North Bay
North BayUSGS Topo Sheet: Belfair
Geographic coordinates: 47° 24.35' N, 122° 49.47' W
Paleoseismic record: Uplift
Setting: The site lies at the seaward edge of a small salt marsh that fringes the head of North Bay. The marsh marks the seaward edge of a nearly planar, heavily forested surface 100-200 m wide that, landward, lies at the foot of a sharp break in slope at an elevation of about 20 feet above mean sea level.
Stratigraphic description: About 85 cm of peat underlie the marsh fringing North Bay. The peat is in sharp contact with underlying slightly muddy fine- to medium-grained sand. Marine mollusc shells, many of them articulated, are abundant in the sand 70-80 cm below the base of the peat. Shells from this layer gave a radiocarbon age of about 3000 14C yr B.P.; organic sediment at the base of the peat gave a radiocarbon age of about 650 14C yr B.P.
Paleontology/paleoecology: Abundant wood, seeds of Prunus emarginata (bitter cherry), and rhizomes of Scirpus acutus (hard-stemmed bulrush) in the lower part of the peat that overlies the marine mollusc-bearing sediment indicate an abrupt lowering of relative sea level (uplift) associated with formation of the sand-peat contact. The section has been sampled for detailed analysis of seeds, diatoms, and other microfossils.
Geologic interpretation: : The stratigraphy resembles that at Lynch Cove on Hood Canal, 4 km to the north, where two or more meters of uplift about 1100 years ago has been documented (Bucknam and others, 1992). We infer that the North Bay site was uplifted during that same event.
Date of last work at site: May 1998
Status of work: Active
Published information on this site: None
Investigators: R. Bucknam, B. Sherrod
Please cite information on this page as:
Bucknam, R.C. and Sherrod, B.L., 1999, North Bay, in Bucknam, R.C., compiler, Atlas of reconnaissance data from paleoseismic studies of the Puget Sound region, Washington: U.S. Geological Survey Web site, http://earthquake.usgs.gov/regional/pacnw/paleo/atlas.php.
