About the blog: What Things Are Made Of
AMERICA'S GLOBAL DEPENDENCY FOR NEARLY EVERYTHING
Sunday, February 28, 2010
In a previous post I mentioned gypsum in Oklahoma, precipitating out of seawater on a hot, arid equatorial coastline 255 million years ago. A good modern analog for this is Umm Sa'id Sabkha, on the east coast of Qatar along the Persian Gulf (or Arabian Gulf if you prefer), in the photo below.
Lots of mineral deposits can’t be explained by direct analogs—for example, we can’t really look at the roots of a modern volcano to observe the processes that may be concentrating ores there. But inferences from modern situations are probably the best way we have of understanding unusual mineral bodies and predicting where to find more.
“The present is the key to the past” – a concept first clearly expressed by Scottish geologist James Hutton in 1795 (but probably not in those exact words).
Images – Sabkha NASA, black smoker NOAA