Using the power of Google Earth, GeoTours take you on flyovers of key locations discussed in the text.
StudySpace student website and ebook icons in each GeoTour connect your to the text and online review materials.
Dialogue boxes accompanying each site include text, figures, photos.
|
|
Geotour 7: Precambrian Metamorphic Terranes
Zones of Metamorphic Grade
|
| 1a. In the Problem 1 folder, turn on the “New England Metamorphic Zones” map overlay (double-click it to fly to the area).
If you traveled north from placemark Problem 1a, would you go into higher or lower metamorphic grade rocks?
|
|
|
| 1b. Based on your answer to (a), would the metamorphic core of this region be near placemark Problem 1b-i or 1b-ii?
|
|
|
| 1c. For the schist pictured in placemark Problem 1c, which zone did it likely occur in (look at the red minerals)?
|
|
|
Type of Metamorphism
|
| 2a. For this problem, you will compare and contrast the metamorphic area depicted in Problem 1 with an area in the Henry Mountains of Utah.
Referring to the area covered by the “New England Metamorphic Zones” map overlay in Problem 1, what type of metamorphism likely produced these metamorphic rocks?
|
|
|
| 2b. Check and double-click placemark Problem 2b to fly to the Henry Mountains in Utah. What type of metamorphism likely produced the thin, white bleaching of the reddish sandstone in this area? Hint: You may want to fly around this area to look at the features present.
|
|
|
| 2c. Check and double-click the Van Hise Rock, WI photo overlay in the Problem 2 folder to fly to the Rock Springs, WI area to view a zoomable photo of the outcrop. These Precambrian rocks experienced greenschist grade metamorphism as the rock layers were buried and then subsequently folded and sheared past each other. Which of the three choices below best describes the type of metamorphism that these rocks experienced?
|
|
|
| 2d. The protolith of the pink/maroon rock was a pure quartz sandstone, whereas the darker layer was originally a lens of clay-rich shale. What metamorphic rocks did these protoliths (sandstone, shale) become?
|
|
|
Metamorphism: Past & Present
|
| 3a. Check the box next to “Global Map of Shields & Mt Belts” in the Problem 3 folder to view the Precambrian shields (maroon) and the younger mountain belts (green). Also, in the Layers panel, turn on Gallery > Earthquakes and Gallery > Volcanoes.
Fly around the world and zoom in until you see the earthquake and volcano placemarks. Using these as a proxy for tectonic activity, which of the statements below best describes your observations?
|
|
|
| 3b. Check and double-click placemark Problem 3b to fly to the Canadian Shield near Hudson Bay. Here, metamorphic foliations have differentially eroded to show two distinct foliation trends of different ages (one truncating the other). What evidence do you see in the foliations to suggest that these rocks were once deeply buried and experienced tectonic deformation?
|
|
|