scholarly journals Oxygen-isotope variations in post-glacial Lake Ontario

2016 ◽  
Vol 134 ◽  
pp. 39-50 ◽  
Author(s):  
Ryan Hladyniuk ◽  
Fred J. Longstaffe
Keyword(s):  
Oxygen Isotope ◽  
Lake Ontario ◽  
Glacial Lake

scholarly journals A younger glacial Lake Iroquois in the Lake Ontario basin, Ontario and New York: re-examination of pollen stratigraphy and radiocarbon dating

2020 ◽  
Vol 57 (4) ◽  
pp. 453-463
Author(s):  
C.F.M. Lewis ◽  
T.W. Anderson
Keyword(s):  
New York ◽  
New York State ◽  
Lake Ontario ◽  
Late Glacial ◽  
Glacial Lake ◽  
Lake Basin ◽  
Long Distance ◽  
Small Lake ◽  
Pollen Stratigraphy ◽  
Lake Basins

Revision of palynochronologic and radiocarbon age estimates for the termination of glacial Lake Iroquois, mainly based on a currently accepted younger determination of the key Picea–Pinus pollen transition, shows agreement with recently established constraints for this late glacial event in the Lake Ontario basin at 13 000 cal years BP. The date of emergence or isolation of small lake basins reflects the termination of inundation by glacial lake waters. The increasing upward presence of plant detritus and the onset of organic sedimentation marks the isolation level in the sediments of a small lake basin. The upward relative decline and cessation of pollen from trees such as Pinus, Quercus, and other thermophilous hardwoods that were wind transported long distances from southern areas also mark the isolation of inundated small lake basins by the declining water level of Lake Iroquois as local vegetation grew and local pollen overwhelmed long-distance-transported pollen. Re-examination of data in small lake basins north of Lake Ontario using the above criteria shows that the age range for the termination of Lake Iroquois derived from these data overlaps other age constraints. These constraints are based on a varve-estimated duration of post-Iroquois phases before incursion of the Champlain Sea, a newly discovered late ice advance into northern New York State, and the age of a mastodon at Cohoes, New York. The new age (13 000 cal years BP) for Lake Iroquois termination is significantly younger than the previous estimate of 11 800 14C (13 600 cal) years BP.

Timing and extent of early marine oxygen isotope stage 2 alpine glaciation in Skagit Valley, Washington

2010 ◽  
Vol 73 (2) ◽  
pp. 313-323 ◽  
Author(s):  
Jon L. Riedel ◽  
John J. Clague ◽  
Brent C. Ward
Keyword(s):  
Oxygen Isotope ◽  
Washington State ◽  
Cascade Range ◽  
Glacial Lake ◽  
Oxygen Isotope Stage ◽  
Glacier Recession ◽  
Alpine Glaciers ◽  
Valley Glacier ◽  
Skagit Valley ◽  
Sand And Gravel

Twenty-two new radiocarbon ages from Skagit valley provide a detailed chronology of alpine glaciation during the Evans Creek stade of the Fraser Glaciation (early marine oxygen isotope stage (MIS) 2) in the Cascade Range, Washington State. Sediments at sites near Concrete, Washington, record two advances of the Baker valley glacier between ca. 30.3 and 19.5 cal ka BP, with an intervening period of glacier recession about 24.9 cal ka BP. The Baker valley glacier dammed lower Skagit valley, creating glacial Lake Concrete, which discharged around the ice dam along Finney Creek, or south into the Sauk valley. Sediments along the shores of Ross Lake in upper Skagit valley accumulated in glacial Lake Skymo after ca. 28.7 cal ka BP behind a glacier flowing out of Big Beaver valley. Horizontally laminated silt and bedded sand and gravel up to 20 m thick record as much as 8000 yr of deposition in these glacially dammed lakes. The data indicate that alpine glaciers in Skagit valley were far less extensive than previously thought. Alpine glaciers remained in advanced positions for much of the Evans Creek stade, which may have ended as early as 20.8 cal ka BP.

On the origin of the Oak Ridges Moraine, southern Ontario

1985 ◽  
Vol 22 (2) ◽  
pp. 300-303 ◽  
Author(s):  
L. J. Chapman
Keyword(s):  
Lake Ontario ◽  
Glacial Lake ◽  
Stream Channel ◽  
Outlet Channel ◽  
Southern Ontario ◽  
Oak Ridges Moraine ◽  
Standing Water ◽  
Niagara Escarpment

Widespread occurrences of stratified silt and clay have been found under the surface sands on the crest of the Oak Ridges Moraine between Stouffville and Pontypool, Ontario. It is suggested that the most likely explanation for the submergence of that part of the moraine is that the Lake Ontario ice lobe was still overriding the Niagara Escarpment at the time, holding standing water in the area between the southern and northern ice lobes and the escarpment. A stream channel over the escarpment, extending from northeast of Cheltenham to Acton and beyond, may have served as the outlet. This sill is high enough to have held water over the above-mentioned silts and clays. It is of interest that this outlet channel led eventually to glacial Lake Whittlesey, indicating a correlation.

Insights into the Connaught sequence of the Timiskaming varve series from Frederick House Lake, northeastern Ontario

2021 ◽  
Author(s):  
Gregory R. Brooks
Keyword(s):  
Mass Transport ◽  
Lake Ontario ◽  
Circumstantial Evidence ◽  
Glacial Lake ◽  
Core Samples ◽  
Acoustic Profile ◽  
Lake Ojibway

A sub-bottom acoustic profile survey encountered a mass transport deposit (MTD) bed, 5-7 m thick, interbedded within glaciolacustrine deposits of glacial Lake Ojibway at Frederick House Lake, Ontario. Analysis of the thickness patterns of rhythmic couplets in recovered core samples revealed that the Connaught sequence, the youngest of the Timiskaming varve series, immediately under- and overlie the MTD. Comparison to regional published varve series reveals two possible interpretations for the varve numbering. One, varve(v) 2066 to v2115, requires the inference of a 55 varve year (vyr) disconformity just below the Connaught sequence, while alternative numbering, <i>v2011a</i> to <i>v2060a</i> (<i>a</i> – alternative), extends continuously from older varves. Circumstantial evidence supporting the alternative numbering is: i) the uncertainty of applying a common 55 vyr disconformity to three varve series located up to 23 km apart and which otherwise exhibit closely matching thickness plots; ii) the lack of evidence of an erosive unconformity in the sub-bottom acoustic profiles from Frederick House Lake; and iii) the uncertain varve count within a key part of the Matagami series, located abut 300 km away and from which the 55 vyr disconformity is extrapolated. At Frederick House Lake, the alternative numbering indicates that the maximum position of the Cochrane ice advance and the Connaught varves may be, in effect, contemporary in age. More broadly, the alternative numbering indicates that the youngest known varve that formed before the terminal drainage of glacial Lake Ojibway is <i>v2074a</i> rather than v2129 in the original numbering.

Some problems of late Wisconsin history and geochronology in southeastern Ontario

1980 ◽  
Vol 17 (3) ◽  
pp. 361-381 ◽  
Author(s):  
J. Terasmae
Keyword(s):  
Lake Ontario ◽  
Lake Huron ◽  
Glacial Lake ◽  
Radiocarbon Dates ◽  
Ottawa River ◽  
Bay Area ◽  
The North ◽  
Lake Algonquin ◽  
Surficial Deposits ◽  
Glacial Lake Algonquin

Palynological studies and radiocarbon dating of sediments from about 20 lakes and bogs in southeastern Ontario have been used to establish a palynostratigraphic sequence of six pollen zones extending to approximately 12 000 years BP and indicating that deglaciation occurred between 12 500 and 11 500 years BP, probably during the Two Creeks interstadial interval.The glacial Lake Iroquois existed in the Lake Ontario basin from about 12 500 – 11 800 years BP while the Lake Ontario ice lobe was retreating northeastward, and the Kirkfield – Fenelon Falls outlet from glacial Lake Algonquin (in the Georgian Bay – Lake Huron basin) to Lake Iroquois opened about 12 000 years ago when the Dummer Moraine was deposited as a stagnant ice disintegration feature south of the Algonquin and Haliburton Highlands.Most radiocarbon dates (about 25) on marine shells, whale bone, and algae from Champlain Sea beach deposits are in the range of 10 000 – 11 800 years BP, indicating that the Champlain Sea episode is younger than glacial Lake Iroquois. However, a few Champlain Sea dates are older than 12 000 years BP and present an unresolved problem in geochronological correlation because they conflict with proposed deglaciation histories for southeastern Ontario.Late Wisconsin ice marginal positions are poorly known in southeastern Ontario and comprise another problem for further study.The end of glacial Lake Algonquin phase (the main drainage event in the North Bay area) probably occurred between 10 800 and 10 500 years BP, after the Champlain Sea had reached its maximum western limit in the Pembroke area (upper Ottawa River valley) as indicated by stratigraphic relationships of surficial deposits.

Quaternary sequences along the north shore of Lake Ontario: Oshawa – Port Hope

1982 ◽  
Vol 19 (9) ◽  
pp. 1836-1850 ◽  
Author(s):  
M. E. Brookfield ◽  
Q. H. J. Gwyn ◽  
I. P. Martin
Keyword(s):  
Lake Ontario ◽  
Glacial Lake ◽  
Geological History ◽  
North Shore ◽  
The North ◽  
Quaternary Sequences

We describe six major stratigraphic units from the hitherto neglected Quaternary sequences along the north shore of Lake Ontario between Oshawa and Port Hope. These units, from the base upwards, consist of the following: a lowermost unit of silt till, apparently overlying bedrock; a complex unit of lacustrine and glaciofluvial sediments with several thin silt tills, usually unconformable on the lowermost unit; a glaciofluvial sand unit, filling valleys cut into the underlying units; a unit of two sandy pebbly tills; a silt till; and varved clays and sands of glacial Lake Iroquois.Though the sections show more erosional intervals, the above units can be correlated with the better known Scarborough sections as follows: the lowest unit with the Sunnybrook Till; the overlying complex unit with the Meadowcliffe Till and associated sediments; the two sandy pebbly tills with the lower Leaside Till; and the overlying silt till with the Halton Till.The inferred geological history is similar to that of the Scarborough area.

New insights on Illinoian deglaciation from deposits of Glacial Lake Quincy, central Indiana

2010 ◽  
Vol 73 (2) ◽  
pp. 374-384 ◽  
Author(s):  
J.R. Wood ◽  
S.L. Forman ◽  
J. Pierson ◽  
J. Gomez
Keyword(s):  
Oxygen Isotope ◽  
Sea Level ◽  
Lacustrine Sediments ◽  
Glacial Lake ◽  
Depositional Facies ◽  
Oxygen Isotope Stage ◽  
Fine Grained ◽  
Blue Excitation ◽  
Global Sea Level ◽  
Maximum Limit

The deposits of Glacial Lake Quincy overlie a diamicton associated with the classically defined Illinoian limit in central Indiana. This lake covered at least 180 km2 with a depth of > 20 m and developed when the Illinoian ice sheet retreated 15 km from the maximum limit, causing lake impoundment against Devore Ridge. Overflow from Glacial Lake Quincy eroded across the ridge forming a number of steeped-walled outlets. A section along Mill Creek exposes a sedimentologic sequence associated with Glacial Lake Quincy from a subglacial diamicton to ice-proximal to ice-distal glacial lacustrine sediments. We report new optical ages by multiple aliquot regenerative dose procedure for the fine-grained rhythmically bedded sediments presumed to represent the lowest energy depositional facies, dominated by suspension settling, which maximized sunlight exposure. In turn, optical ages were determined on the fine-grained (4-11 μm) polymineral and quartz fractions under infrared and blue excitation, which yielded statistically similar ages. Optical ages span from ca. 170 to 108 ka, with the average of 16 optical ages indicating deglaciation at ca. 135 ka, generally coincident with Marine Oxygen Isotope Stage 6-to-5 transition and rise in global sea level.

scholarly journals Thickness record of varves from glacial Ojibway Lake recovered in sediment cores from Frederick House Lake, northeastern Ontario

2022 ◽  
Author(s):  
G R Brooks
Keyword(s):  
Ct Scan ◽  
Sediment Cores ◽  
Lake Ontario ◽  
Core Sample ◽  
Glacial Lake ◽  
Varve Thickness ◽  
Core Samples ◽  
Visual Comparison ◽  
Original Interpretation ◽  
Lake Ojibway

The thicknesses of 384 rhythmic couplets were measured along a composite sequence of glacial Lake Ojibway glaciolacustrine deposits recovered in two sediment cores from Frederick House Lake, Ontario. The visual comparison of distinctive couplets in the CT-scan radiographs of the Frederick House core samples to photographs of core samples from Reid Lake show a match of ±1 varve number from v1656-v1902, and ±5 varve numbers between v1903-v2010, relative to the regional numbering of the Timiskaming varve series. There are two interpretations for the post-v2010 couplets that fall within the Connaught varve sequence of the regional series. In the first, the interpreted numbering spans from v2066-v2115, which produces a gap of 55 missing varves equivalent to v2011-v2065, and corresponds to the original interpretation of the Connaught varve numbering. The second spans v2011a-v2060a, and represents alternative (a) numbering for the same varves. Varve thickness data are listed in spreadsheet files (.xlsx and .csv formats), and CT-Scan radiograph images of core samples are laid out on a mosaic poster showing the interpreted varve numbering and between-core sample correlations of the varve couplets.

Late Wisconsin white spruce (Picea glauca (Moench) Voss) at Brampton, Ontario

1980 ◽  
Vol 17 (8) ◽  
pp. 1087-1095 ◽  
Author(s):  
J. Terasmae ◽  
H. L. Matthews
Keyword(s):  
Picea Glauca ◽  
Lower Boundary ◽  
Lake Ontario ◽  
White Spruce ◽  
Glacial Lake ◽  
Silty Clay ◽  
Southern Ontario ◽  
Pollen Zone ◽  
Minimum Age ◽  
Shrub Tundra

Study of late Wisconsin deposits in a small bog on the crest of Brampton esker (mantled by the Halton Till), about 30 km west of Toronto, Ontario, yielded a radiocarbon date of 12 320 ± 360 years BP (BGS-551) for a sample of white spruce cones that contained fully-developed seeds. This date on cones (in gyttja) provides an estimate of minimum age for the lower boundary of the spruce pollen zone in southern Ontario. Silty clay beneath the gyttja yielded leaves of Dryas integrifolia and pollen assemblages (a herb pollen zone) that indicate presence of a dwarf-shrub tundra (essentially treeless) type of vegetation.This study supports the Port Huron Stadial age (about 13 000 years BP) of the Halton Till that underlies the silty clay, and suggests an age of between 12 500 – 13 000 years BP for glacial Lake Peel in the Brampton area that preceded the glacial Lake Iroquois phase in the Lake Ontario basin.

Sign in / Sign up

Export Citation Format

Share Document