The last glaciation of Marvin Peninsula, northern Ellesmere Island, High Arctic, Canada

1989 ◽  
Vol 26 (12) ◽  
pp. 2578-2590 ◽  
Author(s):  
Donald S. Lemmen
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
North Coast ◽  
Radiocarbon Dates ◽  
The North ◽  
Last Glaciation ◽  
Ice Retreat ◽  
Late Wisconsinan ◽  
Glaciomarine Sediments ◽  
North And South

The limit of the last glaciation on Marvin Peninsula, northernmost Ellesmere Island, is recorded by extensive ice-marginal landforms and early Holocene glaciomarine sediments. While glaciers occupied most valleys on the peninsula, other areas remained ice free, as did most of the adjacent fiords. Beyond the ice limit, sparse erratics and degraded meltwater channels within weathered bedrock are evidence of older, more extensive glaciation(s). Shorelines and marine shells 50 m above the limit of the Holocene sea along the north coast relate to these older glacial events.Thirty-four new radiocarbon dates provide a chronology of ice buildup and retreat. Glaciers reached their limit after 23 ka, and locally as late as 11 ka. This was achieved by both expansion of existing glaciers and accumulation on plateau and lowland sites, which are presently ice free. Late Wisconsinan climate was characterized by cold and extreme aridity. Five dates ranging from 11 to 31 ka BP on subfossil bryophytes suggest that ice-free areas were biologically productive throughout the last glaciation. Ice retreat and postglacial emergence had begun by 9.5 ka and was associated with a marked climatic amelioration. The deglacial chronology confirms a pronounced disparity in the timing of ice retreat on the north and south sides of the Grant Land Mountains.

scholarly journals Snowfall and Oxygen-Isotope Variations off the North Coast of Ellesmere Island, N.W.T., Canada

1987 ◽  
Vol 33 (114) ◽  
pp. 195-199 ◽  
Author(s):  
Martin O. Jeffries ◽  
H. Roy Krouse
Keyword(s):  
Arctic Ocean ◽  
High Arctic ◽  
Geographic Region ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Snow Pack ◽  
The North ◽  
Winter Snow ◽  
The Mean

AbstractSnow-pack along the land-fast ice fringe off the north coast of Ellesmere Island was generally characterized by depth-hoar overlain by dense snow and wind slab. Mean snow depth in the study area was 0.54 m (1982-85) and the mean δ18O value of the snow-pack was -31.3˚/00. Isotope data were not obtained previously for this geographic region and, therefore, complement a previous study of δ18O variations in High Arctic snow (Koerner, 1979). The data are consistent with an Arctic Ocean moisture source. The δ18O profiles show seasonal variations, with winter snow being more depleted in 18O than fall and spring snow. However, the δ18O profiles are dominated by a trend to higher δ18O values with increasing depth. This is attributed to a decrease in δ18O values as condensation temperatures fall during the autumn-winter accumulation period. During this time, there is also a change from relatively open to almost complete ice cover in the Arctic Ocean. The change in evaporation conditions and consequent effect on δ values gives rise to a sharp discontinuity in the δ18O profiles and a bi-modal δ18O frequency distribution. The bi-modal distribution is reinforced by a secondary isotope fractionation that occurs during depth-hoar formation. This isotope effect leads to a wider δ18O range but does not significantly alter the mean δ18O value.

scholarly journals Snowfall and Oxygen-Isotope Variations off the North Coast of Ellesmere Island, N.W.T., Canada

1987 ◽  
Vol 33 (114) ◽  
pp. 195-199 ◽  
Author(s):  
Martin O. Jeffries ◽  
H. Roy Krouse
Keyword(s):  
Arctic Ocean ◽  
High Arctic ◽  
Geographic Region ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Snow Pack ◽  
The North ◽  
Winter Snow ◽  
The Mean

AbstractSnow-pack along the land-fast ice fringe off the north coast of Ellesmere Island was generally characterized by depth-hoar overlain by dense snow and wind slab. Mean snow depth in the study area was 0.54 m (1982-85) and the mean δ18O value of the snow-pack was -31.3˚/00. Isotope data were not obtained previously for this geographic region and, therefore, complement a previous study of δ18O variations in High Arctic snow (Koerner, 1979). The data are consistent with an Arctic Ocean moisture source. The δ18O profiles show seasonal variations, with winter snow being more depleted in18O than fall and spring snow. However, the δ18O profiles are dominated by a trend to higher δ18O values with increasing depth. This is attributed to a decrease in δ18O values as condensation temperatures fall during the autumn-winter accumulation period. During this time, there is also a change from relatively open to almost complete ice cover in the Arctic Ocean. The change in evaporation conditions and consequent effect on δ values gives rise to a sharp discontinuity in the δ18O profiles and a bi-modal δ18O frequency distribution. The bi-modal distribution is reinforced by a secondary isotope fractionation that occurs during depth-hoar formation. This isotope effect leads to a wider δ18O range but does not significantly alter the mean δ18O value.

NOTES ON NEARCTIC HEPATICAE XVIII NEW LOPHOZIACEAE FROM THE ARCTIC ARCHIPELAGO OF CANADA

1961 ◽  
Vol 39 (4) ◽  
pp. 965-992 ◽  
Author(s):  
Rudolf M. Schuster
Keyword(s):  
American Literature ◽  
High Arctic ◽  
Living Condition ◽  
Western Hemisphere ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Widespread Distribution ◽  
The North ◽  
Difficult Genus

The difficult genus Lophozia, of widespread distribution in the cooler and cold regions of the northern hemisphere, includes a high number of technical species, some of which are very poorly understood. During the summer of 1955 the writer collected extensively on the north coast of Ellesmere Island and was able to study, in the living condition, the high-arctic representatives of this genus. Four species not previously found in the Arctic Archipelago of Canada, three of which are new to the western hemisphere, were collected. Two of these, L. groenlandica and L. opacifolia, are first reported from the Canadian Archipelago in this paper. Two others, L. pellucida and L. hyperarctica, appear to be new to science. These belong to the subgenera Lophozia and Massula, respectively. Since these species are not alluded to in my "Conspectus" of 1951, and since no treatment of them exists in the American literature, the following detailed treatment is provided.

Geochronology and Settlement Disposition in the Early Palaeo-Indian Occupation of Southern Ontario, Canada

1983 ◽  
Vol 19 (3) ◽  
pp. 388-399 ◽  
Author(s):  
L. J. Jackson
Keyword(s):  
Main Stage ◽  
Radiocarbon Dates ◽  
Southern Ontario ◽  
The North ◽  
Lake Algonquin ◽  
Ice Retreat ◽  
Major River ◽  
Late Wisconsinan ◽  
Edge Features ◽  
River Valleys

AbstractExamination of a sample of 150 fluted-point localities from southern Ontario, Canada in relation to datable features of Late Wisconsinan ice retreat discloses maximum possible ages for early Palaeo-Indian occupation and reveals selection of specific physiographic situations. General relationship to maximum ice-advance positions suggests occupation during the Two Creeks Interstade after Port Huron ice retreat about 12,300 yr B.P. Specific relationship to 14C-dated proglacial Great Lake strands favors occupation during the North Bay Interstade after Greatlakean ice retreat about 11,500 yr B.P. Locality frequency on Lake Algonquin strands suggests contemporaneity with the main stage of this lake about 11,500 to 10,400 yr B.P., with a small number of lake-plain localities indicating minor post-Algonquin persistence. Radiocarbon dates for fluted-point sites elsewhere in the glaciated northeast place occupation coeval with the southwestern Folsom fluted-point tradition of about 10,850 to 10,200 yr B.P. Locality situation in regions dominated by proglacial sediments, on lake-edge features adjacent to strand-dissecting tributaries, within major river valleys, implies selectivity reflecting primary adaptation. Fluted-point associations with caribou and elk remains suggest that “focal” adaptation to cervids, comparable to southwestern Folsom bison exploitation, might underlie the homogeneous nature and distribution of early Palaeo-Indian localities throughout the northeast.

The last glaciation and sea level history of Fosheim Peninsula, Ellesmere Island, Canadian High Arctic

1996 ◽  
Vol 33 (7) ◽  
pp. 1075-1086 ◽  
Author(s):  
Trevor Bell
Keyword(s):  
High Arctic ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Ice Caps ◽  
Marine Deposits ◽  
Last Glaciation ◽  
Maximum Elevation ◽  
Glacier Runoff ◽  
History Of ◽  
Ice Conditions

The last glaciation of Fosheim Peninsula is reconstructed on the basis of landform and sediment mapping and associated radiocarbon dates. Ice growth involved the expansion of cirque glaciers and accumulation on upland surfaces that are now ice free. Limited ice buildup, despite lowering of the paleoglaciation level by 700–800 m, is attributed to the hyperaridity of the region during glacial conditions. Marine deposits in formerly submerged basins beyond the ice margins are interpreted to represent (i) sedimentation caused by local ice buildup and marine transgression by 10.6 ka BP, (ii) increased ablation and glacier runoff [Formula: see text]9.5 ka BP, and (iii) marine regression during the Holocene. Holocene marine limit reaches a maximum elevation of approximately 150 m asl along northern Eureka Sound and Greely Fiord and descends southeastwards to 139–142 m asl near the Sawtooth Mountains. A synchronous marine limit is implied where the last ice limit was inland of the sea. The magnitude and pattern of Holocene emergence cannot be fully explained by the glacioisostatic effects of the small ice load during the last glaciation of the region. Deglaciation of the peninsula was underway by 9.5 ka BP; however, local ice caps may have persisted through the wannest period of the Holocene until 6–5 ka BP. This was likely a function of reduced sea ice conditions and increased moisture availability which benefited low-lying coastal icefields, but had negligible effect on interior highland ice caps.

The glacial geology of northeastern Ellesmere Island, N.W.T., Canada

1978 ◽  
Vol 15 (4) ◽  
pp. 603-617 ◽  
Author(s):  
John England
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ellesmere Island ◽  
Glacial Geology ◽  
Radiocarbon Dates ◽  
Previous Evidence ◽  
Marine Deposits ◽  
Last Glaciation ◽  
Distal Side ◽  
Stratigraphic Boundary

Thirty-five radiocarbon dates associated with former ice sheet margins and raised marine deposits are presented from northeastern Ellesmere Island. Along the southern margin of Hazen Plateau, and in inner Archer Fiord, a prominent morpho-stratigraphic boundary is marked by the Hazen Moraines. These moraines represent a restricted ice advance during the last glaciation and date ca. 8130 ± 200 BP. On the immediate distal side of the Hazen Moraines, eastward for 100 km towards northwestern Greenland, the majority of dates on marine limits show synchronous emergence beginning ca. 7500 BP. This zone of synchronous emergence is considered to represent an ice-free corridor isostatically unloaded between the margins of the receding Greenland and Ellesmere island ice sheets.A more widespread till, above and beyond the Hazen Moraines, extends out of Archer Fiord–Lady Franklin Bay to Robeson and Kennedy channels. This maximum ice advance is considered to predate the last glaciation on the basis of 14C and amino acid dates from ice-marginal deposits; however, alternative interpretations of the data are presented. Previous evidence suggesting an older advance of the Greenland Ice Sheet onto this coastline is confirmed. Several glaciers in the area are presently at their maximum postglacial positions.

A reconstruction of glacial events in southeastern New Brunswick

1991 ◽  
Vol 28 (10) ◽  
pp. 1594-1612 ◽  
Author(s):  
Marc Foisy ◽  
Gilbert Prichonnet
Keyword(s):  
New Brunswick ◽  
Ice Flow ◽  
Ice Cap ◽  
The North ◽  
Lithostratigraphic Units ◽  
Glaciofluvial Deposits ◽  
Southern Border ◽  
Late Wisconsinan ◽  
Radial Outflow ◽  
North And South

Sedimentological and petrographical data obtained from five sections located north and south of the Caledonian Highlands in southeastern New Brunswick demonstrate the existence of three main till units and one glaciofluvial unit, which have been grouped in four distinct lithostratigraphic units. The lower till was deposited by a glacier that overrode the Caledonian Highlands from northwest to southeast and advanced as far as Nova Scotia during Middle(?) to Late Wisconsinan times. The overlying middle till from the north provides evidence that ice continued to advance across the Highlands from northwest toward southeast and then was partially overwhelmed by another glacier that was advancing southwest along the southern border of the Highlands: this glacier deposited a coeval middle till. During Late Wisconsinan deglaciation, ice separated into two masses: a residual ice cap with radial outflow from the Highlands; and a lobe in the Chignecto Bay, retreating toward the northeast. The existence of a plateau ice cap is demonstrated by the presence of till and glaciofluvial deposits in the upper part of all surveyed sections, and is supported by the sequence of ice flow patterns recorded by striae and the centrifugal distribution of meltwater flow indicators. The weak development of soils, the fresh appearance of till and morainic landforms, and the lack of periglacial features throughout the area, especially on the Highlands, all favour the interpretation that the Caledonian Highlands were not a nunatak during the glacial maximum of the Late Wisconsinan Substage.

Glacial geology and Quaternary marine stratigraphy of the Robeson Channel area, northeastern Ellesmere Island, Northwest Territories

1986 ◽  
Vol 23 (7) ◽  
pp. 1001-1012 ◽  
Author(s):  
Michael J. Retelle
Keyword(s):  
Greenland Ice Sheet ◽  
Free Fraction ◽  
High Arctic ◽  
Ellesmere Island ◽  
Major Advance ◽  
Total Acid ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Acid Hydrolysate ◽  
Field Area

Glacial and marine deposits associated with two phases of glaciation are exposed along a 60 km corridor on Ellesmere Island that borders Robeson Channel. The oldest sediments, tentatively dated at ≥ 70 000 BP, were deposited during a major advance of the northwest Greenland ice sheet across Robeson Channel. During subsequent retreat of this ice mass, glaciomarine sediments containing a High Arctic macro- and microfauna were deposited in the isostatic downwarp on Ellesmere Island. This marine unit was radiocarbon dated at 31 300 ± 900 and > 32 000 BP; mean aIle/Ile ratios are 0.218 ± 0.03 for the free fraction and 0.063 ± 0.011 for the total acid hydrolysate.The last ice advance (late Wisconsin – early Holocene) did not extend into the field area from either interior Ellesmere Island or northwest Greenland. The ice-marginal sea transgressed to the marine limit (~116 m) and overlapped the deposits of the previous maximum Greenland advance. Local plateau ice caps did, however, spill over into one major valley and delayed the establishment of the marine limit in this location. Radiocarbon dates on the Holocene marine limit shorelines indicate initial emergence between 8000 and 8600 BP. A mean aIle/Ile ratio of 0.037 was found for the total acid hydrolysate; aIle was undetectable in the free fraction of the Holocene shells.The Holocene and pre-Holocene glacial and marine chronologies in the Robeson Channel area are similar to chronologies demonstrated from other locations in Arctic regions. Tentative correlations based upon aminostratigraphy suggest that the field area has remained, for the most part, ice free since at least 70 000 BP.

scholarly journals Diversity and distribution of microalgae in coastal areas of East Java, Indonesia

2020 ◽  
Vol 21 (3) ◽  
Author(s):  
UMI ZAKIYAH ◽  
MULYANTO ◽  
LUCIA TRI SUWANTI ◽  
MOCHAMAD DONNY KOERNIAWAN ◽  
EKO AGUS SUYONO ◽  
...  
Keyword(s):  
Human Activities ◽  
Diversity Index ◽  
Renewable Energy Sources ◽  
Biodiversity Loss ◽  
Coastal Areas ◽  
South Coast ◽  
North Coast ◽  
The North ◽  
Anthropogenic Development ◽  
North And South

Abstract. Zakiyah U, Mulyanto, Suwanti LT, Koerniawan MD, Suyono EA, Budiman A, Siregar UJ. 2020. Diversity and distribution of microalgae in coastal areas of East Java, Indonesia. Biodiversitas 21: 1149-1159. Indonesia is well known as one of hotspot for biodiversity, including marine resources. However, Indonesia biodiversity has declined rapidly due to the changes in the aquatic environmental quality as the consequence of human activities. Biodiversity loss has been well studied in larger organisms, however, less is known for microorganisms, such as microalgae. Microalgae have received much attention recently due to its potential as renewable energy sources. This study aimed at describing biodiversity and distribution of microalgae in coastal areas of East Java and Madura, Indonesia. Six sites, i.e. Trenggalek and Sendangbiru representing south coast, Banyuwangi and Situbondo representing north coast of East Java, Pasongsongan and Pamekasan representing Madura north and south coast, respectively were sampled, which representing different background of anthropogenic development in these areas. Results showed that seawater condition in all sites is still good, with average pH 8.0 despite intense human activities, such as ecotourism, fishing and boat harbor, as well as residential area that has the potential to produce a lot of waste. Totally, there were 35 genera from all locations with varying abundance in each location and diversity index ranging from 1.105-3.312. Although most genera belonged to Bacyllariophyta, domination indices showed that there was not any single specific domination in all locations. Morisita indices showed that most distribution gave positive values indicating clumped dispersion of microalgae in all locations. Higher Shannon-Weaver indices characterized the south coast of East Java and Madura compared to the north coast of East Java area, which corresponded with lower dominancy indices.

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