A simulation of continental basin margin sedimentation in response to crustal movements, eustatic sea level change, and sediment accumulation rates

The modern concensus outside of the glaciological community is that “greenhouse” gases, released by human activity, will cause an unprecedented temperature rise over the next 100 years and thereby cause a socially-threatening rise of sea level. With respect to ice the concept is simple: warmer means less. The relationship between glaciers and climate is much more complex than this. Warmer also means more vapour transport and there is ample evidence from both theory and ice-core data that snow accumulation rates in both Greenland and Antarctica were lower during the last glacial period. The problem is whether the increased accumulation rates will be exceeded by increased melting of ice in the ablation areas. Antarctica could play a dominant role because of its size and very low temperatures. Only a small percent of Antarctica will increase its meltwater run-off into the ocean. Furthermore, its dynamic response time is so large that the calving rate will not change over a 200-year period. Most of the increased melt will be absorbed in the firn and the question is how much the snow accumulation rate will increase over the major part of the continent.In the northern hemisphere one has to consider the way in which the warming will manifest itself seasonally. Most of the “forecasts” indicate that most of the warming will occur in the winter rather than the summer. In this case one has to consider the balance between greatly increased winter snowfall rates and only slightly increased summer melt rates. In this respect a review of the snow accumulation and ice melt rates from different glaciers and ice caps in the Canadian Arctic Islands is pertinent. Over the past 20 to 30 years we see no sign of a trend of either side of the balance equation (accumulation, melt). Is this the effect of high noise levels or is there simply no trend?Finally, we review the ground-ice potential in terms of sea-level change. Ground ice may not form a large part of the world's ice reserves but it covers a large area. Both increased snowfall rates in winter, and summer warming will move to increase the thickness of the active layer. This will result in run-off to the oceans.Global circulation models might be modified to determine a “best guess” of future sea-level change. To do this they must incorporate all of the parameters considered in this paper.

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Climatic Warming, Glaciers and Sea Level

Annals of Glaciology ◽

10.1017/s0260305500009083 ◽

1990 ◽

Vol 14 ◽

pp. 343 ◽

Cited By ~ 1

Author(s):

R.M Koerner ◽

D.A. Fisher

Keyword(s):

Sea Level ◽

Accumulation Rate ◽

Sea Level Change ◽

Snow Accumulation ◽

Accumulation Rates ◽

Ground Ice ◽

Ample Evidence ◽

Level Change ◽

Global Circulation Models ◽

Run Off

The modern concensus outside of the glaciological community is that “greenhouse” gases, released by human activity, will cause an unprecedented temperature rise over the next 100 years and thereby cause a socially-threatening rise of sea level. With respect to ice the concept is simple: warmer means less. The relationship between glaciers and climate is much more complex than this. Warmer also means more vapour transport and there is ample evidence from both theory and ice-core data that snow accumulation rates in both Greenland and Antarctica were lower during the last glacial period. The problem is whether the increased accumulation rates will be exceeded by increased melting of ice in the ablation areas. Antarctica could play a dominant role because of its size and very low temperatures. Only a small percent of Antarctica will increase its meltwater run-off into the ocean. Furthermore, its dynamic response time is so large that the calving rate will not change over a 200-year period. Most of the increased melt will be absorbed in the firn and the question is how much the snow accumulation rate will increase over the major part of the continent. In the northern hemisphere one has to consider the way in which the warming will manifest itself seasonally. Most of the “forecasts” indicate that most of the warming will occur in the winter rather than the summer. In this case one has to consider the balance between greatly increased winter snowfall rates and only slightly increased summer melt rates. In this respect a review of the snow accumulation and ice melt rates from different glaciers and ice caps in the Canadian Arctic Islands is pertinent. Over the past 20 to 30 years we see no sign of a trend of either side of the balance equation (accumulation, melt). Is this the effect of high noise levels or is there simply no trend? Finally, we review the ground-ice potential in terms of sea-level change. Ground ice may not form a large part of the world's ice reserves but it covers a large area. Both increased snowfall rates in winter, and summer warming will move to increase the thickness of the active layer. This will result in run-off to the oceans. Global circulation models might be modified to determine a “best guess” of future sea-level change. To do this they must incorporate all of the parameters considered in this paper.

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Late Quaternary sea levels and crustal movements, coastal British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/e82-048 ◽

1982 ◽

Vol 19 (3) ◽

pp. 597-618 ◽

Cited By ~ 155

Author(s):

John Clague ◽

John R. Harper ◽

R. J. Hebda ◽

D. E. Howes

Keyword(s):

British Columbia ◽

Sea Level ◽

Late Holocene ◽

Late Quaternary ◽

Sea Level Change ◽

Vancouver Island ◽

Relative Sea Level ◽

Crustal Movements ◽

Level Change ◽

Queen Charlotte Islands

Late Quaternary sea-level fluctuations on the British Columbia coast have been established from studies of terrestrial and marine sediments and landforms. These studies indicate that the sea-level history of mainland British Columbia and eastern Vancouver Island is very different from that of the Queen Charlotte Islands and western Vancouver Island. Specifically, in the former areas, there was a rapid rise of submerged coastal lowlands between about 13 000 and 10 000 years ago. Emergence culminated about 6000–9000 years ago, depending on the locality, when the sea, relative to the land, was 12 m or more lower than at present in some areas. During middle and late Holocene time, relative sea level rose on the mainland coast and at least locally on eastern Vancouver Island, resulting in inundation of coastal archaeological sites and low-lying terrestrial vegetation. Tidal records and precise levelling suggest ongoing submergence of at least part of this region.In contrast, shorelines on the Queen Charlotte Islands were below present from before 13 700 years ago until approximately 9500–10 000 years ago. A transgression at the close of the Pleistocene climaxed about 7500–8500 years ago when relative sea level probably was about 15 m above present in most areas. Most of the emergence that followed apparently occurred in the last 5000–6000 years. There has been a similar pattern of emergence on the west coast of Vancouver Island during late Holocene time.The above patterns of late Quaternary sea-level change are attributed to complex isostatic response to downwasting and retreat of the late Wisconsin Cordilleran Ice Sheet, to transfers of water from melting ice sheets to oceans, and to plate interactions on the British Columbia continental margin. Late Pleistocene and early Holocene crustal movements were dominantly isostatic. Although the recent regression on the outer coast likely is due, at least in part, to tectonic uplift, some late Holocene sea-level change in this area and elsewhere on the British Columbia coast may be either eustatic in nature or a residual isostatic response to deglaciation, which occurred thousands of years earlier.

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SEA-LEVEL CHANGE AND LATE QUATERNARY SEDIMENT ACCUMULATION ON THE SOUTHERN MAINE INNER CONTINENTAL SHELF

Quaternary Coasts of the United States ◽

10.2110/pec.92.48.0023 ◽

1992 ◽

pp. 23-34 ◽

Cited By ~ 7

Author(s):

JOSEPH T. KELLEY ◽

STEPHEN M. DICKSON ◽

DANIEL F. BELKNAP ◽

ROBERT STUCKENRATH

Keyword(s):

Continental Shelf ◽

Sea Level ◽

Late Quaternary ◽

Sediment Accumulation ◽

Sea Level Change ◽

Quaternary Sediment ◽

Level Change ◽

Inner Continental Shelf

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GRACE observing a small scale ocean mass increase in the Bohai Sea

10.5194/egusphere-egu2020-193 ◽

2020 ◽

Author(s):

Dapeng Mu ◽

Tianhe Xu

Keyword(s):

Sea Level ◽

Spatial Resolution ◽

Bohai Sea ◽

Sediment Accumulation ◽

Sea Level Change ◽

Groundwater Depletion ◽

The Bohai Sea ◽

Level Change ◽

Ocean Mass ◽

Mass Increase

<p>The Gravity Recovery and Climate Experiment (GRACE) satellite mission has profoundly advanced our knowledge of contemporary sea level change. Owing to the coarse spatial resolution and leakage issue across the land-ocean boundary, it is challenged for GRACE to detect mass changes over a region smaller than its spatial resolution, especially a semi-enclosed basin that is adjacent to land with significant mass variation. In this contribution, we find that GRACE is capable of recovering mass increase in the Bohai Sea, which is adjacent to the North China Plain that has been experiencing significant groundwater depletion. This water mass increase, only amounting to 0.45 Gt/yr, is demonstrated by a reconstruction that is implemented with multisource data, including altimeter observations, steric estimates, and hydrology model. The reconstructed mass signal rejects the detection of sediment accumulation by GRACE, but it does not exclude the possibility that sediment accumulation may occur at local scale. Compared with the &#8220;true&#8221; mass increase, the mass increase observed by GRACE spherical harmonic coefficients (SHCs) is seriously compromised (i.e., signal magnitudes are substantially reduced) due to leakage issue. Our reconstruction results exemplify that elaborate data-processing is necessary for specific cases. On the other hand, the recently released mascons, which are resolved with constraints and require no further processing, suggest improved seasonal cycles in the Bohai Sea that are in agreement with altimeter observations. However, the rates derived from the mascons cannot properly represent the real ocean mass increase for the Bohai Sea, because the mascons underestimate the rates or contain some artificial effect. Nevertheless, the mascons provide new insights into regional sea level change relative to the traditional SHCs.</p>

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Significant continental ice volumes on mid-Paleocene Antarctica? Latitudinal temperature gradients, sea level change and the carbon cycle

Rendiconti online della Società Geologica Italiana ◽

10.3301/rol.2014.30 ◽

2014 ◽

Vol 31 ◽

pp. 31-32

Author(s):

Peter Bijl

Keyword(s):

Carbon Cycle ◽

Sea Level ◽

Sea Level Change ◽

Temperature Gradients ◽

Level Change

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Phanerozoic Oxygen

10.23943/princeton/9780691145020.003.0011 ◽

2017 ◽

Author(s):

Donald Eugene Canfield

Keyword(s):

Oxygen Consumption ◽

Organic Carbon ◽

Sea Level ◽

Time Scale ◽

Atmospheric Oxygen ◽

Sea Level Change ◽

Oxygen Production ◽

Level Change ◽

History Of ◽

Geologic Processes

This chapter discusses the modeling of the history of atmospheric oxygen. The most recently deposited sediments will also be the most prone to weathering through processes like sea-level change or uplift of the land. Thus, through rapid recycling, high rates of oxygen production through the burial of organic-rich sediments will quickly lead to high rates of oxygen consumption through the exposure of these organic-rich sediments to weathering. From a modeling perspective, rapid recycling helps to dampen oxygen changes. This is important because the fluxes of oxygen through the atmosphere during organic carbon and pyrite burial, and by weathering, are huge compared to the relatively small amounts of oxygen in the atmosphere. Thus, all of the oxygen in the present atmosphere is cycled through geologic processes of oxygen liberation (organic carbon and pyrite burial) and consumption (weathering) on a time scale of about 2 to 3 million years.

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