73-10 Unraveling the magmatic history of Coyote Hills: Mapping and Characterizing basalt flows of a polygenetic shield volcano in the Springerville volcanic field, Arizona

Session: Using Volcanic Deposits to Help Us Understand Volcanic and Magmatic Processes (Posters)

Poster Booth No.: 280

Presenting Author:

Atzi Olivarez

Authors:

Olivarez, Atzi Cruz¹, Kaiser, Jackson Maxwell², Sis-Figueroa, Edwin³, Mnich, Marissa⁴, Van Hoven, Loet⁵

(1) Sonoma State Univ, Rohnert Park, CA, USA, (2) Sonoma State Univ, Clearlake, CA, USA, (3) Sonoma State University, Rohnert Park, California, USA, (4) Sonoma State University, Rohnert Park, CA, USA, (5) Sonoma State Univ, Rohnert Park, CA, USA,

Abstract:

The Springerville volcanic field (SVF) in Eastern Arizona is one of the best mapped basaltic volcanic fields in the world, and with eruptions as young as 50ka, it is still a potentially active system. Situated along the southern margin of the Colorado Plateau, the SVF could offer insights into the eruptive history and evolution of related magmatic systems in the region.  The dominantly monogenetic field contains over 400 cinder cones and two polygenetic shield volcanoes—Blue Ridge Mountain on the western margin and Coyote Hills on the eastern edge.  While nearly the entirety of the SVF has been mapped in detail, Coyote Hills, a 60 km2 shield volcano, represents one of the final pieces in mapping out the eruptive events within the 3000 km2 field. 

43 flows of Coyote Hills were mapped and sampled during a one-month field period, with the assistance of satellite imagery and LiDAR, ranging from small-volume flows confined to individual flanks to a more extensive unit that dominates the east side of the volcano. Field observations of lithologies based upon phenocryst types and abundance were used to distinguish between basalt flows, many of which were alluvium-covered. Flow mineralogy varies from nearly aphyric basalts to olivine-rich and pyroxene-dominated basalt lithologies. Forthcoming detailed petrographic studies and geochemical analysis will classify the flows into quantitative lithologic classes and will assist in making further determinations about the relationships between flows. The magmatic origin of the two polygenetic shield volcanoes within the SVF, the exact age of the volcanoes and the sequencing of the flows of Coyote Hills have been indeterminate since the mapping and study of the SVF began. Compiling the conducted research and additional analysis of collected samples will further increase available information on the shield volcanoes of the Springerville volcanic field and possibly reveal more intricacies of their origin and location within the SVF.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10578

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