Nature of Ore-Bearing Fluids

Question 1

Ore-bearing fluids

Answer 1

Magma/Magmatic Fluids

Hydrothermal Fluids

Question 2

is a high temperature rock melt of liquid and crystals

Answer 2

Magma

Question 3

oxide or sulfide dominated magma that solidify directly as ore

Answer 3

Ore magma

Question 4

a process where a partly crystallized magma is subjected to stress, the fluid fraction is squeezed off from the residual crystalline mush

Answer 4

Filter pressing

Question 5

coexistence between two liquids and their separation from each other

Answer 5

liquid immiscibility

Question 6

high temperature

Answer 6

100C - 800C

Question 7

Hydrothermal Flow Mechanisms

Answer 7

Fluids released due to magma cooling

Density differences induced by intrusion

compaction of sediments

osmotic pumping

salinity differences

hydraulic pressure difference

metamorphic recrystallization of hydrous phases

Question 8

fractionated fluids and volatiles that travel upward from the magma

Answer 8

magmatic/juvenile waters

Question 9

Chalcophile elements

Answer 9

Cu, Pb, Zn, Ag, Au, As, S

Question 10

Large Ion Lithophile

Answer 10

Li, be, B, Rb, Cs

Question 11

Alkalies, AEE, Volatiles

Answer 11

Na, K, Cl, Ca, CO2, H2O

Question 12

Deacrase viscosity of magmas, lower freezing points of minerals, make possible devolpment of minerals/complexes that would not form in a dry melt

Answer 12

Fluxes

Question 13

Elements that do not fit in feldspars and mafic silicate

Answer 13

LILEs

Question 14

any water that passed through and equilibrated with the atmosphere

Answer 14

Meteoric Water

Question 15

a medium of dispersion of dissolved ions, molecules, and suspended particles

Answer 15

Seawater

Question 16

Effects of Hydrothermal Fluid Density

Answer 16

Solubility of volatiles and non-volatiles solutes in supercritical water varies inversely with density

chloride complexes dissociate as hydrothermal fluid density decrease

Question 17

water trapped in sediments at the time they were deposited

rich in Na and Cl

Answer 17

Connate Water

Question 18

connate and meteoric water subjected to heat and pressure from magmatic intrusion

Answer 18

Metamorphic Waters

Question 19

can be derived from the breakdown of hydrous minerals

Answer 19

Metamorphic Waters

Question 20

products of hydrothermal fluid flow

Answer 20

Veins

Breccia

Hydrothermal Alteration

Question 21

tabular veins of minerals that precipitated from hydrothermal fluids

Answer 21

veins

Question 22

mineral growth in fluid-filled space

Answer 22

Distant Veins

Question 23

planar body of hydrothermally altered rock adjacent to a fracture or a channelway

Answer 23

Replacement Veins

Question 24

fluid is flowing through a rock

Answer 24

Open System

Question 25

result of rock fragmentation in a pressure gradient

Answer 25

Brecciation

Question 26

Causes of Fragmentation

Answer 26

Tectonic Gravity collapse in open of fluid-filled space explosive release of pressurized fluid

Question 27

veins form due to local redistribution of fluids and solutes in a rock

Answer 27

Closed System

Question 28

a chemical replacement of minerals where a fluid delivers the chemical reactants and removes the aqueous reaction products

Answer 28

hydrothermal Alteration

Question 29

Commong Alteration Rxn | 8

Answer 29

``` Hydrolysis Hydration Alkali or Alkali-Earth Metasomatism Decarbonation Silication Silicification Redox Sulfidation ```

Question 30

Alteration Type qtz, ms, tpz with common accessories of tur, fl, rt, cst, wolframite

Answer 30

Greisen

Question 31

Alteration Type bt, kfelds plus one ore more of the ff: ser, chl, qtz

Answer 31

Potassic

Question 32

Alteration Type ab, chl, ep, zeo, sme at low temp

Answer 32

Propylitic

Question 33

Alteration Type qtz, ser, py, chl

Answer 33

Sericitic

Question 34

Alteration Type qtz plus one or more of the ff; kln, dck, prl commonly ser, py, alu, tur, zunyite, tpz, dsp

Answer 34

Advanced Argilic

Question 35

Alteration Type sme, kln, crs

Answer 35

Argilic

Question 36

Alteration Type qtz, crs, trd, rt or ant

Answer 36

Silicic & Residual Silica

Question 37

Alteration Type cal, dol, ank, sd

Answer 37

Carbonate

Question 38

Alteration Type Ca and Mg silicates

Answer 38

Skarn