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.

Late Holocene Sea-Level Change on Rota and Guam, Mariana Islands, and Its Constraint on Geophysical Predictions

1993 ◽  
Vol 40 (2) ◽  
pp. 189-200 ◽  
Author(s):  
Hajime Kayanne ◽  
Teruaki Ishii ◽  
Eiji Matsumoto ◽  
Nobuyuki Yonekura
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Sea Level Change ◽  
Mariana Islands ◽  
Present Level ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
Level Change ◽  
Sea Level Variations ◽  
Holocene Sea Level

AbstractHolocene emergent reefs and notches are well distributed on Rota and Guam. Relative sea-level changes at these islands are reconstructed based on geomorphological observations and borings on present and emergent reefs, together with 54 radiocarbon dates. Sea level rose gradually to a maximum of 1.8 m between 6000 and 4200 yr B.P. and reached its highest level by 4200 yr B.P. on both islands. After 3200 yr B.P. abrupt uplift caused emergence of the reef. By subtracting the tectonic effect, we obtained the sea-level change in the Marianas: sea level reached its present level by 4200 yr B.P. and has remained almost stable since then. Reconstructed late Holocene sea-level change in the Mariana Islands provides constraints on geophysical models of sea-level variations.

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 diatom biostratigraphy and sea-level changes in the southeastern Beaufort Sea

2000 ◽  
Vol 37 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Stéphane Campeau ◽  
Arnaud Héquette ◽  
Reinhard Pienitz
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Beaufort Sea ◽  
Sea Level Changes ◽  
Diatom Assemblages ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Temporal Precision ◽  
Level Change ◽  
Paleoenvironmental Changes

Late Holocene sediments from the Atkinson Point area were analysed to provide quantitative reconstructions of recent sea-level changes in the southeastern Beaufort Sea. The succession of diatom assemblages in five cores revealed paleoenvironmental changes induced by the transgression of the Beaufort Sea during successive periods of lacustrine conditions, breaching and flooding of thermokarst lakes by the sea, and the landward migration of sandy spits. Based on radiocarbon dates and quantitative paleodepth determinations, a relative sea-level curve for the late Holocene has been developed. Despite a loss of temporal precision due to old carbon contamination, an envelope of sea-level change has been defined for the last 2 ka BP, suggesting a sea-level rise in the order of 1.1 mm a-1 for the last millennium. This paper presents the first sea-level reconstruction inferred from a diatom-based transfer function. It represents an improvement over traditional methods which were limited to qualitative estimates of past sea levels.

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

Late Holocene sea-level changes along the southern coast of Finland, Baltic Sea

2007 ◽  
Vol 242 (1-3) ◽  
pp. 27-38 ◽  
Author(s):  
Arto Miettinen ◽  
Henrik Jansson ◽  
Teija Alenius ◽  
Georg Haggrén
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Late Holocene ◽  
Southern Coast ◽  
Sea Level Changes ◽  
Holocene Sea Level

scholarly journals Relative sea-level changes in crete: reassessment of radiocarbon dates from Sphakia and west Crete

2002 ◽  
Vol 97 ◽  
pp. 171-200 ◽  
Author(s):  
Simon Price ◽  
Tom Higham ◽  
Lucia Nixon ◽  
Jennifer Moody
Keyword(s):  
Sea Level ◽  
Late Antiquity ◽  
Isotopic Fractionation ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Catastrophic Earthquake ◽  
Radiocarbon Data ◽  
Calendar Dates

This article is concerned with the recognition and dating of Holocene relative sea-level changes along the coast of west Crete (an island located in the active Hellenic subduction arc of the southern Aegean) and in particular in Sphakia. Radiocarbon data for changes in sea levels collected and analysed previously must (a) be recorrected to take into account isotopic fractionation, and (b) recalibrated by using the new marine reservoir value. These new radiocarbon dates are analysed using Bayesian statistics. The resulting calendar dates for changes in sea level are younger than previously assumed. In particular the Great Uplift in western Crete in late antiquity must be dated to the fifth or sixth century AD, not to AD 365. Moreover, recent work on tectonics suggests that the Great Uplift need not have been accompanied by a catastrophic earthquake. Finally, we consider the consequences of the Great Uplift for some coastal sites in Sphakia.

The Norse in Greenland and late Holocene sea-level change

Polar Record ◽  
2008 ◽  
Vol 44 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Naja Mikkelsen ◽  
Antoon Kuijpers ◽  
Jette Arneborg
Keyword(s):  
Sea Level ◽  
Little Ice Age ◽  
Late Holocene ◽  
Ice Age ◽  
Documentary Evidence ◽  
Sea Level Changes ◽  
Middle Holocene ◽  
Level Change ◽  
Farming Community ◽  
Holocene Sea Level

ABSTRACTNorse immigrants from Europe settled in southern Greenland in around AD 985 and managed to create a farming community during the Medieval Warm Period. The Norse vanished after approximately 500 years of existence in Greenland leaving no documentary evidence concerning why their culture foundered. The flooding of fertile grassland caused by late Holocene sea-level changes may be one of the factors that affected the Norse community. Holocene sea-level changes in Greenland are closely connected with the isostatic response of the Earth's crust to the behaviour of the Greenlandic ice sheet. An early Holocene regressive phase in south and west Greenland was reversed during the middle Holocene, and evidence is found for transgression and drowning of early-middle Holocene coast lines. This drowning started between 8 and 7ka BP in southern Greenland and continued during the Norse era to the present. An average late Holocene sea level rise in the order of 2–3 m/1000 years may be one of the factors that negatively affected the life of the Norse Greenlanders, and combined with other both socio-economic and environmental problems, such as increasing wind and sea ice expansion at the transition to the Little Ice Age, may eventually have led to the end of the Norse culture in Greenland.

Influence of the "Hypsithermal Age" and "Neoglaciation" climatic conditions on the Brazilian coast.

2001 ◽  
Vol 28 (2) ◽  
pp. 213 ◽  
Author(s):  
KENITIRO SUGUIO
Keyword(s):  
United States ◽  
Gulf Of Mexico ◽  
Sea Level ◽  
Southeastern United States ◽  
Climatic Conditions ◽  
Brazilian Coast ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
The Past

Meanwhile the highest relative sea-level is the present one in southeastern United States (Gulf of Mexico) or in Netherlands coast, most of the Brazilian coast exhibited Holocene sea-levels higher than the present in the past. The Brazilian curves, representing the relative sea-level changes during last 7.000 years, are outlined using sedimentological, biological and prehistorical past sea-level records. This paper shows that these relative sea-level records, during the Holocene, can be suitably used to demonstrate the influence of the worldwide known paleoclimatic events, like the “Hypsithermal Age” and “Neoglaciation” on the Brazilian coast.

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