Miami Herald: Frozen crystals packed with concentrated natural gas and buried 2,000 feet below the permafrost on Alaska’s North Slope could become the next major domestic energy source, according to an assessment released Wednesday by the U.S. Geological Survey. The study finds that in the North Slope, frozen methane-and-water crystals known as hydrates contain as much as 85.4 trillion cubic feet of recoverable natural gas. That’s enough to heat 100 million homes for as long as 10 years, Interior …