Articles tagged with: Physical Geography

  • New research by geography alumnus looks at fire history in southwest Yukon Territory

    Tuesday, December 04, 2018 | By

    Student in forest taking a tree core sample

    Tyler Prince taking a tree core sample in southwest Yukon Territory. Photo by Kevin Turner.

    New research by Tyler Prince (Brock Geography and Master of Sustainability alumnus), Michael Pisaric, and Kevin Turner was published this week in Frontiers in Ecology and Evolution. Read more below.

    Abstract:

    Previous research suggests climate warming during the current century is likely to lead to an increase in the frequency and severity of wildfire. Recent wildfire seasons in northern Canada generally support these studies, with some of the worst fire seasons on record occurring during the past decade. While we can readily track the spatial and temporal distribution of these events during recent decades using satellite-derived data, historical records of past fire activity are relatively short. Proxy records of past fire activity are needed to fully understand how fire regimes may be shifting in response to changing climatic conditions. A high-resolution fire record, dating back to the early-Holocene, has been reconstructed using a 512-cm sediment core collected from a small lake in southwest Yukon Territory, Canada. Macroscopic charcoal was counted throughout the core at contiguous 0.5-cm intervals. The core was also analyzed for loss-on-ignition and magnetic susceptibility. Fossil pollen preserved in the lake sediment was analyzed to determine vegetation change throughout the Holocene. Macroscopic charcoal analysis indicates an active fire history throughout the record, with 90 fires occurring throughout the Holocene. CharAnalysis indicates an average signal to noise index of 6.2, suggesting the peaks are significant and detectable from the slowly varying background level. Results suggest the fire regime in this region responds to both top-down (climate) and bottom-up (vegetation) factors. Fire return intervals changed in response to shifts in precipitation and temperature as well as the expansion of lodgepole pine into the region. The shifts in precipitation and temperature were attributed to the oscillation of the Aleutian Low pressure system and fluctuations in climate associated with the Medieval Climate Anomaly and the Little Ice Age.

    Access the full paper online.

    Prince, T., Pisaric, M., and Turner, K. (2018). Postglacial reconstruction of fire history using sedimentary charcoal and pollen from a small lake in southwest Yukon Territory, Canada. Frontiers in Ecology and Evolution, online.

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  • Students experience Ground Penetrating Radar demonstration

    Thursday, October 11, 2018 | By

    The Department of Geography and Tourism Studies would like to thank Sensors and Software Inc. for visiting our Physical Geography Field Course (GEOG 3P56) class on September 21, 2018 to host a demonstration on Ground Penetrating Radar (GPR).

    After learning about GPR and its’ applications, our students headed outside to test the GPR unit around the Brock University campus. Here are a few photos from the class:

    Student using Ground Penetrating Radar technology in GEOG 3P56 course outside on a hill

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  • Brock-led team collects samples at Crawford Lake to explore possible Anthropocene reference site

    Thursday, August 16, 2018 | By

    WEDNESDAY, AUGUST 15, 2018 | by 
    Story from the Brock News


    Brock PhD student Andrea Krueger collects water samples at Crawford Lake as part of Brock University-led research to confirm the Halton Region lake as being a possible location to define a new geologic epoch called the Anthropocene.

    It’s like taking a photograph of Earth every year for a thousand years.

    The difference is that the ‘camera,’ in this case, is a freeze core, a long, hollow aluminum tube filled with a mixture of dry ice and ethanol to cool it to minus 80 degrees Celsius.

    On Tuesday, Aug. 14, a group of researchers from three universities and led by Brock University Professor of Earth Sciences Francine McCarthy used a freeze core to gather layers of sediment spanning the last millennium from the bottom of Crawford Lake in Milton.

    Master’s student Autumn Heyd (left) and PhD student Andrea Krueger were among a Brock University-led research team studying Crawford Lake in Milton to be a possible location to define a new geologic epoch called the Anthropocene.

    The professors and student researchers from Brock, Carleton and McMaster universities used the freeze cores to collect layers of sediments from the bottom of the oxygen-free depths of the lake, creating ‘tree rings’ of sorts.

    They collected the samples in the hopes of confirming a new episode in the world’s geological time scale known as the Anthropocene.

    Sediment and rock layers give scientists clues about the Earth’s plant and animal life, human activity, and other details within the planet’s geological time scale. Earth is officially in the Holocene, but the scientific community has identified the mid-20th century as being the start of the Anthropocene.

    “Because we have those annual layers of sediment in Crawford Lake, we can tell exactly when 1950 is. We can point to a layer and say, ‘That’s 1950,’ then we have the ideal location,” says McCarthy. “Hundreds of years from now, people will be able to come here to find 1950 and that’s the important thing.”

    Gesturing to the raft, McCarthy explains what lies ahead for the research.

    “Over the next year or two, my colleagues and I, along with students, are going to be analyzing and comparing what went on before 1950 and after,” says McCarthy.

    She points out that an obvious example of time stamping would be more lead in the sediment from before gasoline went unleaded.

    If they find what they’re looking for in these sediments, the research team will make a submission to the Anthropocene Working Group (AWG), an international group charged with evaluating proposals on where evidence of the Anthropocene can be best seen.

    If the AWG were to vote in favour of using Crawford Lake, the proposal would then be evaluated by the International Subcommission on Quaternary Stratigraphy, chaired by Brock Professor of Earth Sciences Martin Head.

    Head, who is also a member of the AWG, says that the Anthropocene is distinctive from the Holocene in that that human activities have shifted the way our planet is now behaving as an integrated system.

    This shift is known as the Great Acceleration, a mid-20th century phenomenon associated with global industrialization, commercialization and a huge increase in energy use.

    “Since the beginning of the Anthropocene, we may have actually exceeded the ability of the Earth’s system to self-regulate in ways that it did before, so that’s why the Anthropocene is important on a number of different levels,” he says.

    Brock researchers at Tuesday’s sediment collection included McCarthy, Head, Professor of Geography and Tourism Studies Michael Pisaric, Biological Sciences PhD student Andrea Krueger and master’s student Autumn Heyd.

    A Brock University-led research team lowers the freeze core into Lake Crawford to collect sediments as part of an effort to identify the lake as being a possible location to define a new geologic epoch called the Anthropocene.

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