G148

Objectives Week 8

 

1)  Understand the basic structure, the history and current activity of the Cascade volcanic range.

 

2)  What is the primary rock/material that makes up the John Day area and why is this area so important?

 

3)  What is meant by a stratified volcanic chamber and explain the two possible scenarios that create varying eruptions.

 

4)  How does a stratified volcanic chamber relate to Newberry volcano?

 

5)  What is meant by a bimodal volcano and be able to name at least one NW volcano that is bimodal.

 

6)  Understand what a collapsed caldera is and be able to name two in Oregon.

 

7)  Be able to explain the hazards associated with silicic volcanism and which one is the biggest concern in the NW

 

BASALT:

 

1)  Why are there so many different types of basalt.  Be able to discuss the different processes that creates different types of magma

 

2)  What is the basic structure of a shield volcano?

            Central caldera                                      Magma chamber

            Rift systems                             Fumeroles

           

3)  What causes rifts to form and what types of eruptions often occur along them? 

 

4)  What is the basic eruptive characteristics of basalt volcanism and (for the most part) how do they rate on the explosivity scale?

 

5)  Understand how the following features form and what the basic characteristics are for each

            Cinder cones                                        Fire fountains

            Basaltic lava flows (general)                Pele’s hair and tears

            Lava lakes                                          

 

6)  How do lava rivers (channelized flows) develop and what other types of features can they turn into

 

7)  How do lava tubes develop and how can they be recognized after the volcano stops erupting?

 

8)  Know the difference between pahoehoe and 'a'a lava and understand how each develops

 

9)  Why do lava flows inflate and what are tumuli?

 

10)  Understand what the following features are and how they are formed

          tree casts and molds                               columnular jointing

          kipukas                                                  biscuit jointing

          benches                                                 entabularture jointing

          bombs                                                    intercanyon flows

 

11)  What type of geologic settings is basaltic volcanism found in?