What does the Bowen's reaction series represent? - ANSWERSBowen determined that specific minerals
form at specific temperatures as a magma cools. At the higher temperatures associated with mafic and
intermediate magmas, the general progression can be separated into two branches.
How do porphyritic-textured igneous rocks form? - ANSWERSPorphyritic rocks are formed when a
column of rising magma is cooled in two stages. In the first stage, the magma is cooled slowly deep in
the crust, creating the large crystal grains, with a diameter of 2mm or more.
Which lines get closer together as they approach the poles? Lines of latitude of lines of longitude (circle
one)? - ANSWERSLatitude and longitude comprises a grid system of lines encircling the globe and is used
to determine the locations of points on the earth. Lines of latitude, also called parallels, run east - west.
Latitude lines always run parallel to each other, and hence, they are always an equal distance apart.
What could explain the asymmetry of magnetic stripes on the ocean floor? - ANSWERSThe magnetic
stripes represent fluctuating polarity changes of the Earth's magnetic field preserved in the basaltic
ocean crust. The reversals have been dated using K-Ar dating producing a paleomagnetic time scale
What is the difference between fracture and cleavage for a mineral? How can you distinguish between
them when looking at a sample? - ANSWERSFracture is the characteristic way a mineral breaks. The
difference between cleavage and fracture is that cleavage is the break of a crystal face where a new
crystal face is formed where the mineral broke, whereas fracture is the "chipping" of a mineral.
What does mafic mean? What are two mafic minerals? - ANSWERSMafic is an adjective describing a
silicate mineral or igneous rock that is rich in magnesium and iron, and is thus a portmanteau of
magnesium and ferric. Most mafic minerals are dark in color, and common rock-forming mafic minerals
include olivine, pyroxene, amphibole, and biotite.
What does felsic mean? What are two felsic minerals? - ANSWERSIn geology, felsic refers to igneous
rocks that are relatively rich in elements that form feldspar and quartz. ... Felsic refers to silicate
minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen,
aluminium, sodium, and potassium.
How does lava viscosity affect the slope of a volcano? - ANSWERSthe more viscous the magmas a
volcano erupts, the steeper the volcano. Thus, shield volcanoes like we have in Hawai'i have gentle