Unit 11 – Living on Earth I: Evolution and Extinction

Dinosaurs: Where They Lived, and How They Died

Photos by R. Alley or as indicated.

The Green River in Dinosaur National Monument

Unit 11 – Living on Earth I: Evolution and Extinction

The river-channel and floodplain deposits of the Jurassic (mid-Mesozoic, about 150 million years old) Morrison Formation of Dinosaur National Monument, Colorado and Utah, were tipped up after being hardened.

Unit 11 – Living on Earth I: Evolution and Extinction

The Quarry at Dinosaur Ledge. Eleven types of dinosaurs were washed onto this sand bar perhaps in a great flood, buried, and their bones replaced by silica from groundwaters. The living types were quite different from their older relatives at Petrified Forest; much evolution occurred during the intervening 60 million years.

Unit 11 – Living on Earth I: Evolution and Extinction

Four views of the Quarry at Dinosaur Ledge. Ranger in lower left for scale. Some of those dinosaurs were big!

Unit 11 – Living on Earth I: Evolution and Extinction

D. Roddy, Lunar and Planetary Institute, NASA, http://antwrp.gsfc.nasa.gov/apod/ap971117.html

The 49,000-year-old, 0.7-mile-across Barringer Impact Crater of Arizona was made by a rather small meteorite, roughly 150 feet (50 m) across--tiny compared to the one that killed the dinosaurs. Notice the road on the right for scale.

Unit 11 – Living on Earth I: Evolution and Extinction

Above: Gravity field of Chicxulub impact crater--the meteorite that killed the dinosaurs, on the Yucatan Peninsula. The crater is buried under younger rocks, but is quite evident here. The circular crater, between the pink arrows, is about 110 miles across.

Below: Shocked quartz from a meteorite impact. The bright colors are from view between polarizing filters; the crossing lines are impact features. The grain is roughly 1/10 inch across.

All pictures on this page from NASA http://rst.gsfc.nasa.gov/Sect18/Sect18_4.html

Left: Impact breccia. When a meteorite hits, it breaks rocks. This core is from the Manson, Iowa impact structure.

Unit 11 – Living on Earth I: Evolution and Extinction

Timothy Culler (UCB) et al., Apollo 11 Crew, NASAhttp://antwrp.gsfc.nasa.gov/apod/ap000322.html

(Above) 1/250 in (0.1 mm) diameter cosmic spherule from the moon. Spherules such as this are well-known from impact deposits, and are found in the special K/T impact bed that marks the end of the dinosaurs.

(Below) The finger is pointing to the K/T boundary bed marking the end of the dinosaurs, at Big Bend National Park.

National Park Service Photo http://www2.nature.nps.gov/geology/geologic_wonder

s/images/KT.jpg

Unit 11 – Living on Earth I: Evolution and Extinction

Richard D. Norris and the Ocean Drilling Project Leg 171B Scientific Party

http://www.usssp-iodp.org/Publications/Greatest_Hits/contributors.html#n

Photomicrographs by Brian Huber, Smithsonian Institution. Low-res. versions are hosted at: http://www.usssp-iodp.org/Education/resources.html

More information: http://www.nmnh.si.edu/paleo/blast

Sediment core from offshore South Carolina, showing the extinction across the K/T boundary. Core is 40 cm long (about 16 inches).