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Resistant outcrops of Proterozoic volcanic exhalites indicate that the Cleator, AZ, region was once part of a volcanic arc setting. These outcrops are comprised of dark chert; nearby outcrops are comprised of banded iron formation and also are reported to include tourmalinite, a chemical sedimentary rock comprised of precipitated tourmaline.
PhotoID756

Resistant outcrops of Proterozoic volcanic exhalites indicate that the Cleator, AZ, region was once part of a volcanic arc setting. These outcrops are comprised of dark chert; nearby outcrops are comprised of banded iron formation and also are reported to include tourmalinite, a chemical sedimentary rock comprised of precipitated tourmaline.
PhotoID756

Photograph: Ben Murphy

Reference: Slack et al., 2007, Suboxic deep seawater in the late Paleoproterozoic: Evidence from hematitic chert and iron formation related to seafloor-hydrothermal sulfide deposits, central Arizona, USA, Earth and Planetary Science Letters, 255, p. 243-256. Anderson, C.A., 1972, Precambrian Rocks in the Cordes Area, Yavapai County, Arizona, US Geological Survey Bulletin 1345. (Find it on ngmdb.usgs.gov)