| Titre | The sedimentary and palynological records of Serpent River Bog, and revised early Holocene lake-level changes in the Lake Huron and Georgian Bay region |
| Auteur | Lewis, C F M; Anderson, T W |
| Source | Journal of Paleolimnology vol. 47, 2012 p. 391-410, https://doi.org/10.1007/s10933-012-9595-4 |
| Année | 2012 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20110337 |
| Éditeur | Springer |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1007/s10933-012-9595-4 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Ontario |
| SNRC | 41J/02 |
| Lat/Long OENS | -82.4167 -82.3333 46.2083 46.1667 |
| Sujets | tourbières aligotrophes; Holocène; profondeurs des eaux lacustres; épaisseur des sediments lacustres; sediments lacustres; eaux lacustres; lacs; analyses palynologiques; palynologie; palynostratigraphie;
lithostratigraphie; paléontologie; sédimentologie; Cénozoïque |
| Illustrations | location maps; sections; tables; diagrams; plots |
| |
| Programme | Études paléo-environnementales sur les changements climatiques, Géosciences de changements climatiques |
| Résumé | (disponible en anglais seulement)
Serpent River Bog lies north of North Channel, 10 m above Lake Huron and 15 m below the Nipissing Great Lake level. A 2.3 m Holocene
sequence contains
distinct alternating beds of inorganic clastic clay and organic peat that are interpreted as evidence of successive inundation and isolation by highstands and lowstands of the large Huron-Basin lake. Lowstand phases are confirmed by the presence of
shallow-water pollen and plant macrofossil remains in peat units. Twelve 14C dates on peat, wood and plant macrofossils combined with previously published 14C ages of lake-level indicators confirm much of the known early Holocene lake-level history
with one notable exception. A new Late Mattawa highstand (8,390 [9,400 cal] - 8,220 [9,200 cal] BP) evidenced by a sticky blue-grey clay bed is tied to outburst floods of glacial Lake Minong during erosion of the Nadoway drift barrier in the eastern
Lake Superior basin. A subsequent Late Mattawa highstand (8,110 [9,040 cal] - 8,060 [8,970 cal] BP) is attributed to enhanced meltwater inflows that first had deposited thick varves throughout Superior Basin. Inundation by the Nadoway floods and
possibly the last Mattawa flood were likely responsible for termination of the Olson Forest (southern Lake Michigan). A pollen diagram supports the recognized progression of Holocene vegetation, and defines a subzone implying a very dry, cool climate
about 7.8 - 7.5 (8.6 - 8.3 cal) ka BP based on the Alnus crispa profile during the Late Stanley lowstand. A new date of 9,470 ± 25 (10,680 - 10,750 cal) BP on basal peat over lacustrine clay at Espanola West Bog supports the previous interpretation
of the Early Mattawa highstand at ca. 9,500 (10,740 cal) BP. The organic and clastic
sediment units at these two bogs are correlated with other records showing coherent evidence of Holocene repeated inundation and isolation around northern Lake
Huron. Taken together the previous and new lake-level data suggest that the Huron and Georgian basin lakes were mainly closed lowstands throughout early Holocene time except for short-lived highstands. Three of the lowstands were exceptionally low,
and likely caused three episodes of offshore sediment erosion which had been previously identified as seismo-stratigraphic sequence boundaries. |
| GEOSCAN ID | 289833 |
|
|