Wyniki wyszukiwania - BazTech

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Iceberg Melting and Climate Change in NW Atlantic Waters

Perez-Gruszkiewicz S.E., Peterson W.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2018

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Vol. 12, no. 3

459--467

EN

Climate change is predicted to cause increases in sea surface temperature (SST), as well as decreases in sea-ice cover, wind and current velocities. These changes will have a marked effect on iceberg melting in the shipping lanes off Newfoundland and Labrador, Canada. Icebergs that today can cross from northern Labrador to Newfoundland without melting will in the future have to be much larger to survive the transit. For example, icebergs at N Labrador in December of 2016 that are smaller than 156 m will melt before reaching 48N, but in year 2100 the length increases to 228 m. In addition, if future iceberg size distributions off Labrador are the same as today, icebergs will experience roughly 50% reductions in numbers in the NW Atlantic shipping lanes by year 2100. The increased melting rates are due to, in order of importance, increased sea-surface temperatures (responsible for 66% of the increase in the minimum transit size), decreasing current velocities (31%), and decreasing sea-ice cover (3%). Decreasing sea-ice tends to increase wave heights as well as accelerate the effects of wave erosion; however, for the areas studied the wave height is predicted to decrease moderately in year 2100, by a maximum of about 10% in December.

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Wstępne wyniki badań petrograficznych archaicznych gnejsów Uivak (Prowincja Nain, Labrador)

Sałacińska A., Kusiak M. A.

Przegląd Geologiczny

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2017

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Vol. 65, nr 6

383--391

EN

The Saglek Block of the Nain Complex in Northern Labrador forms the westernmost part of the North Atlantic Craton. It is one of the few regions on Earth where early Archaean crust is preserved. It consists of regionally metamorphosed gneisses to either granulite-facies from 2.74 to 2.71 Ga or amphibolite-facies at ca. 2.70 Ga. The Saglek Block is dominated by two suites of metaigneous gneisses: the Uivak I TTG suite (>3.6 Ga) and the Uivak II augen gneisses (ca. 3.4 Ga). Four samples offelsic Uivak I orthogneiss were selected to petrographi- cal and mineralogical studies: Johannes Point Cove (L1419), TigigakyukInlet (L1434; L1440) and Big Island (L1443). Sample composition (granodiorite-tonalite) and mineralogy (mostly plagioclase and quartz, with minor K-feldspar and biotite, and accessory zircon and apatite) for three of the four samples are consistent with published data of the Uivak I gneiss. Sample L1434 contains ferroean diopside and hornblende, which are absent in the other samples. Based on detailed mineralogical analyses, authors concluded that more mafic sample, can not belong to the suite of the Uivak I gneisses. Most probably it represents the younger Uivak II. Further, geochronological study is going to be conducted to characterise both, Uivak I and Uivak II gneisses isotopically.

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W poszukiwaniu fragmentów najstarszej skorupy kontynentalnej na Labradorze

Kusiak M. A., Sałacińska A.

Przegląd Geologiczny

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2016

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Vol. 64, nr 11

896--901

EN

There are few unresolved questions in the Earth Sciences which generate as much debate as the nature of the Hadean Earth: i.e. the rock record between the Earth’s formation and about 3.8 billion years ago. Current knowledge of the nature and origin of the earliest crust comes largely from studies of the mineral zircon (ZrSiO4). The oldest zircon grains on Earth (4.46 Ga) are found in Jack Hills, Australia. They represent a time capsule of what the Earth was like from ca. 4.4-4.0 Ga during the Hadean. The other ancien rocks (>3.8 Ga) are preserved in Antarctica, Canada, China, Greenland, Labrador, Western Australia and Swaziland, with the oldest known rochi on Earth from the Acasta gneiss in Northern Canada, dated at 4.03 Ga. Most likely, the second oldest rock record in the world (>3.9 Ga) may be derivedfrom the Nanok gneiss in the Nain Complex of the Saglek-Hebron area in the northern part of the Labrador Peninsula. Extensive investigation of these rocks will allowfurther characterizing the nature of the earliest preserved crust.

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Wpływ zmian temperatury wody na Prądzie Zachodniogrenlandzkim na zmiany temperatury powietrza na Ziemi Baffina i Labradorze (1982-2002)

Zblewski S.

Problemy Klimatologii Polarnej

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2005

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nr 15

41-51

PL

Praca omawia wpływ zmian temperatury wody powierzchniowej (TPO) w południowej i środkowej części Prądu Zachodniogrenlandzkiego na zmiany temperatury powietrza na stacjach położonych na wschodnich wybrzeżach Kanady. Szeregi temperatury powietrza pochodzą ze zbioru Historical Adjusted Climate Database for Kanada, a dane o TPO ze zbioru Reynoldsa w wersji SST OI v.1. W okresie 1982-2002 na wszystkich analizowanych stacjach występują dodatnie, istotne statystycznie trendy temperatury powietrza. Pomiędzy szeregami TPO w wybranych gridach ([62°N, 52°W] i [66°N, 56°W]) a szeregami temperatury powietrza na badanych stacjach dominują związki synchroniczne. Najsilniejsze związki asynchroniczne zachodzą pomiędzy zmiennością TPO w środkowej części Prądu Zachodniogrenlandzkiego a temperaturą powietrza na stacjach położonych na Ziemi Baffina.

EN

This work deals the influence of changes the sea surface temperature (SST) in south and the centre part of the West Greenland Current in relays of the air temperature (AT) on stations located on eastern sea-coasts of Canada (Fig.1). The West Greenland Current is a warm current, which transports warm waters to the bay/ gulf of the Baffin Sea and in this way has a great influence on the formation of ice cover and on air temperature in this area. The Reynolds?s data set, version SST OI v.1., covering values of mean monthly SST in grids 1°x1° has been used as the data source. Yearly temperatures for selected grids have been calculated on the basis of mean monthly temperatures. Series of the air temperature for selected Canadian stations proceed from the service HCCD (Historical Adjusted Climate Database for Canada). The period 1982-2002 is characterized with the distinct warming up of the climate on the northern hemisphere. Appears this i.a. an increase in air temperature and an advanced process of sea ice cover degradation. A reason of this warming up is the accumulation of the warm in surface layers of the ocean and his distribution by the oceanic circulation. Trends in chronological series of mean yearly values of AT on stations located along of eastern sea-coasts of Canada have been analysed. Such an analysis indicated that on all staion the trends in air temperature prove to be positive and that these trends are statistically relevant (p < 0.05 ) on all stations. The highest values of trends can be observed on stations in the central and southern part of Baffin Island. Courses of the one year's temperature of air on selected stations show almost in step reaching changes (Fig. 2). Passed correlational analysis showed that among investigated series SST in selected grids ([62°N, 52°W] and [66°N, 56°W]) located on the West Greenland Current and series AT on stations situated on eastern sea-coasts of Canada dominated synchronous relationships. With the example can be the relationship among SST in grid [66°N, 56°W] and AT on the station Cape Dyer, where appear high values of coefficients of correlation and the maximum of the power of the relationship fall on December +0.93 (Tab. 1). Research showed that the variability of the yearly sea surface temperature in grid [66°N, 56°W] indeed influence on the formation of yearly AT on selected stations. On the stations Cape Dyer and Iqaluit the variability of yearly SST explains the variability of yearly AT properly into 67 and 57% (Fig. 3). On the warm West Greenland Current the changes of the water temperature outdistance during changes of the air temperature on stations of eastern sea-coasts of Canada. Such asynchronous relationships are best visible among a June and May sea surface temperature in grid [66°N, 56°W] and yearly AT on stations located in the Northern part of Baffin Island - Fig.4 and among May SST in grid [66°N, 56°W] and yearly AT in the next year (Fig.5). Most strong synchronous and asynchronous relationships between the variability of the sea surface temperature in the central part of the West Greenland Current and the air temperature occur on stations located on the Baffin Island area.