Sandy barrier overstepping and preservation linked to rapid sea level rise and geological setting

Andrew Cooper, Andrew Green, Ricardo Meireles, Antonio Klein, Jorge Souza, Elirio Toldo

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

In an era of global rising sea level, quantifying future shoreline behaviour is a key societal concern. The potential for dramatic shoreline change via overstepping or barrier disintegration on barrier-lagoon coasts as a result of future rapid sea level rise has been considered by various authors, but documented examples of barrier overstepping generally involve either coarse grain sizes or early diagenesis as beachrock. Where overstepping has been inferred, the overstepped barrier is seldom preserved. Using high resolution seismic data we describe the mid-Holocene overstepping of a sandy coastal barrier system and subsequent geomorphological changes that ultimately transformed it into a strandplain fronted by a muddy shoreface. This complete change in character is interpreted in the context of rapid sea level rise (tentatively linked to the 8.2 ka event) during which the former sandy shoreface-barrier was overstepped and decoupled from the contemporary shoreline, leaving the latter sand-starved. Upon overstepping, the wave-influenced shoreline was displaced rapidly to the landward margin of the former lagoon. Preservation of the overstepped uncohesive sandy barrier is attributed to the relatively wave-sheltered location, rapid sea level rise and rapid burial by shoreface sediments. This situation provides an insight into the conditions under which overstepping occurs, and thereby, the future response of barrier-lagoon systems to predicted rapid rates of future sea level rise.
LanguageEnglish
Pages80-91
JournalMarine Geology
Volume382
Early online date15 Oct 2016
DOIs
Publication statusPublished - 17 Feb 2017

Fingerprint

Sea level
shoreline
lagoon
beachrock
shoreline change
Disintegration
diagenesis
seismic data
grain size
Holocene
Coastal zones
Sediments
Sand
sand
sea level rise
coast
sediment

Keywords

  • Sea level rise
  • meltwater pulse
  • overstepping
  • barrier
  • nearshore stratigraphy
  • seismic stratigraphy
  • Holocene

Cite this

Cooper, Andrew ; Green, Andrew ; Meireles, Ricardo ; Klein, Antonio ; Souza, Jorge ; Toldo, Elirio. / Sandy barrier overstepping and preservation linked to rapid sea level rise and geological setting. In: Marine Geology. 2017 ; Vol. 382. pp. 80-91.
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Sandy barrier overstepping and preservation linked to rapid sea level rise and geological setting. / Cooper, Andrew; Green, Andrew; Meireles, Ricardo; Klein, Antonio; Souza, Jorge; Toldo, Elirio.

In: Marine Geology, Vol. 382, 17.02.2017, p. 80-91.

Research output: Contribution to journalArticle

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