scholarly journals Late quaternary faulting in the Rouge River Valley, southern Ontario: seismotectonic or glaciotectonic?

1993 ◽  
Author(s):  
J Adams ◽  
L Dredge ◽  
C Fenton ◽  
D R Grant ◽  
W W Shilts
Keyword(s):  
Late Quaternary ◽  
River Valley ◽  
Southern Ontario ◽  
Rouge River

scholarly journals Time-integrated 3D approach of late Quaternary sediment-depocenter migration in the Tagus depositional system: From river valley to abyssal plain

2016 ◽  
Vol 153 ◽  
pp. 192-211 ◽  
Author(s):  
Geert-Jan Vis ◽  
Cornelis Kasse ◽  
Dick Kroon ◽  
Jef Vandenberghe ◽  
Simon Jung ◽  
...  
Keyword(s):  
Late Quaternary ◽  
River Valley ◽  
Abyssal Plain ◽  
Quaternary Sediment ◽  
Depositional System

The late Wisconsinan olistostrome of the lower Coppermine River valley, Northwest Territories

1986 ◽  
Vol 23 (11) ◽  
pp. 1700-1708 ◽  
Author(s):  
Denis A. St-Onge ◽  
Jean Lajoie
Keyword(s):  
Debris Flows ◽  
Late Quaternary ◽  
Fine Sand ◽  
Coarse Sand ◽  
Coarse Fraction ◽  
River Valley ◽  
Glacial Lake ◽  
The North ◽  
Geologic Record ◽  
Coppermine River

The late Quaternary olistostrome exposed in the lower Coppermine River valley fills a paleovalley that ranges in apparent width from 150 to 400 m and was cut into Precambrian bedrock before the last glaciation. The olistostrome is here named the Sleigh Creek Formation. The coarse fraction of the formation is matrix supported; beds are massive or reversely graded and have sharp, nonerosive contacts. These characteristics suggest deposition of the coarse fraction by debris flows. The olistostrome sequence is bracketed by, and wedged into, a marine rhythmite sequence, which indicates that deposition occurred in a marine environment.About 10 500 years BP glacier ice in the Coronation Gulf lowland dammed the valley to the south, which was occupied by glacial Lake Coppermine. Sediments accumulated in this lake in a 30 m thick, coarsening upward sequence ranging from glaciolacustrine rhythmites of silt and fine sand at the base to coarse sand alluvium, and deltaic gravels at the top. As the Coronation Gulf lowlands became ice free, the Coppermine River reoccupied its former drainage course to the north. The steep south to north gradient and rapid downcutting by the river through the glacial lake sediments produced unstable slope conditions. The resulting debris flows filled a bedrock valley network below the postglacial sea level, forming the diamicton sequence.The interpretation of the Sleigh Creek Formation raises questions concerning silimar diamicton deposits usually defined as "flowtills." More generally, the results of this study indicate that care must be used when attempting paleogeographic reconstructions of "glaciogenic" deposits in marine sequences in any part of the geologic record.

Late Quaternary paleoenvironments and growth of intrusive ice in eastern Beringia (Eagle River valley, northern Yukon, Canada)

2010 ◽  
Vol 47 (7) ◽  
pp. 941-955 ◽  
Author(s):  
Bernard Lauriol ◽  
Denis Lacelle ◽  
Mélanie St-Jean ◽  
Ian D. Clark ◽  
Grant D. Zazula
Keyword(s):  
Late Quaternary ◽  
Maximum Level ◽  
River Valley ◽  
Bison Bison ◽  
Glacial Lake ◽  
Silty Clay ◽  
Uneven Surface ◽  
Ground Ice ◽  
Fluvial Terrace ◽  
Cut Marks

In this study, the sediments exposed in a fluvial terrace and in the headwall of a thaw slump in the Eagle River valley, northern Yukon, provide new data about the timing of flooding of glacial Lake Old Crow, the formation of massive ground ice bodies, and the vegetation and the fauna in eastern Beringia during the late Quaternary. The stratigraphy and radiocarbon ages establish the following chronology of events: (1) a gravel fluvial terrace was deposited by an overflow from glacial Lake Hughes into glacial Lake Old Crow; (2) a carbonate silty clay was deposited during the maximum level of glacial Lake Old Crow at 15 120 14C year BP; (3) permafrost and large intrusive ice bodies aggraded through the glaciolacustrine and underlying sediments following the drainage of glacial Lake Old Crow from the site; (4) at 11 290 14C year BP, a shrub–sedge tundra colonized an uneven surface deformed by the bodies of ground ice; (5) a thaw lake drained at 6730 14C year BP after flooding the site; (6) during the early Holocene and from the previous major event onwards, material from the slope nearby the site buried the previous organic and inorganic sediment and the ice bodies; and (7) a bison (Bison) vertebra with conspicuous cut marks was dated to 12 210 ± 70 14C year BP. The age from the bison bone is amongst the most recent of the late Pleistocene bison specimens yet found in eastern Beringia.

Late Quaternary landscape evolution and bioclimatic change in the central Great Plains, USA

2020 ◽  
Vol 132 (11-12) ◽  
pp. 2553-2571
Author(s):  
Anthony L. Layzell ◽  
Rolfe D. Mandel
Keyword(s):  
Great Plains ◽  
Landscape Evolution ◽  
Late Quaternary ◽  
Stable Carbon Isotope ◽  
Soil Formation ◽  
River Valley ◽  
Sediment Supply ◽  
Alluvial Fans ◽  
Buried Soils ◽  
South Central

Abstract A systematic study of floodplains, terraces, and alluvial fans in the Republican River valley of south-central Nebraska provided a well-dated, detailed reconstruction of late Quaternary landscape evolution and resolved outstanding issues related to previously proposed Holocene terrace sequences. Stable carbon isotope (δ13C) values determined on soil organic matter from buried soils in alluvial landforms were used to reconstruct the structure of vegetation communities and provided a means to investigate the relationships between bioclimatic change and fluvial activity for the period of record. Our study serves as a model for geomorphological and geoarcheological investigations in stream valleys throughout the central Great Plains and wherever loess-derived late Quaternary alluvial fans occur, in particular. Holocene alluvial landforms in the river valley include a broad floodplain complex (T-0a, T-0b, and T-0c), a single alluvial terrace (T-1), and alluvial fans that mostly grade to the T-1 (AF-1) and T-0c (AF-0c) surfaces. Remnants of a late Pleistocene terrace (T-2), mantled by Holocene (Bignell) loess, are also preserved, and some Holocene alluvial fans (AF-2) grade to T-2 surfaces. Radiocarbon ages suggest that the T-1 fill and AF-1 fans aggraded between ca. 9000–1000 yr B.P. Hence, nearly all of the Holocene alluvium in the river valley is stored in these landforms. Sedimentation, however, was interrupted by several periods of landscape stability and soil formation. Radiocarbon ages from the upper A horizons of buried soils in the T-1 and AF-1 fills, indicating approximate burial ages, cluster at ca. 6500, 4500, 3500, and 1000 yr B.P. Also, based on the radiocarbon ages, the T-0c fill and AF-0c fans were aggrading between ca. 2000–900 yr B.P. Given that the T-0c fill and upper parts of the T-1 fill were both aggrading after ca. 2000 yr B.P., we suggest that the T-1 surface was abandoned between ca. 4500–3500 yr B.P., but subsequent aggradation of both the T-1 and T-0c fills occurred due to large-magnitude flood events during the late Holocene. The δ13C data indicate a shift from ∼40% C4 biomass at ca. 6000 to ∼85% at ca. 4500 yr B.P. We propose a scenario where (1) a reduction in C3 vegetation after 6000 yr B.P. destabilized the uplands, resulting in an increase in sediment supply and aggradation of the T-1 fill and AF-1 fans, and (2) the establishment of C4 vegetation by ca. 4500 yr B.P. stabilized the uplands, resulting in a reduction in sediment supply and subsequent incision and abandonment of the T-1 and most AF-1 surfaces. The proposed timing and nature of landscape and bioclimatic change are consistent with regional records from the central Great Plains.

Effects of the lampricide 3-trifluoromethyl-4-nitrophenol on diatoms in two southern Ontario streams

1987 ◽  
Vol 65 (5) ◽  
pp. 893-898 ◽  
Author(s):  
F. W. H. Beamish ◽  
K. A. Jeffrey ◽  
R. J. Kolton ◽  
P. D. MacMahon ◽  
K. A. Kowalchuk
Keyword(s):  
Community Structure ◽  
Spatial Patterns ◽  
Chemical Treatment ◽  
Diatom Community ◽  
Southern Ontario ◽  
Temporal And Spatial Patterns ◽  
Glass Slides ◽  
Temporal And Spatial ◽  
Rouge River

Diatom colonies were established on glass slides in Rouge River and Wilmot Creek before application of the lamprecide 3-trifluoromethyl-4-nitrophenol and their abundance was monitored for 21 and 55 d, respectively, after treatment. A total of 105 species of diatoms were identified from the Rouge River; of these, 23 were particularly abundant. Samples from Wilmot Creek yielded 80 species, of which 21 were dominant. Growth of the diatom community at the treated sites of Rouge River declined following chemical treatment, 8.7 mg 3-trifluoromethyl-4-nitrophenol per litre, but recovered within 21 d. Community structure and abundance in Wilmot Creek were not significantly altered by the addition of 5.3–6.7 mg 3-trifluoromethyl-4-nitrophenol per litre. No species identified from either stream exhibited particular sensitivity to the concentrations of 3-trifluoromethyl-4-nitrophenol applied. Temporal and spatial patterns of change are discussed.

Geology and paleoecology of a Middle Wisconsin fossil occurrence in Zorra Township, southwestern Ontario, Canada

2015 ◽  
Vol 52 (6) ◽  
pp. 386-404 ◽  
Author(s):  
A.F. Bajc ◽  
P.F. Karrow ◽  
C.H. Yansa ◽  
B.B. Curry ◽  
Jeffrey C. Nekola ◽  
...  
Keyword(s):  
Great Lakes ◽  
Late Quaternary ◽  
Plant Macrofossils ◽  
Great Lakes Basin ◽  
Long Distance ◽  
Southern Ontario ◽  
Oxygen Isotope Stage ◽  
Fossil Assemblage ◽  
Long Distance Transport ◽  
Organic Deposit

Nonglacial deposits of Middle Wisconsin age are being discovered with increased frequency across a broad region of southern Ontario, Canada, and provide strong evidence for a time of significant ice withdrawal from the lower Great Lakes region. With each new discovery, a refined understanding of regional climatic and paleoecological environments is emerging. In this paper, we present the results of a sedimentological and paleoecological study of a subtill organic deposit in Zorra Township, southwestern Ontario. The organic deposit, which lies beneath Nissouri Phase Catfish Creek Till (Late Wisconsin), has been dated by accelerator mass spectrometry at between 50.5 and 42.9 14C ka BP. The organic remains are contained within slack water pond deposits infilling a channel incised into till either of Early Wisconsin or Illinoian age. The fossil assemblage appears to be strongly influenced by taphonomic processes, including degradation due to oxidation, bacterial and fungal decay, and glacial overriding. Reworking and (or) recycling and selective sorting as well as long-distance transport has also influenced the composition of the fossil assemblage preserved. Nonetheless, meaningful paleoecological information is still obtained from this record. Collectively, the pollen and plant macrofossils indicate a boreal-type pine–spruce forest with temperatures cooler than present. The absence of arctic tundra plants, as are found in many other deposits of similar age in the lower Great Lakes basin, is notable. A pond or wetland inhabited by shoreline herbs, shrubs, and trees was present at or proximal to the site. The freshwater mollusc and ostracode assemblages are consistent with a shallow water habitat with dense submerged vegetation. The terrestrial mollusc assemblage suggests a taiga or transitional taiga–tundra fauna. Together, these fossil groups provide one of the most comprehensive environmental reconstructions of Middle Wisconsin time (oxygen isotope stage 3 or OIS3) in southern Ontario and serve to build on the ever-increasing database of paleoecological information accumulating for this episode of the late Quaternary.

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