Instructions for use

Title Ultra-basic Rocks and Associated Ore Deposits of Hokkaido, Japan

Author(s) Suzuki, Jun

Citation Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy, 8(2), 175-210

Issue Date 1952-03

Doc URL http://hdl.handle.net/2115/35855

Type bulletin (article)

File Information 8(2)_175-210.pdf

Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP

wLryRAptBAsxc RocKs AND AssocxA"ueEg) oRE

]i)asroSKrlerS OF ffOKKAXDC), YA.PAN

By

Yv,fi SUZVKX

(With 9 Tables and 1 Text-figux'e>

Contribution from the Geologieal and Mineralogieal Department,

Faeulty o£ Seienee, Hokkaido Univevsity, No. 447

coNTEN'xrs

l. GEOLOC;ICAL CONSIDERA[['ION i･-･････････L･･L････i････=････+･i････4i

II. ULrDRA-BASIC ROCKS AND ASSOCIATED DIKE ROCI<S ･･･III. CONTACTMETAMORPHICROCKSRELATEDTO TllE ULTRA-BASIC rNTRUSIVES ･･･-････=･･･-･･-･-･･-････････-･･･

IV. ORE I)EPOSITS ASSOCIATED WITH SERPENTINITES ･･････ A. Chroinite deposits ････-･･-･･･-`･･･--･E-s･･･E････････-･･･-･L･･･-･J･･･4J･-･･･

B. E'lacer ehvom'ite deposits ･-････+-･L･･L･-･････a}･-･････-････････-･･E･i-･･-

C. Placer iridosrnine and plaeer gold deposits ･･･r････L･･4･･････-･･

D. Chrysotile asbestos deposits -･･-･････････････i･J･･-･L････J･････J･･-･･･

E, Mex=euyy deposits ････--･bLib･ib････i･E････････t･･･････････････-･･.i.....-･

F. Niekel deposits ･"'･････"･･･i･･･4･-･･iJ･･････-･･-･･･････4･･･J･･-･･-･･･--･･-･

G. Copper deposits ･･--･-･･-･･-･･･i･･･････-･･･+･･E･････"･･･-+･････････.･･.,....

N. Tale. a:id other depogits i･･････････････+-･････････-･-････････=-J-････-･J

V. SUMMARY '''･'tb'-･''･''--J-'i-･-･-'-'･--"i･-･･'-･b-･･--････E･-a--s･･-･

L![I]ERATURES ....,..,..,,....,.....,.................,,............,.,.........

Page17i)

11SO

]87

]90

191.

193

'1 95

197

201

202

L)02

2{)3

2e4

206

l. GEOLOGICAL CONSIDEftArX'10N

Geologieally spea}<ing the central zozie of Hok}<aido is very eomplex

foyming a speeial geoteetonieal unit in J'apan, and it offers many funda-

mental pi obleins whieh are well worth stixdy from various standpoints.

The wyiter, while engaged in the study ef various metamorphie yoe}<s

and adjaeent ultra-basie roeks o£ ehis eentral zone in the past years,became also deeply interested in ore deposits contained ii} the ul'tra-

basieroeks, The subjeet matter of this papey is an outline of theresults of field and }aboratoyy lnvestigatioRs with special referenee to

the ultra-basie yoeks and assoeiated ore deposits in }E[ol<kaido. Befoz･e

proeeeding to the eonsideration of these subjeets, it is neeessary to

Journ. Fae. Sei., Hokkaido Univ,, Ser. IV, Vol. VIII, No, 2, 195`.',

176 [;. Suzuki

give some aeeo"nt of the fundamental geology of the eentiyal zone of

Rokl<aido where the ultra-basie reel<s aye pyedomiiiantly developed.

In eentral Hokkaido, two speeial eomplexes, ealled respeetively the

Hidaka"･') eomplex a-nd the Kamuikotan`･2) eomplex, are extensively clis-

tributeci in belts, rumaing roughiy para}lei to each other in a longi-

tudinal direetion. In varieties altd natuyes of the roeks the Hidaka,

eomplex aRd the Kamuikotan eomplex are qulte different and as afiarrow belt of the Cretaeeous systeirn is usually developed betweeR

them, direet relation oifi these eomplexes has not yet been ascertained

in the field. Aiong the eastern side o£ the ffldaka eomplex, an un-}movgTn Mesozoic fonnat･ion is widely distributed, oR the oehe)r hand,

the membeys of Cretaeeous and Tertiary systeins are developed on the

west of the Kamull<ot･an complex, in eonseeut･ive order from theeast, running in a sub-payallel diree'tion wit･h elose relation te the axial

range of the Kamuil<ot-a neomplex (Ji}{no, 1892; Svzvm, 1944), (Fig. i).

Topographieally, the Hidal<a and Kamuikotai} complexes wit･h their

assoeiated intrusive masses generally form t･he mountaineous regions,while younge.y strata cons'tit･ute compayatively low-lands, as these iateer

roe}<s resist more feebly 'the agents of denudation.

The Hidaka complex is eomposed of the nor}nal Hidaka group altd

thiek sehaistein fox'mation. The prominent members o£ the group, areblaek sla'te and fine sandstoike interbedded with thin layers of limestone,

sehalstein and reddish quartzite. In the eent-ral zone of the normal

Hidaka grottp, espeeially aloftg the back-bone ridge of t-he Hidal<a

mount･ain range, there develops a thielc format-ion o£ hornfels, biotitegneiss, spot･ted gneiss, amphibolite, phyllite, ete,, aceompanying with

granit･ie, gabbvoic and peridotitic int･rusives (Svzmgi, 1934a; 1934-d). The

most of the gneissose roeks in tJhe group. were formerly eoiisidered by

many observers to be intrusive and h"ection gneiss whieh hacl bee.nrendez･ed erystalline by the lit-par-}it injeet-ion due to gi'aniti'c intrusion,

but are vegarded by present･-day geologist･s as mostly, if iiot wholly,

migmatite whieh has orlginated as a result of granitization (Suzm{iand NE]fo'yo, 1935; H,NsHi>fo[vo, 1948a, 1949; HuNAuAsi, 1949; SAwA,1950 ; ffvNtuiAsi and IilAsHisfo[vo, 1951).

[l]he thiek sehaist･ein formation, whieh develops along the "Test･ern

margin of the normal ffidaka group, eonsists ehiefiy of diabasie tuff,

agglomeyate, lava, sheet and dike. Doleritie reeks with spilitie ikature

which beay albite and aegiyine-augite as aeeessory eonst･ituents are partly

(l) Ll iE,C･li, (:')) ",ililitS,r'Ei'it,

UItxti-basie Roeks nnd Assoeiated Q,ye Depot)its of Hokkaido, japan l77

-en- ps- pm"± ' Mzatu!Wthetwn

ei;'

w@

-x------

.･A- -un--t"

A ---

---S6}II=- 3

t---zz

tt-vy-

.-y

axny.x

4v

ti,,iilill

L-. '-=v-"" f -nv Drrm Tt-trr .

L T-

-vma '

't'rm-i

ti=-

.L.

s

6

'

t

{

iSl;

.7 7"

;l6

1- '' )-:- k .' -- il=' ' :tt 'x 'd"." tu s.+ - l--k--- mM- Linv' '-r-mt'Lu-

--,..:-i---- (i."-,-,,}l-..---.tl-m-T{l.lii-}ewSII6

ua t --rmTT/-vrtMm um -u --rm-H.,ursl-m le[li -T '

"murmu-- e

HC-."

"a

.Xx

M

o so

'

t- t

lji OX-,

le6 KM

t

# Eiilii::i nMmm tr;{:i--ti-･,E-,k m m wax..$x.:

Kamuikotan 1-liaaka Cretaceous, '1'ertiary i)iluvium, Sevpentinite, Granite, complex eon].plex VnkT}own Alluviun) Peridotite Gabbve, MesQzoio Migmatite, ete. Fig. 1. Geolo.crieal sketeb map of E{okl<aido

Provinees: (1) Oshima, (2) Shlribeshi, (3) Ishikari, (4) Iburi, (5) Tesbio, (6) Kitaml, (7) H'idaka, (S) Tok'achi, (9) Kushiro, (IO) 'Nemuro. Rivers : (A) The 'Yeshio R,, (B) The Ishikari R,, (C) Ti}e Toi{aehi R., (D) The Uryu R,, (E> The Kamuikotan Valley.

exposed, aitd several instaces of pillow strueture have developed in .them (Suzvm, 1951). [I]he sehalstein formation is loeally psroupeCi to-

gether with the thiik Iayeys of yadiolarian chert aiid fossili'Eerous lime-

stone of the enizashi<i) series for whieh an early Jurassie age is mostprobal]}le (OfvArrsum;], 1.940 ; YA}m an(il Su(}iyA}i,N, 1941 ; }lv}{ttDA, 1949>,

Althollgh the roeks obtained from 'the. Hidaka eomplex show dis-

(I) )ig*il,

Ellllllllililil

,VoOq}k",anie

178 [Y. Suzukiti'nctive petrographie featiires common wi£h those from the so-cal3ed

Chiehibia`L') system <Permian-Carboni£erous) in Japan proper and othei'part･s, no erganie remains exeept the presenee of radiolayiaR easts in

some cherty yoeks and crinord stems in some limestones, have been

£oultd in them, whiie the stratigraphieal position and age of the eomplexare not yet elearly defined.

The zone o£ the I<amuikotan eomplex has been traeed for morethan 200 km, £rom Teshio(:') Provinee to Hidaka Provinee though someparts are eovered by young Tertiary and vo}eanie roeks. The mostexeellent oukLereps of the eomplex oeeur along t･he Kamuiko'tan Valley

of Ishikari(`' Provinee, from where the name o£ the eomplex was origi-nated. It is pyobable that the erysta}}ine sehlsts in the Suzuya mountain-

land hi South SaghailB represent, teetonieally and petrographiealiy

a part of the northern extension o£ the iarge zone of the Kamulkot･aikeoinpiex in Hold<aido (Svzui<i, 1934b).

The ehie£ petrologieal member of t･hG eomplex is blacl< silieeousschist and next eomes an abundanee of greensehlse. Small amountsof re(ldish quaytz･it･e, phyllite, n}ylonite, sehalstein and eyystaliine lime-

s'tone are int･ercaiated in the eomplex whieh is usua]ly aeeompani'edby ultra-basie roel<s oR a large scale. Of these erystalline sehists, the

siiieeous type ls assumed to be deyived from some siliceous or argillo-

silieeous sedimentaries and tFhe presenee of iresiduai grains of pyroxene

or unaitered bloel<s o£ diabasie roek in a member of the greensehistwould appear to indieatq that sueh roeks ori.o;inated in most ease fvom

sehalsteiix and diabasic roek. The original roeks have now been eon-verted int･o various greensehists such as diabase sehist, chlorite sehist,

albite epidete ehlorite schist, hornblende sehlst, etc. (Suzvi<i, 1932a;

2934b ; 1939e ; HvNtxi-iAsi, i951b),

The fundamental type roel< o£ the Kamuikotan eomplex are some-vLThat･ ,erystalline and sehistose in struet･ure, [I]he stril<e of their

sehistosity is usually parallel to t･he north-south h'end of the complex,

but in eer'tain loealities, it is nearly at a rig`ht angle to that trend

indicating that the roek layers show locally a clouble plunging antieliiie

or more eomplex strueture. For instanee, in the Kamliil<otan Valley,

t'he Ishikari River appears to fiow approxlmately along the sehistosity

of 'the roek erossing the general t+rend of the eomplex, In geneyai the

zone o£ the Kamuil<otan eomp!ex is bounded on both sides by uncon-formit･ies and yotmg fault･s whieh bz`ing the Cretaeeous or Tertiayy(?,> llSe6(), (g) 7<1.Eee..., (4> ill'fl":.

Ultra･-basie .Kocks and Associated etre Deposits of E[okkaido, japan 'i79

sedimentayies against the deformed crystalline sehists, though the natuL'e

of the boundary aloRg certain parts is obseure.

The Kamuikotan eomplex is, like t}ae Hidaka eomplex, provisional}ygrouped together vLri'th some layers which are eonsidered to be jurassie,

but as to the geological age of the whole Kamuikotan eomp}ex, nothiRg

eertain ean be said. From the geoiogieal and petrogyaphieal points of

view, it may reasonably be assumed that the Kamulkotalt comp}ex, sofar as the writer is aware, ean be readily correlated with the Furancisean

formation in Cali£omia, From late Mesozoie time eentral Kokkaido has been periodie?.llysubjeeted to earth-movemenCs produeing pressure from the east withaceompanying igneous aetivities. The effects are notieeable along thg

mount･ain range wheye the imbrieation o£ strata, great terrestyial dis-

plaeemene and de£ormation of roe!<s may be reeognized, As a yesult,it ls difieylt to estimate the thiel<ness of eaeh of the roek zones of

the Hidaka and Kamuikotan complexes on aceount of the overturningand repetition of their formation. The clearest examples of the orogenie

movement are to be found not only in the tyaets of the central zones

bue in ehe Palaeogene Ishikari coal fieid alono.' the westerlt margin of

the eentral Hokkaido zone. Reeumbent foids and overthrusts are often

seen thex'e (NA(;Ai¥o, etc,, 1933; NAGAwe, 1934), [i]he great erogeitie

movements in centra,i llokkaido aeeompaniect and £ollowed by meta-morphism, igneous activity and migmatisation, have been fully discussed

by M. }IuNixu.tsi and S. Hiystm{o[vo (195th) from the tectonic points of

view anct the whole activity is lumpect togethev as the "Hidaka orogeny"

by them. The ultra-basie roeks which will be ehiefiy eonsidered in the present

paper, have only a limited development, being restricted mainiy to the

teetonic lines in or along the metamorphic zones o£ the Kamuil<otaR

and Hidaka complexes, though the volume o£ the yoc}<s h} the latteris exeeedingly small and their petrologieal nature is usually different

eompayed with that o£ £he former. Large ultra-basic masses in theKamuikotan eomp}ex yuii appyoximately south-north in special sections

betvLTeen the Tesh!o-Kitami("' boundaries at the north £o Hidaka Provineeat the south. The outcrops of these ultra-basic roeks in the Kamuikotan

zone are bounded by eon£orted erystalline sehist of the Kamuikotaneoiinplex or by sedimentaries of Cretaeeous and Tertiary age though

loeally faults ean be reeognized along the boundarles between theo) y<ta.'es..-aiclil.

l8e ' J. Suzukiultra-basic roel<s aiid the others,

Some ultra-basic masses gave rise to eontaet metamorphie effeetswith the roel<s of the Kamuikotan eomplex and adjacent Cretaeeous

£ormation ; on the other hand ultra-basi.e yoel<s are enelosed as pebblesin the Neogene and Palaeogeiie Tertia･ry eonglomerate beds, ehe former

of whieh lie diyectly oii the ultra-basie masses. From these faets it

may probably be sa£ely assumed that t･he most of the iixtrusion ofehe large ukra-basic masses in the eentral Hokkaido zone beloi}gs toan eayly [I]ertiayy orogenie period (Mu.i{,t'rA, 1936 ; }IAnADA, 1939 ; Suzum,

X943b),

An outliRe of the ore deposits elesely yelated with the uitya-basie

reeks in the eentyal zolle of Hokkaido will be presented later in 'this papey, .

XK. VLrrRA"BASiC ROCKS AND ASSeCIATED DIKE ReCKS

As previously noted, the ultra-basie z'oel<s in Hokkaido usua}ly oecur

iR or a}ong ehe areas of the Kamuikotan eomplex in the form o£ com-paratively Iarge Ienses or be}ts extending fyom the ttorth to the south

in lineay direction along teetonie lines, but as small fragments, ultra-

basie roeks also oeeur in the metamoyphic zone of the Hidaka complex

(Suzvig 1939e; }{iuNAu.xsi, 1951a; }IluNAi-msi and fiAsmMervo, 1951).

ene o£ theix distineti`ve iffeatures is that the greatey portion o£ the ultra-

basie roeks ki yelation to 'the Kamuikotan complex is now representedby' serpentin{.te, but the ultra-basie yoel< of tke Hidaka eomplex is com-

payatively £resh anCl still shoviTs periCiot:/tic nature. Large serpentinitebodies in the Kamuikotan eomplex zone oecur in tlwee separate loca}lties,

viz,, the [!reshio-Kitami(i) iiRountain range, Uryu`2) mountain-laitd and

Yk'tbari-Yufutsu-Saru･(ti',distriet, in ovder fro].n the north to tlie south, The

most novtherly out･cyop is a youghly bek-formecl inass, covering aii area

of approximately 45 km, length by 7 l<m. maximum width, anct striking

about norCh and south. The outeyop ef the Uryut raeuntain-land, which

oeeuys some 40 km. to the south o£ the above, shows an irregular form,appvoximately 43 km, in leiigth aiid ie }<m. in width at the most southerly

part, rlsing with steep sides to a height of 7eO m, or more, above the

surroundhhg yotmg sedimenta.nies.･ lr-'inally, some 90 km, fayther south,"v'hree la]rge bodies ef serpenti/nite oeeuif iiR the Y'ubariJYufutsu-Saru

distriet. wrhey .forni irregz'ilax-shaped inasses, eoveying respectively'b5''i]/twa-;illiE'., <`n) ili:i-F,Il, (ll) tit}ul･--!i}･i"l;-iti>?jx

Vltva-basie Roeks and As$oeiated Ore Deposits of Hol<kaido, japan l81

area$ of approximateiy 25×4, X8×4 and 15×6 1<m. (NEsioTo, etc. Z937). in additiok to these main loealities, numerous small outerops of

serpentinite oecuy as Iens or mass in the Kamuikotan zone, showingtheiy long axes roughly payallel to tke yegional strike of the eouney,

as is the ease in the large masses. The total area wkeye serpentinite

is exposed ilt the Kamuikotan complex fay exceeds in size any o#hexarea where sueh phen.omena are observed in Japan, In general the areas of uitra-basie, espeeially of serpentinite, are

eovered by thiek soil or fanglomeratie materials; exeeilent outerops o£the roek are usually rarely observable exeept at river eiiffs, opon-euts

of asbestos mine anct adits in ehromite deposits.

It is noticeable thatt･he serpentinites contain numerous yesidual rem-

ains of unaltered eonstituents sueh as olivines, pyyoxene$ and spinel

groiip mineyals, indicating that the originai izitrusives were peridotitie

xock. Fyesh peyidotite and the original forr¥}s whieh have novLr been eon-

verted into seiepentinite, ean be elassified into severai types from the

sCandpoint of predominant constituentes aiid their proportions:dunite, saxonite, harzburgite, wehrlite, amphibole peridotite, plerite,

plagioclase-beaying ctunite, ete.

From the petrological natures, these ultra--basie i oel<s ean be divided

into two main elasses, the oRe is eomposed ehiefiy o£ blaek erystals of

serpentinized olivlne aiid bas'titised rhombie py.roxene o£ light greenish

eolour; th.e other is representect by dunite though it o£ten shows eloseassoeiation with augite dunite, plagioe!ase dunite, or gabbroie yoek,

Sharply banded ayrangement ox" these roelg facies is often seeft in a

peridotite mass. M. ]}IvNAHAsi (1950) gives the iiame "Sasame"' type"

to the former and "Hidaka type" to ehe !atter, The Hidal<a type.roekis wldely disti'ibuted not oniy in the Hidal<a eompiex but also in the

Kamuikotan eomplex ; the Sasame type roek is, however, rather small

in volume ln both eomplexes, compared with tke former. Field observations suggest thae seypenti]}isation of the most･of the

oyiginal peyidotites probably resulted from auto-metasomatism duxing

ehe consolidation of the magma as well as from aseending hydrothermalsolution whieh mvist also have emanated from diffeyentiated dike roel<s

which were numerously intruded in the uitra-basic masses themselves,

In general large serpentinite body is massive aixd eompaet though

witk many irregular cracl{s axxd fissures; oftelt it eontains numeyous

yeliet minerals, showing mesh sh'geture. But a small lens or narrow'k' "Sagan3e" inea'ns dKTarf bainboo(sasa)-pat]t,ern.

!82 J. Suzul{ibelt of serpeiitinite has frequently a yude or fine foliation whieh msual}y

eoineides with that of the eontiguous sehist. Reliet mineral is scazrk

or almost absent in it, The fissuyes of massive serpelttinites are o£'ten

fil}ect up by the veinlets o£ magnesite, ayagonite, elayey material, aqua-cyeptite, zeolite, or pee'tolite (HARtyDA 1934). [E]lte pyesence of sehistose

serpentinite would be dependent upoxx the operation of shearing stress

whieh may oecur without obvious ehemieal z'eeonstitution or may yesultmere!y itt the forinatibn of antigorite. Excellent examples of sehistose

serpentinite with a slight liltear arrangement o£ antigori'tie fial<es, arel<nown at the Kamuiyama<i) district, the south of the Kamuiketalt

o£ Val}ey. Some speeiai serpentinites which coiitain considerable amo-

unts tale, phlogopi£e or actlnolite are loeal}y seen Eix the Kamuikotaneomplex zone. They were pyodueed by hydrothermal metasornatismand dynamie aetion on normal serpentini'u'e.

Fresla peyidotitic roeks are mainly known in the metamorphie zone

in the Hidal<a com)plex. Most ox" them oceur as a small mass or sill,but a peyidotiiu-'e mass whieh intyuded in the amphlbolite area of the

Horoman('2) district in Hidaka Province, is eomparatively large, 10 km,

in maximum diametey, In this body, thyee petrographical faeies eanbe recognized, viz., dunite, pyroxene dttnite and olivine gabbro. Through

the whole yoek body, the ehief components show a regulc"tr ayrangement,layer by layer, whieh !s eoiisidered probably to have origina'ted in con-

sequenee of fiovLiage in the magma (HuNAHA$i, 1948; 1950; HuNAiiAsiand HAsim(oTo, 1951;IGi altd BANBA, 1950).

Though the volume is usualiy sma!1, fresh peyidotitic roel<s often

oeeur in the serpentinite masses belonging to the Kamuikotan eompiex,

in the fomn of an irreguiar body or younded mass. An example ofpyroxene dunite mass at Iwanai-d'ake(3) (96e m) on the east side bf the

Saru River<`>,in Hidaka PMovinee is 2kin. in maxlmum diameter; itsmarginal faeies show gradual transition to serpentinlte. The roek iseharaeterised by its eontent of a large amoune of disseminated ehromite-

spinel grains in some pa}rts. Another example is numerovts roundedbloeks of pyroxene dunite, O.1-1,Om. in diameter, in the serpentinitemass of the YamabeC5) distriet of Ishikari Provinee. These biocks usually

have sharp boundary with the surrounding seypen"c･kiite.

Looking out over the ultra-basic roel<s in EIokkaido, no useful ore

mine]rals have been tiowid ip- fres]k perictotite in the Hidaka eomplex

in spite o'£ the ]`iaet t-hat several ore deposits are elosely assoeiated with'(l)'i/ittiii}'ik' ;"(2) 'ip;lt]4ljl'<;li''l'.fliJIA:g':･-f]' (4) -}t})?ftz'Jii, (s) gi'i'i-K･

Ultya-basie Roeks and Associated Ore Deposlts of rlfok}<aido, Japan IS3

in the seypentini'te in the Kamuikotan eomplex.

[I]e su]nmarlse what has been describeCl above, 'the ul'tra-basic roel<s

of "ol<kailclo eaii roughly be elassified by thelr petrographical nature

into five main types, though they are some elose interrelations with

eaeh other: (1) massive serpentinite showing mesh strueture, with oywithout reliet miiterals, (2) sehistose serpentinite, (3) taleose serpentinite,

(4) aetinolite-fels, (5) peridotite, enelosing duni'te, pyroxene dunite anct

ehromite-rich dunite, ete.

The chemieal eomposition of peridotites and se.rpentinites from ffok-

kaido wM be shown as follows £or referenee:

[l]ABT,it I. Peridotites from E[okl<aido

.I I2 .I 3swi 4 5 6, tX 1SSi02

Ti02

AI20a

Fet03

FeO

MnOMgOCaONatO

K,OH20 (-l-)

H,O (-)

CO,

Cr£03

NiO

l'

3g.?,1

l/ l.2,7i

l 4,371l 7.e.7l･ n.d,i'

l PS.S9l 6.s`.),

il Oall4i, O.04]1

j} ].93

if .I:

l

f

4S.,.l6

tr

3.69

2.72

5.1.o>

OA3

3S,69

5. .O,8

O.5S

OJ6

O.75

l'

llt

li)f

L

E

40.ta)O '

t,r

].31

O,S6

4.l3

O.P,S

45,Sl

4,96

n.d.

n.d.

0.44

l gg.74 l/' gg,6g ll gs.og ll'

4e.86 43.2S

tr o.o3 1,S9 5.602.59 i i.72 15.54 i 4,77tr i O.46 145.15 i P,2.SO

'2.72 j, 9,56 l - i O.50 1 H l O.M:I:/,a l] os(}

-1 - lO.17 1i -- 11 pm I -" I t . ttt.tt.t

7,g.s2, I' 4`.).l6

tw I･ H I2.50 I 3.58 [/8.52 [ 9.4S

-I pt

46.65 4･O,25

O.20 l O,50 - il -

O.62 1 O.36

O.45 I 1.95 i -[ - lO,78 l O.7`.,

o,35 I o..o,s

Total gg.47 I 9g,57 i 99.S9 l 99.3S

lE

i

l 43.m

l-i 4,06I g.p,s

40.01

O.96

O.96

O.41.

o.s s,

O.30

99a99

(1)

(2)

(3)

(4)

(5)

(6>

Dunite, Horoshiri-Dake, Hidaka ?rov., (in ffidaka eornplex) Anal. S. HAsms!erro, (HtiNA-

uAsi and UAsiilbiot:o, 1950, p, L'O). ･Pyvoxene dunite (A). Al]oi-dake, Horoma:i, Hidaka Prov., (in T{{idal<a eomplex) Anal, S,

Iu]o 3nd [I]. YA}tix)foTo, (}iuNtui,xsff and nAsin"iouv,, l9i")l, p. 20). '

Pyroxene dunite (B). Apoi-dal{e, Horoman, }{[idal<a Prov,, Anal, S, I(po and [Ir. YA}EtuioTo,

(HuN,xnAsi and H.ssin"ii)rtv, .1951, p. 20).

Hornblende pyroxene dufiite. Apoi-dal<e, Horoman, Hidaka Prov., Anal, S. ffro and{I]. Y.･x"rA"foTo,

Peridotite (Gabbvoie £aeies). Apoi-dake, Ho,voman, Hidal<a ?rov., (in }Iidaka complex)Anal. S. I,ro anci [l]. YA'MA}iofvo (HuNAiiAsi and H"Nsiii]fo'iio, l95'1, p. 20).

Pyroxene dunite (A>, Ixvanai-dake, Hidaka ]?rov,, (in Kamuikotan eomplex) Anal. S.

.184

(7)

<8)

,T. Suzuki

Mt}myi.･N, Meiji Mki. Co.

Pyroxene-dunite (B), Iwanai-dake, ffidaka Prov.,

Pyvoxene-dunite <C), Iwanai-dake, H'idaka Prov.,

TABr,xi ll. Serpe2itinites

Anal, S. MoiauiA, Meiji Min, Co.

Ana}, S. Moi{ta･A, Meiji Min, Co.

from Hok}<aido

Si02

Ti02

Al?O,]

y'e20,l

Fee

MnOMgOcao

NaL,O

K,O

H,O (+)

H,O (-)

Ign. Ioss

1

l

2

I'

l･i

3

I･

II1

I

IlI

i1I

l-

iI･i'iI

ll

39.39

I.45

k,.94

5.60

37.S4

O.sn.

I2.79

l39.37

i 1 Hl I O.99 i

5.l7 l i?t77 ii

l35.61 l ' i e.2s

ww L I13,56 i I 1.19 i'

pt l

3,9.S7

1.00

5.24

3.S2

36.e6

O. 2･S

1 :), Jl3

4i

5 6

Totali

l 100.53

?,7,29

i'

pm j sens 1 7.o.,o, il

2.23 'i

im I2&2o I

O.43 I -/

JL).37 i

:].:,,.n i

1 -nv-- [1･

38.45

?,.24

?.26

5.l6

36.32

O.S7

O.25

12,53

E

I

IIEE

EJ

53.09

3.30

O.89

5.42

4.46

O.28

20,9S

10.49

O.53

O.06

3,04

E99,94 I 1.00.00 I

il

199.45

Fl IOO,OSl

'

I leO.54'

-･<l) Serpentinite. Kishinosawa, Yamabe distyiet, rshikari Prov., (in Hil<aka eomplex) Anal.

H. KoN[sHI (SuzLTKI, l941, p. 26S).

(2i) Serpentinite. Sakaezawa, Yamabe distvlct, Ishikari ?rov,, (in Hidaka eoraplex) Anal.

T. INouir., Hokkaido Univ.

(3) Serpentlnite, country rork of ehrysotile veiR at the Nozawa mine, Yamabe distriet, Ishikari Prov., Anal･ [l]. I'Nou}i (Sv･ztJi<i, and TNouF. I94S,, p. I95).

(4) Set`pentinite. Neay Kanayama, Sorachl-gun, Ishikari Prov., (in Hidal{a complex) Anal.

M. SA}fnoNstJ･Gg Hokkaido Univ.

(5) Serpentinite. Takadomari, Uvyugun Ishikari Prov., (in Karnuikotan complex) Ana}, A.

KANNARr (SiJ,ztTKt, j939, p. 30).

(6) Aeti'nolite-fels, Ilorokanai-pass, Uryu-.trun, Ishil<ari ?rov,, (in Kamuikotan eomplex) Anal.

A. KANN,vii (SLJzi,nt'i, 1939, p. P,O).

It is worthy to note that the serpentinite masses in 'the Kamui-

l<otan eomp!ex are in places traversed by nutmevous dike roeks having

leueocratic or melanoeratic natures wkieh may repyesent later intrusions.

These dikes ave eompaet and hard in usual ease, and projeet into the

fie}cls o}i aceount o£ their g.rea'tey resistanee to erosion, eenipared with

(Jlt/rn-basie Roel{s Rnd Assoeiated O)re l)epos;it$ of Hokkaido, Japan IS5

the surrozmding serpentinite (SuziTm, 1935a; 1939e; l940).

[I]he representati've kln<S{s of' the Ieuteoeratie roel<s are albitite, quar'tz

albitlte, hornblende albitite, quart-z albitophyre, albi`te aplite, anorthosite,

tvendhjemite, pegmatite, niiero-dicrite, dioyite-aplite, gabbro-apl!te, etc,

Repi7esentatives of the melanoeratie iToe}<s a,re koritbleitdite., titawn-augite-

x"els altd diabase. ef these dike roeks, albitkic anct aplitie t-ypes are

mostly seen in Che masses iR E[idaka and Iburi ProviRees, while miero-

dioyitie axxd tyondhjemitie t･ypes are mostly seen iii t"ne masses of Ishi-

kari Provinee. ki Teshio [E'rovhxee, the }ev;eocratie roeks have rarely

been reported, though they may be represented in eertain localities

by dikes of mievo-dioyite is 'traeeable for only a short distanee.

All these leueoeratie a･nd melanoeitatie rocl<s'sliow variations in

cemposition and £exture ; most of 'the elike z'oeks, however, aye believedl

to be gene'tieal!y related 'to eaeh other, indieating that they might have

been differentiated from the same magma, may be related to the ul'tra-

basie roeks and may belon,ff. to a single intyusive series,

[l]he writev has been lei{ by field data to the view 'that 'the origiii

of some leueoerates might be elosely related to the genesis of some

ore deposits, foy lnstanee o£ ehromite, mercury or asbestos, Thae is tosay, these dike yocl<s, ie seems reasonable to eons!.der, inay have been

preeursors ln the mineralisaeioii of these kinds of ore, though they are

not always so (Suzvi<i, 1943a),

In addition t･o the above-iit}entioned dike roeks, rodlngitie roel<s

which ai'e ehiefiy composed o£ g}'ossuralite and diopside, sometimesassoccia'ted with vesuviaRite, are often found as irregu}arly rounded

masses, O.3-3.0m. in maximum diameter, thyoughout the whole serpen-

tini'te area. From the peculiarities in the eomposition and oeegrrenee

o£ the roel<, question ayises whether the mass is a eognate pyodttet withserpent!nite or it originated aeeidentally as xenolit}'itre bloel< in

serpentinite (SvzvK'r, 1940).

As det･aiiect deseript･ion on these di'fferentiated d/l}<e roel<s has

alreasy been published, some data on t,heir ehemieai ana}yses may be

o.f in'terest as follows:

lg6

(E],x.BuE

l

[;, Suzuki

III. "ifferen'tlatedi dike roeks assoeia'ted with serpentinite

manii i'2 I･

i'

31 4' i"

l

5i I･61 71 L

I

SI l

' 11t9 li XO i･ IIt. I･ 12

isio, I iTi02 iAI,O, i

Fe203

FeO

MnOMgOCaO

Na20

K,O?20,:,

H20 (-F )

H20 ( nv )

COg

Ign. Ioss

67.l7

e. p,e

18.22

O.46

O.65

O.06

l.OS

O.92

9,46

e.33

O.92

O.31

'llI

1

[l

I

:ill:il

157.56 l 70.24

1 o.le l. o.o7

l24,96 l6.S6 l･ ' O,2･･4 1i e.l4 l l e.36l OS6 11

pm l tr it O.72 l･ O.73 ! l.sl) 1 o,g2

1 3.6! I '6.85

O.II I l.94 - ･ --: g.62 l. o.g6

I･ O.84 9.48 o,os l/ nd

{ '

7.`-),.92 PO,2J

O,i6 1･ O,52 1i i6.6g I/ i6,7o

iI' O,25 1i O.2,,S

/[ /i･ O.5oI 1.4o

i tr i/ e.22

.1 I O.43 5.27 l1i O.42 ,l 7.23

l 7A3i 6.7S 1 O.tt,9 l O.36

[' - I tr

' O.4S 1i 1,31 l 1 O.20 I･ O.19

,11･ pt I･ - - MI ww

i

EE

I

7o.4s l 6s,s4 I s3As

- li e.os o.lo l･ , l･ i･I6.43 l 17.09 l, 17.S3 o.37 1, 2.7ct I. o.ig)

O.71 1 e.45 I ].O`.)

11 ll O.031 - ili O.05

lt/ ].53 l l.39 i 3.S7

1/ 2.lli 2･.l6 i' l,7,7`.)

tl Ii 4.4P, ii 2.00 I, 2･l2

l.07i l.84 I, O･IO

HI O.5Sj i tr

･1l 11 11 L54I - i L),69 11 - I' - i' O･4S

- ji -i O. Z,5 lj - i 3.l4! - 1'i lt

E

:

l

ItIl

j

si.ii ' 4o.ss

o.isI tr

j4.l 4 i 15.03

o.3s l 3,s6

! 8.91 i 3.90 'i o.2-Si -

7.7S i 4.45 I 1].2A9 l L,6.62 1 !]1:i"I2,]

l

tr i- - ･.J.56 -- l･ o.so

･1- l･ - i

2,sg l -

i

E

l･

[

II

l

EEIi

s's.4?, 1 4g.l2

tr 1 i.oo

i2n..o6 1 i6,44

i [ 1.70 l･ 6.SO 1 1 l.95 I 6.01 l･ - I O.2S i 1 2.41 i 5.75 128.56i 9.00 1.3s l ?,.lt.)

e.34 O.47

Hi tr 2･ .50 ]i - o. io 1 ww

i

- pt ww l ?,66

Totali gg.ss Iioe,o21 gg,gs: ggo7 11 ].oo,i-tob i, ioo.;isi gg.3s i gg.sii

99,S! I, 99.97 11 99,40 ,IOO.65

pm･

(1)

(`-,)

(3)

(4>

(5)

(6)

(7)

(s)

(9)

(10)

(ll)

('l n.)

Albitite, Shin-nitto Mine, Saxu-gun, Hidaka Prov,, AnRl, S. Ko}fAur,sv (Svzr/k-[, 1940, p. 72).

Albitlte (deeomposed). Shin-nitto Mine, Saru-guin, E{idaka }'rov., Anal. S. KoMA{cs" (SvziJig

l940, p. 72),

Quartz albitite, Tanakiiwa, Hatt3 Mine, Saru-gun, Hidaka Prov,, Anal. S. Ko"fArrsv

(SvzvKr, 194e, p. 74).

Quavtz albitite. Bankei-adit, Nukahlra Mine, Savu-gtun, Hidaka Prov,, Anal. S. Ko}fATsu

<Suzvif[, 19ELO, p, 74).

Prelmite-bearing hornblende albitite, Tributavy of the Ugonai Rivev, Nakagawa-gun,

peeshio ?rov., Anal. S, KoM.･s:rh'u (SiJ/zvm, i940, p, 79).

[I]ro:ndhjemite. IIoronari Uyyu-guR, Ishikari Prov., Anal, [I]. Nj･itsio[vo (Su-z(T･Ki, i935, p. I60).

Trondhjen]ite. Kishinos'awa, YamRbe Distriet, Sorachi-gun, Ishilgari ?rov,, Anal. }I.

KoNisHI, <Suzu,it,f, l94e, p. 1`.)6). ･I)iorite-aplite. Eastern Hill gf Toikanbetsu, Nakagawa-.rvun, Teshio Prov., Anal. S.

Ko}I.xTsu (StJ･zvlcl, J940, p. //]71).

Diorite-.:rabbvo-aplite. [l]akadomari-Penke, Uryu-.crun, Ishikayi Prov., Anal. A, I<ANNAll(

(SuzvlcT, ]940, p, l30).

Rodingite (Outer Zone). Kanayama, Soraehi-guii, I$hikari Prov., Anal, M. StN}iBoNsvcii

(Svzt-l<･I, l940, p. 13{I).

Rodingite <Innev Pavt). Kanayama, Sor'aehi-.osun, Isbikari Prov,, Anal. M, Stx]moNsuGi

(Svzvffl, l940, p. I34).

Diabasic melanocrate. Kamuhnura, Kamikawa-gun, Ishikari Prov,, Anal, A. KtwNARt<Sv/ztKI, l939, p. 3C)).

Ultra-bEisie }"ocks and AssQeiated Ore I)eposits of }'Iokkaido, jap' an 187

M CONTACT ME'g"AMORPH{C ROCE,CS RELATED T() rgft{km 'vx.TRAptBAsxc xNmvswEg

lt is noticeabie that various interesLtiltg roeks locally develop betvLTeen

the sehistose yocks of the Kamuikotait eompiex and t"ne u!tz'a-basie

intyusives, whi'ch have attraeted speeial at･tention beeause,o£ the pre-

senee o£ some special soda-bearing" silieates, sueh as albite, glaueophane,erossite, riebeel<ite, erosldolite, aegirine-augite (Suzvi<i, l.932b ; 1932c ;

1934b; 1939a). In additlon to these, some speeial mineyals like lawsonite,

gaynet, piedmontite, sphene, ruti}e, stilpnome}afte, apatite, etc. aye also

included in similar roeks. These yocks are also eltayaeterised by the

assoeiation of numerous veins or lenticles of eaeh o.£ the followingminerals : quartz, albite, epidote, ealeite, aragonite, magnesite, ehlorite,

zeolite, prehnlte, pumpellyite, ete. (Suzuq 1924; 1931; 1.933; 1934e;

1935b; 1938c; 1948a; S{JzuKi and YA"fAGucm, 1933; HA"Ai)A, 1940;Ism-

BAsm, 1939; YosHi)suRA., 1936). '' ' The combi'naLLion o£ the essential eonstituents in the eontaet meta-morphosed roel<s, between normal erystalline sehist in the Kamuikotancomplex and the ultra-basie intrusives, is very eompliea"t'ed, The roeks

may eonveniently be subdivided into many e!asses £rom the mineralassoeiation and miero-str"aeture. Some Cypieal examples of the speeial

contaet roeks may be named as follows:

Glaueophane epidote albi'-'e ehiorite sehist

GIaueophane bearing epidote albite hornb3.ende sehist

Ganiet glaueephane sehist Muscovite garnet glaueophaBe sehist Zolsite plagioelase glaucophan.e sehist

Caieite bearing garnet glaucophane schist Diopslde beavin.o' glageophane epidote ehloyite schist

Aegirine-augita.. albite glaiicophane sehist

Epidote glaucophane quaytz sehisC' Zoisite bearing glaueophane albite quartz sehist

Riebeckite al-bi'te quar".z sehist

Aegirine-augl'te bearing glaueop.hane albite quartz sehist

Garnet albite riebeel<ite quartz sehist

Aeg:,vine-augi'te aiid garnet bearing yiebeckite albite qutartz sehist

La"rsonite albit'e g'laueophane sehist <ve.ined with pimipellyite)

I'iedmon'ti'te albilXte quartz seh'ist

Magnetite bearing ga}'net quartz fels, ete,

(Among the above-elted roeks, glaueophane will 6ften give plaee to

erossite, altd riebeel<ite to erosidolite),

Excellent localities for these speeial roel<s are known at the Kamui-

l<otan<i) Valley, the HorokanaiC:" Pass and Kami-etanbeesu(:)) districts

o£ Ishikari Proviitee, HoJraisan('i) near the town Mitsuishi""' ixx Hidaka?rovinee, anct in the Toikanbetsu(5' dis't･riet of Teshio Provinee (Suzum,

1932b; IsHiBAstii, 1939). The detailed mapping o£ these loealities bymany observers has pyovexx Xbhat these speeiai rocl<s have only a limieed

development in an, area aiong or near a ceytain serpentinite mass and

yarely in a xenolithie bloek within it, though some geologlcal and litho-

logical differenees are Sotmd loeally.

This fact seem reasonab!y to ii>dieate that these speeial yoel<s are

a produe't brought about by eontaet metamorpkic aetion due to ukra-basie intrusion and the oecurrence of the speeial minerals in them

originatect from pyyo-metasomatism, primarily owing to the action o£some espeeially soda-rieh hydrothermal solution derived from the ultra-

basie intrusions, It seems tha't these yocks have originated ki several

distinct ways, vez,, by uralitisation, serieitisation, albitisation, glaueo-

phanisation, aegirinisation, ep. idotisation, prehnitisa'tion, serpentinisation

ete., whieh were probably brought about by the metasomatic efiiect of

emanated solution.

Some large masses o£ amphibolite are kftowit to be izxeiosed in the

ser}pentinite body at the environs o£ Horokanai, Ishikari Pyovinee. With

re£erenee to the chemieai side of the proble}in, ehe roe}< is believedto be essentially produeqd by large seale metasomatism beeweexx theultra-basie rock and later intrusions of gabbroie roek (I{{uNAffAsi, 1944).

Vayious kinds of glaueophane bearing schists somewhat similar tothose of the Kamuikotan eomplex, oceur as pebbles in the alluvialdeposits a].ong the Obirashibe River aRd its tributaries whieh drain the

Tertiary area oi" the Teshlo mountain-land. A eareful examination of

the geology and ehe river systems, has !ed the writer to the eonelusion

that those pebbles eould have been washed ont £rom the Neogene[E]ertiary congtlomerate }.ayetrs in the area (HAcmi¥A., 19e2 ; SvzuKi, 193i),

This fact indieates that the Neogene layers were deposited after glau-

eophane bea].'ing }roeks had been formea by the intyuslon o£ uitra-basieroeks, Althoug,'h a detailest description on the eontaet metamorphosed

('l) 'iii'iitlli}'ili';ll-Sl, (2) f !llljjlllAl, (3) .J:i;/.11-J!}Xll, (;t-) #3IttlJl, (5) llll-#¥J]Ij,

Ultra-basie RocVcs and Associated Ore il}eposits of tlokkaid6, JRpan

roeks of the Kamuikotan eomplex is beyond the seop6 of thisehemieai aitalyses of some erystalliRe schists and metasomatosed

in the complex may be shown, £or referezzee:

TABi.E IV. Silieeous schises in the Kamuikotan eomp}ex

[I

IS9

paper, roeks

l

Si02

Ti02

AI,O,

Fe203

FeO

MnOMgOCao

Na2,O

K,O

P20s

H,O (--)

HL,O (-)

C20

ign, }ess

/t

]S7.96

O.60

2.43

O.69

1.68

3.33

e.47

l.59

pt1.21

A

f> Il

3

i'

84. {I L}

o,b'e

.

6.49

O.S2

2.44

O.14

],,62

O.74

O.97

O.60

tif

l.S4

ljl

l

i/

l

li

Ii'

li'

ll･l･i'

L1lll

i

90,57

O.05

'3.5S

1.ll)

l.07

o.e4

1.25

2.53

O.19

o,a4

O.14

4Il

l5

S4.40

O.53

2.SO

l.IS

l,54

e.42

2.`.,7

l.62

]..30

O.S2

O.50

1,50

O,4:1

S4.19

o.`.)o

4,11

2.77

3.59

O.85

J.S5

O,47

1.j.2

e.97

6 ii

7

'

tt/

s

1 [

76.77 I S5,SO 59.30

- l tr O.2ept jiiO.59 ' k).73 i S.66 l9.{tO l IL70 5.2Z7.lg l 2.6o s.os l･

- i O.28 1 O.12 i1.50 I 3,OO 9.37 - 1 !.o.o i.2dla'.7S li 1.9e 6.11e.os l o.s6 e.ssO,k,6 i' O.31 --- l

1.14 i - ].4`.}

- - O.32 w l o.to ww :

-l- -(1)

e-))

<3)

(4)

(5)

(6)

(7}

(s)

IPota1 , gg,g6 I ioo,3s l, ioo,gs l gt).:)L) i/ ioo.ig.) 1, gg.x l･ ioo.4s I' ioo.6o

maemmuwwtr rm Albite-bearing glaueophane quartz sehist. Horokanai-pass, Uryu-gun, Ishikari Prov,, Anai.

A. KANN,sRI (Suz(JKI, 1934, p, 2･4).

Glaueopbane quavtz sehist. Horol<anai pass, {LJryu-gun, ishikari Prov., Anal. A, KA.NN.Nki

CSuz(JKI, 193,4, p. 24).

Glaucoplmne quartz sehist (Garbenschiefer), Horokanai-pass, Uryu-gun, Ishikari Prov., Anal,

T･ NAKAyAMA, Hokkaido Univ. Garnebbeaving albite glatieophane quartz sehist. E[orokanai-pass, Uryu-gun, Ishikari Prov.,

Anal A. KisxNfv･u (StJzui<i, 19/39a, p. 516>.

Riebeekite-bearin.: albite quartz schist. Kamietanbetsu, Kamilcawa-gun, rshil<ari ?rov.,

Anal, A, KisNNtva (SEJ･z{.J･Ki, l933, p, 61S).

Aegiyine au.ffite-bearing riebeckite sehist. RaiYroad cuttin.cr near Kamuikotati station ,Ishi-

kari I'rov., Anai. A. KisNN:v{T (Svzum, 1933 p. 618).

Aegirine-augite-bearing glaucophane quartz schist. Pebble found in Neogene Tertiavy

eonglomerate at the Obirashibe River, Teshio Prov,, Anal. A･ KANN2sR[ <Suzvm, ll.93], p.

2S5).

Glaueophane (mineral) froin glaueopi]ane quartz schist. Ilorokanai-pass, Vryu-gun, Ishikari

Prov,, Anal. II', Ni-]MoTo (Suzu･Kf, .l93,9a, p, 5'l7).

i90 J. Suzuki

TAisi,E V. Greeitgehists in the Kamuil<otan eomplex

Il

zEIlt

2 3 4 5

sioll

TiOfi

Al,･O,

p"e203

FeO

MnOMgoCao

Nap.O

K,hO

P,}Os

u,o (-l-)

U20 (-)

Ign. }oss

ii'

ii:iltll

{S2.l.6

1.90

l3S5

5.e `.'

lj.74

O.l5

II.03

9.47

2.00

O.14

1},61

4S.56

2,50

le,go

9.31

6,25

0,15

2.94

ll,.61

1.24

O.23

O.11

li.IS

l

l

i

50.S8

O.75

i3. k,9

i.67

8.60

o.o.s

S.7S

S.99

3.62

O.3S

tr

3.eil

II

I

i

IL

ll

l

48.88 l 46.72

3.90 i 4.0S

13. 44 l. 5. imo

5.3,2 l 4,02

S.96 i 5.12 tr I o.ib'a.2i l 7.`.)3

I･5.SO 9.IS I3,73 l 3.{m

1.71 j･ 1.50

H l o.2Et i3,,40. ･I 5,.12 IO.S,6 I O.07

6 7

44,36

2.42

l4.S4

12.01

5,45

O,17

5.44

S,62

2.26

O,93

O.24

2.72

O.IO

EEI

se.3s

2.S8

8.90

X,.17

5.9S

O.l7

7. ,.)5

10.36

4.65

O.67

O.25

l,9S

O.74

8

l

ij

Ii

48.79

O,5S

9.Z)5

7.44

6.26

e.19

fa,.87

9.76

7.34

O.50

o.al

5.7k}

1.24

Total i ioo,o7 i gg,gs i ieo,2s l gg.7u' l ioo.s.)3 , gc}s6 l.eo,3s leo.`.)s

(1) Glaucophane-bearing amphibolite. Horekanai-pass, Uryu-gun, Isbil<avl ?rov., Anal. A.

KAtsTN.v-,I (Svz(Jrc[, l939, p, 1,7).

('"') Epidote gla.neophane srhist, Horokanai-pass, Uryu-gun, Ishikari Prov., Anul. A. K,･sNN.uu

(Sv･zuix"r, i939, p. "'J7).

(3) Diabase setnist. Neav Harushinai, Kamuikotan Valley, Ishikarl Prov., Anal. A, K:sNNAm <Su･z{J･Kl, l939 p. 27).

(i2) Epidote glaucophane sehist. Kamuikotan Valley, Ishikari Prov,, Anal. H. S, Washingtoti

(Am. Jouif. Sci,, 11. i901, p. 35).

(5) Gaynet-beavin,rr. aegirine-augite lavLisonite glaufiwophane sch'ist (with pumpellyite). Navu-

shinai, Kamuil<otan Valley, rshikari Prov,, Anal. A, Kl:xN.s･xn[ (SvzuKi 193S, p･ 237)J

(6) Aegirine-augite albite epidote amphibole schist, Hovaisan, near Mitsuishi-towrp, Hidaka

II'rov,, Anal. M. Isr{mAsm <IsiiiB.ssui, l937, p. 44S).

(7) Aegirine-augite bearing diabase (A). Hakkin-zawa, Yubari-distylet, Ishikari Prov.,

Anal. S. Ko"m'c;)'u <SvziJKi, 1939, p. 30).

(S) Ae.ffirine-augite beaving diabase (B). Hakkin-zawa, Yubari-distriet, Ishikayi Prev., Anal. S. Ko}ittu]su (SuzuKi, l939, p, 3'O).

XV. OftE DEPOSKTS ASS()CXA[M'EI) Wllrcff SERPENTgl'iNi"]E"E

Tlte ultra-basie roeks in }Iokkaido are not only of interest geolo-

gica}!y and petyologieally, but they aye of special importanee beeause

o£ the assoeiatec'I depos:,'ts o£ various kinds of usefu} miiierals, sueh aschyomlte, p}atinum gi'oup mineval, ehrysotiie asbestes, meycury, nlel<ei,

copper, ete, (Suzu･Ki, 1936; 1949; 1950a).

l'Jlt,ra-basic Rocks aiid AssoeiRted Oye Deposits of i{bkkaido, ,Japan 19'I

A. Cl-ll<OMITH DEPOSI,[rS

[l]he }lidaka-Iburi distLrlct in I{okl<aido and the distriet on the [E]ott･ori-

O}<ayama-Hlroshima boimdaries in south-western Japan undo'ub'tedly have

}ayge reserves of massive ehromitie in Japan, though some remar}<ab}ediffierenees betvLreen them in respeet to the ehara-eters of ore deposits

appear (Svzvi<i anC{ Isim<AxvA, 1939;Ismi{AwA, 19<LO; BA}fisA, 1951). A

notieea-ble £aet is that nea-r}y all of the lode ehromite deposits arerestrieted to a small'ayea in both distriets, and exeept for some small

deposks, no iode deposits of ehromite is knowlt in othey plaees, in spite

of the known existenee of eompaxatively iarge serpentinite masses,

Up to the present, numerous loealities o£ iode ehromi'ee have beeiifouiid in the serpentinite area in ffol<}<aido. Few of them, however,

eoiit･ain ehromite of gooct qxiality; and as theiy output, too, has been

extremely smal'1 in cluantity, the dist.vlets whieh have been zindey pro-

duet-ion are but+ £ew. Among them aye the I'Iatta,`-i> Nitto,`･`') Shin-nitto,`･i])

IEIat'ta-Usappu,`･'j) NiikahiraC-5) deposits in Hidal<a ?rovinee, Yawata,(")

Gampi,(･7) Ni`it･aka,`") Hobet･su`"' deposlts i.n Ibuyi(i") Province, and only

the ShimpoCii) deposi'te in Ishikari Provinee"f (SvztJiq 1943b; Suzum and

SA}[BoNsuai, 1939). The larg'est deposit not only in Ho}<kaido but in all

Japan is the Hatta deposit in Hidaka Vrovinee, thougli 2t produees acomparatively low grade ore with 41-42 pevcent CrtO,s aitcl it is now

almost eompletely worl<ed out, It appears that the Hatta ore bodywas a fiat lyiiig pod, and the bot't,om of it was eut off by a fault,'i:*

In geneyal t･he massive variety of chromite ore o£ Hokl<aido iscompaet though is often highly shattered, with blaek or brownish blael<

in eolour;it is composed of an aggregation of erxished ehromite frag-ments wi`th a thin opaque border, the eracks in whieh are usuaily filled

up with fine grains oir flakes of uvayoviLe, ehrom-oehr aiad kaemmerelite

(SgziJww, 1942a ; 194-3b, HMtADA and IsmBAsm, 1940, Ii{AitAr)A, 1943). The

massive ore in Hold<aido is mostly, if not a}1, of extremely high grade

eontaining more than fifty pereent Cr,O,i. If this is the ease, 'the pttye

* 7]he to'tal prodttction of mas$ive ehromite, earrying 4e-55 pereen't CrL]03, in the }iridaka-

IburS distriet, from 'l925 to l.945 was 3{)3,02･'7 metrie tons, eorvespoiiding to about 45

peveent of £he national total.'>:'X It is sa'id that the aggregate tonnag"e o'f ehromite oye in the Uatta mine to'taled about

]SO,OOO metvie tons /Erom one ore body, duri/ sr 't･his twenty yeays ; the maximum yearly

produetion o'f massive ore was '.'.2,37:' metTie t,ons in I939･ '

(1) iix.R'l, ('/)) l-l}lt'i, (3> eeellJll, (`l> f'N.l-}l]Ci-1[:re･,f, (s) /"l･lt:･IS-, (6) iK.EIiit, (7) X-l･;ittL-, (S) getl','-1･,, (9) i,,ff.l,3iEj,

<10) jjtst'ec, (11) 'iiili;K.

]92 [i. Suzukiehromi'te would be very high in Cr.O,i, inasmuch

ties o£ silieates are eontained in the ore. Chemi.eal a.nalyses of ehromite and its ore

Ho}<kaido are shown as £ollows :

TAm,E VI. Chroinites and ehromite ores

as eonsiderable quaiiti-

t'rom some places of

from Hokkaide

j

l l 2I[i'

?t

crtO,l

FeO

Fe203

Al,,O,s

SiOL'

MgO cao V{fLO

-..o tpgrs

Tota}

ii 51.211

i i9.?,s

l/ k),57/

il 15.?,6l

l O.55ii ll:.i34

, kw

l ioo.4i

I 55a72 1 L I I･ g.o.1 1 I I 2.14 1

l l7.6;l

1 o.4g l l･ l5.4,l} l

o.07 I-

iHI...L..= .. . . Ii

i IOO.6s i

57.00'

lg.sg

5.85

7.10

C).64

9.A+9

O.07

4

l･

i

I5

i 55.6i. I' 53.26

I 7.56, 1 lt3,09 't pm l 1-l･ :),i).s4 F 6,s3

'

I -- ]?.l3I - l 10,5P,I,I/ltI - l 4,oii - i o,?s1 ig I-1' 'i'

100.03 I 99,OI loo.go

6

59,55

13.29

6136

2.26

l6,2)7

OJO

97.83

7 ll 8･

1

59s12

IS,25

S.IS

7.S3

6.60.. 11

L 99.gs i

'

49,40

17.93

9.07

l `.,.32

2.00

9.6e

jOO.36

(l) Chvomite (Chrome-pieotite). Nishi.ffami Adit, Nukahiva Mine, IIidaka Prov,, Anal･ J. KiFr.xfiAnA (KiirA}iAR.･N, l949, p. 27).

(`.') Chromite (Picro-ehroiT!ite). K'asuga Mine, Ibuvi Prov., Anal. J. Ki'ivviA.nA (K[TAyARA, 1947,

p. 2･ 59).

(3) Chvomite (Beresofite), No, 6 Adit, Nitto Mine, }l{idaka l?vov,, Anal. J. K]'vAinyta (Ki'rAiiAzz,

l947, p. 260).(4) Chromite ore. No. I2 Adit. Shin-nitto Mine, Hidaka Prov., Anal. Bureau of Mine, Sapporo.

(MunivvA, l93c"i,, p. '250).

(5) Chromite ore, Zuito Adit, Shin-nitto Mine, Hidal<a l}'rov. A.nal. [l). NAkh.･wAsfA <Suzvm, l943a,

p 59).(6) Chromite ove. Shinpo mine. Ishikat'i Prov,, Anal. Daido-seiko Co. (Si.Tzi'i<i, l943b, p. 52).

(7) Chromite ore, Pankeiyapteushi along the Mukawa River, Iburi Prov., Anal. T, Yosim

(Ishlkawa, IS96, p. 1`1'7). . ･(S) Chromite ore. Pankemoto along the Mul<awa River, Iburi Prov., Anal. T. Yosll[i (Isiu-

KAxvA IS96, p. 127>.

The massive ehromi'te deposits in Hokkaido oeeur as iens, vein, pot,

peascod--mass or fiat-lying sheet in £oriin, usual}y aeeompanied by de-

formation and faulting beeause of thrusting'. The oute℃ops of the orebody are often f'ound at eliffs or in roeky stream bottoms. The bounda-

ries between ore body and eountry roek where observed in the mine,are usually veyy sharp, 'though in some places massive ore grades out-

ward into the noymal serpentinite 'through a more or !ess thin dis-

IJItva-basie Rocks and Assoeiated Ore l)eposit,s o'f Hol<kaido, Japan 19?,

seiininated chyomite oz'e zoiie. The wall roek o£.£ke massive ore iso£ten veined with ax'agoRitte, magi}es:,te, zeolite, pierolite, chrysotile oraquaerept･ite and is visually eharaeterised by the assoeiation of mueh

'taleose and clayey materials.

A dissemiRated chromits ore is often £ound in eertain'plaees butthe volume of lt･ is usually small eompared with the massive type.The yough disseminated ehromite ore in peridotitie roek or hard sez'-

pentinite is rather rare in Kokkaido and some samples from Yuwanai-dake(i) and the [l]omiinoto-Shizunai<:) inine iii Hidaka I}'rovinee are iow

grade earrying only 10-20 pereent Cr,,O,,. They may be eompared wi'th

soine oeeuryenees in the Tottori distriet in south west+ern ,iapan,

At the ZuiCo`'"' ad.it of the Shin-nitto"'i> mine, and the Nishigami'"K)

adit of the Nu}<ahiya`(;) mine of Hidaka Provinee, massive ehromi'te ore

bodies eut respee'tively not oiily 'the serpentinite but the differentlated

dikes of albititic rock in serpentim'te and partally enelose small bloeks

o£ albitite and serpen'tinite in the ore bodiies themselves. The mannerof the oeeurrenees indieates that the origination of massive ehromite

deposits was later thaB int,ru$ioii of the leucocratic dil<e roeks (Suzmq

194-3a>.

The genesis of ehromite deposits has long beeii diseusseCl by many

geoiogists giving rise eo vayious opinions whether it originatect unde}r

orthomagrna'tic oy hydrotherma} eonditions, From the mairy field datain Hol<kaido, the writer inelhkes to eonsider tltat the ehromite grains

whieh had £ermerly aecumulated as erystal mush ln a }owez' semi-eoftsolidated magma, weye earried upward in solid masses by hot si}iee-

ous solutioii aseending along t･he weak part in the uKra-basie mass at

the hydrothermal st･age, aiid formed various kinds o±' oye body undervariable conditions. It appears that the erysta}s of ehromite vLrereerushed into irzzeg'ulay minu-ie fragment･s by mutual eoliision during

the aseeiiding process (Suzui<i, l943a).

[I]he writer expresses his sineere ehanks to [Prof, I!]. SA}f},soN of the

Prineeton Univevslty, with whom he visited the ehromite inines of Hok-

kaido and who gave valuable suggestions to the writ･er on the deposits.

B. PLACER CI-IROMITE DEPeSITS

PIaeer ehromite deposits are widely found in the areas along streams

whose headwaters arise in the serpentLini'te inasses espeeia}iy o£ thenorthern hal:ff ofi ce.ntral Hol<l<aido. Such deposi'ts are found in regions

(I) hl'ld-IAg-l'l-T{･, (2) 'e;i;tlrs;i･lj,-l IA], (3) :-EhllAlr, (Lt) ge?l-lii{, (5) iJEi'A'iili, (6) n･S{-[･P.

194 ,i. Suzukiwkere no lode cleposies at'e 1<-nown. Aiiuvial materlai, mostly derivect

from serpeneinite, is found both in the present streams and on terraees

2-5m. above the stream levei. The 'terraees are eomposed of soil, peat,

eiay, sandy elay, sand and gravel, though p.eat and gyavel oy one of

theixi aye absent in eeytain Ioealities. Bed-roe}< or hayd-pan o£ theallvtvlal cieposit lies at varying depths 1-3m. beloK7v the surfaee of the

grouftd. The bed-roek is eommoniy eomposed of sedimentaries of Plei-

sCoeene or Teytiary age and often serpentinite (Svzum, 1942b ; 1943b),

IY{any mining areas ltave beeit exploiCed in Teshio, Kitami andIshikari Provinees. The areas in the first two provinees, are situated

in fiat eountry, into whieh the waters of the Teshio and TorabetsuRivers(i) and their tributaries eventually fio"r, while the areas in Ishi-

karl Provinee, an along the Uryui River(L'> aRd its tributaries.

ki the alluvial deposit, chromite grains eommonly aeeximulate inits Iowe/ half the yeeoverab}e amo'unt va,yying from 15-20kgy, pereubie me'ter':`. Minute amounts of iyidosmine and natlve gold grains,

o£ten but not always, oecuy in the lowest hoyizoii o.v on the bed rocl<.[I]hey are mined as by-px'eCluets if "hey exttst in sufficient quantities,

Samples of eoneeiitrate eonsist of minute gyains of chyomite, most of

them }ess than 1mm. in size, showing plentiful isolated erystals witheompletely or rounded oetahedral form. Usvially plaeer ore show higher

grade, Cr,S3 45-58 pereeltt, than massive ore, though sometimes it is

high hi iron-oxide eompared with CrilO,s, probab}y owlng' to the large

amount of admixed magnetite impurity.

It is eonsidered that the placer ore has eome, not f℃om the detritus

of lode deposits, but £rom the aceumulation of the sma}} quantity o£aeeessory ehromi'te whieh is always pyesent witli magnetitte as roel<-

forming minerals ln ultra-ba,sie intrusives. Plaeer ehromite is oceasion-

aily S'.ound in shore beaehes of Teshio Provlnee, but i't is ttsually very

fine anCl in iow coReentration. As dian exeeptional ease, the plaeer in

the Numata`-'i> dist･riet of Ishikari Provinee is eonsidered to be a re-

vtror. ked p.roduet, whieh was washed out from surrovtnding NeogeneTertiary sedlmentaries of, the distriet.

÷:' The total proauction ol'e plaeey chyomite, containing 45-55 peveent; Cr20:s, in Hokkaido from

192tt to 1945 was L'e,,175 metric tons with inaximuin annual productioln o'f 5,711 me'tric

tons in 'l944, eovresponding to about a quarter of that of massive chromite in Hokl<aido

in the same yeay. The Horokanai-Tsuehiya(･'i) mine, th.J largest plaeev noxv operated in

Japan, has shipped 5,763 me'trie tons of plaeer chromite vLiith a maximurn L',100 inetric

t,ong in l943.

(]} ]<legen..]ilNaj.l{5]ijjil, (2]) klg}ig]li, (3) ?"Vil, (4> l P;ehiliAlat.･a,.

Ultra-basic Roel<s Eind Assoeiated Ore Deposits of ffokkaido, Japan l95

C. VLACER I.RIDeSMXNE AND NATrVE GOLD DEPOSXTS

it is mos't probable that platinum .crroup metals usually oeeuy in

uih'a-basic int･ruslves, but no lode deposit o£ the metals is l<nown eitherin Hokkaido or iii any payt of Japan, As previously stated, sueh de-

posits of platinum group metais are always found ii} extremely mimiteamoui'}t, a's a p.lacer i]ridesmine, in the }owese par't or on the bed-roek

of plaeeif chromite bearing alluvial dep. osit which iA iioythern Hol<kaido

develops surround or near the serpentinite masses. Also the loca}ity

of placer iridosmine usually co2ncides with ehat of placer chromite,

though the reeoverable part of the £ormer, is yather restricted in itsdistribution. As in t'he ease of placey chyomite, the miiiing of placer

iridosmine has been mostly earried out in numerous ayeas along the

Teshio, Uryu, and Tombetsu Rivers and their £ributaries as well asalso on the shore beaches o£ Teshio Provinee. The Takadomari<i" disgrietalong the Uryg River(L" is the largest produeer; the ground is said to

yie-ld about O,3gr. or less of iridosmine per square metey oza the bed

roek. Seventy percent of the tota} produetioz} fyom Hol<l<aido has been

minect fyom the ayea along the Uyyu River'i` (Suzui<i, 1950a; WA'"!sE,

' Most o£ the platinum group metals reeovered in the plaeer depositsiR Hokl<aido, is in the form of iridosmine erystals whieh eontain iridium

and osmium as the esseiiX-.'lal componeitts (IsiimAw.L, 1895), Real platinum

is exeeedingly rare iii the pl,acer, b'at some varieties ot' iridosmine giTain

from Niseparomappu in ehe Uyyu distriee and otkers eontain abouttwenty oy more pei'cent of yuthenium and are listed a$ ruthenosmlridium

by S. AoyMiA (1936),

The lsolated grain o£ iridosmine is light gray or whltish gray withmeealiie lus'ter; it is less 'than e,5mm, in size in irreguiarly rounded

form though often it shows fine erystai form with the faee o£ c (OOOI),x (22M43) and a Ck12'O' ) (S,NKua,Ni, 1949). Aeeordiiig to Y. SimiA)A, arounded coin-lil<e gr=ain of iridosinine whieh was foun6t at [E]al<asLi of

Ishikari Provinee reaches to 9.4125 gy. and is said to be the Iaygest

one ever £ouncl in Japan, though it combines a min"te amount of }iativegold grain in i'tself. It is generally recognizable that the farther the

loeality is situated from serpentinite body, the finer the grain of iridos-

mine beeomes,

"" P'rom 19k'5 to IY45, the total produetion of ividosmine in Hol<kaido, was about 164,4kgr;

its production reached a peak of 22,,074gr. in ]944.

(l) (l}tt'?EI, (L)) r[･lg'i}gJii.

].96

Theform iit

J. SRzukl

ehemieal analyses of tMhe platinum group metaIs found in

Hokkaido are tabulated as £ollows:

TABms VII. Platinum group metals froxn I{okkaido

plaeer

1.

.l

fa)

'15e.9S I I-33,OS

tr

[ I 4.4`.) i11 .5 `2

3

rif

Os

Pt

?d

Rh

Ru

Au

Cu

Fe

Al,O,

Fe203

l

lIi

I

Il:1

l

l

It54.13 I2g.2,o, l'

i l.66 i

l.73

4,44

i ty

l.29

7.33

l

43.10

3S.4S

tr

5.90

l2.52)

{i i5 l6

../`is.31 1

13s.oi. I'

o,51 l

t, I /i..eg 1

i4.7o I

-I

i

-l I wr I･ I

7iSi -], /

9

i49.80 Ib7.3e I

IL!5 i

3.9L,

7.60

O.02

o.oi

o.og.

0.76

45.49 i･ i' 3.b].S5 i

i. bn I

tr l 1 6.Y,6 I

12.6s l

- -I-I

b}9.(}1.8

?S.S95

O.98S

21..OSO

Il!

:

i

l

I･

I-

I

i

38.`.)3

37.65

1.Sl

O,87

O.51

21.03

Total gg.sl l loo.oo ioo.oo1 ioo,sgl gg,72 I,99.62 Tt'gg.gsil ioo.oo l/

1/ //

l6.7g

h)3,64

d9,32

O,38

6.14

3.74

loo.oe

le

4S.90

51.10

pt

pm

100,OO

(1) Iridosmine. Furano-mura, Sorachi-gun, Ishikari Prrov., Anal. Buveau of Mine, Japan (MATsu"foTo, 1926, p. 743).

(2'>) Iridosmine (Fine grain). Takadomari, Uryu district, Ishikari Prov. Ana}. Bureau of

Mine, Ja,pan (MA!{tsiJ"foTo, l9L'6, p, 743).

(3) Iridosmine (Coarse grain). Takadomari, Uryu dist･rict, Ishikari Prov,, Anal. Bureau of

Mine, Japan (MAfpswMo[ro, ]926, p. 743>.

(4) Iridosmine. Kita.mi Prov., Anal. S. AoyAAtA (Iw.･xsAi<r, ]917, p. 159).

<5) Iridosmine. Takadomari, Uryu distriet, Ishikavi Prov., Anal. Sapporo Bra.neh of the Mint

of Japan (Zoheikyol<u),

(6> Iridosmine. [l]oil<anbetsu, Horonobe mura, [I]eshie Prov,, Anal. R, [VAie.x}iJssm ([I]ArcA-

llAsill, 39(Ll, p. 590).

(7) Ruthenosmiridium. Nisepavoinappu, Uryu district, Ishikari Pyov,, Anal. S Aoy.kAffs (Aoy,s}I,s, l930, p. 7S),

(s) Ruthenosmiridium. Seiwa, Uyyu distriet, Ishikari Prov., Anal. R, [l]Aicfmissm ([l]AKAi-iAsiii,

l94I, p. 590).

(9) ?latinosmiridium. Takadomari, Uryu district, Ishikari ?yov,, Anal. Bitaehl Min. Co.

(WAT:xsE, 1927, p. Je).('IO) I'alladiplatinum. Toil<anbetsu, Horonobe mtira, Tesbio I'rov. Anal. R. IlrAK.･viAsm <TisKA

}iAsm, l941 p. 590).

The plaeer deposits exlsting at some plaees in north-easterii }Iol<-

l<aido, have dez'ived their iridosmine g±iains })y the reworl<ing of the

Neog.ene Tertiary sedimerks, espeelally e£ co]iglomexates whieh aremainly eomposed of iiltva-basic materials. Examples are seen in the

U}tra-basic R,oeks and Assoeiated Ore Deposits of Hokl{aide, Japan lg7

ayea a･long the Obix'ashibe R2ver(i) of Teshio h'ovinee,

Ilt the plaeexr ehMoiinite anCl iriClosiiiline deposits, some q.uantities of

fizze native gold grailts usually oecwr as by-pyoduce of base metal minig

operations. Y. S}ii.tsfAD2x's inves£igatiorm in n℃tmerovts loealit･ies, shows

that the yatio o£ gold grains to iridosmine grains in weight is }ocallyvariable, ranging fyom 5:95 to 9e:le. Fz'om a detailect examiltation

o.£ the }'iver system, lt ean only be stated tha･t the p}acer gold probably

eame £rom the seypezitinite mass, simiiarly to the plaeer iridosmin.e,but it is impossible at preseiit to eoRjeetuye what may be the exac#

souree o£ that gold, [l]he wx'iterr is partiev,}arly inctebted to Itl[r, Y. Sm"fADA, the fourmer

ehief engineer of the Hokl<aido Plaeex ?la･tinum Exploitational Company

whose extensive and valuable knowledge of tl}e iridosmiiie cleposits of

Hekl<aido has been genexously shayed.

D. Cl-IRYSOTILE ASB-STOS DEPOSiTS

In ffokkaido, except £or a smail amount of in£eriour amphiboleasbestos proeuced only in the ShinjoC'i' distrlc't neay the Kamui}<otan

Valiey, eompa℃atively little asbestos woyth exploitatibn has beelt found.Howevei', sinee 1937, when ehrysotile asbestos, appearing to be the best

o£ the kind produced in Japan, was diseovered ln the serpentinite area inthe Yamabe`-i" azid Nunobe('' distriets of Ishikari Pyovinee, there have been

found many kinds o£ asbestos in other serpentinite areas (Suzui{i, 1941). Among the asbestos diseovered yeeei>'tly in varlous loealitiies in Hok-

kaido there are both chrysotile and amphibo}e with anthophyllitie, tremo-

litie or aetinolitie Rature. The sorts which can be actually used a.t'e

merely a pa,rt of the formez'; the lattey type, though pz'oftuced invarious plaees, is inferloy !n quaiity, smail in quanti'ty and not recog-

nized as eeoitomically valuable at present, The plaees known as ehryso-tile asbestos producing dist･riets in ffokkaido are as follow: the Yamabe,(S)

Nultobe"]' and Horokana･i`-') distriets of Ishikari Provlnee, the Usappu,CS)

ShizunaiC"> and Mitsu.ishiCg"' distriet･s o£ Hidaka Prov2nee, ete.* O£ eourse,

":' OE these districts in Hokkaido, those whieh are already u,nder pyodiuction aye the Nosawa, Yamabe, and Nunobe mines in the Sorachi distvle't, 'tbe Asahi-Usappu"i) mine h} the Usappu distriet, t･he Ura",a(･W) mine in the Sbizunal distvict and tbe Tobf}'ts'a(i3> mine in

'the Mitsuishi dis'tvict, The total produetion o/if chvysotile from Hoklcaido [for 1942-･l947

was aboxit :'4,i)OO me'tvie tong with apnual pk'odtL'iction from about 1,500 to S,200 metric tons, ?rior to l9;ltl･., Jap･an iniport･ed practieally ail the. ehrysotile she needed, but in this

year snbstantial produe.t,ion o/e c･lu'yso'tile., exeepL erude elass, began in Hokkaido.

(l) ijvli･･f.ltt.jli, (2)) ssti]jgE, (:i) lh,i'llg, (4-) IIiil'l:, <b) Iiil'l,K,. (6) 7i'lj/i?lg, (7) iPj{LjjmJtl, (S> )f..ililkkl:, (9) li,fti-e]Ag,

<10) E)llf, (11) i,lilEH'JfVli,IJili:, (12) lil!jmp]l, (l3) lil,'ji].

among these dish'iets, theve aye plaees where the product･ion has not

yet been unde}r'taken, sinee only small exposures o£ eh±'ysotile asbestosare l<nown, The laxgest producer 2s the Yamabe distriee, where theNozawa,Ci) Yamabe ancl Nimobe mines are situated. At present, pro-bably 95 or more pe}'cent of the elkrysotile produetion ln Japan is from

ehis area.;':`

The ehrysotile varieey of asbestos occuys in each loealitty as narrow

traeeab}e veins whieh ar]range irregula]ily in usual cases, buC often

predominantly extendlng in a eertain direetioit, oniy in the extyeme!y

serpentip-ized pa]rt o£ 'the ultra-basie int.rusives. Although the ehrysoti!eof the Yamabe distriet is sim:,lar eo the best asbestos of Canada aitd

the longest fiber £ound meastwes about 3em., it is most･ly shoyt being

o£ g.rades Ioweir than 5D on the avez'age. The harder variety £romsome p!aces in Hidaka ?yovinee is eonsiderect to eentain rninute partieles

of talc fil}ing up the spaees among the fibres.

The ehemical eompositions of eh]rysetile veins, and picroli'te vein

whieh is iniimatly assoeiated with ehryso'tile veins in every loeaiiey in

Hokkaido, are as fo}lows:

[l]AisTJi£ VLUI. Chrysotile Asbestos from .Hol<i<a{.do

mu mx- l.

2

sio,

AluO:s

Fet03

FeO

MgOCaOH,}O (i-)

H,O (-)

FI 39.{)O

O.S2

6,07

5,,47

36.07

O,2)2

l3.07

l.al

lii

l

I

i

I

l

)J

39.ta)9

1.9S

5.63

3S05

l.56

13.7j.

3 4

40.08

1,5S

fu).29

Z.S7

40.65

13.76

!

36.94

1.52)

6.IS

39,76

O.IS

14,72

5

l

iIiiI

llill

i'j

40.99

1.tt'3

1.49

2.74

39.77

e.ls

12.S9

O.95

TotalIll

loo.1`.-)i' ]OO,91)

I･

l100. L)3

ll

99.30 T 100.3d

(1)

(L,)

(:)))

<1)

Chrysotile asbestos. Sakae-zawa, Yamabe district, Ishil<ari Prov,, Anal. [r. I>ioup:, Hok-l<aido UBiv.

Chrysotile asbest･os. Sakae-zawa, Yamabe dis'triet, Ishikari I'rov., Anal, E{. Ko.Nism(Sl;･zT}Icl, l9g'l, p, `.)6S).

Chrysotile asbestos, Sakae-zawa, Yamabe district, Ish'ikarl Pyov,, Anal. H. KoN(s}ir.<suzyK･T, .l.9411 p･. 1;l,.l}8>･ ... "

;j.ih'

e. Nozawa iRine in the} Ya}nabe. dlst',riet is the larslese one, Rot; only in I'Io'1<kaido but

in Japa,n, and its product/ioi/t Teached a peak of 5,755 ]netvic tons hit ]9･tEl.

Ukya-})asie R,oelgs and Asgoeiated Ot'e Derosits of r{fol{kaiclo, Japan 199

(t2) Chrysotile asbestos. Og.uvose-zaw･a, Nunobe Distriet, Ishikari I'rov., Anal. Y. K""iAivsu-

z.sK'r, Nippon Sekimen Co. (5) Pierolite. Sakae-zawa, Yamabe Ii}istt'iet, Ishikari Prov., Anal, [l]. Ixozii?. Hol<kaido Univ.

Eveix iik a single serpentLhkite botly, the vein of ekrysot･ile does

not develop uRiformly: biit is limited to a parh"eular part, foriningrieh zone or lens in the body, best suited to open-eut nAi･etLhods oi" mining.

In parts virhieh eontain many veins they gyadually diminish in propor-

tions, and ehange i'nto parts whieh do net eontain any vein at all. Tke

rich zones or ore shoots vvrheye ehrysotile veins deveiop elose together,

extend in similar direetion and are usually subparallei to the elongated

direetion of 'ehe serpentinite body (Svz-<i, 1946a), It 'i a$ been polnt-ed

out that the oceuryei'tee o£ eh.rysotile vein may show intimate .relationwith the jointL system whick was originated duning the eonsoiidation of

the ultya-basie roek (S.gfvo, 1950), To l<now the direetioii and dip of the

rieh zone is import･ant in prospectlng as well as in miiiing oyes. For.

instanee, several rich zones have been reeognized in the 'Yamabe dlsh'iet

where the la.vgest one is 100m. vgTide, 30em, or mox'e long and a'ttai'ns

to the depth of 80 m. oy mo:,-e, dipping 450 eastward.

The eondition of the developmen't of asbestos vein iii the serpenti-

ni`be mass ls somewhat variable;in the ease o£ working tlie rich zonechiefiy, ie is estimated t･hat 2--4pereeRt, and 6-10pereen't i,n very good

eondition, of ehrysotile fiber can be obtained from the roek, In a new

quarry, however it may be oiily O,4-O,6 pei'eent for great amounts o£waste roel< must be removed, judging from the eomparison of the roek

mined and the amount of ehrysotile fiber obtained from the roek, One thiiig whieh has 't-o be noted is that, aeeording to the condi'tions

o£ produet･ion hi'tl･-ierto l<nown in various loealities, 'the part wh'leh eoR'tain

the ehi'yso't･ile vein, exists in the small seale serpentinlte body, or in the

inargins of some widely distributed roek body. These fae'ts may be

applieable to the ease o£ ehyomite deposits in Ho}<kaido, Again, in thesertentinite area eoRtainings ehrysotile veins, there is often not･ed a

tendeney of various leucoeratic dil<es to iRtxude. From tke field evi-

denee, the oecuryenee of ehrysotile vein seems to be g'enet･ieally con-

nected with the leueoeratie dikes intruded int･o the se}'pent･ini{:e mass,

and would represen't the latGst phase of igneous aet･ivity in the area.

The existence o£ numerous veins of li,o.th't greenjsh pie.volit･e iseommenly obsez'ved in the ak=ea where chxysotile veins are well deve-loped. I n t･his ease, ehyysotile veins seareely eut one aiiothei', t･he pierolite

veins howevev, interseet no't･ only eh/aysot･ile veiiks bi.it also pierolite

z,oo ,i. Suzukl

veins themse}ves cyoss one anothe}a. These observati.oRs seem to su.ggest

that chrysotile may have erystaliizecl llt a lnst･aiit, prior to the deveiop-

meixt･ of pieroli'te wkieh oeeurred dvt]fing- a eompa±'at･ively long time. Without exeeption thin blaek layer, 2mm. or less wide, exists be-#weelt chyysot･ile fiber and yoek wall. Frhis layer is ehiefiy coix)posed

of bastite mingled with miiiute gz'ains of magnetite. Comparing 'the

ehemieal eoiinposition o£ t'kree matexials, viz,, ehrysoti}e fiber, hlack

zone and wall roek, in a certain single sample £rom the Nozawa minein the Yamabe dist･riet, it is eonspieuous `t･hat the eontent of irolt oxides

is quitte dlfferent in them, notLwithstanding the SiO,･ eonten'L in eaeh

inatevial is nearly constan't. [rhe eontent of IiXeO+Ii"e,.Q, in the wall

roel< is int･ermedia.te between 'those in the ehrysotile fibey and blaek

zone, as ls showil in the fol}owing 'table (StJzu- and INom"., i948).

T,usmr. IX. Serpeii£inite, b}aek zorse aBct chyysotile in a singie sample froin 'the Nozawa mine,Yamabe distyiet, Ishikari }?rovince,

Analyzed by [g]. iNoui-] (SuzvKi aixd INo{Js･), l948, p. 195),

uawan

A Bi'

]t

C D

sio,

Al,hO,l

FeL,03

FeO

MgeCao

ULO

iI･

i1ll

I

l

:l9,S7

l,OO

5.24

C',,80.

36.06

O,2S

l3.73

F 36,7T ?,

O,98

l1,41

5.S6

32,49

O.2'6

12,27

l

LIIll --..

I

4C}.9S

O,32

1,75

j,oe

4L),43

O.III

]3.41

I

[

iI'

lll

?,9.50

O.83

6,15

3.52

?,6,54

O. .l)2

l3.24

Total IOO.OO1'

11oo.oe IOO.OO

I/

loe,oo

Moieeu}ay pereent

Si02

Al,,Q,

Ii'e･HiO:l

I?eO

ft(gO

CaO

H,,O

]l

t

ll･

IiiII

2t7,3(l

O.40

l.35

2,'l9

37.11

O,21

:)l.3S

l.iIlII,Ii

l

27.07

O.4`.')

3.15

3.{}O

:]5.42)

O,k)O

30.l4

27.I S,

O, I k)

O,4:l

O,5fio

4.2.12

o.os

29.5S

l1･)7.#,r}

O,:l･1

11 ,60

i].03

37.96

O.]6

30.56

Tot,al Ii

'lOO,OO

tt

l!

]eo,ooi'

l loo,oe'j"

l IOO.OO

.rm

UIh'a-})asie Rocks and Assoeiated Oi'e l)eposits of Hokkaido, ,Jap.an 2C}l.

A.) Serpentinite. (See p. I2'O, [lrable Il', No. :;).

.B) BIaek zone. C･) Chrysoti}e.

D) Cht'ysotile vein with black zone.

It is probably reasonable to eonsidey tikae when the ehrysotile fiber

grevy f℃om se.vpent･inite during hydrothermal stage, iron oxides werese£ £ree and fomned 't･he "cl}in black- zone betvLTeen fiber and wall roek.

E. MERCUR¥ I)EPOSITS

As far as is known in ft'okkaido, only a few small areas in the

ultra-basie roeks have been miRed aitd prospected for ineyeviry deposit

of Iow grade, at the Teshio miine iik the OnnenaiC') dlstriet o.f Teshio

Provii}ce and a't Suigln-yaina(･L" iii the }ilorokanai district of lsk}il<ari

Il'roviBee (YtxJ"fA, 19,48 ; 1951 ; Suzui{i, 195ea).

The ayea of the Teshio mine is in steeply dipping Cretaeeous sand-

stone n.nd shale beds where they were ln'truded by serpentlnite, Theore, eonsisting mostly of einnabar and native mez`eury, oeegrs along the

sedimentanies whe±"e 'they eontaet with the serpentinit･e as eoating alon.crshear planes and along the fissures in these roel<s" (MuKxfrA, 1936),

At Suigin-yama, disseininated ore of low grade oceurs in the smali

sevpentinite mass Sn the metamorphies of Kamuikotan eemplex, butt}ie deposit has not ye't beelt zmdey production though some prospecting

}"ias been done with speelal refeyenee to 'the plaeer einnabar cteveloping

around the area (HAittNvA, 1943),

In both areas, where Che Teshio and Suigin-yama deposits exist,some differentiat･ed ieueeeraties oeeur in assoeiation with serpentinite

masses and where an immedia'te eontact of dike and mereury deposir

has often been ±'oimCl. This £aet suggests that these dil<es may bespeeially comiectecl with the oceurrenee of the deposits.

Besides the examples from t-he above eited areas, miikute grains

of einnaba}r are ofteh £ound in the }piaeey ehromite and iridosmh}edeposits in the Uasru distriee and othey localities, bu't it has noe yet;

beei.i eieayly aseertained from where they eame,

The largest deposit of meyeury in Japan i's at the Itomul<a`"> mineof Kitami Il rovillee in ffokkaiclo iixo}R which has been dez'ived usually

eighty pgycent or moyg, off tthe total piioduetion iii Japan (YA,TisfA, A951),

'S' liihe totEl produetion ot" t,l)e minerals from the m{ne for l9:S6--]945 amounts to about;

IOO metne tons,

(J) ,t5･M;Setig,. (2) 7S"-ptGlli, (3) ･T l･ -!h h,

202 ,]I. Suzuki}{{owever as that dGposlt is geltet･iea}jy eoltneeted wit･h the young Teytiary

voieanic roel<s and not "Tlt'h the ult･ra-basic roel<, a diseussion is n,ot

pert･ineil't in this paper,

F. NICKEL DEPOSI"I'S

Several sma}I niekei deposies have been knowtt in Kokl<aido. They

ean be divided iuto two types from t-he stanClpoint of their genesis.

The Kamikawa(i' deposit near the Kamuikot'an Valley in IshikariProvinee and the Shoei`2) deposit near Nakat･ombutsu`") in Kit･a.miPyovinee, are direetly relat･ed to serpentinites themselves in the Kamui-

1<ot･an eoiriplex (IsmK'A"rA, 1944a; l.944b; Ki){rosm'rA, 1943). The other

deposits in the Horoinan<") distriet of gidal<a Provinee, in the Oshira-

betsu`･S' distriet of [I]ol<aehiC6) Pyovince and in trhe Okushibetsu`･7' distrlet

of Teshio Provinee, are due 't･o the veinlet･s or fu)e grains of pentlandite

or polydymit･e in the disseminate'd ore or veins of pyrrhotite in thegabbroie masses intruded in 'the }{{idaka eoinplex (Ai<iNoi<!t, 1941; Ko-

]sttyAsifi, i941; Ktvro and KoBivytxsHi, Ii944; EiAsr{nforro, 1948b; 1951).

At the Kamikawa and Shoei mines, 'the o!'es weye residual ear'thyclayey matter derived from deeompositti'on of the underlying serpentinlte

mass, eontaining O.3-O,8 pereent niekel and 20-35 pereent iron. Thevesi' dual elay averages neayly several metex's in t･hiekness t･hough it

varies depending on the 'topography. Serpeniinite bloeks of varioussizes a}'e eemmonly found in the lower part of the residuai clay.

At the Kamil<awa mine, the underlying sevpen'tinite is partly pene-

h'ated by numeyous veinlets o£ ealeite and quartz, ki whieh a smallamount of garnieri'te and miilerite is found espeeially in the lower part

o£ the residrtal elay yesti'ng on the veined serpentinit･e, indiea'ting thatthe deposits were enrlehed by hydrothermal solution'`i.

The oceurrenee of a fine vein of miilerite is }<nown in a smal}isolated serpen'tinite mass neav ShikaRai"S' in Hidaka Pyovince but it

is very small in quantit･y and has iio eeonomic valLie,

G. COPPER DEPeSITS

Smal! and low-grade deposits o£ eupriferous sulpinide : re often foundin the serpent･inized ultra-basic masses t+hemselves in Hokkaido, but no';" Fr5m ]g4'l to l`}`!,ro,' I,he elay o£ the I<arnilgawa mhie was mlned by open-cut and the total

pvoduetion of erude ore witih an avera.cre grade O.6 pereent of niekel was about 4,OOO

.(l).Oil, (:3) [ll.{s"{-}, (3], iFjvaJlij, (tD iPj･C,?T¥s], <5) f,`i:l'･l'JiLli,lt,, (6) Fi-`)iS}, (7) ikL[Ir)3ij, (S) fiEtAg.

Ultt`a-basic }l･oel<s and Assoelated Ore Del)osits of Hokkaido, J'apan 203

lak'ge worl<able deposlt has been 1<nown. The deposits at the Chiroro(i)

and Niset"L') dist･riets in ]I{idaka Pyovinee, for exampl'e hold only a seiefi-

tif}c interest, oeeuryi.ng as nayrovLT vein or small mass whiek eonsist･s of

chaleopyxit･e, ehaleocite or bornit･e as an essential eorr}ponent <Suzum,

1950a).

It is also noteworthy thae in the superfieial residual elay or soll

yesting direetly on the seypentinite masses in the Shizuftai(:}) and Usappu('i)

distriet･s, there ai'e !oeally presene ore blocks and masses of native

eopper of irregular shape and slze, generally 3-10em, in maximumdiame'ter, many of whieh are slightly aeeompanied with cuprlte, mala-chite or azurite. They are mostly very pure and of high eopper content,

but usually exist in smal! quantiCy. From the geological and mineya-logieal viewpoint, it may reasonably be assumed that they origin,ated

seeondarily £]rom a euprlferous sulphide vein in the neighbouring ser-pentinite mass, but it is not elear how this was effected, because no

ciose relation between the native copper bloek anct its probabie souree

has been found 2ii any field.

In the outer zone o£ south-western Japan, there are numerous eupri-ferous pyrite deposks, so-eailed Besshi"5' t･ype deposits, which interealate

in the Sambagawa<") and Mikab'u(7) crystaMne schists in bedded form

and are eonsidered to be met･asomatie repiaeement produets by as-

cencling mineralizi･ng solution £rom ultya-basie intrusions eonneeted withthe great erustal movement. But no identieal ore deposit has beenknown in }[(okl<aido (K,Nrro, 1925a; 1925b; SvzvKi and Is.iiii{AwA, 1943).

In the zone o£ the Hidaka complex o£ eentral Hol<1<aido, some sinallpyrrhotite deposit･s are known to occur niostly in the metamorphic roel<

areas. Some cupriferous pyyi"u'e deposits ]represented by the large de-

posit o£ the Shimokawa(S' mine in Teshio Provinee, are lmown to occurin the s!a'te ayeas. These sulphide deposi'os a･ye of quite different natuye

in compayison with the Besshl type deposit. They aye eonsidered ge-netically to be eonnectad. with the diabasie and gabbroie roek intruded

in the Hidaka eompiex and noO xsTith the ultra-basic yoel< in it.

kl. TALC AND eTHER DEPOSITS

Besides the various ore depositts above described, theye eaii beeited here ot},fte]r mine]ra.1 de},)osit･s sueh as, tale, mazkganiferous iroii,

magnetite, ma.giiesi't･e, eobal't, eoirundum, ete., which may possibly oceur

a) 1,f･".ilSll, (,I],) -l-.ivi:Ji'-:, (:;i f,-giilj, (tt) >fii/i-:if-]:, (:･)) xiJJjt-, ({)) i-:::iLiem, (7) tsi]i}if':g'it, (g) riyii.

as gsefu} natkwal yesourees in viltva-basie roel{. Netwithst･anding the wide

disJcrubution of ultra-basie x'oeks in Ko}<l<aiclo, most of "ohe above eited

mateyials have not been known ba this island altd prospeet £or £utureimpoy'tait't diseeveries of them appear to be poe]r.

With respeet t･o tale, fov inst-anee, though t･a}eose serpeRtinite is

known to be plen'tiful in ffokkaido, lt is eommonly inferiox and use£ultale has not yet been found in it, In 'the sinali serpentkxite mass at

Kamie'tanbetsu(i) in Ishikari Provinee, a small manganiferous iyon deposit

with 5-10 pereent Mn akct 20-30 pereent Fe has been prospeeted but

the form aitd volume o£ it axe not yet asee]fta,ined aS pz'esent. F℃eshdunite itsel.f is often used as a refraeeory materia}. For this pyupose,

the pexidotites from Yuwanai-dake<2) and Horomall(") in Hidaka Provixxce

were pxospected and examined but is said eo be not suitab}e at present

to use on aeeount of the Iayge eoiitent of pyyoxenes in them.

, V. SVMMARY (1) This paper has ultdertake" to deseribe in outline the ultra-basic

roe}<s, and associated dike yocks, adjaeent eontaet ii}etamoxpkosed yocks,

as well as varlous ore deposits elosely related with the serpentinlte o£

Hokl<aido, Some shoz't aecount o£ the £undam.ei}tal geo}ogy of t･he eentyal

zone o±" Hokkaido where the ultra-basie roeks are predominantly dis-tiribut･ed, has also been ineluded. ']]he utt･ra-basie roeks whieh have only

a lim'iteCl developnient, beiiig restrieted inainly tto the tectoRie lines iii

or along the metamoJephi,c zone of the Kamuikotan and Hidaka eom-

plexes, in the £oym of lenses, belts oif mas$es ayxanging fyem the northto t･he south in lineay direetion,

(2) The styatigraphieal posit･ion and the age of the Kamuikotan

and Hidaka eomp.lexes are no't yet clearly aseertained, though £i'omthe geoiogical. aitd petrographieal pohits of vlew, t-he £ormexz eomplexmay be readily eoscyelated with the Fxancisean formation in Cali-fornia, and a payt of the latter eomplex may eontaik distine't-ive fea-

tuyes in eommo}i wlth the so-ealied Chiehibu system in Japan p.t'oper

and other parts, thougin these eomplexes are }oeally gyouped togetheywith the Jurassic sediment$,

(3) From Iate Mesozoic ei.me eefttral .Rokl<aido has been periodically

subjeeted to oyogenie i¥iovement･s producing pyessure fyom the east,

Igi)eovis ae'ti'vi'L.ies ae.eompanied tkose movement･s. Many geological £aets'(I') .l:.S.ll'Jl'J'"i, ('t'g) i",,iXH;';",''li'il`th'inga

℃Itya-basie Roel<s and Assecjated Ore Depes{t･s of }lold<aido, Japan 205

may reasonabiy be dedueed, for exampie that most of the intrusion of

the large ultra-basie masses in eentyal No}<l<aido belong to an early Ter-

tiary orogenic period.

(4) One of the distinetive featuyes is that the ultya-basic yoeks

yeiated to ehe Kamuikotan eomplex az'e extremely large in size andare now usually repyesented by serpentini'te, those of the Hidal<a eom-

piex, howevey, are generally small aitd eomparatively £resh, stM showingperidotltie nature. The t･otal area where sexpentinite is exposed in the

Kamui}<otan coiinplex far exeeeds alty other area whege such phenomena

are observed in Japan. (5) The ultra-basic yoeks in cent･yal Hol<kaido ean be roughly clas-

sified into two main petrographSe types ; peridotieie and serpentinitic

rocks. Eaeh of them ean be respeetively subdivided fyom the stand-point of constituenCs and strucXbures : peridotLitic rocks comprise dunite,

saxonlte, harzbuygite, wehTli'te, amphibole peridotite, pierite, plagioelase

bearizag dunlte etc; serpentinitic rocl<s iiaeiude massive serpentinite,

schistose serpentinite, talcose seypentinite and actino}ite-fels, etc.

(6) The serpentinite masses in the Kamuikotan complex aye oe-easionally traversed by numerous dike roeks of leueoeratie and me!ano-

cratie nature whieh may have been differentiated from the same magmarelated to the uitra-basic intrusives, The representattive kinds of those

dike roeks are albitite, quaytz albitite, quartz albitophyre, albite aplite,

anorthosite, trondhjemite, pegmatite, micyo-diorite, diorite-aplite, gabbiro-

aplite, hornblendite, titanaugite-fe}s, dlabase, etc, Some ieueoerates

may in origin have yelation to the genesis of some }<inds of ore deposks

for instance of chromite, mercury and asbestos. Rounded masses ofrodingitic roeks are often found in the serpentinite bodies.

(7) Various interest･ing eontaet rocks loeally deve}op betweeii the

noymal crystalline schists of the Kamuil<otan complex and the uitra-

basic inerusives. They are charaeterized by the p}'esenee of some o£the speeial silieates sueh as albite, glaueophane, crossite, riebecl<ite,

crosidolite, aegirine-augite, Iawsonite, garnet, piedmontite, sbilpnomelane,

pumpei!yite, rvteile, apatite, ete. Most of these speci'al mineyals are

consideyed to be a pyro-metasomatie product eaused by 'u'he action ofespeeially soda-rlch hydrothermal soiuttion clerived fyom the ultra-basie

intrusion. The eontaet rocks may be divided into maiiy elasses fromthe mineral association, chemiea} compositlon anc! miewo-structure,

<8) 'The ultra-basic roeks, espeeially sei"pentini'tes in L'Iokl<ajdo are

Qf speciai importanee beeause of their assoeiate61 ore deposits of various

kincls of vtse£ui knineyals sueh as ehyomite, iridosm;me, ehrysotile as-bestos, mereury, niekel, eopper, ete., thoggh $ome of them are notreeognized as eeonomleally at present, Most of these deposit･s oeeur

in ehe ultya-basie bodies themselves; ln vein or massive form, tkeyoyiginatLeCl un{iley ort･"noi:Ragmatie or hydrot･hex`mal eoit(lition, but some

o£ them, £or inst･aiRee iridosmine, gold aRd a part of tihe ehromits, areeoneentra,ted as placer deposits in the ailuvial plaiik a-rovaid the seypentin-

Short deseriptions outliRing tke general prope}'ties, the modes o£oceuyrenee and the genesis of eaeh deposit weye respectively presented

in ehis -paper.

(9) Most ef the known analyses of the ultra-basic rocl<s, associated

roeks and ores of Hokkaido were eited, but the details on eaeh roel<

and ore were not touehed upon heye, as some of them have already

been deseribed aiad ie is in.`,ended to present the others on some £uture . ' '

The writer desires to express his sineeye thanks £oy the assistanee

and in£ormation of various kinds given in prepayation o£ this paper atall tlmes by Prof.essors Z. HARAi.>A, T. Ismk",･"vA, Asslst. Professors M.

}{{uNttHitgi, S. II!Nsimforvo and many colleagues ln the Geo}ogica} and

Mineyalogiea! I)epartment o£ t}}e Hokkaido University.

LI[IiERATVRES

(0n the ultra-basie roeks and asso.niated ore deposii;s of Hokkaido.

" indieates articles written in Japanese,)

AK.xoK'A, J. ('l.939)i" Nickel deposit in the xxoroman distriet, Hidaka Provinee: Jour. Geol.

Soe. Japan, Vol. 46. pp. 32`.L3`24.

Aoy,N"kx, S. <l936)i' ftuthenosmiridium, a new mineral : ,}our, Jap. Ass. Pety. Min. & rceon.

Geol., Vol. 116. p. 7S.

BA}iB,x, T. (l952)be' UItra-basic rocks o£ tlie Chugoku district, south-westevR pavt o£ japan (I): Bull. Geol, Soe. ffokka.ido, No. 14, pp. 1-7.

}-Itu:nb',N, ". (1902)'" Glaucophane rocks from Obirashibe, [i]eshio Pyov,, }{ol<1<aido: Jouif.

Geol. Soc, Tokyo, Vol･ 9. pp. 9S=105, 147--l`IS.

Il,vvxpA, Z. (193tl) Ueber einen neuen Pektolithfund in Japan: Jour. Fae, Sei, Hokkaido

Imp, Univ,, Ser. IV, Vol, II, No, 4, pp. 3b5-359.

" (1939)"i' New data coneerns the a.[r,e e/f the seypentinite intrusion in Hokkaicio:

,Jouir. Geol. Soc. Japan, X,Jol. ili.). p. tt)75. ･'---""''-'-" (I9dC})""' 0n glaueophane ancl erossite, newly /founded from Iburi and I/lidRka

Provinees, l'.{okl<aido: Ibld. Vol, 4Jl, pp. t･ll9-'2L'3. ･ '"'' '' '''' and IsiEm.s,Liiii, fyI. (1940)":" On the chroineininevals of ,Japan I: Jour. jap･ Ass,

Petr. Min. & Eeon, Geol,, Vol, X'4. pp. I76-'183.

Ultva-bAsic }{oeks ai]e Ass'ociated Ore Depos:,ts ef Hekkaido, Japan ft{)7

liAiit"),x, Z. (19`34>"" On the ehvome-minerals o/f japan II : ibid , Vel. 29, pp. IL'--Sk'3.

- (r943)i' Cinnabar deposit at the Horokanai mine, Uryu-gun, Ishikari Proviiiee:

Ibid. VoL 29. pp. l59-l67J .H.･Nsiii"{oTo, S, (194S)":' Nickel bea.rinncr pyrrhotite and grapl)ite deposits of Osbirabetsu : Jour.

Mining Inst, }lokkaido, Vol, 5. pp, l20-l34.

(i949)" On the iiitrusive bodies of }IIorojiri-dake, Hidaka mount;ain range: Geo-

Io.rrical S:ience (Chikyu Ka:･;'algu>, No. I, pp. I7-2`2.

mamm (1951) On the niekel bearing pyrvhotite and g}rapliite deposits o£ Oshirabetsu, 7]okaebi Pr'ovince, }Iokkaido: Jour. Fac. Sei. Ho}<kaido Univ., Ser. IV, Vol. 7,

/ No. 7. pp. k'27-236.Hn}A, N. (1949,)X Oeeurrenee o/ff ehvyso-.ile asbestos in somemines. (AbstraeO : jour. Geol,

/ Soe, Tokyo, Vol, 55. p. I71.NuKiwA, A, (1949)X' On braehiopods from so-eal}ed schalstein formation of central mountaiR

. ran.cre oiE Hokka'ido: Jour. Geol. Soc. ,]apan, Vol. 55, pp. 1:"3-l24.

Uu,N,x.ii.･xsi, M. ('l944)"'sS Speeial amphibole sehists assoeiat;ed with serpentinlte in the Horori

kanai distriet, Ishikari Province : Ibid., Vol, 51, pp. 1].9-l,31.

L- --m (.I94S)'" Contaet metasomatism asso:iat.ed with the pyroxene peridotite of the

Horoman Region, in Hidaka metamorphie zone, Hokkaido : Jour. Fac. Sei. Hok-

kaido Univ. Ser. IV, Vol. S, No. 11, pp. 5'1-63. .

--- (1949)" On £rontal zene of migmatite of Hidakazone: Jour, Geol. Soe. Japan, Vol. 56, pp. I52-･l55'.

(i951a)ti Rocks of the Hidaka and Kamnikotan zones of Hokkaido: Geologicai

Seienee (Chikyu Kagaku>: No, g, pp. I09-llS.

`' ' ('1951b)":" Saruru mine, a eupriferous pyrvhotite deposit, Hidaka Prov.: Ibid,, No. 5, pp. 7-I4,

'rww"-"-' (1950>* On two types of ultva-basic i.crneous yoeks: Geol. Soe. Hokkaido, Bull.

15, pp, l-3,

'" T aRd S. IIAsi{["torro, (l951):t` Geolo,cr.y oE theHidaka zone: Monograph Ass. Geol,

Collaborat.ion, No, 6, pp, 1-3S.

IGi, Y. and [I]. BA}miN. (1950)t' Horoman pyyoxene peridotite mass (Abstraet): Jour, Geol.

Soc, Japau, Vol. b6, p, 263.

IsHiBAsm, M. ('1939)'i': On ro2ks /Erom the environs of Horaisan near Mitsttishi town, Hidaka

Provinee: Geol. Soe, Hokkaido, Bull, I.O. p. 7-34,

Is[iiK:"v,N, [l]eiji (IS9b)* Some speeial minerals from Hokkaido (Iridosmine, Platinurr], Cin-

nabar and Chromite>: Jour. Geol. Soc. [I]okyo, Vel, 3, pp. 245--`.'46.

wwmm-L (IS96)ec Geologieal and mineralog'ical survey of Hokkaido, 2nd Report. Hok- kaido-eho,

IsniK'AwA, Toshio (l940)"""' Chromite deposits o£ the [I]ari distriet, [I]ottori Pref. : Jour. Geol. Soe, Japan, Vol. {t7, pp. 2･･75--2S5.

rmrm'n (1944a)"" Kt}mikawa iiiekel mine, Ishikari Prov.: Sub-eomm, No. 5Sth, Jap. Soe･

Promotion o/ff Sti., Report 7L', pp, 1-25.

---"'-'--' (l.944b)'`' Shoe.i n{ekel mine, Kitami Prov.: Ibid, Report 73. pp. 1-20.

ji"mo, K. (1892) GeReral geological sketeh o/f Hokkaido with speeial re/eerenee to the petru-

graphy: }Iokkaido-cho,KAuio, [I]. ('i925a> The probiem o/f the euprit"erous pyvi'te [leposits : Eeon. Geol., Vol. L'O,

r""'""'-' (l92'5b) [I"h{}, euprl'/['e.vous p>,rite ove (/leposits o/Lrb the Shibuki and Seki IL(lines in

t'he I'rov, o/ti I]un,v.o, .}pan: Jour. 'Fae. Sei., Imp, Univ. IJokyo, Vol, i, parL X'.

pp. (;5--79.

r'mu""'''"' and H. KeB,tyAs]ix (l944) On the origin of the niekeliferous pyrrhotite cleposit

of Horoman mine in Hokkaido: Jap. Jour. Geol., & Geogv,, Vol. I2, pp. ,KtNoss;m'A, K. ('1947)"'" Niekel resourees (in Japan> : Sumrnarized Report. No. 1, Jap. Soc.

Promotion o£ Seienee, pp. I-57.Km'AiitmA, J. (1947)K Chemical studies on spinel group (I): Mineralogy and Geology <Ke-

butsu to Chishitsu), Vol. No. 6, pp. `.'58-261, and Jour. Geol. Soe. Japan, Vol. 53,

pp, 55--56.

-"'mm (l949)* Chemical studies on splnel group (II): Ibid. Vol,, 3, Ne. I, pp. ".7--30.

<l950)va Son)e problems on ehromite ores: Jour. Jap. Ass. Petr. Min. & Econ.

' GeoL, Vol, 34, No. 1, pp. I,3i'l. ･

KoBt"'issiii, ff, (1941)":' Niekel bearing pyrrhotite deposit o£ the Horornan mine, ri[idaka Pyov. :

Jouy. Geol. Soc. Tokyo, Vol. 47.

MATsu}ioTo, S. (1926)be' Compositien of placer platinum gyoup rnetal fvom Hokkaido : Jour.

Mining Inst, Japan, Vol. 42, p. 743.

Murata, S. (]926)i" Geology and mereury deposit o/ff the Teshio rnine: jour. Coal Mining

Ass, ffokl<aido, No. 26`"', p. ISe.

NAGi"vo, [[]･, O[pATsv}iit, K･ and R･ SAitro (i933)ee Geologi2al structuve of central Hokkaido

(I): Jour. Geol. Soe. Japan, Vol. 40, pp. 415-!67.

NAGA"ro, T. (19tt'4)" Geologieal structure of eentral Hokkaido (II): Ibid,, Vol. 41, pp, 339-

341.

Ng,;"!oTo, T., Stx}tp,oNsv(ll, M. and B. MizvKveJn (1942)'" Noborikawa Sheet (lllOO,OOO) aiid

Explanatory Text: Ind, Laboy. Hokkaido, Report No. 5, pp. I-31.Opstmsu･biit. K, G940)" Stratig.raphlcal relation between lowey ammonite bed and schalstein

torma'tion of eentral Hokkaido: Geol. Soc, Hokl<aido, Bull,, 11.

Oz:r.Ki, K. (]950)"' On the chromite deposits of Nukahira mine, Hokkaido : Bull, Geol. Surv.

Ja,pan, VoL l, No. 5, pp. 29-3:'. ' '-m (1951)ee Asbestosdeposit in the Nunobe-Yainabedistriet, Hokkaido: Bull.Geo}.

Surv. Japan, Voi. 2. Nos, 4-5, pp. I5'-IS.

S.･sui]o, M. <l.950){' Preliminary aspeet on the meeh:,in{sm o/E the origin of chrysotile asbestos

deposit: Geol. Soe. Hokkaido, Bull. 14, ppL S-l3".

S,sKuR,g, K. (1949)ee Iridosmine from Niseu, Hidaka ?trov. ; Mineralogy and Geolotsyy, No. I'2,

p. `-'40.

SJ"vA, [l]. (1950)" Western £aeies o£ Hidal<a migmatite zone at upper pavt o£ the Shibeehari-

R･iver (Abstraet): Jour. Geol. Soe. Japan, Vo}, 56, p. 263.

Suz(jici, J. (192･4)be' Glaueophane sehists in Japan: Jour. Geol. Tokyo, Vol., 31, I)p. 1-l7.

um '" (19b'O) Pet･rologiealstudy of the cvystalline sebist system of Shikoku : Jour. Fae.

Sci,, Hokkaido Imp. Univ., Ser. IV, Vol. s-', No. ], pp. 27-ltl.

umm verr (]931) Aesrivite-ausrite glaueophane quartz sehist from the Province of Teshio:

Proc. Imp. Acad,, Vol. 7, No, 7, pp. 2S3-X'S6.

- -'-'rm (191r,U･'a)'J" Crystalline sehists of Japan: Iwa.nami-koza.

L"-rc-mm <193Z'b)'"' I]oealitieso/ff glaueophanebearing roe}<s inHokkaido: Jour. Geol. Soc.

[l]okyo, Vol, 39, pp. II.3L'-l39.

h･-- --'- (193."c)';:" Some new data on glaucophane bearing roeks in Japan: Jour. Jap.

Ass. Petr, Min. & Econ, Geo}., Vol. 8, pp. ]S3--190.

('l933') Aegirine-au.rite bearing riebeelcite quaytz schlst from Kamuikot･an, etc, :

Proc. Imp. Aead., Vol. 9, pp･ 6'i7-62''O.

m""'---"" aiid S. Yamaguchi (1933)"' On thecontactmetamorphie efreee of basie intrusioRs

at the north-western mountain-Iand oif Asahigawa, ili[okkaido : Ibid., Vol. 40, No,

pp. 3S7-390.

Ultva-basie Rocks and Assoeiated Ore Deposits of Hokkaido, .]apaR 209

SvzEiK'i, J, ('l9;}4a)X Contaet metamorphie rocks related to the granitie roeks of Iiokkaido:

Jour. Geol. Soe, Tolcyo, Vo}. 41, pp. 394-･397.

(l9;ltlb)"r`' I}'etyography e/e sQ-ealled I<amuii<o`L'an metamorphics: Ibid,, Vol. 41,

No, 7, pp. 3-'92-394.

(1934c) On some soda-pyroxene and amphibo!e bearin.cr quartz sehists /ffrom Hol<-

'kaido: Jour. Fae. Sci. Hokkaido Imp. Univ., Ser. IV, Vol. No. 4, pp. 339-353.

(19,O,4d) Metamorphosed ealeareous coneretions in the horn£els at Tokaehi Prov. : Ibid., Vol. 2, No, 4, pp. 32,o,-O.2s.

<J9.",5a)i' On erondhjemite £rorn Horonari, Uryu distriet, Ishikairi Provlnee: Jouy･ jap, Ass. ?etr. Min, & Eeon. Geo}., Vol. 14, No. 6, pp. j55-l62.

(19?,5b)"' Piedmontite quartz sebist pebble from Utsunai, Kitami Prov. : Ibid.,

VoL l5, No. 2, pp, 2S5-1'S9. ･ (1935e)"'" On selective metamorphism: Seience (Kagaku-Iwanami>, Vol. 6,

Nos, 4-6.

(1936) Geology and mineral resourees of Hokkaido: jour. Bummei-K>Tokwai,

l)p, l.-7 .. and T. NE}fox'o (1935) Chemieal eomposition of granitie roeks of Japan : Jouv.

Fae. Sei. Hokkaido Imp. Univ,, Ser. IV, Vol. ?,, No. 1, pp. 1-4S.

(l9?,Sa) On the oeeurrenee of ae.cririne-augite in natrolite veins in dolerite £rom Nemuro : Jour. Fae, Sei. Hokkaido Univ,, Ser, (IV), Vol. 4, Nos, l-2, pp. IS?,-]91.

(193Sb)"' On peeuliarity of the ancient roeks of Japan: Jour. Jap, Ass. ?etr.

Min, & Eeon. Geol., Vol. 19, No. 2, pp, 123-l36.

(1938e)" On Iawsonite and pumpellyite from the Kamuikotan Valley, IshikRri

Prov,: Ibid,, Vol, 20, No. 6, pp. IS9-l96.

(l9?,9･a) A note on soda-amphiboles and pyroxene in erystalline sehist from Hok-

kaido: Jour, Fae, Sei. ffokkaido Imp. Univ,, Ser. IV, Vol. 4, Nos, 3-4, pp. 507-519.

- (1939b) On the a.cre of the Sambagawa system: Proe. frnp. Acad., Vol,15, No.

I, pp. 56-59. (1939e)"`" Petrol6gieal sLLudy of the Mikabu and Kamuikotan systems: Comm.

No. 6, Jap. Soe. Promotion of Seienee, Bull. 1, pp. 7-?,5.

and M. SAMBoNsu{n (1939)"X' Chromite deposits in Hokl<aido: Jour. Geol. Soc.

Japan, Vol. 46, pp. 3'L'4-3,26.

(1940)" Leucoeyatie roeks assoeiated with serpeittinite in Hokkaido; Jour. Jap,

Ass. Petr. Min, & Eeon. Geol,, Vol. 2:]b INIos, 2'--3, pp･ 65--Se, 124-142.

(1941)be' On asbestos from E{okkaido : Ibid, Vol. L'O, Nos. 5--6, pp. 207-221, 26i)--2Sl,

(1942a)"{' Chromite ores £rom Hokkaido: Ibid. Voi, 2"7, Nos, :;--4, pp･ 1115-lk'Z

183-194,

(194`2b)"' Plaeer ehrorni'te deposits o£ Holgkaido and Saghalin; Ibid,, Vol. L7,

No. 5, pp. 250£15J (l94?,a)'-: A eontvibution to the knowledge o/E the orlgin of ehvomite ore deposit :

Ibid,, Vol. 29, No. ?- pp, 56--62.

(1943b)"`' Chroipite deposits of Japan (Ms) : Sub-eomm, No. 2. Jap. Soe, Promotion

of Scienee., Summarized Repovt 2'. pp. I-l22, and [V. Isiiiff."yA ('l943)i:' Cupri/eerous pyrlte deposit of eastern Shikoku (Ms) : Cornm.

No. la', Jap. Soc, Promot;ion of Seienee, Summarized Report ?,, pp. 1-14L'.

(19E't4)'i`' An outline of the g'eolo.rry o/ff ffol<l<aido: Jour. Geol. Soe. ,Japan, VoL

51, pp. I5-24.

<1946a)"" On the oecurrenee o/ff ehrysotile asbestos in serpentinite : Sub-eomm,

2iO ' ,}. Suzuki No. 5S, Jap. Soe. Pro'motion o/f Seienee, Report SO, pp. 1-IO.

Suzuki, t}. and [[]. rsii{KAxvA ('l946)" Difi4erenee o.f ehvomi'te deposits o.f I{Iokkaido and Cbyu-

goku: Sub-eomm. No. Ibid. Repokrt; No, Sl, pp. ].-9.

- and 1]. INovi･: (194S)"`' A eontribution to the knovLTIeds,e of the origin of ehrysotile

vein (Abstract): Jour. Geol, Soe. 3apan, Vol. 54, pp. I94-195.

(1949)"" Ultra-basie roeks and assoeiated oxe deposits. (Pyeeidential Address, 55th

General Meetifig): Joue. Geol. Soe, Japan, Vol. 55, pp. Ill-"3.

ww-"rmrm (l950a)" Types of ore deposits associated with ultra-basie yoeks in Japan : KaRaku

(Scienee), Vol. 20, No. 1, pp. 16-24.

L Lm (1950b>":' Plaeerdeposits of platinmui group rr}etals in Hok!<aido: Geol, Soe. Hok-

kaido, Bull. Ne, I4, pp. I-41.

rrT-"m'r' (1951,)i"' Somepillow lavasin Ilokkaido(Abstraet) : Jour, Geol. Soe- Japan, Vol.

57, p. 319.

TAit'.･vitNs]ii, R. (l94]) Plaeer platinum group metals from Hokkaido: Jour. Minlng Inst,

Japan, Vol. 57, p. 590.

rmT' ' and [l]. TANAKA (1947) On theiridosmine pvodueed iii Hokkaido:Ibid., Voi. 63,

･ pp. 59-70.CPAK'AifAsHr, [I]. (1!92L') Chromite mines and their deposits of Hokkaide: Jour. Coal Mining

Ass. Hokkaido, No, 2･･5.

rr'AK'Eu(･m, X. and M. SA}moNsucg ({93S)':' Uyakawfl Sheet (I!oVO.OOC)) and Explanatory [I]ext: ･

Rep. Ind, Labr, Hokkaido, No. 1. pp. iS.:].

Y,xm･i, II. and [I]. Svc-tiy,NMA Q941)'- Diseovery oi] (]th"eo?)orella, se]n･ilclath7'(eta HAyAsAi<',x in

Hokkaido: Jeur. Geol. Soc. Japan, Vol, 48, p, 41.

Y,N,imA, S. (l951)"" Mercury deposits o£ Hok'Kaido: Geol. Soc, Iffokkaido, Bull. No. 17. pp.

1-78.YosmMvnA, T. (1936)"" Garnet fvom Mitsuishi, Hidaka Prov,: Jour. ?ei;v, "(in. & Econ.

Geol. Ass,, Vol.'l¢ pp. 257£65.WA･pAsir. S. ('1927)";:' Platinum group inetal o/6 Hokkaido : Jour. Ce'al Mining Ass, EIokkaido,

. No. l51, pp. I-2. . .WA'rAsi･i, S, ('Z9;l3>":' Platinum group metal : Geol, and Mi/n, Seetio]y !wanamikoza, pp. ]-?,8.

November 2e, l951

Department; of Geology and Mineralo.cry,

Faeulty o/e Scienee,, Hol<kaido University, Sapporo