Students went on a field trip to Kalodir, a site where with exposed sediments that are over 17 million years old. After chipping away sediments students recovered impressions of leaves and other plant parts. Impressions occur when, let’s say a leaf, drifts to the lake bottom where it is covered with fine sediments such as clay and silt. Over time the water disappeared and the sediments around the leaf hardened. Even though the organic matter that made up the leaf decomposes, the leaf left an in-print behind. This “impression” is what students found. Sometimes, and under certain conditions, plant parts do not decomposes but are preserved. This type of fossil is called a “compression”.
A impression of a plant from 17 million years ago!
Devora is chipping away at sediment at Kalodir to remove a block of plant fossils
Marcela is preparing (cleaning) one of the leaf fossils she found.
Cleaning hard sediment off the leaf impression - its precision work and requires a steady hand.
Instructor Dr. Bonnie Jacobs is showing Bean how to prepare the fossil with the help of a tool.
While some students prepared their plant fossils, others were engaged in other tasks. For example, piecing together tiny rodent skulls! One way to figure out what species of rats and mice live in an area is to rely on their predators – or better, what they leave behind. Owls, for example, regurgitate the fur and bones of their prey and spit it out in pellets. These “hairballs” are soaked in water and one can extract all the bones. Each rodent species is of a different size, shape, and may vary with regards to tooth shape, which allows the reconstruction of the prey.
Devora and Michelle are sorting through piles of rodents skulls.
Rodent crania viewed from "below" (looking at the palate) - note the tiny teeth.
