TY - JOUR
T1 - Stratigraphy, evolution, and controls of a Holocene transgressive-regressive barrier island under changing sea-level
T2 - Danish North Sea coast
AU - Fruergaard, Mikkel
AU - Møller, Ingelise
AU - Johannessen, Peter
AU - Nielsen, Lars Henrik
AU - Andersen, Thorbjørn Joest
AU - Nielsen, Lars
AU - Sander, Lasse
AU - Pejrup, Morten
PY - 2015/7/1
Y1 - 2015/7/1
N2 - This study provides a detailed reconstruction of the formation of a wave-dominated barrier island and assesses the sedimentological and morphological effects of sea-level changes on barrier evolution. Sedimentological and stratigraphic characteristics of the Holocene deposits are resolved by percussion cores and an extensive ground-penetrating-radar survey. A high-resolution chronology of the cored barrier island deposits is constructed by optically stimulated luminescence dating. This approach facilitates a high spatio-temporal resolution of the island’s morphological and depositional evolution. The results show that the barrier island experienced multiple phases of transgressions and regressions during the mid- and late Holocene and that these changes were driven primarily by changes in rates of sea-level rise, sediment supply and the impact of storms. Due to the postglacial sea-level rise, the seaward part of the study area was transgressed by the retreating mainland shoreline, forming a back-barrier basin. At the time of the initial transgression, sea level was rising by more than 4.0 mm yr−1. As sea-level rise decreased to less than 2 mm yr−1 the back-barrier basin rapidly started to fill with sediments before being transgressed by the still retreating open-ocean shoreline. These events were associated with periods of very rapid landward displacement of up to 10 m yr−1 of the mainland shoreline. After stabilization of the barrier island in its most eastward (i.e., landward) location, the open-ocean shoreline prograded about 3 km seaward at a rate of > 3 m yr−1 through the deposition of a 7-m-thick sandy beach and shoreface succession. The progradation occurred despite a sea-level rise of about 1.8 mm yr−1. After the regressive period the barrier island once again became transgressive before shifting back to its current regressive stage. The study shows how comparable rates of sea-level rise can result in very different morphological responses for a single barrier island since sediment supply apparently has varied significantly through time. It also appears that a transgressive situation is reached for this particular barrier island for a sea-level rise higher than about 2 mm yr−1. This gives reason for concern since a number of sea-level change scenarios indicate that such a rate will be reached within a few decades.
AB - This study provides a detailed reconstruction of the formation of a wave-dominated barrier island and assesses the sedimentological and morphological effects of sea-level changes on barrier evolution. Sedimentological and stratigraphic characteristics of the Holocene deposits are resolved by percussion cores and an extensive ground-penetrating-radar survey. A high-resolution chronology of the cored barrier island deposits is constructed by optically stimulated luminescence dating. This approach facilitates a high spatio-temporal resolution of the island’s morphological and depositional evolution. The results show that the barrier island experienced multiple phases of transgressions and regressions during the mid- and late Holocene and that these changes were driven primarily by changes in rates of sea-level rise, sediment supply and the impact of storms. Due to the postglacial sea-level rise, the seaward part of the study area was transgressed by the retreating mainland shoreline, forming a back-barrier basin. At the time of the initial transgression, sea level was rising by more than 4.0 mm yr−1. As sea-level rise decreased to less than 2 mm yr−1 the back-barrier basin rapidly started to fill with sediments before being transgressed by the still retreating open-ocean shoreline. These events were associated with periods of very rapid landward displacement of up to 10 m yr−1 of the mainland shoreline. After stabilization of the barrier island in its most eastward (i.e., landward) location, the open-ocean shoreline prograded about 3 km seaward at a rate of > 3 m yr−1 through the deposition of a 7-m-thick sandy beach and shoreface succession. The progradation occurred despite a sea-level rise of about 1.8 mm yr−1. After the regressive period the barrier island once again became transgressive before shifting back to its current regressive stage. The study shows how comparable rates of sea-level rise can result in very different morphological responses for a single barrier island since sediment supply apparently has varied significantly through time. It also appears that a transgressive situation is reached for this particular barrier island for a sea-level rise higher than about 2 mm yr−1. This gives reason for concern since a number of sea-level change scenarios indicate that such a rate will be reached within a few decades.
U2 - 10.2110/jsr.2015.53
DO - 10.2110/jsr.2015.53
M3 - Journal article
SN - 1527-1404
VL - 85
SP - 820
EP - 844
JO - Journal of Sedimentary Research
JF - Journal of Sedimentary Research
IS - 7
ER -