ice cores Flashcards
what is the only data is typically available at the earths highest latitudes and altitudes
ice
how can ice be measured
bubbles trapped within the ice capture the gas concentration of our well-mixed atmosphere, while the ice itself records other properties, providing a window into 800,000 years of past climates
how are ice cores obtained
scientists obtain this information by using a specialised drill that bores down into ice sheets, like Antarctica or Greenland, and removing a cylindrical tube called an ice core
what is the Vostok core
a joint team of Russian, United states and French teams working at the Russian Vostok station in Antarctica in 1987
the ice core was 3190 m long making it the largest ice core ever and dating back around 800,000 years before present
how do ice cores form
these cores contain distinct layers that form throughout the years, with each passing year, snow falls over the ice sheets and each layer of snow has a different texture and a different chemistry, with winter and summer snow differing
what happens to the ice in summer
in summer when the sun is shining 24 hours a day, the top layer of the snow changes in texture
what happens to the ice in winter
in winter when it turns cold and dark, new snow falls on top of the summer snow forming distinct layers
this gives scientists with vast information about climate each year
what do they tell scientists about
ice cores can tell scientists about temperature, precipitation, atmospheric composition (CO2 levels) , volcanic activity, and even wind patterns
what does the thickness of each layer show
allows scientists to determine how much snow fell in the area during a particular year
wind patterns can be based on where the snow drifted, which can be interpolated from the thickness of the layers in the core
what does testing trapped air bubbles show
the chemical composition of the snow itself can tell scientists about temperatures in the area, as colder temperatures lead to a higher concentration of heavier oxygen isotopes in the snow
what else can be found in the layers of an ice core
dust from nearby locations can also accumulate in the layers of ice cores
gigantic volcanic eruptions anywhere on the globe can spew enormous quantities of dust into the atmosphere that can accumulate in the ice
how do they get dated and show the climate at the time
all the dust layers, combined with the chemical composition of the ice and a flow model that assesses how ice accumulates over time
what many years of climatic data have been collected from ice cores
400,000 years of climatic data have been collected from ice cores illustrating 4 different distinct climate cycles of temperature increases and decreases
these changes result in
positive correlation and relationship with the chemical composition and dust pattern taken from the cores
