Chap 7/8: Phase Diagrams

5.0(2)
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/24

flashcard set

Earn XP

Description and Tags

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

25 Terms

1
New cards
rock-forming minerals
mineral group composed of the most common minerals found in earth
2
New cards
major element
chemical elements that occur in large amounts
3
New cards
minor elements
elements with abundances btwn 1.0 and 0.1 percent
4
New cards
trace elements
elements that occur in smaller amounts
5
New cards
triangular diagram
a diagram that allows for graphic representation of mineral chemistry in terms of three end member groups
6
New cards
Al2SiO5 polymorphs and their conditions
* Kyanite, lower temperature and high pressure
* sillimanite, high temperature
* andalusite, low to mid temperature and low pressure
7
New cards
polymorph definition
a group of minerals that have the same chemical composition but different structure
8
New cards
two uses of the phase diagram
* predict which phase we will find
* use the phases to understand the temperature and pressure history
9
New cards
tectosilicates
SiO2 polymorphs, feldspars, sodalite
10
New cards
chain silicates (inosilicates)
tetrahedral chains

* single - pyroxenes
* double - amphiboles
11
New cards
sheet silicates (phyllo)
infinitely extending tetrahedral sheets

* talc, micas, chlorite,
12
New cards
nesosilicates
corner oxygens link to other cation polyhedra instead of link with other silica tetrahedra

* (SiO4)4+, andalusite polymorphs
13
New cards
sorosilicates
double tetrahedral units

* epidote
14
New cards
cyclosilicates
ring structures

* beryl, tourmaline, and cordierite
15
New cards
invariant point
can only exist at one temperature and pressure
16
New cards
univariant line
one variable can change but all others would be fixed
17
New cards
divariant field
both temperature and pressure can be varied independently without changing the number of phases
18
New cards
liquidus meaning
Temperature at which a mixture of minerals is completely liquid
19
New cards
solidus
Temperature below which a mixture of materials is completely solid
20
New cards
tie line
line in phase diagram joining coexisting minerals
21
New cards
fractional crystallization
a realistic crystallization, doesnt matter where the starting composition is as it will always end up at the same place
22
New cards
solid solution
homogenous mixture of two different kinds of atoms in solid state and have a single crystal structure
23
New cards
miscibility gap
a region in a phase diagram where the mixture exists as two or more phases, forms exsolution lamella upon cooling
24
New cards
zoning
composition changes from the inside out
25
New cards
eutectic
minimum-melting composition of 2 or more components, each of which melts and freeze congruently forming a mixture of the component crystals during crystallization