scholarly journals Testing the mid-Holocene relative sea-level highstand hypothesis in North Wales, UK

The Holocene ◽  
2019 ◽  
Vol 29 (9) ◽  
pp. 1491-1502
Author(s):  
Greg T Rushby ◽  
Geoff T Richards ◽  
W Roland Gehrels ◽  
William P Anderson ◽  
Mark D Bateman ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
Isostatic Adjustment ◽  
North Wales ◽  
Level Data ◽  
Northwest Europe ◽  
Holocene Sea Level

Accurate Holocene relative sea-level curves are vital for modelling future sea-level changes, particularly in regions where relative sea-level changes are dominated by isostatically induced vertical land movements. In North Wales, various glacial isostatic adjustment (GIA) models predict a mid-Holocene relative sea-level highstand between 4 and 6 ka, which is unsubstantiated by any geological sea-level data but affects the ability of geophysical models to model accurately past and future sea levels. Here, we use a newly developed foraminifera-based sea-level transfer function to produce a 3300-year-long late-Holocene relative sea-level reconstruction from a salt marsh in the Malltraeth estuary on the south Anglesey coast in North Wales. This is the longest continuous late-Holocene relative sea-level reconstruction in Northwest Europe. We combine this record with two new late-Holocene sea-level index points (SLIPs) obtained from a freshwater marsh at Rhoscolyn, Anglesey, and with previously published regional SLIPs, to produce a relative sea-level record for North Wales that spans from ca. 13,000 BP to the present. This record leaves no room for a mid-Holocene relative sea-level highstand in the region. We conclude that GIA models that include a mid-Holocene sea-level highstand for North Wales need revision before they are used in the modelling of past and future relative sea-level changes around the British Isles.

Late Holocene sea-level changes and isostasy in western Denmark

2006 ◽  
Vol 66 (2) ◽  
pp. 288-302 ◽  
Author(s):  
W. Roland Gehrels ◽  
Katie Szkornik ◽  
Jesper Bartholdy ◽  
Jason R. Kirby ◽  
Sarah L. Bradley ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Sea Level ◽  
Salt Marshes ◽  
Late Holocene ◽  
Glacial Isostatic Adjustment ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Tidal Embayment ◽  
Made In

AbstractCores and exposed cliff sections in salt marshes around Ho Bugt, a tidal embayment in the northernmost part of the Danish Wadden Sea, were subjected to 14C dating and litho- and biostratigraphical analyses to reconstruct paleoenvironmental changes and to establish a late Holocene relative sea-level history. Four stages in the late Holocene development of Ho Bugt can be identified: (1) groundwater-table rise and growth of basal peat (from at least 2300 BC to AD 0); (2) salt-marsh formation (0 to AD 250); (3) a freshening phase (AD 250 to AD 1600?), culminating in the drying out of the marshes and producing a distinct black horizon followed by an aeolian phase with sand deposition; and (4) renewed salt-marsh deposition (AD 1600? to present). From 16 calibrated AMS radiocarbon ages on fossil plant fragments and 4 calibrated conventional radiocarbon ages on peat, we reconstructed a local relative sea-level history that shows a steady sea-level rise of 4 m since 4000 cal yr BP. Contrary to suggestions made in the literature, the relative sea-level record of Ho Bugt does not contain a late Holocene highstand. Relative sea-level changes at Ho Bugt are controlled by glacio-isostatic subsidence and can be duplicated by a glacial isostatic adjustment model in which no water is added to the world's oceans after ca. 5000 cal yr BP.

scholarly journals Relative sea-level changes and glacio-isostatic adjustment on the Magdalen Islands archipelago (Atlantic Canada) from MIS 5 to the late Holocene

2017 ◽  
Vol 171 ◽  
pp. 216-233 ◽  
Author(s):  
Audrey M. Rémillard ◽  
Guillaume St-Onge ◽  
Pascal Bernatchez ◽  
Bernard Hétu ◽  
Jan-Pieter Buylaert ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Atlantic Canada ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Mis 5 ◽  
Magdalen Islands

scholarly journals Late Holocene (0–6 ka) sea-level changes in the Makassar Strait, Indonesia

2020 ◽  
Vol 16 (4) ◽  
pp. 1187-1205 ◽  
Author(s):  
Maren Bender ◽  
Thomas Mann ◽  
Paolo Stocchi ◽  
Dominik Kneer ◽  
Tilo Schöne ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Glacial Isostatic Adjustment ◽  
Mantle Structure ◽  
Ice Melting ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
The Past ◽  
Isostatic Adjustment ◽  
Spermonde Archipelago

Abstract. The Spermonde Archipelago, off the coast of southwest Sulawesi, consists of more than 100 small islands and hundreds of shallow-water reef areas. Most of the islands are bordered by coral reefs that grew in the past in response to paleo relative sea-level changes. Remnants of these reefs are preserved today in the form of fossil microatolls. In this study, we report the elevation, age, and paleo relative sea-level estimates derived from fossil microatolls surveyed in five islands of the Spermonde Archipelago. We describe 24 new sea-level index points, and we compare our dataset with both previously published proxies and with relative sea-level predictions from a set of 54 glacial isostatic adjustment (GIA) models, using different assumptions on both ice melting histories and mantle structure and viscosity. We use our new data and models to discuss Late Holocene (0–6 ka) relative sea-level changes in our study area and their implications in terms of modern relative sea-level estimates in the broader South and Southeast Asia region.

scholarly journals New insights on the relative sea level changes during the Late Holocene along the coast of Paros Island and the northern Cyclades (Greece)

2020 ◽  
Vol 63 (6) ◽  
Author(s):  
Eleni Kolaiti ◽  
Nikos Mourtzas
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Recent Change ◽  
Hellenistic Period ◽  
Neolithic Period ◽  
Sea Level Changes ◽  
Late Neolithic ◽  
Relative Sea Level ◽  
Sea Levels ◽  
History Of

Geomorphological and archaeological indicators of former sea levels along the coast of Paros enabled us to determine and date six distinct sea level stands and the relative sea level (rsl) changes between them, as well as plot the rsl curve for the last 6,300 years. The Late Holocene history of the rsl change in Paros began with the sea level at 4.90 ± 0.10 m below mean sea level (bmsl) dated to the Late Neolithic period (4300 BC-3700 BC). The next sea level at 3.50 ± 0.20 m bmsl is dated to the Geometric and Archaic period of the Cyclades (1050 BC-490 BC) and most probably lasted during the Hellenistic period (323-146 BC). The sea level at 2.40 ± 0.25 m bmsl is dated to the Roman period (146-400 AD) and the next sea level at 1.35 ± 0.20 m bmsl to the Venetian period of the Cyclades (1207-1537). The sea level at 0.80 ± 0.10 m bmsl is dated to after the Venetian period, during the Ottoman rule of the island (1537-1821). The youngest sea level stand at 0.45 ± 0.10 m is attributed to the recent change in the sea level after the late 19th c. onward. The separation between glacio-hydro-isostatic signals and the observed rsl change on Paros Island, in an area of seismic quiescence, demonstrates a significant tectonic component in the rsl changes. Moreover, the sea level stands deduced from Paros in comparison with those from the northern Cyclades indicate a uniform tectonic behaviour of the entire northern and central section of the Cyclades plateau.

scholarly journals Radiocarbon Ages of Beach Rocks and Late Holocene Sea-Level Changes in the Southern Part of the Nansei Islands, Southwest of Japan

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 887-898 ◽  
Author(s):  
Kunio Omoto
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Ishigaki Island ◽  
The Past ◽  
Nansei Islands ◽  
Beach Rock ◽  
Holocene Sea Level

Beach rock is a good indicator of the past sea levels, as it is considered to have been formed within the range of intertidal zone. Radiocarbon dates of beach rocks collected from Iriomote Island, Ishigaki Island, and Miyako Island, in the southern part of the Nansei Islands, indicate that the beach rocks were formed between around 4000 BP and 400 BP. Late Holocene sea-level changes were revealed based on the elevations and 14C dates of the beach rocks. The results indicate that the sea level was similar to the present one for at least the past 4000 BP. Isotopic fractionations (δ13C) of the beach rocks were between +9.40% and −0.08%, suggesting a different origin for calcium carbonate.

scholarly journals Late Holocene sea-level changes and vertical land movements in New Zealand

2020 ◽  
pp. 1-16
Author(s):  
Daniel J. King ◽  
Rewi M. Newnham ◽  
W. Roland Gehrels ◽  
Kate J. Clark
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Late Holocene ◽  
Sea Level Changes ◽  
Holocene Sea Level

Causes and implications of Mid- to Late Holocene relative sea-level change in the Gulf of Kachchh, western India

2020 ◽  
pp. 1-24
Author(s):  
Shubhra Sharma ◽  
Gaurav Chauhan ◽  
Anil Dutt Shukla ◽  
Romi Nambiar ◽  
Ravi Bhushan ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
River Estuary ◽  
Western India ◽  
Tidal Amplitude ◽  
Relative Sea Level ◽  
Gulf Of Kachchh ◽  
Level Change ◽  
Isostatic Adjustment ◽  
Positive Tendency

Abstract The relict intertidal deposits from the Kharod River Estuary, Gulf of Kachchh, and the distal end of Kori Creek are used to infer the Mid- to Late Holocene relative sea-level (RSL) change in western India. Employing sedimentology, geochemistry, palynology, ichnology, and optical and radiocarbon dating, the study suggests the dominance of fluvial activity between 16.5 ± 1.6 and 9.9 ± 0.7 ka. After ~7 ka (7.3 ± 0.4, 6.8 ± 0.5 ka), the sea level showed a positive tendency until 4.7 ± 0.2 ka. The tectonically corrected Mid-Holocene RSL change is estimated as 1.45 ± 0.33 m between ~7 and ~5 ka. The study suggests that the Mid-Holocene RSL high was due to the meltwater contribution from the Himalayan cryosphere, with subordinate contribution from glacio-isostatic adjustment and crustal subsidence. The Late Holocene tectonically corrected RSL change at ~1 ka (1.1 ± 0.1 ka and 1045 ± 175 cal yr BP) is estimated as 0.53 ± 0.43 m. This is ascribed to monsoon wind-driven tidal ingression that might have affected the tidal amplitude positively. The study suggests that the Mid-Holocene RSL change did not play a deterministic role in the abandonment of the Harappan coastal settlements.

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