Late Pleistocene Sea level on the New Jersey Margin: Implications to eustasy and deep-sea temperature

<p>Offshore fresh groundwater reservoirs have been identified on continental shelves in several regions of the world. In many cases, sea-level change over geologic time-scales has been identified as a key factor in the emplacement of these freshwater systems. This numerical study analyzes a range of paleo-hydrogeological conditions on the New Jersey transect during the late Pleistocene, during which vast sections of the shelf were sub-aerially exposed. Coupled variable-density flow and heat transport simulations were conducted on a geologically representative 2D shelf model using SHEMAT-Suite. The model combines sequence stratigraphic interpretation of 2D depth migrated seismic lines and a stochastic facies distribution, with petrophysical properties derived from IODP Expedition 313 well data. The study considers a 60<sub></sub>000 year period of surface meteoric recharge, and the subsequent marine transgression from 12 000 years ago to present-day. A sensitivity analysis is conducted for key factors that influence offshore freshened groundwater emplacement during recharge phase: (1) topography-driven flow, and (2) permeability anisotropy. Systematically introducing anisotropy resulted in a 11 % &#8211; 31 % decrease in emplaced volume relative to the base-case. The results were analysed to determine whether the late Pleistocene sea-level lowstand drove enough freshwater emplacement that can explain the complex present-day observations. All of the simulated scenarios indicate that surface recharge lead to freshening of sediments across the entire transect during this period, even in case of high permeability anisotropy. The observations also suggest that the cyclical flushing and re-salinification of shelf sediments that takes place over glacial &#8211; interglacial cycles is an asymmetrical process, which favours storage of freshened pore fluid in the long run.</p>

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Erratum: Corrigendum: Sea-level and deep-sea-temperature variability over the past 5.3 million years

Nature ◽

10.1038/nature13488 ◽

2014 ◽

Vol 510 (7505) ◽

pp. 432-432 ◽

Cited By ~ 6

Author(s):

E. J. Rohling ◽

G. L. Foster ◽

K. M. Grant ◽

G. Marino ◽

A. P. Roberts ◽

...

Keyword(s):

Sea Level ◽

Deep Sea ◽

Temperature Variability ◽

Sea Temperature ◽

The Past

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Sea-level and deep-sea-temperature variability over the past 5.3 million years

Nature ◽

10.1038/nature13230 ◽

2014 ◽

Vol 508 (7497) ◽

pp. 477-482 ◽

Cited By ~ 278

Author(s):

E. J. Rohling ◽

G. L. Foster ◽

K. M. Grant ◽

G. Marino ◽

A. P. Roberts ◽

...

Keyword(s):

Sea Level ◽

Deep Sea ◽

Temperature Variability ◽

Sea Temperature ◽

The Past

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The response of a simple Antarctic ice-flow model to temperature and sea-level fluctuations over the Cenozoic era

Annals of Glaciology ◽

10.3189/172756407782871413 ◽

2007 ◽

Vol 46 ◽

pp. 69-77 ◽

Cited By ~ 3

Author(s):

C.I. Van Tuyll ◽

R.S.W. Van De Wal ◽

J. Oerlemans

Keyword(s):

Sea Level ◽

Deep Sea ◽

Flow Model ◽

Ice Sheet ◽

Temperature Record ◽

Ice Flow ◽

Antarctic Ice Sheet ◽

Sea Temperature ◽

Ice Volume ◽

The Antarctic

AbstractAn ice-flow model is used to simulate the Antarctic ice-sheet volume and deep-sea temperature record during Cenozoic times. We used a vertically integrated axisymmetric ice-sheet model, including bedrock adjustment. In order to overcome strong numerical hysteresis effects during climate change, the model is solved on a stretching grid. The Cenozoic reconstruction of the Antarctic ice sheet is accomplished by splitting the global oxygen isotope record derived from benthic foraminifera into an ice-volume and a deep-sea temperature component. The model is tuned to reconstruct the initiation of a large ice sheet of continental size at 34 Ma. The resulting ice volume curve shows that small ice caps (<107 km3) could have existed during Paleocene and Eocene times. Fluctuations during the Miocene are large, indicating a retreat back from the coast and a vanishing ice flux across the grounding line, but with ice volumes still up to 60% of the present-day volume. The resulting deep-sea temperature curve shows similarities with the paleotemperature curve derived from Mg/Ca in benthic calcite from 25 Ma till the present, which supports the idea that the ice volume is well reproduced for this period. Before 34 Ma, the reproduced deep-sea temperature is slightly higher than is generally assumed. Global sea-level change turns out to be of minor importance when considering the Cenozoic evolution of the ice sheet until 5 Ma.

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Sea level and deep-sea temperature reconstructions suggest quasi-stable states and critical transitions over the past 40 million years

Science Advances ◽

10.1126/sciadv.abf5326 ◽

2021 ◽

Vol 7 (26) ◽

pp. eabf5326

Author(s):

Eelco J. Rohling ◽

Jimin Yu ◽

David Heslop ◽

Gavin L. Foster ◽

Bradley Opdyke ◽

...

Keyword(s):

Sea Level ◽

Deep Sea ◽

Dynamical Behavior ◽

Linear Scaling ◽

Sea Level Changes ◽

Stable States ◽

Sea Temperature ◽

Ice Volume ◽

The Past ◽

Critical Transitions

Sea level and deep-sea temperature variations are key indicators of global climate changes. For continuous records over millions of years, deep-sea carbonate microfossil–based δ18O (δc) records are indispensable because they reflect changes in both deep-sea temperature and seawater δ18O (δw); the latter are related to ice volume and, thus, to sea level changes. Deep-sea temperature is usually resolved using elemental ratios in the same benthic microfossil shells used for δc, with linear scaling of residual δw to sea level changes. Uncertainties are large and the linear-scaling assumption remains untested. Here, we present a new process-based approach to assess relationships between changes in sea level, mean ice sheet δ18O, and both deep-sea δw and temperature and find distinct nonlinearity between sea level and δw changes. Application to δc records over the past 40 million years suggests that Earth’s climate system has complex dynamical behavior, with threshold-like adjustments (critical transitions) that separate quasi-stable deep-sea temperature and ice-volume states.

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