The 2015 Zircon Study vs. the 2016 Isthmus Review
Camilo Montes and colleagues dated zircons from an ancient South American streambed and concluded the continents connected before 13 million years ago. A year later, Aaron O'Dea's team published a comprehensive review defending the traditional ~2.8 million year isthmus, calling the earlier evidence inconclusive.
The field split into early-connection and late-isthmus camps.
The exchange sharpened the distinction between continental collision and the emergence of a land bridge.
The new magnetic study enters this unresolved debate, pushing the collision itself earlier while leaving the land-bridge question open.
