A stratigraphic section for the Monument consists of very few rock types. Surficial lithology is limited to the basaltic lava flows in all locations except the north end of the monument. It is assumed that the rocks that underlie other parts of the ESRP, such as rhyolite flows, also underlie much of the Monument, though no drilling has been conducted. Unconsolidated sediments primarily include windblown silt (loess) and sand deposits, cinder deposits, alluvium along streams, colluvium at the base of steep slopes, and lacustrine deposits associated with ponds.

Dating methods used in the Monument include mapping field relations, magnetic polarity studies, dendrochronology, radiocarbon analyses, and K-Ar dating. In the past few decades, Kuntz, et al, (1988, 1989, 1989a, 1989b) and Champion, et al, (1989) have achieved detailed mapping of flows and their relationships with one another. The sequence of eruptions deduced from the superposition of volcanic landforms forms the base for other stratigraphic investigations.

The first efforts to determine the age of the lava flows in the Monument utilized dendrochronology (tree ring dating). One of the first attempts involved a limber pine tree known as the "Triple Twist Tree", which was growing in a crack on the North Crater Flow. It can still be seen today, but died back in 1961 and at the time of study already had rotted heartwood. The tree, about 16 inches (40 cm) in diameter, had 1,350 countable rings and was estimated to be 1,500 years old, allowing for the missing heartwood. The lava would be a minimum of 1,650 years old if it is assumed that it took at least 150 years for the soil to accumulate for it to grow in (Stearns, 1963). Dendrochronology is not applicable to the older flows because the trees despite their remarkable longevity are not long-lived enough, but at least tree ring dating helps establish a minimum age for the younger flows.

For a more precise age, absolute dating techniques that employ radioactive decay rates of various elements can be used. The decay of potassium to argon in the basalts of the Monument was analyzed by Armstrong, et al, (1975). The results indicated that the basalts had a K-Ar age of zero million years, or are younger than the minimum datable age for this dating technique, which is approximately 10,000 to 20,000 years for rocks rich in potassium and probably 100-200 ka for SRP basalts. Recently researchers have been collecting samples for Argon 40/39 dating of the older flows.

Carbon-14 dating has been the most successful technique used to date Late Pleistocene and Holocene age flows in the Monument. Because lava flows obliterate nearly all carbon life during the eruptions, sources of carbon for dating are scarce. To find datable carbon for the first radiocarbon investigation, scientists dug beneath the lava flows at the perimeter of the lava field to uncover buried carbonized roots of the plants burned by the flowing lava (Bullard, 1970). What is believed to be sagebrush rootlets were found beneath a pahoehoe flow at the southern edge of the Blue Dragon flow. Analyses of two separate samples resulted in carbon-14 dates of 2,110 ± 90 years BP and 2,050 ± 80 years BP. Based on stratigraphy, it was estimated that this was one of the youngest flows in the COM lava field. Later investigations used both carbon retrieved from digging under the lava and small carbonized pieces of trees collected from tree molds in lava flows. Dating carbon from many localities throughout the Monument lava fields has yielded age dates ranging from approximately 15,000 to 1,700 years BP (Bullard, 1970; Kuntz, et al, 1982). Based on all dating techniques and stratigraphic investigations, it has been determined that COM lava field was formed during at least 8 eruptive periods/episodes between approximately 15,000 years to 2,000 years BP (Kuntz, et al, 1982, 1986, 1988, 1992). Within limits of analytical error, Kings Bowl and Wapi lava fields are contemporaneous and formed about 2,200 years ago.