Bedrock: Earth's Earliest History

While we're on a break between seasons, and while I'm starting my new job, I figured this would be a nice palate cleanser. There's no script, just answers like I'd actually give in person. If YOU want your question to be on a future Mail Time (and listen to bonus episodes), join our Patreon here ! Today, I talk about the day I fell in love with "fossil pond scum", some of my favorite field locations, and my favorite time period in Earth history. Enjoy!

Get caught up on Season 2! The Eoarchean Era covers 4 to 3.6 billion years ago, Feb 15 to March 19 on the Earth Calendar. Highlights include : the oldest rock on Earth (24), a dimmer Sun (28), the Man in the Moon (35), the oldest ash (46) the oldest uncontested(-ish) evidence for life (50), and the oldest rocks in the USA (55). While you wait for Season 3, check out patreon.com/bedrockpodcast for episodes of Hometown Geology, or bedrockpodcast.com for helpful scripts and images! Thanks for all the support!

Season 2 Finale! For 50 years, the title of "USA's Oldest Rock" was held on the prairies of western Minnesota. In 2025, that throne was usurped by a brand new study. Where is this "new" ancient location, what rocks are here, and how old are they? Stay tuned to find out! Dylan has an exciting announcement : he has a new visiting professor job at Gustavus Adolphus College in Minnesota! Thanks to everyone for their support. Speaking of which, if you want to donate: Monthly donations on Patreon One-off donations on Paypal

We finally end our great Greenland adventure with one final question: how did all these diverse rocks become squeezed together, 3.6 billion years ago? The answer to that question can tell us a lot about how the early Earth worked. According to some folks, plate tectonics was very similar to today. To others, Earth was a very alien world indeed. Along the way, we'll visit trenches off the coast of Japan, and turn our hands into tectonic plates. Dylan also has an exciting announcement : he has a new visiting professor job at Gustavus Adolphus College in Minnesota! Thanks to everyone for their support. Speaking of which, if you want to donate: Monthly donations on Patreon One-off donations on Paypal

At long last, we finish the cliffhanger from Episode 52! Last time, I introduced one of the greatest debates in paleontology and geology. Are a few little triangles on the Greenland tundra Earth's oldest visible fossils , or just some funny-looking rocks? Today, we'll discuss both sides like a court case, laying out a decade of debate. This has been an episode Dylan has waited a long, long time to produce! Click here to see images of the triangles! If you want to donate: Monthly donations on Patreon One-off donations on Paypal

Good news : After six months, my girlfriend's hospital odyssey is wrapping up for now. Bad news : My visiting professorship at GVSU has finally ended, and the job hunt continues. For better and for worse, I have more time to return to the podcasts. Bedrock and Hometown Geology will alternate on Wednesdays. The Brisbane episode of Hometown Geology will air June 24 for Patreon subscribers, and Episode 53 of Bedrock will air July 1. Thank you all for your patience once again, I'm excited to get behind the microphone again! If you want to donate: Monthly donations on Patreon One-off donations on Paypal

This brief update explains the long pause in episodes. A month ago, my girlfriend had a major, sudden hospital visit. The operation went smoothly, but there are many more hospital visits in the next few months. Episodes will return, but probably not until March. As always, thank you for your patience and well wishes! If you want to donate: One-off donations on Paypal Monthly donations on Patreon

Until now, all the clues for ancient life have been microscopic, beyond the realm of sight. Today, that begins to change. Ten years ago, a team of scientists showed the world a weird, lumpy rock that they claimed was the oldest microbial colony. Like a sci-fi movie, this specimen was found under melting ice in the high Arctic, unveiled from 3.7 billion years ago. But is it actually a fossil? Welcome to the debate that has defined my corner of geology. Extra Credit: Check your house for hard water damage, or watch The Thing (1982). Want bonus content? Check out the Patreon!

Here's a new monthly podcast that Dylan's releasing on Patreon! Hometown Geology focuses on cities/locations around the world, chosen by patrons. This pilot episode highlights Dylan's current hometown of Grand Rapids, MI, home of gypsum mines, coal forests, and mastodon skeletons. Want to hear next month's episode on Asuncion, Paraguay's capital, or to pick your own destination? Click here to sign up on Patreon!

This episode, we focus on just one special boulder from the Greenland tundra, a rock that might have Earth's oldest fossils. Over the past 10 years, scientists from around the world have used the latest technology to reveal this rock's secrets, including research published this year. What have they found? Extra Credit: Make a time capsule or play a record. Patreon for monthly donations One-off donations

Visit patreon.com/bedrockpodcast for bonus perks like new episodes, voting rights, and topic selection! P.S. Thanks to a bad cold, both my voice and the audio quality are not on par today. P.P.S. The cold has also delayed Episode 51, which will be up later this week.

Donate to support the show- anything is appreciated! Finally, 3.7 billion years ago, we reach some of the strongest evidence for life on Earth yet. It takes a while to find, and it only looks like a few dark crystals, but it's better than anything else we've seen so far. Along the way, we'll meet three scientists who helped define the quest for Earth's oldest fossils, including one of my old bosses. Extra Credit: Sharpen your pencils, spackle some cracks, or thank a mentor in your life.

In this casual chat, Dylan talks about the show's growth, the upcoming end of Season 2, a potential career shift to science communication, and other podcast recommendations. Thank you all for bringing this show to 50 episodes- here's to 50 more! Donate to support the show- anything is appreciated!

Many folks have claimed to find Earth's oldest fossils in the Greenland rocks, 3.7 billion years old. Before we meet and judge these contenders, we need to learn what counts as a fossil. This early in Earth history, nothing has any bones or teeth or shells, so researchers need to search for other clues. Today, I'll show you four ways to look for fossils in Earth's oldest rocks, including my personal field of study: fossilized bacteria. Extra Credit: Find different types of organic carbon in your day, or eat a burger.

What is the hardest rock to make? Today's rock is very common in Earth's ancient past, and it should be everywhere today. However, it's nearly impossible to form in nature or the laboratory. Some experiments have tried for 32 years with no success! This rock is dolomite. Today, we address The Dolomite Problem, one of geology's longest-running mysteries. Along the way, we'll meet some smelly but helpful bacteria, sort a fruit stand, and learn about the cutting edge of geology research. Extra Credit: Eat some citrus, and check your home for natural gas leaks.

Donate to support the show- anything is appreciated! Today is a tale of two sisters: limestone and dolomite. Limestone is far more popular and well-behaved, one of the most common stones in nature and in architecture. Dolomite, though similar in many ways, is one of the most difficult rocks to make on Earth. Even dolomite’s name is a bone of contention. Today, we introduce both siblings to the show as we move forward in time, 3.75 billion years ago. Along the way, I’ll give you a real experiment to try in the kitchen and we’ll smash some stones together. Extra Credit: Try today’s kitchen experiment, find some limestone around you, or get some calcium in your diet (dairy, leafy greens, or tofu).

What types of volcanoes were erupting 3.8 billion years ago? Today, we meet a new type of rock and a new type of volcano, far more powerful and dangerous than those we've met so far. The old volcano is long dead, but the scars it left behind can still be seen across the Greenland landscape. Along the way, we'll learn how different types of lavas are made, why a few rocks can float in water, and learn about a field trip Dylan took to Iceland in 2010. Extra Credit: Eat a grilled cheese sandwich, blow a bubble in gum, or make campfire.

What was Earth's mantle like 3.8 billion years ago, and how do we know? The mantle is a realm that humans have never visited, and examining it is only harder in the ancient past. Fortunately, the mantle sometimes gifts us with beautiful green rocks from the deep, souvenirs of an unknown underworld. Today, we learn how the mantle has changed over time, and its surprising connections to outer space. On the way, we'll meet the father of geochemistry, revisit old asteroid friends, and learn why you should always flour your berries before making a cake. Extra Credit: Bake some blueberry muffins. Donate to support the show- anything is appreciated!

What is the world's oldest slice of mantle, and how did it reach the surface? Today, we'll meet the first tangible piece of the world below the crust, a world humans still have not visited. Along the way, we'll meet an old mineral friend from Season 1, a researcher named Friend, and learn how diamonds can be a geologist's best friend when looking for slices of the mantle. Extra Credit: Clean your bathtub, or call an old friend. Donate to support the show- anything is appreciated!

In 1971, two geologists traveled to the edge of Greenland's ice sheet. What they found were the oldest rocks known at the time, 3.8-3.7 billion years old. Shockingly, they were in decent condition, sparking a half-century of geology stories. Today we'll begin our tour of Isua, the final destination of Season 2. Along the way, we'll meet a Holocaust survivor who landed on top of the world, visit an iron mine surrounded by glaciers, and start to meet the highest-quality rocks of this season. Extra Credit: Eat some candy, some shrimp, or some Indian food. Donate to support the show- anything is appreciated!