The Portland Basin: A Big River Runs Through It Reports Example
Metropolitan Portland in Oregon has a unique setting as it lies within a small basin in the forearc of the Cascadia subduction system. A small Neogene to Holocene basin owes its existence to its convergent-margin tectonic setting primarily. Such a unique setting makes the basin preserve “a complex record of aggradation and incision in response to distant as well as local tectonic, volcanic, and climatic events” (Evarts, O’Connor, Wells, and Madin, 2009, p. 4). Lots of different natural disasters led to significant tectonic deformation of the region. The decades of research of the peculiarities of the basin demonstrated that this is a globally unique setting that definitely requires further study and observations. Cataclysmic floods and volcanic debris have a major impact on the surface formation.
The Portland Basin represents one of the topographic and structural depressions that constitute the Puget-Willamette forearc. The uniqueness of the setting derives from the fact that it is bisected by the lowest levels of the Columbia River that cuts through the active volcanic arc. Therefore, the Portland Basin is famous not only for its local tectonic and volcanic events, but also for some geologic events of national scale. The river has great impact on the formation of inundations and flaws. Careful research in geology, meteorology and geophysics is needed for projection and monitoring of natural events in the region. Experts agree that “The events at the Cascade Rapids had direct and substantial effects on the ecology and human use of the lower Columbia” (O’Connor, 2004, p. 403).
Exceptional location of the Portland Basin bisected by one of the largest continental rivers in the world has put it into a predisposition to local and regional tectonic and geologic processes. The special geologic situation of the Columbia River Gorge is predominantly the result of geologic cataclysms in the region (O’Connor, 2004, p. 416). The convergent margin also plays a significant role in the structural formation of the basin. Moreover, the region is highly subjected to the effects of distant volcanic and environmental events. The climate change has also influenced basin sedimentation and erosion that continue to have its impact on the surface formation and landforms of the Portland Basin.
Evarts, Russell C., O’Connor, Jim E., Wells, Ray E., and Madin, Ian P. “The Portland Basin: A (big) River Runs through It.” GSA Today 19.9 (2009): 4-10.
O’Connor, Jim E. The Evolving Landscape of the Columbia River Gorge. Oregon Historical Quarterly 105.3 (2004): 390-421.