The 5th Extinction: The K-T Boundary and How to Find it

Anyone that’s seen Jurassic Park, or any of its summer-fixture spinoffs, knows that dinosaurs lived large. There was never a bigger badass than T. rex.

And even though he ruled the West, he flamed out just as quickly as his meek brethren in a fantastic fireball 66 million years ago.

This was the fifth time that our very own Mother Earth has tried to eliminate all life on both land and sea, and this extinction event is known as the K-T Boundary.

“In fittingly sensational form, their deathblow was catastrophically abrupt and mind-bendingly spectacular. At the end of the Cretaceous, the largest asteroid known to have hit any planet in the solar system in a half-billion years hit Earth” — Peter Brannen, The Ends of the World: Volcanic Apocalypses, Lethal Oceans, and Our Quest to Understand Earth’s Past Mass Extinctions.

If you’re still wondering if the trip to Trinidad Lake State Park in southeastern Colorado is worth the effort, in his excellent book Peter Brannen goes on to say:

  • A rock larger than Mt. Everest hit planet earth, near Chicxulub, Mexico traveling twenty times faster than a bullet.
  • It compressed the air below it so violently that it briefly became several times hotter than the surface of the sun.”
  • The asteroid instantaneously put a hole in the ground more than 20 miles deep … and stretching more than 60 miles wide.”
  • The enormous gash in the Yucatan remained hot for 2 million years after the extinction.”
  • Most dinosaurs were literally roasted in their tracks.

In earth’s history, there’s probably never been anything as spectacular as this explosion, but by the time this 5th Extinction was written into the rock record it was a thin bed of gray claystone.

“Rock Stars” aren’t always obvious and don’t always locate themselves for your convenience, and this is the case with the K-T boundary. It’s not hard to find, but it’s also not easy, so to avoid roaming around the countryside, these directions will get you there:

Trinidad, Colorado is 200 miles south of Denver on Interstate 25; and Trinidad Lake State Park is on Hwy 12, just west of town. Your journey begins at the State Park Visitors’ Center.

  1. At the Visitors’ Center pay your daily fee and pick up a trail brochure – Mention that you’re there for the K-T Boundary: it’s a guaranteed conversation starter.
  2. Drive back to the main park entrance and take Hwy 12 west for 5.1 miles.
  3. At a brown sign “Long’s Canyon Viewing Area” turn left and cross the bridge.
  4. Proceed to County Rd 18.3 and take it into Long’s Canyon.

5. Continue on this road to the parking areas. There are two, and you can park at either one, but if you want to shorten your hike a bit, continue to the second turnaround which has a locked gate on the roadway. The trailhead is ahead and well marked. 


If you’d like to check the location beforehand and print up a map, go to Google Maps and search: “K-T Boundary, County Road 18.3, Cokedale, CO” 

If you’ve made it this far in the post, I hope you’re hooked and making plans. The K-T boundary marks an incredible turning point in earth’s history, and certainly qualifies as a worthy addition to your Bucket List. Just think of all the glazed-over eyes at your next cocktail party.

Happy Trails,

P. S. Ground zero for the asteroid was near the town of Chicxulub (CHEEK-shə-loob), Mexico in the northern Yucatan. Our blogging buddy Joe at Month at A Time Travel visited the small town, and wrote this very informative post. Check it out.

P.P.S. And if you haven’t had enough, we’ll leave you with some corny dinosaur puns. 🙂 

Photo Credits: 1.  Amy Baugess 3. Uwe Dedering


We're Terri and James Vance - high school sweethearts who went on to international careers and became world nomads. Today, 65 countries later, we're still traveling ... and still in love. Check out Our Story for more of the backstory at

32 thoughts

  1. Wow! Really interesting. I spent a year commuting to Trinidad for a work project and never knew about this. But back that, work was all consuming. Fascinating information.

    1. Ingrid, don’t feel so bad. In college, I spent two months in the Rockies in a geologic field mapping class, and had never heard of this important contact. Why? I’ll never know. However, I can probably appreciate it more now anyway. Trinidad is an interesting little place and the area around town is very cool. What were you doing there? ~James

      1. At the time, we were a custom/semi-custom home builder throughout Pueblo County. We contracted to build a custom home on a new Golf Course Community just north of town (Trinidad). The project was a challenge on multiple levels one of which was the 100 mile one way commute.

  2. With detailed directions as the ones you’ve included, we have no excuse not to search and find, but we still may not make it. I’m just glad you included all these photos and this good information about something that sounds rather cataclysmic but also virtually unheard of by many people, including us. You’ve brought it to our attention now, though. And Wow! What an event in history!

    1. Rusha, in the worlds of geology and paleontology, extinction events are well known and extensively studied. And up until the popularity of the dinosaurs, most people had no idea of their occurrence. But global warming has given the study of extinction events a whole new importance, because of carbon dioxide in the atmosphere. In past extinction events climate change, precipitated or exacerbated by excessive amounts of carbon dioxide in the atmosphere, were just as serious and damaging as meteorite impacts. And when it comes to the greenhouse effect, carbon dioxide is the same whether it comes from Volvos or volcanoes. I don’t want to be a doomsayer, but maybe this might be a topic for another post. ~James

      1. Your posts are always interesting, so I hope you do write something about what might be ahead. In the meantime, I’ll watch out for asteroids, especially the ones bigger than Mt. Everest!

      2. Geology is a science that can really only be taught and studied over a lifetime. There is no end to it’s fascinating secrets. It is not about the rocks but instead is about how life ebbs and flows according to the rocks. I recently have been reading how lake Bonneville was much much larger than the current Salt Lake which even now is schriveling (sic) due to the increase in temperature. Lake Bonneville would have been a marvelous aguatic resource for multiple uses. Very small changes in temperature either decrease the lake or increase it through evaporation as it has no outlet. Very interesting and sad as it will become even more saline as it shrinks.
        Short story, we are screwed.

      3. Thanks for the comment Gene and for dropping by the blog. If there’s anything the 5 major extinction events have taught us it’s that our planet is pretty good at generating its own catastrophes that wipe out huge portions of the life on its surface and in its oceans. However, we’ve also learned that given enough time life finds a way to start over and flourish. That’s not to say that humans aren’t having a huge impact on the atmosphere and climate of earth that we will eventually pay for. But Homo Sapiens didn’t get to be the dominant species by being unable to adapt, and I’m hopeful that eventually we’ll come to our senses. The real question is whether we’ll change our ways voluntarily or out of desperation. ~James

  3. An incredible place and certainly one for the travel wish list. I find the history of dinosaurs fascinating and to think these creatures did really exist, it is mind boggling. Thanks for the detailed directions to this amazing place.

    1. Gilda, I hope you get a chance to see the K-T boundary and the American West. There’s so much unique beauty there. But you’ve probably already seen another place that’s on my geologic bucket list: the Mid-Atlantic Ridge that comes ashore in Iceland. As you might know, the ridge is boundary between the North American and Eurasian tectonic plates and it’s another very big deal – at least to geeks like me. We weren’t able to see it when we passed through. If you got a chance to see it, I’m très envious. Did you guys see it when traveling around Iceland? ~Jamees

  4. James, I found this trip to K-T boundary to be rather timely. At a time when the UN climate change movement is finally starting to take hold, we are losing species at an alarming rate of 200 species per day!!! While not the catastrophic instant roasting of all living things, ti is a slow gaining speed march toward systemwide extinction, ie.the sixth extinction.


    1. Ben, with the exception of the extinction event that eliminated the dinosaurs, all the other events were gradual affairs. From the standpoint of geologic time, they could have been considered rapid, but we humans see and experience things in terms of centuries, not millennia. So your phrase “slow gaining of speed” is a good one.

      Opponents on both sides of the argument cherry-pick the data to make their case, but when you look at the body of data, no reasonable person can deny that species loss is happening at an alarming rate, as is global warming produced by the addition of carbon dioxide into the atmostphere. ~James

  5. I’d never heard of the K-T Boundary. It’s hard to imagine something so catastrophic in our history left such a thin layer to record it ever happened. I think it is fascinating something that happen SO long ago is accessible at the earth’s surface. Neat post!

    1. Thanks Laura. I’m biased of course, but with a little of the backstory, I would think just about everyone would find this fascinating … but then that’s just the nerd talking. And I don’t know if you looked at the map, but when you visited Palo Duro Canyon in the Texas panhandle you weren’t that far from Trinidad. Next time up that way, you might want to take Waldo for a little geologic field trip. ~James

  6. James, Thank you for referencing my Chicxulub post. I have edited the post to add a link to your excellent field trip report. The two posts make good companions for anyone interested in this amazing subject.

    1. I thought you might like this post Pam. Because you know a bit about geology, I’m sure you know what a big deal this contact is. I hope you can get to see it sometime. ~James

    1. Thanks for the link to your post on the Royal Tyrell Museum of Palaeontology. I haven’t visited, but from your post and photos it looks like the perfect museum for dinosaur fans. Thanks again. ~James

    1. Jackie, I’m biased of course, but I find this topic fascinating as well. From my days of working in oil exploration in the London, I don’t think the KT boundary is present in the UK (possibly eroded away). However, I’m sure your friend Sheila knows more about it, and I’d love to hear here thoughts. Take care. ~James

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