scholarly journals Compilation of Last Interglacial (Marine Isotope Stage 5e) sea level indicators in the Bahamas, Turks and Caicos, and the east coast of Florida, USA

2021 ◽  
Author(s):  
Andrea Dutton ◽  
Alexandra Villa ◽  
Peter M. Chutcharavan
Keyword(s):  
Sea Level ◽  
Atlantic Coast ◽  
Marine Isotope Stage ◽  
Last Interglacial ◽  
The Bahamas ◽  
The Past ◽  
Subaerial Exposure ◽  
Fossil Corals ◽  
Community Effort ◽  
Mis 5E

Abstract. This paper provides a summary of published sea level archives representing the past position of sea level during the Last Interglacial sea level highstand in the Bahamas, Turks and Caicos, and the eastern (Atlantic) coast of Florida, USA. These data were assembled as part of a community effort to build the World Atlas of Last Interglacial Shorelines (WALIS) database. Shallow marine deposits from this sea level highstand are widespread across the region and are dominated by carbonate sedimentary features. In addition to depositional (constructional) sedimentary indicators of past sea level position, there is also evidence of erosion, dissolution, and/or subaerial exposure in places that can place an upper limit on the position of sea level. The sea level indicators that have been observed within this region and attributed to Marine Isotope Stage (MIS) 5e include corals, oolites, and other coastal sedimentary features. Here we compile a total of 50 relative sea level indicators including 36 in the Bahamas, three in West Caicos, and a remaining 10 for the eastern seaboard of Florida. We have also compiled U-Th age data for 24 fossil corals and 56 oolite samples. While some of these archives have been dated using U-Th disequilibrium methods, amino acid racemization, or optically stimulated luminescence, other features have more uncertain ages that have been deduced in the context of regional mapping and stratigraphy. Sedimentary archives in this region that constrain the elevation of the past position of sea level are associated with uncertainties that range from a couple decimeters to several meters. Across the Bahamas and on West Caicos, one of the observations that emerges from this compilation is that estimation of sea level position in this region during Marine Isotope Stage 5e is complicated by widespread stratigraphic evidence for at least one sea level oscillation. This evidence is defined by submarine features separated by erosion and subaerial exposure, meaning that there were likely multiple distinct peaks in sea level rather than just one. To this end, the timing of these individual sea level indicators becomes important when compiling and comparing data across the region given that different archives may have formed during different sub-orbital peaks in sea level.

scholarly journals A standardized database of Marine Isotope Stage 5e sea-level proxies in southern Africa (Angola, Namibia and South Africa)

2021 ◽  
Vol 13 (3) ◽  
pp. 953-968
Author(s):  
J. Andrew G. Cooper ◽  
Andrew N. Green
Keyword(s):  
Sea Level ◽  
Southern Africa ◽  
Marine Isotope Stage ◽  
Ca 125 ◽  
Future Research ◽  
Last Interglacial ◽  
Widespread Application ◽  
Littoral Sediments ◽  
Data Points ◽  
Mis 5E

Abstract. Evidence for sea-level change during and around Marine Isotope Stage (MIS) 5e (ca. 125 ka) in southern Africa derives from a wide variety of geomorphic and sedimentological sea-level indicators, supported in the past 2 decades by absolute chronological control, particularly on littoral deposits, some of which have a quantifiable relationship to former sea level. In addition to these proxies, data provided by both terrestrial (dune sediments and archaeological remains) and marine (lagoonal and nearshore littoral sediments) limiting points provide broad constraints on sea level. Here, we review publications describing such data points. Using the framework of the World Atlas of Last Interglacial Shorelines, we insert in a standardized database (https://doi.org/10.5281/zenodo.4459297, Cooper and Green, 2020) all the elements available to assess former palaeo-relative sea level (palaeo-RSL) and the chronological constraints associated with them (including uncertainties). Overall, we reviewed 71 studies, from which we extracted 39 sea-level indicators and 26 limiting points. As far as age attribution is concerned, early analysis of molluscs and whole-rock beachrock samples using U series allowed dating of several sea-level indicators during the 1980s, but the more widespread application of optically stimulated luminescence (OSL) dating since 2004 has yielded many more (and more accurate) sea-level indicators from several sites. This has helped resolve the nature and timing of MIS 5e shorelines and has the potential to further elucidate the apparent presence of two or more sea-level peaks at several South African sites during this interval. The standardized sea-level database presented in this paper is the first of its kind for this region. Future research should be directed to improve the stratigraphic description of last interglacial shorelines and to obtain better dating, high-accuracy elevation measurements with better palaeo-RSL interpretation.

scholarly journals Giant boulders and Last Interglacial storm intensity in the North Atlantic

2017 ◽  
Vol 114 (46) ◽  
pp. 12144-12149 ◽  
Author(s):  
Alessio Rovere ◽  
Elisa Casella ◽  
Daniel L. Harris ◽  
Thomas Lorscheid ◽  
Napayalage A. K. Nandasena ◽  
...  
Keyword(s):  
Sea Level ◽  
North Atlantic ◽  
Global Climate ◽  
Last Interglacial ◽  
The Bahamas ◽  
Sea Levels ◽  
Storm Intensity ◽  
The North ◽  
Rising Sea Levels ◽  
Mis 5E

As global climate warms and sea level rises, coastal areas will be subject to more frequent extreme flooding and hurricanes. Geologic evidence for extreme coastal storms during past warm periods has the potential to provide fundamental insights into their future intensity. Recent studies argue that during the Last Interglacial (MIS 5e, ∼128–116 ka) tropical and extratropical North Atlantic cyclones may have been more intense than at present, and may have produced waves larger than those observed historically. Such strong swells are inferred to have created a number of geologic features that can be observed today along the coastlines of Bermuda and the Bahamas. In this paper, we investigate the most iconic among these features: massive boulders atop a cliff in North Eleuthera, Bahamas. We combine geologic field surveys, wave models, and boulder transport equations to test the hypothesis that such boulders must have been emplaced by storms of greater-than-historical intensity. By contrast, our results suggest that with the higher relative sea level (RSL) estimated for the Bahamas during MIS 5e, boulders of this size could have been transported by waves generated by storms of historical intensity. Thus, while the megaboulders of Eleuthera cannot be used as geologic proof for past “superstorms,” they do show that with rising sea levels, cliffs and coastal barriers will be subject to significantly greater erosional energy, even without changes in storm intensity.

scholarly journals A Global Database of Marine Isotope Stage 5a and 5c Marine Terraces and Paleoshoreline Indicators

2021 ◽  
Author(s):  
Schmitty B. Thompson ◽  
Jessica R. Creveling
Keyword(s):  
North America ◽  
Sea Level ◽  
Atlantic Coast ◽  
Marine Isotope Stage ◽  
Tectonic Deformation ◽  
Last Interglacial ◽  
Global Database ◽  
Isostatic Adjustment ◽  
Marine Terraces ◽  
Open Access Database

Abstract. In this review we compile and detail the elevation, indicative meaning, and chronology of Marine Isotope Stage 5a and 5c sea level indicators for 39 sites within three geographic regions: the Pacific coast of North America, the Atlantic coast of North America and the Caribbean, and the remaining globe. These relative sea level indicators, comprised of geomorphic indicators such as marine and coral reef terraces, eolianites, and sedimentary marine and terrestrial limiting facies, facilitate future investigation into Marine Isotope Stage 5a and 5c interstadial paleo-sea level reconstruction, glacial isostatic adjustment, and Quaternary tectonic deformation. The open access database, presented in the format of the World Atlas of Last Interglacial Shorelines (WALIS) database, can be found at https://doi.org/10.5281/zenodo.4426206 (Thompson and Creveling, 2021).

scholarly journals Last interglacial (MIS 5e) sea-level proxies in southeastern South America

2021 ◽  
Vol 13 (1) ◽  
pp. 171-197
Author(s):  
Evan J. Gowan ◽  
Alessio Rovere ◽  
Deirdre D. Ryan ◽  
Sebastian Richiano ◽  
Alejandro Montes ◽  
...  
Keyword(s):  
South America ◽  
Sea Level ◽  
Last Interglacial ◽  
Amino Acid Racemization ◽  
Exceptional Preservation ◽  
Infrared Stimulated Luminescence ◽  
Spin Resonance ◽  
Coastal Deposits ◽  
Mis 5E ◽  
Terrace Level

Abstract. Coastal southeast South America is one of the classic locations where there are robust, spatially extensive records of past high sea level. Sea-level proxies interpreted as last interglacial (Marine Isotope Stage 5e, MIS 5e) exist along the length of the Uruguayan and Argentinian coast with exceptional preservation especially in Patagonia. Many coastal deposits are correlated to MIS 5e solely because they form the next-highest terrace level above the Holocene highstand; however, dating control exists for some landforms from amino acid racemization, U∕Th (on molluscs), electron spin resonance (ESR), optically stimulated luminescence (OSL), infrared stimulated luminescence (IRSL), and radiocarbon dating (which provides minimum ages). As part of the World Atlas of Last Interglacial Shorelines (WALIS) database, we have compiled a total of 60 MIS 5 proxies attributed, with various degrees of precision, to MIS 5e. Of these, 48 are sea-level indicators, 11 are marine-limiting indicators (sea level above the elevation of the indicator), and 1 is terrestrial limiting (sea level below the elevation of the indicator). Limitations on the precision and accuracy of chronological controls and elevation measurements mean that most of these indicators are considered to be low quality. The database is available at https://doi.org/10.5281/zenodo.3991596 (Gowan et al., 2020).

scholarly journals Sensitivity of Red Sea circulation to sea level and insolation forcing during the last interglacial

2011 ◽  
Vol 7 (2) ◽  
pp. 1195-1233 ◽  
Author(s):  
G. Trommer ◽  
M. Siccha ◽  
E. J. Rohling ◽  
K. Grant ◽  
M. T. J. van der Meer ◽  
...  
Keyword(s):  
Sea Level ◽  
Red Sea ◽  
Planktonic Foraminifera ◽  
Gulf Of Aden ◽  
Last Interglacial ◽  
The Holocene ◽  
Circulation Mode ◽  
Monsoon Strength ◽  
Mis 5E ◽  
Mis 5

Abstract. This study investigates the response of Red Sea circulation to sea level and insolation changes during termination II and across the last interglacial, in comparison with termination I and the Holocene. Sediment cores from the central and northern part of the Red Sea were investigated by micropaleontological and geochemical proxies. The recovery of the planktonic foraminiferal fauna following high salinities during MIS 6 took place at similar sea-level stand (~50 m below present day), and with a similar species succession, as during termination I. This indicates a consistent sensitivity of the basin oceanography and the plankton ecology to sea-level forcing. Based on planktonic foraminifera, we find that increased water exchange with the Gulf of Aden especially occurred during the sea-level highstand of interglacial MIS 5e. From MIS 6 to the peak of MIS 5e, northern Red Sea SST increased from 21 °C to 25 °C, with about 3 °C of this increase taking place during termination II. Changes in planktonic foraminiferal assemblages indicate that the development of the Red Sea oceanography during MIS 5 was strongly determined by insolation and monsoon strength. The SW Monsoon summer circulation mode was enhanced during the termination, causing low productivity in northern central Red Sea core KL9, marked by high abundance of G. sacculifer, which – as in the Holocene – followed summer insolation. Core KL11 records the northern tip of the intruding intermediate water layer from the Gulf of Aden and its planktonic foraminifera fauna shows evidence for elevated productivity during the sea-level highstand in the southern central Red Sea. By the time of MIS 5 sea-level regression, elevated organic biomarker BIT values suggest denudation of soil organic matter into the Red Sea and high abundances of G. glutinata, and high reconstructed chlorophyll-a values, indicate an intensified NE Monsoon winter circulation mode. Our results imply that the amplitude of insolation fluctuations, and the resulting monsoon strength, strongly influence the Red Sea oceanography during sea-level highstands by regulating the intensity of water exchange with the Gulf of Aden. These processes are responsible for the observation that MIS 5e/d is characterized by higher primary productivity than the Holocene.

Sea-level driven acceleration in coastal forest retreat

Geology ◽  
2019 ◽  
Vol 47 (12) ◽  
pp. 1151-1155 ◽  
Author(s):  
Nathalie W. Schieder ◽  
Matthew L. Kirwan
Keyword(s):  
Sea Level ◽  
Atlantic Coast ◽  
The United States ◽  
Ecosystem Change ◽  
Coastal Forest ◽  
The Past ◽  
Dead Trees ◽  
Adult Trees ◽  
Primary Determinant ◽  
Global Sea Level

Abstract Ghost forests, consisting of dead trees adjacent to marshes, are a striking feature of low-lying coastal and estuarine landscapes, and they represent the migration of coastal ecosystems with relative sea-level rise (RSLR). Although ghost forests have been observed along many coastal margins, rates of ecosystem change and their dependence on RSLR remain poorly constrained. Here, we reconstructed forest retreat rates using sediment coring and historical imagery at five sites along the Mid-Atlantic coast of the United States, a hotspot for accelerated RSLR. We found that the elevation of the marsh-forest boundary generally increased with RSLR over the past 2000 yr, and that retreat accelerated concurrently with the late 19th century acceleration in global sea level. Lateral retreat rates increased through time for most sampling intervals over the past 150 yr, and modern lateral retreat rates are 2 to 14 times faster than pre-industrial rates at all sites. Substantial deviations between RSLR and forest response are consistent with previous observations that episodic disturbance facilitates the mortality of adult trees. Nevertheless, our work suggests that RSLR is the primary determinant of coastal forest extent, and that ghost forests represent a direct and prominent visual indicator of climate change.

Whole-Rock Aminostratigraphy and Quaternary Sea-Level History of the Bahamas

2000 ◽  
Vol 54 (2) ◽  
pp. 163-173 ◽  
Author(s):  
Paul J. Hearty ◽  
Darrell S. Kaufman
Keyword(s):  
Amino Acid ◽  
Sea Level ◽  
Late Quaternary ◽  
Radiometric Dating ◽  
Glacial Cycles ◽  
The Bahamas ◽  
Stratigraphic Sequence ◽  
Sequence Of Events ◽  
History Of ◽  
Mis 5E

The surficial geology of the tectonically stable Bahamian archipelago preserves one of the most complete records of middle to late Quaternary sea-level-highstand cycles in the world. However, with the exception of deposits from marine isotope substage (MIS) 5e, fossil corals for radiometric dating of this rich stratigraphic sequence are rare. This study utilizes the previously published, independent lithostratigraphic framework as a testing ground for amino acid racemization in whole-rock limestone samples. At least six limestone–soil couplets provide a relative age sequence of events that encompass as many interglacial–glacial cycles. D-Alloisoleucine/L-isoleucine data fall into six clusters, or “aminozones.” On the basis of independent dating and the inferred correlation with global MIS, the ages of several aminozones are known, while the ages of others are calculated from calibrated amino acid geochronology. This study demonstrates the utility of the whole-rock aminostratigraphy method for dating and correlating widespread emergent marine deposits, constitutes the first regional geochronological framework for the Bahamas, and highlights major sea-level events over the past half million years.

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