Figure 1.
Surface soil sample collection sites in the northwest desert area along the ancient Silk Road in China. Sampling sites were marked using the red dot according to their location information.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.