Nov 19, 2024 · The Picture Gorge Basalts (PGBs) are found all throughout the Sheep Rock Unit of the monument, seen close to the tops of the John Day Valley's peaks. These basalts were emplaced 16 million years ago (Mya) by a series of 61 sporadic lava flows that erupted, on average, every 15,000 year from fissures in the Earth’s crust.

The Columbia River Basalt Group (including the Steen and Picture Gorge basalts) extends over portions of four states. The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over 210,000 km 2 (81,000 sq mi) mainly eastern Oregon and Washington, western ...

Jan 31, 2020 · We explore the Picture Gorge Basalt (PGB) formation of the CRBG, and discuss the location and geochemical significance in a temporal context of early CRBG magmatism.

Feb 9, 2023 · The Picture Gorge Basalt (PGB) of the Columbia River Basalt Group (CRBG) has been previously thought to be limited in its eruptive volume (<3000 km 3) and thought to not extend far from its type locality.

The Picture Gorge Basalt (PGB) is part of the Miocene Columbia River Basalt Group (CRBG). The PGB, which outcrops in eastern Oregon, is considered coincident in time with the voluminous Grande Ronde Basalt. New radiometric ages have expanded the age‐range of the PGB, suggesting it began erupting prior to the Steens Basalt to its south and continued until after cessation of the Grande Ronde ...

Mar 23, 2025 · The Picture Gorge Basalt (PGB) is a small part of a large volcanic province in western North America that erupted 17–16 million years ago. The record of Earth's magnetic field frozen into these rocks has been used to correlate and map the sequences of lava flows throughout western North America.

The earliest-erupted basalts from this province aid in understanding and modeling plume impingement and the subsequent evolution of basaltic volcanism. We explore the Picture Gorge Basalt (PGB) formation of the CRBG, and discuss the location and geochemical significance in a temporal context of early CRBG magmatism.

PICTURE GORGE BASALT (Member of the CRB) Waters (1961) recognized two units of the Columbia River Basalts (CRB): Yakima, covering much of eastern Washington and Picture Gorge, restricted to central Oregon near a type locality of the same name on the John Day River 7 miles west of Dayville.

Feb 9, 2023 · This study focuses on extensive outcrops of basaltic lavas and dikes south of the type locality at Picture Gorge, in order to reassess the spatial distribution and eruptive volume of the PGB.

Jan 31, 2020 · We explore the Picture Gorge Basalt (PGB) formation of the CRBG, and discuss the location and geochemical significance in a temporal context of early CRBG magmatism.