Macrofossil, pollen, and geochemical records of peatlands in the Knosheo Lake and Detour Lake areas, northern Ontario

Abstract

The macrofossil and pollen records from two cores in the Detour Lake and Kinosheo Lake peatlands in northeastern Ontario cover more than 7000 years and 4000 years of vegetation history, respectively, and record a succession of peatland environments. The Detour Lake pollen record includes the vegetation successions associated with two major climatic shifts, the Mid-Holocene warm period and Late Holocene cooling trend. From 4000 BP, the vegetation successions derived from pollen analysis correlate well with respect to the evolution of the peatland and surrounding upland vegetation. Similar patterns of change were also noted in the pollen and macrofossil stratigraphies from other parts of northern Ontario. Patterns of trace element distribution reflect major changes in the peatlands. The most notable is the decrease in most trace elements as the peatland evolved from minerotrophic to ombrotrophic conditions. Levels of many elements are enriched in the near-surface peat horizons. Based on the data from this study, it is not possible to identify which part of the surface enrichment reflects airborne anthropogenic pollutants, inputs from naturally occurring atmospheric sources, or the relocation of inorganic constituents by physical, chemical, or biological processes.

Relative importance of hydrological and climatic controls on Holocene paleoenvironments inferred using diatom and pollen records from a lake in the central Hudson Bay Lowlands, Canada

“…The timing of the major shift in diatoms from Fragilarioids to large benthics, and the development of the Equisetum marsh (following 6200 cal. BP) is broadly coincident with inferred onset of maximum Holocene temperatures for the HBL region, based on the admittedly few available records (Kettles et al, 2000;McAndrews et al, 1982), and for comparable subarctic sites in eastern North America (Kaufman et al, 2004;Paul et al, 2010;Payette and Filion, 1993). However, the dominance of C. diluviana, a species commonly associated with cool, brackish postglacial environments or stagnant ice conditions (Florin, 1970;Robertson, 1995;Stoermer et al, 1988), through diatom Zones 2 and 3 and throughout the inferred HTM suggests that while temperatures may have been warmer compared with the preceding period, the local climatic warming may have been of lower magnitude compared with other subarctic sites.…”

Pollen and macrofossil‐inferred palaeoclimate at the Ridge Site, Hudson Bay Lowlands, Canada: evidence for a dry climate and significant recession of the Laurentide Ice Sheet during Marine Isotope Stage 3

“…Sites not previously included in the NAMPD were obtained from several sources, including Potzger & Courtemanche (), Terasmae & Hughes (), Lichti‐Federovich & Ritchie (), Terasmae & Anderson (), Skinner (), Farley‐Gill (), Bazely (), Kettles et al . (), Dredge & Mott (), Glaser et al . (), Friel et al .…”

Climate and peat type in relation to spatial variation of the peatland carbon mass in the Hudson Bay Lowlands, Canada

“…Quantification of the peatland C mass was based upon detailed analysis of 42 peat cores for bulk density, loss on ignition (LOI) and/or C content measurements (Table ), using previously described methods [ Packalen and Finkelstein , ; Packalen et al ., ]. Of these, 11 are evaluated from previously published studies [ Bunbury et al ., ; Holmquist et al ., ; Kettles et al ., ; Kuhry , , ; O ' Reilly et al ., ; van Bellen et al ., ], while new detailed peat physical characteristics for 31 previously described peat cores are presented [ Packalen and Finkelstein , ; Packalen et al ., ]. C mass was calculated for all samples, by summing the product of incremental C density and increment length, and was linearly related to peat depth (Figure ) for the range of peat depths considered here.…”