A new Holocene record from a far-field site in the Indian Ocean to constrain Holocene sea level.

2021 ◽  
Author(s):  
Geoff Richards ◽  
Jedrzej Majewski ◽  
Christabel Tan ◽  
Fangyi Tan ◽  
Tanghua Li ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Late Holocene ◽  
Far Field ◽  
Glacial Isostatic Adjustment ◽  
Field Site ◽  
Isostatic Adjustment ◽  
The Indian Ocean ◽  
Holocene Record ◽  
Full Consideration

<p>Reconstructions of relative sea level (RSL) during the Holocene provide important constraints for Glacial Isostatic Adjustment (GIA) models, determining Earth rheology, estimating ice-equivalent meltwater input, and fingerprinting sources of ice mass loss. In far-field regions such as the Indian Ocean, RSL is characterized by rapid rise during the early Holocene driven primarily by deglaciation of northern hemisphere ice sheets. This cumulated to a characteristic mid-Holocene highstand before falling towards present driven by hydro-isostatic processes. Reconstructions of RSL utilize proxy sea-level indicators to produce sea-level index points (SLIPs) that position RSL in time and space with an associated temporal and vertical uncertainty.</p><p>Here we present a standardized RSL database with a full consideration of uncertainty from the Maldives to investigate regional variations in the characteristics of the mid Holocene highstand, and to constrain the eustatic contribution to RSL change during the mid and late Holocene.</p><p>We produce new SLIPs from a mangrove forest in Kelaa, part of the Haa Alif Atoll in the northern area of the Maldives. We subsampled for mangrove macro fossils suitable for radiocarbon dating and obtained 5 dates with calibrated ages ranging between 630 – 1340 years BP. These new SLIPs show RSL was between 0.07m – -0.14m during this period.</p>

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.

Parameters controlling mid-Holocene highstand in Glacial Isostatic Adjustment modelling

2021 ◽  
Author(s):  
Tanghua Li ◽  
Stephen Chua ◽  
Nicole Khan ◽  
Patrick Wu ◽  
Benjamin Horton
Keyword(s):  
Southeast Asia ◽  
Sea Level ◽  
Late Holocene ◽  
Ice Sheets ◽  
Thickness Variation ◽  
Glacial Isostatic Adjustment ◽  
Lithospheric Thickness ◽  
Isostatic Adjustment ◽  
Mantle Viscosity ◽  
Open Questions

<p>Holocene relative sea-level (RSL) records from regions distal from ice sheets (far-field) are commonly characterized by a mid-Holocene highstand, when RSL reached higher than present levels. The magnitude and timing of the mid-Holocene highstand varies spatially due to hydro-isostatic processes including ocean syphoning and continental levering. While there are open questions regarding the timing, magnitude and source of ice-equivalent sea level in the middle to late Holocene.</p><p>Here, we compare Glacial Isostatic Adjustment (GIA) model predictions to a standardized database of sea-level index points (SLIPs) from Southeast Asia where we have near-complete Holocene records. The database has more than 130 SLIPs that span the time period from ~9.5 ka BP to present. We investigate the sensitivity of mid-Holocene RSL predictions to GIA parameters, including the lateral lithospheric thickness variation, mantle viscosity (both 1D and 3D), and deglaciation history from different ice sheets (e.g., Laurentide, Fennoscandia, Antarctica).</p><p>We compute gravitationally self-consistent RSL histories for the GIA model with time dependent coastlines and rotational feedback using the Coupled Laplace-Finite Element Method. The preliminary results show that the timing of the highstand is mainly controlled by the deglaciation history (ice-equivalent sea level), while the magnitude is dominated by Earth parameters (e.g., lithospheric thickness, mantle viscosity). We further investigate whether there is meltwater input during middle to late Holocene and whether the RSL records from Southeast Asia can reveal the meltwater source, like Antarctica.</p>

A below-the-present late Holocene relative sea level and the glacial isostatic adjustment during the Holocene in the Malay Peninsula

2018 ◽  
Vol 201 ◽  
pp. 206-222 ◽  
Author(s):  
Cheuk-Yan Tam ◽  
Yongqiang Zong ◽  
Kamaludin bin Hassan ◽  
Hamlee bin Ismal ◽  
Habibah binti Jamil ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Glacial Isostatic Adjustment ◽  
Malay Peninsula ◽  
Relative Sea Level ◽  
The Holocene ◽  
Isostatic Adjustment

Sea level and coral atolls: Late Holocene emergence in the Indian Ocean

Geology ◽  
1990 ◽  
Vol 18 (1) ◽  
pp. 62 ◽  
Author(s):  
Colin Woodroffe ◽  
Roger McLean ◽  
Henry Polach ◽  
Eugene Wallensky
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Late Holocene ◽  
The Indian Ocean

scholarly journals A new Holocene sea-level record for Singapore

The Holocene ◽  
2021 ◽  
pp. 095968362110190
Author(s):  
Stephen Chua ◽  
Adam D Switzer ◽  
Tanghua Li ◽  
Huixian Chen ◽  
Margaret Christie ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Ice Sheets ◽  
Early Holocene ◽  
Glacial Isostatic Adjustment ◽  
Present Level ◽  
Isostatic Adjustment ◽  
Model Predictions ◽  
Regional Processes ◽  
Holocene Sea Level

Relative sea-level (RSL) records from far-field regions distal from ice sheets remain poorly understood, particularly in the early Holocene. Here, we extended the Holocene RSL data from Singapore by producing early Holocene sea-level index points (SLIPs) and limiting dates from a new ~40 m sediment core. We merged new and published RSL data to construct a standardized Singapore RSL database consisting of 88 SLIPs and limiting data. In the early Holocene, RSL rose rapidly from −21.0 to −0.7 m from ~9500 to 7000 cal. yrs. BP. Thereafter, the rate of RSL rise decelerated, reaching a mid-Holocene highstand of 4.0 ± 4.5 m at 5100 cal. yrs. BP, before falling to its present level. There is no evidence of any inflections in RSL when the full uncertainty of SLIPs is considered. When combined with other standardized data from the Malay-Thai Peninsula, our results also show substantial misfits between regional RSL reconstructions and glacial isostatic adjustment (GIA) model predictions in the rate of early Holocene RSL rise, the timing of the mid-Holocene highstand and the nature of late-Holocene RSL fall towards the present. It is presently unknown whether these misfits are caused by regional processes, such as subsidence of the continental shelf, or inaccurate parameters used in the GIA model.

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.

Observations of postglacial uplift at Churchill, Manitoba

1992 ◽  
Vol 29 (11) ◽  
pp. 2418-2425 ◽  
Author(s):  
A. Mark Tushingham
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Isostatic Adjustment ◽  
Tide Gauge Record ◽  
Isostatic Adjustment ◽  
Absolute Gravimetry ◽  
The Earth ◽  
Level Data

Churchill, Manitoba, is located near the centre of postglacial uplift caused by the Earth's recovery from the melting of the Laurentide Ice Sheet. The value of present-day uplift at Churchill has important implications in the study of postglacial uplift in that it can aid in constraining the thickness of the ice sheet and the rheology of the Earth. The tide-gauge record at Churchill since 1940 is examined, along with nearby Holocene relative sea-level data, geodetic measurements, and recent absolute gravimetry measurements, and a present-day rate of uplift of 8–9 mm/a is estimated. Glacial isostatic adjustment models yield similar estimates for the rate of uplift at Churchill. The effects of the tide-gauge record of the diversion of the Churchill River during the mid-1970's are discussed.

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