With a Geological Twist

Lava Tubes

Lava tubes form when channels of moving lava cool at the surface of the channel enough to develop a crust. They are usually developed during basaltic eruptions. The crust acts as an insulating layer, keeping the moving lava beneath the crust fluid. The viscosity of the melt beneath the crust remains low and the tube acts as a conduit. Many lava fields gain their large aerial extent because lava tube carried the molten material to distant reaches of the field. Lava tubes also play a factor in distributing the heat carried to the surface by volcanic products.

Arrested stages in the development of lava tubes are well displayed at Diamond Craters in Oregon. Lava tubes played an important part in the development of the Craters of the Moon lava field.
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Volcanic Petrology
Theory and Analysis
    Characterization of Volcanic Rocks
    Mass Balance Constraints
    Thermodaynamic Modeling
     Current SelectionClassification of Volcanic Rocks
    Statistical Tests of Mass Balance Constraints
    Optical Mineralogy
Magmatic Histories
Computer Programs
Studies of Rock Suites
Maps of Volcanoes
Web ExerciseClick on the button to start a Web Display that helps explain classifications of volcanic rocks. To return to this page, close the window that opens.
Lava Tube

 Classification of Volcanic Rocks

Each of the subsections under theory and analysis gives you access to three electronic documents. These documents are Portable Document Format (*.pdf) files. The documents can be read on the screen or printed. To read and print the documents, your computer will have to have Adobe's Acrobat Reader. Adobe Acrobat Reader is furnished free of charge and you can obtain it by clicking on the following button:

Adobe Reader

NewThe electronic documents can be downloaded to your computer by clicking the right mouse button when the cursor is over the underlined text fragments in the immediately following:
Text file describing methods for classifying and identifying volcanic rocks:
Part4.pdf
Figures that accompany the text on classification and identification of volcanic rocks:
Figures4.pdf
Tables that accompany the text on classification and identification of volcanic rocks:
Tables4.pdf