scholarly journals Last interglacial sea-level history from speleothems: a global standardized database

2021 ◽  
Vol 13 (5) ◽  
pp. 2077-2094
Author(s):  
Oana A. Dumitru ◽  
Victor J. Polyak ◽  
Yemane Asmerom ◽  
Bogdan P. Onac
Keyword(s):  
Sea Level ◽  
Current Knowledge ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Sea Levels ◽  
Isostatic Adjustment ◽  
Spatial Coverage ◽  
Uplift Rates ◽  
Regional Tectonic ◽  
Mis 5

Abstract. Speleothems (secondary cave carbonate precipitates) are archives of valuable information for reconstructing past sea levels as they are generally protected from weathering and erosion by their location and can be dated with U-series methods. Two main categories of speleothems are recognized as sea-level indicators: phreatic overgrowth on speleothems (POSs) and submerged vadose speleothems (SVSs). POSs have the great advantage that they precipitate on preexisting supports (vadose speleothems or cave walls) at a brackish water level equivalent to sea level when air-filled chambers of coastal caves are flooded by rising sea. SVSs are also useful, but sea level is inferred indirectly as periods of growth provide constraints on maximum sea-level positions, whereas growth hiatuses, sometimes difficult to observe, may indicate times when cave passages are submerged by sea highstands; hence they record minimum sea-level elevations. Here we describe a compilation that summarizes the current knowledge of the complete last interglacial (in its broadest sense from ∼ 140 to 70 ka, also known as marine isotope stage (MIS) 5) sea level captured by speleothems. We used the framework of the World Atlas of Last Interglacial Shorelines (WALIS), a comprehensive sea-level database, to provide a standardized format in order to facilitate scientific research on MIS 5 sea level. The discussion is focused on MIS 5e, but records that capture MIS 5d, 5c, 5b, and 5a are also included. We present the data from 71 speleothems (36 sea-level index points and 37 limiting points) in coastal caves located in 10 different locations, and we include the spatial coverage, the samples used, and their accuracy as indicators of sea level, U and Th isotopes used to generate the chronologies, and their scientific relevance to understand past sea-level changes. Furthermore, the paper emphasizes the usefulness of these indicators not only to render information regarding the eustatic sea level, but also for their contribution to refine the glacial isostatic adjustment models and to constrain regional tectonic uplift rates. The standardized sea-level database presented here is the first of its kind derived from speleothems and contains all the information needed to assess paleo relative sea levels and the chronological constraints associated with them. The database is available open-access at https://doi.org/10.5281/zenodo.4313860 (Dumitru et al., 2020). We refer the readers to the official documentation of the WALIS database at https://walis-help.readthedocs.io/en/latest/ (last access: 20 January 2021), where the meaning of each field is explained in detail.

scholarly journals Last Interglacial (<i>sensu lato</i>, ~130 to 75 ka) sea level history from cave deposits: a global standardized database

2020 ◽  
Author(s):  
Oana A. Dumitru ◽  
Victor J. Polyak ◽  
Yemane Asmerom ◽  
Bogdan P. Onac
Keyword(s):  
Sea Level ◽  
Current Knowledge ◽  
Active Regions ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Sea Levels ◽  
Cave Deposits ◽  
Spatial Coverage ◽  
Regional Tectonic ◽  
Mis 5

Abstract. Cave deposits are powerful archives for reconstructing past sea levels as they are generally protected from weathering and erosion by their location and can be dated with U-series methods. Two main categories of cave deposits are recognized as sea level indicators: phreatic overgrowth on speleothems (POS) and submerged vadose speleothems (SVS). POS have the great advantage that they precipitate on preexisting vadose supports at a brackish water level equivalent to sea level when air-filled chambers of coastal caves are flooded by rising sea. SVS are also useful, but sea level is inferred indirectly as periods of growth provide constraints on maximum sea level positions, whereas growth hiatuses, sometimes difficult to observe, may indicate times when cave passages are submerged by sea high stands, hence they record minimum sea level elevations. Here we describe a compilation that summarizes the current knowledge of MIS 5 (sensu lato) sea level captured by cave deposits. We used the framework of the World Atlas of Last Interglacial Shorelines (WALIS), a comprehensive sea level database, to provide a standardized format in order to facilitate scientific research on MIS 5 sea level. The discussion is MIS 5e-centered, but records that capture MIS 5c and 5a are also included. We present the data from 59 cave deposits (26 sea-level index points and 33 limiting points) in coastal caves located in eight different locations, and we include the spatial coverage, the samples used and their accuracy as indicators of sea level, the isotopic characteristics used to generate the U-Th chronologies, and their scientific relevance to understand past sea-level changes. The paper also emphasizes how some of these indicators are useful not only for the information they offer about the eustatic sea level, but more importantly: i) those from tectonically stable areas provide information on Earth deformation and regional ice sheet histories, thus refining the glacial isostatic adjustments models and ii) those from active regions can constrain regional tectonic uplift rates. The standardized sea-level database presented here is the first of its kind derived from cave deposits and contains all the information needed to assess former paleo relative sea level and the chronological constraints associated with them. The database is available open-access at http://doi.org/10.5281/zenodo.4313861 (Dumitru et al., 2020).

scholarly journals Towards assessing the influence of sediment loading on Last Interglacial sea level

2019 ◽  
Vol 220 (1) ◽  
pp. 384-392
Author(s):  
T Pico
Keyword(s):  
Sea Level ◽  
Tectonic Uplift ◽  
Sediment Loading ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Isostatic Adjustment ◽  
Uplift Rates ◽  
History Of ◽  
The Impact ◽  
The Last Glacial

SUMMARY Locally, the elevation of last interglacial (LIG; ∼122 ka) sea level markers is modulated by processes of vertical displacement, such as tectonic uplift or glacial isostatic adjustment, and these processes must be accounted for in deriving estimates of global ice volumes from geological sea level records. The impact of sediment loading on LIG sea level markers is generally not accounted for in these corrections, as it is assumed that the impact is negligible except in extremely high depositional settings, such as the world's largest river deltas. Here we perform a generalized test to assess the extent to which sediment loading may impact global variability in the present-day elevation of LIG sea level markers. We numerically simulate river sediment deposition using a diffusive model that incorporates a migrating shoreline to construct a global history of sedimentation over the last glacial cycle. We then calculate sea level changes due to this sediment loading using a gravitationally self-consistent model of glacial isostatic adjustment, and compare these predictions to a global compilation of LIG sea level data. We perform a statistical analysis, which accounts for spatial autocorrelation, across a global compilation of 1287 LIG sea level markers. Though limited by uncertainties in the LIG sea level database and the precise history of river deposition, this analysis suggests there is not a statistically significant global signal of sediment loading in LIG sea level markers. Nevertheless, at sites where LIG sea level markers have been measured, local sea level predicted using our simulated sediment loading history is perturbed up to 16 m. More generally, these predictions establish the relative sensitivity of different regions to sediment loading. Finally, we consider the implications of our results for estimates of tectonic uplift rates derived from LIG marine terraces; we predict that sediment loading causes 5–10 m of subsidence over the last glacial cycle at specific locations along active margin regions such as California and Barbados, where deriving long-term tectonic uplift rates from LIG shorelines is a common practice.

Venice lagoon salt marsh vulnerability and halophytic vegetation vertical migration in response to sea level rise

2020 ◽  
Author(s):  
Zhicheng Yang ◽  
Sonia Silvestri ◽  
Marco Marani ◽  
Andrea D’Alpaos
Keyword(s):  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
Salt Marshes ◽  
Current Knowledge ◽  
Venice Lagoon ◽  
Sea Level Changes ◽  
Human Pressure ◽  
Sea Levels ◽  
Vegetation Species

&lt;p&gt;Salt marshes are biogeomorphic systems that provide important ecosystem services such as carbon sequestration and prevention of coastal erosion. These ecosystems are, however, threatened by increasing sea levels and human pressure. Improving current knowledge of salt-marsh response to changes in the environmental forcing is a key step to understand and predict salt-marsh evolution, especially under accelerated sea level rise scenarios and increasing human pressure. Towards this goal, we have analyzed field observations of marsh topographic changes and halophytic vegetation distribution with elevation collected over 20 years (between 2000 and 2019) in a representative marsh in the Venice lagoon (Italy).&lt;/p&gt;&lt;p&gt;Our results suggest that: 1) on average, marsh elevation with respect to local mean sea level decreased , (i.e. the surface accretion rate was lower than the rate of sea level rise); 2) elevational frequency distributions are characteristic for different halophytic vegetation species, highlighting different ecological realized niches that change in time; 3) although the preferential elevations at which different species have changed in time, the sequence of vegetation species with increasing soil elevation was preserved and simply shifted upward; 4) we observed different vegetation migration rates for the different species, suggesting that the migration process is species-specific. In particular, vegetation species colonizing marsh edges (Juncus and Inula) migrated faster facing to changes in sea levels than Limonium and Spartina , while Sarcocornia was characterized by delayed migration in response to sea level changes. These results bear significant implications for long-term biogeomorphic evolution of tidal environments.&lt;/p&gt;

scholarly journals The last interglacial sea-level record of Aotearoa New Zealand

2021 ◽  
Vol 13 (7) ◽  
pp. 3399-3437
Author(s):  
Deirdre D. Ryan ◽  
Alastair J. H. Clement ◽  
Nathan R. Jankowski ◽  
Paolo Stocchi
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Active Tectonics ◽  
Last Interglacial ◽  
Isostatic Adjustment ◽  
The North ◽  
Aotearoa New Zealand ◽  
Modern Analogue ◽  
Marine Isotope Stage 5 ◽  
Mis 5

Abstract. This paper presents the current state of knowledge of the Aotearoa New Zealand last interglacial (marine isotope stage 5, MIS 5, sensu lato) sea-level record compiled within the framework of the World Atlas of Last Interglacial Shorelines (WALIS) database. A total of 77 relative sea-level (RSL) indicators (direct, marine-limiting, and terrestrial-limiting points), commonly in association with marine terraces, were identified from over 120 studies reviewed. Extensive coastal deformation around New Zealand has prompted research focused on active tectonics, the scale of which overprints the sea-level record in most regions. The ranges of last interglacial palaeo-shoreline elevations are significant on both the North Island (276.8 ± 10.0 to −94.2 ± 10.6 ma.m.s.l., above mean sea level) and South Island (165.8 ± 2.0 to −70.0 ± 10.3 ma.m.s.l.) and have been used to estimate rates of vertical land movement; however, in many instances there is a lack of adequate description and age constraint for high-quality RSL indicators. Identified RSL indicators are correlated with MIS 5, MIS 5e, MIS 5c, and MIS 5a and indicate the potential for the New Zealand sea-level record to inform sea-level fluctuation and climatic change within MIS 5. The Northland Region of the North Island and southeastern South Island, historically considered stable, have the potential to provide a regional sea-level curve, minimally impacted by glacio- and hydro-isostatic adjustment (GIA) and reflecting near-eustatic fluctuations in a remote location of the South Pacific, across broad degrees of latitude; however, additional records from these regions are needed. Future work requires modern analogue information, heights above a defined sea-level datum, better stratigraphic descriptions, and use of improved geochronological methods. The database presented in this study is available open access at this link: https://doi.org/10.5281/zenodo.4590188 (Ryan et al., 2020a).

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 A Review of MIS 5e Sea-level Proxies around Japan

2020 ◽  
Author(s):  
Evan Tam ◽  
Yusuke Yokoyama
Keyword(s):  
Sea Level ◽  
Stratigraphic Correlation ◽  
Last Interglacial ◽  
Sea Levels ◽  
Carbon 14 ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Data Points ◽  
Tephra Layers ◽  
Mis 5E

Abstract. Sea-level proxies for Marine Isotopic Stage 5e (MIS 5e, ca. 124 ka) are abundant along the Japanese shoreline, and have been documented for over at least the last 60 years. The bulk of these sea-level proxies are identified in Japan as marine terraces, often correlated by stratigraphic relationships to identified tephra layers, or other chronologically interpreted strata. Use of stratigraphic correlation in conjunction with other techniques such as paleontological analysis, tectonic uplift rates, tephra (volcanic ash), Uranium-Thorium (U/Th), Carbon-14 (14C), and Optically Stimulated Luminesce (OSL) dating techniques have connected Japan’s landforms to global patterns of sea-level change. This paper reviews over 60 years of publications containing sea-level proxies correlated to forming during MIS 5e in Japan. Data collected for this review have been added to the World Atlas of Last Interglacial Shorelines (WALIS), following their standardizations on the elements necessary to analyze paleo sea-levels. This paper reviewed over 70 studies, assembling data points for 300+ locations and examining related papers denoting sea-level indicators for MIS 5e. The database compiled for this review review (Tam and Yokoyama, 2020) is available at: https://doi.org/10.5281/zenodo.4294326 .

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.

scholarly journals Mean Sea Level and Tidal Change in Ireland since 1842: A case study of Cork

2021 ◽  
Author(s):  
Gerard McCarthy ◽  
David Pugh ◽  
Robin Edwards ◽  
Peter Hogarth ◽  
Philip Woodworth
Keyword(s):  
Sea Level ◽  
Climate Adaptation ◽  
Tide Gauge ◽  
Essential Element ◽  
Quality Data ◽  
Sea Level Changes ◽  
Mean Sea Level ◽  
Sea Levels ◽  
Isostatic Adjustment ◽  
The Republic

&lt;p&gt;Mean sea levels are changing worldwide, and local tidal changes have been widely reported. Knowledge of regional changes in mean sea level, and local changes in tides are crucial to inform effective climate adaptation. An essential element of this is the availability of accurate observations of sea level. Sea level data in the Republic of Ireland, prior to the establishment of the National Tide Gauge Network in the mid-2000s, is very limited but belies a wealth of historical data available in archival form. In this study, we digitize records located in Cork Harbour, Ireland from 1842 and show how short duration (6 weeks), high quality data, with a large interval (177 years) to the present, can accurately inform tidal and mean sea level changes. We consider error sources in detail and estimate that for M2 the accuracy of these historical measurements is 1% and 2 minutes for amplitude and timing respectively; and our mean sea level estimates are accurate to the centimetre level. Our results show remarkable tidal stability with a 2% change in the amplitude of the M2 component and 4 minute change in the phase over a period of 177 years; and a mean sea level rise of 41 cm in the Cork Harbour area since 1842, approximately in line with global mean sea level trends plus local glacial isostatic adjustment. More broadly, we show that with careful seasonal, nodal, and atmospheric corrections, together with good knowledge of benchmark provenance, these historic, survey-oriented data can accurately inform of sea level changes.&lt;/p&gt;

U-Series Dating of Last Interglacial High Sea Stands: Barbados Revisited

1990 ◽  
Vol 33 (2) ◽  
pp. 129-147 ◽  
Author(s):  
Teh-Lung Ku ◽  
M. Ivanovich ◽  
Shangde Luo
Keyword(s):  
Sea Level ◽  
Uranium Isotopes ◽  
Acropora Palmata ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Sea Levels ◽  
Oxygen Isotope Stage ◽  
Temporal Relationships ◽  
Multiple Measurements ◽  
Level Model

AbstractU-series chronologies of the emerged coral limestone terraces on Barbados, West Indies, together with those of the terraces from New Guinea, have formed the basis for most late Pleistocene eustatic models. The so-called “Barbados sea level model” has been challenged in recent years, however. A major issue is whether during oxygen isotope stage 5e, when Rendezvous Hill reef complex on Barbados Island formed, the sea rose above the present position for one relatively brief period of <10,000 yr, or for two or more periods spanning approximately from 140,000 to 115,000 yr B.P. Evidence for the latter scenario has not come from initial studies of Barbados but from elsewhere; it is also inconclusive because of the dating uncertainties involved. We have carried out careful redeterminations of U-series ages on a suite of 29 Acropora palmata samples systematically collected from four of the lowest terraces on the island. Diagenetic disturbance may have caused the age spreads at some sampling outcrops. A model for the diagenetic exchange of uranium isotopes in coral samples with those in groundwater explains the anomalous 234U/238U ratios in samples with apparently unaltered mineralogy (aragonite) and trace element (Mg and Sr) chemistry. It shows that age dispersions of 5–10% can be engendered by a U exchange coefficient of the order of 10−6 yr−1. The lower-limit terrace ages, estimated from averaging the multiple measurements, are 81,000 ± 2000 yr (Worthing), 105,000 ± 1000 yr (Ventnor), 120,000 ± 2000 yr (Maxwell), and 117,000 ± 3000 yr (Rendezvous Hill). No evidence was found of previously inferred bipartite sea levels centering around 118,000 and 135,000 yr ago. This study documents the need of dating coral with the high precision/sensitivity mass-spectrometric techniques for future resolution of the temporal relationships among sea level changes, climate oscillations, and astronomical forcing—relationships originally addressed by the Barbados sea level model.

scholarly journals The Use of Submerged Speleothems for Sea Level Research in the Mediterranean SeA: A New Perspective Using Glacial- and Hydro-Isostatic Adjustment (Gia)

2021 ◽  
Author(s):  
fabrizio antonioli ◽  
Stefano Furlani ◽  
Paolo Montagna ◽  
Paolo Stocchi
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Accurate Information ◽  
Sea Level Changes ◽  
Isostatic Adjustment ◽  
Regional Sea Level ◽  
Sea Level Variations ◽  
The Mediterranean ◽  
New Perspective ◽  
Mis 5

The investigation of submerged speleothems for sea level studies has made significant contributions to the understanding of the global and regional sea level variations during the Middle and Late Quateranry. This has been especially the case for the Mediterranean Sea, where more than 300 submerged speleothems sampled in 32 caves have been analysed so far. Here, we present a comprehensive review of the results obtained from the study of submerged speleothems since 1978. The studied speleothems cover the last 1.4 Ma and are focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. Results reveal that submerged speleothems represent extraordinary archives providing accurate information on former sea level changes, also considering that the Mediterranean Sea is devoid of any tropical corals since the Miocene. New results from a stalagmite collected at Palinuro (Campania, Italy) characterized by marine overgrowth are also reported. The measured elevations of speleothems are contaminated by the local response to glacial- and hydro-isostatic adjustment (GIA), and thus might significantly deviate from the global eustatic signal. Age and altitude comparation between Mediterranean speleothems, flowstone from Bahamas with local GIA provide a new scenario for MIS 5 and 7 sea level reconstrutions.

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