Natural Processes Of Geomaterials

Question 1

Bowen’s reaction series describes

Answer 1

The susceptibility of common rock-forming minerals is to chemical weathering

Question 2

In the bowen’s series, the higher a minerals melting point . . .

Answer 2

The higher it’s susceptibility to chemical weathering

Question 3

Minerals in the bowen’s series have melting points ranging from

Answer 3

1200-700°C

Question 4

The most to the least reactive of the bowen’s series is

Answer 4

Olivine
Ca-plagioclase
Pyroxene
Hornblende - yo wtf
Biotite - BOY YOU TIGHT
Na-plagioclase
Orthoclase feldspar
Muscovite
Quartz

Question 5

Sedimentary rocks can be divided into two principal groups

Answer 5

Clastic (exogenic)
Non-clastic (endogenic)

Question 6

What is meant by clastic/exogenic rock?

Answer 6

Exo- originate externally to the earth’s surface

Question 7

What is mean by a non-clastic/ endogenic rock?

Answer 7

Endo- originates from within the earth- volcanoes etc.

Question 8

What are the six deposition’s environments from top to bottom

Answer 8

River bed
Lake
Beach
Tidal flats
Shallow Marine
Deep marine

Question 9

In engineering terms what is a well graded, poor sorted aggregate mix?

Answer 9

Many sizes of grains, a good mix for engineering applications

Question 10

In engineering terms what is a well sorted, poorly graded aggregate mix?

Answer 10

An aggregate mix of similar size grains

Question 11

Which kind of rock has a <0.004mm grain size?

Answer 11

Clay

Question 12

Which kind of rock has a <0.004-0.06mm grain size?

Answer 12

Silt

Question 13

Which kind of rock has a 0.06 - 0.25mm grain size

Answer 13

Fine sand

Question 14

Which kind of rock has a 0.25-0.5mm grain size?

Answer 14

Medium sand

Question 15

Which kind of rock has a 0.5-2mm grain size?

Answer 15

Coarse sand

Question 16

Which kind of rock has a 2-4mm grain size?

Answer 16

Granules

Question 17

Which kind of rock has a 4-64mm grain size?

Answer 17

Pebbles

Question 18

Planes of weakness in sedimentary rocks correspond to

Answer 18

Direction of mineral deposit

Question 19

What is meant by a rock sample that exhibits anisotropic behaviour?

Answer 19

Does not behave the same in every direction

Question 20

What are three clastic sedimentary rocks?

Answer 20

Conglomerate (with gravels)

Sandstone

Shale (mudstone)

Question 21

What are three non-clastic sedimentary rocks?

Answer 21

Carbonate rocks (limestone)

Evaporites (salt rocks)

Carbonaceous (peat,lignite,coal)

Question 22

What does metamorphism mean?

Answer 22

Solid-state transformation of pre-existing rock into texturally or mineralogically distinct new rock.

Accomplished through high temperature, high pressure or both

Question 23

What are the technical names for the three types of metamorphosed rocks?

Answer 23

Thermal/contact metamorphism (temperature)

Dynamic/dislocation metamorphism (stress)

Regional (temp + stress)

Question 24

In the recrystallisation of metamorphic rocks, what happens to voids?

Answer 24

They are filled by intergrown crystals

Question 25

What are folliations?

Answer 25

Layers in rock formation induced by directional pressure

Question 26

From low grade to high grade, what are three foliated rocks?

Answer 26

slate, schist, gneiss Slate is late, gneiss is nicely at the top

Question 27

Metamorphic rocks are not defined by their appearance or rock content but rather by their grade of metamorphism. What does this grading involve?

Answer 27

Crystal size, coarseness of foliation, band size The bigger the better

Question 28

How are non foliated metamorphic rocks formed?

Answer 28

Metamorphosed through temperature alone (thermal/contact)

Question 29

What is the name of minerals formed through metamorphism?

Answer 29

Garnite

Question 30

What are the rock strength tests?

Answer 30

Brazilian tensile test Point load test Unconfined compression test

Question 31

Why does the Brazilian tensile test involve?

Answer 31

Cut a puck of the rock sample Place the puck between two presses Apply pressure on both sides Break the rock

Question 32

What the does the point load test involve? (Is 50)

Answer 32

Cut out a cylinder of rock Place between two conical points Apply pressure through the points Measure resistance Rock breaks

Question 33

What does the unconfined compression test involve?

Answer 33

Cylinder of rock is cut out Placed between two presses Pressure applied until rock breaks (Essentially Brazilian tensile test with a cut cylinder as used in the point load test)

Question 34

The direct shear of rocks in done using what apparatus ?

Answer 34

Triaxial cell

Question 35

How is the Is50 point load strength index calculated?

Answer 35

IS50=P/De^2 P is failure load De is the equivalent core diameter

Question 36

What is the most common way to describe the strength of a material?

Answer 36

List it’s UCS

Question 37

What features are important when classifying sandstone specimen?

Answer 37

Dott's classification chart. The main clast constituent matrix percentage Grain shape

Question 38

Olivine and pyroxene are the first to be removed by weather from an igneous rock sample, why? (exclude Bowen's reaction series as an explanation)

Answer 38

They are the simplest silicate based minerals form weak connections between minerals, thus easy to break first to come out of solution from magma pool