REMEMBERING R. ERNEST ANDERSON: A PIONEER IN BASIN AND RANGE EXTENSIONAL TECTONICS

Recognition of large-scale Tertiary extensional tectonics of the Basin and Range can be credited to Ernie Anderson, iconoclastic and legendary geologist. This session is dedicated to his science and influence on generations of geologists. Ernie had a distinguished career with the USGS beginning with mapping at the Nevada Test Site and Lake Mead areas. His early study of tilted fault blocks bounded by low-angle faults due to spreading above a shallow pluton made him widely recognized with the classic publication ‘Thin-skin distension in Tertiary Rocks of Southeastern Nevada’ (1971). Paradoxically, Ernie spent the last 20 years trying to dispel some of the later research in which disparate low-angle fault segments were linked as evidence of crustal scale detachment faults. Based on intensive field work, he promoted south-directed shortening and westward tectonic escape as important mechanisms for the complex deformation he observed widely and that to him was not easily explained by the detachment fault paradigm. In GSA Special Paper 463, dedicated to his Lake Mead work, he and Sharon Diehl described widespread dissolution fabrics in breccias, suggesting many features interpreted as fault-related were instead caused or strongly altered by fluid flow, dissolution, and collapse. He argued that estimates of extension magnitude could be significantly too large. This hypothesis remains controversial—and that was the wonder of Ernie as a geologist, as he was compelled to think beyond models when his mountain-goat style field-based studies warranted it. He said once: “The older I get, the more I see, the less I understand”. He told us of his Lake Mead quadrangle mapping: “Those are just cartoons”, even while they were excellent maps.

Ernie and Vera moved to Kernville in the southern Sierra, living on the banks of the Kern River with kayaking, rafting, and swimming out the back door. Retiring in 2008, he continued his research on tectonic escape and the influence of dissolution on extension. As a team, they travelled widely, with research-focused adventures to the Italian and Greek Islands, western Mojave Desert, Lake Mead, and lower Colorado River corridor.

Ernie was born on Christmas Day, 1932, and passed away peacefully on June 13, 2020, leaving a gaping hole in his family, the Kernville hamlet, and the greater geologic community.