Late Quaternary sedimentation on the southwestern Scotian Slope, eastern Canada: relationship to glaciationGeological Survey of Canada Contribution 20070176.

2008 ◽  
Vol 45 (3) ◽  
pp. 267-285 ◽  
Author(s):  
Thian Hundert ◽  
David J.W. Piper
Keyword(s):  
Late Quaternary ◽  
Sediment Cores ◽  
Sediment Supply ◽  
Scotian Shelf ◽  
Eastern Canada ◽  
Glacial Retreat ◽  
Air Gun ◽  
Continental Slopes ◽  
History Of ◽  
Seismic Reflection Profiles

The sedimentary record on continental slopes has the potential to preserve a record of glacial retreat on the adjacent continental shelf. The glacial history of the southwestern part of the Scotian Shelf is poorly known. Air-gun and high-resolution sparker profiles and numerous sediment cores up to 10 m long have been used to determine the character of sedimentation on the southwestern Scotian Slope since the last glacial maximum (LGM). Seismic-reflection profiles show that glacial till was deposited at shallow depths on the upper continental slope, and correlation to dated piston cores farther downslope show that this till dates from the LGM. Slope sedimentation at this time was dominated by local ice and deposited as plume fallout and turbidites. Progressively increasing importance of red-brown sediment derived from glacial supply to Laurentian Channel indicates retreat of ice from the shelf edge and diminishing supply of proglacial sediment from the calving embayment in the mid-Scotian Shelf. With the termination of distal proglacial sediment supply, the sedimentation rate diminished rapidly and hemipelagic sedimentation prevailed through the Holocene.

Late Quaternary Water-Level Variations and Vegetation History at Crooked Pond, Southeastern Massachusetts

2001 ◽  
Vol 56 (3) ◽  
pp. 401-410 ◽  
Author(s):  
Bryan Shuman ◽  
Jennifer Bravo ◽  
Jonathan Kaye ◽  
Jason A. Lynch ◽  
Paige Newby ◽  
...  
Keyword(s):  
New England ◽  
Water Level ◽  
Vegetation History ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Climatic Conditions ◽  
Water Levels ◽  
Eastern Canada ◽  
Southern New England ◽  
Dramatic Rise

AbstractSediment cores collected along a transect in Crooked Pond, southeastern Massachusetts, provide evidence of water-level changes between 15,000 cal yr B.P. and present. The extent of fine-grained, detrital, organic accumulation in the basin, inferred from sediment and pollen stratigraphies, varied over time and indicates low water levels between 11,200 and 8000 cal yr B.P. and from ca. 5300 to 3200 cal yr B.P. This history is consistent with the paleohydrology records from nearby Makepeace Cedar Swamp and other sites from New England and eastern Canada and with temporal patterns of regional changes in effective soil moisture inferred from pollen data. The similarities among these records indicate that (1) regional conditions were drier than today when white pine (Pinus strobus) grew abundantly in southern New England (11,200 to 9500 cal yr B.P.); (2) higher moisture levels existed between 8000 and 5500 cal yr B.P., possibly caused by increased meridonal circulation as the influence of the Laurentide ice sheet waned; and (3) drier conditions possibly contributed to the regional decline in hemlock (Tsuga) abundances at 5300 cal yr B.P. Although sea-level rise may have been an influence, moist climatic conditions during the late Holocene were the primary reason for a dramatic rise in water-table elevations.

Late Quaternary sedimentation in Baffin Bay

1987 ◽  
Vol 24 (9) ◽  
pp. 1833-1846 ◽  
Author(s):  
A. E. Aksu ◽  
David J. W. Piper
Keyword(s):  
Debris Flow ◽  
Late Quaternary ◽  
Ocean Basin ◽  
The Arctic ◽  
Bottom Current ◽  
Eastern Canada ◽  
Baffin Bay ◽  
Quaternary Glaciation ◽  
Continental Slopes ◽  
Channel Systems

Baffin Bay is a small ocean basin that connects the Arctic and Atlantic oceans. The adjacent continental shelves have been extensively reworked during Quaternary glaciation. The shelf break generally lies between 200 and 500 m. The continental slope passes directly into the abyssal plain of Baffin Bay basin without any major submarine canyon – deep-sea fan system being present, except for a large smooth sediment apron in northern Baffin Bay.On the basis of over 50 piston cores, six Quaternary sediment facies are distinguished from detrital mineralogy (reflected in colour) and sediment texture. Facies A, B, and C are predominantly ice-rafted or are debris flow deposits, each with a distinct mineralogy. Facies D is turbidites and bottom-current sorted sands, silts, and muds. Facies E is hemipelagic sediment. Facies F consists of sediments ranging from slumps, through debris flow deposits, to fine-grained turbidites, with a distinctive provenance in northern Baffin Bay.These sediment facies appear to be partly controlled by glacial conditions. Hemipelagic facies E predominates during the present interglacial. During glacial stages, facies D turbidites were deposited. They resulted from slumping of proglacial sediments on the continental slopes off Greenland and Baffin Island. Facies C and F occurred on the continental slopes at these times. Ice-rafted facies A and B predominate at several horizons, reflecting a rapid breakup of ice shelves in northern Baffin Bay and increased rates of iceberg melting within the Bay. Overall sedimentation rates are relatively low, reflecting dry-base ice sheets in source areas.Deep-sea channel systems floored by sorted coarse sediments and bounded by muddy levees are absent in Baffin Bay, in contrast to mid-latitude glaciated continental margins off eastern Canada. These channel systems are the result of melting of wet-base glaciers, which provide a localized supply of sediment that is sorted by ice margin processes. In Baffin Bay, most glacial sediments are derived by calving of icebergs, probably from dry-base glaciers. Sediments are gradually released over large areas as the bergs melt, and are subsequently redistributed by debris flows.

scholarly journals Late-Quaternary Vegetational and Climatic History of the Yellowstone/Grand Teton Region

1988 ◽  
Vol 12 ◽  
pp. 189-192
Author(s):  
Cathy Barnosky
Keyword(s):  
Environmental History ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Sediment Accumulation ◽  
Fire Frequency ◽  
Ice Age ◽  
Sediment Chemistry ◽  
History Of ◽  
Climatic History

The research underway has focused on two different aspects of the environmental history of the Yellowstone/Grand Teton region. One objective has been to examine the long-term vegetational and climatic history of Jackson Hole, the Pinyon Peak Highlands, and Yellowstone Park since the end of late Pinedale glaciation, about 14,000 years ago. Fossil pollen in sediment cores from lakes in the region is being analyzed to clarify the nature and composition of ice-age refugia, the rate and direction of plant migrations in the initial stages of reforestation, and the long-term stability of postglacial communities. Sedimentary charcoal also is being examined to reconstruct fire frequency during different climatic regions and different vegetation types in the past. This information is necessary to assess the sensitivity of plant communities to environmental change and to understand postglacial landscapes of the northern rocky Mountains. The second objective has been a multidisciplinary investigation of the relationship of climate to sedimentation rates in lakes and ponds in Yellowstone, undertaken with Drs. Wright, D.R. Engstrom and S.C. Fritz of the University of Minnesota. This facet of the research examines the relative importance of climate, fire, hillslope erosion induced by overgrazing, and nutrient enrichment in the last 150 years, as recorded in selected lakes in the northern range of Yellowstone. Populations of elk and bison are known to have fluctuated greatly during this interval, and slight climatic changes are suggested from other lines of research. In this study pollen, diatoms, charcoal, sediment chemistry, and sediment accumulation rates are analyzed in short cores from small lakes.

Late Quaternary History of Lake Manitoba, Canada

1981 ◽  
Vol 16 (1) ◽  
pp. 97-116 ◽  
Author(s):  
James T. Teller ◽  
William M. Last
Keyword(s):  
Late Quaternary ◽  
Sediment Cores ◽  
Water Levels ◽  
The South ◽  
Lake Agassiz ◽  
Barrier Beach ◽  
South Basin ◽  
Lithostratigraphic Units ◽  
Dry Conditions ◽  
History Of

AbstractThe postglacial history of Lake Manitoba has been deduced from a study of the changes in physical, mineralogical, and chemical variables in sediment cores collected from the lake. Six lithostratigraphic units are recognized in the South Basin of the lake. Weakly developed pedogenic zones, reflecting dry or extremely low water conditions in the basin, separate five of these six units. The initial phase of lacustrine sedimentation in the Lake Manitoba basin began shortly after 12,000 yr B.P. as water was impounded in front of the receding glacier to form Lake Agassiz. By 11,000 yr ago, continued retreat of the ice sheet opened lower outlets to the east and much of Lake Agassiz drained, including the Lake Manitoba basin. Water levels again rose at 9900 yr B.P., but by about 9200 yr B.P. the South Basin was again dry. For the next 4700 yr there was an alternation of wet and dry conditions in the basin in response to the interaction of a warmer and drier climate and differential crustal rebound of the basin. About 4500 yr ago a new phase of Lake Manitoba sedimentation was initiated when the Assiniboine River began to discharge into the South Basin. The Assiniboine River was diverted out of the Lake Manitoba watershed about 2200 yr ago. Erosion and redistribution of the sandy deltaic sediments deposited by the Assiniboine River has created the barrier beach that now separates the extensive marsh to the south of the lake from the main lake.

Late Quaternary glacial history and meltwater discharges along the Northeastern Newfoundland Shelf

2013 ◽  
Vol 50 (12) ◽  
pp. 1178-1194 ◽  
Author(s):  
Jonathan Roger ◽  
Francky Saint-Ange ◽  
Patrick Lajeunesse ◽  
Mathieu J. Duchesne ◽  
Guillaume St-Onge
Keyword(s):  
Late Quaternary ◽  
Sediment Cores ◽  
Water Environment ◽  
Open Water ◽  
Laurentide Ice Sheet ◽  
Glacial Processes ◽  
Trough Mouth Fans ◽  
Seismic Reflection Profiles ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The geomorphology of the Eastern Canadian margin has been shaped by glacial processes during the Quaternary. Many studies have focused on the ice-sediment pathway through Hudson Strait to reconstruct the dynamics of the Laurentide Ice Sheet, and as a consequence, little is known on its marginal ice domes. Here we reconstruct the dynamics of two trough mouth fans (TMFs) offshore NE Newfoundland using sediment cores and radiocarbon ages supported by very high resolution seismic reflection profiles. These two TMFs, namely Notre Dame and Hawke, are fed by two glacial troughs incised in the bedrock. The TMFs show a complete sedimentary sequence from 30 ka BP to the beginning of the Holocene. The sampled sedimentary record on the upper slope extends back to a thick Heinrich event 3 (H3) deposit that corresponds to the end of the maximum extent of the Newfoundland ice dome. Above H3, a thick succession of turbidite deposits (>10 m) observed in both TMFs is correlated with periods of major meltwater supply from 28–29 to 17 ka BP. Our results show that the Last Glacial Maximum (LGM) period was characterized by major input of meltwater events stemming from the Newfoundland dome. The presence of H1 (∼17 ka BP) coincide with the end of the turbidite activity which is replaced by an open-water environment characterized by hemipelagic sediments rich in ice-rafted debris. The proglacial muddy sediment older than 13.3 ka BP on the shelf shows that ice was not grounded after H1, suggesting a very rapid retreat of the ice on the Newfoundland shelf after 17 ka BP.

Late Quaternary history of contourite drifts and variations in Labrador Current flow, Flemish Pass, offshore eastern Canada

2014 ◽  
Vol 34 (5) ◽  
pp. 457-470 ◽  
Author(s):  
Nicole R. Marshall ◽  
David J. W. Piper ◽  
Francky Saint-Ange ◽  
D. Calvin Campbell
Keyword(s):  
Current Flow ◽  
Late Quaternary ◽  
Eastern Canada ◽  
Contourite Drifts ◽  
Labrador Current ◽  
History Of ◽  
Quaternary History

scholarly journals Late-Quaternary Vegetation History of Jackson Hole, Wyoming

1982 ◽  
Vol 6 ◽  
pp. 35-36
Author(s):  
Cathy Barnosky
Keyword(s):  
Environmental History ◽  
Plant Communities ◽  
Rocky Mountains ◽  
Vegetation History ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Northern Rocky Mountains ◽  
Hole Area ◽  
Jackson Hole ◽  
History Of

During the late Quaternary, the Jackson Hole area has reen repeatedly glaciated-the most recent and least extensive ice advance occurred during the Pinedale Glaciation (ca. 25,000-9,000 yr B.P.; Love and Reed, 1971). The objective of this research is to study the vegetation history of Jackson Hole since Pinedale time, as a means of interpreting the development and stability of modern plant communities. The research is based on an examination of pollen and plant-macrofossiil records contained in lake-sediment cores collected near the former ice margin. The environmental history of this region is poorly known and the paleoecological information provided by this study should help fill a gap in our understanding of the vegetation, climate, and glacial history of the Northern Rocky Mountains.

scholarly journals Etude de l'impact des barrages sur la réduction des transports sédimentaires jusqu'à la mer par approche paléohydrologique dans la basse vallée de la Medjerda

2018 ◽  
Vol 377 ◽  
pp. 67-76 ◽  
Author(s):  
Fatma Kotti ◽  
Laurent Dezileau ◽  
Gil Mahé ◽  
Hamadi Habaieb ◽  
Malik Bentkaya ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Global Climate ◽  
Sediment Cores ◽  
Sediment Supply ◽  
Water Storage Capacity ◽  
Sedimentary Deposits ◽  
The Core ◽  
River Bed ◽  
History Of ◽  
Marine Influence

Abstract. The sedimentary contributions of the Medjerda to the coastal zone are poorly measured, and there is no chronicle of observations. In this context, the sediment monitoring appears indispensable for the quantification of sediment transport at the outlet. This study focuses on the largest watershed in Tunisia, the Wadi Medjerda (23 600 km2). The main objective of this work is to assess the reduction of sediment transport following anthropogenic intensification on the basin, especially since the construction of many large dams. In order to collect information on actual deposits over several years, the paleo-hydrological approach was applied through the study of sediment cores sampled in the low valley meanders on alluvial terraces, after the last dam (Sidi Salem, the largest water storage capacity over the basin), but before the estuary to avoid marine influence and near a hydrological station (Jdaida). The sedimentary deposits of the river provide key information on the past sedimentary inputs. A visible succession of sedimentary layers corresponding to the deposits of successive floods on the study site has been determined and the history of the sedimentary contributions of the Medjerda is reconstructed by this approach. The thickest layers of sedimentary deposits are related to exceptional events. They are mainly concentrated on the lower part of the core and are mainly composed of sands. The first 1.2 m of the core from the bottom upward relates to 10 years of river discharges, as can be determined from the 137Cs datation. The next upward 1.05 m of core relates to the following 20 years of discharges, up to 1981, date of the construction of the Sidi Salem dam, and is composed of a mix of sand, silts and clays. The last 75 cm of core near the surface is only composed of clays with thin silt bands, and relates to a period of 32 years. We thus observe that there is no more sand deposits in the river bed since the construction of the Sidi Salem dam. The deficit of sediment supply to the sea is viewed as a major factor to be taken into account for better understanding of the dynamics of coastal areas in the context of global climate change.

scholarly journals Late Quaternary history of Lammefjorden, north-west Sjælland, Denmark

2020 ◽  
Author(s):  
Ole Bennike ◽  
Peter Roll Jakobsen ◽  
Jakob Walløe Hansen
Keyword(s):  
Late Quaternary ◽  
Sediment Cores ◽  
Late Glacial ◽  
Early Holocene ◽  
Last Deglaciation ◽  
North West ◽  
Najas Marina ◽  
Marine Deposits ◽  
Minimum Age ◽  
History Of

Lammefjorden is a reclaimed fjord in north-west Sjælland, Denmark. Sediment cores from the area were collected to study its development after the last deglaciation, in particular the sea-level history. Late glacial and Early Holocene lake and bog deposits occur below marine deposits. Sparse late glacial fossil assemblages indicate tree-less environments with dwarf-shrub heaths. Early Holocene deposits contain remains of Betula sec. Albae sp. and Pinus sylvestris, which indicate open forests. The wetland flora comprised the calciphilous reed plant Cladium mariscus and the water plant Najas marina. Marine gyttja from basins is characterised by sparse benthic faunas, probably due to high sedimentation rates. In some areas, shell-rich deposits were found, with large shells of Ostrea edulis, indicative of high summer temperatures, high salinity and strong tidal currents. A marine shell dated to 6.7 cal. ka provides a minimum age for the marine transgression of Lammefjorden.

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