Poway Formation

Poway Formation
Stratigraphic range: Paleogene
Type Formation
Location
Region San Diego County, California
Country United States

The Poway Formation is a geologic formation in San Diego County, Southern California. It preserves fossils dating back to the Paleogene period.[1]

Poway clasts

Volcanic clastic rock cobbles of rhyolite, in a sandstone matrix in this area are named Poway clasts.[2]

The ancient Ballena River brought rhyolite-gravel, or “Poway" clasts, from a region in present-day Sonora, Mexico to the Pacific Ocean. Its sediments deposited into alluvial fan-submarine canyon-submarine fan complex extending for miles offshore. Remnants of submarine fan facies outcrops are found as far west as the northern Channel Islands. Inland Ballena River deposits outcrop discontinuously over 16 miles (26 km) in a west-southwest trend from Whale Mountain to San Vicente Reservoir, here the river was up to 2 miles (3.2 km) in width through Peninsular Ranges.[3]

See also

References

  1. ↑ Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 31 July 2014. Retrieved 8 July 2014.
  2. ↑ San Diego Mesa College: Tecolote Canyon: A Geologic Overview Archived 2015-07-10 at the Wayback Machine. — with Poway Clasts image.
  3. ↑ Geiconsultants.com: "Geologic Formations of Western San Diego County", by Jeffrey D. Brown, R.G., C.E.G., GEI Consultants, Inc. − c.1996.


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