One of my favorite places to hike in the Billings area is Zimmerman Park, which is mostly atop the Rimrocks, a cliff formed by sandstone of the Cretaceous Eagle Formation. The Eagle Formation is usually interpreted to be either a barrier island deposit, similar to Padre Island in Texas, or a shallow marine sand bar …
Tag: Cretaceous
Billings Gazette geology videos
The Billings Gazette has three short videos on the geology of the Billings, Montana area featuring Rocky Mountain College geology professor Derek Sjostrom: Geology of the Beartooths -- Montana's highest mountain range (Granite Peak, 12799 ft, 3902 m) has a core of 3.2 billion year old metamorphic rocks. Geology of the Pryors -- The Pryor …
K-T iridium layer, Raton NM
The first concrete evidence that an asteroid impact ended the Cretaceous Period was the discovery of an iridium-rich layer marking the Cretaceous-Tertiary (K-T) boundary by a team led by Luis Alvarez in the early 1980s. Iridium is very rare in Earth's crust, but is considerably more abundant in asteroids, leading geologists to conclude that the …
K-T boundary
From NASA's Earth Observatory: Raven Ridge, Colorado. This ridge, south of Dinosaur, Colorado, apparently has an exposure of the K-T (Cretaceous-Tertiary) boundary, which marks whatever event ended the age of dinosaurs (asteroid? volcanism? the real reason dinosaurs went extinct?). This gives me two places within a day's drive to visit the K-T boundary, the other …
GeoChristian 