oceanic crust and sediment cover not shown to scale sediment cover Grades 8 -12 Eurasian Plate African Plate) (or One class period spreading based on their graphs. distance from the mid-Atlantic ridge. Draw conclusions about seafloor Draw conclusions about seafloor Interpret data of sediment age and Interpret data of sediment age and Graph this data. • National Science Education Standards A: Science as Inquiry Standard Standard D: Earth and Space Sciences of Science Standard G: History and Nature Age: Target Time: Materials Graph paper ocean drilling were still in their infancies. ocean drilling were of drill sites on the Compare the number (Figure 2) to that of today sea floor in 1969 (Figure 3). Learning Objectives Students will be able to: • •

central rift valley distance from ridge (in km) Mid-Atlantic Ridge age of crust (in millions of years) magma chamber N. Amer. Plate Amer. N. Plate) Amer. (or S. Going Back to the Original Data: Original Back to the Going 80 60 40 20 0 20 40 60 80 Scientific Ocean Drilling Ocean Scientific 2400 1800 1200 600 0 600 1200 1800 2400 MOHO Figure 1. Relationship between ridge axis and seafloor age redrawn from Leckie and Yuretich (2003). Yuretich Figure 1. Relationship between ridge axis and seafloor age redrawn from Leckie and oceanic crust Senegal to Brazil, December 1968 to January 1969 Brazil, December 1968 Senegal to Results from Deep Sea Drilling Project (DSDP) Leg 3 Deep Sea Drilling Project Results from and Contributions from from Contributions and Tectonics Plate ocean drilling played a critical defining ocean drilling played a critical defining role in the development of the theory Leg 3 of plate tectonics, and DSDP age provided definitive proof of seafloor mid- relationships with respect to the Leg 3 sailed oceanic ridge. When DSDP in 1969, plate tectonics and scientific Background are probably familiar with standard You textbook figures showing the relationship age (see between ridge axis and sea floor Figure 1). The theory of plate tectonics is an theory established, accepted foundational the initial of earth science. But what were the discoveries or observations about to seafloor that were key contributions Scientific the development of this theory? Summary data from an early Students use original of scientific ocean drilling leg in the history the excitement of original to participate in data. discovery from authentic

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Initial Reports of DSDP, Initial Reports of DSDP, . and the small brown m www.deepseadrilling.org/03/ , Leg 3 was essential ground truth needed truth needed essential ground Leg 3 was hypothesis. to test the at each of basement rocks The basaltic at originated (crystallized) these sites moved to their and have since the ridge location on the adjacent present geographic of Hypothesize why the ages sea floor. basement also show sediment overlying from the ridge. increasing age away Atlantic in the South seafloor spreading your age- 1 or Table using the data from that: Rate = Distance/ distance plots. (Note Time. Leg 3 scientists by with that of the DSDP reading the original text and age-depth graph from the III Volume dsdp_toc.ht This age vs. distance data from DSDP DSDP data from distance age vs. This rate (cm/yr) of Calculate the average can check your scientific reasoning You Glomar Challenger c. d. e. 2 dots indicate drill sites. At this point (January 1969) scientific ocean drilling was still in its infancy. 1969) scientific ocean drilling was still in its infancy. At this point (January dots indicate drill sites. Compare it to the 2006 map of drilled site locations (Figure 3). Figure 2. The light brown line marks the ship track of the The Figure 2.

from the ridge axis? of basement rock and distance from ridge of basement rock and distance from axis? distance sediment overlying basement and from ridge axis. ridge axis. What is the relationship between the age What is the relationship between the age of What is the relationship between Basement (paleomagnetic) age vs. distance vs. age (paleomagnetic) Basement from Bottom sediment age vs. distance a. b. a. b. age of sediment above basement for the age of sediment ages These map. Leg 3 sites on the DSDP by Leg 3 scientists based were determined and biostratigraphic on magnetostratigraphic principles. DSDP Leg 3 drilling locations and the position locations and Leg 3 drilling DSDP ridge (Figure Atlantic mid-ocean of the South table of data (Table accompanying 4) and the age both the magnetic This table shows 1). the paleontological rock and of the basement Based on your graph(s), answer the following: Based on your graph(s), answer Plot on graph paper: Familiarize yourself with the map showing the the map showing with the yourself Familiarize 3. 2. Activities and Questions and Activities 1.

Plate Tectonics and Contributions from Scientific Ocean Drilling Teaching for Science • Learning for LifeTM | www.oceanleadership.org 60° EUROPE 30°E ). AFRICA l 0° OCEAN TLANTIC A 30°W SOUTH GREENLAND AMERICA 60° 90° TH http://iodp.tamu.edu/scienceops/maps.htm NOR AMERICA 3 120° Expeditions 301–312 ( ) ACIFIC OCEAN OCEAN P SOUTHERN 150°W ARCTIC OCEAN 180° Legs 100–210 ( ), IODP 150°E 150° AUSTRALIA 120° Exercise by Kristen St. John ([email protected]) and Mark Leckie ([email protected]), Exercise by Kristen St. John ([email protected]) and Mark Leckie ([email protected]), 120°E ASIA 88°00ʼ N 87°30ʼ ARCTICA ANT 90°E Legs 1–96 ( ), ODP Adapted from School of Rock materials by St. John and Leckie, 2005 for the GSA Annual Meeting 2006, Philadelphia, PA Adapted from School of Rock materials by St. John and Leckie, 2005 for the GSA INDIAN OCEAN DSDP Figure 3. Combined IODP, ODP, and DSDP Sites, October 2006 (from and DSDP ODP, Figure 3. Combined IODP, 60° S 20° 40° 40° 20° 60° 80° N 0°

Plate Tectonics and Contributions from Scientific Ocean Drilling Teaching for Science • Learning for LifeTM | www.oceanleadership.org 10 10 10 20 20 20 20 10 + + + + + + + + 221 422 506 718 745 1303 1686 1010 Rotation at 62°N, 36°W 20 20 5 10 20 20 10 10 + + + + + + + + Distance from ridge axis (km) Linear 191 380 506 643 727 990 1270 1617 (1968). , p. 461) 1 1 1 2 1.5 1 1 et al. + + + + + + + , p. 460). >76 (m.y.) 11 11 67 24 26 33 49 40 Age Sediment Paleontological a Above Basement 4 TABLE 5 TABLE a a 9 21 53 --- 70-72 38-39 (m.y.) 34-38 Age of Magnetic Basement Deep Sea Drilling Project, Volume III Deep Sea Drilling Project, Volume Distances of Mid-Atlantic Ridge Sites from the Axis the Distances of Mid-Atlantic Ridge Sites from Magnetic Anomaly Numbers and Ages, Paleontological Ages, and Ages, Paleontological Anomaly Numbers and Magnetic 6 5 ------21 30 No. 13-14 Initial Reports of the Deep Sea Drilling Project, Volume III Initial Reports of the Deep Sea Drilling Project, Volume Magnetic Anomaly Magnetic Figure 4. Location of DSDP Leg 3 sites relative to the axis of the Mid-Atlantic Ridge (from Figure 7 in the Leg 3 sites relative to the Figure 4. Location of DSDP Initial Reports of the c 17 14 19 20 16 15 18 21 Location of these sites without the characteristic magnetic anomaly pattern is uncertain. The number of the magnetic anomaly and its age has been taken from Hertzler, The number of the magnetic anomaly and its age has been taken from Hertzler, Basement rock not reached at Site 21. a b c (From Table 5, Table (From Table 1. Magnetic anomaly number and ages, paleontologial ages, and distances of Mid-Atlantic Ridge sites from the axis. 1. Magnetic anomaly number and ages, paleontologial ages, and distances of Mid-Atlantic Ridge sites Table Site No.

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