Artículo en PDF
How to cite
Complete issue
More information about this article
Journal's homepage in redalyc.org
Sistema de Información Científica
Red de Revistas Científicas de América Latina y el Caribe, España y Portugal
doi: 10.5027/andgeoV42n2-a02
Andean Geology
www.andeangeology.cl
Andean Geology 42 (2): 173-189. May, 2015
Tephrochronology of the upper Río Cisnes valley (44°S), southern Chile
Charles R. Stern
1
, María Eugenia de Porras
2
, Antonio Maldonado
2,3
1
Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309-0399, USA.
charles.stern@colorado.edu
2
Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad de La Serena, Raúl Bitran 1305, La Serena, Chile.
meugenia.deporras@ceaza.cl
3
Departamento de Biología Marina, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile.
amaldona@userena.cl
ABSTRACT.
Based on their petrography and chemistry, 18 tephra analyzed from two lake and bog cores and one outcrop
in the upper Río Cisnes valley are believed to have been derived from nine different eruptions of the Mentolat volcano,
four of the Melimoyu volcano, and one from the Hudson volcano. Some of these tephra correlate chronologically and
petrochemically with previously documented large eruptions of these volcanoes, including the Late-Glacial Ho eruption
of Hudson (17,340 cal yrs BP), the mid-Holocene MEN1 eruption of Mentolat (7,710 cal yrs BP), and the Late-Holocene
MEL2 eruption of Melimoyu (1,680 cal yrs BP). A Melimoyu-derived tephra from the outcrop occurs in glacial-lacustrine
sediments and is considered to pre-date the Last Glacial Maximum (>19,670 cal yrs BP). The data suggest that none of
the tephra were produced by explosive eruptions of the Maca, Cay and Yanteles volcanoes.
Keywords: Tephra, Tephrochronology, Tephrostratigraphy, Volcanism, Andes, Chile.
RESUMEN. Tefrocronología en curso superior del valle del río Cisne (44°S), Chile Austral.
Dieciocho tefras prove-
nientes de testigos de un lago y un mallín, junto a un perfil expuesto en el alto valle del río Cisnes fueron caracterizadas
sobre la base de su petrografía y química y corresponderían a nueve diferentes erupciones del volcán Mentolat, cuatro del
volcán Melimoyu y una del volcán Hudson. Algunas de estas tefras se correlacionan cronológica y petroquímicamente
con grandes erupciones de estos volcanes previamente documentadas, incluyendo la erupción Ho del volcán Hudson
(Tardiglacial, 17.340 años cal. AP), la erupción MEN1 del volcán Mentolat (Holoceno medio, 7.710 años cal. AP) y la
erupción MEL2 del volcán Melimoyu (Holoceno tardío, 1.680 años cal. AP). Una tefra perteneciente a la erupción del
volcán Melimoyu, hallada en un perfil expuesto en un contexto de depósitos glaciolacustres, tiene una edad (>19.670
años cal. AP) que precede al término del Último Máximo Glacial en Patagonia Central. Los datos sugieren que ninguna
de las tefras fueron producidas por erupciones explosivas de los volcanes Maca, Cay y Yanteles.
Palabras clave: Tefra, Tefrocronología, Tefrostratigrafía, Volcanismo, Andes, Chile.
174
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
1. Introduction
Tephra layers in sediment cores from lakes and
bogs provide information on the history of explosive
volcanic eruptions from nearby volcanoes, and thus a
basis for evaluating the possibilities for and potential
effects of future eruptions. The identification, petro-
chemical description and correlation of synchronous
volcanic tephra layers over large geographic areas
and in different environmental settings also provides
a stratigraphic correlation tool for a broad range of
disciplines (Lowe, 2011; Fontijn
et al
., 2014), including
archaeology (Prieto
et al
., 2013), palaeoclimatology
and palaeogeomorphology (García
et al
., 2015, this
volume).
Here we characterize both petrochemically and
chronologically multiple Late-Glacial and Holocene
tephra layers in two sediment cores from the area of
the upper Río Cisnes valley (Figs. 1 and 2); one core
from Lago Shaman (Fig. 3; de Porras
et al
., 2012),
and one core from Mallín El Embudo (Fig. 4; de
Porras
et al
., 2014). With this information we attempt
to correlate tephra layers between the cores and to other
previously described tephra in the region, and identify
for each layer their possible source volcano, which
potentially include the Yanteles, Melimoyu, Mentolat,
Maca, Cay and Hudson stratovolcanoes, as well as
numerous small monogenetic cones located between
Puyuhuapi and Palena (Fig. 1). We also describe one
sample of tephra that outcrops in glacial-lacustrine
sediments, and pre-dates the Last Glacial Maximum.
2. Background
Bedrock geology in the upper Río Cisnes valley
consists of plutons of the Patagonia batholith and Lower
FIG. 1. Regional map showing the location, in the box, of the area of Alto Río Cisnes (Fig. 2) from which tephra samples were studied,
and both stratovolcanoes (larger triangles) and the Puyuhuapi and Palena groups of minor monogenetic mafic eruptive cones
(MEC: smaller solid triangles) in the southern SSVZ (Stern, 2004; Stern
et al
., 2007).
175
Stern et al. / Andean Geology 42 (2): 173-189, 2015
Cretaceous sediments overlain by Quaternary deposits,
which include the materials examined in this study. de
Porras
et al
. (2012, 2014) describe in some detail the
environmental setting of the two cores. Lago Shaman is
located in the semi-arid forest-steppe ecotone just west
of the Chile-Argentina border, which at this latitude
corresponds to a moraine complex formed during
the last Late-Glacial Maximum (LGM; Fig. 2). This
area became ice free at or soon after 19,000 BP, and
the deepest organic layer dated, from 599 cm depth
in the 613 cm long Lago Shaman core (LS0604A;
Fig. 3), yields an age of 18,950 cal yrs BP (Table 1).
In contrast, the Mallín El Embudo core is located in
a wetter forested area ~35 km to the southwest of
Lago Shaman (Fig. 2), west of a small frontal moraine
interpreted to have formed by a Late-Glacial glacial
advance before approximately 13,000 BP (de Porras
et al
., 2014). The oldest age obtained, from 809 cm
deep in this 844 cm long composite core (EE0110A
and B; Fig 4) was 12,997 cal yrs BP.
These two cores were collected with the purpose
of providing a pollen record and its implications for
the changing climate in this region since the end of
the last glaciation (de Porras
et al
., 2012, 2014), as
well as a charcoal record and its implication for the
history of fires caused possibly by climate change,
volcanic activity and/or the human occupation of
the valley, which dates back to 11,500 BP (Méndez
and Reyes, 2008; Méndez
et al
., 2009; Reyes
et al
.,
2009). Both cores contain clastic layers which are in
most cases tephra (Figs. 3 and 4). The Lago Shaman
core contains more numerous tephra, which may
possibly reflect the fact that Lago Shaman occurs in
an open arid area with no vegetation to interfere with
tephra fall and wind redistribution of tephra, while
Mallín El Embudo occurs in a wetter environment
with forest cover. One other tephra sample (Cisnes
263A; Fig. 5) was also collected from an outcrop of
glacial-lacustrine sediment at Las Barrancas (Fig. 2).
It occurs ~3 meters below the contact, dated as
FIG. 2. Map of the location of the Lago Shaman and Mallín El Embudo cores in relation to the LGM moraine complexes along the
Chile-Argentina border and the frontal moraine formed during a Late-Glacial glacial advance in the upper Río Cisnes valley
(de Porras
et al
., 2012, 2014). Also shown is the location at Las Barrancas of the Late-Glacial glacial-lacustrine sediments
containing the outcrop of the >19,670 BP tephra sample Cisnes 263A.
176
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
19,670 cal yrs BP, between these and overlying
fluvial sediments (Fig. 5).
Previous tephrochronologic studies in this area
of the southern Southern Volcanic Zone (SSVZ) of
the Andes include those of Naranjo and Stern (1998,
2004), Mella
et al
. (2012) and Weller
et al
. (2014).
These studies indicate that all the potential source
volcanoes for the tephra in the upper Río Cisnes valley
(Yanteles, Melimoyu, Maca, Cay and Husdon) have
had Holocene explosive eruptions producing locally
or regionally distributed tephra falls (Naranjo and
Stern, 1998, 2004; Mella
et al
., 2012; Weller
et al
.,
FIG. 3. X-ray image of Lago Shaman core (de Porras
et al
., 2012). Bright white layers are either sand or tephra and darker areas are
organic rich sediments.
177
Stern et al. / Andean Geology 42 (2): 173-189, 2015
2014). Melimoyu, Mentolat and Hudson have summit
craters/calderas possibly formed in association with
these events. Melimoyu and Hudson are two of the
largest volcanic edifices in the SSVZ (Völker
et al
.,
2012). Also the many small monogenetic cones in
the region have produced basaltic scoria deposits
as well as lava flows (López-Escobar
et al
., 1995a;
Gutiérrez
et al
., 2005; Watt
et al
., 2013; Vargas
et al
.,
2013), but the potential regional extent of distribution
of tephra from these generally small volume mafic
eruptions is uncertain
The previously published interpretations of the
source volcanoes of tephra in the SSVZ were made in
part on the basis of tephra major element chemistry
compared with published whole rock chemistry of
samples of lavas from the volcanoes of the SSVZ
(Naranjo and Stern, 2004; Weller
et al
., 2014). In
a similar fashion, the possible sources of seven of
the tephra in the Lago Shaman core were made on
the basis of bulk tephra trace-element chemistry
compared to published whole-rock trace-element
analysis of lava samples from the SSVZ volcanoes
to the west of the core site (de Porras
et al
., 2012).
These trace-element data suggest Melimoyu, Mentolat
and Hudson volcanoes as the sources for these seven
tephra (de Porras
et al
., 2012; Weller
et al
., 2014).
Since spatial coverage is still too restricted to
allow for the construction of tephra isopach maps,
which is the most conclusive way to identify source
volcanoes for tephra, this paper also employs the
geochemical approach of comparing tephra chemis-
try with the published data concerning the volcanic
rocks associated with the different SSVZ centers
(Fig. 6) to identify possible tephra source volcanoes
of the tephra. Information concerning the chemistry
of the magmas erupted from the volcanic centers in
the SSVZ has been published by Stern
et al
. (1976),
Futa and Stern (1988), López-Escobar
et al
. (1993,
1995a), D’Orazio
et al
. (2003), Gutiérrez
et al
. (2005),
Kratzmann
et al
. (2009, 2010), Watt
et al
. (2013) and
Weller
et al
. (2014). Samples from SVZ volcanoes
in south-central Chile, and specifically the SSVZ
FIG. 4. X-ray image of Mallín El Embudo core (de Porras
et al
., 2014). Bright white layers are either sand or tephra and darker areas
are organic rich sediments.
178
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
TABLE 1. DEPTH IN CM OF TEPHRA AND
14
C AGE DATES IN CAL YRS BP FROM THE LAGO SHAMAN (DE PORRAS
ET AL
., 2012) AND MALLÍN EL EMBUDO (DE PORRAS
ET AL
., 2014) CORES.
Lago Shaman
tephra
depth cm
~age*
Source*
eruption*
age*
a
64-70
1,440
Melimoyu
MEL2
1,680
85
1,827±40
-
-
-
b
94
2,140
Mentolat
-
-
c
104
2,490
Mentolat
-
-
122
3,111±40
-
-
-
d
160
3,720
Mentolat
-
-
e
170
3,880
Mentolat
-
-
195
4,275±50
-
-
-
f
207
4,610
Melimoyu
-
-
g
255
8,280
Melimoyu
-
-
260
8,357±40
-
-
-
h
261
8,400
Mentolat
-
-
i
270
8,800
Mentolat
MEN1
7,710
316
10,824±70
-
-
-
m
326
11,140
Mentolat
-
-
392
13,241±40
-
-
-
489
18,474±100
-
-
-
q
533
18,665
Mentolat
-
-
v
570
18,820
Hudson
Ho
17,340
y
598
18,940
Mentolat
MENo
>17,340
599
18,951±50
-
-
-
Mallín El Embudo
tephra
depth cm
~age*
source
eruption*
age*
25
94±20
-
-
-
154
1,453±30
-
-
-
162
1,743±40
-
-
-
a
173-179
2,090
Melimoyu
MEL2
1,680
266
4,492±40
-
-
-
b
255-278
4,810
Melimoyu
-
-
h
549
9,010
Mentolat
MEN1
7,710
585
9567±30
-
-
-
699
11179±30
-
-
-
740
11,302±69
-
-
-
j
746
11,450
Mentolat
-
-
809
12,997±35
-
-
-
CIS 263-A
-
>19,670
Melimoyu
-
-
*Measured
14
C age dates in cal yrs BP; ~ages for tephra interpolated from measured ages; possible sources based on tephra chemistry
(Table 3); ages of previously documented eruptions from Naranjo and Stern (2004) and Weller
et al
. (2014).
179
Stern et al. / Andean Geology 42 (2): 173-189, 2015
volcanoes, fall into different and distinguishable
chemical groups (Fig. 6). Two of these groups have
previously been termed Type-1, or Low Abundance,
and Type-2, or High Abundance magmas (Hickey
et
al
., 1986, 1989, 2003; López-Escobar
et al
., 1993,
1995a, 1995b).
These two different magma types
are distinguished by their different concentrations
of the incompatible elements K
2
O (Fig. 6a), Rb, Ti,
Ba. Zr, Sr, Y, Nb and La, as well as La/Yb and Ba/
La ratios, over a large range of SiO
2
contents from
basalts to dacites. In the SSVZ, Maca, Cay and
Yanteles stratovolcanoes (Fig. 6), and the Palena
group of monogenetic cones are Type-1 or Low
Abundance volcanoes (López-Escobar
et al
., 1993,
1995a; D’Orazio
et al
., 2003; Gutiérrez
et al
., 2005;
Carel
et al
., 2011; Watt
et al
., 2013), while Hudson
and Melimoyu volcanoes (Fig. 6) and the Puyuhaipi
group of monogenetic cones are Type-2 or High
FIG. 5.
A.
Photo of the ~6 cm thick Cisnes 263A tephra in glacial-lacustrine sediment formed during the last glaciation;
B.
This tephra
occurs ~3 meters below the contact, dated as 19,670 cal yrs BP, between the glacial-lacustrine clay and overlying fluvial sediments.
180
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
FIG. 6.
A.
SiO
2
versus
K
2
O for samples of both lavas and tephra from Yanteles, Melimoyu, Maca, Cay and Hudson volcanoes (Futa
and Stern, 1988; López-Escobar
et al
., 1993; Naranjo and Stern, 1998, 2004; D’Orazio
et al
., 2003; Gutiérrez
et al
., 2005;
Kratzmann
et al
., 2009, 2010), illustrating the separation of these samples into what have previously been termed High, Low
and Very Low Abundance magma types (Hickey
et al
., 1986, 1989, 2003; López-Escobar
et al
., 1993, 1995a, 1995b; Sellés
et al
., 2004; Watt
et al
., 2011). Line separating the fields of High-, Medium-, and Low-K convergent plate boundary magmas
are from Peccerillo and Taylor (1976);
B.
Ti
versus
Rb for the SSVZ volcanoes and each individual tephra from the upper
Río Cisnes valley (Table 3);
C.
Sr
versus
Ba for the SSVZ volcanoes and tephra from the upper Río Cisnes valley (Table 3).
181
Stern et al. / Andean Geology 42 (2): 173-189, 2015
Abundance centers (López-Escobar
et al
., 1993,
1995a; Naranjo and Stern, 1998, 2004; Kratzmann
et al
., 2009, 2010; Carel
et al
., 2011). The Palena
and Puyuhuapi group basalts are not plotted in
figure 6 because they both contain abundant olivine
and lack orthopyroxene and amphibole, and are the
-
refore petrologically distinct from the tephra in the
upper Río Cisnes valley described below (Table 2).
Although samples from different Type-1 Low
Abundance volcanoes are generally similar to each
other, a specific exception in this southern part of the
SSVZ is the Mentolat volcano, which at any given
SiO
2
content has lower K
2
O (Fig. 6a; López-Escobar
et al
., 1993; Naranjo and Stern, 2004; Watt
et al
.,
2011), Rb, Ti (Fig. 6b), Sr, Ba (Fig. 6c) and La/Yb
(Watt
et al
., 2011), similar to other unusually or Very
Low Abundance samples from Nevado de Longaví
(Sellés
et al
., 2004), Calbuco (López-Escobar
et al
.,
1995b) and Huequi (Watt
et al
., 2011) volcanoes
further to the north. Like Mentolat, all these other
Very Low Abundance centers are characterized by
the presence of amphibole in their eruptive products
(López-Escobar
et al
., 1993, 1995b; Sellés
et al
.,
2004; Watt
et al
., 2011).
3. Methods
X-ray images of the cores (Figs. 3 and 4) were
taken to allow for better visual identification of the
tephra deposits and to provide a means of stratigraphic
correlation of the tephra layers between the cores.
The white layers in these images, arbitrarily termed
a though z in the Lago Shaman core (Fig. 3) and a,
b, g, h and j in the Mallín El Embudo core (Fig. 4),
are the denser lithologies, often tephra deposits,
but in some cases sand, and the darker layers are
less dense organic-rich lacustrine sediments. The
chronology of the tephra in the trenches and cores
is constrained by AMS radiocarbon dates of organic
material in the overlying and underlying sediments
TABLE 2. MAIN PETROGRAPHIC FEATURES OF THE TEPHRA FROM THE UPPER RÍO CISNES VALLEY.
tephra
components
Glass color
Vesicles
Microlites
a
Gl>Plag>Cpx>Opx
Brown
Few, round
Plag
b
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
c
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
d
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
e
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
f
Gl>Plag>Cpx>Opx>Ol
Brown
Few, round
Plag
g
Gl>Plag>Cpx>Opx
Brown
Few, round
Plag
h
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
i
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
m
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
q
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
v
Gl>>Plag>Opx
Brown to Tan
Abund, stretched
-
y
Plag>Gl>Opx>Cpx>Amph>>Ol
Clear
Abund, round
-
Mallín El Embudo
tephra
components
Glass color
Vesicles
Microlites
a
Gl>Plag>Cpx>Opx
brown
Few, round
Plag
b
Gl>Plag>Cpx>Opx>Ol
brown
Few, round
Plag
h
Plag>Gl>Opx>Cpx>Amph
Clear
Abund, round
-
j
Plag>Gl>OPx>Cpx>Amph
Clear
Abund, round
-
CIS 263-A
Gl>Plag>Cpx>Opx
brown
Few, round
Plag
Gl:
glass;
Plag:
plagioclase;
Cpx:
clinopyroxene;
Opx:
orthopyroxene;
Amph:
amphibole;
Ol:
olivine;
Abund:
abundant.
182
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
(Fig. 7; Table 1; de Porras
et al
., 2012, 2014). Ra-
diocarbon dates were converted to calendar years
before present (cal yrs BP) using the CALIB 5.01
program (Stuiver
et al
., 1998).
The tephra samples were washed to remove
any organic matter, and then dried and sieved to
remove any coarse fraction material not volcanic
in origin. After cleaning, the bulk tephra samples
were mounted on petrographic slides and examined
under a petrographic microscope in order to identify
petrographic characteristics such as tephra glass co-
lor and morphology (Fig. 8) and the proportion and
identity of mineral phases (Table 2). Trace-element
data for bulk tephra samples were determined using
an ELAN D CR ICP-MS (Table 3; Saadat and Stern,
2011). Trace-element compositions are considered
accurate to ±5% at the level of concentrations in
these samples, based on repeated analysis of stan-
dard rock samples of known composition (Saadat
and Stern, 2011).
4. Results
A summary of some of the most obvious petrogra-
phic features of each of 13 tephra samples from the
Lago Shaman core, four from the Mallín El Embudo
core, and one other outcrop sample (Cisnes 263A),
are presented in Table 2 and tephra trace-element
chemistry are presented in Table 3. The chemical
and petrologic characteristics of each tephra, and
the reasons for suggesting a possible source volcano,
are discussed below in chronological order from the
youngest to the oldest.
4.1. Tephra ‘a’ from both cores
The youngest tephra in both cores, tephra ‘a’
(Figs. 3 and 4; Tables 1-3), is approximately 6 cm
thick in each core and in both consists dominantly
of identical appearing brown glass with a few round
and only rarely stretched vesicles and containing
FIG. 7. Age
versus
depth in the core of the different tephra analyzed from the Lago Shaman and Mallín El Embudo cores. Also shown
are the ages for tephra MEL2 from Melimoyu (Naranjo and Stern, 2004) which may correlate with tephra ‘a’ in both cores,
MEN1 from Mentolat (Naranjo and Stern, 2004; Stern
et al
., 2013) which may correlate with tephras ‘i’ in Lago Shaman and
‘h’ in Mallín El Embudo, and Ho from Hudson which correlates with tephra ‘v’ in Lago Shaman (Weller
et al
., 2014).
183
Stern et al. / Andean Geology 42 (2): 173-189, 2015
occasional plagioclase microlites (Fig. 8A). Pheno-
crysts of plagioclase, which are the most abundant
along with both clinopyroxene and orthopyroxene,
are similar in size to the glass shards. The samples
from both cores have nearly identical chemistry,
which is similar to the High Abundance types of
rocks erupted in the southern SVZ by the Hudson
and Melimoyu volcanoes (Fig. 6) and Puyuhuapi
cones (López-Escobar
et al
., 1993, 1995a). Howe-
ver, olivine is abundant in and orthopyroxene has
not been reported from the Puyuhuapi group basalt
samples (López-Escobar
et al
., 1995a), and Hudson
tephra glasses are typically stretched-vesicle-rich and
microlite-poor (Fig. 8C). Also Hudson, located over
200 km to the southwest of Lago Shaman (Fig. 1),
had no known large eruption in the time period 1,440
to 2,090 BP when the tephras ‘a’ were deposited
(Table 1). The proximity of the core to the Melimoyu
volcano suggests that this is the most likely source
for these two chemically High Abundance type
tephra ‘a’ samples. Their ages have been estimated
as ~1,440 BP (<1,827±40 cal yrs BP) in the Lago
Shaman core and ~2,090 BP (>1,743±40 cal yrs BP)
in the Mallín El Embudo core (Table 1), and they
may possibly represent two separate events, but their
near identical appearance, thickness and chemistry
suggest they formed from the same eruption, despite
the difference in their estimated ages. Naranjo and
Stern (2004) documented a relatively large explo-
sive eruption of the Melimoyu volcano (MEL2) at
1,680±100 cal yrs BP (Table 1; Fig. 7), essentially
splitting the difference between the interpolated age
FIG. 8. Photomicrographs (2.2x2 mm) showing glass color and morphology and proportion relative to phenocrysts of:
A.
Tephra
‘a’ from Lago Shaman, containing abundant dark brown glass with only a few round vesicles and occasional plagioclase
microlites (Table 2), suggested to be derived from Melimoyu volcano (Table 1);
B.
Tephra ‘c’ from Lago Shaman, containing
clear glass with round vesicles, and abundant plagioclase and orthopyroxene phenocrysts (Table 2), suggested to be derived
from Mentolat volcano;
C.
Tephra ‘v’ from Lago Shaman, with abundant brown to tan glass containing stretched vesicles,
correlated with tephra derived from the Late-Glacial Ho eruption of the Hudson volcano (Weller
et al
., 2014); and
D.
Tephra
Cisnes 263A, with abundant dark brown glass containing only a few rounded vesicles (Table 2), suggested to be derived from
the Melimoyu volcano.
184
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
TABLE 3. TRACE-ELEMENT CONTENTS IN PARTS-PER-MILLLION (PPM) OF BULK TEPHRA SAMPLES FROM THE LAGO SHAMAN AND MALLIN EL EMBUDO
CORES AND AN OUTCROP OF GLACIAL-LACUSTRINE SEDIMENT.
Core
Shaman
Embudo
Cis-263A
Lab #
CS5054CS5055CS5056CS5057CS5058CS5059CS5060CS5061CS5062CS5063CS5064CS5065CS5066CS5051CS 3817CS5052CS5053CS 3847
tephra
a
b
c
d
e
f
g
h
i
m
q
v
y
a
b
h
j
~age
1,440
2,140
2,490
3,720
3,880
4,610
8,280
8,400
8,800
11,140
18,665
18,820
18,940
2,090
3,940
9,010
11,450
>19,000
source
Mel
Men
Men
Men
Men
Mel
Mel
Men
Men
Men
Men
Hudson
Men
Mel
Mel
Men
Men
Mel
Ti
8,813
5,632
5,281
5,863
4,992
7,298
8,202
5,669
4,378
5,380
4,964
7,366
5,723
8,647
6,911
4,252
5,041
8,569
Mn
1,036
569
1,425
1,266
1,297
965
1,054
946
905
956
850
890
773
1,065
914
1,070
1,006
1,304
Rb
34
16
12
13
11
59
55
23
21
21
20
44
20
32
56
22
17
34
Sr
508
431
457
449
440
422
429
471
377
418
381
399
449
492
398
393
430
478
Y
28
23
15
16
17
35
37
24
17
17
17
29
19
27
33
21
23
35
Zr
224
98
51
91
67
249
275
116
99
79
96
213
68
213
322
117
91
224
Nb
16
6
4
4
3
18
17
8
5
4
3
10
3
17
16
7
5
13
Cs
1.6
0.5
0.5
0.5
0.4
2.4
2.1
0.7
0.9
0.8
0.7
1.0
0.7
1.2
2.5
0.9
0.9
1.2
Ba
486
199
134
191
147
604
503
288
248
267
218
480
225
487
624
298
264
568
Hf
6.6
2.3
1.7
2.4
2.0
6.6
6.5
3.4
2.8
2.3
2.3
6.9
1.8
6.5
6.6
3.8
3.5
5.9
Pb
8.4
3.4
3.0
4.9
3.2
12.2
13.0
6.7
6.7
8.9
6.3
8.8
8.8
8.6
11.7
8.2
9.5
8.0
Th
6.8
2.6
1.2
2.0
1.8
8.0
7.6
2.9
2.6
2.1
1.7
4.6
1.7
7.1
7.7
2.4
2.8
6.1
U
1.0
0.4
0.2
0.3
0.3
1.9
1.9
0.6
1.0
0.6
0.7
1.3
0.9
0.8
2.3
0.7
0.8
1.2
La
28.4
9.76
6.16
10.1
8.37
38.8
33.8
12.8
11.1
10.5
11.9
28.0
10.9
26.5
32.8
14.7
10.6
36.1
Ce
64.7
21.3
15.5
23.4
20.9
79.8
75.8
29.6
26.2
24.0
27.8
63.2
24.8
61.0
73.0
34.1
25.5
76.2
Pr
7.99
2.62
2.18
2.91
2.37
8.81
9.33
3.76
3.30
3.90
3.57
7.61
3.08
7.68
8.05
4.53
4.38
8.50
Nd
31.9
11.7
10.4
14.2
11.8
38.5
37.2
18.8
14.1
16.3
15.4
31.1
14.1
30.3
32.8
19.7
18.6
37.1
Sm
7.11
2.65
2.82
3.39
2.95
6.91
8.13
4.34
3.36
3.43
3.53
6.49
3.38
6.44
7.01
4.78
4.31
8.21
Eu
2.02
0.93
1.19
1.15
1.19
2.24
2.29
1.46
0.90
1.10
1.06
1.79
1.18
2.01
2.03
1.58
1.44
2.69
Gd
8.07
3.20
3.21
3.86
3.56
9.02
9.50
4.93
3.93
4.25
3.80
7.37
3.82
7.66
8.12
5.82
5.19
9.49
Tb
0.97
0.43
0.41
0.48
0.52
1.18
1.18
0.62
0.48
0.55
0.46
0.88
0.47
1.01
1.02
0.77
0.85
1.23
Dy
5.84
2.55
2.98
3.14
3.37
7.85
7.10
4.59
3.12
3.72
3.16
5.24
2.96
5.54
6.53
4.53
4.64
6.47
Ho
1.09
0.45
0.58
0.64
0.66
1.25
1.37
0.69
0.53
0.58
0.53
0.94
0.55
1.08
1.16
0.95
0.90
1.26
Er
3.52
1.54
1.82
2.03
1.86
4.18
4.17
2.36
1.79
2.00
1.89
3.12
1.79
3.16
3.61
2.89
2.72
3.77
Tm
0.42
0.18
0.23
0.28
0.27
0.51
0.57
0.30
0.21
0.27
0.21
0.38
0.19
0.46
0.47
0.41
0.38
0.50
Yb
3.03
1.24
1.72
1.74
1.65
3.56
3.97
2.25
1.90
1.99
1.96
2.97
1.73
2.95
3.16
2.35
2.25
3.39
Lu
0.41
0.17
0.23
0.26
0.26
0.59
0.52
0.25
0.20
0.20
0.22
0.35
0.19
0.39
0.51
0.39
0.34
0.45
185
Stern et al. / Andean Geology 42 (2): 173-189, 2015
estimations for tephra ‘a’ in these two cores, and
we tentatively attribute both these tephra layers to
this same MEL2 eruption (de Porras
et al
., 2012).
We suggest that the different ages are due either to
near surface contamination of the samples dated or
uncertainties in the interpolated estimates.
4.2. Tephras ‘b, c, d and e’ from Lago Shaman
These tephras are all only 1 cm thick or less.
They all have chemistry similar to Very Low Abun-
dance types of rocks erupted in the southern SVZ
from the Mentolat volcano, and they all have very
similar petrographic appearance, with clear glass
shards containing rounded but not stretched vesi-
cles (Fig. 8B), and a large proportion of phenocryst
phases including plagioclase, two pyroxenes, brown
amphiboles and minor olivine. Both their chemistry
and petrography, which are essentially identical to
Mentolat derived tephra MEN1 (Naranjo and Stern,
2004), which has also been observed in cores from
near Coyhaique (Weller
et al
., 2014) and Cochrane
(Stern
et al
., 2013), are consistent with their being
derived from the Mentolat volcano. Mella
et al
.
(2012) dated tephra related to an explosive erup-
tion of Mentolat volcano between 2,615±90 and
4,340±60 cal yrs BP, and either tephra ‘d’ or ‘e’ in
the Lago Shaman core could have been produced by
this same eruption. These tephra do not appear in the
Mallín El Embudo core.
4.3. Tephra ‘b’ in Mallín El Embudo and ‘f’ in
Lago Shaman
Tephra ‘b’ in Mallín El Embudo and ‘f’ in Lago
Shaman both occur as diffuse layers mixed with
organic sediment over a zone of between 10-20 cm
thickness (Figs. 3 and 4). Both have nearly identical
chemistry similar to High Abundance type rocks
erupted from Melimoyu and Hudson volcanoes
(Fig. 6), and both consist of dark brown glass with
only a few generally round vesicles and occasional
plagioclase microlites similar to the two samples
of tephra ‘a’. Plagioclase phenocrysts are abundant
and both orthopyroxene and clinopyoxene crystals
also occur, along with minor olivine. The presence
of orthopyroxene and their high Rb, Ba, and La
contents and relatively low Sr and Ti contents
(Fig. 6) distinguishes them from Puyuhaupi basalts
(López-Escobar
et al
., 1995a). Although they were
previously attributed to the H2 eruption of the Hudson
volcano based on their chemistry (de Porras
et al
.,
2012, 2014), the lack of vesicles and the plagiocla-
se microlites in the glass distinguishes them from
typical Hudson H2 samples, and the constraints on
their age (4,600 to 4,800 cal yrs BP) suggest they
are older than the ~3,900 cal yrs BP age of the
H2 eruption (Naranjo and Stern, 1998). Therefore
we now attribute these tephra to a mid-Holocene
eruption of the Melimoyu volcano not previously
recognized in outcrop in this region.
4.4. Tephra ‘g’ from Lago Shaman
Tephra ‘g’ from Lago Shaman has petrography
(brown glass; Table 2) and High Abundance chemistry
(Fig. 6; Table 2) similar to tephra ‘a’ and ‘f’ from
this core, and we suggest the Melimoyu volcano as
its source.
4.5. Tephras ‘h’ from both cores and ‘i’ from
Lago Shaman
These tephra have Very Low Abundances
chemistry (Fig. 6) and petrography (clear glass,
abundant phenocrysts including amphibole; Table 2)
similar tephra ‘b, c, d and e’ from Lago Shaman, and
MEN1 from cores near Coyhaique and Cochrane
(Stern
et al
., 2013). They are attributed to explosive
eruptions of the Mentolat volcano. Tephra ‘i’ from
Lago Shaman and ‘h’ from Mallín El Embudo are
both similar in age and coarser grained than tephra
‘h’ from Lago Shaman, and we consider them to
be deposited from the same eruption. This eruption
may correspond to the MEN1 eruption, although the
~7,710±120 cal yrs BP age of the MEN1 eruption
(Naranjo and Stern, 2004; Stern
et al
., 2013) is so-
mewhat younger than the approximate ages (8,800
and 9,010 cal yrs BP, respectively; Table 1) of these
two tephra (Fig. 7).
4.6. Tephras ‘m’ from Shaman and ‘j’ from Mallín
El Embudo
These two tephra have similar age and Very
Low Abundance type chemistry to each other,
and are also similar petrologically (clear glass,
phenocryst-rich with amphiboles; Table 2) to other
tephra in these cores and elsewhere derived from
the Mentolat volcano.
186
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
4.7. Tephra ‘q’ from Lago Shaman
This Late-Glacial age tephra has similar Very
Low Abundance chemistry (Fig. 6) and petrography
(clear glass, abundant phenocrysts with amphibole;
Table 2) to other tephra in these cores and elsewhere
derived from the Mentolat volcano.
4.8. Tephra ‘v’ from Lago Shaman
Tephra ‘v’ from Lago Shaman occurs as a 2 cm
thick layer of brown to tan glass with abundant
stretched vesicle (Fig. 8C). The glass lacks micro-
lites and the tephra contains only rare phenocrysts
of plagioclase and orthopyroxene. The chemistry
of this tephra layer is characteristic of a High
Abundance type samples and identical to that of
Hudson Ho tephra (Weller
et al
., 2014). The age
determined in the Lago Shaman core is ~18,820 BP,
while that determined for Ho in multiple cores from
near Coyhaique is 17,340±90 cal yrs BP (Table 1;
Weller
et al
., 2014). Tephra from the Ho eruption
was distributed to the northwest of the volcano,
and the 2 cm thickness of tephra ‘v’ in the Lago
Shaman core is consistent with the isopachs of Ho
tephra estimated by Weller
et al
. (2014).
4.9. Tephra ‘y’ from Lago Shaman
This Late-Glacial age tephra has similar pe-
trography (clear glass, abundant phenocrysts with
amphiboles; Table 2) and Very Low Abundance
chemistry to other tephra in these cores and el
-
sewhere derived from the Mentolat volcano. A
Late-Glacial tephra MENo derived from Mentolat
volcano has also been described from sediment cores
taken from lakes near Coyhaique (Weller
et al
.,
2014).
4.10. Cisnes 263A
This 6 cm thick dark colored tephra contains
brown glass with a small amount of rounded vesicle
(Fig. 8D) and phenocrysts of plagioclase and two
pyroxenes. Its High Abundance type chemistry is
identical to that of tephra ‘a’ from the two cores
and its source volcano in likely to have been the
Melimoyu volcano. It is the first pre-Late-Glacial
Maximum age tephra reported in this region of the
southern Andes.
5. Discussion and Conclusions
In general, the 17 tephra from the Lago Sha-
man and Mallín El Embudo cores fall into two
easily distinguishable groups; one with abundant
brown glass with a few rounded vesicles (Fig. 8A),
a smaller proportion of plagioclase and pyroxene
phenocrysts, and High Abundance type chemistry
(Fig. 6; Table 3), and another group with clear glass
with rounded vesicles (Fig. 8B), abundant pheno-
crysts of plagioclase, pyroxenes, brown amphibole
and minor olivine, and Very Low Abundance type
chemistry (Fig. 6; Table 3). We attribute the first
group to eruptions of the Melimoyu volcano and
the second to eruptions of the Mentolat volcano.
One tephra (v) from Lago Shaman has tan to brown
glass with abundant stretched vesicles (Fig. 8C), few
phenocrysts and High Abundance chemistry (Fig. 6),
and this tephra is attributed to the large Late-Glacial
age Ho eruption of the Hudson volcano (Weller
et
al
., 2014). The glacial age tephra from the outcrop
(CIS-263A) is similar to those with brown glass
(Fig. 8D) and High Abundance chemistry (Fig. 6)
and is attributed to an eruption of the Melimoyu
volcano.
Based on their petrography, chemistry and age,
we conclude that the 17 tephra analyzed from the
Lago Shaman and Mallín El Embudo cores have
been derived from nine different eruptions of the
Mentolat volcano, three of the Melimoyu volcano,
and one from the Hudson volcano. Although, there
is still not enough spatial coverage to constrain
isopach maps for the eruptions that produced all the
tephra, some of these tephra do appear to correspond
chronologically and petrochemically to some of the
larger eruptions identified previously by Naranjo
and Stern (1998, 2004), Mella
et al
. (2012), Stern
et al
. (2013) and Weller
et al
. (2014), while others
occurred at times when no such large eruption has
been previously identified. Tephras ‘a’ in the two cores
may correspond to Late-Holocene eruption MEL2
of
Melimoyu (Table 1) previously documented by
Naranjo and Stern (2004). Either tephra ‘d’ or ‘e’
in the Lago Shaman core may have formed from
a Late-Holocene explosive eruption of Mentolat
documented by Mella
et al
. (2012). Tephra ‘b’ in
Mallín El Embudo and ‘f’ in Lago Shaman do not
result from the H2 eruption of Hudson as previously
suggested (de Porras
et al
., 2012, 2014), but rather
from a mid-Holocene eruption of the Melimoyu
187
Stern et al. / Andean Geology 42 (2): 173-189, 2015
volcano not previously described. Tephras ‘i’ from
the Lago Shaman core and ‘h’ from the Mallín El
Embudo core may have been deposited during
the mid-Holocene MEN1 eruption of Mentolat
(Table 1; Naranjo and Stern, 2004; Stern
et al
., 2013).
Tephra ‘v’ in Lago Shaman was produced by the
Late-Glacial Ho eruption of Hudson (Table 1; Weller
et al
., 2014). Tephra ‘y’ in the Lago Shaman core
may correspond to the Late-Glacial MENo eruption
of Mentolat documented in cores from lakes near
Coyhaique (Weller
et al
., 2014). The one pre-Late-
Glacial Maximum tephra Cisnes 263A also formed
from an eruption of Melimoyu volcano.
This information confirms the repeated episodic
explosive eruption of the Mentolat and Melimoyu
volcanoes beginning from, in the case of Mentolat
the earliest Late-Glacial period at approximately
>17340 cal yrs BP, and in the case of Melimoyu
before the Last Glacial Maximum at >19,670 BP.
The petrochemical data suggest that the eruptive
products of each of these two volcanoes has been
relatively constant in character over this time period,
although they differ significantly from each other
despite being located within only 70 km of each other
along strike on the volcanic front of the SSVZ arc.
The data also suggest that none of the tephra in
these cores were the products of the eruption of the
small monogenetic basaltic cones near Puyuhuapi
and Palena (Fig. 1), as these basalts have abundant
olivine and lack orthopyroxene and amphibole. The
eruption of the small monogenetic basalt cones in
the Palena and Puyuhuapi group may have been
too small to generate regional tephra falls. Nor
is there any unambiguous indication of tephra in
the upper Río Cisne valley being derived from the
Maca, Cay and/or Yanteles volcanoes, which are
Low Abundance type centers (Fig. 6). One tephra
(MAC1) observed close to Puerto Aisén has been
attributed to an explosive eruption of Maca (Naranjo
and Stern, 2004), and Mella
et al
. (2012) attribute
another tephra observed in this area to Cay volcano,
but neither of these volcanoes have summit craters/
calderas as do Hudson, Mentolat and Melimoyu, and
they may have had more effusive and less explosive
eruptive histories.
Acknowledgements
We thank FONDECYT grant #1130128 for financial
support, and the Hospital Público San Juan de Dios de La
Serena for allowing us to use their facilities to obtain the
digital X-ray images. We also thank Á. Amigo for many
constructive comments that helped improve the final paper.
References
Carel, M.; Siani, G.; Delpech, G. 2011. Tephrostratigrapy
of a deep-sea sediment sequence off the south Chilean
margin: New insight into the Hudson volcanic activity
since the last glacial period. Journal of Volcanology
and Geothermal Research 208: 99-111.
de Porras, M.E.; Maldonado, A.; Abarzúa, A.M.; Cárdenas,
M.L.; Francois, J.P.; Martel-Cea, A.; Stern, C.R.; Méndez,
C.; Reyes, O. 2012. Postglacial vegetation, fire and
climate dynamics at Central Chilean Patagonia (Lake
Shaman, 44°S). Quaternary Science Reviews 50: 71-85.
de Porras, M.E.; Maldonado, A.; Quintana, F.A.; Martel-
Cea, A.J.; Reyes, O.; Méndez, C.
2014. Environmental
and climatic changes in Central Chilean Patagonia
since the Late Glacial (Mallín El Embudo, 44
°
S).
Climate of the Past 10: 1063-1078.
D’Orazio, M.; Innocenti, F.; Manetti, P.; Tamponi, M.;
Tonarini, S.; González-Ferrán, O.; Lahsen, A.; Omarini, R.
2003. The Quaternary calc-alkaline volcanism of the
Patagonian Andes close to the Chile triple junction:
geochemistry and petrogenesis of volcanic rocks from
the Cay and Maca volcanoes (~45°S, Chile).
Journal
of South American Earth Sciences 16: 219-242.
Fontijn, K.; Lachowycz, S.M.; Rawson, H.; Pyle, D.M.;
Mather, T.A.; Naranjo, J.A.; Moreno-Roa, H. 2014.
Late Quaternary tephrostratigraphy of southern Chile
and Argentina. Quaternary Science Reviews 89: 70-84.
Futa, K.; Stern, C.R. 1988. Sr and Nd isotopic and trace
element compositions of orogenic Quaternary volcanic
centers of the southern Andes. Earth and Planetary
Science Letters 88: 253-262.
García, J.L.; Strelin, J.A.; Vega, R.M.; Hall, B.L.; Stern, C.R.
2015. Deglacial Ice-marginal glaciolacustrine envi-
ronments and structural moraine building in Torres
del Paine, south Patagonia. Andean Geology 42 (2):
190-212. doi: 10.5027/andgeoV42n2-a03.
Gutiérrez, F.; Gioncada, A.; González-Ferrán, O.; Lahsen, A.;
Mazzuoli, R. 2005. The Hudson volcano and sur
-
rounding monogenetic centres (Chilean Patagonia):
an example of volcanism associated with ridge-trench
collision environment. Journal of Volcanology and
Geothermal Research 145: 207-233.
Hickey, R.L.; Frey, F.A.; Gerlach, D.C. 1986. Multiple
sources for basaltic arc rocks from the Southern Vol-
canic Zone of the Andes (34-41°S): Trace element and
isotopic evidence for contributions from subducted
188
T
EPHROCHRONOLOGY
OF
THE
UPPER
R
ÍO
C
ISNES
VALLEY
(44°S),
SOUTHERN
C
HILE
oceanic crust, mantle, and continental crust. Journal
of Geophysical Research 91: 5963-5983.
Hickey-Vargas, R.L.; Moreno-Roa, H.; López-Escobar, L.;
Frey, F.A. 1989. Geochemical variations in Andean
basaltic and silicic lavas from the Villarrica-Lanín
volcanic chain (39.5°S): an evaluation of source
heterogeneity, fractional crystallization and crustal
assimilation. Contributions to Mineralogy and Petro-
logy 103: 361-386.
Hickey-Vargas, R.L.; Sun, M.; López-Escobar, L.;
Moreno-Roa, H.; Reagan, M.K.; Morris, J.D.; Ryan
J.G. 2003. Multiple subduction components in the
mantle wedge: evidence from eruptive centers in
the Central Southern volcanic zone, Chile. Geology
30 (3): 199-202.
Kratzmann, D.J.; Carey, S.; Scasso, R.A.; Naranjo, J.A.
2009. Compositional variations and magma mixing in
the 1991 eruptions of Hudson volcano, Chile. Bulletin
of Volcanology 71 (4): 419-439.
Kratzmann, D.J.; Carey, S.; Scasso, R.A.; Naranjo, J.A.
2010. Role of cryptic amphibole crystallization in
magma differentiation at Hudson volcano, Southern
Volcanic Zone, Chile. Contributions to Mineralogy
and Petrtology 159: 237-264.
López-Escobar, L.; Kilian, R.; Kempton, P.; Tagiri, M.
l993. Petrology and geochemistry of Quaternary rocks
from the southern volcanic zone of the Andes between
41°30’ and 46°00’S, Chile. Revista Geológica de
Chile 20 (1): 33-55. doi: 10.5027/andgeoV20n1-a04.
López-Escobar, L.; Cembrano, J.; Moreno, H. 1995a.
Geochemistry and tectonics of the chilean Southern
Andes basaltic Quaternary volcanism (37º-46ºS).
Revista Geológica de Chile 22 (2): 219-234. doi:
10.5027/andgeoV22n2-a06.
López-Escobar, L.; Parada, M.A.; Hickey-Vargas, R.; Frey,
F.A.; Kempton, P.D.; Moreno, H. 1995b. Calbuco
Volcano and minor eruptive centres distributed along
the Liquiñe-Ofqui Fault Zone, Chile (41°-42°S):
contrasting origin of andesitic and basaltic magma
in the Southern Volcanic Zone of the Andes. Contri-
butions to Mineralogy and Petrology 119: 345-361.
Lowe, D.J. 2011. Tephrochronology and its application:
a review. Quaternary Geochronology 6: 107-153.
Mella, M.; Ramos, A.; Kraus, S.; Duhart, P. 2012. Datos
tefroestratigráficos de erupciones Holocenas del Volcán
Mentolat, Andes del Sur (44°40’S), Chile.
In
Congreso
Geológico Chileno, No. 13, Actas, Antofagasta.
Méndez, C.; Reyes, O. 2008. Late Holocene human occu-
pation of Patagonian forests: a case of study at Cisnes
River basin (44°S, Chile). Antiquity 317: 560-570.
Méndez, C.; Reyes, O.; Maldonado, A.; Francois, J.P. 2009.
Ser humano y medio ambiente durante la transición
Pleistoceno Holoceno en las cabeceras del río Cisnes
(44°S, Aisén Norte).
In
Arqueología de Patagonia:
una mirada desde el último confín (Salemme, M.;
Santiago, F.; Álvarez, M.; Piana, E.; Vázquez, M.;
Mansur, E.; editors). Editorial Utopías: 75-83. Ushuaia.
Naranjo, J.A.; Stern, C.R. 1998. Holocene explosive
activity of Hudson Volcano, southern Andes. Bulletin
of Volcanology 59: 291-306.
Naranjo, J.A.; Stern, C.R. 2004. Holocene tephrochrono-
logy of the southernmost part (42-45°S) of the Andean
Southern Volcanic Zone. Revista Geológica de Chile
31 (2): 225-240. doi: 10.5027/andgeoV31n2-a03.
Peccerillo, A.; Taylor, S.R. 1976. Geochemistry of
Eocene
calc-alkaline volcanic rocks from Kastamonu area,
Northern Turkey. Contributions to Mineralogy and
Petrolology 58: 39-63.
Prieto, A.; Stern, C.R.; Esterves, J. 2013. The peopling
of the Fuego-Patagonian fjords by littoral hunter-
gatherers after the mid-Holocene H1 eruption of
Hudson volcano. Quaternary International 317: 3-13.
Reyes, O.; Méndez, C.; Maldonado, A.; Velásquez, H.;
Trejo, V.; Cárdenas, M.; Abarzúa, A.M.; 2009. Uso
del espacio de cazadores recolectores y paleoambiente
Holoceno en el valle del Río Cisnes, región de Aisén,
Chile. Magallania 37: 91-107.
Saadat, S.; Stern, C.R. 2011. Petrochemistry and genesis
of olivine basalts from small monogenetic parasitic
cones of Bazman stratovolcano, Makran arc, south-
eastern Iran. Lithos 125: 609-617.
Sellés, D.; Rodríguez, A.C.; Dungan, M.A.; Naranjo, J.A.;
Gardeweg, M. 2004. Geochemistry of Nevados de
Longaví volcano (36.2°S): a compositionally atypi-
cal arc volcano in the Southern Volcanic Zone of the
Andes. Revista Geológica de Chile 31 (2): 293-315.
doi: 10.5027/andgeoV31n2-a08.
Stern, C.R. 2004. Active Andean Volcanism: its geologic
and tectonic setting. Revista Geológica de Chile 31 (2):
161-206. doi: 10.5027/andgeoV31n2-a01.
Stern, C.R.; Skewes, M.A.; Duran, M. 1976. Volcanismo
orogénico en Chile austral.
In
Congreso Geológico
Chileno, No. 1, Actas 2: 195-212. Santiago.
Stern, C.R.; Moreno, H.; López-Escobar, L.; Clavero, J.E.;
Lara, L.E.; Naranjo, J.A.; Parada, M.A.; Skewes, M.A.
2007.
In
The Geology of Chile (Moreno, T.; Gib-
bons, W.; editors). Geologic Society of London:
149-180. Bath.
Stern, C.R.; Moreno, P.I.; Henrique, W.I.; Villa-Martínez, R.P.;
Sagredo, E.; Aravena, J.C. 2013. Tephrochronology in
189
Stern et al. / Andean Geology 42 (2): 173-189, 2015
the area around Cochrane, southern Chile.
Bollettino
di Geofisica 54, Supplement 2: 199-202.
Stuiver, M.; Reimer, P.J.; Braziunas, T.F. 1998. High-
precision radiocarbon age calibration for terrestrial
and marine samples. Radiocarbon 40 (3): 1127-1151.
Vargas, G.; Rebolledo, S.; Sepúlveda, S.A.; Lahsen, A.; Thie-
le, R.; Townley, B.; Padilla, C.; Rauld, R.; Herrera, M.J.;
Lara, M. 2013. Submarine earthquake rupture, active
faulting and volcanism along the major Liquiñe-Ofque
Fault Zone and implications for seismic hazard as-
sessment in the Patagonian Andes. Andean Geology
40 (1): 141-171. doi: 10.5027/andgeoV40n1-a07.
Völker, D.; Kutterolf, S.; Wehrmann, H. 2012. Compara-
tive mass balance of volcanic edifices at the southern
volcanic zone of the Andes between 33°S and 46°S.
Journal of Volcanology and Geothermal Research
205: 114-129.
Watt, S.F.L.; Pyle, D.M.; Mather, T.A. 2011. Geology,
petrology and geochemistry of the dome complex
of Huequi volcano, southern Chile. Andean Geology
38 (2): 335-348. doi: 10.5027/andgeoV38n2-a05.
Watt, S.F.L.; Pyle, D.M.; Mather, T.A.; Naranjo, J.A.
2013. Arc magma compositions controlled by linked
thermal and chemical gradients above the subduct-
ing slab. Geophysical Research Letters 40 (11):
2550-2556.
Weller, D.; Miranda, C.G.; Moreno, P.I.; Villa-Martínez, R.;
Stern, C.R. 2014. A very large (>20 km
3
) late-glacial
eruption (Ho) of the Hudson volcano, southern Chile.
Bulletin of Volcanology 76: 831-849.
Manuscript received: October 03, 2014; revised/accepted: May 11, 2015; available online: May 11, 2015.
logo_pie_uaemex.mx