Adding a New (Holocene) Layer to our Sea Floor Model.
Our Core
'Drilling Our Core'
Next we did a core drilling experiment and agreed to believe that this represented the core we had headed to the Chatham Rise to drill on board The Aumoana. Ms Gain had created a sea floor model that had different layers, made up of cake slices and coloured playdough. Some of us took turns to add/deposit some new, recent layers to our sea floor to help us understand that the top layers in a core are the newest. We then used a long plastic tube to 'drill' a core sample. When the tube was lifted out we could see the different layers of our core. We talked about how the deepest layers of a core are the oldest and the top layers are the newest. We then looked at the Geological Time Scale and talked about how geologists can describe the different time periods the different layers are from. For example a layer of a core that is dated to 160 million years ago (done by testing fossils found in the layer) can be described as coming from the Jurassic period. The most recent material deposited on the sea floor today is described as being in the Holocene period. Some of our group has been researching how cores can tell us stories about the past, including the story of the KT boundary. In cores that have been drilled around the world there is a common layer of ash, which has been dated to 65 million years ago. This layer of ash, which seems to have covered the earth's surface, is thought to be evidence of an asteroid that hit the earth in the Gulf of Mexico 65 million years ago. It is thought that this event led to the extinction of dinosaurs, and in fact many creatures. There are many fossils found in layers below this ash layer that are not found above it.
