August 15, 2006 - Making Sense of Mud and Silt, The work of a sedimentologist Options

[Jason_Petula]

Today I headed off with Dr. Paul McCarthy (University of Alaska – Fairbanks) to investigate the sediments making up the bluffs comprising the dinosaur bones. Finding dinosaur bones in rock is exciting, but it can only provide so much information. For example, certain bone characteristics may identify a fossil as a hydrosaur (i.e. – duck billed dinosaur). But what about the environment these dinosaurs lived in? How did they die?

Paul and graduate students Peter Flaig and Doloris a van derKolk are investigating the sediments forming the beautiful bluffs of the Colville River. Making sense of these ancient layers requires careful observation and notation. Paul explained that the sediment types found in this area are indicative of a large meandering river system. He hands me some sand and enthusiastically states, “That is sand from the days of the dinosaurs.”

Paul reads the sediment layers to reconstruct what the environment was like 65-70 million years ago. He can tell when an area flooded and how an ancient river channel changed course. One layer we analyzed contained vast quantities of coalified wood. Some of the pieces were very large in diameter, suggesting a much warmer climate in the past because tree size is somewhat dependant upon temperature. For instance, most of the trees I see around me are no taller than an average adult. Before this morning, I would never have imaged so much sense can be made from mud and silt.


Mike Tapp displays some beautiful cretaceous wood.