| Title | Insights into the Connaught sequence of the Timiskaming varve series from Frederick House Lake, northeastern Ontario |
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| Author | Brooks, G R |
| Source | Canadian Journal of Earth Sciences 2021 p. 1-15, https://doi.org/10.1139/cjes-2020-0217 |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20200566 |
| Publisher | Canadian Science Publishing |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| Related | This publication is related to Thickness record of varves
from glacial Ojibway Lake recovered in sediment cores from Frederick House Lake, northeastern Ontario |
| File format | pdf; html |
| Province | Ontario |
| NTS | 42A/10; 42A/11; 42A/14; 42A/15 |
| Area | Frederick House Lake |
| Lat/Long WENS | -81.1667 -80.5000 49.0000 48.5000 |
| Subjects | surficial geology/geomorphology; stratigraphy; geophysics; Science and Technology; Nature and Environment; lake sediments; varves; clastics; lake sediment thickness; landslide deposits; geophysical
surveys; acoustic surveys; systematic stratigraphy; disconformities; glacial history; glaciation; depositional history; lake sediment cores; Connaught Sequence; Timiskaming Series; Glacial Lake Ojibway; Matagami Series; Laurentide Ice Sheet; Cochrane
Advance; lacustrine sediments; colluvial and mass-wasting deposits; glaciolacustrine sediments; Phanerozoic; Cenozoic; Quaternary |
| Illustrations | location maps; geophysical profiles; tables; lithologic logs; geophysical images; time series |
| Program | Public
Safety Geoscience Plate Boundary Earthquakes |
| Released | 2021 05 13 |
| Abstract | 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,
Canada. 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 underlie and overlie the MTD. Comparison to regional published
varve series reveals two possible interpretations for the varve numbering: varve (v) 2066 to v2115, which requires the inference of a 55 varve year (vyr) disconformity just below the Connaught sequence, while the alternative numbering, v2011a to
v2060a (a = alternative), extends continuously from older varves. Circumstantial evidence supporting the alternative numbering is as follows: (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 about 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 v2074a rather than v2129 in the original numbering. |
| Summary | (Plain Language Summary, not published)
Clastic varves are sediments that accumulate in glacial lakes. Similar to tree rings, they can be used to date deposits or features in glacial lakes.
This paper is identifies and corrects a discrepancy to the numbering of the youngest varves in Timiskaming varves series. These varve accumulated in glacial Lake Ojibway, northeastern Ontario-western Quebec, as the Laurentide Ice Sheet was receding
in the region. |
| GEOSCAN ID | 327798 |
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