Shore Platform Processes in Eastern Canada

2007 ◽  
Vol 60 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Alan S. Trenhaile ◽  
Neil J. Porter ◽  
Jacob I. Kanyaya
Keyword(s):  
Salt Weathering ◽  
Tidal Level ◽  
Abrasive Material ◽  
Eastern Canada ◽  
Wetting And Drying ◽  
The Holocene ◽  
Shore Platform ◽  
Rock Hardness ◽  
Dominant Process ◽  
High Tidal Level

Abstract This research is conducted on a mesotidal, argillite shore platform at Mont Louis in Gaspé, Québec, and on macrotidal platforms in the basalts of Scots Bay and the sandstones of Burncoat Head in Nova Scotia. Rock samples have been subjected to wetting and drying and to salt weathering cycles. The platforms were surveyed; rock hardness was determined with a Rock Test Hammer; waves were recorded in the field; and downwearing rates were measured at 56 micro-erosion meter stations over 1 to 3 years. Weathering is the dominant process at Mont Louis, although the horizontal platform may have been cut by waves at the high tidal level. Wave backwearing was much more important than downwearing by weathering during the Holocene at Scots Bay. Wave quarrying only occurs on a few scarps today, however, and without much abrasive material, slow downwearing now dominates over most of the platform surface. Waves probably help to remove loosened sand grains at Burncoat Head, thereby contributing to platform downwearing. Abrasion is also important in places, but the data suggest that backwearing by wave quarrying and probably frost has been a little more important than downwearing by abrasion and weathering during the Holocene.

scholarly journals Modelling past, present and future peatland carbon accumulation across the pan-Arctic region

2017 ◽  
Vol 14 (18) ◽  
pp. 4023-4044 ◽  
Author(s):  
Nitin Chaudhary ◽  
Paul A. Miller ◽  
Benjamin Smith
Keyword(s):  
Carbon Sink ◽  
Accumulation Rate ◽  
Arctic Region ◽  
Terrestrial Ecosystems ◽  
Cold Climate ◽  
Carbon Accumulation ◽  
Accumulation Rates ◽  
Eastern Canada ◽  
The Holocene

Abstract. Most northern peatlands developed during the Holocene, sequestering large amounts of carbon in terrestrial ecosystems. However, recent syntheses have highlighted the gaps in our understanding of peatland carbon accumulation. Assessments of the long-term carbon accumulation rate and possible warming-driven changes in these accumulation rates can therefore benefit from process-based modelling studies. We employed an individual-based dynamic global ecosystem model with dynamic peatland and permafrost functionalities and patch-based vegetation dynamics to quantify long-term carbon accumulation rates and to assess the effects of historical and projected climate change on peatland carbon balances across the pan-Arctic region. Our results are broadly consistent with published regional and global carbon accumulation estimates. A majority of modelled peatland sites in Scandinavia, Europe, Russia and central and eastern Canada change from carbon sinks through the Holocene to potential carbon sources in the coming century. In contrast, the carbon sink capacity of modelled sites in Siberia, far eastern Russia, Alaska and western and northern Canada was predicted to increase in the coming century. The greatest changes were evident in eastern Siberia, north-western Canada and in Alaska, where peat production hampered by permafrost and low productivity due the cold climate in these regions in the past was simulated to increase greatly due to warming, a wetter climate and higher CO2 levels by the year 2100. In contrast, our model predicts that sites that are expected to experience reduced precipitation rates and are currently permafrost free will lose more carbon in the future.

Modeling the Effect of Tidal Wetting and Drying on Shore Platform Development

2004 ◽  
Vol 204 ◽  
pp. 1049-1060 ◽  
Author(s):  
Alan S. Trenhaile
Keyword(s):  
Wetting And Drying ◽  
Shore Platform ◽  
Platform Development

Shifting zonal patterns of the southern boreal forest in eastern Canada associated with changing fire regime during the Holocene

2011 ◽  
Vol 30 (7-8) ◽  
pp. 867-875 ◽  
Author(s):  
Guillaume de Lafontaine ◽  
Serge Payette
Keyword(s):  
Boreal Forest ◽  
Fire Regime ◽  
Eastern Canada ◽  
The Holocene

scholarly journals Reconstructing Millennial-Scale, Regional Paleoclimates of Boreal Canada during the Holocene

2009 ◽  
Vol 22 (2) ◽  
pp. 316-330 ◽  
Author(s):  
A. E. Viau ◽  
K. Gajewski
Keyword(s):  
Climate Variability ◽  
Early Holocene ◽  
Ice Age ◽  
Western Canada ◽  
Eastern Canada ◽  
The Holocene ◽  
Northern Canada ◽  
Scale Temperature ◽  
Central Canada ◽  
Millennial Scale

Abstract Regional paleoclimate reconstructions for northern Canada quantify Holocene climate variability on orbital and millennial time scales and provide a context to better understand the current global warming. The reconstructions are based on available pollen diagrams from the boreal and low Arctic zones of Canada and use the modern analog technique (MAT). Four regional reconstructions document the space–time evolution of the climate during the Holocene. Highest summer and winter temperatures anomalies are found in central Canada during the early Holocene. Eastern Canada was relatively cool in the early Holocene, whereas central Canada was warmest at that time. Labrador was relatively dry in the early to mid-Holocene during which time western Canada was relatively moist. Millennial-scale temperature variations, especially the Medieval Warm Period and Little Ice Age are seen across the continent, with some suggestion of time-transgressive changes from west to east. At the millennial scale, precipitation anomalies are of opposite signs in eastern and western Canada. The results herein indicate that modern increases in temperatures in northern Canada far exceed natural millennial-scale climate variability.

Tree biomass reconstruction shows no lag in postglacial afforestation of eastern Canada

2016 ◽  
Vol 46 (4) ◽  
pp. 485-498 ◽  
Author(s):  
Olivier Blarquez ◽  
Julie C. Aleman
Keyword(s):  
Climate Change ◽  
Forest Ecosystems ◽  
Transfer Functions ◽  
Carbon Sources ◽  
Annual Precipitation ◽  
Biomass Estimation ◽  
Total Biomass ◽  
Tree Biomass ◽  
Eastern Canada ◽  
The Holocene

Forest ecosystems in eastern Canada are particularly sensitive to climate change and may shift from carbon sinks to carbon sources in the coming decades. Understanding how forest biomass responded to past climate change is thus of crucial interest, but past biomass reconstruction still represents a challenge. Here we used transfer functions based on modern pollen assemblages and remotely sensed biomass estimation to reconstruct and quantify, for the last 14 000 years, tree biomass dynamics for the six main tree genera of the boreal and mixedwood forests (Abies, Acer, Betula, Picea, Pinus, Populus). We compared the mean genera and total biomass with climatic (summer temperatures and annual precipitation), physical (CO2, insolation, ice area), and disturbance (burned biomass) variables to identify the potential drivers influencing the long-term trends in tree biomass. For most genera, tree biomass was related to summer temperature, insolation, and CO2 levels; Picea was the exception and its biomass also correlated with annual precipitation. At the onset of the Holocene and during the Holocene Thermal Maximum (ca. 10 000–6000 BP), tree biomass tracked the melting of the Laurentide Ice Sheet with high values (>50 tonnes·ha–1 and a total of 12 Pg). These values, in the range of modern forest ecosystems biomass, indicate that trees were probably able to survive in a periglacial environment and to colonize the region without any discernible lag by tracking the ice retreat. High biomass at the beginning of the Holocene was likely favoured by higher than present insolation, CO2 levels higher than during the Last Glacial Maximum, and temperature and precipitation close to present-day levels. Past tree biomass reconstruction thus brings novel insights about the drivers of postglacial tree biomass and the overall biogeography of the region since the deglaciation.

Shore platform downwearing in eastern Canada; A 9–14 year micro-erosion meter record

Geomorphology ◽  
2018 ◽  
Vol 311 ◽  
pp. 90-102 ◽  
Author(s):  
Alan S. Trenhaile ◽  
Neil J. Porter
Keyword(s):  
Eastern Canada ◽  
Shore Platform

scholarly journals Modelling past, present and future peatland carbon accumulation across the pan-Arctic

2017 ◽  
Author(s):  
Nitin Chaudhary ◽  
Paul A. Miller ◽  
Benjamin Smith
Keyword(s):  
Carbon Sink ◽  
Accumulation Rate ◽  
Far East ◽  
Terrestrial Ecosystems ◽  
Cold Climate ◽  
Carbon Accumulation ◽  
Accumulation Rates ◽  
Eastern Canada ◽  
The Holocene

Abstract. Most northern peatlands developed during the Holocene, sequestering large amounts of carbon in terrestrial ecosystems. However, recent syntheses have highlighted the gaps in our understanding of peatland carbon accumulation. Assessments of the long-term carbon accumulation rate and possible warming driven changes in these accumulation rates can therefore benefit from process-based modelling studies. We employed an individual- and patch-based dynamic global ecosystem model with dynamic peatland and permafrost functionality and vegetation dynamics to quantify long-term carbon accumulation rates and to assess the effects of historical and projected climate change on peatland carbon balances across the pan-Arctic. Our results are broadly consistent with published regional and global carbon accumulation estimates. A majority of modelled peatland sites in Scandinavia, Europe, Russia and Central and eastern Canada change from carbon sinks through the Holocene to potential carbon sources in the coming century. In contrast, the carbon sink capacity of modelled sites in Siberia, Far East Russia, Alaska and western and northern Canada was predicted to increase in the coming century. The greatest changes were evident in eastern Siberia, northwest Canada and in Alaska, where peat production, from being hampered by permafrost and low productivity due the cold climate in these regions in the past, was simulated to increase greatly due to warming, wetter climate and greater CO2 levels by the year 2100. In contrast, our model predicts that sites that are expected to experience reduced precipitation rates and are currently permafrost free will lose more carbon in the future.

Modelling tidal notch formation by wetting and drying and salt weathering

Geomorphology ◽  
2014 ◽  
Vol 224 ◽  
pp. 139-151 ◽  
Author(s):  
Alan S. Trenhaile
Keyword(s):  
Salt Weathering ◽  
Wetting And Drying
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