geologic time
khannula | September 21, 2009I confess that I didn't know the geological conventions for abbreviating time until I started teaching the geology writing class and looked them up. (That's despite having published a paper on argon-argon geochronology. Sometimes, just doing whatever the co-authors and reviewers say is the right thing to do...) So I don't have any strong opinions about how to abbreviate lengths of time. But if you do, the Geological Society of America wants to know.
Short version: traditionally, geologists have used different abbreviations for ages (time before present) and duration (amount of time elapsing…
khannula | June 14, 2009The 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.)
khannula | May 25, 2009You would think that, with 4.6 billion years of geologic history to play with, geologists wouldn't get all hung up about a mere 2.6 million years. But when those 2.6 million years include the glacial episode popularly known as the Ice Ages (and the evolution of some weird naked ape), well... scientists can get pretty protective of their terminology.
Geological Society of America time scale
I'm neither a stratigrapher nor a historian of stratigraphy. (In fact, I tend to treat sedimentary layering as a marker that helps me keep track of the gorgeous changes in shape that rocks undergo.) I also…
khannula | May 24, 2009The 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…
khannula | April 2, 2009My 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…
khannula | March 26, 2009I've got one wallet-sized version of the 1983 Geological Society of America time scale in my field pouch, and another page-sized version that used to be taped to the wall in front of my desk. I relied on it a lot, especially when starting work in a new field area. In the early 90's, when I was trying to break into the world of Appalachian tectonics research, I started by trying to figure out where the problems were in the models of how the metamorphic rocks of New England came to be. I spent a lot of time reading papers from different subdisciplines - the records of old mountain belts are…
greengabbro | January 22, 2009One of my New Year's blogolutions was to clear out my to-blog folder, and bring closure to my unfinished drafts by simply posting them as-is. This is one of those drafts. Disorganized paragraphs, unfinished sentences, and general incoherence enhance the natural character and beauty of a half-written blog post and should not be considered flaws or defects.
Draft date: February 29, 2008
Once you have chosen an event that represents a boundary in the geologic time scale, you are left with two questions: How long did that event take? How accurately can we resolve the date at which it happened?…
greengabbro | February 1, 2008Let's get one thing out of the way right now: The question of whether or not a new geologic epoch has "really started" is precisely as stupid as the question of whether or not Pluto is "really" a planet. The definitions of geologic eons, eras, and epochs are not objective truths about the history of the planet that are simply waiting for us in the rock. The geologic time scale is made up by geologists, for geologists as a matter of convenience. So Greg Laden is making a category error when he dismisses both the Anthropocene and the Holocene as scientifically invalid - the worst thing you can…
sb admin | January 31, 2008Welcome, Gentle Reader, to my new series of Internet tubes. You'll notice that I haven't completely unpacked - there's no pretty banner at the top, the blogroll is woefully incomplete (it's probably even missing your blog!), and my profile page is not nearly as verbose as it could be. It'll get there in time.
You can expect to see this space filled in the future with rocks, water, progressive identity politics, primal screams of terror associated with my master's thesis (due in May) and/or my upcoming wedding (September), and maybe some lolcats. Oh, and pie - I am quite keen on pie. If you're…