Mokelumne Hill domes
Mokelumne Hill domes
Pliocene
Consists of five volcanic domes located in the western Sierra foothills near Mokelumne Hill and Jackson. The domes consist of porphyritic hornblende biotite dacite, hornblende dacite, and porphyritic hornblende rhyodacite that intrude the Mehrten Formation fluvial strata (part of map unit aca) and are depositionally overlain by the youngest Mehrten Formation strata (e.g., Rose, 1959; Turrin, 1982; Bartow, 1979). Turrin (1982) reported the most recent K-Ar ages for the domes, which range from 4.73 ± 0.16 Ma (Golden Gate Hill dome) to 3.73 ± 0.29 Ma (Hamby dome).