scholarly journals Last Interglacial changes in sea level on Aldabra, western Indian Ocean

Sedimentology ◽  
2020 ◽  
Vol 67 (6) ◽  
pp. 3236-3258
Author(s):  
Colin J. R. Braithwaite
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Western Indian Ocean ◽  
Last Interglacial

scholarly journals Last interglacial sea-level proxies in East Africa and the Western Indian Ocean

2021 ◽  
Vol 13 (4) ◽  
pp. 1633-1651
Author(s):  
Patrick Boyden ◽  
Jennifer Weil-Accardo ◽  
Pierre Deschamps ◽  
Davide Oppo ◽  
Alessio Rovere
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
Sea Level ◽  
Western Indian Ocean ◽  
Last Interglacial ◽  
The North ◽  
Marine Terraces ◽  
Open Access Database ◽  
Eolian Deposits ◽  
Mis 5

Abstract. In this paper, we describe a sea-level database compiled using published last interglacial, Marine Isotopic Stage 5 (MIS 5), geological sea-level proxies within East Africa and the Western Indian Ocean (EAWIO). Encompassing vast tropical coastlines and coralline islands, this region has many occurrences of well-preserved last interglacial stratigraphies. Most notably, islands almost entirely composed of Pleistocene reefs (such as Aldabra, the Seychelles) have provided reliable paleo relative sea-level indicators and well-preserved samples for U-series chronology. Other sea-level proxies include uplifted marine terraces in the north of Somalia and Pleistocene eolian deposits notched by the MIS 5 sea level in Mozambique to tidal notches in luminescence-limited eolian deposits in Mozambique. Our database has been compiled using the World Atlas of Last Interglacial Shorelines (WALIS) interface and contains 58 sea-level indicators and 2 terrestrial-limiting data points. The open-access database is available at https://doi.org/10.5281/zenodo.4302244 (Version 1.03; Boyden et al., 2020).

Last Interglacial Sea-Level Indicators in the Western Indian Ocean

2020 ◽  
Author(s):  
Patrick Boyden ◽  
Jennifer Weil Accardo ◽  
Pierre Deschamps ◽  
Alessio Rovere
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Ice Sheet ◽  
Western Indian Ocean ◽  
Ocean Basin ◽  
Far Field ◽  
Last Interglacial ◽  
Global Average ◽  
The World ◽  
Geological Facies

<p>With global average temperatures 2°C higher than pre-industrial and eustatic sea-level ranging between 5 and 9 m above present, the Last Interglacial is often regarded as a good process-analogue for a future warmer climate.  Large uncertainties are associated with Last Interglacial eustatic sea-level estimations. To quantify these uncertainties through standardization of sea-level metadata, the World Atlas of Last Interglacial Shorelines (WALIS) provides a community-wide standard for documenting the geological context of sea-level indicators and their chronology. By applying this standard, WALIS allows for the quantitative cross-comparison between previous studies, often times separated by decades.</p><p> </p><p>We use WALIS to review published sea-level indicators for the Last Interglacial within the Western Indian Ocean basin. Located in the far field with respect to past glaciations, the Western Indian Ocean has the potential to provide precisely measured and dated sea level proxies, enabling a reliable estimation of maximum eustatic sea level for the Last Interglacial. This, in turn, would allow to better constrain upper boundaries of melting within ice-sheet models. Furthermore, this review highlights localities that should be revisited based on the presence of geological facies indicative of former highstands where not enough detail has been reported or where advanced dating and geodetic techniques can increase the accuracy of metadata.</p>

scholarly journals Last Interglacial sea-level proxies in East Africa and the Western Indian Ocean

2020 ◽  
Author(s):  
Patrick Boyden ◽  
Jennifer Weil-Accardo ◽  
Pierre Deschamps ◽  
Davide Oppo ◽  
Alessio Rovere
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Western Indian Ocean ◽  
Eastern Africa ◽  
Last Interglacial ◽  
Marine Isotopic Stage ◽  
The North ◽  
Aeolian Deposits ◽  
Marine Terraces ◽  
Data Points

Abstract. In this paper, we describe a sea-level database compiled using published Last Interglacial, Marine Isotopic Stage 5 (MIS 5), geological sea-level proxies within Eastern Africa and the Western Indian Ocean (EAWIO). Encompassing vast tropical coastlines and coralline islands, this region has many occurrences of well preserved last interglacial stratigraphies. Most notably, islands almost entirely composed by Pleistocene reefs (such as Aldabra, the Seychelles) have provided reliable paleo relative sea-level indicators and well-preserved samples for U-series chronology. Other sea-level proxies include uplifted marine terraces in the north of Somalia and tidal notches in luminescence limited aeolian deposits in Mozambique. Our database has been compiled using the World Atlas of Last Interglacial Shorelines (WALIS) interface and contains 57 sea-level indicators and 2 terrestrial limiting data points. The database is available open access at https://doi.org/10.5281/zenodo.4043366 (Version 1.02) (Boyden et al., 2020).

Timing of the Last-Interglacial High Sea Level on the Seychelles Islands, Indian Ocean

1999 ◽  
Vol 51 (3) ◽  
pp. 306-316 ◽  
Author(s):  
Carsten Israelson ◽  
Barbara Wohlfarth
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Coralline Algae ◽  
Rock Surface ◽  
Last Interglacial ◽  
Mean Sea Level ◽  
Field Evidence ◽  
Seychelles Islands

AbstractCorals from the Seychelles Islands, Indian Ocean, occur mainly as small coralline algae–vermetid remnants found in cavities adhering to the rock surface, and they rarely attain more than 2 m2 in area. Samples of Goniastrea and Porites from elevations between 1.7 and 6 m above present mean sea level were dated by TIMS 238U–234U–230Th techniques. The ages from well-preserved corals lie between 131,000 and 122,000 yr B.P., in agreement with most other observations of the last-interglacial sea level. Field evidence and dating from high marine limestones from two sections at La Digue Island indicate a period of coral buildup until 131,000 yr B.P., followed by a drop in sea level between 131,000 and 122,000 yr B.P.

Shoreline changes in a rising sea level context: The example of Grande Glorieuse, Scattered Islands, Western Indian Ocean

2016 ◽  
Vol 72 ◽  
pp. 110-119 ◽  
Author(s):  
Laurent Testut ◽  
Virginie Duvat ◽  
Valérie Ballu ◽  
Rui M.S. Fernandes ◽  
Frédéric Pouget ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Western Indian Ocean ◽  
Shoreline Changes ◽  
Rising Sea Level

Relict mangrove stand on Last Interglacial terrace, Christmas Island, Indian Ocean

1988 ◽  
Vol 4 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Colin D. Woodroffe
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Size Structure ◽  
Last Interglacial ◽  
Unusual Location ◽  
Uranium Series ◽  
Breast Height ◽  
Christmas Island ◽  
Uranium Series Dating ◽  
Elevational Range

ABSTRACTA unique stand of mangroves of the genus Bruguiera occurs on the shore terrace at Hosnies Spring, Christmas Island, Indian Ocean. The mangrove stand, of about 0.33 ha, occurs 120 m inland and over an elevational range of 13 m, from 24 to 37 m above sea level. It is flooded by freshwater from a spring which trickles over a partially-cemented calcsinter concretion gravel with mud. Trees reach 30–40 m high, and 80 cm diameter breast height. The size structure is bimodal with few trees in the 10–25 cm dbh size classes, but abundant propagules, seedlings and saplings. The shore terrace contains corals, some in their position of growth, and has been shown by Uranium-series dating to be Last Interglacial in age. Several alternative explanations of how the mangroves reached this site are examined. One explanation is that this stand of mangroves has persisted at the site for approximately 120,000 years since the Last Interglacial. While this cannot be proved it does appear that the stand is relict and is actively regenerating in this unusual location.

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