Pleistocene megafloods in the northeast Pacific

Isotopically‐depleted late Pleistocene groundwater in Columbia River Basalt aquifers: Evidence for recharge of glacial Lake Missoula floodwaters?

“…The largest flood occurred post-19,015 + 165 14 C yr BP with peak discharges of at least 10 × 10 6 m 3 /s [Benito and O'Connor, 2003]. Low salinity anomalies determined from freshwater diatoms in marine sediments off the coast of southern Oregon reported glacial Lake Missoula flood events ranging between 14 to 16 k yrs BP, closely matching glacial Lake Missoula terrestrial flood dates as well as the age of the youngest Missoula flood associated turbidites in the Cascadia Basin [Lopes and Mix, 2009].…”

“…Six samples in the CRBAs display 14 C ages between ∼19-13 k yrs BP corresponding to the timing of at least 12 floods with discharges of >1.0 × 10 6 m 3 /s [Benito and O'Connor, 2003] (Figure 2b). Two of these six samples also correspond to Missoula flood event ages reported from 14 to 16 k yrs BP based on low salinity anomalies determined from freshwater diatoms in marine sediments off the coast of southern Oregon [Lopes and Mix, 2009] (Figure 2b). Twelve samples from the CRBAs demonstrate 14 C ages between 19 and 34 k yrs BP which correspond to pre late Pleistocene CIS-related flood events obtained from low salinity anomalies [Lopes and Mix, 2009], as well as radiocarbon age dates of Quaternary deposits in the Pasco Basin [Baker et al, 1991a].…”

“…Two of these six samples also correspond to Missoula flood event ages reported from 14 to 16 k yrs BP based on low salinity anomalies determined from freshwater diatoms in marine sediments off the coast of southern Oregon [Lopes and Mix, 2009] (Figure 2b). Twelve samples from the CRBAs demonstrate 14 C ages between 19 and 34 k yrs BP which correspond to pre late Pleistocene CIS-related flood events obtained from low salinity anomalies [Lopes and Mix, 2009], as well as radiocarbon age dates of Quaternary deposits in the Pasco Basin [Baker et al, 1991a]. The source of these flooding events prior to the onset of glacial Lake Missoula floods has been attributed to intermittent releases of subglacial meltwaters from the CIS and surge behavior during advances of the CIS [Shaw et al, 1999;Lopes and Mix, 2009].…”

Climate change decouples oceanic primary and export productivity and organic carbon burial

“…2C and SI Materials and Methods) in a manner similar to ref. 23, but excluding freshwater diatoms as these track river input (15) (Fig. 2D).…”

“…1). Under the coastal upwelling regime, the record from Ocean Drilling Program ( For cores ODP 1019 and MD02-2499, a radiocarbon-based age model (16,17) is further tuned by correlation of benthic δ 18 O to the radiocarbon-dated W8709-13PC (15,17). The chronology of core W8709-13PC is based on 40 planktonic foraminifera radiocarbon dates including data from ref.…”