Portland Basin (geology)

The Portland Basin is a roughly 770-square-mile (2,000 km2) topographic and structural depression in the central Puget-Willamette Lowland.[1] The Portland Basin is approximately 40 miles (64 km) long and 20 miles (32 km) wide, with its long axis oriented northwest.[2] Studies indicate that as much as 1,800 feet (550 m) of late Miocene and younger sediments have accumulated in the deepest part of the basin near Vancouver. Most of the basin-fill material was carried in from the east by the Columbia River.[3]

References

  1. ↑ Beeson, M.H., Tolan, T.L., and Anderson, J.L., 1989, The Columbia River Basalt Group in Western Oregon; Geologic Structures and other Factors that Controlled Flow Emplacement Patterns, in Reidel, S.P. and Hooper, P.R., eds., Volcanism and tectonism in the Columbia River flood-basalt province, Geologic Society of America Special Paper 239, p223-246
  2. ↑ Evarts, Russell C., 2004, Geologic Map of the Ridgefield Quadrangle, Clark and Cowlitz Counties, Washington, U.S. Geological Survey
  3. ↑ Liberty, L.M., Hemphill-Haley, M.A., and Madin, I.P., 2003, The Portland Hills Fault –uncovering a hidden fault in Portland, Oregon using high-resolution geophysical methods, Tectonphysics, v.368. p. 89-103
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