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Science and Ideas Group: Plate Tectonics: A Revolution in Earth Science

Wednesday, March 10, 2021, 3:00 PM until 4:30 PM
Join Zoom Meeting : See below.

Additional Info:
Roger C Newman
Interest Group
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Payment In Full In Advance Only
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RSVP:  Roger Newman (

When: Every 2nd Wednesday of the month, 3:00-4:30 pm

Where: Zoom -  link tba

Open to: All

Plate Tectonics: A Revolution in Earth Science

This presentation begins with a history of plate tectonics, also known as continental drift. Before the Second World War, belief in continental drift was largely limited to geologists who worked in the Southern Hemisphere. The availability of surplus magnetometers after the war changed that by producing a large volume of supporting evidence and by 1970 the theory was widely accepted. After that, the components of plate tectonic theory will be summarized, including the three types of boundaries, the thickness of the moving plates and deeper features known as hot spots. The last part of the presentation will focus on ongoing research topics; what happens to downgoing slabs, the driving mechanism of Atlantic opening and plate tectonic cycles earlier in Earth history.

Greg Croft is an independent petroleum consultant and a lecturer in Environmental and Earth Science at Saint Mary’s College in Moraga, California. He holds a PhD in Civil and Environmental Engineering from UC Berkeley, an MS in geophysics from Stanford and a BA in geology from UC Santa Barbara. Dr. Croft has more than 30 years’ experience in oil and gas exploration and production and is a frequent public speaker on energy issues and geology.

This graphic and story from the Feb. 6 NY Times should prepare attendees.
Watch This Billion-Year Journey of Earth’s Tectonic Plates
(A new simulation offers a different view of how the continents we live on drifted into their current configuration.)