NationalGeographic.com [an error occurred while processing this directive]


 
Zoom In

TimeSigns



<< Back to Feature Page




View exclusive photographs and get the facts behind the frame.

TimeSigns Zoom In Thumbnail 1
Click to ZOOM IN >>

TimeSigns Zoom In Thumbnail 2
Click to ZOOM IN >>

TimeSigns Zoom In Thumbnail 3
Click to ZOOM IN >>

TimeSigns Zoom In Thumbnail 4
Click to ZOOM IN >>

TimeSigns Zoom In Thumbnail 5
Click to ZOOM IN >>



TimeSigns Zoom In 3

Hard Core
Photograph by Peter Essick

Glaciologists Victor Zagorodnov, left, and Patrick Ginot extract a section of a 550-foot (170-meter) core from the summit of Peru's Quelccaya ice cap, at an elevation of about 18,600 feet (5,670 meters). The ratio of certain oxygen isotopes in the ice varies with temperature, enabling scientists to distinguish cold periods from warm periods over thousands of years. Rising temperatures are causing Quelccaya—the world's largest tropical ice cap—to retreat rapidly. Its major outlet glacier has receded nearly 3,100 feet (950 meters) since 1963—the smallest it's been in about 5,000 years.

Photo Fast Facts

Camera: Canon EOS 1V
Film Type: Fujichrome Provia 100
Lens: 17-35mm
Speed and F-Stop: 1/125 @ f/11
Weather Conditions: Sunny
Time of Day: Late afternoon
Lighting Techniques: Natural light


© 2004 National Geographic Society. All rights reserved. Privacy Policy       Advertising Opportunities       Masthead

National Geographic Magazine Home Contact Us Forums Shop Subscribe