Figured I might as well start this. For those who don't already know, this year's topic is Tectonics.
1. What are the layers of the ophiolite suite?
2. If an ophiolite is found near a coastline, what tectonic processes is this indicative of?
Re: Dynamic Planet B/C
Posted: September 6th, 2016, 8:38 pm
by bhavjain
Unome wrote:Figured I might as well start this. For those who don't already know, this year's topic is Tectonics.
1. What are the layers of the ophiolite suite?
2. If an ophiolite is found near a coastline, what tectonic processes is this indicative of?
1. From least deep to most deep: sediments, pillow lava (basalt), sheeted dykes, gabbro, and peridotite.
2. Obduction at a convergent plate boundary.
Re: Dynamic Planet B/C
Posted: September 7th, 2016, 6:25 am
by Unome
Correct, your turn!
Re: Dynamic Planet B/C
Posted: September 7th, 2016, 8:24 am
by bhavjain
What is the smallest tectonic plate? Biggest? (Must be major or minor plates)
Re: Dynamic Planet B/C
Posted: September 9th, 2016, 9:11 am
by chscioly
Smallest plate-Scotia Plate
Largest plate-Pacific Plate
I haven't been able to find a clear definition of major and minor plates. It seems like different sources are defining them based on different area requirements.
Re: Dynamic Planet B/C
Posted: September 9th, 2016, 9:23 am
by Unome
chscioly wrote:
Smallest plate-Scotia Plate
Largest plate-Pacific Plate
I haven't been able to find a clear definition of major and minor plates. It seems like different sources are defining them based on different area requirements.
I've found the same thing. Generally I rely on definitions provided on websites for college courses or in commonly-used textbooks, as that is what event supervisors tend to use.
Re: Dynamic Planet B/C
Posted: September 9th, 2016, 12:02 pm
by bhavjain
chscioly wrote:
Smallest plate-Scotia Plate
Largest plate-Pacific Plate
I haven't been able to find a clear definition of major and minor plates. It seems like different sources are defining them based on different area requirements.
Correct. Wikipedia lists two more smaller minor plates, but all my other sources list Scotia as the smallest microplate.
Re: Dynamic Planet B/C
Posted: September 10th, 2016, 10:42 am
by chscioly
Give three pieces of evidence supporting continental drift.
Re: Dynamic Planet B/C
Posted: September 10th, 2016, 10:54 am
by Unome
1. The presence of similarly layered/formed rock formations on many southern continents (iirc the Karoo supergroup is a major example).
2. Magnetic polarity changes in older rocks, especially those that have rotated due to continental drift, or those that have been reversed along seafloor spreading axes.
3. The abundance of similar fossil flora and fauna on many southern continents that presumably could not have crossed the oceans, implying that there once existed a land-based connection between the continents.