The Room Problem (and how Geochronology solves it)

PlanetGeo: The Geology Podcast · Jul 2, 2026 · 54m · transcript

Granite is everywhere — it makes up much of the continental crust beneath our feet; yet, for over a century geologists were stuck on a deceptively simple question: where does all that magma find room? In this episode, Jesse and Dr. Mike Ackerson pick the granite series back up to tackle the "room problem" — the puzzle of how you wedge a magma body tens of kilometers wide into solid crust. Using California's Tuolumne Intrusive Suite (the fruit fly of igneous petrology) and the landmark Coleman et al. 2004 paper, they show that the way out isn't space at all — it's time. These giant plutons…