geologic history

The June Accretionary Wedge, "Let's Do a Time Warp," is up at Outside the Interzone. It's a crazy time-machine ride from before the Big Bang all the way into the tectonic future. Come along with the geology bloggers to a few of our favorite times. (And, no, the Cretaceous-Tertiary Paleogene boundary didn't make anyone's list. But you'll have to go to the post to find out what did.)
I bet I'm not the only geologist who always wants to list "time machine" in the budget request for every grant proposal I write. Yes, we've got a lot of tools to sort out what's happened in the past, but wouldn't it be a lot easier if we could just go back and see for ourselves? So I love this month's theme for the reactivated Accretionary Wedge carnival. I want to go back about 1.7 billion years, to see what on Earth was happening when my favorite local rock was being deposited. This is the Vallecito Conglomerate. It's been metamorphosed, but its sedimentary features are still preserved. It'…
The Accretionary Wedge, the monthly carnival of geology, is still alive! Or, well, it's still active, at least. Its originator, Brian, got too busy to keep it up, so he handed off responsibilities to Lockwood (of Outside the Interzone), Chris (of goodSchist and the Podclast), and me. Lockwood will be hosting the next Accretionary Wedge, in mid-June. His theme: Let's Do a Time Warp! So your mission, should you choose to accept it, is this: "Where and when would you most like to visit to witness and analyze an event in Earth's history?" Suppose you have a space-time machine to (safely and…
My husband and I both had goals for our visit to the Grand Canyon at the beginning of this week. He wanted to give himself a workout that would leave him feeling sore all week. I wanted to check out the Trail of Time, an exhibit that some of my colleagues from New Mexico and Arizona had been developing. I didn't know whether it was complete, or where it started, but I'd been hearing Karl Karlstrom and Laurie Crossey talk about it for years. The rangers working at the main visitor center had heard about it at a briefing, and had some pamphlets hidden behind their desk, but weren't quite sure…
Geotripper got a new camera for his birthday, and has been taking pictures of mountains. I haven't posted enough pictures since I got my camera in December, so here's a view of my daily commute: Here, let me label it for people who don't make a habit of seeing geology in landscapes (picture below fold): The dreaded Mancos Shale, which is found on all the lower slopes in the background, was deposited near the western shore of the great interior seaway of North America, about 90 million years ago. My colleagues who are into fossils tell me that there are some massive clam shells in it, if you…