Sea Floor Spreading Seafloor Spreading 1 Midocean ridges

Sea Floor Spreading

Sea-floor Spreading 1. Mid-ocean ridges (MOR)- sea floor spreads & new ocean floor creates underwater mountain chains

Mid-Ocean Ridges

What Changed and Evidence for Sea Floor Spreading Late 1950’s began mapping the ocean bottoms Sonar, gravity and magnetics Magnetic data provided corroboration of sea floor spreading Appeared to be striped Polarity reversal were identical on each side of oceanic ridge A relationship between earthquakes and plate boundaries 1960, Harry Hess proposes sea-floor spreading Confirmed by mini-Submarine Alvin in 1960’s

Magnetic Reversals

Final Proof 1968 United State Geologic Survey (USGS) Deep sea drilling w/ Glomar Challenger Drilling verified the age correlation in ocean floor rocks. Where do you think the oldest rocks are located on the sea floor? Youngest?

Video on sea-floor spreading MOR-New ocean crust Subduction Melting Asthenosphere

What's happening at the other end of the sea floor spreading centers? 3. Subduction- process of the ocean floor sinking back into mantle a. Deep-ocean trenches- deep water canyons in ocean

Review of subduction zone

Sea Floor Spreading Lab Sea-floor spreading lab Textbook: Pg. 148 - 149 Answer Analyze & Conclude Questions: 1 -6 on loose leaf paper and staple it to front of the model of sea-floor spreading.