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.
Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to analyze acid residues from heavy mineral separates, polished grain mounts, and clays from sampled sediments...
data.gov
An official website of the GSA's Technology Transformation Services