ORE DEP (FELSIC PHANEROCRYSTALLINE)

Question 1

Deposits related to Felsic Phanerocrystalline Rocks

Answer 1

1) Pegmatitic
2) Granitic Tin
3) Granitic U
4) IOCG (Iron Oxide, Copper-Gold)

Question 2

Generally dike like or lensoid which formed late in the crystallization associated with plutonic or Hypabyssal Rocks where volatiles cannot readily escape but in the deep seated high pressure environment

Answer 2

Pegmatites

Question 3

Mineralogically simple, unzoned, formed when the more mobile qtzfldsphtc constituents of a rock are concentrated in dilation openings during met differenntiation and does not have economic value

Answer 3

Metamorphic Pegmatites

Question 4

Products of Plutonic activity (Precambrian - Present )

Answer 4

Igneous Pegmatites

Question 5

Type of pegmaites that is Uranium bearing but are not economical

Answer 5

Syenite Pegmatites

Question 6

The only pergmatites associated with economic deposits

Answer 6

Granitic Pegmatites

Question 7

a.k.a Unzoned Pegmatites

Answer 7

Homogenous Pegmatites

Question 8

Zoned Pegmatites which are results of one period of crystallization after injection of water rich siliceous late stage melt

Answer 8

Heterogenous pegmatites

Question 9

4 zones of heterogenous Pegmatite

Answer 9

1) Border Zone - outermost and have the Same mineralogy as wall zone but finer grained
2) Wall Zone - Plag, Perthite, Qtz and Muscovite subordinate tourmaline, apatite, Berly and garnet
3) Intermediate Zone - Up to 11 subzones can be present
4) Core Zone - Solid Mass of Barren Milky qtz w/ feldspars or qtz w/ large crystals of tourmaline or spodumene

Question 10

IN what type of Granites is Uranium most abundant?

Answer 10

I-type granite, Alkali-rich Granites, S-type, pegmatites and related veins

Question 11

Enrichment of U increases in

Answer 11

Silicecous Fractionated Late Melt

Question 12

Morphology of Uranium

Answer 12

Disseminated and less veinlets

Question 13

Main Ore

Answer 13

Uraninite

Question 14

Other U-bearing Mienrals

Answer 14

traces in
Allanite
Titanite
Zircon
Monazite
Uranothorianite (U Th)(SiO4)2
Coffinite and
Brannerite

Question 15

80% of the World’s Present Tin production came from this type which is a specialized, advanced differentiates of crustally derived granitoid melts due to partial melting of continental crust or sed rocks in orogenic belt

Answer 15

Tin Granites

Question 16

Mainly the host granite which is cahracteriszed by two mica (Musco and Biot) more felsic that I-type, non porphyritic, shows internal variation, commlyn foliatied and assoc. w/ Met rocks and Orogenic Belt

Answer 16

S-Type Granite (Mas continental in origin)

Question 17

Age of Granitic Tin

Answer 17

Phanerozoic

Question 18

Example of Granitic Tin

Answer 18

Blue Tier, Tasmania

Question 19

Deposits which are most productive Sn Deposts which are closely spaced nearly vertical greisen veinlets that extend to considerable deph

Answer 19

Floor

Question 20

Highly altered granitic rock or pegmatite and is formed by self generating alteration of granite

Answer 20

Greisen

Question 21

What type of skarn is Greisen?

Answer 21

Endoscarn

Question 22

Deposits that are defined primarily by their elevated magnetite and/or hematite contents, constitute a broad, ill-defined clan related to a variety of tectono-magmatic settings.

Answer 22

Iron Oxide Copper Gold

Question 23

Characteristic of IOCGs

Answer 23

1) No clear spatial associations w/ igneous intrusons but has a borad space-time assoc w/ Batholitic Granitoids and alkali Metasomatism
2) Has greater Fe oxides w/ Fe or Ti than most igneous rocks and bulk crust
3) Abundant Magnetite and Specularite (Crystalline Hematite)
4) Hydrothermal Ore style w/ strong structural controls

Question 24

Example of IOCG

Answer 24

Olympic Dam, Australia