Dating events using ice Real porn dating site
Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper, and an ice core contains ice formed over a range of years.Cores are drilled with hand augers (for shallow holes) or powered drills; they can reach depths of over two miles (3.2 km), and contain ice up to 800,000 years old.Ice cores are expensive to collect, house and keep.They must be stored continuously at a specific temperature.Because the rate of snowfall varies from site to site, the age of the firn when it turns to ice varies a great deal.At Summit Camp in Greenland, the depth is 77 m and the ice is 230 years old; at Dome C in Antarctica the depth is 95 m and the age 2500 years.Greenland ice cores contain layers of wind-blown dust that correlate with cold, dry periods in the past, when cold deserts were scoured by wind.
The bubbles disappear and the ice becomes more transparent.
The physical properties of the ice and of material trapped in it can be used to reconstruct the climate over the age range of the core.
The proportions of different oxygen and hydrogen isotopes provide information about ancient temperatures, and the air trapped in tiny bubbles can be analysed to determine the level of atmospheric gases such as carbon dioxide.
Since heat flow in a large ice sheet is very slow, the borehole temperature is another indicator of temperature in the past.
These data can be combined to find the climate model that best fits all the available data. Coastal areas are more likely to include material of marine origin, such as sea salt ions.