EXAM #2 answers

EXAM #2 answers - NAME _Mr Answer_ STUDENT # _ Geology 3950...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
NAME ___ Mr Answer _________ STUDENT # _________________________ Geology 3950 – Natural Catastrophes; Spring 2008 -- Hour exam #2 (90 points) I. (4 points) What is the age of the Earth? 4.6 b.y How long ago did the Moon form? 4.6 b.y. How old are the oldest rocks of the continental crust? 4 b.y __ How old are the oldest rocks of the oceanic crust? _ 200 m.y. II. ( 4 points ) What is the source of heat energy inside the Earth that drives plate tectonics? _________ radioactivity ___________________________________ Has this energy source increased or decreased during Earth history? decreased ____ How does most of this energy get released from the earth? __ heat flow from all over the Earth’s surface _______________ What is the source of energy that drives atmospheric circulation, weather and climate? _____ the sun/sollar radiation/hydrogen fusion in the sun III. (4 points) What chemical types of magmas are erupted at mid-oceanic spreading ridges? _____ basalts ________ How are these magmas generated in this tectonic environment? __ by decompression melting of the upwelling mantle __________ ____________________________________________________________________ Are these eruptions generally passive or explosive? ____ passively _______ Why? _______ because these basalts have low water content and low viscosity ___________ IV. (4 points) What chemical type of magmas are erupted in convergent plate boundary volcanic arcs above subduction zones? _____ andesites/rhyolites ___________ How are these magmas generated in this tectonic environment? ____________________ ____ by melting of the mantle above a subduction zone fluxed by subducted water Are these eruptions generally passive or explosive? ___ explosive _________ Why? ____ because of their high water content and low viscosity ______________________
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
NAME ________________________________________ V. (5 points) What chemical type of magmas are erupted above hot-spots in oceanic regions like Hawaii? ___ basalt ____ What chemical type of magmas are erupted above hot-spots in continental regions such as Yellowstone Park?___ basalts and rhyolites _____ What type of volcanoes or volcanic landforms form the Hawaiian islands? _ shield volcanoes What type of volcanoes or volcanic landforms occur in Yellowstone park? _ calderas
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

EXAM #2 answers - NAME _Mr Answer_ STUDENT # _ Geology 3950...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online