Pahoehoe and a'a lavas are both represented, along with well-developed lava tube systems. These types of features are also present in other, apparently-older flows, although in some cases are obscured by erosion. Tectonic setting and Geochemistry The Zuni-Bandera volcanic field volcanism occurs along the Jemez lineament, a zone where the earth's crust appears to be weak. Alkaline basalts have a higher proportion of elements K and Na relative to Si than tholeiite basalt. In many cases, tholeiite and alkaline basalts are found in different tectonic setting, but in the case of the Zuni-Bandera volcanic field, they occur together.
Visible crystals observed in the basalts includes small olivine, plagioclase feldspar and pyroxene.
Perry et al. Menzies et al. The ages of lava flows in the Zuni-Bandera volcanic field has been difficult to determine due to the composition of the lava flows. A summary of flow ages is given below. For details on the dating techniques or ages, see the listed references.