Stories from the Ocean Floor Developed by J Stories from the Ocean Floor Developed by J. Fechhelm using materials from the 2007 “School of Rock” sponsored by the Joint Oceanographic Institutions and the Integrated Ocean Drilling Program at Texas A&M University

The Deep Sea Drilling Project was begun in 1964 and was designed to investigate the evolution of ocean basins by core drilling of ocean sediments and underlying oceanic crust. The data used in this activity were taken from cores collected by the drill ship “Glomar Challenger”, on a cruise in 1968. The Deep Sea Drilling Project was the first of three international ocean drilling programs that have continued right up to today. http://pubs.usgs.gov/gip/dynamic/glomar.html Compare picture of the Glomar Challenger to posters /pictures of the Joides Resolution.

This map shows where the three ocean drilling programs have drilled into sediments on the seafloor and the Earth’s crust. Map showing drill sites http://iodp.tamu.edu/scienceops/maps/poster/combined.html

Remember that the plates on the surface of the Earth have changed position throughout the Earth’s history. These diagrams show what the Earth looked like 80 million years ago. http://jan.ucc.nau.edu/~rcb7/Late_Cret.jpg

When scientists drill into the sea floor, the oldest sediments are at the bottom, and the newest sediments, those that are just settling to the bottom of the ocean, are at the top. Map showing drill sites Illustration of core, section, and sample numbering. From: Shipboard Scientific Party, 2004. Explanatory Notes. In Tucholke, B.E., Sibuet, J.-C., Klaus, A., et al., Proc. ODP, Init. Repts., 210, 1–358.

On the third trip of the Glomar Challenger (Leg 3) the crew drilled holes at 10 different sites along an oceanic ridge between Africa and South America. What they found astonished many around the world and opened up a whole new area of scientific investigation. Personal story from J. Fechhelm: in 1968 I was in 8th grade and had a wonderful teacher who loved science, especially marine science. She and I would always talk about the latest Jacques Cousteau TV show! I can remember the day she told us about something she had heard on the news – and it was the information from the Glomar Challenger about the sea floor spreading apart. Point out to students that this was basically the start of the theory of plate tectonics. http://geology.wr.usgs.gov/parks/province/atlantpl.html

The numbers show the drill sites from Leg 3. The spots along A, B and C show drill sites along the Mid-Ocean Ridge.

When ocean cores are drilled, scientists can then look at the fossils of ancient organisms found in the sediments. From years of study, scientists can tell the age of sediments by looking at the fossils. Some organisms, or their fossils, are used as indicator species. This means that if those organisms are found, scientists can tell the age of the sediments, or when they were deposited on the sea floor.

Now back to Leg 3 of the Glomar Challenger! Let’s look at the actual data.

Let’s narrow our focus. Site Number Age of sediment above basement (in millions of years) 14 40 m.y. 15 24 m.y. 16 11 m.y. 17 33 m.y. 18 26 m.y. 19 49 m.y. 20 67 m.y. 21 >76 m.y.

Now let’s make a model of this and answer the rest of the questions. On your map, next to each site number, write the age of the sediments. (Remember, these sediments are those at the very bottom, right above the rock.) Answer questions 3, 4, and 5. Now let’s make a model of this and answer the rest of the questions. . At this point, end powerpoint and go to student sheet and make models (probably day 2). Afterwards, take a look at next slide and then allow students to work on or compare their answers to the diagram.