One of the main purposes of About.com Geology is not just to answer your questions but to point you to deeper levels of knowledge. In many, many cases, the U.S. government's science agencies are where I point you. But, until further notice, the federal agencies are unfunded and that includes their websites.
A lot of government geologists are surely using their furloughs as an opportunity to take a nice field trip, and I wish them well. But I know they care about the work left on their desks, the monitoring equipment they were scheduled to visit, the samples they were supposed to process, the tests that have been interrupted and must be repeated, the messages from worried people they promised to answer, the meeting they committed themselves to attend and must now reconsider. Those furloughs are a nightmare.