Notes on the Shoreline Recession Along the Coast of the Yukon Territory

ARCTIC ◽  
1963 ◽  
Vol 16 (3) ◽  
pp. 195 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Sea Level ◽  
Ice Sheets ◽  
Yukon Territory ◽  
Northern Coast ◽  
Field Observations ◽  
Mackenzie Delta ◽  
Historical Evidence ◽  
Ground Ice ◽  
Fine Grained ◽  
Coastal Retreat

The 150-km.-long stretch of the coast between Herschel Island and the Mackenzie Delta terminates in bluffs cut into Pleistocene silts, sands, and gravels. No bedrock has yet been observed; if present, its occurrence must be very local. The coastal bluffs which are up to 50 m. high, are constantly being undermined by waves and by the melting of numerous thick tabular ground-ice sheets lying close to sea-level. As the ice sheets are found only in fine-grained sediments, coastal retreat is especially rapid long silty to clayey bluffs. Similarly rapid recession has taken place along the northern coast of Alaska and from the Mackenzie Delta east to Langton Bay. It is the purpose of this note to describe some of the geomorphological and historical evidence fo recession of the coast of the Yukon Territory. The field observations were made while the writer was carrying out studies for the Geographical Branch, Department of Mines and Technical Surveys, Ottawa.

Temperature changes and thaw of permafrost adjacent to Richards Island, Mackenzie Delta, N.W.T.

1991 ◽  
Vol 28 (11) ◽  
pp. 1834-1842 ◽  
Author(s):  
Larry D. Dyke
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Sea Water ◽  
Mackenzie Delta ◽  
Temperature Changes ◽  
Sea Floor ◽  
Sea Bottom ◽  
Coastal Retreat ◽  
Water Depths ◽  
Sea Coast

Thawing of ice-bonded sediment below the sea floor accompanies sea-level rise and shoreline retreat along the Beaufort Sea coast. The rate of thaw is primarily controlled by the warm spring and summer discharge of the Mackenzie River, which affects sea-bottom temperatures to water depths of 10–20 m. The intensity of the warming at any one location decreases with depth until continuous sub-0 °C temperatures are encountered. Sea-level rise eventually brings the sea floor into the cold sea-water zone and thawing stops. Therefore thawing is also controlled by the residence time in the warm zone. Sedimentation or scouring can, respectively, slow or accelerate the increase in water depth and thereby modify the rate of thaw progression. This, combined with changes in the rate of coastal retreat, can produce a subbottom frost table with considerable relief. In the extreme, ice bonding within a few metres of the sea floor can be explained by accelerated submergence.

Liquefaction susceptibility maps for the Aqaba–Elat region with projections of future hazards with sea-level rise

2020 ◽  
pp. qjegh2020-039 ◽  
Author(s):  
Abdel-Rahman A. Abueladas ◽  
Tina M. Niemi ◽  
Abdallah Al-Zoubi ◽  
Gideon Tibor ◽  
Mor Kanari ◽  
...  
Keyword(s):  
Sea Level ◽  
Water Table ◽  
Active Faults ◽  
Gulf Of Aqaba ◽  
Susceptibility Map ◽  
Northern Coast ◽  
Borehole Data ◽  
Ground Acceleration ◽  
Liquefaction Susceptibility ◽  
Susceptibility Maps

The cities of Aqaba, Jordan and Elat, Israel are vulnerable to seismic damage because they are built over the active faults of the Dead Sea Transform that are the source of historically destructive earthquakes. A liquefaction susceptibility map was generated for the Aqaba–Elat region. Borehole data from 149 locations and the water table depth were used to calculate effective overburden stress in the Seed–Idriss simplified method. The liquefaction analysis was based on applying a cyclic loading scenario with horizontal peak ground acceleration of 0.3 g in a major earthquake. The liquefaction map, compiled using a GIS platform, shows high and moderate liquefaction susceptibility zones along the northern coast of the Gulf of Aqaba that extend 800 m inland from the shoreline. In Aqaba, several hotels, luxury apartment complexes, archaeological sites, ports and commercial districts are located within high and moderate liquefaction zones. In Elat, the seaport and the coastal hotel district are located within a high susceptibility zone. Most residential areas, schools and hospitals in both cities are located within zones not susceptible to liquefaction based on the methods of this study. The total area with the potential to be liquefied along the Gulf of Aqaba is c. 10 km2. Given predictions for global sea-level, we ran three liquefaction models utilizing projected water table rises of 0.5, 1 and 2 m. These models yielded an increase in the area of high liquefaction ranging from 26 to 49%. Given the high potential of future earthquakes, our liquefaction susceptibility maps should help inform city officials for hazard mitigation planning.

Relative control of bedrock roughness versus topography on global glacier bed friction

2021 ◽  
Author(s):  
Olivier Gagliardini ◽  
Fabien Gillet-Chaulet ◽  
Florent Gimbert
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Inverse Method ◽  
Ad Hoc ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Grid Resolution ◽  
Classical Approach ◽  
Bed Topography ◽  
Bed Friction

<p>Friction at the base of ice-sheets has been shown to be one of the largest uncertainty of model projections for the contribution of ice-sheet to future sea level rise. On hard beds, most of the apparent friction is the result of ice flowing over the bumps that have a size smaller than described by the grid resolution of ice-sheet models. To account for this friction, the classical approach is to replace this under resolved roughness by an ad-hoc friction law. In an imaginary world of unlimited computing resource and highly resolved bedrock DEM, one should solve for all bed roughnesses assuming pure sliding at the bedrock-ice interface. If such solutions are not affordable at the scale of an ice-sheet or even at the scale of a glacier, the effect of small bumps can be inferred using synthetical periodic geometry. In this presentation,<span>  </span>beds are constructed using the superposition of up to five bed geometries made of sinusoidal bumps of decreasing wavelength and amplitudes. The contribution to the total friction of all five beds is evaluated by inverse methods using the most resolved solution as observation. It is shown that small features of few meters can contribute up to almost half of the total friction, depending on the wavelengths and amplitudes distribution. This work also confirms that the basal friction inferred using inverse method<span>  </span>is very sensitive to how the bed topography is described by the model grid, and therefore depends on the size of the model grid itself.<span> </span></p>

scholarly journals Glacial Isostatic Adjustment modelling: historical perspectives, recent advances, and future directions

2018 ◽  
Author(s):  
Pippa L. Whitehouse
Keyword(s):  
Solid Earth ◽  
Sea Level ◽  
Measurement Techniques ◽  
Ice Sheets ◽  
Order Effects ◽  
System Modelling ◽  
Glacial Isostatic Adjustment ◽  
Future Directions ◽  
Historical Perspectives ◽  
Isostatic Adjustment

Abstract. Glacial Isostatic Adjustment (GIA) describes the response of the solid Earth, the gravitational field, and consequently the oceans to the growth and decay of the global ice sheets. It is a process that takes place relatively rapidly, triggering 100 m-scale changes in sea level and solid Earth deformation over just a few tens of thousands of years. Indeed, the first-order effects of GIA could already be quantified several hundred years ago without reliance on precise measurement techniques and scientists have been developing a unifying theory for the observations for over 200 years. Progress towards this goal required a number of significant breakthroughs to be made, including the recognition that ice sheets were once more extensive, the solid Earth changes shape over time, and gravity plays a central role in determining the pattern of sea-level change. This article describes in detail the historical development of the field of GIA and an overview of the processes involved. Significant recent progress has been made as concepts associated with GIA have begun to be incorporated into parallel fields of research; these advances are discussed, along with the role that GIA is likely to play in addressing outstanding research questions within the field of Earth system modelling.

scholarly journals Last Interglacial climate and sea-level evolution from a coupled ice sheet–climate model

2016 ◽  
Vol 12 (12) ◽  
pp. 2195-2213 ◽  
Author(s):  
Heiko Goelzer ◽  
Philippe Huybrechts ◽  
Marie-France Loutre ◽  
Thierry Fichefet
Keyword(s):  
Surface Temperature ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Last Interglacial ◽  
A Minor ◽  
The Antarctic ◽  
The Impact ◽  
And Sea Level

Abstract. As the most recent warm period in Earth's history with a sea-level stand higher than present, the Last Interglacial (LIG,  ∼  130 to 115 kyr BP) is often considered a prime example to study the impact of a warmer climate on the two polar ice sheets remaining today. Here we simulate the Last Interglacial climate, ice sheet, and sea-level evolution with the Earth system model of intermediate complexity LOVECLIM v.1.3, which includes dynamic and fully coupled components representing the atmosphere, the ocean and sea ice, the terrestrial biosphere, and the Greenland and Antarctic ice sheets. In this setup, sea-level evolution and climate–ice sheet interactions are modelled in a consistent framework.Surface mass balance change governed by changes in surface meltwater runoff is the dominant forcing for the Greenland ice sheet, which shows a peak sea-level contribution of 1.4 m at 123 kyr BP in the reference experiment. Our results indicate that ice sheet–climate feedbacks play an important role to amplify climate and sea-level changes in the Northern Hemisphere. The sensitivity of the Greenland ice sheet to surface temperature changes considerably increases when interactive albedo changes are considered. Southern Hemisphere polar and sub-polar ocean warming is limited throughout the Last Interglacial, and surface and sub-shelf melting exerts only a minor control on the Antarctic sea-level contribution with a peak of 4.4 m at 125 kyr BP. Retreat of the Antarctic ice sheet at the onset of the LIG is mainly forced by rising sea level and to a lesser extent by reduced ice shelf viscosity as the surface temperature increases. Global sea level shows a peak of 5.3 m at 124.5 kyr BP, which includes a minor contribution of 0.35 m from oceanic thermal expansion. Neither the individual contributions nor the total modelled sea-level stand show fast multi-millennial timescale variations as indicated by some reconstructions.

The response of large ice sheets to climatic change

1992 ◽  
Vol 338 (1285) ◽  
pp. 235-242 ◽  
Keyword(s):  
Mass Balance ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Mixing Ratio ◽  
Ice Dynamics ◽  
Environmental Models ◽  
Level Change ◽  
The Antarctic

The prediction of short-term (100 year) changes in the mass balance of ice sheets and longer-term (1000 years) variations in their ice volumes is important for a range of climatic and environmental models. The Antarctic ice sheet contains between 24 M km 3 and 29 M km 3 of ice, equivalent to a eustatic sea level change of between 60m and 72m. The annual surface accumulation is estimated to be of the order of 2200 Gtonnes, equivalent to a sea level change of 6 mm a -1 . Analysis of the present-day accumulation regime of Antarctica indicates that about 25% ( ca. 500 Gt a -1 ) of snowfall occurs in the Antarctic Peninsula region with an area of only 6.8% of the continent. To date most models have focused upon solving predictive algorithms for the climate-sensitivity of the ice sheet, and assume: (i) surface mass balance is equivalent to accumulation (i.e. no melting, evaporation or deflation); (ii) percentage change in accumulation is proportional to change in saturation mixing ratio above the surface inversion layer; and (iii) there is a linear relation between mean annual surface air tem perature and saturation mixing ratio. For the A ntarctic Peninsula with mountainous terrain containing ice caps, outlet glaciers, valley glaciers and ice shelves, where there can be significant ablation at low levels and distinct climatic regimes, models of the climate response must be more complex. In addition, owing to the high accumulation and flow rates, even short- to medium -term predictions must take account of ice dynamics. Relationships are derived for the mass balance sensitivity and, using a model developed by Hindmarsh, the transient effects of ice dynamics are estimated. It is suggested that for a 2°C rise in mean annual surface tem perature over 40 years, ablation in the A ntarctic Peninsula region would contribute at least 1.0 mm to sea level rise, offsetting the fall of 0.5 mm contributed by increased accum ulation.

scholarly journals High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)

2010 ◽  
Vol 61 (1) ◽  
pp. 29-38
Author(s):  
Damir Bucković ◽  
Maja Martinuš ◽  
Duje Kukoč ◽  
Blanka Tešović ◽  
Ivan Gušić
Keyword(s):  
Sea Level ◽  
Deep Water ◽  
High Frequency ◽  
Upper Cretaceous ◽  
Distal Part ◽  
Preferential Orientation ◽  
Sea Level Changes ◽  
Carbonate Production ◽  
Fine Grained ◽  
Platform Margin

High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)The upper part of the Middle Coniacian/Santonian-Middle Campanian deep-water Dol Formation of the island of Brač is composed of countless fine-grained allodapic intercalations deposited in an intraplatform trough. Within the studied section 13 beds can be distinguished, each defined by its lower part built up of dark grey limestone with abundance of branched, horizontally to subhorizontally oriented burrows, and the upper part, in which the light grey to white limestone contains larger burrows, rarely branched, showing no preferential orientation. The lower, dark grey, intensively bioturbated levels are interpreted as intervals formed during high-frequency sea-level highstands, while the upper, light grey-to-white levels are interpreted as intervals formed during the high-frequency sea-level lowstands. Cyclic alternation of these two intervals within the fine-grained allodapic beds is interpreted as the interaction between the amount of carbonate production on the platform margin and the periodicity and intensity of shedding and deposition in the distal part of toe-of-slope environment, which is governed by Milankovitch-band high frequency sea-level changes.

Sign in / Sign up

Export Citation Format

Share Document