Discovery News: Earth Impacts News

Triassic, You'll Like It

Alright, alright. So it's a lousy pun. Makes you kinda feel like this here onery-looking Triassic Erythrosuchian dude (drawn by Matt Celeskey of the New Mexico Museum of Natural History and Science). Don't bite my head off!
So what in blazes is the Triassic, you ask? Well let me tell you: It's not approved by the FDA, it won't lower your cholesterol or improve your libido, nor is it some sort of trinity of jackasses. Rather, it's a period in Earth's history that's sandwiched between -- and overshadowed by -- two far more famous  and charismatic times. As a result, it's one of the best kept secrets of Earth's history, you might say. But not for long.

The Triassic began with a bang -- the most extensive mass extinction event known (a.k.a. the Permian-Triassic, or just "P-T" mass extinction event) at about 250 million years ago. Then, about 45 million years later, the Triassic gives way to that movie star of geologic periods, the Jurassic. Despite this, the Triassic has a lot of tales to tell, and that's why the New Mexico Museum of Natural History and Science (NMMNHS) is in the process of developing the only hall in North America completely devoted to this step-daughter of geological periods (slated to open to the public in March, 2008). That, plus the fact that New Mexico has a whole lot of Triassic rocks and the museum is loaded with Triassic specimens.

In short, the Triassic, is the beginning of the furry tale that leads to humans (and other primates lacking furry tails). It's the dawn of the dino and the rat, if you will (pictured below is our dear little Triassic cousin, Adelobasileus, drawn by Mary Sundstrom for NMMNHS). The Triassic is also when one sort of Earth gave way to another -- the Earth of Reptiles -- and the seeds were laid for the Earth of Mammals.

There's a lot more to the tale than this, of course, and I'll be trying to hit on some of the finer points over the next few months as I track the progress of the Triassic exhibit. So as always, stay tuned. 

The Worst of Times: K-T Still Mysterious

There's a very simple rule about evolution that's often forgotten or perhaps ignored because it's so darned depressing: For anything to evolve, a whole lot of species have to go extinct. In the school of evolutionary hard knocks, extinction is a failing grade. You can't  move onto the next grade -- you're out, fossil fodder, you're (pre-)history dude. Adapt or die. Those are the only choices. Nowhere is  this cheery bottleneck of life more glaring than in the mass extinction events that pepper Earth's history. These are, to carry the school analogy to an extreme, the SAT's of evolution. The most famous of these is the Cretaceous-Tertiary boundary, 65 million years ago. It was the death-fest which ended the reign of dinosaurs, of course. For almost 30 years now folks have been pretty content with the idea that a meteor impact caused that die off. But did it? I was reluctant to accept the meteor idea back in the 80s. Seemed a little too sexy and there was a lot of political noise at the time about "nuclear winters", which seemed to piggy back on, and then reinforce the meteor impact mass extinction idea. So it has been with some interest that I've followed the work of Princeton's Gerta Keller and others who believe they have evidence of the Chicxulub meteor striking too early. They say something else did the global murdering. The leading alternative, to date, is the Deccan Traps of India. These are gigantic flood basalts which erupted and flowed across India at the same time dinos died out. The evidence for the Deccan Traps role in the K-T mass extinction is mounting. Will Chicxulub be dethroned? Probably not this year. But stay tuned for the latest in this debate which will likely raise voices and eyebrows at the Geological Society of America meeting, which starts Oct. 28.