scholarly journals High interstadial sea levels over the past 420ka from Huon terraces (Papua New Guinea)

2021 ◽  
Author(s):  
Gino de Gelder ◽  
Laurent Husson ◽  
Anne-Morwenn Pastier ◽  
David Fernández-Blanco ◽  
Tamara Pico ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Sea Level ◽  
Papua New Guinea ◽  
New Guinea ◽  
Deformation Pattern ◽  
Glacial Cycle ◽  
Sea Levels ◽  
Global Mean Sea Level ◽  
Global Sea Level ◽  
Geological Constraints

The history of sea level across the Quaternary is essential for assessing past and future climate and geodynamics. Global sea-level reconstructions are typically derived from oxygen isotope curves, but require calibration with geological constraints that are particularly scarce prior to the last glacial cycle (>130 ka). The exceptionally well-preserved coral reef terrace sequence in the Huon Peninsula (Papua New Guinea) may provide such constraints up to ~420 ka, but has never been analysed in its full extent, or with high-resolution topographic data. Here we apply novel geometric approaches to show that the terrace sequence deformation pattern can be approximated by a northward tectonic tilt, and estimate relative sea-level (RSL) for 31 Late Pleistocene periods, including several periods for which no other RSL data exists elsewhere. Supported by reef modelling, these estimates suggest that global mean sea-level curves derived from oxygen isotopes systematically underestimate interstadial sea-level elevations, by up to ~20m. We propose that this discrepancy is either an effect of incorrect oxygen isotope curve calibrations, or that some short-lived sea-level variations are simply not recorded in oxygen isotope ratios.

High-resolution topography of the uplifting Huon Peninsula (Papua New Guinea) reveals high interstadial sea-levels over the past ~400 ka

2021 ◽  
Author(s):  
Gino de Gelder ◽  
Laurent Husson ◽  
Anne-Morwenn Pastier ◽  
Denovan Chauveau ◽  
David Fernández-Blanco ◽  
...  
Keyword(s):  
Coral Reef ◽  
Sea Level ◽  
Papua New Guinea ◽  
Large Scale ◽  
New Guinea ◽  
Sea Levels ◽  
Level Curves ◽  
The Past ◽  
Reef Models ◽  
Global Mean Sea Level

<p>Quaternary sea-level curves provide crucial insights to constrain tectonic and climatic processes, but require calibration with geological constraints that are particularly scarce for cold periods prior to the last glacial-interglacial cycle. To derive such constraints, we re-visit the Huon Peninsula in Papua New Guinea, which is a classic coral reef terrace (CRT) site that was used for the earliest relative sea-level (RSL) curves. We use digital surface models calculated from 0.5m Pleiades satellite imagery to improve RSL constraints, and unlike previous studies, we find that large-scale tilting of the terrace sequence is generally N-directed. This implies that RSL estimates are several meters higher than previously thought for most highstands over the past ~125 ka. We use the large-scale geometry of the terrace sequence to estimate sea-level highstands up to ~400 ka, and our results suggest that global mean sea-level curves derived from oxygen isotopes consistently underestimate sea-level during the relatively cold Marine Isotope Stages 3, 5a, 5c, 6, 9a and 11a, up to ~10-20 m. We use coral reef models to show that our age interpretation is consistent with the overall terrace sequence morphology, and fits between models and topography improve when adjusting sea-level highstands according to our findings.</p>

Quaternary Sea-Level Events on Northern San Clemente Island, California

1983 ◽  
Vol 20 (3) ◽  
pp. 322-341 ◽  
Author(s):  
Daniel R. Muhs
Keyword(s):  
Amino Acid ◽  
Oxygen Isotope ◽  
Sea Level ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Marine Terraces ◽  
Isotope Record ◽  
Global Sea Level ◽  
Age Estimates ◽  
San Clemente Island

Global sea-level changes are expressed in the coastal landforms and deposits of northern San Clemente Island. Stratigraphic, radiometric, amino acid, and pedologic dating techniques have allowed the development of a chronology of sea-level changes for about the last 500,000 yr. A uranium-series date on coral of about 127,000 yr for the 2nd terrace serves as a calibration point for amino acid age estimates of four other mapped terraces. Two of these terraces have age estimates of about 80,000–105,000 yr, another has an age estimate of about 127,000 yr, and the 5th terrace on the west side of the island is estimated to be about 415,000–575,000 yr old. These dates correlate reasonably well with marine terraces dated elsewhere and with stages of the oxygen-isotope record that are thought to represent high stands of the sea. Weakly cemented calcareous dune sands (eolianites) are moderately extensive on northern San Clemente Island and appear to represent low stands of the sea, since calcareous shelf sands were the most likely source. A radiocarbon date of about 22,000 yr suggests that the youngest eolianite was deposited during the last glacial maximum. An older eolianite is estimated to be about 140,000–195,000 yr old based on stratigraphic relations and degree of soil development. The suggested ages for the eolianites also correlate well with oxygen-isotope estimates of low sea levels.

scholarly journals Twenty-first century response of Petermann Glacier, northwest Greenland to ice shelf loss

2020 ◽  
pp. 1-11
Author(s):  
Emily A. Hill ◽  
G. Hilmar Gudmundsson ◽  
J. Rachel Carr ◽  
Chris R. Stokes ◽  
Helen M. King
Keyword(s):  
Sea Level ◽  
First Century ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Sea Levels ◽  
Grounding Line ◽  
Global Mean Sea Level ◽  
Near Future ◽  
Global Mean ◽  
Large Sections

Abstract Ice shelves restrain flow from the Greenland and Antarctic ice sheets. Climate-ocean warming could force thinning or collapse of floating ice shelves and subsequently accelerate flow, increase ice discharge and raise global mean sea levels. Petermann Glacier (PG), northwest Greenland, recently lost large sections of its ice shelf, but its response to total ice shelf loss in the future remains uncertain. Here, we use the ice flow model Úa to assess the sensitivity of PG to changes in ice shelf extent, and to estimate the resultant loss of grounded ice and contribution to sea level rise. Our results have shown that under several scenarios of ice shelf thinning and retreat, removal of the shelf will not contribute substantially to global mean sea level (<1 mm). We hypothesize that grounded ice loss was limited by the stabilization of the grounding line at a topographic high ~12 km inland of its current grounding line position. Further inland, the likelihood of a narrow fjord that slopes seawards suggests that PG is likely to remain insensitive to terminus changes in the near future.

scholarly journals Insar Maps of Land Subsidence and Sea Level Scenarios to Quantify the Flood Inundation Risk in Coastal Cities: The Case of Singapore

2020 ◽  
Vol 12 (2) ◽  
pp. 296 ◽  
Author(s):  
Joao Catalao ◽  
Durairaju Raju ◽  
Giovanni Nico
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Land Subsidence ◽  
Central Area ◽  
Coastal Areas ◽  
Sar Interferometry ◽  
Asia Pacific ◽  
Flood Vulnerability ◽  
Global Mean Sea Level ◽  
Global Sea Level

Global mean sea level rise associated with global warming has a major impact on coastal areas and represents one of the significant natural hazards. The Asia-Pacific region, which has the highest concentration of human population in the world, represents one of the larger areas on Earth being threatened by the rise of sea level. Recent studies indicate a global sea level of 3.2 mm/yr as measured from 20 years of satellite altimetry. The combined effect of sea level rise and local land subsidence, can be overwhelming for coastal areas. The Synthetic Aperture Radar (SAR) interferometry technique is used to process a time series of TerraSAR-X images and estimate the land subsidence in the urban area of Singapore. Interferometric SAR (InSAR) measurements are merged to the Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 sea-level rise scenarios to identify projected inundated areas and provide a map of flood vulnerability. Subsiding rates larger than 5 mm/year are found near the shore on the low flat land, associated to areas recently reclaimed or built. The projected flooded map of Singapore are provided for different sea-level rise scenarios. In this study, we show that local land subsidence can increase the flood vulnerability caused by sea level rise by 2100 projections. This can represent an increase of 25% in the flood area in the central area of Singapore for the RCP4.5 scenario.

Unravelling the conundrum of river response to rising sea-level from laboratory to field. Part II. The Fly-Strickland River system, Papua New Guinea

Sedimentology ◽  
2008 ◽  
Vol 55 (6) ◽  
pp. 1657-1686 ◽  
Author(s):  
GARY PARKER ◽  
TETSUJI MUTO ◽  
YOSHIHISA AKAMATSU ◽  
WILLIAM E. DIETRICH ◽  
J. WESLEY LAUER
Keyword(s):  
Sea Level ◽  
Papua New Guinea ◽  
River System ◽  
New Guinea ◽  
Rising Sea Level

Trends and projections in ice sheet mass balance

2020 ◽  
Author(s):  
Andrew Shepherd ◽  
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Sea Levels ◽  
Global Sea Level

&lt;p&gt;In recent decades, the Antarctic and Greenland Ice Sheets have been major contributors to global sea-level rise and are expected to be so in the future. Although increases in glacier flow and surface melting have been driven by oceanic and atmospheric warming, the degree and trajectory of today&amp;#8217;s imbalance remain uncertain. Here we compare and combine 26 individual satellite records of changes in polar ice sheet volume, flow and gravitational potential to produce a reconciled estimate of their mass balance. &lt;strong&gt;Since the early 1990&amp;#8217;s, ice losses from Antarctica and Greenland have caused global sea-levels to rise by 18.4 millimetres, on average, and there has been a sixfold increase in the volume of ice loss over time. Of this total, 41 % (7.6 millimetres) originates from Antarctica and 59 % (10.8 millimetres) is from Greenland. In this presentation, we compare our reconciled estimates of Antarctic and Greenland ice sheet mass change to IPCC projection of sea level rise to assess the model skill in predicting changes in ice dynamics and surface mass balance. &amp;#160;&lt;/strong&gt;Cumulative ice losses from both ice sheets have been close to the IPCC&amp;#8217;s predicted rates for their high-end climate warming scenario, which forecast an additional 170 millimetres of global sea-level rise by 2100 when compared to their central estimate.&lt;/p&gt;

scholarly journals Monthly Crustal Loading Corrections for Satellite Altimetry

2013 ◽  
Vol 30 (5) ◽  
pp. 999-1005 ◽  
Author(s):  
R. D. Ray ◽  
S. B. Luthcke ◽  
T. van Dam
Keyword(s):  
Sea Level ◽  
Vertical Motion ◽  
Altimeter Data ◽  
Small Contribution ◽  
Satellite Altimeter ◽  
Significant Correction ◽  
Global Mean Sea Level ◽  
Global Sea Level ◽  
Gravity Recovery ◽  
Global Mean

Abstract Satellite altimeter measurements of sea surface height include a small contribution from vertical motion of the seafloor caused by crustal loading. Loading by ocean tides is routinely allowed for in altimeter data processing. Here, loading by nontidal fluids of the atmosphere, ocean, and terrestrial hydrosphere is examined. The crustal deformation can be computed from either geophysical models or from Gravity Recovery and Climate Experiment (GRACE) gravity inversions of mass variability. The loading corrections are found to be very small, rarely exceeding a few millimeters. Nonetheless, they form a significant correction to altimetric determinations of global mean sea level. The correction is most important at the annual cycle and should be accounted for when attempting to balance the global sea level budget.

Human Pleistocene adaptations in the tropical island Pacific: recent evidence from New Ireland, a Greater Australian outlier

Antiquity ◽  
1989 ◽  
Vol 63 (240) ◽  
pp. 548-561 ◽  
Author(s):  
Jim Allen ◽  
Chris Gosden ◽  
J. Peter White
Keyword(s):  
Papua New Guinea ◽  
Late Pleistocene ◽  
Western Australia ◽  
New South ◽  
New Guinea ◽  
Tropical Island ◽  
Sea Levels ◽  
South Wales ◽  
Tropical Lowlands ◽  
New Britain

The late Pleistocene colonization of Greater Australia by humans by c. 40,0130 b.p. is now generally accepted. This landmass, which comprised at periods of lower sea levels Tasmania, Australia and Papua New Guinea, has now produced sites with rich and diverse sequences extending towards or now mainly beyond 30,000 b.p., in the present arid country of western New South Wales (Barbetti & Allen 1972), in southwest Western Australia (Pearce & Barbetti 1981), in the Papua New Guinea Highlands (Gillieson & Mountain 1983), and recently even in Tasmania (Cosgrove 1989).Prior to 1985, with the exception of an 11,000 b.p. date for occupation in Misisjl Cave on New Britain (Specht et al. 1981), the tropical lowlands of Papua New Guinea and its attendant nearer Melanesian island chain had remained a blank on the region’s map of Pleistocene human expansion.

Ecological incumbency impedes stochastic community assembly in Holocene foraminifera from the Huon Peninsula, Papua New Guinea

Paleobiology ◽  
2011 ◽  
Vol 37 (4) ◽  
pp. 670-685 ◽  
Author(s):  
Claire E. Reymond ◽  
Michael Bode ◽  
Willem Renema ◽  
John M. Pandolfi
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Papua New Guinea ◽  
Historical Context ◽  
Neutral Theory ◽  
Stochastic Theory ◽  
New Guinea ◽  
Species Assemblages ◽  
Ecological Communities ◽  
Community Size

Persistence in the structure of ecological communities can be predicted both by deterministic and by stochastic theory. Evaluating ecological patterns against the neutral theory of biodiversity provides an appropriate methodology for differentiating between these alternatives. We traced the history of benthic foraminiferal communities from the Huon Peninsula, Papua New Guinea. From the well-preserved uplifted reef terrace at Bonah River we reconstructed the benthic foraminiferal communities during a 2200-year period (9000–6800 yr B.P.) of reef building during the Holocene transgressive sea-level rise. We found that the similarity of foraminiferal communities was consistently above 60%, even when comparing communities on either side of a massive volcanic eruption that smothered the existing reef system with ash. Similarly, species diversity and rank dominance were unchanged through time. However, similarity dropped dramatically in the final stages of reef growth, when accommodation space was reduced as sea-level rise slowed. We compared the community inertia index (CII) computed from the observed species abundances with that predicted from neutral theory. Despite the differences in foraminiferal community composition in the younger part of the reef sequence, we found an overall greater degree of community inertia with less variance in observed communities than was predicted from neutral theory, regardless of foraminiferal community size or species migration rate. Thus, persistent species assemblages could not be ascribed to neutral predictions. Ecological incumbency of established foraminiferal species likely prevented stochastic increases in both migrant and rare taxa at the Bonah River site. Regardless of the structuring mechanisms, our reconstruction of Holocene foraminiferal assemblages provides historical context for the management and potential restoration of degraded species assemblages.

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