Sea-level history of past interglacial periods from uranium-series dating of corals, Curaçao, Leeward Antilles islands

2012 ◽  
Vol 78 (2) ◽  
pp. 157-169 ◽  
Author(s):  
Daniel R. Muhs ◽  
John M. Pandolfi ◽  
Kathleen R. Simmons ◽  
R. Randall Schumann

AbstractCuraçao has reef terraces with the potential to provide sea-level histories of interglacial periods. Ages of the Hato (upper) unit of the “Lower Terrace” indicate that this reef dates to the last interglacial period, Marine Isotope Stage (MIS) 5.5. On Curaçao, this high sea stand lasted at least 8000 yr (~ 126 to ~ 118 ka). Elevations and age of this reef show that late Quaternary uplift rates on Curaçao are low, 0.026–0.054 m/ka, consistent with its tectonic setting. Ages of ~ 200 ka for corals from the older Cortalein unit of the Lower Terrace correlate this reef to MIS 7, with paleo-sea level estimates ranging from − 3.3 m to + 2.3 m. The estimates are in agreement with those for MIS 7 made from other localities and indicate that the penultimate interglacial period was a time of significant warmth, on a par with the present interglacial period. The ~ 400 ka (MIS 11) Middle Terrace I on Curaçao, dated by others, may have formed from a paleo-sea level of + 8.3 to + 10.0 m, or (less likely) + 17 m to + 20 m. The lower estimates are conservative compared to previous studies, but still require major ice sheet loss from Greenland and Antarctica.

2017 ◽  
Vol 88 (3) ◽  
pp. 409-429 ◽  
Author(s):  
Daniel R. Muhs ◽  
Kathleen R. Simmons

AbstractAlthough uranium series (U-series) ages of growth-position fossil corals are important to Quaternary sea-level history, coral clast reworking from storms can yield ages on a terrace dating to more than one high-sea stand, confounding interpretations of sea-level history. On northern Barbados, U-series ages corals from a thick storm deposit are not always younger with successively higher stratigraphic positions, but all date to the last interglacial period (~127 ka to ~112 ka), Marine Isotope Substage (MIS) 5.5. The storm deposit ages are consistent with the ages of growth-position corals found at the base of the section and at landward localities on this terrace. Thus, in this case, analysis of only a few corals would not have led to an error in interpreting sea-level history. In contrast, a notch cut into older Pleistocene limestone below the MIS 5.5 terrace contains corals that date to both MIS 5.5 (~125 ka) and MIS 5.3 (~108 ka). We infer that the notch formed during MIS 5.3 and the MIS 5.5 corals are reworked. Similar multiple ages of corals on terraces have been reported elsewhere on Barbados. Thus, care must be taken in interpreting U-series ages of corals that are reported without consideration of taphonomy.


1978 ◽  
Vol 9 (2) ◽  
pp. 205-218 ◽  
Author(s):  
Russell S. Harmon ◽  
Henry P. Schwarcz ◽  
Derek C. Ford

The timing of eustatic sea level fluctuations over the vertical range + 15 to −11 m has been deduced from 230Th/234U dating of Bermudan corals and speleothems. On this tectonically stable carbonate island, interglacial periods are characterized by platform submergence, development of patch reefs, and the deposition of littoral and eolian carbonates, whereas glacial periods are times of platform emergence, carbonate diagenesis, soil development, and the deposition of speleothems in caves extending below present sea level. Interglacial periods are observed at about 200,000, 130,000 to 90,000, and 10,000 yr BP to present. The sea level history of the last interglacial period (130,000 to 90,000 yr BP) is complex, consisting of at least two short, distinct episodes of high sea stand (at 125,000 and 97,000 yr BP) superimposed on a longer period of general platform submergence. The sea level data derived from this study are compatible with those from other stable areas such as the Bahamas, but in addition suggest that eustatic sea level changes can be rapid, on the order of 5 to 10 m/1000 yr.


2010 ◽  
Vol 7 (3) ◽  
pp. 3969-3999 ◽  
Author(s):  
C. Albrecht ◽  
H. Vogel ◽  
T. Hauffe ◽  
T. Wilke

Abstract. Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5–263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period. We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling projects. It can be hoped that a more far reaching mollusc fossil record will then be obtained, enabling insight into the early evolutionary history of Lake Ohrid.


Author(s):  
Hans Blumenberg

This chapter discusses Hans Blumenberg's essay “Advancing into Eternal Silence: A Century after the Sailing of the Fram” (1993). This essay was written three years before his death. It offers not just the philosophical reading of an episode in the history of polar expeditions ripe with significance, but draws on an anecdote to muse on the relationship between media-archaeology and nihilism. Blumenberg explains that humans are risky beings, and not just because they seek frontier-pushing adventures like the voyage adrift of the Fram. They are risky for the very reason that their biological origins lie in the narrow span of the last interglacial period, when they learned the ability to cope with life caught between the advancing and receding glaciers; the natural being was now pitted against nature.


Quaternary ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 6
Author(s):  
Christopher Satow ◽  
Katharine M. Grant ◽  
Sabine Wulf ◽  
Hartmut Schulz ◽  
Addison Mallon ◽  
...  

The Eemian was the last interglacial period (~130 to 115 ka BP) to precede the current interglacial. In Eastern Mediterranean marine sediments, it is marked by a well-developed and organic-rich “sapropel” layer (S5), which is thought to reflect an intensification and northward migration of the African monsoon rain belt over orbital timescales. However, despite the importance of these sediments, very little proxy-independent stratigraphic information is available to enable rigorous correlation of these sediments across the region. This paper presents the first detailed study of visible and non-visible (cryptotephra) layers found within these sediments at three marine coring sites: ODP Site 967B (Levantine Basin), KL51 (South East of Crete) and LC21 (Southern Aegean Sea). Major element analyses of the glass component were used to distinguish four distinct tephra events of Santorini (e.g., Vourvoulos eruption) and possible Anatolian provenance occurring during the formation of S5. Interpolation of core chronologies provides provisional eruption ages for the uppermost tephra (unknown Santorini, 121.8 ± 2.9 ka) and lowermost tephra (Anatolia or Kos/Yali/Nisyros, 126.4 ± 2.9 ka). These newly characterised tephra deposits have also been set into the regional tephrostratigraphy to illustrate the potential to precisely synchronise marine proxy records with their terrestrial counterparts, and also contribute to the establishment of a more detailed volcanic history of the Eastern Mediterranean.


2019 ◽  
Vol 220 (1) ◽  
pp. 384-392
Author(s):  
T Pico

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.


1981 ◽  
Vol 15 (3) ◽  
pp. 345-364 ◽  
Author(s):  
B.G. Thom ◽  
G.M. Bowman ◽  
P.S. Roy

AbstractThe geomorphic and stratigraphic history of six coastal embayments has been studied in the vicinity of Newcastle, New South Wales (N.S.W.), Australia, in order to determine modes of deposition, and the degree to which marine and estuarine deposits can be correlated and dated. Each embayment possesses its own distinctive suite of landforms ranging from those dominated by coastal dunes to those in which beach ridges occur. In four of the bays dual sand barriers, comprising an Inner Barrier and an Outer Barrier, provide the framework for correlation between embayments. Six stages are recognized in the deposition of late Quaternary sediments in this area: (i) Pre-Last Interglacial, involving accumulation of separate composite units consisting of estuarine clays and transgressive dune complexes; (ii) Last Interglacial stage during which Inner Barriers were formed; (iii) Last Glacial reworking of barrier and dune sands by westerly winds; (iv) Postglacial Marine Transgression during which the Outer Barriers were initiated; (v) Mid-Holocene stage following cessation of sea-level rise ca. 6000–6500 yr B.P. on this coast, and involving progradation of Outer Barriers in some embayments; and (vi) Late Holocene episodic eolian reworking of dune complexes and Outer Barriers. The relatively high wave and wind energy as well as the tectonic setting of the central N.S.W. coast results in somewhat different geomorphic histories from barrier-island coasts in North America and Europe.


2010 ◽  
Vol 14 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Qingyu Guan ◽  
Baotian Pan ◽  
Na Li ◽  
Qiong Li ◽  
Jundi Zhang ◽  
...  

1986 ◽  
Vol 25 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Aaron Kaufman

The 104 available [230Th/234U] analyses of unrecrystallized corals from stable emerged terraces indicate that the last interglacial period occurred approximately 125,000 yr ago. An estimate is made of the exact duration of this period by accounting for the surprisingly small distribution width observed among the 80 most reliable analyses. This distribution width is compared with those obtained for model populations generated by assuming various characteristic analytical errors and various lengths of the last interglacial period. The results show that (1) if there was only a single rise in sea level, it probably lasted no more than 12,000 yr, in agreement with previous estimates; and (2) if there were two separate rises of sea level, the gap between them must have been less than 7500 yr and not 12,200 as proposed by some authors.


2020 ◽  
Author(s):  
Alexander Robinson ◽  
Emilie Capron ◽  
Jorge Alvarez-Solas ◽  
Michael Bender ◽  
Heiko Goelzer ◽  
...  

<p>There is still no consensus concerning the evolution of the Greenland ice sheet during the Last Interglacial period (LIG, 130-115 kyr ago). Ice cores indicate that the ice sheet survived over most of the continent. Proxy data indicate temperature anomalies of up to 6-8°C. However, under these conditions, models predict almost complete deglaciation. This paradox must be resolved to be able to quantify Greenland’s sea-level contribution during the LIG as well as to understand its sensitivity to future climate change. Here we analyze the available evidence and outline strategies to reconcile modeling and data efforts for Greenland during the LIG.</p>


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