Fault Lines

At the end of the Permian, about 252 million years ago, Earth was a hot, low-oxygen world in which most of the living ocean and a large share of land animals were dying out. This episode of Fault Lines asks what actually caused the end-Permian mass extinction, treating the question as a trial with three suspects: Siberian Traps volcanism, ocean heating and suffocation, and a string of unrelated re...

Sixty-six million years ago, at the end of the Cretaceous, a roughly ten-kilometer-wide rock struck the Yucatán while massive volcanic eruptions were already reshaping the Deccan region of India. This episode of Fault Lines asks not only what caused the mass extinction but how fast the killing happened: in hours, over decades, or across millennia. The hosts compare three clocks: a possible firesto...

About 201 million years ago, at the end of the Triassic Period, ferns spread across a smoky, overheated land while the oceans were already short of oxygen. This episode of Fault Lines asks what drove the end-Triassic extinction: a fast, sulfur-driven blow, a slow suffocation, or both. Ola and Amara weigh three 2026 clues against one another: sulfur released by magma that stayed underground, eviden...

About 539 million years ago, the seafloor was home to soft-bodied organisms in shallow seas, just before shelled animals, spines, and eyes appear in the fossil record of the Cambrian period. Was the so-called Cambrian explosion a real burst of evolution, or an artifact of which animals fossilize? Hosts Amara and Ola weigh the evidence, including the Jiangchuan Biota from China, a molecular-clock s...

About 4,500 million years ago, during the Hadean Eon, Earth was a glowing, partly molten ball of rock when a Mars-sized body called Theia struck it. The episode asks whether new simulations showing a Moon-sized body forming in about five hours overturn the giant impact story or simply add a conditional branch to it. Topics include the September 2026 simulations that add rock strength and test thre...

Before the Great Oxidation Event, roughly 2,450 million years ago in the Paleoproterozoic era, Earth had an orange, hazy sky, sulfur-rich air unfit to breathe, and oceans tinted purple by dissolved iron. This episode asks how firm the textbook version of that transformation really is, and how much oxygen actually accumulated. Discussion covers a 2026 University of Victoria study linking a carbon-1...

Roughly 200 million years ago, during the late Triassic, Earth's landmasses were locked together in the single supercontinent Pangaea; a billion years earlier, an even older supercontinent called Rodinia had already formed and broken apart. This episode traces how scientists went from denying continents move at all to debating how many times supercontinents have assembled and split. It covers Alfr...

Roughly 717 million years ago, Earth's tropics vanished beneath ice kilometers thick, transforming the planet into a near-total snowball during the Cryogenian period. This episode asks how the Sturtian glaciation could have lasted 56 million years without breaking, a duration that initially defied standard climate models. Discussion covers the Harvard-led carbon-cycle mechanism involving basalt we...

A narrow Himalayan valley on the Nepal-Tibet border, quiet enough to hear a yak bell, is erased in minutes when a wall of mud, ice, and bedrock breaks loose from Langtang Lirung and travels nearly one hundred kilometers. This episode asks whether a 2026 glacial lake outburst flood follows the same mechanics as the deep-time megafloods the show usually reconstructs from rock layers, like the Ice Ag...

Fifty million years ago, during the Eocene, Earth was a warmer world with crocodiles near the poles and a magnetic field that was anything but calm. This episode asks whether the geological record of geomagnetic reversals is actually complete, or if entire flips of Earth’s magnetic field are missing from the story scientists tell. Along the way, the hosts examine ultra-slow reversals lasting up to...

On March 28, 2025, a security camera outside Mandalay recorded the ground itself tearing sideways, 2.5 meters of slip along Myanmar's Sagaing fault in roughly two seconds, the same fault system born from the India-Eurasia collision some 50 million years ago. This episode asks whether fault rupture is governed by predictable physics or reconstructed after the fact through hindsight. Ola and Amara u...

252 million years ago, Pangaea sat surrounded by a single vast ocean where tropical surface waters climbed past 38-40°C and oxygen levels collapsed, setting the stage for the Permian-Triassic extinction. This episode of Fault Lines puts a new study claiming to have "solved" the Great Dying on trial, asking whether one explanation can really account for a catastrophe that killed 96% of marine speci...

Four minutes after the Chicxulub asteroid struck the Yucatán roughly 66 million years ago, at the end of the Cretaceous period, the sky over the Gulf of Mexico turned white-hot as vaporized rock rained back down as glass spherules, triggering a global heat pulse. This episode asks what actually killed life across the planet in the hours, weeks, and months that followed. Ola and Amara examine a new...

Around 66 million years ago, at the close of the Cretaceous period, a shallow sea covered the Yucatán Peninsula moments before an asteroid strike wiped out most life on Earth. This episode asks how scientists can identify the composition of an impactor that vaporized on contact, leaving no physical fragments behind. Ola and Amara walk through the nickel isotope technique used on K-Pg boundary clay...

Roughly four billion years ago, during the Hadean and early Archean, Earth's crust was a patchwork of newly stabilized blocks whose tectonic behavior remains debated among geochemists. Recorded live at Goldschmidt 2026 in Montréal, this episode asks whether plate tectonics began as one clean global shift or emerged unevenly across different regions and times. Ola and Amara compare zircon evidence...

Amara opens with a cinematic tour of the 520-million-year-old Xiannüdong reef in Shaanxi, China, where hot Cambrian seas hosted nearly every major animal group — except one conspicuously absent group of filter-feeders. In this episode, we cover Scene-setting / cold open, Background / mystery setup, Core science / the discovery, and more.

Three hundred and nine million years ago, the land beneath modern Chicago was a swampy equatorial delta — oxygen at 35%, club mosses thirty meters tall, and dragonflies the size of hawks. The central question of this episode: did early four-legged vertebrates develop through amphibian-style metamorphosis, or did they hatch as miniature adults from the start? Ola and Amara examine the Pardo and Man...

Sixty-six million years ago, in the Late Cretaceous, foraminifera-filled oceans teemed beneath skies that had never seen a mass extinction — until a 10-kilometer asteroid ended that world in seconds. This episode of Fault Lines asks whether the Chicxulub impact was purely a catastrophe, or whether it also structured what came next. Ola and Amara examine a June 2026 study in Communications Earth an...

On June 15, 1991, the sky over Central Luzon turned white as Mount Pinatubo sent an ash column 40 kilometres into the stratosphere. The central question this episode tackles is whether the canonical 0.5 degrees Celsius of global cooling attributed to Pinatubo is actually reliable — and what is at stake if it is not. Ola and Amara trace the mechanism of stratospheric aerosol forcing from Pinatubo's...

Seven hundred and seventeen million years ago, the equator was buried under sheets of ice in what geologists call the Sturtian glaciation, a freeze that lasted 56 million years. This episode asks a single question: was Snowball Earth a static, locked prison, or something far more dynamic? Ola and Amara examine two competing answers from the Cryogenian period (approximately 717 to 660 million years...

Sixty-six million years ago, Earth was a greenhouse world with no polar ice, CO2 above 800 ppm, and palm trees growing in Alaska. This episode of Fault Lines asks why all that warmth slowly disappeared over the following 50 million years of the Cenozoic era. Ola and Amara examine a University of Southampton PNAS study finding that seawater calcium dropped by more than half across that period, walk...

On May 18, 1980, a magnitude-5.1 earthquake stripped the entire north face of Mount St. Helens in seconds, releasing the largest debris avalanche in recorded history. The episode asks whether the monitoring revolution that followed actually prepares us for the volcanic events capable of ending mass life on Earth. Ola and Amara move from the 4.2 cubic kilometers ejected at St. Helens up to the Sibe...

Two hundred and fifty-two million years ago, a biologically stable marine world built over fifty million years was erased in geological near-silence. This episode of Fault Lines examines the central question of the Permian-Triassic extinction: what actually killed 96% of marine species, and did anything that followed deserve to be called recovery? Ola and Amara walk through the Siberian Traps as t...