Arizona Geological Survey Digital Geologic Map DGM 111, 1 map sheet, 1:24,000 scale.