This is the first episode in a series of 3 on the world's longest cave system - Mammoth Cave in Kentucky.  In this episode, Chris and Jesse talk a little about Mammoth and some of its impressive statistics.  The focus however, is more about the necessary ingredients for cave development in general.  We talk about the 4 general ingredients: suitable rock type, a solvent, hydraulic gradient, and time.  We also go into some detail on what each of these really mean.  We hope you enjoy.  In the next episode in this series, we'll talk about Mammoth specifics. We now hav ..read more

In this episode, Jesse and Chris talk about the geology of Iceland - although we keep it at a high level.  We're going to come back to this - Iceland - later after Chris returns from his trip.  Then, we'll get into some of detail that makes Iceland so unique.  Here, we discuss how Iceland might be a prototype for the formation of continents and also talk a bit about the diversity of igneous rocks that make up the Island.  The diversity of rocks speaks to the diversity of volcanic activity.  We finish up the episode with a short discussion about what Chris is most looki ..read more

Hardpan!  Where did this idea for an episode come from?  Chris has  been doing a ton of yard work lately and it’s not uncommon come across a layer when digging a hole that is next to impossible to penetrate. He has to bust out my pick axe to get through it.  It's  Called Hardpan. Really dense layer that often occurs below the topsoil.   Problems: Roots can’t penetrate into the hardpan (Hayden Valley in YNP).  Trees are easily blown over if they can even grow here. Water can’t penetrate so the soil layer above is easily saturated. Safe to say that farmers an ..read more

Today we really go into the weeds. Jesse and a colleague just published a paper in the journal Nature that proposes a new model for how continents became stable. Stable continents have all the granite at the surface, which contains all the heat producing elements like U and Th and K - elements that decay away. Today, we discuss that paper in detail, and along the way learn a bit about the early Earth, what we know and don't know! Here is a link to the paper, which is open access and can be downloaded by anyone without paying.  We now have a live Mobile App for iOS and Android. There yo ..read more

Today, Chris and Jesse get into a discussion about Earth’s oldest material.  Earth is 4.568 Billion years old.  First of all, that’s amazing the geochronologists have refined this down to 3 decimal places.  How do we know this?  The oldest grains ever found are 4.38 billion years old.  If that’s the case, then how do we know the Earth is significantly older than that?  Join us as we answer that and many other important questions about Earth’s oldest stuff.   We now have a live Mobile App for iOS and Android. There you can learn all the basics of geoscience w ..read more

In this episode, we tackle a listener question regarding planning a geology trip for students.  Both Chris and Jesse have quite a bit of experience in planning and executing field excursions for students.  We believe that seeing geology in the field is one of the most powerful learning opportunities for students of all levels.  In our discussion, we talk about the difficulties in convincing the higher-ups that this is actually a good idea.  We also get into some of the struggles in finding excellent teacher resources.  In the end, we get a little philosophical on the i ..read more

We now have a live Mobile App for iOS and Android. There you can learn all the basics of geoscience with our CampGeo content, purchase a visual audiobook on the Geology of Yellowstone National Park, and listen to past PlanetGeo episodes! Download now at this link Like, Subscribe, and leave us a Rating! —————————————————— Instagram: @planetgeocast Twitter: @planetgeocast Facebook: @planetgeocast Support us: https://planetgeocast.com/support-us Email: planetgeocast@gmail.com Website: https://planetgeocast.com ..read more

Join us as we have the honor of interviewing Dr. John Douglas.  Jesse and Chris have been following his research on how the Grand Canyon was actually formed for some time.  We have recently finished our audio-visual book on the Grand Canyon (Link above) and we have a chapter dedicated to the actual cutting of the Canyon.  The answer to this question has been elusive, but there are a few leading theories.  John has been leading the way on the Spillover Theory as a mechanism for carving the young Canyon.  It's a great geologic discussion and we hope you enjoy. We now hav ..read more

In charge of the Nations Rock Collection.  That's a pretty sweet job description.  Join us as we have the honor of interviewing Dr. Mike Ackerson.  In this episode, we certainly get into some detail about igneous petrology.  Mike and Jesse are good friends and have spent some time discussing things that introductory geology classes take for granted.  For instance, there are some questions on the formation of granite.  This might seem ridiculous because this topic is covered in any intro level geology class, but there are some problems. We also talk philosophicall ..read more

Today, Jesse and Chris discuss the geology of Nickel - The Devil’s Metal.  Surprisingly, Earth’s core has a high percentage of Nickel - 10 to 20% of the core is nickel.  We allow ourselves the luxury of getting into the details on nickel and why the core has so much.  Of all the metals we’ve discussed on the podcast, the geology of nickel is the most complicated.  In addition to discussing the geologic settings that form or concentrate nickel, we also spend some time discussing the history and uses.  We hope you enjoy the discussion. We now have a live Mobile App for i ..read more