Late Paleozoic Subduction - U

Lat
ePal
eoz
oi
c Subduct
i
on
a
"
ndAccret
i
on i
n Sout
hern
Chi
l
e
UN
by Fr
a
nc
i
s
c
o He
m}
The Coas
t Ranges of souther
n Chi
l
e are underl
ai
n f
or the
most part by a vari
abl
y met
amorphosed s
ubduct
i
on compl
ex
of l
ate Pal
eozoi
c age. I
n a contri
but
i
on to I
GCP 279,
"
Terranes i
n Lati
n Ameri
ca,
" the aut
hor revi
ews the
deposi
t
i
onal and met
amor
phi
c devel
opment of t
hi
s huge
accret
i
onar
y uni
t devel
oped i
n the Gondwana cont
i
nental
mar
gi
n. South t
o north tr
ansport of the accr
eted mat
eri
al
par
al
l
el t
o the conti
nental mar
gi
n may pr
ove to have been
and are s
pat
i
al
l
y rel
at
ed t
o gol
d-beari
ng bodi
es wi
thi
n the
a
n i
mp
or
t
an
t t
ect
on
i
c pr
o
ces
s i
n t
h
e r
e
gi
on
.
(
Ed
.
)
and nei
ghbouri
ng i
sl
ands.
s
chi
s
t
s (
Zuec
o
ne,
per
s
on
a
l
commun
i
c
at
i
on,
19
8
8)
.
Pr
i
mar
y
sedi
mentar
y st
ructures ar
e wel
l pr
es
erved i
n the mor
e
east
erl
y port
i
ons of the compl
ex, i
n par
ti
cul
ar i
n the
Nahuel
but
,
q Mount
ai
ns and the Chonos Ar
chi
pel
ago.
The
turbi
di
te sequences i
n the l
att
er di
spl
ay promi
nent graded
beddi
ng,
s
edi
ment
ar
y l
ami
nati
on,
and occasi
onal gr
ooved
b
as
e st
r
u
ct
ur
e
s (
Fi
g.
2)
.
Th
i
ck s
an
dy uni
t
s e
xi
s
t at
Pat
r
an
ca
The Chonos Archi
pel
ago i
s al
so character
i
zed by the
Introducti
on
pr
es
e
nce of wi
d
es
pr
e
ad m6l
a
ng
es
.
Tur
bi
d
i
t
e se
q
uen
ce
s ar
e
di
s
r
u
pt
e
d t
e
ct
oni
ca
l
l
y (
Fi
g.
3
)
an
d co
nt
ai
n a f
e
w e
xot
i
c
A ma
i
n po
r
t
i
on of t
h
e Co
as
t
Ran
g
es of Ch
i
l
e,
s
o
ut
h of
W S,
cl
ast
s of meta-i
gneous or
i
gi
n up to sever
al
metres l
ong
i
s under
l
ai
n by i
gneous and metamor
phi
c compl
exes.
The
met
amor
phi
c r
ocks have been consi
dered to be Pr
ecambri
an
eastern l
ow-gr
ade ar
eas
. However,
because s
chi
sts f
ormed
(
Rui
z
,
1
96
5
)
an
d we
r
e r
ep
r
es
ent
ed as s
u
ch i
n t
h
e 1
:
5
,
0
00
,
00
0
ge
ol
ogi
c
a
l
map of So
ut
h Amer
i
ca (
Har
r
i
n
gt
o
n,
1
9
62
)
.
How-
ev
er
,
du
r
i
n
g t
h
e l
a
t
e 1
9
60
s a
nd e
ar
l
y 1
970
s
,
t
h
es
e comp
l
ex
es
were s
hown t
o have conspi
cuous met
amor
phi
c and str
uct
ur
al
z
oni
n
g (
Gon
z
hl
e
z-
Bon
or
i
no
,
1
971
;
Gon
zA
l
ez
-
Bon
or
mo a
nd
Agui
r
r
e,
19
7
0)
,
as i
n t
he p
ai
r
ed me
t
amor
ph
i
c be
l
t
s of Mi
ya
-
shi
ro (1961)
.
At the s
ame ti
me, r
adi
ometr
i
c dati
ng of the
compl
exes f
ai
l
ed to yi
el
d ages ol
der than Carboni
f
er
ous
(
Muni
za
ga,
19
67
;
Mu
n
i
za
g
a e
t al
.
,
1
973
;
He
r
v
& e
t a
l
.
,
1
97
4
)
.
Uven though t
he meani
ng i
n t
erms of the geol
ogi
cal event
s
they repr
esented was not abs
ol
utel
y cl
ear,
both Rb-Sr whole
rock i
sochr
ons and K-Ar dati
ng on amphi
bol
es were i
nt
er
-
preted as ages of metamor
phi
sm,
and l
i
tt
l
e coul
d then be
sai
d about the age of the pr
otol
i
th.
The ass
oci
ated grani
t
oi
ds wer
e i
ndi
cated as Cret
aceous i
n
t
he 1
:
1
,
0
00
,
0
00 geo
l
o
gi
c
al
ma
p of Chi
l
e (
An
on,
19
6
0)
,
b
ut
r
ad
i
omet
r
i
c dat
i
n
g (
Mu
}
oz-
Cr
i
s
t
i
,
1
96
4;
Her
v6 et
al
.
,
1
976
a
)
provi
ded convi
nci
ng evi
dence that t
he gr
ani
t
oi
ds were al
so
empl
aced duri
ng the Carboni
f
er
ous
. These fi
ndi
ngs l
ed to
the convi
cti
on that very i
mpor
tant t
ectoni
c and
pet
rogeneti
c processes had t
aken pl
ace dur
i
ng the l
ate
Pal
eozoi
e i
n thi
s conti
nental mar
gi
n of Gondwana.
Thi
s paper pr
esent
s a synthesi
s of l
i
thol
ogi
c,
str
uctur
al
,
mi
neral
ogi
c and chronol
ogi
cal dat
a on t
he metamorphi
c
compl
exes and i
nt
er
prets thei
r mode of ori
gi
n and empl
ace-
ment wi
t
hi
n the concept
ual fr
amewor
k of pl
ate tectoni
cs.
For descri
pti
ve purposes the ar
ea wi
l
l
be di
vi
ded f
rom nor
th
t
o south i
nto the Pi
chi
l
emu ar
ea, t
he Nahuel
buta mountai
ns,
t
h
e Temu
co
-Ch
i
l
o
6 ar
ea
,
t
he Ch
on
os Ar
ch
i
pe
l
a
go,
t
he Ma
dr
e
d
e Di
o
s Ar
ch
i
pe
l
a
go an
d Cor
di
l
l
er
a Dar
wi
n (
Fi
g.
1
)
.
Li
thol
ogy
(
Gar
r
i
do
,
1
9
87
)
.
A
l
}l
an
ges ar
e we
l
l
r
ec
o
gni
z
e
d on
l
y i
n t
he
wi
t
h m6
l
a
nge
s as a pr
ot
ol
i
t
h ar
e i
n
di
s
t
i
n
gui
s
h
ab
l
e f
r
om
ot
h
er s
chi
s
t
s
,
m6
l
an
ges
ma
y h
ave be
en or
i
gi
nal
l
y mor
e
abundant than pr
esent
l
y recogni
zed.
Met
a-basalt
s are wi
despread,
most
l
y as gr
eenschi
st
,but al
so
gr
e
en
s
t
on
es wi
t
h pi
l
l
ow s
t
r
u
ct
u
r
e
s ar
e pr
e
s
en
t (
fi
gs
.
I
an
d
4
)
.
Ge
och
emi
c
al
s
t
u
di
e
s of t
he
s
e met
a-
b
as
i
t
e
s Oi
er
v
6,
19
7
7;
Her
v} et
a
l
.
,
19
7
6b;
God
oy
,
1
9
79
,
1
9
80
,
1
9
86
)
i
n
di
c
at
e t
h
at
t
hey have geochemi
cal char
act
eri
sti
cs si
mi
l
ar to those of
m odern ocean floor basal
ts.
Met
a-chert
s are al
so common,
many bei
ng i
r
on r
i
ch,
wi
t
h Fe
gr
ad
e
s up t
o 40% at
t
he Ma
hu
i
l
q
ue de
p
os
i
t
s (
3
80
S)
,
c
o
n-
t
ai
ni
ng sever
al mi
l
l
i
on t
ons of ore. A pos
si
bl
e envi
ronment
f
or the deposi
ti
on of met
a-
cher
t i
s i
ndi
cated by the Madre
de Di
os out
cr
ops
, wher
e met
al
l
i
f
er
ous red cherts di
rect
l
y
overl
i
e pi
l
l
ow basal
t
s and are overl
ai
n i
n turn by radi
ol
ar
i
an
r
i
ch g
r
e
en ch
er
t
s (
For
s
yt
h
e an
d Mpo
d
oz
i
s
,
1
9
79
)
.
Geo
che
m-
i
str
y of t
he l
att
er and of t
hos
e ri
bbon chert
s i
nt
erbedded
wi
th the turbi
di
t
e s
equences at t
he Chonos Ar
chi
pel
ago
(
Fi
g
.
5
)
a
r
e n
ot i
n
comp
at
i
bl
e wi
t
h d
ep
os
i
t
i
on i
n a r
e
gi
on
af
fected by ocean ri
dge hydr
ot
hermal proces
ses.
Li
mest
one and i
t
s met
amor
phi
c equi
val
ents ar
e ver
y r
ar
e i
n
the compl
ex, wi
th the mai
n outcr
ops at t
he northwest
ern
shor
e of Lago General Car
rer
a,
and at the Madre de Di
os
Ar
c
hi
p
el
a
go
.
Fo
r
s
yt
h
e an
d Mp
od
ozi
s (
1
98
3
)
c
onc
l
u
de
d t
h
at
the l
att
er wer
e deposi
t
ed i
n an oceani
c i
sl
and f
r
ee fr
om
detr
i
tal conti
nental i
nf
l
uence.
Pr
obabl
y the s
ame envi
r
on-
ment pr
oduced the Lago Gener
al Carrera marbl
es, presentl
y
the si
t
e of i
mportant Ph, Zn, Cu and Ag mi
ner
al
i
zat
i
on
r
el
at
ed to the i
nt
rus
i
on of Lat
e Cretaceous pl
ut
ons i
nto the
met
amor
phi
c compl
ex.
Ser
pent
i
ni
te bodi
es metres t
o sever
al ki
l
omet
res i
n l
ength
The met
amor
phi
c rocks of southern Chi
l
e ar
e domi
nant
l
y
are common i
n part
s of t
he compl
ex,
i
n parti
cul
ar bet
ween
turbi
di
te sequences and t
hei
r metamor
phi
c equi
val
ents
38 an
d W S.
The
y s
eem t
o h
av
e be
en t
ect
on
i
c
al
l
y emp
l
ac
ed
s
chi
st
) w hich constitute vast areas in the
(
phyl
l
i
t
eand mica i
nto the surroundi
ng schi
sts duri
ng an ear
l
y st
age of meta-
west
ernmost out
cr
ops
, and have a character
i
s
ti
c spott
ed
mor
phi
sm.
They contai
n no rel
i
c si
l
i
cate mi
ner
al
s
, but i
n
appearance, bl
ack al
bi
tepor
phyr
obl
as
tsbei
ng ver
y abundant
s
ome of t
hem podi
f
orm l
ens
es and vei
nl
ets of chromi
te or
i
n them . Som e m ica schists are ri
ch i
n gr
aphi
ti
c mat
eri
al
,
chromi
t
e + pyr
roti
te + pent
l
andi
t
e are f
ound. The ul
tr
a-
EPI
SODES,
Vol
.
11
,
No.
3
,
Se
pt
embe
r 1
98
8
183
maf
i
c i
gneous r
ock parentage i
s al
so cl
e
ar
l
y i
n
di
c
at
ed by
ba
s
t
i
t
e s
t
r
u
ct
ur
e of t
h
e an
t
i
g
or
i
t
e
.
Som e have brecci
a
str
uctures that can be i
nt
er
preted as m6
l
an
ge
s (
Gan
a an
d
Her
v6
,
1
98
3
)
.
Li
mi
t
ed ma
j
or el
emen
t ch
emi
st
r
y d
at
a (
Oj
e
da,
1
97
6
)
i
ndi
cat
e Al cont
ami
nati
on by the host r
ocks
. Nb-Sm s
tudi
es
on the Qui
tr
at
ue s
er
penti
ni
te i
ndi
cate val
ues characteri
s
ti
c
of de
p
l
et
ed h
ar
z
bur
g
i
t
i
c r
ock
s
,
whi
ch ar
e comp
ar
ab
l
e t
o
f
l
o
or
,
at s
pr
e
adi
n
g r
i
d
ges (
He
r
v6 et al
.
,
1
9
76
b,
Godo
y,
19
86
)
,
f
rom i
ntr
aoceani
c vol
cani
c ar
e mat
eri
al
,
or fr
om i
sol
ated
o
ce
an
i
c i
s
l
and
s or gu
yot
s (
For
s
yt
h
e an
d Mpod
ozi
s
,
1
9
79
)
.
Met
al
l
i
fer
ous s
edi
ment
s as wel
l as mas
si
ve s
ul
phi
des
deposi
ted over basal
t
i
c mater
i
al i
s a char
act
eri
sti
c of
near-
ri
dge envi
ronments
. The extremel
y l
ong extensi
on of
t
he c
ompl
e
x a
l
on
g t
h
e pr
es
e
nt c
oa
s
t of Sou
t
h Ame
r
i
c
a (
250
0
km,
s
ee Fi
g
.
I
of
Ramos
,
t
h
i
s i
s
s
u
e
)
a
l
l
ows e
n
ough s
pac
e f
or
al
l of these di
ff
er
ent t
ect
oni
c sett
i
ngs.
Met
amor
phi
s
m
画圈围圈圈圈圈固
mant
l
e beneath acti
ve mi
d-ocean r
i
dges.
Sul
phi
de pods and
l
ayer
s,
usual
l
y host
ed by greenschi
st
, consti
tut
e vol
umet
-
ri
cal
l
y mi
nor but wel
l
-di
str
i
buted component of the meta-
mor
phi
c compl
ex. They are composed of pyr
i
te-pyrr
ho-
The met
a-basi
t
es may have been deri
ved f
rom the ocean
t
i
t
e
-
s
ph
a
l
e
r
i
t
e
-
ch
al
c
op
yr
i
t
e a
ggr
eg
at
e
s (
Col
l
a
o e
t al
.
,
1
9
86)
Met
amor
phi
c gr
ade v
ar
i
es f
r
om ea
s
t t
o we
s
t acr
os
s t
h
e be
l
t
wi
th mi
nor mackonawi
te,
gal
ena and borni
te.
but has some remarkabl
v const
ant f
eatur
es al
ona i
t. A
井1苦
er
口圃珊困口口
TURBI
DI
TE SEQUENCE
SCHI
STS, METABASI
TES,
ME
TACHERTS, SERPENMNI
TES
标
'O'
Higgins
PILLOW LAVAS
PALEOZOI
C GRANI
TOI
DS
Rb-Sr AGE
a
飞r
/ 66Sr I
NI
TI
AL RATI
O
圈圈圈圈圈
、 、 、 卜
火
尸
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淤
、 J
A
a
o
h
u
n
.
t
o
[
V
i
n
s
t
a
{
AMPHIBOLITE
FACI
ES ROCKS
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彬秘 狐一
+
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1
留
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91
1
V
}
,
RAGO J
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1
.厂
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弓1・1
〕 34
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1
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ALPARAI
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C
O
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6
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-
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54
、
74
70
祀
一
一
74
、
N O 廿1
欢
兮
-:
l
i
a
l
o
n
d
e
Ch
刀侧划
甘
J
“ ・
42
N 划 j
I
; 矛r( l
R
画画围圈圈 圈圈圈回画圈回
32
_
一
哪
羚布
Figure 1: The metamorphic and plutonic complexes
of the Andes south of 340S, showing Rb-Sr whole
Car
boni
ferous gr
ani
toi
d bel
t i
s the eas
ter
n l
i
mi
t nor
th of
rock isochron dates.
t
o
war
d
s i
t
,
mo
vi
n
g f
r
om l
ow-
g
r
a
de bi
ot
i
t
e
-
be
ar
i
n
g gr
e
en
-
The l
i
t
hol
ogy of t
he metamor
phi
c compl
ex i
ndi
cates that i
ts
pr
o
t
o
l
i
t
h wa
s gen
er
at
e
d i
n an o
cea
ni
c en
vi
r
onme
nt
.
Th
e
ma
i
nl
y t
u
r
bi
di
t
i
c comp
os
i
t
i
o
n of t
h
e e
a
s
t
er
nmos
t
out
cr
o
p
areas
, suggest
s that t
hei
r sour
ce was a conti
nent
al margi
n
t
hat provi
ded abundant detri
tal mat
er
i
al t
o the conti
nent
al
s
he
l
f
,
a
n
d pe
r
ha
ps b
ey
on
d.
A de
e
p-
s
e
a f
an en
v
i
r
o
nme
nt
was
e
nv
i
s
age
d b
y God
oy an
d ot
her
s (
19
8
4)
f
or t
he t
u
r
bi
di
t
i
c
s
eq
uen
ce of t
he Chon
os Ar
chi
pe
l
ag
o,
i
n vi
e
w of i
t
s s
edi
-
mentar
y f
aci
es and the i
nter
bedded pel
agi
c r
adi
ol
ari
an
c
h
er
t
s
,
wh
i
c
h wou
l
d ha
ve b
ee
n ge
ne
r
at
e
d i
n f
an l
ob
es dur
i
n
g
i
nacti
ve per
i
ods
.
184 EPI
SODES, Vol
.
11, No. 3,
September 1988
38
*
S,
wi
t
h a s
t
r
on
g met
amor
phi
c gr
a
di
e
nt i
ncr
ea
s
i
ng
schi
st f
aci
es i
n t
he west, through conti
nuous andal
usi
te and
di
sconti
nuous s
taurol
i
te zones,
t
o hi
gh-
grade si
l
l
i
mani
te-
co
r
di
er
i
t
e
-
ga
r
ne
t gne
i
s
s
es
.
Th
es
e met
amor
phi
c zo
nes ar
e
devel
oped i
n t
he t
ur
bi
di
te sequence rocks,
and are devoi
d of
meta-basi
t
es acros
s t
he 20 km outcrop wi
dth.
So
ut
h of 3
8
0
S,
t
he l
a
t
e Pal
e
oz
oi
c gr
an
i
t
oi
ds ar
e a
bs
ent
,
e
xce
pt
f
o
r a s
mal
l ma
s
s
i
f i
n t
he Pa
ng
ui
p
ul
l
i
-
Ri
?
i
i
h
ue ar
e
a
(
e
as
t of Val
di
vi
a)
,
an
d t
he me
t
amo
r
ph
i
c compl
e
x i
s i
n
t
r
u
de
d
by t
he Nor
t
h Pat
ag
oni
an b
at
h
ol
i
t
h of Ju
r
a
s
s
i
c t
o Cen
ozo
i
c
ag
e,
wi
t
h o
nl
y ver
y n
ar
r
ow (
50
0 m or l
e
s
s
)
h
or
n
f
el
s
i
c c
on-
tnet m irpol
eq. Riotite and occasional andalusite are char-
鬓摹
Figure 2: Very low-grade meta-turbidites showing
well-preserved bedding, Chonos Archipelago.
Figure 4: Greenstone with well-preserved pillow
act
eri
sti
c, and st
aur
ol
i
te and s
i
l
l
i
mani
t
e occur s
por
adi
cal
l
y.
At Cordi
l
l
era Dar
wi
n, a st
auroli
te-kyani
te zone i
s devel
oped
near the contact wi
th a Jurassi
c pl
uton.
of Pichilemu。
A regi
onal
metamor
phi
c gr
adi
ent i
ncr
easi
ng westwar
ds i
s
i
l
e
mu.
Laws
o
ni
t
e h
a
s on
l
y be
en r
ec
or
de
d f
r
om Ch
i
l
o
6 I
s
l
a
nd (
S
al
i
ot
,
19
68
)
,
whe
r
e i
t i
s ac
compa
ni
e
d n
ot b
y gl
au
co
pha
ne structure and geochemically similar to present da
y
ocean floor basalts. Punta de Lobos, 5 km south Si
mi
l
ar mi
neral
assembl
ages occur i
n the northern sect
i
on
where sporadi
c abundant Na-amphi
bol
e occurs
, as i
n Pi
ch- wel
l
d
eve
l
o
ped away f
r
om t
h
e i
n
f
l
u
enc
e of t
h
e gr
an
i
t
oi
d
s
,
both in the northern and southern secti
ons. At the Chonos
but by chl
ori
te and al
bi
te. South of t
he Tai
t
ao Peni
nsul
a,
Na-amphi
bol
e has been recor
ded i
n otherwi
se t
ypi
cal Archi
pel
ago t
here i
s a conti
nuous i
ncrease i
n the cr
ystal
-
l
i
ni
t
y of i
l
l
i
t
e f
r
om CR (
r
el
at
i
v
e cr
ys
t
al
l
i
ni
t
y)
2
27
,
i
ndi
ca
-
t
i
n
g ve
r
y l
ow-
gr
ade me
t
amor
ph
i
c c
on
di
t
i
on
s (
Gar
r
i
do,
1
98
7
)
,
t
o CR 11
8
,
i
mpl
yi
n
g l
ow-
gr
ad
e met
amor
phi
s
m.
Ded
uce
d
t
empe
r
at
ur
es va
r
y f
r
om a mi
ni
umum of 20
0
'C t
o a maxi
-
mum of
400
0
C.
The we
s
t
er
nmo
s
t ar
e
a
s a
r
e t
y
pi
c
al
gr
e
en
-
gr
e
en
s
ch
i
s
t
f
ac
i
es as
s
emb
l
a
ge
s (
Fo
r
s
yt
h
e an
d Mpo
doz
i
s
,
1
97
9
)
.
Hi
gh
er gr
a
de r
o
ck
s c
ont
ai
n
i
n
g omph
ac
i
t
e a
r
e f
ou
n
d excl
usi
vel
y as l
oos
e boul
ders i
n spati
al ass
oci
at
i
on wi
th a s
er
pe
nt
i
n
i
t
e bo
d
y a
t Los Pabi
l
os (
400
S,
Kat
o,
19
8
5)
,
pr
o
ba
bl
y havi
ng been tect
oni
cal
l
y br
ought to hi
gher l
evel
s al
ong wi
th the ul
tr
amafi
c body.
, the r
ocks of t
he west
ern par
ts of t
he metamor
phi
c
一 meta-basi
tes: al
bi
te-epi
dote-chl
or
i
t
e-acti
nol
i
te Thus
compl
ex cont
ai
n greenschi
st f
aci
es ass
embl
ages wi
th some sphene(
士Na amphi
bol
es
),
i
nd
i
ca
t
i
o
ns o
f h
i
gh
er pr
es
s
u
r
e mi
ne
r
a
l
s
.
Kat
o M i
d)
ha
s
一 mi
ca schi
st
s:
quartz-al
bi
t
e-chl
or
i
te-muscovi
te
pr
e
s
en
t
e
d ev
i
de
n
ce t
hat
a f
or
me
r hi
gh gr
e
en
s
c
hi
s
t
-
l
ower tourmal
i
ne,
amphi
boli
te ass
embl
age was present i
n thes
e rocks near 一 met
a-cherts
:
quart
z
-s
ti
l
pnom el
ane-magnet
i
te
Val
di
vi
a. The sphal
er
i
te
-ch
al
copyr
i
te geot
hermometer (
1 Na-
amphi
bo
l
e)
.
s
uggest
s pr
ess
ures of 6.5 1 2.
5 Kb f
or the met
amor
phi
sm of schi
st faci
es r
ocks wi
th the f
ol
l
owi
ng mi
neral ass
oci
ati
ons:
mas
s
i
v
e s
ul
ph
i
d
es i
n gr
ee
ns
c
hi
s
t
s n
ear Co
nce
pc
i
6n (
Col
l
a
o et
al
.
, 1986)
.
翼
翼
Structure The st
ruc
tur
e of t
he compl
ex i
s wel
l di
s
pl
ayed i
n the
Nahuel
but
a Mountai
ns and the Ur
i
onos 八r
cni
pei
ago k
ri
g.
u
).
I
n the f
ormer area, t
he eastern part of the secti
on has t
he 一F
ia
ure 5:
Ra
di
ola
ri
a-
bea
ri
nq ri
bb
on ch
er
ts at
一
Ch,
37araup。 工sland . Chonos ArchiDelaao . have aeo-
Figure 3: M41ange at Teresa Island in the Chonos
一
Archipelaqc.
} siliceous sediments near modern mid-ocean ridges.
chemical characteristics similar to metalliferous
EPI
SODES, Vol
. 11,
No. 3, Sept
ember 1988
185
ge
ne
r
al
s
h
a
pe of a s
y
nf
o
r
m wi
t
h gr
a
ni
t
oi
d
s l
o
cat
ed i
n i
t
s
ce
nt
r
e
.
Pr
i
mar
y s
t
r
uc
t
ur
es ar
e pr
e
s
er
v
e
d i
n t
h
e l
o
we
r gr
ade
p
ar
t
s of t
he s
er
i
es
,
whi
ch ar
e par
t
i
c
ul
a
r
l
y we
l
l e
xp
os
e
d i
n
ch
er
t
s h
av
e yi
e
l
de
d La
t
e Car
bo
ni
f
er
o
us t
o Per
mi
a
n a
ges
the Lar
aquete ar
ea.
youngi
ng of the deposi
ts f
rom north t
o south.
The st
rata are f
ol
ded i
nto compl
i
cated i
nter
fer
ence
As r
ega
r
d
s r
a
di
ome
t
r
i
c d
at
i
n
g of t
h
e me
t
amor
ph
i
c compl
e
x,
Mu
ni
z
a
ga an
d ot
he
r
s (
1
9
72
)
i
nt
er
pr
e
t
e
d t
he 27
0
-
342 Ma
"
l
i
mi
t
i
n
g r
e
f
e
r
en
ce i
s
och
r
o
ns
" a
s t
h
e pr
o
ba
bl
e a
ge of me
t
a-
(
L
i
n
g a
n
d
F
o
r
s
y
t
h
e
,
1
9
8
7
)
a
t
Ma
d
r
e
d
e
Di
o
s
a
n
d
E
a
r
l
y
P
e
r
-
mi
an ages at n egaiada i
slano W 4 。),supporting the i
dea of a
p
at
t
er
ns
.
An e
ar
l
y Sl f
o
l
i
at
i
on as
s
o
ci
at
e
d wi
t
h u
pr
i
ght
f
o
l
ds
a
nd a l
at
e
r S2 f
o
l
i
a
t
i
on d
i
p
pi
n
g mo
der
at
el
y ea
s
t
war
ds ar
e
r
ec
og
ni
z
e
d.
Th
e gr
an
i
t
oi
d
s i
n
t
r
u
ded du
r
i
n
g S2 t
i
me.
Th
i
s
f
ol
i
at
i
o
n de
ve
l
o
ps pr
og
r
e
s
s
i
v
el
y t
owa
r
d
s t
he we
s
t
,
maki
ng i
t
d
i
f
f
i
c
ul
t
t
o r
ec
og
ni
z
e go,
an
d l
ea
vi
n
g Sl
as r
oot
l
es
s i
s
oc
l
i
n
al
mi
nor f
o
l
ds i
n t
h
e mi
c
r
o
l
i
t
h
ons bo
und
ed b
y S2
.
Thi
s i
s t
h
e
t
yp
i
c
al
s
t
r
uc
t
u
r
e of t
h
e c
h
ar
a
ct
e
r
i
s
t
i
c s
pot
t
ed mi
ca s
chi
s
t
mo
r
ph
i
s
m b
et
we
en 34
0 an
d 38
0
S.
Fu
r
t
he
r da
t
i
n
g of t
he
s
e
r
oc
ks ha
s pr
odu
ce
d t
he 26 Rb
-
Sr i
s
och
r
o
n,
一(
e
r
r
o
r
-
c
hr
o
ns
)
s
ho
wn i
n Fi
gu
r
e 1
,
as we
l
l as n
umer
ous K-
Ar mi
n
er
a
l
age
s
.
Al
l the i
sochrons
:
yi
el
d ages between 368 and 140 Ma f
or the
me
t
amor
ph
i
c c
omp
l
ex of t
he Coa
s
t Ra
nge s
o
ut
h of 34
0
S.
al
l al
ong the Coast Ranges
.
Th
e a
ge pa
t
t
e
r
n emer
gi
ng f
r
om t
h
es
e dat
a i
ndi
cat
es ol
der
At t
he Chonos Archi
pel
ago,
the str
uct
ure of t
he compl
ex i
s
ages for the easternmost r
ocks i
n any par
ti
cul
ar east
-west
s
ur
pr
i
s
i
n
gl
y s
i
mi
l
ar i
n i
t
s ov
er
al
l
pat
t
er
n
.
The eas
t
er
nmos
t
pr
of
i
l
e s
o
ut
h of 34
乍.Ea
s
t of Pi
c
hi
l
emu
,
t
he h
i
ghe
r gr
ade
porti
on i
s char
acter
i
zed by upri
ght ti
ght fol
ds wi
th a wel
l
si
l
l
i
mani
te gnei
s
ses are 368 Ma ol
d, t
he anda
l
usi
t
e
-st
aur
oli
te
SCHEMATI
C GENERALI
ZED CROSS SECTI
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EASTERN BELT
W ESTERN BELT
TERTIARY ANDQUATERNARY
WB
FI
ORDO SE
RRANO
F OO RD O
W AL KE R
iSL A
SA LA S
-
I
.
.
E
B
.
A
I
Q
U
E
r
s
N
E
s
S
'
l
CANALCNA
CAUUCC
GRANI
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MANITE GNEI
SS
METAGRAYWACKEA
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HYLUTE
SCHI
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META8ASI
TES
MELANGES
CHONOS ARCHI
PELAGO
DRILLI
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0
1
K .
卜---- ---‘.......
Figure 6: Sections across the metamorphic com-
plexes at Nahuelbuta Mountains (38*
S) and C
honos
Archipelago (44o
S)。
「八ULT 70NE
rocks west of them have a concor
dant 347 士 32 Ma meta-
mor
phi
c age and the blueschi
st
s at Pi
chi
l
emu 310 1 11 Ma.
Be
t
ween Co
nce
pc
i
6n an
d Val
di
v
i
a,
i
s
ochr
on
s r
a
nge be
t
we
en
290 and 330 Ma f
or rocks near the coas
t. The younger
nd m6
l
an
ge areas. A
d
ev
el
ope
d S,
axi
a
l
-
pl
ane c
l
e
av
ag
e,a
l
ow-
di
pp
i
n
g S2 cr
enul
ati
on cl
eavage (
Fi
g.
7
)
i
s progres- owar
ds t
he wes
t, where i
t becomes the
si
vel
y devel
oped t
pr
ed
omi
n
an
t s
t
r
uc
t
ur
al
f
e
at
u
r
e.
A bi
g di
f
f
er
enc
e be
t
wee
n
the two areas
, however
, i
s that the bathol
i
th t
o the east i
s
her
e Mes
ozoi
c-Cenozoi
c.
Geochr
onol
ogy
There ar
e a few i
ndi
cati
ons of t
he age of deposi
ti
on of the
p
r
ot
o
l
i
t
h t
o t
h
e met
amor
ph
i
c compl
ex
. At Lum aco. Tavera
(
19
83
)
des
cr
i
be
d t
h
e pr
e
s
en
ce of wor
m tubes of Gor
di
a? sp
and
nter-
sp. nov. which he i
pr
et
ed as i
ndi
cati
ng Si
l
uri
an depos
i
ti
on. Mi
l
l
er and Sprech-
man
n (
1
97
8
)
de
s
cr
i
b
e
d Dev
on
i
an b
r
ac
hi
opo
ds f
r
om
coarse
sandstones at I
sl
a Patr
anca. Ap
parent
l
y these w ere trans-
ng t
he
por
ted by turbi
di
t
y current
s to the deep ocean duri
Pun
t
a Bui
l
l
(
Ch
i
l
o6
)
,
Earl
y Devoni
an or Lat
e Si
l
uri
an. At Levi and other
s (1966) r
ecor
ded f
r
om r
ocks not i
n pl
ace
t
ri
l
obi
tes,
cr
i
noi
ds,
t
etr
acoral
s and nauti
l
oi
ds, whi
ch woul
d
i
ndi
cate a Devoni
an age.
Fr
om Ma
dr
e d
e Di
os
,
Do
u
gl
as
s an
d Ne
s
t
el
l (
1
97
6)
des
cr
i
be
d
a f
us
uli
ni
d as
sembl
age i
n massi
ve l
i
mestones,
i
ndi
cat
i
ve of
deposi
ti
on i
n warm waters dur
i
ng the Per
mi
an. Radi
ol
ari
an
186
EPI
SODES,
Vol
.
1
1
,
No
.
3,
Se
pt
emb
er 1
98
8
Car
b
oni
f
er
ous age
s ar
e t
ho
ug
ht t
o r
e
pr
es
e
nt t
he a
ge wh
en
S2 wa
s ge
ne
r
at
e
d i
n t
he r
ocks
,
an
d pha
s
e of i
ncr
ea
s
ed
c
on
ve
r
ge
nce r
at
e o
r of s
e
di
me
nt
a
r
y i
n
put i
nt
o t
he t
r
e
nch
.
At t
he Ch
on
os Ar
chi
pel
ago
,
o
l
de
r ag
es al
s
o t
en
d t
o be
e
nc
ou
nt
er
e
d i
n t
h
e e
as
t
er
nmo
s
t r
ock
s
,
i
n whi
c
h Sl i
s t
he
pr
e
domi
n
an
t s
t
r
uct
u
r
e
.
Yo
un
ger ag
e
s of 1
4
0士40 Ma a
nd
1
68 1 5 Ma ar
e obt
ai
ne
d i
n mo
r
e we
s
t
e
r
n r
o
ck
s wher
e S2 i
s
t
he pr
e
domi
na
nt
s
t
r
u
ct
u
r
e.
A c
ompl
et
e r
e
s
e
t
t
i
ng of t
he
Rb
-
Sr s
y
s
t
ems d
ur
i
n
g t
he d
eve
l
o
pme
nt
Of S2 ap
pea
r
s t
o hav
e
t
ak
en pl
a
ce,
a
nd t
hi
s ag
e pat
t
e
r
n i
s s
up
por
t
e
d by a f
ew K-Ar
whol
e rock age determi
nati
ons
.
South of t
he Tai
tao Peni
ns
ul
a,
the few determi
nati
ons
i
nc
l
ude Lat
e J
ur
a
s
s
i
c K-
Ara
ge
s on gl
au
eo
pha
ne s
c
hi
s
t
s ne
ar
Mad
r
e d
e Di
os
.
Cr
e
t
ace
ous mi
n
er
al
a
ges an
d Tr
i
a
s
s
i
c (
2
35 1
37 Ma
) Rb
-
Sr i
s
oc
hr
on
s at Cor
di
l
l
er
a Dar
wi
n (
Her
v6 e
t a
l
.
,
1
98
1
)
t
end t
o s
u
ppo
r
t t
he s
ou
t
hwa
r
d
-
you
ng
i
n
g pat
t
er
n
deduced f
rom t
he few pal
eont
ol
ogi
cal si
tes.
Thus,
the
met
amo
r
ph
i
c c
ompl
ex v
ar
i
e
s bot
h i
n t
he de
po
s
i
t
i
on
al
age of
t
h
e pr
ot
o
l
i
t
h an
d i
n i
t
s me
t
amor
p
hi
c a
ge
. The form er is
rom the Chonos
pr
oba
bl
y De
vo
ni
an or Si
l
ur
i
an (
or e
ar
l
i
er
?
)
f
Ar
chi
pe
l
ag
o t
o t
h
e nor
t
h
,
an
d La
t
e Carboniferous and
Per
mi
an s
out
h of the Tai
t
ao Peni
nsul
a. Th
e appar
ent east
t
o we
s
t y
ou
ngi
ng of
t
h
e met
amor
phi
s
m a
l
on
g t
h
e be
l
t i
s i
n
accor
dance wi
t
h successi
ve accreti
on f
rom the west, wi
th
upheaval of the r
ocks af
ter met
amor
phi
sm.
The 87
Sr
/
86
Sr i
ni
t
i
a
l
r
at
i
os of t
h
e r
ocks i
n t
h
e Pi
c
hi
l
e
mu
a
r
ea i
n
di
c
at
e h
i
gh
er v
al
ues (
0
.
71
2
)
i
n t
he e
as
t
er
n
met
amor
phosed turbi
di
t
e sequence, i
n agr
eement wi
th the
i
dea that the el
asti
c mater
i
al com es f
r
om a cont
i
nental
s
o
ur
ce i
n t
h
e Sou
t
h Amer
i
ca
n cr
at
on.
Wes
t
e
r
l
y r
o
cks
,
i
ncl
udi
ng the pi
l
l
ow basal
ts and meta-chert
s, have l
ower
va
l
u
es (
0.
7
06
)
,
i
nd
i
ca
t
i
n
g t
he gr
eat
er i
n
f
l
u
en
ce of oc
ea
ni
c
materi
al
s. Sti
l
l l
ower val
ues (
0.704-0.705) are obt
ai
ned
fr
om the meta-bas
i
tes and met
a-pel
i
t
es ass
oci
ated wi
t
h the
mas
s
i
ve s
ul
phi
de
s i
n t
he Temu
co
-Va
l
di
v
i
a ar
e
a.
As
s
umi
n
g
no met
as
omati
C Dr
ocesses duri
nz thei
r metamor
r
)hi
sm. and a
。,z
sr/- z
:
ir vaiue ot u.iuzo ior tne upper m antie irom wni
cn
thes
e rocks wer
e deri
ved, a maximum age for t
he basal
ti
c
pr
otol
i
th woul
d be around 400 Ma, that i
s Si
l
uri
an.
Geol
ogi
cal Evol
uti
on
The met
amor
phi
c compl
e
x of t
h
e Co
as
t
Ran
ges of c
en
t
r
a
l
a
nd s
ou
t
he
r
n Ch
i
l
e r
ec
or
ds ge
o
l
ogi
c
al
pr
o
ce
s
s
e
s al
on
g t
he
s
out
h an
d s
ou
t
hwe
s
t
e
r
n ma
r
gi
n o
f Gon
dwan
a dur
i
ng t
h
e l
at
e
Pal
eozoi
c. Thi
ck tur
bi
di
te sequences accumul
ated on the
oc
ean f
l
oo
r ad
j
a
ce
nt t
o t
he con
t
i
n
ent
,
pr
ob
ab
l
y f
r
om as
ea
r
l
y a
s t
he S
i
l
ur
i
a
n bu
t mai
n
l
y,
i
t s
e
ems
,
d
ur
i
ng t
he
De
vo
ni
a
n.
Thes
e t
hi
ck s
e
di
men
t
ar
y det
r
i
t
al
s
e
que
nc
es of
co
nt
i
nen
t
a
l
or
i
gi
n i
n
di
c
at
e t
he pr
es
e
nc
e of an e
me
r
gi
ng
conti
nent wi
th acti
ve er
osi
onal and sedi
ment tr
ansport
pr
oce
s
s
e
s t
owa
r
d
s t
h
e f
r
i
n
gi
n
g o
cea
n.
The a
bs
e
nc
e of
Si
l
uri
an or Devoni
an grani
t
oi
d bel
ts suggest
s that subducti
on
pr
ocesses were not ver
y acti
ve dur
i
ng these per
i
ods: a
passi
ve t
ype of cont
i
nent
al mar
gi
n may have exi
sted here.
f
l
o
or
ed mar
gi
n
a
l ba
s
i
n
,
wh
i
ch al
l
owed Cr
et
a
ceo
us met
a-
mo
r
pb
i
s
m t
o t
ak
e p
l
ac
e af
f
ec
t
i
n
g pr
e
vi
o
us
l
y met
amor
ph
os
e
d
rocks of the s
ubducti
on compl
ex.
The constr
ucti
ve phas
e of the subduct
i
on compl
ex i
nvol
ved
t
he gen
er
at
i
on of a wi
de a
r
e
a of a
cc
r
et
ed mat
e
r
i
a
l
,
i
nc
l
u
di
n
g i
s
l
an
d ar
cs a
nd s
edi
me
nt
ar
y de
pos
i
t
s of i
n
t
er
v
e
ni
n
g
basi
ns
. Thi
s i
s a si
tuati
on si
mi
l
ar t
o t
he pres
ent day West
-
er
n Pac
i
f
i
c mar
gi
n
,
wh
er
e c
ompl
i
c
at
ed p
at
t
er
n
s of i
s
l
an
d
ar
c
s an
d oc
ea
n r
i
d
ge
s c
on
t
r
a
s
t wi
t
h t
h
e s
i
mpl
e l
i
n
e
ar vo
l
-
cani
c bel
t of Sout
h Ameri
ca.
The characteri
sti
cs of t
he l
at
e
Pal
eozoi
c envi
ronment i
n Chi
l
e coul
d be descr
i
bed as t
hos
e
of a Mar
i
an
a
-t
y
pe c
ont
i
ne
nt
al
ma
r
gi
n du
r
i
n
g t
he "
c
on
-
s
t
r
uct
i
ve
" pha
s
e of an accr
et
i
on
ar
y p
r
i
s
m.
The ch
an
ge o
f
regime to a destr
uct
i
ve phase of the accr
eti
onar
y pr
i
sm,
ma
r
ke
d by t
he ge
ne
r
at
i
on of t
he S2 f
ol
i
a
t
i
o
n a
nd t
h
e
i
nt
r
us
i
on of t
he gr
a
ni
t
oi
d
s
,
mi
ght
be t
he r
ec
or
d o
f t
he
i
n
i
t
i
at
i
on of a Chi
l
e
an-
t
y
pe r
egi
me f
o
r t
h
e co
nt
i
n
en
t
a
l
mar
gi
n i
n t
h
e c
l
as
s
i
f
i
c
at
i
o
n of Uye
d
a (
1
9
82
)
.
Af
t
e
r t
he d
i
ac
hr
on
ous hi
gh
-
PT met
amor
ph
i
s
m,
t
h
e me
t
a
-
mor
phi
c c
ompl
e
x was r
api
dl
y u
pl
i
f
t
e
d an
d er
ode
d t
o l
ev
e
l
s
s
i
mi
l
ar t
o t
h
e pr
e
s
e
nt ex
po
s
ur
es by La
t
e Tr
i
a
s
s
i
c t
i
mes i
n
t
he n
or
t
h a
nd pr
o
bab
l
y by t
he Ear
l
y Cr
e
t
a
ceo
us i
n t
he
s
o
ut
h.
K-
Ar mi
ne
r
a
l age
s ar
e o
nl
y a l
i
t
t
l
e y
oun
ge
r t
ha
n t
he
Rb一r i
s
o
chr
on a
ges
,
pr
o
ba
bl
y i
n
di
c
at
i
n
g r
api
d u
pl
i
f
t j
us
t
af
t
e
r t
h
e ge
ner
at
i
on Of S2.
The a
ccr
et
i
on was di
s
pl
ac
ed
west
wards so t
hat al
ong t
he present coast
l
i
ne no outcr
ops of
a Cen
oz
oi
c a
ccr
et
i
on
ar
y compl
e
x exi
s
t
.
I
f p
r
es
ent
,
t
he
y a
r
e
of
fshor
e, i
n contr
ast to t
he si
tuat
i
on i
n Barbados and some
i
s
l
and ar
cs of t
he wes
t Paci
f
i
c where l
at
e Cenozoi
c accre-
t
i
ona
r
y pr
i
s
ms ou
t
cr
op
.
Mu
ni
z
a
ga an
d ot
her
s (
i
n pr
e
s
s
)
s
u
gg
es
t
t
h
at t
e
ct
oni
c e
r
os
i
o
n of t
he c
ont
i
n
ent
a
l mar
gi
n i
n
t
he no
r
t
h
er
n par
t of t
he compl
ex t
oo
k pl
a
ce f
r
om t
he Me
s
o
-
zoi
c to the Cenozoi
c.
Th
e pe
l
agi
c s
e
qu
en
ce was acc
r
et
e
d t
o t
he c
ont
i
ne
nt b
ef
or
e
the Earl
y Carboni
f
er
ous i
n t
he nor
th and af
ter the Ear
l
y
Permi
an i
n the s
out
h, duri
ng a const
ructi
ve phase of the
ac
cr
et
i
o
nar
y pr
i
s
m (
Da
vi
d
s
o
n et a
l
.
,
1
9
87
)
. M61
an
ges
dev
el
ope
d bet
we
e
n t
e
ct
oni
c we
dg
es of t
ur
b
i
di
t
e mat
er
i
al
.
ncor
por
ated i
nt
o the
Dur
i
n
g t
h
i
s ph
as
e
,
o
ce
ani
c r
ock
s wer
ei
ent
i
ng ei
ther a
cc
r
et
i
on
ar
y pr
i
s
m f
r
om t
h
e we
s
t
, repres
m ateri
al g
enerated at oceanic ridges or i
sl
and ar
cs
, or
tectonic sl
i
ces of the ocean fl
oor s
uppor
ti
ng the turbi
di
t
e
s
equence.
Thes
e oceani
c r
ocks wer
e met
amor
phos
ed i
n the
accr
eti
onary pri
sm,
and l
ow i
ni
ti
al Sr rat
i
os i
ndi
cate that
the ti
me of the extr
usi
on of pi
l
l
ow basal
ts was not much
ear
li
er than thei
r met
amor
phi
sm. The east
ernmost and
pr
oba
bl
y t
hi
c
ke
s
t pa
r
t of t
he ac
cr
et
i
o
na
r
y s
e
qu
en
ce wa
s
af
f
ec
t
e
d b
y a l
on
g l
o
w-PT me
t
amor
phi
s
m,
be
gi
n
ni
n
g i
n t
he
north.
I
n the Late Car
boni
f
erous,
the tect
oni
c regi
me changed
dr
amati
cal
l
y i
n the north,
gi
vi
ng ri
se to the devel
opment of
hi
ghe
r PT me
t
amor
ph
i
s
m an
d hi
gh s
t
r
a
i
n d
ur
i
ng t
h
e gen
er
-
at
i
on of
S2
.
Th
i
s "
d
es
t
r
uc
t
i
v
e p
has
e" on t
he a
ccr
et
i
on
ar
y
pr
i
sm may corres
pond t
o an i
ncrease i
n shear st
rai
n al
ong
t
h
e b
as
e of t
h
e ac
cr
e
t
i
onar
y pr
i
s
m,
a phe
nomen
on t
ha
t co
ul
d
hav
e be
en e
nh
an
ce
d by a f
as
t
er c
onv
er
gen
ce r
at
e
,
a r
e
duc
ed
s
e
di
ment
ar
y i
n
p
ut or a d
ecr
ea
s
e i
n p
or
e pr
es
s
ur
e t
h
at
resul
t
ed i
n a st
r
ong mechani
cal coupl
i
ng between the
oceani
c pl
ate and the accr
eti
onary wedge. At thi
s st
age,
the tectoni
c condi
t
i
ons l
ed t
o buri
al of t
he r
ocks deep i
n the
l
i
t
h
os
pber
e,
g
i
vi
n
g r
i
s
e t
o pr
o
ces
s
e
s cu
l
mi
n
at
i
n
g i
n t
h
e
gene
r
a
t
i
o
n of t
he h
u
ge l
at
e Pal
e
oz
oi
c ma
gmat
i
c be
l
t
.
Thi
s
b
el
t t
ur
ns wes
t
war
d ar
o
un
d 380
S
,
t
r
en
di
n
g s
o
ut
h
ea
s
t
war
d
s
a
l
on
g n
or
t
h
er
n Pat
a
gon
i
a,
t
r
a
ci
n
g o
ut t
h
e ol
d co
nt
i
ne
nt
a
l
m argin.
The s
ame process was acti
ve i
n the s
outher
n part on t
he
Cor
di
l
l
er
a Darwi
n wi
th the generati
on of an abort
ed ocean-
The me
t
amor
ph
i
c compl
e
x of t
he Co
as
t
Ran
ges of s
ou
t
h
-
cent
ral Chi
l
e probabl
y ori
gi
nat
ed by subducti
on and accr
e-
ti
on fr
om west t
o east
, rel
at
ed to the consumpti
on of a
pr
oto
-Paci
f
i
c Oceani
c pl
at
e. However,
l
i
tt
l
e i
s known about
t
he l
at
er hi
s
t
or
y of d
i
s
pl
ac
emen
t o
f t
he s
u
b
duct
i
o
n c
omp
l
ex
once i
t was i
ncor
porat
ed t
o the conti
nental overr
i
di
ng
pl
a
t
e
.
Re
cen
t pa
l
eoma
gne
t
i
c s
t
u
di
e
s ar
o
un
d t
he Li
qu
i
ie
f
-
Of
aui meL
r
afaul
t (
Gar
ci
a. 1987)
. whi
ch extends to t
he east of
tne uoast i
tange i
)
etween ju ana 4a z
}
nave snown t
nat 4uu
t
o 5
0
0 km of de
xt
r
al
s
t
r
i
k
e-
s
l
i
p mo
vemen
t mi
gh
t hav
e
occur
red al
ong i
t, di
s
pl
aci
ng the coast
al metamor
phi
c com-
pl
ex nort
hwar
d.
I
t i
s i
nt
eresti
ng to poi
nt out that at thi
s l
at
i
tude,
rocks
the c
si
mi
l
ar t
o those outcr
oppi
ng
oast
al areas appear
ous posi
t
i
on
La
go Ge
ne
r
a
l
Ca
r
r
er
a (
Fi
g.
1 in a n anomal
in ),
c
omp
l
ex af
t
er t
he Per
mi
an
,
as i
n
di
c
at
e
d b
y t
he i
n
vo
l
veme
nt
of r
o
ck
s of t
h
a
t age i
n t
h
e acc
r
et
i
o
nar
y wed
ge,
a
nd per
ha
ps
i
nt
o t
he J
ur
as
s
i
c,
as i
n
di
c
at
e
d b
y t
he Rb
一r i
s
oc
hr
ons at
t
h
e
Cho
no
s Ar
ch
i
pe
l
a
go
.
A s
pec
i
a
l t
e
ct
oni
c s
i
t
u
at
i
on exi
s
t
e
d i
n
F
igu
re 7:
Cre
nul
at
io
n cle
av
ag
e (
S2) i
n ba
nd
ed
phyllite at Teresa Island,
Chonos Archipelago.
EPI
SODES, Vol
. 11, No. 3,
September 1988
187
t
he gener
al or
gani
zati
on of t
he compl
ex. Thi
s mi
ght,
p
er
h
a
ps
,
b
e t
h
e r
e
s
ul
t
o
f dou
bl
i
ng t
h
e comp
l
ex b
y o
bl
i
q
ue
s
l
i
ci
ng and nor
thwards tr
ans
por
t of the western sl
i
ce al
ong
t
he conti
nent
al mar
gi
n. However
, t
hi
s i
s one probl
em to be
r
es
o
l
v
e
d b
ef
o
r
e co
nf
i
den
t p
al
e
og
eo
gr
a
phi
c r
ec
ons
t
r
u
ct
i
on
s
f
or the l
ate Pal
eozoi
c f
or the area can be pr
oduced.
Acknowl
edgement
s
The resul
ts pr
esent
ed here wer
e made possi
bl
e by Grant
E-2
45
7 of t
he De
par
t
amen
t
o de I
nve
s
t
i
ga
ci
6
n y Bi
b
l
i
ot
e
ca
s
of t
he Uni
versi
ty of Chi
l
e, and 1332 of FONDECYT,
as wel
l
as f
i
e
l
d and l
ab
or
a
t
o
r
y wor
k a
nd di
s
c
us
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i
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e
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vo en un pr
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188
EPI
SODES,
Vol
. 11,
No. 3, Sept
ember 1988
★
★
★