課件礦床學(xué)相關(guān)scott3canadian prec cugb0909ce

Examples

of

VMS

Deposits

(4)Note

significance

of

arcs/backarcsCanadian

Precambrian

(Bimodal-Mafic:

>50%

mafic,

>3%

felsic

(>50%mafic,

>3%

felsic)Zn-Cu-Ag-Au

sulfides

immediately

hosted

by

felsic

volcanics

but

mafic

orultramafic

volcanics

predominate

regionally.

Probable

“arc”

setting.VMS礦床實(shí)例 注意島弧/弧后重要性加拿大前寒武礦床(雙峰式-鐵鎂質(zhì):>50%鐵鎂質(zhì),>3%長(zhǎng)英質(zhì))Zn-Cu-Ag-Au

硫化物礦床，直接賦存于長(zhǎng)英質(zhì)火山巖為主而不是鐵鎂質(zhì)或超基性火山巖為主的區(qū)域。很可能得島弧環(huán)境.Canadian

Precambrian

Bimodal-Mafic

Massive

Sulfides加拿大前寒武紀(jì)雙峰式-鐵鎂質(zhì)塊狀硫化物SturgeonLake加拿大地盾綠巖帶KiddCreekRuttanArchean

(~2730

Ma)

Noranda-Bousquet

mining

district,

Quebec,Canada

(Economic

Geology

cover,

v.

102,

2007)加拿大魁北克的太古宙（2730Ma）Noranda-Bousquet采礦區(qū)Vertical

section,

Noranda,

Canada.

Ores

occur

atseveral

stratigraphic

levels.加拿大Noranda地區(qū)垂向剖面，礦呈多層水平產(chǎn)出4

kmH.

GibsonTypical

NorandaDeposit典型的Noranda礦床圖例塊狀礦物閃長(zhǎng)巖Amulet安山巖Waite

流紋巖/角礫巖Waite安山巖綠泥石化/黑云母化英尺米Gibson

andWatkins,1990LineamentsRhyolite

Breccias流紋巖角礫巖H.

GibsonCompare

Kuroko與黑礦比較最接近點(diǎn)末端玻質(zhì)碎屑巖Type

B

(distal)Noranda,Canada(Archean)Type

A(proximal)KiddCreek,

Canada(Archean)Tuffaceous

“Exhalite”凝灰質(zhì)噴氣巖Noranda,

Canada

(Archean)0305mEu

Anomalies

in

Metalliferous

Sediments含金屬沉積中的Eu異常Ruttan,

~1900

Ma(Gale

2003)Noranda,

~2700Ma(Kalogeropoulos

and

Scott,

1989)Vertical

section

through

a

vmsdeposit

showing

“zone

refining”

inwhich

elements

are

redistributedby

dissolution

and

reprecipitationin

circulating

hot

hydrothermalfluid.VMS

礦床縱剖面，具有分帶特征，其中元素在循環(huán)熱液作用下通過溶蝕和再沉淀而重新分配。Massive

sulfideStockworkMillenbach

mine,

Noranda,

Canada(

Knuckey

et

al.1982)StructuralControl

of

theSturgeon

LakeArchean

VMS,Canada(grabens

andintersectingfaults)加拿大太古宙SturgeonLake

VMS型礦床中構(gòu)造控制作用（地塹及交叉斷裂）Mumin,

Scottetal.

(2007)Typical

Hydrothermal

Alteration

of

Rocks

Hosting

VMS

Ores.

Example

fromNoranda,

Canada

(Archean

~2730

Ma;

Gibson

1990)VMS型礦床圍巖中典型的熱液蝕變，加拿大Noranda地區(qū)實(shí)例（太古宙~2730

Ma)Alteration

Type

蝕變類型Mineralogy

礦物Diagenetic成巖階段的Palagonite

Zeolites

ClaysOxides

玄武質(zhì)玻璃沸石粘土氧化物Temperature

200

-250oCSpilitic細(xì)碧巖化Chlorite

Sericite Epidote

Albite綠泥石絹云母綠簾石鈉長(zhǎng)石Temperature

300

-350oCEpidote-Quartz

(“Epidozite”)綠簾石-石英Epidote

Quartz綠簾石石英Temperature

????Silicification硅化Quartz

Albite石英鈉長(zhǎng)石Distal

fromoreAdjacent

tooreIncreasing

distanceFootwall

Alteration

Controlled

by

Permeability受透水性控制的下盤蝕變Mumin

&

Scott

(unpublished)Summary

ofmineralogicalchangesapproaching

ore,South

Bay

mine,Canada

(Archean)Increase

in

Mg加拿大SouthBay礦床礦體周圍礦物變化特征小結(jié)（太古宙）Urabe

and

Scott

(1983)CoreMatrixChlorite

composition,

Ti

mineralogy

and

δO18

in

footwallandesite

breccia

at

Noranda,

Canada

(Archean)下盤安山質(zhì)礫巖中的綠泥石成分，Ti礦物和δO18金紅石榍石δ18O

=Oxygen

Isotope

Haloes

at

Noranda內(nèi)華達(dá)氧同位素異常暈侵入體VMS礦床VMS礦體露頭478

analyses

from

371sites371個(gè)地點(diǎn)的478個(gè)分析數(shù)據(jù)Metamorphic

equivalents

of

rock

types

associated

with

VMSdeposits

(Sangster

&

Scott,

1976,

after

Hutchinson,1970).

與VMS礦床有關(guān)的相關(guān)變質(zhì)巖石類型Primary

or

low

grademetamorphic

rock未變或者低級(jí)變質(zhì)巖Medium

grademetamorphism中級(jí)變質(zhì)巖High

grademetamorphism高級(jí)變質(zhì)巖Chert玉燧Siliceous

schist硅質(zhì)片巖Quartzite石英巖Rhyolite

and

rhyolite

tuff流紋巖及流紋巖類Quartz-feldspar

sericiteschist

or

gneiss石英-長(zhǎng)石絹云片巖或片麻巖Quartz-feldspar

gneiss石英-長(zhǎng)石片麻巖Andesitictuff

(chloriteschist)安山巖類（綠泥片巖）Biotite-chlorite-quartzschist

黑云母-綠泥石-石英片巖Biotite-quartz

gneiss黑云母-石英片麻巖Andesite

(chlorite

schist)安山巖（綠泥石片巖）Epidote-plagioclaseamphibolite綠簾石-斜長(zhǎng)角閃巖Hornblende-plagioclase-amphibolite

gneiss角閃石-斜長(zhǎng)角閃片麻巖Basalt玄武巖Epidote

amphibolite綠簾石角閃巖Amphibolite

gneiss角閃片麻巖Metamorphism

of

a

footwall

chlorite

alteration

zone下盤綠泥石化帶的變質(zhì)作用scaleChlorite

+

QuartzCordierite

+Anthophyllite

+Hornblende

+Biotite±

(garnet,tremolite-actinolite,Ca-pyroxene)“Dalmatianite”Chloritized

rhyolite

stockwork綠泥石化流紋巖網(wǎng)脈2

cm“Dalmatianite”

underground“Dalmatianite”

on

surfaceDeformation

and