Ice physical properties, structural characteristics and stratigraphy in Hobson’s Choice Ice Island and implications for the growth history of East Ward Hunt Ice Shelf, Canadian High Arctic

1991 ◽  
Vol 37 (126) ◽  
pp. 247-260
Author(s):  
Martin O. Jeffries ◽  
Harold V. Serson ◽  
H. Roy Krouse ◽  
William M. Sackinger
Keyword(s):  
Physical Properties ◽  
Fresh Water ◽  
Size Structure ◽  
Structural Characteristics ◽  
Ice Cores ◽  
Complete Characterization ◽  
Ice Crystal ◽  
Ice Shelf ◽  
Growth History ◽  
History Of

AbstractHobson’s Choice Ice Island is a tabular iceberg that calved in 1982-83 from East Ward Hunt Ice Shelf, N.W.T., Canada. Four ice cores have been analyzed for ice-crystal size, structure and fabric, bulk density, liquid electrical conductivity, δ18O and tritium. This has enabled a complete characterization of the physical properties and the structural characteristics of the ice-shelf component of Hobson’s Choice Ice Island and the first ever study of the stratigraphy and growth history of East Ward Hunt Ice Shelf. The δ18O values range from -34.6 toand indicate that all the ice is derived directly and/or indirectly from precipitation. High tritium values occur only in the lowermost 5 m of the ice shelf in a layer named stratum B. The tritium is anthropogenic and indicates bottom accretion of fresh-water ice since 1952, most likely from fresh water flowing out of Disraeli Fiord below the eastern ice shelf. Above this deepest and youngest ice layer is a 35-38 m thick, unconformable layer (stratum A) comprising three ice types: iced-firn, slush ice and lake ice. This depositional-superimposed ice represents past surface accumulation, which, according to δ18O and ice-crystal structure and size variations, occurred in three major periods, each interrupted by major ablation periods. Fresh water flowing out of Disraeli Fiord below the ice shelf during those warm intervals was the most likely agent responsible for the ablation and eventual complete loss of the original sea-ice platform on which stratum A initially accumulated. The three sub-strata of stratum A vary in thickness from core to core and suggest that there has been an inversion of relief during each ablation period. The different properties and occurrences of the three superimposed ice types are due primarily to past topographic variability.

scholarly journals Ice physical properties, structural characteristics and stratigraphy in Hobson’s Choice Ice Island and implications for the growth history of East Ward Hunt Ice Shelf, Canadian High Arctic

1991 ◽  
Vol 37 (126) ◽  
pp. 247-260 ◽  
Author(s):  
Martin O. Jeffries ◽  
Harold V. Serson ◽  
H. Roy Krouse ◽  
William M. Sackinger
Keyword(s):  
Physical Properties ◽  
Fresh Water ◽  
Size Structure ◽  
Structural Characteristics ◽  
Ice Cores ◽  
Complete Characterization ◽  
Ice Crystal ◽  
Ice Shelf ◽  
Growth History ◽  
History Of

AbstractHobson’s Choice Ice Island is a tabular iceberg that calved in 1982-83 from East Ward Hunt Ice Shelf, N.W.T., Canada. Four ice cores have been analyzed for ice-crystal size, structure and fabric, bulk density, liquid electrical conductivity, δ18O and tritium. This has enabled a complete characterization of the physical properties and the structural characteristics of the ice-shelf component of Hobson’s Choice Ice Island and the first ever study of the stratigraphy and growth history of East Ward Hunt Ice Shelf. The δ18O values range from -34.6 toand indicate that all the ice is derived directly and/or indirectly from precipitation. High tritium values occur only in the lowermost 5 m of the ice shelf in a layer named stratum B. The tritium is anthropogenic and indicates bottom accretion of fresh-water ice since 1952, most likely from fresh water flowing out of Disraeli Fiord below the eastern ice shelf. Above this deepest and youngest ice layer is a 35-38 m thick, unconformable layer (stratum A) comprising three ice types: iced-firn, slush ice and lake ice. This depositional-superimposed ice represents past surface accumulation, which, according to δ18O and ice-crystal structure and size variations, occurred in three major periods, each interrupted by major ablation periods. Fresh water flowing out of Disraeli Fiord below the ice shelf during those warm intervals was the most likely agent responsible for the ablation and eventual complete loss of the original sea-ice platform on which stratum A initially accumulated. The three sub-strata of stratum A vary in thickness from core to core and suggest that there has been an inversion of relief during each ablation period. The different properties and occurrences of the three superimposed ice types are due primarily to past topographic variability.

scholarly journals Small-Scale variability of physical properties and structural characteristics of Antarctic fast ice

1994 ◽  
Vol 20 ◽  
pp. 61-66 ◽  
Author(s):  
A.L. Veazey ◽  
M.O. Jeffries ◽  
K. Morris
Keyword(s):  
Physical Properties ◽  
Structural Characteristics ◽  
Austral Summer ◽  
Ice Cores ◽  
Thin Layers ◽  
Small Scale ◽  
Axis Orientation ◽  
Layer Spacing ◽  
Frazil Ice ◽  
Fast Ice

The small-scale variability of physical properties and structural characteristics of multiple pairs of fast-ice cores obtained during the austral summer of 1991-92 at two Antarctic sites, McMurdo Sound (MCM) and Pine Island Bay (PIB), are examined and discussed with respect to the growth and decay of the sea ice. The ice at the MCM site was thicker than that at the PIB site and was covered by a somewhat thinner snowpack. While mean salinity and temperature of the ice at the two sites were similar, small-scale variations in both salinity and temperature were greater at PIB than at MCM. The ice sheet at MCM was a two-layer medium consisting of congelation ice overlying platelet ice. The ice from the PIB site, however, was composed of mainly frazil ice and layers of congelation ice with occasional thin layers of snow-ice at the surface of the cores. Crystal sub-structure measurements, c-axis orientation and brine-layer spacing from the MCM cores revealed that the congelation ice had moderately aligned, horizontally oriented c axes, suggesting that east-west currents off the southwest tip of Hut Point Peninsula control crystal-growth orientation.d others: Variability of physical and structural characteristics of Antarctic fast ice

scholarly journals Small-Scale variability of physical properties and structural characteristics of Antarctic fast ice

1994 ◽  
Vol 20 ◽  
pp. 61-66 ◽  
Author(s):  
A.L. Veazey ◽  
M.O. Jeffries ◽  
K. Morris
Keyword(s):  
Physical Properties ◽  
Structural Characteristics ◽  
Austral Summer ◽  
Ice Cores ◽  
Thin Layers ◽  
Small Scale ◽  
Axis Orientation ◽  
Layer Spacing ◽  
Frazil Ice ◽  
Fast Ice

The small-scale variability of physical properties and structural characteristics of multiple pairs of fast-ice cores obtained during the austral summer of 1991-92 at two Antarctic sites, McMurdo Sound (MCM) and Pine Island Bay (PIB), are examined and discussed with respect to the growth and decay of the sea ice. The ice at the MCM site was thicker than that at the PIB site and was covered by a somewhat thinner snowpack. While mean salinity and temperature of the ice at the two sites were similar, small-scale variations in both salinity and temperature were greater at PIB than at MCM. The ice sheet at MCM was a two-layer medium consisting of congelation ice overlying platelet ice. The ice from the PIB site, however, was composed of mainly frazil ice and layers of congelation ice with occasional thin layers of snow-ice at the surface of the cores. Crystal sub-structure measurements, c-axis orientation and brine-layer spacing from the MCM cores revealed that the congelation ice had moderately aligned, horizontally oriented c axes, suggesting that east-west currents off the southwest tip of Hut Point Peninsula control crystal-growth orientation.d others: Variability of physical and structural characteristics of Antarctic fast ice

scholarly journals Water Circulation and Ice Accretion Beneath Ward Hunt Ice Shelf (Northern Ellesmere Island, Canada), Deduced From Salinity and Isotope Analysis of Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 68-72 ◽  
Author(s):  
Martin O. Jeffries ◽  
William M. Sackinger ◽  
H. Roy Krouse ◽  
Harold V. Serson
Keyword(s):  
Sea Ice ◽  
Fresh Water ◽  
Sea Water ◽  
Ice Core ◽  
Isotope Analysis ◽  
Ice Cores ◽  
Water Circulation ◽  
Ice Shelf ◽  
The West ◽  
Water Ice

Ice-core drilling and ice-core analysis (electrical conductivity–salinity, 18O, 3H, density) reveal that the internal structure of the west Ward Hunt Ice Shelf contrasts sharply with that of the east ice shelf. The west ice shelf contains a great thickness (≥22 m) of sea ice (mean salinity, 2.22‰; mean δ18O, -0.8‰), whereas the east ice shelf is entirely of meteoric or fresh-water ice (mean salinity 0.01‰; mean δ18O, -29.7‰). High tritium activities are found only in ice from near the bottom of the east and west ice shelves. The contrasting ice-core data is considered to be a proxy record of variations in water circulation and bottom freezing beneath the ice shelf. The west shelf is underlain by sea water flowing into Disraeli Fiord. Sea ice accretes on to the bottom of the west ice shelf from the sea-water flowing into the fiord. Sea-water flowing out of the fiord is directed below the east ice shelf. However, the east ice shelf is not underlain directly by sea-water but by a layer of fresh water from the surface of Disraeli Fiord. In this region, ice growth resulting from the presence of this stable fresh-water layer has been accompanied by surface ablation over a period of perhaps the last 450 years. As a result, fresh-water ice has completely replaced any sea ice that originally grew in the region of the east ice shelf. Whereas the west and east shelves are underlain almost exclusively by sea-water and fresh water, ice in the south shelf is the result of freezing of fresh, brackish or sea water. This is attributed to mixing of the inflowing and outflowing waters.

scholarly journals Water Circulation and Ice Accretion Beneath Ward Hunt Ice Shelf (Northern Ellesmere Island, Canada), Deduced From Salinity and Isotope Analysis of Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 68-72 ◽  
Author(s):  
Martin O. Jeffries ◽  
William M. Sackinger ◽  
H. Roy Krouse ◽  
Harold V. Serson
Keyword(s):  
Sea Ice ◽  
Fresh Water ◽  
Sea Water ◽  
Ice Core ◽  
Isotope Analysis ◽  
Ice Cores ◽  
Water Circulation ◽  
Ice Shelf ◽  
The West ◽  
Water Ice

Ice-core drilling and ice-core analysis (electrical conductivity–salinity, 18O, 3H, density) reveal that the internal structure of the west Ward Hunt Ice Shelf contrasts sharply with that of the east ice shelf. The west ice shelf contains a great thickness (≥22 m) of sea ice (mean salinity, 2.22‰; mean δ18O, -0.8‰), whereas the east ice shelf is entirely of meteoric or fresh-water ice (mean salinity 0.01‰; mean δ18O, -29.7‰). High tritium activities are found only in ice from near the bottom of the east and west ice shelves. The contrasting ice-core data is considered to be a proxy record of variations in water circulation and bottom freezing beneath the ice shelf. The west shelf is underlain by sea water flowing into Disraeli Fiord. Sea ice accretes on to the bottom of the west ice shelf from the sea-water flowing into the fiord. Sea-water flowing out of the fiord is directed below the east ice shelf. However, the east ice shelf is not underlain directly by sea-water but by a layer of fresh water from the surface of Disraeli Fiord. In this region, ice growth resulting from the presence of this stable fresh-water layer has been accompanied by surface ablation over a period of perhaps the last 450 years. As a result, fresh-water ice has completely replaced any sea ice that originally grew in the region of the east ice shelf. Whereas the west and east shelves are underlain almost exclusively by sea-water and fresh water, ice in the south shelf is the result of freezing of fresh, brackish or sea water. This is attributed to mixing of the inflowing and outflowing waters.

MUELLER ALLOY 4640

Alloy Digest ◽  
1979 ◽  
Vol 28 (2) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Fresh Water ◽  
Heat Treating ◽  
Temperature Performance

Abstract MUELLER Alloy 4640 (formerly MBCo Alloy 203) is a classic marine alloy known as Naval Brass. It contains nominally 0.75% tin which has made it the most widely used marine alloy. It is suitable for both salt and fresh water applications. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-366. Producer or source: Mueller Brass Company.

COPPER ALLOY No. C46400

Alloy Digest ◽  
1981 ◽  
Vol 30 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Fresh Water ◽  
Copper Alloy ◽  
Heat Treating ◽  
Temperature Performance ◽  
Strength And Ductility

Abstract Copper Alloy No. C46400 is a classic marine alloy containing nominally 0.8% tin. It has moderate strength and ductility and excellent resistance to corrosion in both salt and fresh water. It is a widely used marine alloy; its many uses include marine hardware, bolts, nuts, propeller shafts, valve stems and condenser plates. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-414. Producer or source: Copper and copper alloy mills.

VALINOX VLX 439L

Alloy Digest ◽  
1992 ◽  
Vol 41 (6) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Stress Corrosion ◽  
Tensile Properties ◽  
Fresh Water ◽  
Stress Corrosion Cracking ◽  
Heat Treating ◽  
Low Carbon ◽  
Boiler Water

Abstract VALINOX VLX 439L is a ferritic stainless steel with 18% chromium, low carbon, and titanium stabilization to present an entirely ferritic structure; resistance to corrosion in fresh water, boiler water, and cooling waters; and an almost freedom from stress-corrosion cracking problems due to chlorinated water. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: SS-531. Producer or source: Vallourec Inc..

SOLEIL C5

Alloy Digest ◽  
1995 ◽  
Vol 44 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Fresh Water ◽  
Martensitic Stainless Steel ◽  
Heat Treating ◽  
Good Corrosion Resistance

Abstract SOLEIL C5 is a 13% chromium 4% nickel martensitic stainless steel with improved toughness and good corrosion resistance to fresh water. Shafts and compressor impellers for hydraulic applications is the area of primary usage. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, and joining. Filing Code: SS-595. Producer or source: Creusot-Marrel.

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