Shunso IsHIHARA*
Transcript of Shunso IsHIHARA*
報 文
553.43(71)
S⑫鵬㊧ C畳皇e識置ce畳 《】幽認暫麗C重e暫量S重葦CS ⑰宜重畳亘e 互餓重暫聡S量ve ROC盈【S ⑭ぜ
曲㊤聡e翻e恥e騰P⑰聯恥y暫yC⑪欝e姻》e脚s置重s,B。《】・,c鋤我幽
By
Shunso IsHIHARA*
Abstract
The results ofpreliminary chemical and optic翫1study ofthe intrusive rocks ofthe Beth.
1ehemporphyrycopperdeposits,B.C。,Canadaarereportedandarecomparedwithsimilarintru.
sive rocks ofthe United States。The intrusive rocks related in time and space to the porphyry
copper mineralization in North America seem to have a wide range ofcomposition,but belong
to caユc-a工kaユic rock series with two exceptions of sub-aユkalic rock series.Of these rocks,the
Bethlehem intrusives are characterized by the leastpotassic and most c呂1cic nature。Thepropy.
1itic alteration at Bethlehem can be regarded as the Iowest grade alteration in the general sen“e,
but the potassium-poor nature ofthe host intrusive rocks,besides P-T conditions,seems to be
an important factor fbr the absence ofpotassic silicate assemblages in the alteration zone,
亘期重蜜odl量黒ct置⑰醜
The Bethlehem-coPPer deposits,10cated.in Highland Valley in the southem interior of British
Columbia,Canad.a(Figure1),are generally understood as porphyry coPPer-type ore deposits。They
are composed of fbur known ore bodies of Huestis,Jersey,East Jersey and Iona,and relatively new
Valley Copper.HIRATA(1965)pointed out many similarities ofintrusive rocks,structural fもatures,and
modes of occurrence of sulfide distribution between the Bethlehem copper deposits and.the so-called
porphyry copper deposits in the United States and South America.
The Bethlehem copper deposits are situated.at the center of the Guichon batholith,which as a
whole intrudes volcanic rocks of the Upper Triassic Kamic stage and is unconfbrmably overlain by
Middle and upPerJur&ssicmarinesedimentaryrocks(cARR,1966).The:K-Ar mineral age is200±5
m.y.(WH皿EandCARTER,1968)。AtBethlehemtheGuichonb翫tholithis divided into two m司’or units
ofolder quartz diorite andyounger quartz diorite(RIRATA,1965).The fbrmer is the main phase ofthe
Guichon batholith.The latter consists of stock-1ike fbrm of the Bethlehem quartz diorite(Figure2),
dike-fbrming dacite porphyry and crowded porphyry,and intrusive breccia.
CARR(1966)statedthat1)theyoungerquartz diorite contact,2)porphyryintrusionandaccompany-
ing brecciation,and3)faults,are important factors to locate both mineralization and alteration.
The mineralization is a combination of sul飼e vein,.stock-work,and dissemination.Chalcopyrite,
bomite,molybdenite,and specu1乱rite are the major opaque mineralsンbut pyrite is rather rare。
Chloritization,epidotization and argillization are distict.Sericite is also present.:Little tourm&1ine occurs
in the matrix ofbreccia pipe ore bodies(EIRATA,1965)。
During a short visit to the Bethlehem mine in1968,the writer collected a small amount ofhand
specimens.Four selected specimens were analyzed and a fもw other specimens microscopically examined.
* Mineral Deposlts Department
1一(535)
1
!
鋭 (0 ◎ 鋤
、!亀、
顕鼠
♪亀
地質調査所月報
助3θ・
1\
(第22巻 第10号)
W120。
⑪
\
\も」f \鰻
\
画 鴨
隅⑭ 幽㌔ ⑮ 舳
驚
蝿
㊥
砂㎏
暗’
臥
鶏
馬
ノ
憩 ⑧
\\▽へ
¥Q一
、Q lΦ ’
’
J
lo1、
1,
/
、N6巳
\
い6G
灘灘
韓溝
蝕 ∫η去アα51ソθ
尺oc船
O
噛
mts2QG
(q〉¥黛
\Q一 ¥づ ¥一
も
’、
¥Q
¥べ
¥P
¥つ
¥
\\ やo
\も
\\
\\
\
灘圏亀 ¥ 曳 軸 、
蹴留竃 v
.談鑛♪ U. S. A・
N52。
ハ伽γ 9θ0/09/o mαρ
Fig.1 Location of the Bethlehem coPPer deposits in the Canadian Cordillera.
The fbllowing description is based on this preliminary examination。
A臨魏y麗dt s艶ec量蹴磯s
Chemical analyses of the fbur specimens are listed in Table L The samples were collected in the
Jersey pit,where even rocks with丘esh outlook were altered to various degrees.The analyzed specimen
2一(536)
Intrusive Rocks ofthe Bethlehem Porphyry Copper Deposits(S.IsHIHARA)
20005 θ000ε
x X × × × ×
x )く × × 〉ぐ × ×
X X
×X ×
X ×
× x
× x〃α6誠3 xx × × × × × x ×
4,欝贈 ×
0 2000
X X × X × X x
も & 球
Fig.2
× ×
も×ミ.諺 び
x
x
X
×
×
×
×
14000κ
、臨 ロ 嵐 X
も 饗 麟 、灘一x
簸 聾 1× 懸 き
講嚢 灘纒鞍プと9…〃
鍼 鞭 纂
罵噸 蓼 碧× ま 慧、圃βr畑Pどρθαηゴβ7θ・・どα 謂θ耐/即脚,
醗囎βθオ顧θ麗轍z伽漉θ ρα7ぬ5卯Z撒
回鋤・脇αオz∂∠。rlオθ
Location of the£our orebodies distributed around the margin of the Bethlehem quartz diorite.
No.10f the Guichon batholith is a hollocrystalline medium-grained rock with the IC number
(CHAYEs,1956)of83.The grain size seems to be muchβner than that of common granitic rocks
exposed in the core of the circum Paciβc belt.The Japanese examples of the granitic rocks show the
IC number around40(lsHIHARA,1971).The major constituents are,in order of abundance,plagio-
clase,ma且c minerals,quartz,and potassium fddspars.Potassium fddspars occur in small amount but
are distinct in hand specimens because of the slightly reddish brown color.The color is darker than
thatofordinaryquartzdioriticr・cks.
Microscopic observation indicates t五at plagioclase 翫nd mafic minerals are mostly euhedral.
The interstices are filled with mainly anhedral quartz。Normative plagioclase composition as the whole
is about An40(Table1)。The plagioclase is rarely zoned,and always contains specks of alteration
minerals such as sericite,actinolite,albite,and clay minerals。The secondary albite occurs also in the
interstices of plagioclase。There are no fyesh mafic minerals in the analyzed specimen。The observed
minerals are actinolite,chloriteラand epidote。The outline of the pseudomorph indicates biotite and
hornblende to be the original minerals.
The analyzed specimen No。20f the Bethlehem quartz diorite is very similar to the specimen
No.1,but it is slightly価er(IC number of114),Iighter-colored,and prophyritic due to aggregates of
amphiboles.Under the microscope the alter乱tion is weaker than that ofNo,L Plagioclase is more com-
monly zoned.Normative plagioclase is calculated as An35.Potassium色ldspars批re subhedral and show
microperthitic structures with irregular fbrm of albite lamellae.Amphiboles have been con』vertcd to
chlorite,opaque minerals and carbonates,but a part of biotite is retained in the chloritization.The
biotite has Y≒Z ofpale brown,which is o£ten described in hydrothermally altered zones ofsome ore
3一(537)
隣
Table1
地質調査所月報(第22巻第10号)
Ghemical analyses of the intrusive rocks費om theJersey pit,Bethlehem coPPer
deposits.
Sample No.
S.G.Bulk
Powder
Sio2
Tio2
A1203
Fe203
FcO
MnOMgOCaONa20K20P205
CuFe
S
SO3
H20(+)
H20(一)
Total
il
ap
mgpyor
ab
an
cWOen角
qz
Total
Femic total
or十ab十qz
DI an!an十ab x100
Analyst;K.OHTA.
1
2.67
2.82
60.71
0.6816,9壬
2.39
2.66
0.09
2.69
5。55
4.31
1.04
0.24
<0.01
2.16
0.32
99.78
1.29
0.52
3.46
tr
6.15
36.47
23.79
0.97
6.70
1。96
15.99
97.30
14.90
58.61
60.2
39.5
2
2.74
2.7些
66.19
0.29
17.42
1.19
1.54
0。03
1.25
4.23
4.41
1.31
0.13
0.04
0.04
1.46
0.16
99.69
0.55
0.28
1.73
0.08
7.74
37.32
20.24
1.33
3.11
1.36
24.31
98.05
7.11
69.37
7σ.8
35.2
3
2.70
2.75
64.89
0.38
17.35
1.20
2.28
’ 0.04
1.51
4.43
3.77
0.52
0.15
tr
O.25
0.29
<0.01
2.62
0.06
99.74
0.72
0.33
1.74
0.54
3.07
31.90
21。08
2,86
3.76
2.64
28.41
97.05
9.73
63.38
65.2
39。8
4
2.62
2.74
67.60
0。39
16.79
0.10
1.47
0.03
1.40
2.32
4.32
0.78
0.14
0.33
0.63
0.72
<0.01
2.40
0.28
99.70
0.74
0.31
0.14
1.35
4.61
36.56
10.67
4.93
3.49
2.04
31.85
96.69
8.07
73.02
75.5
22。6
No.1:Guichon quartz diorite,Jersey pit4,900ft benchl2:Bethlehem quartz diorite,4,900ft benchl3:
Altered Bethlehem旦uartz diorite(chilled phase),4,700ft bench34:Altered and mineralized Bethlehem quartz
diorite,4,700ft bench。
Fe=equivalent to each sulfur content in the£orm ofFさS2subtracted£rom Fe203.
deposits occurring in granitic rocks。
The specimen No.3is a porphyritic rock with aphanitic m翫trix.Ma且c minerals are the most
distinctive phenocrysts.Under the microscope,the rock shows a porphyritic texture with phenocrysts
of plagioclase and mafic miner&ls in the cryptocrystalline groundmass(Figure3)。This is a ch皿ed
phase ofthe Bethlehem quartz diorite having slightly more‘‘basic,,composition than the proper phase
4一(538)
Intrusive:Rocks ofthe:Bethlehem Porphyry Copper Deposits(S。IsHIHARA)
Fig.3 Photomicrograph of the analyzed specimen No。3。
難Fig.4 PhotomicrQgraph of the analyzcd specimen No.4。
5一(539)
地質調査所月報(第22巻第10号)
ofthe Bethlehem quartz diorite(Table1).The rock is also altered moderately in the same mamer as
the specimens No.1and No。2.Presence of epidote-group minerals,mainly of clinozoisite,is quite
prominent in replacing the original maGc minerals.Specks of sericite in plagioclase are much clearer
than that of the specimen No.L Normative pyrite is about O。5%。The copper content is not more
than O,05%。
The analyzed specimen of No.4is乱n altered&nd slightly mineralized rock of the Bethlehem
quartz diorite.This rock consists of phenocrystic plagioclase and groundmass of sugar-like aggregates
ofquartz,plagioclase(albite),and mafic minerals(Figure4)。This groundmass may have been fbrmed
through recrystallization process by hydrothermal altcration.The survived plagioclase has been partly
sericitized and argillized,as shown by specks of sericite and day minerals.:Larger crystals of Haky
sericite&re seen in the limited parts of the groundmass.Some sericite Hakes constitute a part of
chloritized biotite。This sericite must have been conve践ed f士om biotite。The orig圭nal m面c minerals in
general have been completely altered.to chlorite and epidote。Disseminated copper su1Hdes in most
cases occur associated with these ma且c alter乱tion products.The assemblage of the altered minerals
indicates thatthespecimenbelongstopropyriticalteration ofCreasey(1966).More advancedalteration
of sericite-quartz assemblage is observed in the restricted parts around molybdenite and/or coPPer
sul且des-bearing quartz veins or fヒactures at Bethlehem.
Resu亙ts踵d恥terpre重at量磯
Z砂%吻8706ん5: The analyzed,Bethlehem qu&rtz diorite is relatively f士esh,while the Guichon quartz
dioriteisslightlyaltered as described intheprcvioussection.Eowever,t虹esespecimensm段ybeconsidered
丘esh rocks among those fをom porphyry copper deposits.The two guartz diorites show the fddspar ratio
between quartz diorite and granodiorite(Figure5).The characteristic is the higher contents of quartz
andplagioclase.Atypicalevolution trend Ofa calc-alkalicrockseries on this diagram should be fyom the
plagioclase comer to the quartz.orthoclase side.1ine。Most ofthe United States examples fbllow roughly
this trend except fbr those f士om the Bingham and Robinson.The Bethlehem intrusive rocks are more
O z
十 βeぎ力乙eカθ侃
巴 γθ71〃9オoπ
口 〃e w OO7月θ〃α
△ 8ノρ9カα侃
△ 尺0かノ〃50η
㊦σωかθ~尺αy ・B βα9げα4
0CD Oα5オεθ Oo〃正θ
●SM 5απ ’》α〃αθ乙
x」r
oW 犀α77θπ
oM 〃oγθπCl
o 3αノ7オα 尺ノ‘α
4 0SM {+} oCD
(亀/+ ・諾w
2十 十 〇
、/B謹M・。謬。急。
O ム ム
品 全
▲△ ▲ ム ▲ ▲ ▲
\.\
P‘・ 0γ
Fig.5 Normativefeldsparsandquartzoftheintrusiverocks£romtheselectedNorth American porphyry copper deposits.
6一(540)
Intrusive Rocks of the Bethlehem Porphyry(】opper Deposits(S.IsHIHARA)
Table2 Additional chemical analyses of the intrusive rocks丘om,the
Highland Valley area,collected by T.Tatsumi in1970。
Sio2
Tio2
Al203
Fe203
FeO
MnOMgOCaONa20K20P205
CO2・ S
H20(+〉
H20(一)
Total
沼自㊤⇒
窃自
oOo〉
’二
ご
自さ乞
il
ap
mgor
ab
an
cWσ
en角
qz
Tota1
1401
67.17
0.27
17.10
1.16
1.26
0,06
1.07
3.98
4.15
1.77
0.14
0.03
0。02
1.10
0.28
99.56
0.51
0.31
1.68
10.46
35.12
18.90
1.手2
2.66
1.03
26.04
98.13
1411
63.27
0.36
16.77
1.16
1.26
0.06
1,12
4.76
3.46
2.62
0.15
2.06
0.Ol
2.60
0。22
99.88
0.68
0.33
1.68
15。48
29.28
22.48
0.10
2.79
0.88
21.28
94.98
1501
71.68
0.18
15.66
0.68
0.68
0.04
0.47
2.46
4.53
2.03
0.08
1.15
0.20
99.84
0.34
0.17
0.99
12.00
38.33
11.76
1.70
1.17
0.46
31.57
98.49
Femic total 6.46 3.13 6。19
qz十ab十〇r 66.04 81.90 71.62
DI 69.5 83.2 73.O
an/an十ab×100 43.を 23.5 35.O
Analyst:K.OHTA1401;Betblehem quartz diorlte at Lornex.This specimen is actually coarse-grained actino
lite-biotite granodiorite,and some p1批g三〇clase has been strongly sericitized&nd argillized.
141L‘‘Porphyrite,,at Jersey pit,Bethlehem,This specimen can be called altered dacite
porphyry.Sericitization and carbonatization are distinct;while epidotization and chloriti-
zation are moder銭te.1501 Bethsaide granodiorite at southwest of the Valley Copperorebody(ca.2,000ノ).This is coarse-grained homblende(?)一biotite granodiorite.Epidoti.
zation is rather obvious.
calcic and silicic th翫n those of the United States。In addition to the Bethlehem quartz diorite,there
are many porphyries of dacitic composition related to coPPer mineralization in time and space at
Bethlehem.These porphyries must be more potassic than the:Bethlehem quartz diorite(e.g.1411,Table
2).However,it seems to be true that the Bethlehem copper mineralization is related to more calcic
intrusive rocks than those of the United St&tes.
The alkali-lime index by Peacock(1931)also indicates c既lcic character of the intrusive rocks at
Bethlehem・Although the number of the analyses is limited,the fbllowing Ggures can be given fbr the
rocks fヒom the North American porphyry copper deposits.
7一(541)
地質調査所月報(第22巻第10号)Fθ203+1『θ0
!一\ メ // \
//
/㊦ 1一一 ろ オ ノ オ /△塗▲ノ/
//雛醐・
/ シ の の
鬼+//
縄/。M
ハ1α20+
κ20 MgO
Fig。6 M-F-A diagram of the intrusive rocks from the selected NQrth American
porphyrycoPPerdeposits.
About61:Bethlehem,Globe-R.ay area(Castle Dome),Santa Rita.
59:New Comelia
58: Yerington
56:Bingham,Robinson。
According to this index,these rocksね11into therangeofcalc-alkalic suite.The Bethlehemis inthemost
calcic side,while the R.obinson and Bingham in the most alkalic side.In the M-F-A diagram,most of
the rocks are plotted in the zone ofcalc.alk翫1ic series rock.Those ofthe:Last Chance and Bingham stocks
occupy a distinctively di任erent field and show a dif驚rent trend.(Figure6).The term calc-alkalic is des-
ignated in many ways(KuNoラ1969),so that it is needed to examine other characters after having more
chemical data。In the Harker’s diagram(Figure7)乱distinctive dif断ence between intrusive rocks of
the Bethlehem and,United States porphyry copper deposits is seen in:K20whose content is low at Beth-
1ehem.
Table3 Chemical exchange between the unaltered and altered Bethle一
hem quartz diorite(mg/cc),
Sio2
Tio2
Al203
Fe203
FeO
MgOCaONa20
K20Cu
FeS2
H20(十)
No.2
1813.6
8.0
壬77.3
32.6
42。2
34.3
115.9
120.8
32.1
2.2
4:0.0
No.4
1771.1
10.2
439.9
2.6
38.5
36.7
60。8
113.2
20.4
8.7
35.4
62.9
Losses&gains
一 42.5
十
十
十
2.2
37.4
30.0
3.7
2.4
55.1
7.6
11.7
8.7
十 33.2
十22.9
8一(5を2)
Intmsive Rocks ofthe Bethlehem Porph》αy(】opper Deposits(S.IsHIHARA)
55 60 65 70 乃
18
ノθ
ノ4
4
2
4
2
6
4
2
6
4
6
4
2
θ
4
2
血
血
《
《
《
△ △
△ 朗△ B㊥。++・M訟圏△\・㌔謎Lよ尋。
島 口oかず騒@ 議 《 ♂ 塩 ㊥SM 圏
魅
ム
釜査幽 O SM
・グ計一、瀞巽L_.
十 ②SM+ +
團△全
△△亀 ム ム
企
\鬼 卜 △合十 〇 口 △
㊥SM
&
《 《
\\SM血
十
o
㊥
㊥
河1203
㊤
、、隻+ \ \㊥CD⑧CD \ \
w O
⑱CD
囲
\ ㊥⑬
oM
㊨CD 而203
》ト\ 恩 \
・曾財>・遡誤斐~肥 M。⑬曾 ⑪+ w。
勉塩\農㊨SM血△△△ △ \、きoも
△+毯s謡極圏。團曾_、CD ”90 M⑲留、⑧㊥£D←~~恩
会ム會△《 ⑲。ム^㌧ +△
^口\\之 ㊥
\O 十 十 ㊥SM血B@・晶’ロ>
0α0 εo.論CD執
CD \\9
O
B ⑧ 十
祭企畑ノ.一△~ト8鮮 △
古ooSM
oM 囲
十 團㊥
⑱
㊥
⑲
十
_1
〃α20 ./
/ W O
wO
Wo
WO
WO
Wo
血
o
o
㊥ ⑲CD㊥CD
メ⑤CD ,⑯ノ圃 圃㊥㊨ $ ⑱
OM
κ20
,凶一馳繭国圖一Wo
w♀
w6
愈於△%企△《 塩 ム ム
!一一一’ー
ム / 圏 働 OoSM十
口
十
O 口O
ヘハSMoQ 口 OB㊥⑳
十
十十
17
15
13
!1
!
3
ノ
5
3
!
5
3
1
5
3
5
3
1
.55 θ0 65
3102 %
70 乃
Fig.7 The Harker diagram of the intrusive rocks from the selected North American porphyry copper deposits、
Booken line=general trend of the Sie皿a Neveda Batholith(BATEMAN et aL,1963)
9一(543)
地質調査所月報(第22巻第10号)
Ch6痂6α16hαng6躍瞬鴛8α166剛ぎoπ:Each component ofthe specimens No.2and No.4was calculated in
mi11igram per cub三c centimeter and compared to each other in ord、er to know the losses and gains
during the propyritic alter乱tion(Table3).This comparison is debatable because the original composi-
t量on of the specimen No。4must be different fヒom that of the specimen No.20wing to heterogeneity
ofthe Bethlchem quartz d.iorite.Neverthelless,there are coincident losses and gains to the mineralogical
changes observed under the microscope.The loss in C批0,Na20,and K20agress to d.ecomposition of
fbldspars。No considerable changes are seen on m葡c elements as the whole.SiO2and A1203decrease
slightly.
CO躯C且US量ve Rema置鼠S
1) The intrusive rocks at Betlllehem belong to a calc-alkalic suitc.They&re乱n example of the
commonestintrusive rocks in British Columbia ofsaturated series ofBRowN(1969,p.34).Intrusive rocks
ofdiorite-monzonite-syenite series reported by BR.owN(1969)are not observed among the area of the
porphyry copper deposits examined in this papeL Some intrusive rocks in the Robinson are抗are
normatively undersaturated ones,but they seem to become saturated rocks continuously du血g the
丘actionalcrystallization.
2) The most related,rocks to porphyry copper mineralization are classifie{1as granodiorite to
quartz monzonite in North America(TITLEY and HIGKs edit.,19661RIDGE edit。,19681WILsoN,19631
GILLERMAN,19641BRowN,1969).The Bethlehem examples批re quartz diorite to granodiorite.This
means that the intms呈ve rocks are characterized by low content ofK20,as compared wi重h those ofthe
United States.The reason is perhaps because the Bethlehem copper deposits are located close to the
core of the CordiIlera Orogeny。
3) The mineral assemblage of the altered intrusive rocks at Bethlehem can be regarded as that
ofthe fyinge altαation zones ofthe United States examplesラwhich have no commercial copper contents。
:Low content ofpotassic silicates at Bethlehem,however,could be consistent with the Iess potassic nature
of the host intrusive rocks.
4) The miner乱l assemblage may also be related to the low content of the total sulfides,which
could have been an important catalyzer fbr some minera1.pars d.u血g the silicate reaction.
5) The low content ofthe total sulfides seems to be the prime agent fbr l乱ck ofchalcocite blanket
at Bethlehem,as pointed out also by HIRATA(1965),among various causes such翫s glacial truncation,
climate condition,rather abundant carbonates,and others.But the content was enough to fbrm
secondary oxide ores with no enrichment(e。g。Iona orebody).
∠46んηoω」64g躍6η♂:The writer is ind.ebted.to the staf琵of the Bcthlehem Copper Corpor乱tion,Ltd。,£or
their guide to theJersey pit,and Mr.Y.HIRATAofthe sumitomo Met&1Mining co.ofcanada,Ltd.,
fbrhis adv三ce on Canadian geology and reading the original manuscript。The manuscript was also kindly
reviewed by Dr.H.OTsu of the Sumiko Consultants Co。,:Ltd.The writer is most gratefhl fbr
Professor T.TATsuMI of the University of Tokyo fbr providing samples fbr the analyses。
(The original manscript completed inJanuary1970)
10一(544)
Intrusive Rocks ofthe Bethlehem Porphyry Copper Depos圭ts(S.IsHIHARA)
Ci琶;ed匿 Re£elre鵡ces
ANDERsoN,c.A.,scHoLz,E.A.,and sTRoBELL,Jr。J、D.(1955):Geology翫nd ore deposits ofthe Bagdad
area,Yavapai County,Arizona。U。S.0601。8徽7。P7g五Pψ67278シ103p。
BATEMAN,P.C.ラCLARK,1。.D。,HuBER,N.K,MooRE,」.G。,and RINEHART,C。D。(1963):The Sierra
Nevad.a batholith=A synthesis of recent work&cross the central part.U,S。0601。S㍑7∂.P7φ.
P砂67414-D,46p.
BAuER,,∫r.H.1・.,BREITRlcK,R.A.,cooPER,J.J.ブand.ANDERsoN,」。A。(1966):Porphyry coPPer
deposits三n the:Robinson mining districtシNevada。乞nσ60Jo劃げ渉h召Poψ妙ぴ(7ψゆ67Dψo読5-
3傭hω6s渉徽No7渉h!歪規6γ加。Univ。Ariz.Press,Tucson,p,232-244。
BRowN,A.S.(1969):Mineralization in British Columbia and the copper and molybdenum deposits.
σ1ノレずB%IJ.,vo1.62,P.26-40。
BuTLER,B,S.,:LouGHLIN,G.F.,HEIKEsラV.C。,and Others(1920):The ore deposits of Utah.α乱
Gl601.3躍∂。P7qゾPαψ67111,672p.
CARRン」,M(1966)l Geology ofthe Bethlehem and Craigmont copper deposits.勉7協o航備吻姻
ノ匠2n67α11)4)05露59ブ渉ゐ6晩5陀7n(7074露187α.CIM Sp.vo1。8,P。321-328.
CHAYEs,F。(1956):P伽g吻h乞6窺04α1αn伽乞3John Wiley&Sons,Inc.,N.Y。,113p。
CREAsEY,S。C。(1965):Geology ofthe San Manuel area,Pinal County,Ariz。乙孔S。σ601,S%7∂.P7び.P吻7
471,64p.
CREAsEY,S.C.(1966):Hydrothermal alterationjnθ4010紗げ孟h6Poψ妙ワσ吻67」Dψ05づ孟5-So麗伽65’67η
瓦o禰∠膨7初。Univ.Ariz』Press,Tucsonラp.51-74.
GILLERMAN,E。(1964)=Mineral deposits ofwestem Grant CountyラNew Mexico.瓦M6κ.Bπ7.ハ4傭,
Bz61」。83,213p.
GILLuLY,」。(1946):The Ajo mining district,Ariz.U.S。θ601.翻7∂。.P7911Pψθ72091112p.
HIRATA,Y,(1965):Geology and mineral deposits of the Bethlehem properties,:B.C.,Canada。〃1診痂g
σ601.Toゆo,voL15,p.75-82,
IsHIHARAラS.(1971):M勾or molybdenum deposits and related granitic rocks inJapan。Rψ哲。θ601.S蹴
」αψ‘zη,no.239,178P.
JoNEsラW.R.,HERNoN,R.M,,and MooRE,S.L.(1967):General geology ofSanta Rit批quadrangle,
Gr乱nt County,New Mexico.U。&060」.伽∂.P噸Pψ67555,144p.
KNopF,A。(1918):Geology and ore deposits of the Yerington district,Nevada.U.S。0601.S撹7∂.P7嫉。
Pψ67114,68p.
:KuNo,H.(1965):Some problems on c乱lc-alkali rock series。Joμ7.」ζψ.イ435.〃冨n67..P6渉7。E60n.,vol。53,p.
131-142.
KuNo,H.(1969)=Andesite in time and space.伽P706θ6伽g3gμhθ∠η磁3露6(70ψ76n66.Intern.Upper
Mantle Prqj.,Sci』Rept。,16,p.13-20。
LINDGREN,WALDEMAR(1905):The copper deposits ofthe Cli位on.Morenci district,Ariz。U。8.θ601.
8躍∂.Pηプl Pψ6743,375p.
MooRE,W.」。,LANPHEREりM.A.,and oBRADovlcH,J。D。(1968)=chronology ofintrusion,volcanism,
and ore deposition at Bingham,Utah.E60η,0601。,voL63,p.612-62L
PEAcocK,M.A.(1931):Classi且cation ofigneous rock series。Joπ7.060」.,vo1.39,p。54-67。
PETERsoN,:N.P.(1962):Geology and ore deposits of the Globe-Miam玉d玉strict,Ariz.U.5しθ60ムSπ7∂.
P7げ二P卿7342,151P.
11一(545)
地質調査所月報(第22巻第10号)PETERsoN,N’.P.,GILBERT,C.M.,and QpIGK,G.:L.(1951):Geology and ore deposits of the Castle
Dome area,Gila CountyラAriz.U,3。0601.S%7∂.B麗ZJ.,971,134p.
RIDGE,J.D.edit.(1968):076勿05才差吻Jh60漉4s渉伽1933/1967・AIME,N・Y・,voL II,P・992-1880・
TITLEY,S,R.and H:lcKs,(】。L edit。(1966):(ヌ6010劃げJh6ρoψ妙び6吻674ψ05露5-So彫hω6吻7n.〈石07渉h
廊26z蜘.Univ.Ariz.Press,Tucson,287p.
WHITE,W.H.and CARTER,N。C。(1968):Theageofsomemineraldepositsin British Columbia(abs.)
σZM∠4nn.ハ466あ箆g.1p.and l fig。
wILsoN,J.R.(1963)l Geology ofthe Yerington mine,ハ伽惚σo珍9765s Jo蹴,voL49,P・30-34・
カナダ,ブリティシュコロンビア州,ベスレヘム斑岩銅鉱床に関係する
貫入岩の化学的性質
石原 舜三
要 旨
ベスレヘム鉱床の花闘岩質岩石が予察的に調べられた。この貫入岩はカルク・アルカリ岩系の石灰質な種類に属す
る。銅鉱化作用ともっとも密接な貫入岩の岩質は,ノルム鉱物で石英閃緑岩~花嵐閃緑岩であって,アメリカ合衆国
の同種鉱床の場合より斜長石に富む。
ベスレヘム鉱床でもっとも普遍的な変質作用はCREASEY(1966)の分類によるプロピライト化変質に属するもので
ある。これは合衆国ではもっとも低度の周縁変質相である。しかし,ベスレヘム鉱床のプロピライト化変質の原因
は,カリウムに乏しい原岩の性質および硫化物総量が少ないなどの,原岩と鉱液の化学的性質にも由来するものと思
われ,温度圧力条件によって一義的に規制されたものではないらしい。
12一(546)