Igneous refinement of quartz raw materialsRune B. LarsenFrancois JacamonBjorn Eske SorensenNorwegian University of Science and Technology

Peter M. IhlenAxel MüllerGeological Survey of Norway

GSA, Salt Lake City, 2005

• High purity quartz• High end products • Silica glasses• Optical lenses, light bulbs• Fibres, insulators

• Polycrystalline silica• Solar grade silica (?)

Trace elements in qz, which, where and why ?

Typical abundance in igneous quartz

Analytical approach

Melt composition, igneous evolution qz-comp.

Subsolidus modification

LA-ICP-MS is the preferred analytical method

Al: <10 – 1000

Ti: <1 – 200

Li: <1 – 30

P: <1 – 30

K: <5 – 20(?)

Fe: <1 – 20

B: <1 – 10(?)

I-type Metaluminous Granites and GP’s

Charnockitic pyroxene-granite

Hornblende granite

Pyroxene-hornblende granite

Hornblende-biotite granite

Biotite granite

High T

Low T

A-TYPE GRANITIC ROCKS - CHARNOCKITES

Pedersen, 1988

Quartz TE abundance

(Ge/Ti) rock evolution

0.01

conc

entra

tion

( m

ol/m

ol S

iO2)

0.1

1

10

100

1000

0.05

Ti

Li

P

Ge

Be

Al

Pyr- Bi-graniteHbl-

Pyr-granite

Hbl-Bi granite 1

Hbl-granite1

Bi-granite 1

Pyr-Hbl granite

Hbl-granite 2

Hbl-Bi granite 2

Bi-granite 2

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0.000 0.020 0.040 0.060 0.080 0.100

Ge/Ti

Li (p

pm)

Lithium

0.00

50.00

100.00

150.00

200.00

250.00

300.00

0.000 0.020 0.040 0.060 0.080 0.100

Ge/Ti

Al (

ppm

)

Aluminium

Aluminium and lithium behaviour

PHOSPHORUS

Pyr-granite

Hbl-Bi granite 1

Hbl-granite1

Bi-granite 1

Pyr-Hbl granite

Hbl-granite 2

Hbl-Bi granite 2

Bi-granite 2

0.00

5.00

10.00

15.00

20.00

25.00

0.000 0.020 0.040 0.060 0.080 0.100

Ge/Ti

Apatite out?

S-TYPE PERALUMINOUS GRANITES

Müller et al., 2002Podlesi, Czech Republi

Müller et al., 2002

Primary Qz

Early Secondary Qz

Late Secondary Qz

Igneous differentiation form quartz with low Ti, Fe, K and B contents. Ge and Li is increasing. P and Al may also increase

Peraluminous granites, form qz with high Al contents. Evolved metaluminous granitic qz is low in this element

Largely, the quartz composition is buffered by the melt composition

Li, B, Al and Fe is lowered during hydrothermal recrystallization

K is not seriously influenced. The Na concentration may increase markedly

Ti, Ge and P are normally immobile during recrystallization

Qz is quite robust during subsolidus weathering and may largely preserve igneous fingerprint

Accordingly, qz partially preserve the igneous history and distinguish magmatic events in igneous complex terrains

Granitic pegmatite, particularly metaluminous and hydrothermally infiltrated GP’s are promising targets for HPQ prospecting

GSA, Salt Lake City, 2005, Rune B. larsen