Geology

Pahvant Butte

Millard County, UT

Coordinate verified

A ~15,500-year-old tuff cone that erupted under rising Lake Bonneville in the Black Rock Desert. Wave-cut beaches and the famous white “Lace Curtain” cliff expose palagonitized ash; UGS GeoSights highlights the underwater Surtseyan eruption story and fault-fed volcanism still active in the field (young basalt flows nearby).

Field facts

RegionMillard County, UT
Coordinates39.1313, -112.5516
AccessClear Lake Bird Refuge road east from SR-257 south of Delta, then signed spur toward the butte (UGS directions)
RockBasaltic tuff cone with Bonneville-level wave-cut shelf and palagonite
AgencyBLM public lands / adjacent Clear Lake refuge corridor
Also calledPavant Butte, Sugarloaf

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Public recreation data — BLM & Recreation.gov (RIDB). Verify current access, fees, and seasonal closures before traveling.

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