GSA Connects 2021 in Portland, Oregon

Paper No. 170-3
Presentation Time: 2:05 PM


DALLEGGE, Todd, Department of Earth and Atmospheric Sciences, University of Northern Colorado, Campus Box 100, Greeley, CO 80639, DEMKO, Timothy Michael, Goodyear, AZ 85338 and ROZS, Lou, Phoenix, AZ 85045

A world class deposit awaits the explorationist on the Colorado Plateau of northeastern Arizona. Helium was first discovered in the 1950s and later produced in the 1960s at Pinta Dome, near Holbrook, AZ. The Pinta Dome area in the Holbrook Basin has produced >10.2 BCF of helium gas to date and continues to produce from 10 active wells. The St. John CO2 Field produces helium from a large 3-way, faulted, anticlinal dome just north of Springerville, AZ. Helium is also associated with several small oil fields in the Paradox Basin in the northeastern corner of the state on Navajo Nation lands.

Arizona has all the right conditions for helium accumulation; older uranium and thorium bearing rocks near the surface, excellent seals for traps, a tectonically stable area, and younger volcanic activity. The source for the 4He has been isotopically fingerprinted to the radioactive decay of existing U- and Th-bearing sediments with a very minor amount of 4He from mantle sources (<3%). Helium gases are entrained with migrating gases from volcanic activity, mantle degassing, and petroleum generation. Northeast AZ is unique in that it has three types of carrier gases. Helium is associated with N2-rich fields within the center of the Holbrook Basin, CO2-rich St. John Field in the SE corner of the greater Holbrook Basin, and with hydrocarbon accumulations at Dineh-bi-Keyah Field in northeast AZ. Helium concentrations range from less than 1% at St. Johns Field, 4-12% near the center of the Holbrook Basin, and 4-7 % in northeastern AZ. Helium accumulations are found in the Shinarump Conglomerate, Coconino and McCracken Sandstones, Supai Group, Granite Wash, and older Paleozoic and Precambrian formations within structural traps below evaporite and shale seals.

The Arizona State Land Department manages over 1.27 million acres of subsurface mineral rights in the greater Holbrook Basin area. Currently, over 0.57 million acres of State Trust land are leased by 19+ operators. Leasing active is at a fast past as operators scramble to acquire a favorable acreage position. Interspersed with the state acreage are BLM, BIA, and National Forest mineral rights along with millions of acres of private subsurface minerals. The use of helium is growing significantly while worldwide sources are dwindling fast. With the BLM selling off the Federal Helium Reserve, demand has driven prices up significantly. Arizona has high helium concentrations at relatively shallow depths (<5000 ft), so the race is on to establish future sources of production.