Geochemistry Part 2

Question 1

Usually measured in percentage, and are commonly above 1% of the chemical composition of the material

Answer 1

Major Element

- by changing the major element, you are essentially changing the materila itself.

Question 2

Elements that occur in such small comcentrations that they do not chnage the essence of what a material is. Usually below 0.1%

Answer 2

Trace elements

- it tells you what happens in the process and history of the rock.

Question 3

In between of major and trcae elements, mostly accessory minerals. Ithas concentration between 1% and 0.1 percent

Answer 3

Minor elements

Question 4

Oins that do not fit into the structure of the rock-forming minerals or minerals precipitating in the magma at the time when ions are present and therefore accumulate in the residual magma. Mostly concentrated in the melt

Answer 4

Incompatible elements

Question 5

Iosn easily accomodate in the minerla structure, mostly concentrated in the solid.

Answer 5

Compatible elements

Question 6

2 sub groups of incompatible elements

Answer 6

High Field Strength elements (HFS)

Large Ion lithophile elements (LIL)

Question 7

17 chemical elements inperiodic table, specifically the 15 lanthanide plus scandium and ytrium.

Answer 7

Rare Earth Elements (REE)
-they are in fact not that rare and are relatively abundant in the earth’s crust, what is unsual is to find them in quantities significant enough to support economic mineral development.

Question 8

Magma derived from the mantle with forsterite no. 88 to 92, magnesium no. Of 65 and above and low Cr number

Answer 8

Primitive magma

Question 9

The first magma derived from primitive magma. Can be classified as parental magma

Answer 9

Primary magma

Question 10

Not necessarily primitive nor primary but where other magmas derived

Answer 10

Parental magma

Question 11

Petrogenetic indicators: highly compatible elemets, its high concentratins indicate a mantle source, limited fraction, or crystal accumulation

Answer 11

(Ni, Co, Cr)
Ni and Co - concentrated inolivine
Cr - spinel and cpx

Question 12

Petrogenetic indicators: very incompatible elements that do not substitute into major silicate phases, high concentration imply an enriched source or extrusive liquid evolution

Answer 12

Zr and Hf

Question 13

Petrogenetic indicators: HFS elements that partition into Ti-rich phases. Typically low concentrations in subduction-related melts

Answer 13

Nb and Ta

Question 14

Petrogenetic indicators:Seredophiles mostly used to study melting and crystallization in maric-ultramafic systems.

Answer 14

Seredophiles: Ru, Rh, Pd, Re, Os, Ir

Question 15

Petrogenetic indicators: concentrates in pyroxenes and may be used as an indicatr of pyroxene fractionation

Answer 15

Sc

Question 16

Petrogenetic indicators: substitute for Ca in plagioclase and to a lesser extent, K for K-felds.

Answer 16

Sr

Question 17

Petrogenetic indicators: myriad uses in modelling source characteristics and liquid evelution.

Answer 17

REE

Question 18

Petrogenetic indicators:commonly incompatible. Strongly partitioned into garnet and amphibole.

Answer 18

Y

Question 19

Non destructive analytical technique used to determine the elemental composition of materials.

Answer 19

XRF - X-ray flouresence

Question 20

Uses of XRF

Answer 20

Petrology
Soil survey
Mining
Cement
Metallurgy 
Envi Studies
Petroleum

Question 21

Primary, non destructive tool for identifying and quantifying the mineralogy of crystalline compounds in rocks, soils, abd particulates.

Answer 21

XRD (X-ray Diffraction)

Question 22

Spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the stable state.

Answer 22

Atomic Absorption Spectroscopy (AAS)

- it can determine over 70 elements in solition or solid sample

Question 23

An analytical technique accompanied by counting the number of ions at a certain mass of the element. It only analyzes liquid samples.

Answer 23

Inductvely Coupled Plasma Mass Soectrometry (ICP-MS)

Question 24

The time taken for the radioactivity of a specified isotope to fall to half its original value

Answer 24

Half life