Rocks

Question 1

Igneous rocks

Answer 1

Molten rock that solidifies either beneath surface or following eruption at the surface.

Question 2

Weathering

Answer 2

Physical breakdown and chemical alteration of rocks at earths surface.

Question 3

Lithification

Answer 3

The process that turns loose sediment into a sedimentary rock

Question 4

Sedimentary rock

Answer 4

Sediment lot higher when compacted by overlying materials or when cemented as percolating groundwater fills the pores with mineral matter

Question 5

Metamorphic rock

Answer 5

Initial rock and subject to heat and temperature so minerals rearrange into new more chemically stable structures

Question 6

Rocks

Answer 6

Aggregates of grains of one or more minerals

Question 7

Magma

Answer 7

Molten rock generated by partial melting of rocks in earths mantle and in the lower crust in smaller amounts

Question 8

Extrusive/volcanic

Answer 8

Igneous rocks that form when molten rock solo firs at the surface

Question 9

Intrusive/plutonic

Answer 9

Igneous rocks that form at depth

Question 10

Texture

Answer 10

Overall appear have of an igneous rock, based on size and arrangement of its interlocking crystals

Question 11

Fine grained texture

Answer 11

Igneous rocks that form rapidly at surface or as small masses within the upper crust have fine-grained texture, with the individual crystals too small to be seen with the unaided eye

Question 12

Vesicular texture

Answer 12

Vesicles left by gas bubbles that formed as the lava solidified

Question 13

Coarse-grained texture

Answer 13

When large masses of nagana solidify far below the surface they form igneous rocks that exhibit coarse grained structure. Appearance of a mass intergrown crystals , roughly equal in size and large enough that individual minerals can be identified with the unaided eye.
Eh. Granite

Question 14

Porphyritic texture

Answer 14

Large crystals embedded in matrix of smaller crystals. Produced by slow then rapid cooking

Question 15

Glassy texture

Answer 15

Produced by very rapid cooling eh. Pumice or obsidian

Question 16

Dark silicates

Answer 16

Rich in iron and or magnesium and relatively low in silica. Eh. Olivine, pyroxene, amphibole, biotite mica

Question 17

Light silicates

Answer 17

Greater amounts of potassium sodium and calcium and are richer in silica. Eg. Quartz, muscovite mica, feldspars

Question 18

Granitic (Felsic) rocks

Answer 18

Rocks composed almost entirely of light colored silicates (quartz potassium feldspar)

Question 19

Basaltic (mafic) rocks

Answer 19

Rocks that contain substantial dark silicate minerals and calcium-rich plagioclase feldspar (but not Quartz) have basaltic composition. Contain high percentage of dark silicate minerals. Typically darker and denser than granitic rocks

Question 20

Andesitic (intermediate) rocks

Answer 20

Composition b/w granitic and basaltic rocks. Contain mixture of both light and dark colored minerals mainly amphibole and plagioclase feldspar

Question 21

Ultramafic rocks

Answer 21

Composed of almost entirely dark silicate minerals. Peridotite mostly olivine and pyroxene. Very rare at earths surface

Question 22

Bowen’s reaction series

Answer 22

Describes order of crystallization as magma cools
From top to bottom:
-decreasing temp
-dark to light color
-decreasing density
-increasing viscosity
-Ca, Mg, Fe --> Si, Na, K

Question 23

Magmatic differentiation

Answer 23

The formation of one or more secondary magma a from a single parent magma

Question 24

Mechanical (physical) weathering

Answer 24

Physical forces that break apart a rock

• frost wedging
• thermal expansion
• unloading
• biological activity

Question 25

Chemical weathering

Answer 25

Alteration of minerals by removing or adding elements

Question 26

Detrital sedimentary rocks

Answer 26

Rocks formed by sediments that originate as solid particles from weathered rocks (detritus)

Question 27

Chemical sedimentary rocks

Answer 27

Rocks made of soluble material produced by chemical weathering. Dissolved substances precipitate back as solids called chemical sediment.

Question 28

Compaction

Answer 28

As sediments accumulate through time, the weight of overlying material compresses the deeper sediments

Question 29

Cementation

Answer 29

Cementing materials carried in solution by water percolating through the pore spaces between particles. Over time, the cement precipitates into the sediment grains, fills the open spaces, and joins the particles.

Question 30

Metamorphism

Answer 30

Process that leads to changes in mineralogy, texture and sometimes the chemical composition of rocks.

Question 31

Contact/thermal metamorphism

Answer 31

Rock intruded by magma. Change is caused by rise in temperature within host rock surrounding mass of molten material.

Question 32

Regional metamorphism

Answer 32

During mountain building, great quantities of rock are subjected to directed pressures and high temperatures associated with large-scale deformation.

Question 33

Foliation

Answer 33

Any planar (nearly flat) arrangement of mineral grains or structural features within a rock. Eg. Slate, schists, gneiss Non foliated: marble, quartzite

Question 34

Crystallization/solidification

Answer 34

Process by which Molten rock cools and solidifies