Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127 – 148
www.elsevier.com/locate/palaeo
An environmental reconstruction of the sediment infill of the
Bogotá basin (Colombia) during the last 3 million years
from abiotic and biotic proxies
Vladimir Torres a,*, Jef Vandenberghe b, Henry Hooghiemstra a
a
Institute for Biodiversity and Ecosystem Dynamics (IBED), Faculty of Science, University of Amsterdam, Kruislaan 318,
1098 SM Amsterdam, The Netherlands
b
Faculty of Earth Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
Received 21 October 2004; received in revised form 6 May 2005; accepted 10 May 2005
Abstract
The lacustrine sediments of the intramontane basin of Bogotá (48N, 2550 m altitude) were collected in a 586-m deep core
Funza-2. Absolute datings show sediment infill started c. 3.2 Ma and continued almost without interruptions as a result of the
balance between tectonic subsidence and sediment infill. Analysis of downcore changes in lithology, grain size, facies, loss on
ignition (LOI), and hydrosere vegetation at 20-cm intervals along the core produced a 2200-sample record of basin dynamics and
lake level changes with a temporal resolution from c. 800 years (during the last 1.5 Ma) to c. 2000 years (from 1.5 to 3.2 Ma). We
recognized 11 discrete sedimentary facies that reflect 4 different depositional environments. Facies 1 and 2 correspond to
lacustrine environment where the LOI is b 20%. A swamp environment is reflected by facies 11, where the LOI is N20%. A
fluvio-lacustrine environment is represented by the facies 3, 4, 5, 7 and 9. A fluvial environment is reflected by facies 6, 8 and 10.
Basin infill started with accumulation in a fluvio-lacustrine environment between 586 and 530 m below the present-day
sediment surface of the basin. In the 530- to 325-m interval (c. 3–1.5 Ma), the basin contained mainly shallow water and
swamps, in combination with some fluvial activity. The 325–5-m interval (1.5–0.028 Ma) shows almost uninterrupted lacustrine
paleoenvironmental conditions. The uppermost 5 m reflect a fluvial paleoenvironment deposited by the Bogotá River and its
tributaries. The downcore changing ratio between shallow water aquatics (Myriophyllum, Ludwigia, Polygonum, Cyperaceae)
and aquatics of deeper water (Isoëtes) is indicative of lake level changes. Isoëtes as an indicator of high water levels is not
consistent with fluvial and fluvio-lacustrine depositional regimes. Several lithological discontinuities, evidenced by the sharp
transition from swamp deposits to fluvio-lacustrine and fluvial deposits, are present in the core, in the interval from 530 to 325
m in particular. It is plausible that swamp deposits have been eroded during episodes during which the water table quickly raised
or during events of sudden coarse fluvial input into the basin.
D 2005 Elsevier B.V. All rights reserved.
Keywords: Bogotá basin; Basin infill; Colombia; Sediment analysis; Pollen analysis; Lacustrine depositional environments
* Corresponding author.
E-mail address: [email protected] (V. Torres).
0031-0182/$ - see front matter D 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.palaeo.2005.05.005
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V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
1. Introduction
The present-day high plain of Bogotá, located at
c. 48N and c. 748W and 2550 m altitude, represents
the floor of an ancient lake. During late Pliocene and
Pleistocene time, this basin was covered by a lake.
Subsidence of the bottom of the basin and inwash of
sediments into this ancient lake that originated from
the catchment area of the relatively small Bogotá
River, kept balance. This hypothesised equilibrium
allowed permanent, relatively shallow lake conditions and gradual accumulation of mainly lacustrine
sediments during the last 3 million years (3 Ma)
(Hooghiemstra and Sarmiento, 1991).
The mainly lacustrine sediments from the intramontane basin of Bogotá were completely sampled
for the reconstruction of environmental changes. We
recovered 586 m of sediments and touched the
bedrock of sandstone. The basin of Bogotá belongs
to the few deep intramontane basins in the world
for which abiotic and biotic proxies were studied in
detail. In previous drilling efforts, the bedrock of
basin of Bogotá was not reached. The Funza-1 core,
located at some 1 km distance, reached 357 m
depth and drilling was stopped for technical reasons
(Hooghiemstra, 1984). Possibly the 195 m deep
core CUY reached the bedrock closely but this
site is located near the eastern rim of the basin
and, as a consequence, shows many gaps in the
sediment record leading to frequent hiatuses of
unknown length (Van der Hammen, unpublished
data).
Most of the previous research on the sediments
of deep boreholes in the high plain of Bogotá was
focussed on pollen analysis leading to reconstructions of vegetation change, floral evolution and
inferred records of climate change (Van der Hammen and González, 1963; Van der Hammen et al.,
1973; Hooghiemstra, 1984; Hooghiemstra and Ran,
1994; Hooghiemstra and Cleef, 1995; Mommersteeg, 1998; Van ’t Veer and Hooghiemstra,
2000). Despite our good understanding of the dynamics of vegetation and flora during the series of
Pleistocene ice ages, and the evolution of high
Andean biomes (Marchant et al., 2002), little is
known about the geomorphological and sedimentological processes. The geological studies by Van der
Hammen et al. (1973) and Helmens (1990) provi-
ded the first approach to synthesise the late Neogene history of the area of Bogotá, based on
lithological information, pollen analysis, paleosol
information and geomorphology.
A good understanding of the sediment record may
lead to high-quality curve matching of climate
records. In a first effort, Torres (1995) showed a
pollen-based stratigraphical correlation of the late
Pleistocene lacustrine sediments of core Ingeominas-1 with the sediments of the Funza-2 core. The
present study shows for the first time, with high
temporal resolution, changes in sediment characteristics along the full 586-m-long core providing a better
understanding of local sediment accumulation processes and offering a basis for improved inter-core
correlations. Lithological information was based on
visual description of the sediments. Downcore analysis of grain size, loss on ignition (LOI) and fossil
pollen content were produced at 20-cm intervals;
thus, the total records consist of c. 2200 sample
points. Absolute chronological control is provided
by K/Ar and fission track datings of volcanic ash
layers interbedded in the clayey and sandy deposits;
data were presented and discussed in Andriessen et
al. (1993).
This paper focuses on the downcore changes of
the sedimentological characteristics and its interpretation in terms of depositional environments and
energy levels. Based on this 2200-sample record
that covers the last 3 Ma, we present a reconstruction
of the abiotic environment in particular. The reconstruction of vegetation change and inferred climate
change, and aspects of the evolution of flora and
biomes will be published elsewhere.
2. Geological setting
The high plain of Bogotá (locally called dSabana
de BogotáT) is located in the Eastern Cordillera of
Colombia. It represents a tectonic-sedimentary basin,
consolidated after the final upheaval of the Northern
Andes, around 5 Ma (Van der Hammen et al., 1973;
Wijninga, 1996) (Fig. 1). The basin is mainly formed
by sandstones of Cretaceous and Palaeogene age.
This sedimentary rock forms surrounding mountains
up to 4000 m altitude, thus reaching to some 1500 m
above the level of the high plain of Bogotá; only at
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
129
Fig. 1. Location of the sedimentary basin of Bogotá in the Eastern Cordillera of Colombia. The present-day high plain represents the floor of an
ancient lake. The location of sites Funza-1 and Funza-2, and other sites mentioned in the text are indicated (modified from CAR, 2001).
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V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
the western side of the basin rocks rise some 200 to
300 m above the high plain before descending rapidly and forming the valley of the Magdalena River.
The slopes and foothills of the mountains, as well as
the flat areas, a.o., the Sabana de Bogotá, contain
sediments of Neogene and Quaternary age.
area. In Fig. 2, the different biozones and the main
taxa characterising the pollen spectra in these zones
are shown. Biozones IV, V, VI and VII, originally
described and published by Van der Hammen et al.
(1973), are present in the lacustrine sediments of the
Funza-2 core.
2.1. Lithostratigraphy
2.3. Chronostratigraphy
Based on stratigraphical information from boreholes, Helmens (1990) defined the lithological units
of the middle part of the basin of Bogotá where the
sediments are not exposed. A summary of the stratigraphy of the high plain of Bogotá is shown in Fig.
2. Helmens (1990) defined four different depositional
environments. Here, we mention only those related to
the lacustrine environment: the Upper Tilatá Formation, the Subachoque Formation, and the Sabana
Formation.
The Upper Tilatá Formation in the sense of Helmens (1990) is part of the Tilatá Formation, defined
by Scheibe (1933) and consists of grey or green
(sandy) clays, organic clays, silts (locally bioturbated), and (clayey) sand, with local intercalation of
peat/lignite horizons, gravel and diatom clays. The
overlying Subachoque Formation, defined in Van der
Hammen et al. (1973), consists of (sandy) clays,
organic clays and peat/lignite horizons that alternate
with (clayey) sand or with (clayey) sand and gravel.
The Sabana Formation was defined by Hubach
(1957) and consists of clays, organic clays, peat/
lignite, sandy clays and (clayey) sand. The Sabana
Formation overlies the Subachoque Formation and is
locally situated directly on top of the bedrock (Helmens, 1990).
Eight intercalated tephra beds from the Funza-2
core were fission track-dated (Andriessen et al.,
1993), providing the tephrochronological framework
of the sequence (Fig. 3). The analysed ash layers
originate from the core interval between 67.76 m
and 506.20 m. As a consequence, the upper 67 m
of the core and the lowermost 80 m of the core
remain without direct time-control. A visual match
between the arboreal pollen record (temperature record) and the B18O record of marine core ODP 677
(eastern Pacific Ocean; Shackleton et al., 1990) was
carried out by Hooghiemstra et al. (1993). They
estimated the age at 340 m depth in the Funza-1
core at c. 1.4 Ma. Accepting this match of the
Funza-1 record to the deep-sea stratigraphy, and
extending this match further downcore in Funza-2,
dmarine agesT were substituted in the pollen record.
However, this results in a discrepancy between the
land–sea correlation and the 3 fission tracks ages
(interval c. 239 to 278 m core depth) (Fig. 3). This
discrepancy can be explained by the quality of the
samples that were available for dating (Andriessen et
al., 1993). Working along this line, we estimated the
base of core Funza-2 at 586 m depth at an age of 3.2
Ma (Fig. 3).
2.4. Tectonic framework of the high plain of Bogotá
2.2. Biostratigraphy
The biostratigraphical framework of the sediments
of the high plain of Bogotá is based on pollen analysis. The successive immigration of four arboreal
taxa (Hedyosmum, Myrica, Alnus and Quercus, respectively) into the area constitutes the main criterion
to separate biostratigraphic units. Furthermore, the
valuable pollen-based ecoclimatic history gives another important criterion to establish biozones (Van der
Hammen et al., 1973; Helmens, 1990; Wijninga,
1996), which complements the biostratigraphy of the
The high plain of Bogotá constitutes an intramontane basin that formed after the strongest uplifted of
the Eastern Cordillera during Pliocene time (Van der
Hammen et al., 1973; Hoorn, 1994; Wijninga, 1996).
The uplifting of the Eastern Cordillera was accompanied by folding and faulting of the sedimentary
sequence that had accumulated during Cretaceous
and Paleogene times. The basin of Bogotá is part
of a complex thrust system with a NNE–SSW tectonic domain (Fig. 1). Initial evidence of the uplifting
of the eastern flank of the Eastern Cordillera during
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
Lithostratigraphy
of Neogene sediments
of the basin of Bogotá
Basin
Biostratigraphy
Central
Holocene
Marginal
es
op
tsl
o
Fo
Immigration
of taxa
Biozores
Chronostratigraphy
131
Nch
Late
VII
Nrt
~25m
Quercus
VI
~320m
Nrt
Nrs
Pleistocene
Middle
Neogene
Alnus
V
~150m
Nsa
Early
IV
Nrt
Nsu
~110m
Nt
~15m
Pliocene
Late
Nc
III
~20m
~35m
Nt
Early
Myrica
II
Nt
Clay
Organic clay/peat lignite
Diatom clay
Silt
Sand
Gravel
Rounded boulders
Stone fragments
Paleosoil
Nsa
Nsu
Nrt
Nt
Fm. Sabana
Fm. Subachoque
Fm. Río Tunjuelito
Fm. Río Tilatá
Nch
Nrs
Nc
Fm. Chía
Fm. Río Siecha
Fm. Chorrera
Fig. 2. Lithostratigraphy, biostratigraphy and chronostratigraphy of the unconsolidated sediment sequence in the basin of Bogotá (modified from
Helmens, 1990).
the Pleistocene has been documented by A. Mora
(personal communication, 2004) based on apatite
fission tracks. However, the high plain of Bogotá
had reached its present altitude (2550 m) before the
accumulation of the Funza sequence started (Helmens, 1990).
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V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
Depth
(m)
0
0.20*106±0.12
100
200
0.26*106±0.18
0.27*106±0.11
0.53*106±0.15
300
1.02*106±0.23
0.20*106±0.12
1.01*106±0.21
400
500
2.74*106±0.63
0.5
1.0
1.5
2.0
2.5
3.0
Ma
Funza I and II Pollen Records
Zircon fission track ages
Control points from the correlation between
Funza I Arboreal
Pollen % record and ODP
18
Site 677 δ O record
Estimate ages of the Pollen Zone
boundaries of Funza II
Fig. 3. Chronology of the sediments of the 357-m long Funza-1 and the 586-m long Funza-2 core from the high plain of Bogotá, Colombia.
Time-control is based on fission track-dated intercalated volcanic ashes and (indirect) matching of the pollen records with B18O record ODP 677
from the eastern Pacific (adapted from Van ’t Veer et al., 1995).
2.5. Aquatic and marsh vegetation
This paper focuses on the environmental development of the basin. Therefore, we are particularly
interested in the records of marsh vegetation and
(submersed) aquatic plants. Thus, in contrast to
other palynological studies with focus on regional
climate change (and using changes in the zonal
vegetation), we here focus on the changes in azonal
vegetation. The ecology of the modern aquatic and
marsh vegetation was studied by Van der Hammen
and González (1963), Cleef (1981), Rangel and
Aguirre (1983, 1986), Cleef and Hooghiemstra
(1984), Kuhry (1988), Wijninga et al. (1989), Cortés
and Rangel (2000), Chaparro (2003).
Rangel (2003) described the actual hydroseries in
the Andean forest belt of the Colombian Eastern
Cordillera and recognized different successional ve-
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
getation communities related to water depth. The
following categories can be recognized: submerged
and emerged aquatic vegetation, floating vegetation,
and shore (swamp) vegetation. An idealised hydroseries for the former lake of Bogotá is shown in Fig.
4. According to Rangel (2003), and based on Cleef
(1981, Cleef, personal communication 2004) the
main plant communities in the former lake of Bogotá
might have been the following:
Submerged and emerged vegetation: Plants are
rooted in the substrate. Part of the plants may be
emerged from the water, or not. The main plant
3
4
133
communities associated with the former lake of
Bogotá most possibly were dominated by:
a) Myriophyllum quitense and Potamogeton illinoiensis. Both species may grow associated or not, in
water of 2 m depth or more. Today both species are
found associated in lakes located in the grassparamo up to c. 3800-m elevation. In the muddy water
of present-day Lake Fúquene (2550 m), Potamogeton illinoiensis is better developed than Myriophyllum quitense. In paramo environments,
Potamogeton illinoiensis has also been documen-
Emergent
2
Heliconia marginata
Begonia fischeri
Hydrocotyle ranunculoides
Ludwigia sp.
m
Floating
Azolla filiculoides
Lemna spp.
Ricciocarpus natans
Eichornia crassipies
Ludwigia sp.
Ludwigia peploides
1
Submerged
Egeria canadensis
Spirogyra sp.
Nitella spp.
Isoëtes spp.
Myriophyllum quitens
1
3
2
0
4
-1
-2
Shore
Typha latifolia
Polygonum spp.
Juncus effusus
Hydrocotyle ranunculoides
Rumex obtusifolium
Epilobium denticulatum
Gratiola bogotensis
Oenothera spp.
Eleocharis spp. (Cyperaceae)
Cotula coronopifolia
Conyza ssp.
Schoenoplectus californicus (Cyperaceae)
Myriophyllum quitense
Ludwidgia inclinata
1
-3
Fig. 4. Position of different categories of plant taxa along an idealised profile at the border of palaeolake Bogotá. Potentially relevant taxa are
arranged in categories that reflect different water depth and show how changes in water level can be inferred from past changes of aquatic
vegetation. Underlined taxa are included in the pollen record of Funza and form the basis for the lake level reconstruction. The figure shows
plant taxa actually present in the vegetation, as well as taxa that might have been present in the past (modified after Rangel (2003); data after
Cortés and Rangel (2000) and Rangel (2003)).
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V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
ted on gravely substrate and swift running water.
Associated species may include Eleocharis acicularis, Isoëtes spp., Lilaeopsis schaffneriana and
aquatic bryophytes, such as Drepanocladus exannulatus and Scorpidium scorpiodes.
b) Najas guadaloupense is associated with Potamogeton illinoiensis and Myriophyllum quitense; near
the shore appear Crassula venezuelenses and Callitriche sp. Species of Nitella (Characeae), according to the transparency of the water column, occur
monodominant in the deeper part of the lake.
Table 1
Plant taxa characteristic of a hydrosere along the border of palaeolake Bogotá
Family
Species
Palynological
identification
level
Apiaceae
Apiaceae
Asteraceae
Asteraceae
Azollaceae
Callitrichaceae
Characeae
Crassulaceae
Cyperaceae
Cyperaceae
Cyperaceae
Haloragaceae
Hydrocharitaceae
Isoetaceae
Juncaceae
Lamnaceae
Lemnaceae
Musci
Musci
Najadaceae
Oenotheraceae
Oenotheraceae
Onagraceae
Phytolacaceae
Poaceae
Polygonaceae
Polypodiaceae
Potamogetonaceae
Ranunculaceae
Solanaceae
Typhaceae
Typhaceae
Hydrocotyle ranunculoides
Lilaeopsis schaffneriana
Bidens laevis
Vazquezia anemonifolia
Azolla filiculoides
Callitriche sp.
Nitella spp.
Crassula venezuelenses
Carex acutata
Eleocharis acicularis
Schoenoplectus californicus
Myriophyllum quitense
Limnobium laevigatum
Isoëtes spp.
Juncus microcephalus
Spirodela sp.
Lemna cf. gibba
Drepanocladus exannulatus
Scorpidium scorpiodes
Najas guadaloupense
Ludwigia inclinata
Ludwigia peploides
Epilobium denticulatum
Phytolacca bogotensis
Cortaderia bifida
Rumex obtusifolius
Polypodium punctatum
Potamogeton illinoiensis
Ranunculus nubigenus
Solanum nigrum
Typha angustifolia
Typha latifolia
Genus
Family
Family
Family
Genus
Not identified
Not identified
Not identified
Family
Family
Family
Genus
Not identified
Genus
Not identified
Not identified
Not identified
Not identified
Not identified
Not identified
Genus
Genus
Family
Not identified
Family
Genus
Genus
Genus
Genus
Genus
Genus
Genus
The downcore changing proportions of the underlined taxa have
been reconstructed; other taxa cannot be identified palynologically.
Note that species could be recognized to the generic or family level
at the best.
Floating vegetation: The floating vegetation forms
colourful patches on the water surface. Characteristic
are Azolla filiculoides, Bidens laevis, Hydrocotyle
ranunculoides, Lemna sp., Limnobium laevigatum
and Spirodela sp. At present day, Limnobium laevigatum is almost limited (endemic) to the area of the
high plain of Bogotá.
Shore vegetation: Plants present along the shore of
the lake, mostly reed swamp communities. The most
important reed swamp communities are:
a) Reed swamp dominated by Typha latifolia and
Typha angustifolia and associated with Bidens laevis, Phytolacca bogotensis, Polypodium punctatum and Rumex obtusifolius.
b) Reed swamp dominated by Schoenoplectus californicus and Juncus microcephalus and associated
with Cortaderia bifida, Ludwigia inclinata, Myriophyllum quitense and Ranunculus nubigenus.
c) Reed swamp dominated by Carex acutata and
Hydrocotyle ranunculoides common in wetland
along the shore.
d) Herb field dominated by Bidens laevis, Phytolacca
bogotensis, Polygonum punctatum and Rumex
obtusifolius and associated with Epilobium denticulatum, Hydrocotyle ranunculoides, Lilaeopsis
schaffneriana, Ludwigia peruviana, Solanum
nigrum and Vazquezia anemonifolia.
Plant taxa that have been identified on the basis of
their pollen grains or spores are listed in Table 1. Most
taxa could be recognized to the generic or family level
at the best.
3. Methods
3.1. Core drilling and lithological description
The Funza-2 core was drilled in 1988 near the
village of Funza, centrally located in the basin of
Bogotá where sediment accumulation was expected
to be maximal (Fig. 1). Sediments were cored with a
dLongyearT drilling equipment and collected in increments of 150 cm. The diameter of the core was 3 in.
(NQ devise) from the top to 369 m, 2 in. (BQ devise)
from 369 to 512 m, and 1.5 in. (AQ devise) from 512 m
to the bottom at 586 m core depth. We used casing up
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
to a depth of 369 m core depth and the borehole was
consolidated with benthonite. The corer touched the
bedrock of sandstone at 586 m below the surface and
caused breaking of the drilling rods: the sampler with
the very last sediment (and a significant amount of
drilling rods) was lost. Sediment samples were conserved in parts of 100 cm, wrapped in plastic foil and
stored in aluminium boxes. Sediment recovery was
mostly 90–100%, only a few number of core increments showed a recovery as low as 80% to 50%.
Between 160 m to 205 m core depth, there were serious
technical problems because of superfluous presence of
subterraneous water. We decided not to core this interval taking into consideration that these sediments are
well represented in the Funza-1 core, located at some
1-km distance. Sediments were sampled in Bogotá,
mainly by H. Hooghiemstra. Samples had to be
cleaned very carefully from benthonite as this ever
circulating drilling mud occasionally had entered the
sediment column along cracks. Samples for pollen
analysis were taken at 20-cm distance, compensating
this distance for the degree of dcompressionT of the
sediments. Horizons with high concentrations of volcanic ash were collected integrally for dating purposes.
Lignite layers, varying in thickness from 1 to 20 cm,
were always sampled and mostly at 2 cm distance
along the core with the aim to arrive at detailed reconstructions of early Pleistocene peat development. The
lithology of the core was described by Arevalo and
Pinzón (1989) using a stereobinocular.
3.2. Grain-size analysis
Samples for grain-size analysis were taken at 20-cm
distance along the core adjacent to the sample holes of
the pollen analysis. Sediments were prepared according
to the methodology described in Konert and Vandenberghe (1997). Grain-size analysis was carried out with
a dFritsch A22 Laser Particle Sizer.T This equipment
distinguishes 57 different grain-size classes which were
categorised here as follows: dclayT b 4.0 Am, dsiltT
between 4.0 and 63 Am, dfiner sandT between 63 and
250 Am, dcoarser sandT between 250 and 2000 Am.
135
lected directly adjacent to those for pollen and grainsize analysis, also at 20-cm distance along the core.
Samples with a wet weight of about 5 g were dried at
105 8C during 12 h; 2 g of the dry sample was taken
and combusted in an oven at 400 8C for 16 h. The LOI
values are expressed as a percentage of dry weight.
The Funza-2 samples do not contain carbonate. Therefore, the loss of weight is due to the organic matter
combustion. We decided to use the abovementioned
conditions (weight, temperature and time) to avoid
possible dehydration of clay minerals, and we assumed that a lower temperature (400 8C) than that
used by Heiri et al. (2001) as well as longer exposure
time (16 h) was enough to burn most of the organic
matter content without destroying clay mineral structures with the risk of releasing formation water.
3.4. Lake level reconstructions based on the record of
the aquatic and marsh vegetation
With the aim to reconstruct lake level changes, Van
’t Veer and Hooghiemstra (2000) plotted the downcore changes in the proportion of aquatic plants that
are characteristic of various water depth. Although
aquatic and marsh plants may show a significant
range in their ecological affinity, the general picture
is conclusive. From Funza-1 record, it appears that, on
the average, high water levels occurred during cold
(glacial) episodes and lower water levels are characteristic of warmer (interglacial) episodes. According
to Van ’t Veer and Hooghiemstra (2000), the following taxa represent a gradient of increasing water
depth: Myriophyllum, Cyperaceae, Ludwigia, Hydrocotyle and Isoëtes. In this paper, we used the same
method to reconstruct changes in the water table at the
site of Funza-2. In addition, we combined the results
of the biotic proxy with our newly elaborated abiotic
proxies, viz. grain-size and LOI, to reconstruct lake
level fluctuation as reliably as possible.
4. Results
4.1. Sedimentary facies of the lake deposits
3.3. Organic matter content
We determined the organic matter content of the
sediments by measuring the LOI from samples col-
Based on a visual description of the sediments and
grain-size analysis of some 2220 samples, we recognized 10 distinct sedimentary facies ranging from fine
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V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
to coarse sediments. In this sequence, facies 1 represents the finest one (mainly b4 Am) and facies 10
represents the coarsest one (mainly N 250 Am) (Fig. 5).
In addition, facies 11 was established on the basis of
(a) Facies 1
(b) Facies 2
(263.20 m)
Clay
Silt
Sand
6
Percentage (%)
Percentage (%)
10
the lithological description and the organic matter
content. Facies 2 to 9 contain a mix of fine fractions
(clay and silt) and coarse fractions (sand) with a
gradual increase in both the amount and size of the
8
6
4
2
0
0.24 0.49 0.98 2
(35.80 m)
Clay
Silt
4
3
2
1
0
3.9 7.8
16
31
0.24 0.49 0.98
63 125 250 500 1000 2000
2
3.9
Grain diameter (µm)
(c) Facies 3
Clay
Silt
12
Percentage (%)
Percentage (%)
Sand
3
2
1
3.9 7.8
Clay
Silt
Clay
8
6
4
16
31
2
63 125 250 500 1000 2000
0.24 0.49 0.98 2
3.9 7.8
31
63 125 250 500 1000 2000
4
3
2
1
(119.40 m)
Clay
Sand
Silt
20
Percentage (%)
Percentage (%)
(f) Facies 6
Silt
Sand
15
10
5
0
2
3.9 7.8
16
(g) Facies 7
31
63
125 250 500 1000 2000
0.24 0.49 0.98 2
3.9 7.8
Clay
Silt
16
31
63
125 250 500 1000 2000
Grain diameter (µm)
(h) Facies 8
(342.30 m)
4
3
2
1
(422.60 m)
Clay
Sand
Silt
10
Percentage (%)
5
Percentage (%)
16
Grain diameter (µm)
Grain diameter (µm)
Sand
8
6
4
2
0
2
3.9 7.8
16
31
63 125 250 500 1000 2000
0.24 0.49 0.98 2
3.9 7.8
Grain diameter (µm)
(i) Facies 9
(j) Facies 10
(574.80 m)
Clay
Silt
2
1
3.9 7.8
16
31
63
125 250 500 1000 2000
Grain diameter (µm)
31
63 125 250 500 1000 2000
(446.00 m)
Clay
Sand
3
2
16
Grain diameter (µm)
Silt
25
Percentage (%)
Percentage (%)
Sand
10
(84.20 m)
5
0
0.24 0.49 0.98
63 125 250 500 1000 2000
0
2
(e) Facies 5
4
31
(118.40 m)
Grain diameter (µm)
0
0.24 0.49 0.98
16
(d) Facies 4
4
0
0.24 0.49 0.98
7.8
Grain diameter (µm)
(525.20 m)
5
0
0.24 0.49 0.98
Sand
5
Sand
20
15
10
5
0
0.24 0.49 0.98 2
3.9 7.8
16
31
63
125 250 500 1000 2000
Grain diameter (µm)
Fig. 5. Selected examples of histograms of grain size distributions that are characteristic of the ten different facies recognised in the Funza2 core.
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
137
than 5% of sand (Fig. 5a). Deposition of sediments
belonging to facies 1 takes place by settling in
completely standing water, reflecting a very lowenergy level in a full lacustrine environment.
Facies 2 contains overall a fine sediment fraction
(b 63 Am), which is slightly coarser than facies 1. It
contains less than 5% of sand and shows a bimodal
distribution of which the finer fraction equals facies
1 (Fig. 5b). The coarser (silt) fraction represents
fine suspension sediment supply from offshore
sources probably transported by run-off. The ener-
coarse fractions (sand): facies 3 slightly coarser than
facies 2, facies 4 slightly coarser than facies 3, etc. In
Fig. 6, the depositional environments of the recognized facies are shown in a schematic cross-section
through the lake: the level of energy regime (Fig. 6A)
and the organic matter content of the sediments (Fig.
6B) are the main gradients. In the next section, the
facies are characterised.
Facies 1 corresponds with the finest sediment fraction (b 8 Am) with unimodal distribution and less
(a)
Lacustrine deposits
Fluvio-lacustrine deposits
Fluvial deposits
F-9
F-7
Suspension load
Standing water
F-8
F-5
F-10
F-6
F-4
F-3
F-2
F-1
Lower
E
Higher
i
Marsh vegetation
(b)
Swamp deposits
Lacustrine deposits
Standing water
Facies 11
Peat/lignite
Facies 1 (F-1)
Facies 2
c-ri
ani
g
r
O
Lower
Organic matter content
m
ch
ud
Higher
Fig. 6. Schematic profile through paleolake Bogotá showing the distribution of facies. Panel (A) shows the distribution of facies along an energy
gradient in a lake with input of mainly fluvial bedload (F-4, F-6, F-8 and F-10), and mainly suspension load (F-3, F-5, F-7 and F-9). Panel (B)
shows the distribution of facies in a lake with only fluvial suspension input (lacustrine setting) and the distribution of organic matter in the
sediments.
138
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
gy level acting on the lake floor is very low, but a
bit higher than conditions under which facies 1
accumulated.
Facies 3 is composed of a mix of clay, silt and very
fine sand (63 to 125 Am). The amount of sand is
lower than 30% (Fig. 5c). The grain-size distribution suggests this facies accumulates in a closed
lake environment (Sun et al., 2002). Compared to
facies 2, the energy level acting on the floor of the
lake is slightly higher.
Facies 4 is mainly composed of clay, very fine sand
(63 to 125 Am) with small admixture of silt (Fig.
5d). The accumulation of facies 4 takes also place
in a lacustrine environment, but compared to facies
3 under conditions with a higher energy level.
From the distribution curve, we infer the presence
of fluvial input (sand fraction) into an open lake
environment.
Facies 5 is a badly sorted mix of clay, silt and sand
(Fig. 5e). It resembles facies 3, but the sand fraction is coarser (125 to 250 Am). The amount of
sand represents less than 30%. Sediments of facies
5 derive from fluvial input, after which the suspension load (from very fine sand to clay) is settled.
The accumulation of this facies takes place in a
lacustrine environment under low level energy conditions acting on the floor of the lake. The distribution curve resembles that showed in Sun et al.
(2002) for a lacustrine environment. This facies
represents the accumulation of suspension load
after fluvial sediment input. From facies 4 to facies
5, the energy level acting on the lake floor gradually is increasing.
Facies 6 is mainly composed of fine sand (125 to
250 Am). A small amount of clay and silt (less than
30%) makes also part of this facies (Fig. 5f). It
resembles quite well facies 4, but the sand fraction
is coarser. In contrast, the fluvial sand is similar to
facies 5, but in facies 6, the suspension loaded is
almost absent. The distribution curve resembles
that shown in Kasse et al. (1995) for infill channel
deposits. Therefore, we suggest facies 6 has a
fluvial or fluvio-deltaic origin.
Facies 7 and 8 resemble well facies 5 and 6,
respectively, but the sand fraction is coarser (250
to 500 Am). Facies 5 and 7 have a high suspension
load, contrasting with facies 6 and 8 (Fig. 5g–h).
The energy level acting on the lake floor is higher
than that in facies 5 and 6, explaining the accumulation of coarser fluvial material.
Facies 9 is comparable to facies 7 but the sand
fraction is still somewhat coarser, while the clay
content is higher (Fig. 5i). This facies with poorly
sorted sediments reflects the alternation of conditions of a high-energy level with conditions characterised by long periods without any fluvial
input. We propose this facies reflects an environment with sedimentation in an open lake, alternating with fluvial input.
Facies 10 is comparable to facies 8 but does not
contain silt to clay sized suspension load at all.
Thus facies 10 consists of medium, coarse and very
coarse, moderate to well-sorted sand (250 to 2000
Am) (Fig. 5j). The distribution curve resembles that
showed in Kasse et al. (1995) for bedload of channel deposits. In comparison with the facies 1 to 9,
facies 10 represents the highest energy regime
acting on the basin floor.
Facies 11 is composed of peat (or lignite) and
organic-rich mud (b63 Am). The clay fraction of
this facies accumulated in standing water conditions, with input of sediments from onshore when
also a silt fraction is present. This facies represents
swamp and shallow water conditions.
4.2. Facies association and depositional environment
Following the recognition of the facies described
above, we established four discrete depositional environments in which the sediments of the Funza-2 core
have accumulated. The downcore distribution of facies, and inferred depositional environments, are
shown in the Figs 7, 8 and 9. Each of the four
identified depositional environments is characterised
and depicted in a schematic block diagram (Fig. 10).
4.2.1. Lacustrine deposits
Facies 1 and 2 represent sediment accumulation in
a lake with a very low-energy regime. We infer a
shallow lake environment with (potentially) submerged vegetation. Gradual transitions from facies 1
to facies 2 and vice-versa reflect relatively small
changes in the energy level acting on the floor of
the lake. The transition from facies 1 to facies 2
shows an increase of the energy regime, transporting
silt from far distance to the coring site. These transi-
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
139
Isoëtes
Current ripples
Clay
LOI
Wavy lamination
Sandy clay
Clay fraction
Bioturbation
Sand
Silt fraction
Burrows
Lithological discontinuity
Sand (63-250µm)
Root remains
Plan remains
Organic debris
Sand (250-2000µm)
Swamp deposits
Myriophyllum & Ludwigia
Lacustrine deposits
Clayey clasts
Hydrocotyle
Fluvio-lacustrine deposits
Peat/lignite
Cyperaceae
Fluvial deposits
En
v v v
Aquatic vegetation
1OO O
1OO
Clay, silt and LOI
1OO
Sand
O
75
85
2
v vv
90
95
O
Lithology
O
Lithology
80
clay
silt
very fine sand
fine sand
medium sand
coarse sand
very coarse sand
gravel
v
Fa iron
ci m
e e
D s nta
l
ep
th
(m
)
Volcanic layer
Muscovite
2
11
clay
silt
very fine sand
fine sand
medium sand
coarse sand
very coarse sand
gravel
Rich organic clay
En
v
Fa iron
ci m
es en
ta
D
l
ep
th
(m
)
CONVENTIONS
Parallel lamination
Aquatic vegetation
1OO O
1OO
Clay, silt and LOI
1OO
Sand
O
100
0
11
2
5
105
11
10
2
11
2
11
110
115
15
2
6-4
20
Sabana Formation
2
25
1
125
2
1
30
120
2
v vv
130
Sabana Formation
2
11
35
40
2
5
135
2
140
5
145
v vv
v vv
45
2
11
2
6
2
50
150
2
v vv
55
155
10
2
60
11
10
160
65
165
70
170
75
175
No core recovery
2
11
2
Fig. 7. Synthesis of proxies of core Funza-2 for the interval 5–175 m core depth. From left to right are indicated: geological formation,
depositional environment, facies, depth scale, lithology, main pollen diagram of aquatic taxa indicative of lake level changes, grain-size analysis,
and LOI record.
140
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
Fig. 8. Synthesis of proxies of core Funza-2 for the interval 185–385 m core depth. From left to right are indicated: geological formation,
depositional environment, facies, depth scale, lithology, main pollen diagram of aquatic taxa indicative of lake level changes, grain-size analysis,
and LOI record.
5
O
Lithology
Aquatic vegetation
1OO O
1OO
Clay, silt and LOI
1OO
Sand
O
385
141
clay
silt
very fine sand
fine sand
medium sand
coarse sand
very coarse sand
gravel
En
v
Fa iron
ci m
es en
ta
D
l
ep
th
(m
)
clay
silt
very fine sand
fine sand
medium sand
coarse sand
very coarse sand
gravel
En
v
Fa iron
ci m
es en
ta
D
l
ep
th
(m
)
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
O
Lithology
Aquatic vegetation
1OO O
1OO
Clay, silt and LOI
1OO
Sand
O
485
11
2
5
390
490
2
5
11
5
11
395
8
11
10
6
495
2
6
11
400
2
500
3
5
11
2
405
505
1
v v v
v v v
v v v
11
6
410
510
2
1
11
2
4
415
3
5
6
8
11
420
7
2
6
425
520
6
10
2
3
525
2
11
11
430
2
11
6
2
3
6
435
2
440
v v v
Subachoque Formation
Subachoque Formation
515
2
1
6
530
6
2
5
2
535
540
11
2
445
1
545
10
3
2
6
450
10
11
455
3
6
4
2
10
550
555
1
2
460
1
560
465
2
565
11
3
10
8
1
11
10
470
11
3
11
2
4
8
1
2
570
3
475
9
575
5
480
11
1
11
1
7
2
9
9
5
580
6
3
485
5
585
Fig. 9. Synthesis of proxies of core Funza-2 for the interval 385–585 m core depth. From left to right are indicated: geological formation,
depositional environment, facies, depth scale, lithology, main pollen diagram of aquatic taxa indicative of lake level changes, grain-size analysis,
and LOI record.
142
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
(e)
(d)
(c)
(b)
Forest
(a)
Swamp and marsh vegetation
Sand deposits
Peat/lignite
Clay and silt sediments
Drilling place
Fig. 10. Schematic block diagrams showing the setting of four depositional environments, inferred from the downcore changes of 11 different
facies: (a) fluvio-lacustrine deposits during low water stands, (b) shallow lacustrine and swamp deposits during low water stands, (c) swamp
deposits, (d) fluvio-lacustrine deposits during high water stands, (e) lacustrine deposits.
tions might be caused by raising and falling water
tables, which means a varying distance of the coring
site to the shore, or varying rates of erosion in the
surroundings of the lake. In this facies, clay and silt
represent the finest suspended detrital fractions becoming somewhat coarser in the facies nearer to the
shore (Fig. 6). The modal value of the silt fraction (9
to 10 Am) in facies 2 is smaller than that found in the
Chinese loess (20 to 50 Am) (Sun et al., 2002, 2004)
and those of the dRed ClayT from northern China (8 to
16 Am) (Lu et al., 2001; Vandenberghe et al., 2004).
Therefore, we discard any aeolian origin for these
deposits. We consider that the silt fraction of facies
2 was supplied to the coring site from superficial runoff. Even during glacial conditions, when the palaeolake of Bogotá was located in the paramo belt, pollen
evidence (Torres and Hooghiemstra, unpublished
data) shows the presence of vegetation around the
lake, which probably acted as a barrier for wind
erosion. Furthermore, the presence of algae and pollen
grains of aquatic plants (Hooghiemstra, 1984; Van der
Hammen and Hooghiemstra, 1997; Torres and Hooghiemstra, unpublished data) confirms the lacustrine
environment.
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
4.2.2. Swamp deposits
Organic-rich mud and peat/lignite deposits from
facies 11 accumulated during low water level stands
in a low-energy regime. These deposits represent the
formation of swamps and marshes at the coring site,
where abundant swamp vegetation could develop. In
this facies sediment mixing varies from highly bioturbated organic-rich mud to very well laminated
peat/lignite deposits. This indicates different levels
of (biological) activity of the soil fauna whereas
laminated peat accumulated under anoxic conditions.
In the upper 332 m of the record, swamp deposits
(facies 11) were hardly found interbedded between
lacustrine deposits (facies 1 and 2). In most cases,
lacustrine deposits transgrade gradually to swamp
deposits, indicating a slowly falling water table. In
most cases, the transition from swamp deposits to
lacustrine deposits is sharp which might be indicative of a quickly rising water table. For the core
interval below 333 m, up to the base of the core,
swamp deposits constitute more than 5% of the
sequence and appear intercalated with lacustrine,
fluvio-lacustrine and fluvial deposits, showing abundant changes in the energy regime on the floor of
the lake. Like in the upper part of the sequence, the
lower boundaries of the swamp deposits are, in
general, gradual while the upper boundaries are
sharp. This reflects slowly lowering water tables
and quickly rising water levels.
4.2.3. Fluvio-lacustrine deposits
A mix of clay, silt and sand composes facies 3, 4,
5, 7 and 9. Clay accumulated in standing water
conditions while silt and sand represent the input
of sediments from the land surface surrounding the
lake. We interpret this input of silt and fine sand as
the suspension load resulting from fluvial activity at
shorter distance to the lake shore than it was the case
during the deposition of facies 1 and 2. The medium
and coarse sand fractions may be interpreted as the
saltation fraction of the fluvial deposits. Both the
proportion of sand and the size of its grains depend
on the energy on the floor of the lake and the
proximity of the rivers to the coring site. In the
uppermost 332 m of the Funza-2 core, fluvio-lacustrine deposits represent less than 5%, while these
deposits represent more than 5% in the lower part
of the core.
143
4.2.4. Fluvial deposits
We interpret facies 6, 8 and 10 as fluvial deposits.
In these facies, the saltation component represents
more than 70% and the grain-size ranges from c.
100 to 1000 Am. In general, the saltation component
is well sorted for each facies, whereas the suspension
component shows a bimodal distribution and is poorly
sorted. According to Sun et al. (2002), fluvial sediment is characterised by partially overlapping coarse
and fine components, each with stable percentages.
The coarse component of the fluvial sediment is well
sorted, while the fine component is poorly sorted.
Fluvial deposits are rare in the upper 440 m of the
core, but from this depth to the base of the core fluvial
deposits represent at least 5% to 10% of the sequence.
In general, fluvial deposits are gradually overlain by
fluvio-lacustrine deposits. At their top, these fluvial
deposits are gradually transformed into fluvio-lacustrine deposits, indicating a slow decrease in the energy
regime. Sharp boundaries between fluvial deposits
and swamp deposits are common in the interval of
335 to 500 m core depth, which may indicate lateral
migration of channels through the swampy area. For
the interval of 5 to 335 m, fluvial deposits present
sharp boundaries with lacustrine deposits, representing sudden increases of the energy regime at the
coring site.
5. Discussion of the Plio-Pleistocene sedimentary
environments
5.1. Basin infill
Based on the recognition of associations of facies
in the sediment column of core Funza-2, and the
interpretation of these associations of facies into
paleoenvironmental settings, we recognized 7 intervals over the full core length, called dunits.T Sedimentation processes and the paleoenvironmental setting
are reconstructed for each unit (Figs. 7, 8 and 9).
Unit 1 (from 586 to 530 m). The start of sedimentation in the basin of Bogotá is evidenced by the
accumulation of a mix of clay, silt and sand in a
fluvio-lacustrine environment (core interval 586–568
m). Bioturbation and high oxidation rates are recognized providing evidence of sediment accumulation in
shallow water. The water table rose and lacustrine
144
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
facies became dominant in the core interval from 568
to 530 m. Fig. 10a and b illustrate quite well the
possible paleoenvironment during the accumulation
of unit 1. The gradual succession of fluvio-lacustrine
to lacustrine facies suggests a rise of the water table.
Unit 1 is characterised by low values of LOI (b 5%)
with few peaks above 10%. These peaks could be
interpreted as episodes during which high decomposition and oxidation rates prevailed.
Unit 2 (from 530 to 460 m). Shallow lacustrine and
swamp conditions became important in this interval.
Peat/lignite and clays that are rich in organic matter
dominate the sediments. A schematic block diagram
of this swamp environment (Fig. 10b) illustrates the
depositional environment of unit 2. During low water
stands fluvial activity (Fig. 10a) interrupted the
swampy deposition. Sharp boundaries at the base of
the fluvial facies represent discontinuities in the record. The LOI percentages show several peaks which
closely correspond to the presence of peat/lignite
layers. This reflects a better preservation of the organic matter during unit 2 compared to the previous unit.
Unit 3 (from 460 to 445 m). This unit begins with a
lithological discontinuity and in the overlying almost
15 m of sandy sediments a fluvial depositional environment is evidenced. During low water stands fluvial
activity is dominating unit 3 (Fig. 10a). A few times,
these sandy deposits are interrupted by interbedded
peat/lignite layers, reflecting periods of a quiet sedimentary environment and swampy conditions (Fig.
10b). Low LOI values (b2%) are indicative of low
proportions of organic matter and poor preservation.
Unit 4 (from 445 to 325 m). A sequence of fluviolacustrine, lacustrine, and swamp deposits overlie the
fluvial sediments of the previous unit. This reflects a
repeatedly rising and falling of the water table, as well
as a constantly alternating energy level acting on the
floor of the lake. In general, fluvial sediments cut the
lacustrine and swamp deposits with sharp boundaries,
reflecting lithological discontinuities in this unit.
Where LOI values are N 20%, these core intervals
closely correspond to the presence of peat/lignite
layers (facies 11). In contrast, clayey and sandy material is present where LOI values are b15%.
Unit 5 (from 325 to 205 m). This unit is dominated
by sediments belonging to facies 1 and 2 and represent
depositional environments with the highest water level.
During this episode, the basin of Bogotá experienced
proper lacustrine conditions (Fig. 10e). From the previous unit to this one, subsidence of the floor of the
sedimentary basin continued enabling the accumulation of lacustrine deposits in a very low-energy regime.
Fluvial deposits in unit 5 were accumulated during high
water stand (Fig. 10d). LOI values hardly reach 10%,
suggesting that the organic matter in the sediments
mainly originated from swampy environments.
Unit 6 (from 162 to 5 m). This core interval is
dominated by lacustrine sediments pointing to continuous lake environments at the coring site. There
are a few episodes with sudden input of fluvial
sediments (Fig. 10d), and during some periods, the
water table lowered so much that swamps were able
to develop (Fig. 10c). Like in the previous unit 5,
fluvial deposits accumulated during higher water
stands compared with the accumulated in low
water stands prevailing in units 2, 3 and 4 (Fig.
10a,b). LOI values do not differ much from the
values in the previous unit 5; the highest LOI values
coincide with presence of facies 11.
Unit 7 (from 5 to 0 m). The upper 5 m of sediments recovered in the Funza-2 core are composed of
a mix of clay, sand and gravel of fluvial origin. There
is one interbedded paleosol (Helmens, 1990). The
sediments of unit 7 belong to the Chı́a Formation
and yield an unconformity with the underlying clays
that belong to the Sabana Formation. The sharp
erosional boundary at 5 m core depth suggests that
a part of the archive of lacustrine sediments was lost.
Low LOI values (b2%) suggest poor preservation of
the organic matter in this unit.
5.2. Aquatic and swamp vegetation and lake level
fluctuations
In previous studies, the fossil pollen record of the
aquatic and swamp vegetation has been used to reconstruct fluctuations in the water table of ancient
Lake of Bogotá (e.g., Hooghiemstra, 1984, 1989;
Van ’t Veer and Hooghiemstra, 2000). This approach
was also used in the paleoecological studies of Lake
Fúquene (e.g., Van Geel and Van der Hammen, 1973;
Mommersteeg, 1998). In general, high percentages of
Isoëtes have been interpreted as indicative of a high
lake level (Hooghiemstra, 1984; Mommersteeg,
1998). In the Funza-2 record, high percentages of
Isoëtes closely coincide with the presence of facies
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
1 and 2, which in general reflect a lacustrine environment. In unit 5 (interval 325–205 m) Isoëtes shows
high percentages and is dominating (Fig. 8), supporting the functional relationship between a high abundance of Isoëtes and a high water table in the lake.
Nevertheless, Isoëtes seems to be associated also with
fluvial and fluvio-lacustrine facies in units 2, 3 and 4
(i.e., at 523 m, 455 m, 448 m, 422.5 m, 409 m, and
386 m core depth). Cortés and Rangel (2000) found
Isoëtes glacialis associated to the plant community of
Potamogeton berteroanus and Scorpidium scorpioides growing typically on the bank of small rivers.
This plant community could also have been present in
the past, explaining the high percentages of Isoëtes in
the fluvial deposits. In this case, high percentages of
Isoëtes are more associated with fluvial activity rather
than indicative of high lake level stands.
For units 2, 3 and 4 (interval from 325 to 586 m
core depth), the intercalation of swamp, lacustrine,
fluvio-lacustrine and fluvial deposits suggests continuous changes in the sedimentary environment (Figs.
8 and 9). These changes may be related to fluctuations
in the water table, lateral migrations of the streams in
the study area, or changes in the energy regime; all
causes could affect the aquatic and swamp vegetation
leading to migration and succession. For units 5 and 6
(interval from 5 to 325 m core depth), lacustrine
deposits dominate the sequence (Figs. 7 and 8). As
proposed by Van ’t Veer and Hooghiemstra (2000),
changes in the water table can be inferred from the
ratio dabundance of IsoëtesT and the dabundance of
swamp vegetation.T
5.3. Lithological discontinuities in the record and age
of the sediments
Fig. 3 shows the relationship between depth and
age of the sediments in the basin of Bogotá. The graph
of Funza-1 core results from a matching of the arboreal pollen record (reflecting temperature change)
with the B18O record of marine core ODP 677 (Shackleton et al., 1990; Hooghiemstra et al., 1993; Hooghiemstra and Shackleton, unpublished data). The
arboreal pollen record of Funza-2 was also (tentatively) matched with the B18O record of core ODP 677.
Established ages of maxima, minima, and sharp transitions of the marine oxygen isotope stratigraphy
(Imbrie et al., 1984) were related to corresponding
145
characteristics of the arboreal pollen records, leading
to the depth vs. time graph for Funza-2 (Fig. 3). This
provisional curve matching will be reconsidered now
we have the complete data set of 2063 pollen spectra
available (Torres et al., in preparation). According to
Fig. 3, the uppermost 350 m of sediments in the basin
of Bogotá accumulated during the last 1.4 Ma, the
lowermost 236 m of sediments (from 350 to 586 m)
were deposited during a period of 1.8 Ma (from 1.4 to
3.2 Ma). Thus, the uppermost 350 m of the sequence
accumulated almost twice as fast (4000 years/m of
sediment) as did the sediments below 350 m (7630
years/m). Taking into consideration the unknown
number of gaps in the sediment record for the lower
part of the core, sediment accumulation might have
been even more than twice as fast before 1.4 Ma than
after this date.
Considering the heterogeneity of facies for the
lower part of the sediment core, and the variety of
depositional environments near the coring site, and
also considering that:
a) the sedimentation rates that prevailed during the
deposition of the different units changed through
time because the depositional environment
changed along the record. In general, sand accumulates in shorter time than silt and clay. As a
consequence, a given length of the core represents
periods of different length,
b) peat/lignite will be significantly compacted during
diagenesis, reducing its thickness. This applies
mainly to units 4 and 6 where facies 11 is dominant,
c) sharp lower boundaries between fluvial deposits and
swamp deposits in units 2 and 4 represent lithological discontinuities and potential gaps in the core,
d) fluvial activity represented by facies 6, 8 and 10
might have eroded part of the underlying deposits
previously accumulated, and
e) units 5 and 6 are mainly composed of lacustrine
deposits with almost no interruptions in the process
of accumulation,
we propose that:
1. every lithological discontinuity recognized in the
Funza-2 core represents a gap in the sediment
record and, as a consequence, a possible hiatus in
the paleoenvironmental reconstruction,
146
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
2. facies 11 represents more dgeological timeT than,
e.g., the sandy facies 6, 8 and 10 because peat/
lignite has a higher degree of compaction than
sands, and
3. a continuous sedimentation during units 5 and 6,
with the exception of few interruptions in unit 6 in
particular when fluvial activity took place.
These considerations support previous conclusions
that the lower 236 m of the record (core interval from
350 to 586 m) represents a significantly longer time
interval (1.4 to 3.2 Ma) in comparison with the upper
350 m of the core (1.5 to c. 0.028 Ma). This is
explained by the presence of many hiatuses in units
2, 3 and 4, and by the high rate of compaction of the
peat/lignite horizons in the same units. Nevertheless, a
new effort of curve matching between the Funza cores
and selected marine B18O records is necessary to
assure chronological control of the sediments of the
Funza-2 core.
6. Conclusions
Associations of facies reflect 4 different depositional environments: lacustrine environment, swamp
environment, fluvio-lacustrine environment, and a fluvial environment.
Basin infill started with accumulation of fluviolacustrine sediments between 586 and 530 m. During
the time represented by the sediments between 530
and 325 m paleoenvironmental conditions consisted
of shallow water lacustrine environments and
swamps, in combination with some fluvial activity.
From 325 m to 5 m, lacustrine environment prevailed
almost without interruption.
In core intervals where lacustrine conditions were
dominant, changes in the proportions of aquatic and
swamp vegetation give evidence of shifting water
levels. Under fluvial and fluvio-lacustrine depositional regimes, the use of Isoëtes as an indicator of high
water levels is not consistent because is a common
taxa on the bank of small rivers in the high plain of
Bogotá.
Several lithological discontinuities, evidenced by
sharp transitions from swamp deposits to fluvio-lacustrine and fluvial deposits, are present in the core, in
the interval from 530 to 325 m in particular. It is
plausible that swamp deposits have been eroded during episodes when the water table increased quickly,
or during events of sudden input of coarse fluvial
sediments into the basin.
The lowest 286 m of sediments (586 to 350 m)
represent 1.8 Ma of time while the upper 350 m of
sediments (350–2 m) represent 1.4 Ma of time. Different accumulation processes during different periods
explain this time vs. depth relationship. In the upper
350 m, sedimentation was almost uninterrupted. In the
interval from 586 to 350 m core depth lithological
discontinuities between fine-grained facies and
coarse-grained facies evidence numerous (small)
gaps in the sediment record.
Acknowledgements
The completion of the multi-proxy analysis of the
Funza-2 core extended over almost 15 years. Pollen
analysis was conducted by H. Hooghiemstra, E. Ran
and V. Torres. Analysis of LOI and grain-size classes
was carried out by N. de Wilde and V. Torres under
supervision of M. Konert (Vrije Universiteit, Amsterdam). We thank the drilling crew of the Geological
Survey of Colombia (Ingeominas), in particular G.
Sarmiento and D. Mosquera, for their support during
the coring activities which were interrupted several
times by technical problems. Dr. Castro from Smith
International Company (Bogotá) is acknowledged for
making fishing equipment available when broken
drilling pipes had to be recovered at great depth. We
thank COLCIENCIAS for the financial support provided to Ingeominas for the acquisition of a new
Longyear drilling equipment to raise the core. We
thank S.R. Arevalo-Gamboa and I.D. Pinzon-Villazon
for the detailed lithological description of the sediments. Carol Patiño collected extra samples to complete the multi-proxy analysis. We thank P.
Andriessen (Vrije Universiteit, Amsterdam) for absolute chronological control. We are much indebted to
E. Beglinger and A. Philip for preparing all pollen
samples. Closely related research projects were carried out by R. Van ’t Veer, H. Mommersteeg and J.C.
Berrio: we thank all of them for the stimulating atmosphere. Prof. Antoine Cleef (University of Amsterdam) carefully checked the ecology of the aquatic and
marsh vegetation. This research was carried out with
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
financial support from The Netherlands Foundation
for Scientific Research (NWO) to H. Hooghiemstra
(dChristian and Constantijn Huygens FellowshipT W
75-168), and grant H 75-284 to H. Hooghiemstra/E.
Ran. The University of Amsterdam (IBED) provided
financial support to H. Hooghiemstra/V. Torres; during this 4-year period the analysis of Funza-2 sediments was completed. We thank our Colombian
colleagues, T. Van der Hammen in particular, for the
support in initiating this drilling project and for a wide
spectrum of help during the full period of analysis. We
also thank M. Bush, H. Behling and an anonymous
reviewer for their valuable comments to improve the
manuscript.
References
Andriessen, P.M.A., Helmens, K., Hooghiemstra, H., Riezebos,
P.A., Van der Hammen, T., 1993. Absolute chronology of the
Pliocene–Quaternary sediment sequence of the Bogotá area,
Colombia. Quaternary Science Reviews 12, 483 – 501.
Arevalo, S., Pinzón, I., 1989. Análsis sedimentológico de núcleos
extraı́dos del pozo estratigráfico Funza-2, Municipio de Funza,
Cundinamarca. Undergraduate Thesis, Universidad Nacional de
Colombia, Bogotá D.C., 74 pp.
Chaparro, B., 2003. Reseña de la vegetación en los humedales de la
Sabana de Bogotá. In: Bogotá, A.D., C. Conservación Internacional (Eds.), Los Humedales de la Sabana de Bogotá. Zetta
Comunicadores, Bogotá, pp. 71 – 89.
Cleef, A.M., 1981. The vegetation of the paramos of the Colombian
Cordillera Oriental. Dissertationes Botanicae, 61. Vaduz, Berlin,
321 pp.
Cleef, A.M., Hooghiemstra, H., 1984. Present vegetation of the
area of the high plain of Bogotá. In: Hooghiemstra, H. (Ed.),
Vegetational and climatic history of the high plain of
Bogotá, Dissertationes Botanicae, 79, pp. 42 – 66 (J. Cramer,
Vaduz).
Corporación Autónoma Regional de Cundinamarca, CAR., 2001.
Atlas ambiental. Corporación Autónoma Regional de Cundinamarca, CAR, 175 pp, Bogotá.
Cortés, S., Rangel, O., 2000. Los relictos de vegetación de la
Sabana de Bogotá. In: Aguirre, J. (Ed.), Memorias del Primer
Congreso Colombiano de Botánica. Instituto de Ciencias Naturales, Bogotá.
Heiri, A., Lotter, A.F., Lemcke, G., 2001. Loss on ignition as a
method for estimating organic and carbonate content in sediments: reproducibility and comparability of results. Journal of
Paleolimnology 25, 101 – 110.
Helmens, K., 1990. Neogene–Quaternary geology of the high plain
of Bogotá, Eastern Cordillera, Colombia (stratigraphy, palaeoenvironments and landscape evolution). Dissertationes Botanicae
163, 202 pp. J. Cramer, Berlin-Stuttgart.
147
Hooghiemstra, H., 1984. Vegetational and climatic history of the
high plain of Bogotá, Colombia. Dissertationes Botanicae 79,
368 pp. J. Cramer, Vaduz.
Hooghiemstra, H., 1989. Quaternary and Upper Pliocene glaciations and forest development in the tropical Andes: evidence
from a long high-resolution pollen record from the sedimentary
basin of Bogotá, Colombia. Palaeogeography, Palaeoclimatology, Palaeoecology 12, 11 – 26.
Hooghiemstra, H., Cleef, A.M., 1995. Pleistocene climate changes,
environmental and generic dynamics in the north Andean Montane forest and paramo. In: Churchill, S. (Ed.), Biodiversity and
Conservation of Neotropical Montane Forest. The New York
Botanical Garden, Bronx, NY, pp. 35 – 49.
Hooghiemstra, H., Ran, E.T.H., 1994. Late and middle Pleistocene
climatic change and forest development in Colombia: pollen
record Funza II (2-158 core interval). Palaeogeography, Palaeoclimatology, Palaeoecology 109, 211 – 246.
Hooghiemstra, H., Sarmiento, G., 1991. Long continental pollen
record from a tropical intermontane basin: late Pliocene and
Pleistocene history from a 540-meter core. Episodes 14,
107 – 115.
Hooghiemstra, H., Melice, J.L., Berger, A., Shackleton, N., 1993.
Frequency spectra and palaeoclimatic variability of the highresolution 30–1450 ka Funza-1 pollen record (Eastern Cordillera, Colombia). Quaternary Science Reviews 12, 141 – 156.
Hoorn, C., 1994. Miocene palynostratigraphy and palaeoenvironments of northwestern Amazonia: evidence for marine incursions and the influence of Andean tectonics, PhD thesis,
University of Amsterdam, Amsterdam, 156 pp.
Hubach, E., 1957. Estratigrafı́a de la Sabana de Bogotá y sus alrededores. Boletı́n Geológico (Ingeominas, Bogotá) 5, 93 – 113.
Imbrie, J., et al., 1984. The orbital theory of Pleistocene climate:
support from a revised chronology of the marine 18 O
record. In: Berger, A., Imbrie, J., Hays, J.D., Kukla, G., Saltzman, B. (Eds.), Milankovitch and Climate. Reidel, Dordrecht,
pp. 269 – 305.
Kasse, C., Bohncke, S.J.P., Vandenberghe, J., 1995. Fluvial periglacial environments, climate and vegetation during the Middle
Weichselian in the Northern Netherlands with special reference
to the Hengelo Interstadial. Mededelingen-Rijks Geologische
Dienst 52, 387 – 414.
Konert, M., Vandenberghe, J., 1997. Comparison of laser grain size
analysis with pipette and sieve analysis: a solution for the underestimation of clay fraction. Sedimentology 44, 523 – 535.
Kuhry, P., 1988. Palaeobotanical-palaeoecological studies of tropical high Andean peatbog sections (Cordillera Oriental, Colombia). Dissertationes Botanicae 116, 241 pp. J. Cramer/
Borntraeger, Berlin.
Lu, H., Vandenberghe, J., An, Z., 2001. Aeolian origin and palaeoclimatic implications of the dRed ClayT (north China) as
evidenced by grain-size distribution. Journal of Quaternary
Science 16, 89 – 97.
Marchant, R., Boom, A., Hooghiemstra, H., 2002. Pollen-based
biome reconstructions for the past 450 000 yr from the Funza2 core, Colombia: comparisons with model-based vegetation
reconstructions. Palaeogeography, Palaeoclimatology, Palaeoecology 177, 29 – 45.
148
V. Torres et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 226 (2005) 127–148
Mommersteeg, H., 1998. Vegetation development and cyclic and
abrupt climatic change during the Late Quaternary. PhD Thesis,
University of Amsterdam, Amsterdam, 191 pp.
Rangel, O., 2003. El antiguo lago de la Sabana de Bogotá, su
vegetación y su flora en el tiempo. In: Bogotá, A.D., C. Conservación Internacional (Eds.), Los humedales de la Sabana de
Bogotá. Zetta Comunicadores, Bogotá, pp. 53 – 68.
Rangel, O., Aguirre, J., 1983. Comunidades acuáticas altoandinas: I.
Vegetación sumergida y de ribera en el Lago de Tota (Boyacá).
Caldasia 13, 719 – 742.
Rangel, O., Aguirre, J., 1986. Estudios ecológicos en la Cordillara
Oriental colombiana: III. La vegetación de la cuenca del Lago
de Tota (Boyacá). Caldasia 15, 263 – 312.
Scheibe, R., 1933. Observaciones casuales sobre la estructura geológica en la Cordillera Oriental. Compilación de los Estudios
Geológicos Oficiales en Colombia 1, 65 – 90.
Shackleton, N., Berger, A., Peltier, W.R., 1990. An alternative
astronomical calibration of the lower Pleistocene timescale
based on ODP Site 677. Transactions of the Royal Society of
Edinburgh. Earth Sciences 81, 251 – 261.
Sun, D., Bloemendal, J., Rea, D.K., Vandenberghe, J., Jiang, F., An,
Z., Su, R., 2002. Grain-size distribution function of polymodal
sediments in hydraulic and aeolian environments, and numerical
partitioning of the sedimentary components. Sedimentary Geology 152, 263 – 277.
Sun, D., Bloemendal, J., Rea, D.K., An, Z., Vandenberghe, J., Lu,
H., Ruixia, S., Tungsheng, L., 2004. Bimodal grain-size distribution of Chinese loess, and its palaeoclimatic implications.
Catena 55, 325 – 340.
Torres, V., 1995. Análisis paleoclimático con base en palinologı́a de
los sesenta metros superiores del pozo Ingeominas-I y su relación con los depósitos lacustres de la Sabana de Bogotá. Undergraduate Thesis, Universidad Nacional de Colombia, Bogotá,
D.C., 43 pp.
Vandenberghe, J., Lu, H., Sun, D., Van Huissteden, J., Konert, M.,
2004. The late Miocene and Pliocene climate in East Asia as
recorded by grain-size and magnetic susceptibility of the Red
Clay deposits (Chinese loess plateau). Palaeogeography Palaeoclimatology Palaeoecology 204, 239 – 255.
Van der Hammen, T., González, E., 1963. Historia de clima y
vegetación del Pleistoceno Superior y del Holoceno de la
Sabana de Bogotá. Boletı́n Geológico (Ingeominas, Bogotá)
11, 189 – 266.
Van der Hammen, T., Hooghiemstra, H., 1997. Chronostratigraphy
and correlation of Pliocene and Quaternary of Colombia. Quaternary International 40, 81 – 91.
Van der Hammen, T., Werner, J.H., Van Dommelen, H., 1973.
Palynological record of the upheaval of the Northern Andes: a
study of the Pliocene and lower Quaternary of the Colombian
Eastern Cordillera and the early evolution of its high-Andean
biota. Review of Palaeobotany and Palynology 16, 1 – 122.
Van Geel, B., Van der Hammen, T., 1973. Upper Quaternary
vegetational and climatic sequence of the Fúquene area (Eastern
Cordillera, Colombia). Palaeogeography, Palaeoclimatology,
Palaeoecology 14, 9 – 92.
Van ’t Veer, R., Hooghiemstra, H., 2000. Montane forest evolution
during the last 650 000 yr in Colombia: a multivariate approach
based on pollen record Funza-1. Journal of Quaternary Science
15, 329 – 346.
Van ’t Veer, R., Ran, E.T.H., Mommersteeg, H., Hooghiemstra, H.,
1995. Multivariate analysis of the middle and late Pleistocene
Funza pollen records of Colombia. Mededelingen-Rijks Geologische Dienst 52, 195 – 212.
Wijninga, V., 1996. Paleobotany and palynology of Neogene sediments from the high plain of Bogotá (Colombia). PhD Thesis,
University of Amsterdam, Amsterdam, 370 pp.
Wijninga, V., Rangel, O., Cleef, A.M., 1989. Botanical ecology and
conservation of the Laguna Herrera (Sabana de Bogotá). Caldasia 16, 23 – 40.