Raised Coral Terraces at Malakula, Vanuatu, Southwest Pacific, Indicate High Sea Level During Marine Isotope Stage 3

2001 ◽  
Vol 56 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Guy Cabioch ◽  
Linda K. Ayliffe
Keyword(s):  
Sea Level ◽  
Early Stage ◽  
Marine Isotope Stage ◽  
Ionization Mass ◽  
Sea Levels ◽  
Sea Level Fluctuations ◽  
Sw Pacific ◽  
Stage 4 ◽  
Marine Isotope Stage 3 ◽  
Good Agreement

AbstractThe occurrence of a series of raised coral reefs from the uplifted island of Malakula (Vanuatu, SW Pacific) provide an opportunity to examine sea-level fluctuations over at least the past 120,000 years. Thirteen fossil coral samples from Malakula were analyzed by the thermal ionization mass spectrometry (TIMS) U/Th dating technique, yielding information on sea levels during late marine isotope stage 3 and early stage 4. Our findings are in good agreement with sea-level estimates from raised coral terraces in Papua New Guinea and the recent sea-level reconstruction from the deep-sea sedimentary δ18O records. In particular, our coral data appear to confirm that sea levels at about 45,000–50,000 yr B.P. were only 30 to 60 m below the present level. Combined with other evidence of sea-level change, our data provide a strong case for much higher sea levels and therefore markedly reduced continental ice volume at 47,000 to 49,000 years ago.

scholarly journals Marine isotope stage 3 sea level fluctuations: Data synthesis and new outlook

2008 ◽  
Vol 46 (4) ◽  
Author(s):  
M. Siddall ◽  
E. J. Rohling ◽  
W. G. Thompson ◽  
C. Waelbroeck
Keyword(s):  
Sea Level ◽  
Marine Isotope Stage ◽  
Data Synthesis ◽  
Sea Level Fluctuations ◽  
Marine Isotope Stage 3

scholarly journals New constraints on the timing of sea level fluctuations during early to middle marine isotope stage 3

2008 ◽  
Vol 23 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. J. Rohling ◽  
K. Grant ◽  
C. Hemleben ◽  
M. Kucera ◽  
A. P. Roberts ◽  
...  
Keyword(s):  
Sea Level ◽  
Marine Isotope Stage ◽  
Sea Level Fluctuations ◽  
Marine Isotope Stage 3

Revising key parameters for long-term carbon cycle models

2021 ◽  
Author(s):  
Chloé M. Marcilly ◽  
Trond H. Torsvik ◽  
Mathew Domeier ◽  
Dana L. Royer
Keyword(s):  
Sea Level ◽  
Age Distribution ◽  
Silicate Weathering ◽  
Geological Time ◽  
Sea Levels ◽  
Climate Fluctuations ◽  
Climate Gradients ◽  
Sea Level Fluctuations ◽  
Temperature And Precipitation

<p>CO<sub>2</sub> is the most important greenhouse gas in the Earth’s atmosphere and has fluctuated considerably over geological time. However, proxies for past CO<sub>2 </sub>concentrations have large uncertainties and are mostly limited to Devonian and younger times. Consequently, CO<sub>2</sub> modelling plays a key role in reconstructing past climate fluctuations. Facing the limitations with the current CO<sub>2</sub> models, we aim to refine two important forcings for CO<sub>2</sub> levels over the Phanerozoic, namely carbon degassing and silicate weathering.</p><p>Silicate weathering and carbonate deposition is widely recognized as a primary sink of carbon on geological timescales and is largely influenced by changes in climate, which in turn is linked to changes in paleogeography. The role of paleogeography on silicate weathering fluxes has been the focus of several studies in recent years. Their aims were mostly to constrain climatic parameters such as temperature and precipitation affecting weathering rates through time. However, constraining the availability of exposed land is crucial in assessing the theoretical amount of weathering on geological time scales. Associated with changes in climatic zones, the fluctuation of sea-level is critical for defining the amount of land exposed to weathering. The current reconstructions used in<sub></sub>models tend to overestimate the amount of exposed land to weathering at periods with high sea levels. Through the construction of continental flooding maps, we constrain the effective land area undergoing silicate weathering for the past 520 million years. Our maps not only reflect sea-level fluctuations but also contain climate-sensitive indicators such as coal (since the Early Devonian) and evaporites to evaluate climate gradients and potential weatherablity through time. This is particularly important after the Pangea supercontinent formed but also for some time after its break-up.</p><p>Whilst silicate weathering is an important CO<sub>2</sub> sink, volcanic carbon degassing is a major source but one of the least constrained climate forcing parameters. There is no clear consensus on the history of degassing through geological time as there are no direct proxies for reconstructing carbon degassing, but various proxy methods have been postulated. We propose new estimates of plate tectonic degassing for the Phanerozoic using both subduction flux from full-plate models and zircon age distribution from arcs (arc-activity) as proxies.</p><p>The effect of revised modelling parameters for weathering and degassing was tested in the well-known long-term models GEOCARBSULF and COPSE. They revealed the high influence of degassing on CO<sub>2</sub> levels using those models, highlighting the need for enhanced research in this direction. The use of arc-activity as a proxy for carbon degassing leads to interesting responses in the Mesozoic and brings model estimates closer to CO<sub>2 </sub> proxy values. However, from simulations using simultaneously the revised input parameters (i.e weathering and degassing) large model-proxy discrepancies remain and notably for the Triassic and Jurassic.</p><p> </p>

Revisiting marine isotope stage 3 and 5a (MIS3–5a) sea levels within the northwestern Gulf of Mexico

2009 ◽  
Vol 66 (1-2) ◽  
pp. 100-111 ◽  
Author(s):  
Alexander R. Simms ◽  
Regina DeWitt ◽  
Antonio B. Rodriguez ◽  
Kurt Lambeck ◽  
John B. Anderson
Keyword(s):  
Gulf Of Mexico ◽  
Marine Isotope Stage ◽  
Sea Levels ◽  
Marine Isotope Stage 3

scholarly journals Sea level changes along the Turkish coasts of the Black Sea, the Aegean Sea and the Eastern Mediterranean

2000 ◽  
Vol 1 (1) ◽  
pp. 141 ◽  
Author(s):  
B. ALPAR ◽  
E. DOGAN ◽  
H. YUCE ◽  
H. ALTIOK
Keyword(s):  
Sea Level ◽  
Black Sea ◽  
Eastern Mediterranean ◽  
The Black Sea ◽  
Marmara Sea ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Sea Level Fluctuations ◽  
Short Period ◽  
Turkish Straits System

Short, tidal, subtidal, seasonal, secular sea-level variations, sea-level differences and interactions between the basins have been studied, based on the data collected at some permanent and temporary tide gauges located along the Turkish coasts, mostly along the Straits connecting the Marmara Sea to outer seas. Even though the deficiency of sufficient information prevented us to reach the desired results, many pre-existed studies have been improved. Short-period oscillations were clearly identified along the Turkish Strait System and related to their natu-ral periods. The tidal amplitudes are low along the Turkish coasts, except northern Aegean and eastern Mediterranean. The stability of harmonic constants of Samsun and Antalya were examined and most of the long period constituents were found to be unstable. Even the Marmara Sea is not affected from the tidal oscillations of Black and Aegean Seas, some interactions in low frequency band have been detected. Subtidal sea level fluctuations (3-14 day) have relations with the large-scale cyclic atmospheric patterns passing over the Turkish Straits System. Short-term effects of wind on sea level are evident.Seasonal sea-level fluctuations along the Turkish Straits System are in accord with Black Sea's hydrological cycle. The differential range of the monthly mean sea levels between the Black Sea and the Marmara Sea is highly variable; high during spring and early summer and low during fall and winter.On the average, there is a pronounced sea-level difference (55 cm) along the Turkish Straits System. However, the slope is nonlinear, being much steeper in the Strait of Istanbul. This barotrophic pressure difference is one of the most important factors causing the two-layer flow through the system. The topography and hydrodynamics of the straits, the dominant wind systems and their seasonal variations make this flow more complicated. For secular sea level changes, a rise of 3.2 mm/a was computed for Karsiyaka (1935-71) and a steady trend (-0.4 mm /a) has been observed for annual sea levels at Antalya (1935-77). The decreasing trend (-6.9 mm/a) at Samsun is contrary to the secular rising trend of the Black Sea probably because of its rather short monitoring period (1963-77).

scholarly journals The use of piezocone tests for high-resolution stratigraphy of Quaternary sediment sequences in the Brazilian coast

2007 ◽  
Vol 79 (1) ◽  
pp. 153-170 ◽  
Author(s):  
Giuliano de Mio ◽  
Heraldo L. Giacheti
Keyword(s):  
Sea Level ◽  
Sedimentary Environment ◽  
Brazilian Coast ◽  
Level Fluctuation ◽  
Test Results ◽  
Sea Level Fluctuations ◽  
Sedimentary Sequences ◽  
Sea Level Fluctuation ◽  
The Subject ◽  
Good Agreement

Correlations between mapping units of costal sedimentary basin and interpretation of piezocone test results are presented and discussed based on examples from Caravelas strandplain, (State of Bahia), Paranaguá (State of Paraná) and Guarujá bays (State of São Paulo), Brazil. Recognizing that the sedimentary environment was mainly controlled by sea level fluctuations led to the interpretation of transgressive and regressive sedimentary sequences, which is in a good agreement with the sea level fluctuation curves currently accepted for these regions. The interpretation of piezocone test results shows that the sedimentary sequences of Caravelas and Guarujá sites are similar and they have a good correlation to the sea level fluctuation curve accepted for Salvador region, State of Bahia. On the other hand, the piezocone test results from Paranaguá site indicate a different sedimentary sequence from the previous ones, relating to the sea level fluctuation curve accepted for Paranaguá region. The results show the high applicability of piezocone testing for stratigraphical logging and suggest that it is possible to integrate it with other current techniques used for paleo-environmental studies in Brazil, in accordance with recent approaches used in international research on the subject.

Microatoll record for large century-scale sea-level fluctuations in the mid-Holocene

2009 ◽  
Vol 71 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Ke-Fu Yu ◽  
Jian-Xin Zhao ◽  
Terry Done ◽  
Te-Gu Chen
Keyword(s):  
South China Sea ◽  
Sea Level ◽  
Northern South China Sea ◽  
Mass Spectrometric ◽  
Ionization Mass ◽  
Leizhou Peninsula ◽  
Sea Level Fluctuations ◽  
Thermal Ionization Mass ◽  
Definition Of ◽  
Stable Area

AbstractCoral microatolls have been long used as precise indicators of past sea level, but their use for precise definition of detailed sea-level fluctuations is still rare. Here we report twelve high-precision thermal ionization mass spectrometric 230Th ages for twelve rims of five mid-Holocene microatolls from an emerged reef terrace at Leizhou Peninsula, northern South China Sea. This is a tectonically stable area, enabling us to reconstruct both the timing and trajectory of local sea-level fluctuations accurately. The elevations of these microatoll rims and cores were accurately determined relative to the surface of modern living microatolls at the same site. The results indicate that the sea level during the period of 7050–6600 yr bp (years before AD 1950) was about 171 to 219 cm above the present, with at least four cycles of fluctuations. Over this 450 yr interval, sea level fluctuated by 20–40 cm on century scales.

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