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Possible Late Pleistocene volcanic activity on
Nightingale Island, South Atlantic Ocean, based on
geoelectrical resistivity measurements, sediment
corings and 14C dating
Anders Anker Bjørk a , Svante Björck b , Anders Cronholm b , James Haile a c , Karl Ljung b &
Charles Porter d
a Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen,
Øster Voldgade 5-7, 1350, Copenhagen K, Denmark
b Division of Geology, Department of Earth and Ecosystem Sciences, Lund University,
Sölvegatan 12, 22362, Lund, Sweden
c School of Biological Sciences, Murdoch University, Perth, Western Australia
d Patagonian Research Foundation, Puerto Williams, Chile
Available online: 11 Oct 2011
To cite this article: Anders Anker Bjørk, Svante Björck, Anders Cronholm, James Haile, Karl Ljung & Charles Porter (2011):
Possible Late Pleistocene volcanic activity on Nightingale Island, South Atlantic Ocean, based on geoelectrical resistivity
measurements, sediment corings and 14C dating, GFF, 133:3-4, 141-147
To link to this article: http://dx.doi.org/10.1080/11035897.2011.618275
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Possible Late Pleistocene volcanic activity on Nightingale Island,
South Atlantic Ocean, based on geoelectrical resistivity measurements,
sediment corings and
14
C dating
ANDERS ANKER BJØRK
1
, SVANTE BJO
¨RCK
2
, ANDERS CRONHOLM
2
, JAMES HAILE
1,3
,
KARL LJUNG
2
and CHARLES PORTER
4
Bjørk, A.A., Bjo
¨rck, S., Cronholm, A., Haile, J., Ljung, K. & Porter, C., 2011: Possible Late Pleistocene volcanic activity
on Nightingale Island, South Atlantic Ocean, based on geoelectrical resistivity measurements, sediment corings and
14
C
dating. GFF, Vol. 133 (Pt. 3–4, September–December), pp. 141–147. Stockholm. ISSN 1103-5897.
Abstract: Tristan da Cunha is a volcanic island group situated in the central South Atlantic. The oldest of
these islands, Nightingale Island, has an age of about 18Ma. In the interior of the island, there are several
wetlandssituated in topographic depressions. The ages of these basins have been unknown, and their genesis
has been debated. Aiming towards the reconstruction of the geomorphological history of these basins, we
conducted geoelectrical resistivity measurements to map the subsurface topography, extracted peat and
sediment cores and dated the onset of sedimentation applying the radiocarbon method. The irregular shapes
of the basins and the lack of clear erosional features indicate that they are not eruption craters and were not
formed by erosion. Instead, we regard them as morphological depressions formed between ridges of
trachytic lava flows and domes at a late stage of the formation of the volcanic edifice. The onset of
sedimentation within these basins appears to have occurred between 24 and 37 ka with the highest situated
wetland yielding the highest ages. These ages are very young compared to the timing of the main phase of
the formation of the island, implying volcanic activity on the island during the Late Pleistocene.
Keywords: South Atlantic; Nightingale Island; peat bogs; subsurface topography;
14
C dating; young
volcanism.
1
Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade
5-7, 1350 Copenhagen K, Denmark
2
Division of Geology, Department of Earth and Ecosystem Sciences, Lund University, So
¨lvegatan 12, 22362
Lund, Sweden; svante.bjorck@geol.lu.se
3
School of Biological Sciences, Murdoch University, Perth, Western Australia
4
Patagonian Research Foundation, Puerto Williams, Chile
Manuscript received 18 April 2011. Revised manuscript accepted 15 August 2011.
Introduction
The Tristan da Cunha island group is situated in the central South
Atlantic and consists of three main islands, Tristan da Cunha,
Inaccessible Island and Nightingale Island (NI), and a few
smaller islands and islets (Fig. 1). While Tristan da Cunha is the
largest (c. 100 km
2
) of the three main islands, NI is the smallest
(c. 3 km
2
) and is situated 35 km SSW of Tristan da Cunha.
The islands are of volcanic origin and their mid-ocean ridge
basalts belong to the so-called DUPAL anomaly, which is a belt
of basalts stretching from 408S in the South Atlantic to eastwards
into the Pacific (Dupre
´& Alle
`gre 1983; Hart 1984), and have
been assigned both shallow continental and deep cycled sources.
The DUPAL signature is defined by Pb isotopes, and the
South Atlantic mantle plumes have a very characteristic isotope
signature and most likely have a common formation history and
a deep source possibly with some additional lithosphere material
from plume erosion (Class & le Roex 2011).
Tristan da Cunha is still a volcanically active intraplate
volcano with its latest eruption in 1961. This was a strombolian
eruption producing both scoria cones and gas-poor lava flows of
trachyandesitic composition (Chevallier & Verwoerd 1987),
close to the settlement of the island. Earth quakes, usually off-
shore, are sometimes felt on the island. NI is the oldest of the
three main islands with a highest reported K – Ar date of
18 ^4 Ma (McDougall & Ollier 1982). The more deeply eroded
features of NI, compared with those of the two other islands,
have also been regarded as an indication that it is the oldest
island in the group. The submarine part of NI is of about the
same size as that of Tristan da Cunha, and it is likely that its sub-
aerial part was once as big as Tristan da Cunha is today.
During a coring campaign in lakes and peat lands on Tristan
da Cunha in 2003, it proved difficult to find crater-lake
sediments older than c. 2500 years (Ljung et al. 2006), and the
sediments are rich in tephra layers, implying continuous ash
fall-outs in the late Holocene. On NI, considerably older
sediments, extending back to 10,700 cal yr BP, were retrieved
from a small overgrown pond (Ljung & Bjo
¨rck 2007), but they
GFF
volume 133 (2011), pp. 141–147. Article
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only contained one possible tephra layer. The dominating
strong westerlies transport any Tristan particles eastwards and
not towards NI.
The strategic position of the islands in the central South Atlantic
(Fig. 1A) and at the northern rim of the Southern Hemisphere
Westerlies (SHW) make them a perfect target for studies of
paleoclimatic inter-hemispheric connections (Ljung & Bjo
¨rck
2007; Ljung et al. 2008) and latitudinal changes of the SHW.
During fieldwork in 2010, coring efforts were focused on NI with
the aim to retrieve Late Pleistocene sediments for paleoclimatic
studies of the Last Termination. Cores were extracted from three
of the four wetlands situated in small enclosed basins in the
central part of NI, locally known as the Molly Ponds (Fig. 1C) and
named 1
st
,2
nd
,3
rd
and 4
th
Pond by the Tristan islanders. With the
exception of 3
rd
Pond, these basins are totally overgrown and can
be characterized as sedge dominated fens. 3
rd
Pond contains a
small area of open water, but is otherwise also peat covered. There
is no surface drainage between the basins; they are completely
separated by lava (trachyte) ridges. However, the porosity of the
upper part of the ridges allows the possibility of subsurface
drainage between the basins.
The objective of this subproject was to use geoelectrical
resistivity measurements and corings to map the subsurface
topography of the basins and to date the onset of sedimentation
with radiocarbon. Since much of the basin topography is hidden
underneath the peat surface of the wetlands and the age of the
surrounding bedrock is unknown, previous studies of
the history of the landscape have been limited. Mapping of the
bottom topography and dating of the sediments filling the basins
may allow us to draw conclusions about their age and evolution.
Nightingale Island
Two main bedrock lithologies are recognized on NI, porphyritic
trachytes and pyroclastic ashes and agglomerates (Baker et al.
1964). The older pyroclastic unit consists of yellow volcanic
agglomerates, cut by basic dykes. Above this follows an often
structureless unit of intrusive trachytes, making up the western
part of the island, where the Molly Ponds are situated, as well as
the high ridge in the northeast (Fig. 1C). In places along the
coast, this trachyte unit is overlain by a trachytic pebble/boulder
horizon interpreted as a period of volcanic quiescence and
(wave) erosion (Baker et al. 1964). The youngest unit is complex
and is best displayed on the south coast at Sea Hen Rocks, where
the raised beach deposits are overlain by 3 m of fine tuff, rich in
plant remains, and followed by 5.5 m of trachytic lava, possibly
issued from a mainly pyroclastic parasitic centre (Baker et al.
1964). This complex sequence ends with 7 – 8 m of bedded ash
and agglomerates. These geological units reflect at least four
major stages of evolution: a first explosive phase generating
pyroclastic rocks, followed by an effusive phase which produced
the trachytic lava flows, a calm and erosive phase, and finally a
complex phase of explosive activity and lavas forming the
youngest sequence. Baker et al. (1964) also speculate that a
cinder cone remnant, 400 m west of Sea Hen Rocks, was the
source of material for the younger pyroclastic unit. Furthermore,
on the northeast coast of the island, at the Huts and southwards,
Fig. 1.(A) Maps of the location of the Tristan da Cunha island group in the South Atlantic, (B) the position of the three main islands and (C) NI and
surrounding islets with a generalized geological map. Bedrock and geological features are mainly based on Baker et al. (1964).
142 Bjørk et al.: Possible Late Pleistocene volcanic activity on Nightingale Island GFF 133 (2011)
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the youngest tephra seems to have been followed by a period of
wave erosion (Baker et al. 1964). However, it is not clear how
this raised beach could be differentiated from the older beach.
It is noteworthy that the plant material in the fine tuff at Sea
Hen Rocks was
14
C dated to 39,160 (þ6090, 23410)
14
C years
BP (Baker et al. 1964). Considering that this dated tephra is
overlain by trachytic lava, it implies young volcanic activity.
Furthermore, Ollier (1984) notes that peat from Ned’s Cave, just
inside Sea Hen Rocks, has been dated to .37,000
14
C years BP,
and at a coastal section at Peat Cave in the very north,
Ollier (1984) radiocarbon dated peat and K–Ar dated a trachyte
that cuts into the peat and tuff deposits. While the
14
C age was
infinite, the K–Ar dating of the trachyte gave an age of
370,000 ^80,000 years, which is another indication of young
volcanic activity on the island. Based on the general volcanic
stratigraphy, Ollier (1984) also noted that it is very likely that a
fairly large part of the island, including the Molly Ponds area,
postdates the Peat Cave peat. He also notes the unfortunate fact
that the bedrock around the Molly Ponds, because of its porous
character, is unsuitable for dating, which we also concluded
during the 2010 field campaign. In this context, we also find it
worthwhile mentioning that Maund et al. (1988) report
unpublished dates of 0.4– 0.15 Ma lavas on NI, but without
any details of where the ages originate from. It is thus possible
that in spite of the high age of the oldest rocks of the island, the
volcanic activity has influenced the island throughout the
Pleistocene. This may also have been the case for Inaccessible
Island (Chevallier et al. 1992).
The Molly Ponds
The circular shape of the ponds on NI was originally interpreted
as reflecting remnants of old individual craters (Douglas 1930).
However, based on the absence of explosion products in the
vicinity of the basins and the fact that they are more irregular
than circular in their shape, it has also been suggested that they
are some type of erosional features (Baker et al. 1964).
Furthermore, Ollier (1984) notes the absence of a drainage
pattern in the Pond area and believes that the enigmatic
topography can be explained by “eruption of trachyte domes that
occasionally exploded into irregular heaps of boulders” (Fig. 2).
If the Molly Ponds are craters from the time when the main
island body formed, they should have been filled in by sediments
a long time ago and the surface or soil of the ponds should be of
pre-Quaternary age. This is obviously not the case. On the other
hand, if the ponds are created by young volcanic activity, i.e. of
Late Pleistocene age, it would indicate that at least parts of the
island are young.
Fig. 2. Photo taken from the so-called “heap of boulders”, southwest of the 3
rd
Pond, towards the northeast. The size of the boulders can be related to
the people in the centre of the picture. The lava ridge west of 3
rd
Pond (see Fig. 4) is seen behind the people. The green flat area to the right is the
central and overgrown part of 3
rd
Pond. The ridge between 3
rd
and 2
nd
Ponds (Fig. 4) is distinguished behind the left part of the green area. To the
very right the lower part of the hill between 1
st
and 3
rd
Ponds is seen, displayed as a grey massive in Fig. 4. The fairly wide peak in the distance in
the middle of the photo is the ridge north-northwest of 2
nd
Pond (Fig. 4; photo by K. Ljung).
GFF 133 (2011) Bjørk et al.: Possible Late Pleistocene volcanic activity on Nightingale Island 143
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Methods
The depths of 2
nd
and 3
rd
Ponds from the surface to the bedrock
have been established by applying geoelectrical resistivity
techniques and a Russian peat sampler. Corings were also carried
out in 1
st
Pond, but the restricted time available on the island did not
allow for the time-consuming resistivity measurements in the two
other ponds.The hard and the compact sediments in the basins have
limited the use of corer and probes to measure the sediment
thickness in many areas: therefore, geoelectrical measurements
were conducted. The ages of the bottommost sampled sediments
have been established using radiocarbon dating.
The geoelectrical resistivity method consists in determining
the earth’s specific electrical resistance (
r
), measured in ohms
(V) in a vertical profile. Since the volcanic bedrock, forming the
base of the basins, has a higher electrical resistance than the
filling of peat and gyttja, the interface between bedrock and
gyttja is reflected by an increase in specific electrical resistance.
The Schlumberger electrode configuration was used for
vertical electric soundings. In the Schlumberger array, the
position for the potential electrodes is kept constant, while the
current electrodes are moved further away from the measuring
point. Measurements were carried out by applying a current
electrode spacing of up to 130 m and a potential electrode
spacing of 1–2 m. The program RESID was used for modelling
(Loke 2001) and is freely available from the Geotomo Software
(http://www.geoelectrical.com/downloads.php).
A surface representation of the calibrated depth data has been
generated using a triangulated irregular network (TIN) model.
The TIN model is generated by linear interpolation, which is
considered conservative. However, it represents the best model
estimate in cases where the bottom topography is unknown.
The radiocarbon age data were obtained from bulk sediment
samples due to absence of macrofossils in the deeper part of the
sediments. However, Ljung & Bjo
¨rck (2007) showed that
14
C
measurements of bulk sediment and macrofossils from the same
levels in 2
nd
Pond resulted in similar ages, implying that
14
C
ages of bulk sediments are fairly reliable in this environment.
The ages were calibrated using the IntCal09 data set with a
delta-R of 56 ^20 years to compensate for the apparently older
age of
14
CO
2
in the Southern Hemisphere (Reimer et al. 2004).
Results
1
st
Pond
This wetland is situated at an altitude of 207 m a.s.l., which is
the highest located of the four Molly Ponds (Figs. 1C, 3).
The experience of sound at the sudden stop of the coring at
9.37 m was interpreted as the bedrock base of the basin, and the
age of the bottommost core was established by two radiocarbon
dates (Table 1). The sample at 9.33 cm was dated to c. 36,500 cal
yr BP and at 8.55 m to c. 34,500 cal yr BP. By extrapolating to
the bottom of the core, sedimentation at 1
st
Pond could have
begun at c. 37,000 cal yr BP.
No resistivity measurements were made of the basin, and thus
we cannot rule out the existence of deeper parts of the basin with
potentially older sediments.
Table 1. The oldest radiocarbon dates from 1
st
,2
nd
and 3
rd
Ponds.
Site name Sample
Depth
(cm)
14
C age BP
(1
s
)
Calibrated age BP
(2
s
)
1
st
Pond LuS 9140 933 32010 (^300) 37308– 35430
LuS 9141 855 29870 (^250) 34997– 33801
2
nd
Pond LuS 9062 1282 13935 (^85) 17438– 16772
LuS 9063 1137 11995 (^80) 14050–13650
3
rd
Pond LuS 9156 682 13830 (^75) 17088– 16676
LuS 9157 590 11190 (^70) 13219– 12794
Notes: Dates are calibrated using IntCal09 and OxCal online (https://c14.arch.ox.ac.u-
k/oxcal/OxCal.html) with a constant correction factor of 56 ^20 years to account for the
apparently older
14
C age of the Southern Hemisphere atmospheric CO
2
.
Fig. 3. Schematic illustration of the location of the basins and main core sites, including the general lithostratigraphy of the cores, the calibrated ages
of the lowermost radiocarbon-dated sediments and the extrapolated bottom ages. The vertical axis shows the altitude above sea level. The altitudes
of the wetland surfaces and ridges separating the basins were measured in the field using multiple GPS readings calibrated to sea level.
The horizontal axis is based on the Google Earth map distances between the three main coring points at the three sites (Fig. 4), shown as black
triangles. The outlines of the basins (stippled) are only approximate.
144 Bjørk et al.: Possible Late Pleistocene volcanic activity on Nightingale Island GFF 133 (2011)
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2
nd
Pond
Figure 4 shows the bathymetry model based on resistivity
measurements, corings and probings at 2
nd
Pond, situated at
200 m a.s.l. Based on resistivity measurements, the maximum
depth was determined to 15.5 m in the centre of the basin. The
shape of the central basin is elliptic with depths of 5 –15 m and
follows the outline of the present day wetland, and with the most
striking feature being the pronounced northeast – southwest
trending trough (Fig. 4). The trough has a slightly shallower part
in the middle separating two sub-basins. The threshold
separating the two sub-basins is also reflected in the topography
of the bedrock around the basin. Both the south-western and
north-eastern parts of the basin are very shallow. Measurements
close to the edge of the pond reveal steep bottom topography
similar to that above ground (Fig. 2).
In the central part of the basin, marked with a green triangle in
Fig. 4, we managed to push the Russian sampler down to
11.75 m, and with a screw-corer, attached to the Russian rods, we
were able to penetrate down to c. 13.7 m. The deepest sediments
retrieved with the screw-corer originate from a depth of 12.82 m
and have been dated to c. 17,000 cal yr BP (Table 1). Combining
a series of new
14
C dates from the lowest parts of the recovered
cores with an age model anchored to the Ljung & Bjo
¨rck (2007)
data, we are able to extrapolate likely sedimentation rates and
Fig. 4. Map of the Ponds plateau, showing the depth model from 2
nd
Pond, coring sites (black triangles for main coring sites) and the position of the
profile line from 3
rd
Pond (Fig. 5). The approximate positions of the most distinct lava flows and ridges, which have defined the formation and
position of the ponds, are marked with light grey-shaded rectangles.
GFF 133 (2011) Bjørk et al.: Possible Late Pleistocene volcanic activity on Nightingale Island 145
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thereby to roughly estimate the age of the modelled maximum
depth of 15.5 m to 24,000–33,000 cal yr BP.
3
rd
Pond
Geoelectrical resistivity measurements at 3
rd
Pond were focused
on the northern half of the basin where sediment cores were
retrieved. Due to lack of time, the southern part of the basin was
not fully mapped; hence, the complete bathymetry could not be
modelled. The basin is subdivided into two sub-basins with a
threshold in the middle, which is also reflected in the topography
surrounding the pond (Fig. 5). A 20-m stack of large trachyte
boulders is located south of the pond (Fig. 2). The sides of the
basin are steep and a maximum depth of 10 m is reached at just
20 m distance from the shore. The corings, a short distance east of
the open water, reached a depth of almost 7 m in very consolidated
sediments. The oldest
14
C age data from the cores in this part of the
wetland yielded ages of c. 13,000 cal yr BP (5.90 m) and almost
17,000 cal yr BP (6.82 m). Tentative extrapolation of these ages
implies that the sedimentation in 3
rd
Pond (at c. 10 m) could have
started as early as 27,000 – 32,000 cal yr BP.
Discussion
Unfortunately, the bedrock surrounding the Molly Ponds is
unsuitable for Ar– Ar dating, which forced us to establish their
origin and age by other means. The complex volcanic history of
the island, previously studied by Baker et al. (1964), Ollier
(1984) and Maund et al. (1988), suggests that its development is
a result of several eruptive cycles after the first build-up of the
island body. We think that the genesis of the Molly Ponds must
be related to a recent volcanic period. If the Molly Ponds are
remnants of old craters, associated with the main part of the
island, then the sediments filling the craters should be of pre-
Quaternary, or at least early-mid Quaternary age. This is,
however, contradicted by the Marine Isotope Stage 3 (MIS 3)
ages of the bottom sediments.
The lack of pyroclastic rocks in the vicinity of the ponds
convinced Baker et al. (1964) to discard the option of interpreting
them as craters. Instead, he suggested that they may be of
erosional origin. Based on the general morphology and our
subsurface mapping in two of the ponds we do not, however, find
any evidence for this, because there is no common drainage
system/pattern that could have channelled water through and out
of the pond area. On the contrary, the Molly Pond area consists of
very pronounced and restricted basins, making it highly unlikely
that they could be of erosional origin. This was also partly noted
by Ollier (1984), although he had to rely exclusively on the
surface morphology, and he noted that eruptive processes are the
most plausible genesis behind the topography.
From the subsurface topography and radiocarbon dates, we can
infer age estimates for the onset of sedimentation in the basins. It
is reasonable to assume that the accumulation of sediments
Fig. 5. Depth profile from the northern part of 3
rd
Pond, showing the bedrock depression from where the deepest core was extracted and the
threshold dividing the pond’s northern and southern halves. The position of the profile is plotted on the map in Fig. 4.
146 Bjørk et al.: Possible Late Pleistocene volcanic activity on Nightingale Island GFF 133 (2011)
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started shortly after the basins were formed, and radiocarbon ages
of the bottom sediments can therefore provide an approximate
(minimum) age of the basins. In 1
st
Pond, accumulation of
sediments began no later than 37,000 cal yr BP. This age is in the
same order of magnitude as the
14
C dated plant remains in the
volcanic ashes at Sea Hen Rocks, dated to 39,160 (þ6090,
23410)
14
C yr BP (Baker et al. 1964), overlain by a trachytic
lava. Although the calibration of such high
14
C ages is very
uncertain, the age of this tephra is certainly older than 40,000 cal
yr BP, and with a maximum calibrated age around 45,000 cal yr
BP. This is probably at least some thousands of years older than
the oldest sediments in 1
st
Pond. It is therefore plausible to
suspect that such young eruptions could have been the main agent
behind the formation of the Molly Ponds.
Our hypothesis is that an eruptive phase during MIS 3 produced
trachyte domes, lava flows, and perhaps also heaps of boulders,
which resulted in creating a landscape of ridges and domes of lava
with basins in between. After the eruptions ceased and the lava
flows cooled down, low-lying areas between the lava ridges were
slowly filled up with fine-grained material from weathering
processes, such as clay minerals, derived from the surrounding
volcanic material, as well as from organic material. We speculate
that, at first, water may have percolated through the fairly coarse
lava material, but the infilling of fine mineral and organic matter
finally led to a sealing off of the basins. 1
st
Pond, which is the
highest situated basin, has by far the largest local catchment,
possibly sealed off first around 37,000 cal yr BP. The lower lying
2
nd
and 3
rd
Ponds may have been sealed later, perhaps because it
took longer time for these ponds to be sealed off with fine-grained
material. It is also possible that later eruptions changed the
topography and hydrology of the landscape. The irregularly
shaped heap of large boulders south-west of 3
rd
Pond, with very
little or no vegetation cover (Fig. 2), is seen as a light area south-
west of the southern end of 3
rd
Pond in the very low left corner of
Fig. 4. This feature has a fresher and younger appearance than the
other trachyte ridges in the Molly Ponds area, and might represent
the last of a series of eruptions. It is situated in the direction of
drainage from 3
rd
Pond towards the south shore of the island.
Since this feature is in the drainage path from 3
rd
Pond, it might
have influenced the hydrology, and by e.g. up-damming caused
changes in the local groundwater level. This could also have
influenced the onset of sedimentation in the respective basins, and
be at least in part, an explanation for the older ages in the bottom
of the highest situated basin.
Conclusions
By mapping the subsurface topography and dating the
bottommost sediments of small enclosed basins on NI, we
have arrived at a possible explanation for the geomorphology
and formation of the basins. Radiocarbon dates of the
bottommost retrieved sediments and depth readings from
geoelectrical resistivity measurements indicate that sedimen-
tation in the basins started between 24,000 and 37,000 cal yr BP.
The highest situated basin, 1
st
Pond, also has the oldest bottom
age, around 37,000 cal yr BP. The two basins situated at lower
altitudes yielded younger ages, 24,000 – 33,000 cal yr BP.
The shape of the basins and the topography separating them
indicate that they were formed in-between ridges and domes of
lava. Fresh and young looking lava and heaps of boulders at the
south-western end of 3
rd
Pond probably were generated
during the most recent eruption. This eruption may also have
affected the hydrologic situation by partly filling and damming
the southern part of 3
rd
Pond. This could be part of the
explanation of the younger onset of sedimentation in the lower
lying basins.
Our results show that parts of the geomorphology of this old
and eroded island, compared, e.g., with the morphology of
Tristan da Cunha island, might very well be of Late Pleistocene
age, which is much younger than previously thought. This
implies fairly recent volcanic activity and as a consequence
profound effects on the landscape, which created much of the
present topography, including the small basins. The fairly young
basins featuring continuous sediment accumulation represent an
excellent opportunity for proxy-based studies on the environ-
mental and climatic history in the South Atlantic reaching back
to MIS 3. Targeting this issue is the next step of the project.
Acknowledgements.–This study was financed by the Swedish Research Council (VR) to
the project “The Last Termination in the central South Atlantic” granted to SB. Parts of the
logistics were financed by a grant to SB from the Crafoord Foundation. We are very thankful
for this support. We would also like to acknowledge fieldwork assistance from Martin
Bjo
¨rck (Uppsala), the logistic support from the Tristan islanders and especially the help from
Warren Glass and Donny Green during our stay on the island. We also appreciate the very
detailed comments from one of the reviewers, whose obvious interest in the topic increased
the quality of the manuscript.
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