A sea-level curve for the Canadian Beaufort Shelf

1985 ◽  
Vol 22 (10) ◽  
pp. 1383-1393 ◽  
Author(s):  
Philip R. Hill ◽  
Peta J. Mudie ◽  
Kate Moran ◽  
Steve M. Blasco
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Laurentide Ice Sheet ◽  
Shelf Area ◽  
Mackenzie Delta ◽  
Seismic Profiles ◽  
Acoustic Data ◽  
Basin Subsidence ◽  
Late Wisconsinan ◽  
A Minor

Radiocarbon-dated peat and peaty clay samples from geotechnical boreholes in the Canadian Beaufort continental shelf have been used to reconstruct a late Quaternary relative sea-level (RSL) curve. The samples were carefully selected and evaluated using palynological techniques, to ensure that reasonable age error limits could be given to each sample. The dated samples were then related to the local geological setting, using seismic profiles to determine the environment of deposition. The resulting data show a rise of 140 m in RSL since 27 000 years BP. A minor lowering of RSL at some time between 20 000 and 10 000 years BP is inferred from acoustic data. Contributions from basin subsidence, sediment loading, and consolidation account for 35 m of the total RSL rise. The RSL curve is interpreted in the light of recent models of the isostatic and eustatic responses of the Earth's crust at the Laurentide ice-sheet margin. Ice may have been more extensive during the middle Wisconsinan than previously thought and may have caused the major lowering of sea level in the shelf area. This ice may have advanced to within several hundred kilometres of the Mackenzie Delta – Tuktoyaktuk Peninsula coast. An ice readvance of late Wisconsinan age probably caused a subsequent minor lowering of RSL.

Late Quaternary Evolution of the Northern Aegean Shelf

1989 ◽  
Vol 32 (1) ◽  
pp. 36-50 ◽  
Author(s):  
C. Perissoratis ◽  
D. Mitropoulos
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Shelf Area ◽  
Seismic Profiles ◽  
Fine Grained ◽  
Nestos River ◽  
River Bed ◽  
Ephemeral Lakes ◽  
Evros River ◽  
River Mouths

AbstractA dense network of 3.5 kHz and Uniboom seismic profiles revealed the geological evolution of the Ierissos-Alexandroupolis Shelf area of the northern Aegean during the latest sea-level rise. Near the end of the Pleistocene, ca. 14,000 yr B.P., the sea was at about − 120 m, and almost 5300 km2 of shelf was exposed to subaerial erosion. Two permanet lakes existed in the Ierissos and Kavalla Gulfs, as well as a number of ephemeral lakes scattered throughout the rest of the area. Kavalla Gulf was drained by the Nestos River which joined the Strymon River at the outer Strymonikos Plateau. On the flat Samothraki Plateau were dune fields, marshes, and a number of minor seasonal rivers, while the Evros River flowed east of the plateau. By ca. 13,000 yr B.P. the sea had risen to − 70 m and covered 30% of the previously exposed shelf. The lakes at Ierissos and Strymonikos Gulfs were shallower and the sea approached to within about 5 km of them. Kavalla Gulf and the adjacent eastern Strymonikos Plateau lay 10 m above sea level, while the sea intruded along river mouths at the Samothraki Plateau. During this transgression of the sea river-bed gravels and sands were covered by silts and clays. At the Pleistocene-Holocene transition, ca. 10,500 yr B.P., the sea lay at about − 50 m and in areas of steep slope the coast was close to its present position. At Kavalla Gulf, the sea advanced along the paleochannel of the Nestos River, and the island of Samothraki was separated from the mainland. By ca. 7500 yr B.P. the sea was only 15 m below its present level and the northeastern Aegean shelf assumed nearly its present morphology. The Nestos River changed course to the east and Thassos Island was separated from the mainland. Coarse sediment formed wedges nearshore, whereas fine-grained sediments were distributed widely by current action. In many areas, relict sediments are present.

Late Quaternary sequence stratigraphy of the Mackenzie Delta

1996 ◽  
Vol 33 (7) ◽  
pp. 1053-1074 ◽  
Author(s):  
Philip R Hill
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Sequence Stratigraphy ◽  
Late Quaternary ◽  
Sediment Supply ◽  
Mackenzie Delta ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
Healing Phase ◽  
Late Wisconsinan

The Late Wisconsinan and Holocene sequence stratigraphy of the Mackenzie Delta provides insights into the glacial history of the region. The base of the described succession is a hummocky regional reflector interpreted to be a flooding surface formed immediately after retreat of glacial ice from the Mackenzie Trough. Above this flooding surface, two progradational parasequences are present. The first, assigned to the transgressive systems tract, is correlated with the Tutsieta Lake readvance of the ice sheet at approximately 13 000 BP. A flooding surface forming the upper boundary of this parasequence extends inland to at least Inuvik, developing as a response to glacial retreat and early Holocene relative sea level rise. The second parasequence of Holocene deltaic deposits is assigned to the highstand systems tract and is characterized by progressive progradation of the delta into the Mackenzie Trough to a position seaward of the present delta coastline. A distinct reduction in gradient of the most recent delta clinoforms is consistent with other data suggesting regional transgression and is interpreted to represent the development of a healing-phase wedge. The reasons for this recent transgression are not clear, because relative sea level rise has decreased and sediment supply probably increased over the last 2000 years. Transgression may be related to decreased efficiency of channels, increased trapping of sediments by thermokarst lakes, overspill of the delta across the eastern margin of the valley, and (or) progressively greater exposure to wave action as the delta became less sheltered by the confines of the glacial valley.

Late Tertiary to late Quaternary record in the Mackenzie Mountains, Northwest Territories, Canada: stratigraphy, paleosols, paleomagnetism, and chlorine - 36

1996 ◽  
Vol 33 (6) ◽  
pp. 875-895 ◽  
Author(s):  
A. Duk-Rodkin ◽  
R. W. Barendregt ◽  
C. Tarnocai ◽  
F. M. Phillips
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Climatic Conditions ◽  
Unconsolidated Sediments ◽  
Laurentide Ice Sheet ◽  
Stratigraphic Sequence ◽  
Late Tertiary ◽  
Mackenzie Mountains ◽  
Late Wisconsinan ◽  
Stratigraphic Succession

A stratigraphic sequence of unconsolidated sediments ranging in age from Late Pliocene to Late Pleistocene is recorded in the Canyon Ranges of the Mackenzie Mountains. Three of the sections (Katherine Creek, Little Bear River, and Inlin Brook) expose bedrock and Tertiary gravel overlain by colluvium and a multiple till sequence of montane origin, separated by paleosols and capped by a till of Laurentide origin. The sections are correlated on the basis of lithology, paleosol development, paleomagnetism, and chlorine dating of surface boulder erratics. A formal stratigraphic nomenclature is proposed for the deposits of this region. The sequence of glacial tills separated by paleosols reflects a long record of glacial–interglacial cycles. Soil properties from the oldest paleosol to modern soil show a general decrease in the degree of soil development, suggesting a progressive deterioration of interglacial climatic conditions. A normal–reverse–normal sequence of remanent magnetization was determined within the stratigraphic succession and assigned to the Gauss–Matuyama–Brunhes chrons, respectively. A Gauss age was assigned to the basal colluvium, an early Matuyama age (including Olduvai) to the first two tills, and a Brunhes age to the last three tills. Laurentide deposits are of Late Wisconsinan age and are restricted to the uppermost part of the stratigraphic succession. Chlorine dates for surface boulders place the all-time limit of the Laurentide Ice Sheet at about 30 ka. The Late Wisconsinan Laurentide Ice Sheet was the only continental ice to reach the Mackenzie and Richardson mountains of the northern Cordillera.

Late Quaternary marine sediments at Chalk River, Ontario

1981 ◽  
Vol 18 (8) ◽  
pp. 1261-1267 ◽  
Author(s):  
N. R. Catto ◽  
R. J. Patterson ◽  
W. A. Gorman
Keyword(s):  
Sea Level ◽  
Marine Sediments ◽  
Late Quaternary ◽  
Late Phase ◽  
Water Environment ◽  
Geographic Location ◽  
Ice Retreat ◽  
Brackish Water Environment ◽  
A Minor ◽  
Marine Clays

The occurrence of marine clays and silts in the Chalk River area necessitates a revision of the previously accepted position of the northwestern extent of the Champlain Sea in the Ottawa Valley. The marine origin of these deposits is demonstrated by sedimentological, geochemical, and paleontological criteria. Boron and vanadium concentrations indicate a salinity for this part of the Champlain Sea of from 12 to 16 parts per thousand. Foraminifera present in the clays suggest a shallow brackish water environment. An evaluation of elevations of the marine limit indicates that the sea was present at Chalk River between about 11 300 and 11 100 years BP and thus was a relatively late phase of the Champlain Sea. It appears that ice cover in the area had prevented an earlier inundation by Champlain Sea waters.Till overlying the marine sediments is attributed to a minor readvance starting about 11 000 years ago. The timing and geographic location of this advance strongly indicate a correlation with the St. Narcisse event, well documented to the east of the Ottawa Valley. With the subsequent ice retreat, aeolian and lacustrine and, later, fluvial conditions prevailed, as isostatic recovery had elevated the area above the existing sea level.

Upper Wisconsinan Submarine End Moraines off Cape Ann, Massachusetts

1985 ◽  
Vol 24 (2) ◽  
pp. 187-196 ◽  
Author(s):  
R.N. Oldale
Keyword(s):  
New England ◽  
Sea Level ◽  
Gulf Of Maine ◽  
Silty Clay ◽  
Seismic Profiles ◽  
Late Wisconsinan ◽  
Water Depths

Seismic profiles across the southwest end of Jeffreys Ledge, a bathymetric high north of Cape Ann, Massachusetts, reveal two end moraines. The moraines overlie upper Wisconsinan glacialmarine silty clay and are composed mostly of subaqueous ice-contact deposits and outwash. They were formed below sea level in water depths of as much as 120 m during fluctuations of a calving ice front. The moraines are late Wisconsinan in age and were formed after the Cambridge readvance, about 14,000 yr B.P., and before the Kennebunk readvance, about 13,000 yr B.P. They represent fluctuations of the ice front during overall retreat of Laurentide ice from the Gulf of Maine and New England.

Late Quaternary glacial history of the Hermitage area of southern Newfoundland

1983 ◽  
Vol 20 (3) ◽  
pp. 399-408 ◽  
Author(s):  
D. A. Leckie ◽  
S. B. McCann
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
South Coast ◽  
Glacial History ◽  
The South ◽  
Ice Cap ◽  
Small Complex ◽  
History Of ◽  
Ice Field ◽  
Late Wisconsinan

During late Wisconsinan glaciation, the northern part of the Hermitage area was glaciated by Newfoundland-centred ice and the southern part by a small, complex, upland ice field, broken by nunataks. During deglaciation a lobe of Newfoundland ice dammed a lake at the head of Bay d'Espoir in which a series of small glaciolacustrine deltas were deposited. Valley glaciers from the southern ice cap reached the south coast at several locations, most notably near Harbour Breton, where a large glaciomarine delta was formed during deglaciation when sea level stood 22–24 m above present HWM. Except for three occurrences of till, no deposits were found that can be attributed to glacial events older than late Wisconsinan.

scholarly journals Late Quaternary Relative Sea-Level Change on the West Coast of Newfoundland*

2007 ◽  
Vol 59 (2-3) ◽  
pp. 129-140 ◽  
Author(s):  
Trevor Bell ◽  
Julia Daly ◽  
Martin J. Batterson ◽  
David G.E. Liverman ◽  
John Shaw ◽  
...  
Keyword(s):  
Sea Level ◽  
West Coast ◽  
Late Quaternary ◽  
General Pattern ◽  
Laurentide Ice Sheet ◽  
The West ◽  
Relative Sea Level ◽  
Show Evidence ◽  
Rate Of Emergence ◽  
Harbour Area

Abstract Two revised relative sea-level (RSL) curves are presented for the Port au Choix to Daniel’s Harbour area of the Great Northern Peninsula, northwestern Newfoundland. Both curves are similar, showing continuous emergence of 120-140 m between 14 700 cal BP and present. The half-life of exponential curves fit to the RSL data is 1400 years and the rate of emergence varies from ~2.3 m per century prior to 10 000 cal BP to ~0.13 m per century since 5000 cal BP. The curves fit a general pattern of RSL history along the west coast of Newfoundland, where there is a southward transition from solely emergence to emergence followed by submergence. Isostatic depression curves are generated for four RSL records spanning the west coast. Almost double the crustal depression is recorded to the northwest, reflecting the greater glacioisostatic loading by the Laurentide Ice Sheet over southern Labrador and Québec compared to a smaller loading centre by a regional ice complex over Newfoundland. Only the St. George’s Bay RSL record in the southwest appears to show evidence for a proglacial forebulge, when at 6000 cal BP an isostatic ridge of 4 m amplitude begins to collapse.

Ice-flow patterns and glacial transport in the eastern Hudson Bay region: implications for the late Quaternary dynamics of the Laurentide Ice Sheet

1995 ◽  
Vol 32 (12) ◽  
pp. 2057-2070 ◽  
Author(s):  
Michel Parent ◽  
Serge J. Paradis ◽  
Éric Boisvert
Keyword(s):  
Compositional Data ◽  
Late Quaternary ◽  
Regional Distribution ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Ice Flow ◽  
Flow Phase ◽  
Late Wisconsinan

Recent field surveys in the eastern Hudson Bay region have led to the discovery of regional ice-flow sequences that require a significant reassessment of the late Quaternary dynamics of the Laurentide Ice Sheet. Two regional ice-flow phases can be recognized from till compositional data and from crosscutting relationships observed on striated bedrock surfaces: the oldest is directed toward the northwest and north-northwest, while the youngest is directed toward the west and includes a late-glacial deflection toward the southwest. The wide regional distribution of striae formed during the early northwestward glacial movement together with the recognition of palimpsest glacial dispersal trains associated with this phase suggest that it was a long-lived, time-transgressive regional event. The ensuing glacial movement is a regionally dominant westward ice-flow phase during which several large glacial dispersal trains were formed downglacier from distinctive bedrock sources. The largest of these trains extends westward over a distance of 120 km from Lac à l'Eau Claire to Hudson Bay. Regional glacial transport data as well as glacial and deglacial landforms indicate that this was a long-lived glacial phase, likely lasting throughout the Late Wisconsinan glacial maximum and until déglaciation about 8000 BP. The erosional and depositional record of the northwestward ice-flow event is quite comparable to that of the ensuing glacial phase, and it is thus thought to represent the Early Wisconsinan glacial maximum. In view of the large regional extent of the northwestward ice-flow phase, it must postdate the early buildup of the ice sheet. Along the southeastern Hudson Bay coast, the Late Wisconsinan westward glacial movement was followed by a southwestward deflection that was likely caused by glacial streaming prior to 8000 BP in James Bay, in response to calving and surging into Glacial Lake Ojibway.

Late Quaternary Glaciation and Postglacial Stratigraphy of the Northern Pacific Margin of Canada

1999 ◽  
Vol 51 (2) ◽  
pp. 113-123 ◽  
Author(s):  
J. Vaughn Barrie ◽  
Kim W. Conway
Keyword(s):  
North America ◽  
Sea Level ◽  
Late Quaternary ◽  
Energy Levels ◽  
Northwestern Pacific ◽  
Northern Coast ◽  
Stratigraphic Sequence ◽  
Queen Charlotte Islands ◽  
Quaternary Glaciation ◽  
Late Wisconsinan

AbstractAreas of southeastern Alaska and the Queen Charlotte Islands of the northwestern Pacific coast of North America were considered to be ice free during the late Wisconsinan glaciation and glacial refugia existed. However, a glacier extended from mainland North America to the shelfbreak in Dixon Entrance separating Alaska and the Queen Charlotte Islands. Glacial retreat to the east began sometime after 15,000 to 16,00014C yr B.P. and ice had completely left Dixon Entrance by 13,500 to 13,00014C yr B.P. A rapid sea-level regression occurred soon after deglaciation began, due to isostatic rebound, with relative sea level falling to approximately 150 m below present in central Dixon Entrance, decreasing the size of the inlet by about 30 percent by 12,40014C yr B.P. The late Quaternary glacial and postglacial stratigraphic sequence is more than 100 m thick overlying older Pleistocene sediments and Tertiary bedrock. A late Wisconsinan diamicton is overlain by glaciomarine muds formed between approximately 14,400 and 13,00014C yr B.P. Contemporaneous with the deposition of the glaciomarine muds an extensive outwash deposit formed off the northern coast of the Queen Charlotte Islands to a present depth of 150 m. During the sea-level lowstand and subsequent transgression, a reworked sand unit was deposited over much of the seafloor to depths greater than 450 m. The unit is exposed at the seafloor over much of the region, suggesting that seabed hydrodynamic energy levels were high after 13,00014C yr B.P. and remain so today.

Late Quaternary sedimentation in St. George's Bay, southwest Newfoundland: acoustic stratigraphy and seabed deposits

1990 ◽  
Vol 27 (7) ◽  
pp. 964-983 ◽  
Author(s):  
J. Shaw ◽  
D. L. Forbes
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Relative Sea Level ◽  
Seismic Reflection Data ◽  
Coarse Sediment ◽  
Reflection Data ◽  
Late Wisconsinan ◽  
Acoustic Facies ◽  
Glaciogenic Sediments ◽  
Glaciomarine Sediments

Shallow seismic reflection data collected in St. George's Bay, southwest Newfoundland, reveal a complex pattern of subsurface topography and acoustic facies. Two basins in the inner bay are underlain by glacially overdeepened valleys that extend to depths in excess of 180 m. Within the thick Quaternary sequence in the inner bay we recognize eight acoustic units. Units 1 (ice contact), 2 (subaqueous outwash), and 3 (draped glaciomarine) record the presence and retreat of a major Late Wisconsinan ice margin. Unit 4 (postglacial mud) has resulted from reworking of glaciogenic sediments in response to changes in relative sea level. Unit 5 (postglacial sand) is a shoreface deposit on the seaward front of the former moraine. Unit 6 (postglacial delta) was formed by fluvial reworking of glaciogenic sediments during the postglacial lowstand of relative sea level. Unit 7 (postglacial barrier–platform) comprises seaward-fining clinoform prisms that have prograded into the basins, and underlie gravel beach-ridge plains at Stephenville and Flat Island. Unit 8 (postglacial spillover) results from entrainment of coarse sediment on the shallow sill and subsequent progradation into the basins of the inner bay.Seabed sediment in the basins is mud where sampled. The submarine platforms associated with the barriers at Stephenville and Flat Island are largely sandy. The sill is covered by a gravel veneer, with irregular patches of sand that coalesce and thicken seawards. Extensive areas of gravel ripples testify to the continued mobility of much of the coarse sediment on the sill.A major ice front in the inner bay was present prior to 13.7 ka BP. The draped glaciomarine sediments, dated at 13.7–11.2 ka BP in nearby Port au Port Bay, were deposited after withdrawal of the ice front to the vicinity of the present coast, during a readvance, and subsequently. During the postglacial lowstand of relative sea level much of the present sill area was emergent.

Sign in / Sign up

Export Citation Format

Share Document