Holocene environmental change and the accumulation–erosion balance of sheltered river-mouth sediments, Göteborg, SW Sweden

Seismic stratigraphy of Late Quaternary deposits in the eastern Skagerrak

“…In cores from the Go¨ta a¨lv estuary, several nonconformities have been documented, the longest from 10.0 to 4.0 ka BP (Nordberg and Bergsten, 1988;Nordberg, 1991;Klingberg, 1996;Brack et al, 2000). The estuary was earlier exposed to wave and current erosion, likely forming an nonconformity.…”

“…The estuary was earlier exposed to wave and current erosion, likely forming an nonconformity. With continuing isostatic uplift, these areas were sheltered by the uplifted islands and deposition could start again (Brack et al, 2000).…”

“…Major sediment sources in the area are Go¨ta a¨lv and Nordre a¨lv Rivers (Brack et al, 2000). Today the suspended sediments from the rivers are carried northwards from their outlets along the coast with currents, but earlier the river outlet was situated several kilometers upstream of the present eustuaries, first at Trollha¨ttan and later at Lilla Edet (Klingberg et al, 2006).…”

Sedimentological considerations for predictive modelling

“…Thus factors such as water depth, sediment supply, exposure to waves and bottom currents, salinity strati®cation and climate are variable even today. The uppermost 0.5±1 m of recent sediment represents the last 100 years when accumulation has dominated (Brack et al 2000). However, this period was preceded by nearly 1,000 years of erosion, thus caution needs to be exercised in concluding that these sediments might now be stable.…”