Tuesday April 15, 2014
I try to put up basic information here, but even so I'm way ahead of most people. Fortunately they keep writing me and visiting the Forum with pictures of rocks, and that tells me they need information that's even more basic. They say, "I've looked all over and can't find a picture that looks like this." That's not how to do things. Don't look at pictures, look at your rock. Look closely at it. Study it and take notes. Start here with Rocks 101: How to Look at a Rock. That said, I've added some pictures to the article just because.
Monday April 14, 2014
Every state I study, investigating its geological highlights, I fall in love with. Georgia is definitely on my mind after compiling this gallery of geological attractions and destinations
. As always, I had to leave out as much as I included because I couldn't find good photos. So, to quote another Southern belle, I must rely on the kindness of strangers to submit them along with names of more great places to see and study rocks and related subjects.
Panola Mountain courtesy SixtyTwo Point of View of Flickr
Sunday April 13, 2014
Geologists can be ecumenical about minerals: they're all interesting for various reasons. But some minerals are more equal than others, especially when money is involved. Ores are those big-money minerals that provide the essential metals of civilized life. So jump into this week's Geo-Whiz Quiz on ores and see if you are a truly well-grounded citizen. What could be a better way to get ready for Earth Day-the-way-it-should-be?
Saturday April 12, 2014
Earth history, as recorded in rocks, begins about 3.5 billion years ago (with a few older outliers). Solar system history, as recorded on the surface of solid bodies, ends about 3.7 Ga (few younger outliers). So to study the earliest Earth, between 4.6 and 3.5 Ga, all we have to go on is the history of the greater solar system. And for that, our best tool is a crude one: counting craters. But you know, we made a lot of progress in geology, throughout the 19th and much of the 20th centuries, with crude tools just like it. My new article, "How We Date Planetary Surfaces," goes into the subject in more detail.