Randall Irmis, curator of paleontology at the Natural History
Museum of Utah and assistant professor at the University of
Utah, is investigating the rise of dinosaurs in southeastern
Utah. Friday, Sept. 7 It is often said that geological and
paleontological investigations are like trying to put together a
puzzle with many of the pieces missing. Yet, while we can’t
travel back in time to observe every detail, the geologic record
contains a rich archive of past life and its environments. As
I’ve mentioned in previous posts, we’re interested in not only
in the animals and plants that lived 210 million years ago, but
also their physical and climatic surroundings. The rocks we’re
working in contain many clues to this past environment, if you
just know where to look. Even the color is important; in our
area, the lower part of the Chinle Formation is greenish-gray,
whereas the younger Chinle rocks are orange and red. All of
these sediments contain trace amounts of iron. When iron
oxidizes, or rusts, it typically tur