3949
After coming up with a fairly accurate estimate of the age of the earth , he turned to investigating the lead contamination problem by examining ice cores from countries such as Greenland .
 location: Greenland
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 location: Greenland