Last Interglacial fossiliferous sequences from Santiago Island (Cabo Verde Archipelago): the palaeoecology of the Nossa Senhora da Luz section, a rare example of a protected bay in volcanic oceanic islands

2020 ◽  
Author(s):  
Carlos Melo ◽  
José Madeira ◽  
Ricardo S. Ramalho ◽  
Ana C. Rebelo ◽  
Michael Rasser ◽  
...  
Keyword(s):  
Sea Level ◽  
Thick Layer ◽  
Oceanic Islands ◽  
Field Analysis ◽  
Interglacial Period ◽  
Time Interval ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Cabo Verde ◽  
Santiago Island

<p>The world-wide study of the geological record of the Last Interglacial is key to reconstruct the climatic and oceanographic conditions during that time interval. Here we present preliminary results of a comprehensive field analysis of one of the most extensive and least studied Quaternary fossiliferous sequences in Cabo Verde attributed to the Last Interglacial. It is located at Nossa Senhora da Luz, which is a protected inlet at the SE coast of Santiago Island. The studied sequence shows a set of transitions between fluvial and marine environments, and emersion and immersion events within a confined, highly protected bay environment. The presence, in the upper part of the sequence, of a thick layer of very fine-branched rhodoliths indicates particular ecological conditions within this bay (e.g., shallow and turbidity free waters, stable environmental conditions and/or fast growth) that are absent today and presumably played an important role for the presence of particular invertebrate species during that time. The presence of tidal specimens of the clam <em>Senilia senilis</em> in life position at an altitude of ~12m above sea-level allowed a re-interpretation of relative sea-level changes, suggesting that the uplift trend of Santiago Island for the Last Interglacial period onwards (3m/100ky) is possibly 70% lower than previously calculated (10m/100ky). Fossils include five phyla, with molluscs being the most diverse and abundant. Despite the abundance of some species (e.g., the bivalves <em>Saccostrea cuccullata</em>, <em>S. senilis</em>, and <em>Aequipecten opercularis</em>, and the gastropods <em>Persististrombus latus</em> and <em>Thais nodosa</em>), the general biodiversity is low. The presence of <em>S. cuccullata</em> and <em>S. senilis</em>, absent from extant Cabo Verdean faunas, indicates a more humid climate, unlike the dry climate found today. Some horizons are intensively bioturbated with the crustacean burrow <em>Thalassinoides suevicus</em>. Our new data agree with the hypothesised palaeoclimatic framework of more wet conditions than today for the Last Interglacial in the archipelago.</p><p>Keywords: Eemian, Cabo Verde Archipelago, sheltered bay, <em>Senilia senilis</em>, volcanic oceanic islands, NE Atlantic</p><p><strong>Acknowledgments</strong></p><p>C.S.M. and A.C.R. acknowledge, respectively, his PhD grant M3.1.a/F/100/2015 from FRCT/Açores 2020 and her Post-Doc grant SFRH/BPD/117810/2016 by FCT. R.R. and S.Á. acknowledges his IF/01641/2015 and IF/ 00465/2015 grants funded by FCT. A.R. and M.R. were supported by the by DFG grant RA1597/3-1. This work was supported by FCT project PTDC/CTA-GEO/28588/2017 and LISBOA-01-0145-FEDER-028588 UNTIeD and DRCT 2019-2022 – ACORES-01-0145_FEDER-000078 – VRPROTO.</p>

Late Pleistocene Sea Level History of Bermuda

1978 ◽  
Vol 9 (2) ◽  
pp. 205-218 ◽  
Author(s):  
Russell S. Harmon ◽  
Henry P. Schwarcz ◽  
Derek C. Ford
Keyword(s):  
Sea Level ◽  
Interglacial Period ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
The Bahamas ◽  
Sea Level Fluctuations ◽  
Vertical Range ◽  
Level Data ◽  
Last Interglacial Period ◽  
History Of

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.

Interglacial deposits at Bobbitshole, Ipswich

1957 ◽  
Vol 241 (676) ◽  
pp. 1-31 ◽  
Keyword(s):  
Sea Level ◽  
Lacustrine Sediments ◽  
Interglacial Period ◽  
Lake Basin ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Marsh Vegetation ◽  
Sandy Gravel ◽  
North West ◽  
Plant Remains

The stratigraphy and palaeobotany of fresh-water interglacial deposits at Bobbitshole, Ipswich, Suffolk, have been investigated. The interglacial deposits are shown to occupy a lake basin in a valley cut in the local plateau, which is partly formed by a chalky boulder clay assigned to the Gipping ice advance. In this basin was deposited a series of lacustrine sediments, first silt (probably of aeolian origin), then clay-mud and finally clay. These interglacial sediments are sealed unconformably by sandy gravel, probably deposited under cold conditions. Pollen diagrams and macroscopic plant remains from the interglacial deposits are described. They give evidence of the vegetational and climatic history during the first half of an interglacial period. The succession of pollen zones found is similar to that described from the Eemian (Last) Interglacial in north-west Europe, with which the interglacial is correlated. The Eemian pollen zones b , c , d , e and f which show the succession from birch- to pine- to oak-dominated forest, are all present. An analysis of the very abundant macroscopic plant remains, together with the pollen results, suggests a rapid amelioration of the climate at the beginning of the interglacial period, and in zone f , the final zone represented, there are indications of a summer warmth exceeding that of the present day in the area. The interglacial flora is particularly rich in aquatic plants, and an analysis of the abundance of each species indicates a vegetational succession, as the lake filled with sediment, from open-water to reed-swamp to marsh vegetation. The palaeobotany of the deposits is briefly compared with that of other interglacial deposits in Britain and on the continent. The correlation of the interglacial deposits with the continental Eemian (Last) Interglacial provides confirmation of the correlation of the Gipping ice advance with the Saale Glaciation of northern Germany, and indicates that the covering gravels are of Last Glaciation age. The interglacial deposits are partly below sea-level, and close to the tidal Orwell estuary. The significance of this for local relative land- and sea-level changes in and after the interglacial is discussed.

Quaternary evolution and paleoclimatology of the coastal cave of Selinitsa (SW Peloponnese, Greece) based on geomorphological and geochemical data

2021 ◽  
Author(s):  
Isidoros Kampolis ◽  
Vasilios Skliros ◽  
Stavros Triantafyllidis
Keyword(s):  
Sea Level ◽  
Eastern Mediterranean ◽  
Eastern Coast ◽  
Middle Pleistocene ◽  
Interglacial Period ◽  
Level Fluctuation ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Sea Level Fluctuation ◽  
Mis 5E

<p>The present study examines the Quaternary evolution of the Selinitsa coastal cave in SW Peloponnese, in an attempt to provide new insights on the paleogeographical and paleoclimatological conditions of the Eastern Mediterranean Sea. The entrance of Selinitsa Cave is located +18 m above present sea level (a.p.s.l.) on the eastern coast of Messiniakos Gulf (SW Peloponnese), an area of constant uplift since Middle Pleistocene. Considering the phreatic origin of Selinitsa and the presence of sea level indicators at its entrance (biological and geomorphological markers such as tidal notches and <em>Lithophaga</em> borings), all together qualify the cave suitable for the study of former sea level changes and more particularly, those during the last interglacial period. The MIS 5e is considered the most suitable geological period for the estimation of future sea level rise due to the plethora of geological data at-or-near the coastal zone combined to sea-level fluctuation circles from Middle Pleistocene to-date. Previous results from Selinitsa Cave place the sea level of the latest phase of the last interglacial at +18 m a.p.s.l.</p><p>The Eastern Mediterranean is the least studied area relative to the Western Mediterranean, regarding sea level changes during Marine Isotope Stage 5e (MIS 5e). In order to reconstruct the paleogeography of the area and shed light on the climatic conditions of this period, our study involved geological mapping, field measurements and identification of geomorphological features (marine terraces, coastal caves and former sedimentary tidal environments). Additionally, 3D mapping of Selinitsa was conducted in order to precisely define its relative location in respect to the present sea level. Moreover, X-ray diffraction, optical microscopy, mineralogy and major and trace element geochemistry of speleothems and clastic sediments found in the inner part of Selinitsa were also employed and combined to the aforementioned geomorphological data.</p><p>The objective of the study is to provide a model for the development and the paleoclimatic conditions of the Selinitsa Cave during Late Pleistocene, how sea-level affected the aforementioned system, and finally provide an estimate of sea-level fluctuation over the last 125 ka.</p>

WALIS - Towards a global database of Last Interglacial sea-level proxies.

2021 ◽  
Author(s):  
Alessio Rovere ◽  
Deirdre Ryan ◽  
Matteo Vacchi ◽  
Alexander Simms ◽  
Andrea Dutton ◽  
...  
Keyword(s):  
Sea Level ◽  
Research Council ◽  
Geological Data ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Global Database ◽  
The World ◽  
First Results ◽  
Data Points ◽  
The Subject

<p>The standardization of geological data, and their compilation into geodatabases, is essential to allow more coherent regional and global analyses. In sea-level studies, the compilation of databases containing details on geological paleo sea-level proxies has been the subject of decades of work. This was largely spearheaded by the community working on Holocene timescales. While several attempts were also made to compile data from older interglacials, a truly comprehensive approach was missing. Here, we present the ongoing efforts directed to create the World Atlas of Last Interglacial Shorelines (WALIS), a project spearheaded by the PALSEA (PAGES/INQUA) community and funded by the European Research Council (ERC StG 802414). The project aims at building a sea-level database centered on the Last Interglacial (Marine Isotope Stage 5e, 125 ka), a period of time considered as an "imperfect analog" for a future warmer climate. The database is composed of 17 tables embedded into a mySQL framework with a total of more than 500 single fields to describe several properties related to paleo sea-level proxies, dated samples and metadata. In this presentation, we will show the first results of the global compilation, which includes nearly 2000 data points and will discuss its relevance in answering some of the most pressing questions related to sea-level changes in past warmer worlds. </p>

scholarly journals Greenland ice sheet contribution to sea level rise during the last interglacial period: a modelling study driven and constrained by ice core data

2013 ◽  
Vol 9 (1) ◽  
pp. 353-366 ◽  
Author(s):  
A. Quiquet ◽  
C. Ritz ◽  
H. J. Punge ◽  
D. Salas y Mélia
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Intergovernmental Panel ◽  
Orbital Configuration ◽  
Global Sea Level

Abstract. As pointed out by the forth assessment report of the Intergovernmental Panel on Climate Change, IPCC-AR4 (Meehl et al., 2007), the contribution of the two major ice sheets, Antarctica and Greenland, to global sea level rise, is a subject of key importance for the scientific community. By the end of the next century, a 3–5 °C warming is expected in Greenland. Similar temperatures in this region were reached during the last interglacial (LIG) period, 130–115 ka BP, due to a change in orbital configuration rather than to an anthropogenic forcing. Ice core evidence suggests that the Greenland ice sheet (GIS) survived this warm period, but great uncertainties remain about the total Greenland ice reduction during the LIG. Here we perform long-term simulations of the GIS using an improved ice sheet model. Both the methodologies chosen to reconstruct palaeoclimate and to calibrate the model are strongly based on proxy data. We suggest a relatively low contribution to LIG sea level rise from Greenland melting, ranging from 0.7 to 1.5 m of sea level equivalent, contrasting with previous studies. Our results suggest an important contribution of the Antarctic ice sheet to the LIG highstand.

A standardized database of Last Interglacial sea-level indicators in southeast Asia: Records from coral reef terraces in a tectonically complex region

2021 ◽  
Author(s):  
Kathrine Maxwell ◽  
Hildegard Westphal ◽  
Alessio Rovere
Keyword(s):  
Coral Reef ◽  
Southeast Asia ◽  
Sea Level ◽  
Tectonic Setting ◽  
Sea Level Change ◽  
The Philippines ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Level Change ◽  
Se Asia

<p>The Last Interglacial (LIG), as well as other warmer periods in the Earth’s geologic history, provides an analogue for predicted warming conditions in the near future. Analysis of sea-level indicators during this period is important in constraining regional drivers of relative sea-level change (RSL) and in modeling future trajectories of sea-level rise. In southeast Asia, several studies have been done to examine LIG sea-level indicators such as coral reef terraces and tidal notches. A synthesis of the state-of-the-art of the LIG RSL indicators in the region, meanwhile, has yet to be done. We reviewed over 50 published works on the LIG RSL indicators in southeast Asia and used the framework of the World Atlas of Last Interglacial Shorelines (WALIS) in building a standardized database of previously published LIG RSL indicators in the region. In total, we identified 38 unique RSL indicators and inserted almost 140 ages in the database. Available data from Indonesia, the Philippines, and East Timor points to variable elevation of sea-level indicators during the LIG highlighting the complex tectonic setting of this region. Variable uplift rates (from as low as 0.02 to as high as 1.1 m/ka) were reported in the study areas echoing various collision and subduction processes influencing these sites. Although several age constraints and elevation measurements have been provided by these studies, more data is still needed to shed more light on the RSL changes in the region. With this effort under the WALIS framework, we hope to identify gaps in the LIG RSL indicators literature in SE Asia and recognize potential areas that can be visited for future work. We also hope that this initiative will help us further understand the different drivers of past sea-level changes in SE Asia and will provide inputs for projections of sea-level change in the future.</p>

Origin and Geomorphology

2006 ◽  
Author(s):  
Thomas S. Bianchi
Keyword(s):  
Sea Level ◽  
Rate Of Change ◽  
Interglacial Period ◽  
Continental Margins ◽  
Before Present ◽  
Sea Level Changes ◽  
The Past ◽  
Constant Rate ◽  
Geologic Record ◽  
The U.S

Geologically speaking, estuaries are ephemeral features of the coasts. Upon formation, most begin to fill in with sediments and, in the absence of sea level changes, would have life spans of only a few thousand to tens of thousands of years (Emery and Uchupi, 1972; Schubel, 1972; Schubel and Hirschberg, 1978). Estuaries have been part of the geologic record for at least the past 200 million years (My) BP (before present; Williams, 1960; Clauzon, 1973). However, modern estuaries are recent features that only formed over the past 5000 to 6000 years during the stable interglacial period of the middle to late Holocene epoch (0–10,000 y BP), which followed an extensive rise in sea level at the end of the Pleistocene epoch (1.8 My to 10,000 y BP; Nichols and Biggs, 1985). There is general agreement that four major glaciation to interglacial periods occurred during the Pleistocene. It has been suggested that sea level was reduced from a maximum of about 80 m above sea level during the Aftoninan interglacial to 100 m below sea level during the Wisconsin, some 15,000 to 18,000 y BP (figure 2.1; Fairbridge, 1961). This lowest sea level phase is referred to as low stand and is usually determined by uncovering the oldest drowned shorelines along continental margins (Davis, 1985, 1996); conversely, the highest sea level phase is referred to as high stand. It is generally accepted that low-stand depth is between 130 and 150 m below present sea level and that sea level rose at a fairly constant rate until about 6000 to 7000 y BP (Belknap and Kraft, 1977). A sea level rise of approximately 10 mm y−1 during this period resulted in many coastal plains being inundated with water and a displacement of the shoreline. The phenomenon of rising (transgression) and falling (regression) sea level over time is referred to as eustacy (Suess, 1906). When examining a simplified sea level curve, we find that the rate of change during the Holocene is fairly representative of the Gulf of Mexico and much of the U.S. Atlantic coastline (Curray, 1965).

scholarly journals Exceptional warmth and climate instability occurred in the European Alps during the Last Interglacial period

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Paul S. Wilcox ◽  
Charlotte Honiat ◽  
Martin Trüssel ◽  
R. Lawrence Edwards ◽  
Christoph Spötl
Keyword(s):  
Greenhouse Gases ◽  
Fluid Inclusions ◽  
Future Climate ◽  
Swiss Alps ◽  
Interglacial Period ◽  
Time Interval ◽  
European Alps ◽  
Reference Period ◽  
Last Interglacial ◽  
Last Interglacial Period

AbstractWarmer temperatures than today, over a period spanning millennia, most recently occurred in the Last Interglacial period, about 129,000 to 116,000 years ago. Yet, the timing and magnitude of warmth during this time interval are uncertain. Here we present a reconstruction of temperatures in the Swiss Alps over the full duration of the Last Interglacial period based on hydrogen isotopes from fluid inclusions in precisely dated speleothems. We find that temperatures were up to 4.0 °C warmer during the Last Interglacial period than in our present-day reference period 1971 to 1990. Climate instability, including an abrupt cooling event about 125,500 years ago, interrupted this thermal optimum but temperatures remained up to 2.0 °C warmer than the present day. We suggest that higher-elevation areas may be more susceptible to warming relative to lowland areas, and that this may hold also for a future climate forced by increasing levels of greenhouse gases.

scholarly journals The robustness of a simple dynamic model of island biodiversity to geological and eustatic change

2021 ◽  
Author(s):  
Pedro Santos Neves ◽  
Joshua W. Lambert ◽  
Luis Valente ◽  
Rampal S. Etienne
Keyword(s):  
Sea Level ◽  
Simulated Data ◽  
Oceanic Islands ◽  
Sea Level Changes ◽  
Land Bridge ◽  
Sea Level Fluctuations ◽  
Continental Islands ◽  
Island Biodiversity ◽  
And Shifts ◽  
And Sea Level

Aim: Biodiversity on islands is affected by various geo-physical processes and sea-level fluctuations. Oceanic islands (never connected to a landmass) are initially vacant with diversity accumulating via colonisation and speciation, followed by a decline as islands shrink. Continental islands have species upon formation (when disconnected from the mainland) and may have transient land-bridge connections. Theoretical predictions for the effects of these geo-processes on rates of colonisation, speciation and extinction have been proposed, but methods of phylogenetic inference assume only oceanic island scenarios without accounting for island ontogeny, sea-level changes or past landmass connections. Here, we analyse to what extent ignoring geodynamics affects the inference performance of a phylogenetic island model, DAISIE, when confronted with simulated data that violate its assumptions. Location: Simulation of oceanic and continental islands. Methods: We extend the DAISIE simulation model to include: area-dependent rates of colonisation and diversification associated with island ontogeny and sea-level fluctuations, and continental islands with biota present upon separation from the mainland, and shifts in rates to mimic temporary land-bridges. We quantify the error made when geo-processes are not accounted for by applying DAISIE's inference method to geodynamic simulations. Results: We find that the robustness of the model to dynamic island area is high (error is small) for oceanic islands and for continental islands that have been separated for a long time, suggesting that, for these island types, it is possible to obtain reliable results when ignoring geodynamics. However, for continental islands that have been recently or frequently connected, robustness of DAISIE is low, and inference results should not be trusted. Main conclusions: This study highlights that under a large proportion of island biogeographic geo-scenarios (oceanic islands and ancient continental fragments) a simple phylogenetic model ignoring geodynamics is empirically applicable and informative. However, recent connection to the continent cannot be ignored, requiring development of a new inference model.

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