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ThefinalphaseoftropicallowlandconditionsintheaxialzoneoftheEasternCordilleraofColombia:Evidencefromthreepalynologicalrecords

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The final phase of tropical lowland conditions in the axial zone of the EasternCordillera of Colombia: Evidence from three palynological records

D. Ochoa a,b,*, C. Hoorn c, C. Jaramillo a, G. Bayona d, M. Parra e, F. De la Parra f

a Smithsonian Tropical Research Institute, P.O. Box 0843, Balboa, 03092 Ancon, PanamabDepartment of Biological Sciences, East Tennessee State University e ETSU, Johnson City, TN 37614-14850, USAc Paleoecology and Landscape Ecology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, NetherlandsdCorporación Geológica ARES, Calle 44A #53-96, Bogotá, ColombiaeDepartment of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712, USAf Instituto Colombiano del Petróleo - Ecopetrol, Km 7 vía Piedecuesta-Bucaramanga, Colombia

a r t i c l e i n f o

Article history:Received 10 May 2011Accepted 2 April 2012

Keywords:Eastern CordilleraSanta Teresa FormationUsme FormationConcentración FormationAndean orogenyLate Eocene-Early Miocene

a b s t r a c t

Deformation of the Eastern Cordillera, as a double-verging thrust belt that separates the MagdalenaValley from the Llanos Basin, is a defining moment in the history of the northern Andes in South America.Here we examine the age and depositional setting of the youngest stratigraphic unit in three sectors ofthe Eastern Cordillera: (i) the Santa Teresa Formation (western flank), (ii) the Usme Formation (southerncentral axis), and (iii) the Concentración Formation (northeastern central axis). These units weredeposited prior to the main Neogene deformation events. They represent the last preserved record oflowland conditions in the Eastern Cordillera, and they are coeval with a thick syn-orogenic depositionreported in the Llanos Basin and Magdalena Valley. Based on palynological data, we conclude that theupper Usme Formation was deposited during the Bartonian-earliest Rupelian? (Late Eocene-earliestOligocene?); the Concentración Formation was deposited during the Late Lutetian-Early Rupelian(Middle Eocene to Early Oligocene), and the upper Santa Teresa Formation was accumulated during theBurdigalian (Early Miocene). These ages, together with considerations on maximum post-depositionalburial, provide important time differences for the age of initial uplift and exhumation along the axialzone and western foothills of the Eastern Cordillera. The switch from sediment accumulation to erosionin the southern axial zone of the Eastern Cordillera occurred during the Rupelian-Early Chattian(Oligocene, ca 30 to ca 26 Ma), and in the northeastern axial zone occurred prior to the latest Chattian-Aquitanian (latest Oligocene-Early Miocene ca 23 Ma). In contrast, in the western flank, the switchoccurred during the Tortonian (Late Miocene, ca 10 Ma). In addition, we detected a marine transgressionaffecting the Usme and Concentración formations during the Late Eocene; coeval marine transgressionhas been also documented in the Central Llanos Foothills and Llanos Basin, as evidenced by the similarityin floras, but not in the western foothills. Our dataset supports previous sedimentological, geochemicaland thermochronological works, which indicated that (i) deformation in the Eastern Cordillera wasa diachronous process, (ii) the sedimentation along the axial zone stopped first in the south and then inthe north during the Oligocene, (iii) depositional systems of the axial zone and central Llanos Foothillskept partly connected at least until the Late Eocene, and (iv) Miocene strata were only recorded inadjacent foothills as well as the Magdalena and Llanos basins.

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1. Introduction

The northern Andes Mountains are the result of a complexinteraction between the continental South American plate and theoceanic Caribbean andNazca plates (Fig.1). One consequence of thismultistage orogeny was the asynchronous building of threedifferent mountain belts -the Western, Central, and EasternCordilleras- throughout the Mesozoic and Cenozoic (Barrero, 1979;Etayo et al., 1983; Villamil, 1999). Deformation of the Eastern

* Corresponding author. Smithsonian Tropical Research Institute, P.O. Box 0843,Balboa, 03092 Ancon, Panama.

E-mail addresses: dianita.ochoa@gmail.com, ochoalozano@goldmail.etsu.edu(D. Ochoa), carina.hoorn@milne.cc (C. Hoorn), jaramilloc@si.edu (C. Jaramillo),gbayona@cgares.org (G. Bayona), mparra@cgares.org (M. Parra), felipe.delaparra@ecopetrol.com.co (F. De la Parra).

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Fig. 1. Geographical location of studied sections. Modified after Pardo-Trujillo (2004). CC ¼ Central Cordillera, WC ¼ Western Cordillera, UMV ¼ Upper Magdalena Valley,SNSM ¼ Sierra Nevada de Santa Marta, SNCo ¼ Sierra Nevada del Cocuy, CatB ¼ Catatumbo Basin.

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Cordillera (EC), as a double-verging orogen with intermontanebasins along the axial zone (Cooper et al., 1995; Cortés et al., 2006),was of particular significance in the geological history of northernSouth America as itmodified river drainages (Guerrero,1997; Hoornet al., 1995, 2010), promoted vertical surface uplift in the last3e5m.y. (Gregory-Wodzicki, 2000; Mora et al., 2008b), and creatednew habitats, such as páramos and cloud forests in the axial zone ofthe EC (Hooghiemstra, 1984, 1988; Van der Hammen et al., 1973).Tectono-sedimentological, geodynamic and thermochronologicalstudies have shown that the Eastern Cordillera in the ColombianAndes was already tectonically active during the Early Paleocene(Bayona et al., 2008; Parra et al., 2012) and the Late Eocene-EarlyOligocene (Bande et al., 2012; Bayona et al., 2008; Gómez et al.,2005, 2003; Horton et al., 2010b; Mora et al., 2010a; Nie et al.,2010; Parra et al., 2009a, 2009b; Saylor et al., 2011; Toro et al.,2004). During the Late Neogene, the tectonic activity in theEastern Andes rapidly increased (Duque-Caro, 1990; Helmens andVan der Hammen, 1994; Hooghiemstra and Van der Hammen,1998; Hoorn et al., 1987; Mora et al., 2010b; Shephard et al., 2010;Taboada et al., 2000), generating amajor exhumationpulse of the ECin the last w7 m.y. (Bayona et al., 2008; Cortés et al., 2006; Moraet al., 2010b). These pulses led to changes in regional climate(Ehlers and Poulsen, 2009; Insel et al., 2009; Sepulchre et al., 2009)and the sedimentary regimes in the adjacent lowlands whichresulted in the establishment and evolution of the Amazon River(Figueiredo et al., 2009, 2010; Hoorn,1994; Hoorn et al., 1995, 2010;Hoorn and Wesselingh, 2010; Shephard et al., 2010) and increasedbiodiversity in western Amazonia (Hoorn et al., 2010).

Both the onset of double-verging deformation of the EC andconsequent isolation of the Magdalena River Valley from the Llanosregion are critical to the development of the northern Andes. Inorder to understand the final phase of the sedimentationwithin theEC, we have dated the youngest sediments preserved in threedifferent synclines located (1) along the western flank of the EC(Santa Teresa Formation in the Guaduas Syncline), (2) in thesouthern axial zone of the EC (Usme Formation in the UsmeSyncline, Bogotá High Plain), and (3) in the northeastern axial zoneof the EC (Concentración Formation in the Floresta Syncline, foot-wall of the Soapaga Fault) (Fig. 1). In addition, we have providedtemporal estimates of the switch from burial to exhumationthrough the assessment of the magnitude of post-depositionalburial based on recently published paleothermal and thermo-chronometric data. Finally, we have reviewed several depositionaland kinematic models to evaluate the degree of connectivitybetween the basins during the Late Eocene to Early Miocene.

2. Lithostratigraphic setting

The Late Eocene to Miocene evolution of the EC is recorded inthree different large synclines located across the EC (Table 1). Theyoungest sediments, which are preserved at the core of eachsyncline, also represent the youngest sediments preserved in theEC, other than the Pliocene lake and alluvial sediments from theBogota High plain (Helmens, 1990; Helmens and Van der Hammen,1994; Hooghiemstra and Van der Hammen, 1998; Hoorn et al.,1987). All stratigraphic sections were measured near the areawhere the type section of each formation was proposed (De Porta,1974). In the western flank, we studied the youngest sediments ofthe Guaduas Syncline, represented by the Santa Teresa Formation(De Porta, 1966; De Porta, 1974). In the southern axial zone, weexamined the youngest strata of the Usme Syncline, represented bythe Usme Formation (De Porta, 1974; Hoorn et al., 1987). Lastly, inthe northeastern axial zone, we studied the youngest strata of theFloresta Syncline, represented by the Concentración Formation(Rodríguez and Solano, 2000; Ulloa et al., 2001) (Fig. 1).

The fossil-rich Santa Teresa Formation was defined by De Porta(1966) and originally thought to be the Early-Middle Miocene LaCira Formation (Raasveldt and Carvajal, 1957; Van der Hammen,1958), which outcrops in the northern Middle Magdalena ValleyBasin. However, De Porta (1966) suggested a different nomination,assigning the Santa Teresa name for the rocks outcropping in thearea of the Guaduas Syncline. The formation conformably overliesthe San Juan de Río Seco Formation and is w475 m thick along theBogotá-Cambao road. It has a lithofacies distinctive of quietlagoonal settings (De Porta, 1966), which is partially confirmed bysome forms of sapropelic organic matter (alginite and liptode-trinite), reported in the upper half of the unit (Gómez, 2001). Acostaand Ulloa (2001) report lithofacies representative of shallow,freshwater environments with channels filled with conglomeraticand sandy lithologies, presence of several coal beds, abundant leafimpressions, fish bones, gastropods and bivalves along the BalúCreek in Cundinamarca. Pilsbry and Olsson (1936), in contrast,suggested occasional presence of salty waters based on somehorizons with gastropods and mollusks favoring brackish waters(Corbula). The age of the formation is uncertain although Oligocene(De Porta and De Porta, 1962), Late Oligocene (Acosta and Ulloa,2001), Oligocene-Early Miocene? (De Porta, 1966), and EarlyMiocene ages (Nuttall, 1990) have been suggested based on mala-cological and palynological data. The formation broadly correlateswith the Colorado and La Cira formations in the Middle MagdalenaValley Basin (De Porta, 1974; Van der Hammen, 1958).

The Usme Formation was proposed by Hubach (1957) andJulivert (1963), it overlies the Regadera Formation. The type ofcontact is variable, from unconformable in the eastern flank of theUsme Syncline (Hoorn et al., 1987; Julivert, 1963) to conformable inthe western flank (Julivert, 1963; Montoya and Reyes, 2005). TheUsme Formation is unconformably overlain by Late Miocene? -Pliocene alluvial, gravity-flow material and lacustrine deposits,corresponding to the Marichuela Formation (De Porta, 1974; DePorta, 2003; Helmens, 1990; Helmens and Van der Hammen,1994; Hoorn et al., 1987; Roddaz et al., 2009; Toro et al., 2003).The Usme Formation is w365 m thick and has been traditionallysubdivided into two members (Hoorn et al., 1987; Julivert, 1963).The lower member consists dominantly of dark brown and gray-colored claystones, siltstones, and shales. Some dark gray silt-stones beds are intercalated with thin coal layers and abundantplant remains. A general upward-coarsening trend in grain size isevident in the lower member. Towards the upper part of thismember, some very fine to fine quartzitic sandstones with cross-stratification are interbedded with bioturbated shales and silt-stones levels (Hoorn et al., 1987; Montoya and Reyes, 2005). Thelower member has been interpreted as coastal plain depositsincised by subtidal channels (Hoorn et al., 1987). The uppermember of the Usme Formation is dominated by multicoloredsiltstones and shales, intercalated with yellowish massive to cross-bedded sandstones varying from coarse sand to conglomeraticlithologies (Hoorn et al., 1987). Towards the top of the section,several coal and lignite layers with abundant plant material arefound. The upper member is interpreted as the product of deltaic tointertidal settings, with sand bars, and interdigitated and

Table 1Location of selected sedimentary sections.

Formation Syncline Regional location Coordinates Samples

Latitude Longitude Analyzed

Santa TeresaFm.

Guaduas Middle MagdalenaValley

4.86�N 74.63�W 9

Usme Fm. Usme Bogotá High Plain 4.52�N 74.15�W 16Concentración

Fm.Floresta Paz del Río, Boyacá 6.03�N 72.76�W 16

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abandoned channels (Hoorn et al., 1987). The formation has beendated by palynological analysis as Late Eocene to Early Oligocene(Hoorn et al., 1987) or Middle Eocene to Middle Oligocene (Van derHammen, 1957); whereas as Middle to Late Oligocene based on thepresence of Globorotalia fohsi andina (Bürgl, 1955). The UsmeFormation has been correlated with the Concentración Formationin the Floresta Basin (De Porta, 1974; Van der Hammen and Parada,1958; Villamil, 1999) and the Upper Mirador Formation and LowerCarbonera C8 member in the Foothills and Llanos basins (Cooperet al., 1995; Pulham et al., 1997). The Upper Mirador consists ofdark shales interbedded with fine to coarse sandstones, and theLower Carbonera is composed of tabular sandstone interbeddedwith dark gray mudstone, and flaser and lenticular lamination (DePorta, 1974; Parra et al., 2009a). These lateral differences inlithology have been interpreted as facies changes between fluvialand marine-influenced conditions (Cooper et al., 1995; Pulhamet al., 1997; Roddaz et al., 2009; Saylor et al., 2011).

The Concentración Formation was proposed by Alvarado andSarmiento (1944) and conformably overlies the Picacho Forma-tion (Rodríguez and Solano, 2000). It isw1 km thick and composedof an upward-coarsening sequence of laminated mudstones inter-bedded with sandstones (Saylor et al., 2011). Oolitic ironstones,plant fragments and bioturbation are common throughout thesection (Saylor et al., 2011). The sedimentary sequence is inter-preted as having formed in a coastal plain environment withlagoonal to partially closed estuarine conditions (Saylor et al., 2011;Villamil, 1999). Oolitic ironstone up to 3 m thick, which iscommercially mined, occurs towards the base of the unit(Kimberley, 1980; Saylor et al., 2011; Van Houten, 1967). Villamil(1999) interpreted these oolitic layers as evidence of a LateEocene regional seaway that flooded northern South America.Based on palynological data, the formation has been dated asMiddle Eocene to Late Oligocene (Hubach, 1957; Van der Hammen,1957). Deposition of the Concentración Formation is consideredcoeval with the active stage of the Soapaga Fault system, whichaffected only the northern axial zone of the cordillera (Saylor et al.,2011). The unit correlates with the Usme Formation in the BogotáHigh Plain area (De Porta, 1974; Van der Hammen and Parada,1958), with the Carbonera and León formations in the CatatumboBasin (De Porta, 1974; Van der Hammen, 1958), and with the UpperMirador and Lower Carbonera formations in the Foothills and Lla-nos basins (Cazier et al., 1995; Cooper et al., 1995; Santos et al.,2008; Villamil, 1999) (Fig. 1).

3. Methods

A total of 41 samples from the three formations (Table 1) wereprocessed for palynological analysis following standard procedures(Traverse, 2007). All samples were digested by using 10% HCl and40% HF. Each sample was sieved using 10 mm and 100 mm meshes;finally, permanent montages were prepared. Light microscopy wasused to examine the palynological content and at least 100 grainswere counted per slide. Morphological features were comparedwith descriptions and illustrations from various resources (Dueñas,1980; Germeraad et al., 1968; Gonzalez, 1967; Hoorn et al., 1987;Jaramillo et al., 2010; Jaramillo et al., 2007; Jaramillo and Dilcher,2001; Jaramillo et al., 2011; Leidelmeyer, 1966; Lorente, 1986;Muller et al., 1987; Van der Hammen, 1956; Van der Hammen andGarcía de Mutis, 1966) and taxonomical nomenclature followedJaramillo and Dilcher (2001).

The sections were dated using a maximum likelihood estima-tion based on the palynological zonation proposed by Jaramilloet al. (2011), which has been time-calibrated using carbonisotopes, radiometric dating, foraminifera and magnetic-stratigraphy data (Fig. 2). Maximum likelihood analysis follows

the procedure of Punyasena et al. (2012) (Appendix 1). Additionally,a Marine Influence Index (MI) was calculated using the ratioproposed by Santos et al. (2008), in order to estimate the relationbetween marine and terrestrial palynomorphs. The index wasestimated for each sample asMI¼M/T, whereM is the total numberof marine palynomorphs and T is the total number of paly-nomorphs counted per sample (Rull, 2002; Santos et al., 2008). Allanalyses were conducted using standard libraries from the programR (R Development Core Team, 2009), which is a free-software,developed by several contributors and administered by the RFoundation for Statistical Computing (http://www.R-project.org).In addition, the Stratigraph package was used to produce thepalynostratigraphic range charts (Green et al., 2010).

4. Palynological results

4.1. Santa Teresa Formation

Palynological matter was recovered only from the upper 266 mof the Santa Teresa Formation. The palynoflora includes a largeabundance of ferns spores (e.g. Psilatriletes and Laevigatosporites)and palms (Mauritiidites). Fungal remains are common throughoutthe entire section, also a 78.5 m thick interval with abundantPediastrum and Botryococcus algae was observed (from 549.74 m to628.24 m) (Fig. 3). Neither mangrove elements nor marine paly-nomorphs were observed (Fig. 3). The most abundant paly-nomorphs included Mauritiidites franciscoi, Perisyncolporitespokornyi, Magnaperiporites spinosus, Rhoipites guianensis, Psilamo-nocolpites, Laevigatosporites, Polypodiisporites and Psilatriletesgroups (Appendices 2 and 3).

The co-occurrence of Magnastriatites grandiosus (First Appear-ance Datum [FAD] at 451.2 m), M. spinosus (FAD at 456.79 m),Concavissimisporites fossulatus (FAD at 470.7 m), and Bom-bacacidites muinaneorum (FAD at 468.71 m) (Fig. 4), as well as theoverall abundance of other key taxa, such as Bombacacidites brevis,Echiperiporites akanthos, Mauritiidites franciscoi, Perisyncolporitespokornyi, Ranunculacidites operculatus, Retitrescolpites? irregularis,Spirosyncolpites spiralis, Striatriletes saccolomoides, Tetracolpor-opollenites maculosus and Tetracolporopollenites transversalis, indi-cates that this palynoflora corresponds to the palynological zonesT-12 and T-13. These two zones have been dated as 16.1e23 Ma,corresponding to the Aquitanian-Burdigalian, Miocene (Jaramilloet al., 2011). This interpretation is supported by maximum likeli-hood analysis (Fig. 5), which indicates a high probability of corre-lation with the upper part of palynological zone T-12 Horniellalunarensis and zone T-13 Echitricolporites maristellae (Burdigalian,19e16 Ma).

4.2. Usme Formation

Good pollen recovery was found for most of the section, exceptfor the lower 116 m and the uppermost 60 m, where no pollen wasfound. The palynoflora is characterized by high abundances of fernspores (e.g. Polypodiisporites and Laevigatosporites) and palms (e.g.Mauritiidites) (Appendices 4 and 5). Four levels contain dinofla-gellate cysts and acritarchs (2140 m, 2141 m, 2152 m, and 2258 m).Levels located towards the base of the upper member exhibit thehighest Marine Influence Index values (at 2140 m, 2141 m and2152 m, MI ¼ 0.05, 0.09 and 0.029, respectively), whereas marineinfluence was minimal at the top of the section, at 2258 m(MI ¼ 0.012) (Fig. 3). Colonies of Pediastrum sp. were commonbetween 2140 m and 2142.6 m, and high frequencies of mangroveelements (Rhizophoraceae and Pellicieraceae) occurred between2258 m and 2299 m (mean 5.6%) (Fig. 3).

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Fig. 2. Palynological zonation proposed for the Cenozoic of the Llanos and Llanos Foothills by Jaramillo et al. (2011) and Muller et al. (1987). Geologic time scale after Gradstein et al.(2004).

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The most common angiosperm taxa recovered include M. fran-ciscoi, Echitriporites trianguliformis orbicularis, Longapertites prox-apertitoides var. proxapertitoides, P. pokornyi, R. guianensis, T.maculosus, T. transversalis, and the Psilamonocolpites and Reti-tricolporites groups.

Cicatricosisporites dorogensis and the Laevigatosporites, Poly-podiisporites, and Psilatriletes groups dominated pteridophytespores composition. Other important taxa recovered include Are-cipites regio, Cricotriporites guianensis, E. akanthos, Echitetracolpites?tenuiexinatus, Foveotriporites hammenii, Lanagiopollis crassa,Monoporopollenites annulatus, Poloretitricolpites absolutus, Spi-rosyncolpites spiralis, Syncolporites marginatus and Zonocostitesramonae (Appendices 4 and 5). Echitriporites trianguliformis orbi-cularis occurs throughout the section, except for the uppermostsample, at 2354 m. A single occurrence of C. fossulatus was alsofound at 2254 m (Fig. 4).

The frequent occurrence of Echitriporites trianguliformis orbicu-laris, along with the Last Appearance Datum [LAD] of A. regio (at2254 m), S. marginatus (at 2294 m) and Echitetracolpites? tenuiex-inatus (at 2299 m), the FAD of E.chiperiporites akanthos (at 2254 m),and the presence of P. absolutus (single occurrence at 2267 m)(Fig. 4) indicates that up to meter 2299 the palynoflora belongs topalynological zone T-07 Echitriporites trianguliformis orbicularis,

dated as Late Eocene (38e33.9 Ma) (Jaramillo et al., 2009, 2011)(Fig. 2). This dating is also supported by the maximum likelihoodanalysis, which indicates a high probability of correlationwith zoneT-07 Echitriporites trianguliformis orbicularis for the entire section,except for the last sample (Fig. 5).

Only one sample with poor recovery (2354 m) was obtainedfrom the uppermost 60m of section. Among other taxa, F. hammeniiwas recovered in this sample. The LAD of F. hammenii is consideredas an important biostratigraphic event and was estimated at33.24 Ma (Jaramillo et al., 2011). Based on the presence of thistaxon, we consider the upper sediments to be no younger thanearly Oligocene (earliest Rupelian, ca 33 Ma). In consequence, wesuggest a Bartonian-earliest Rupelian? age (ca 38 to 33 Ma) for theupper-lower to upper Usme Formation.

4.3. Concentración Formation

Good pollen recovery was obtained in almost the entiresequence except for the upper part of the section, where palyno-logical recovery was poor (1211 me1440 m) (Appendices 6 and 7).The palynofloral assemblage is dominated by fern spores (C. dor-ogensis, Laevigatosporites, M. grandiosus, and Polypodiisporites) andangiosperms including M. franciscoi, Psilamonocolpites medius, T.

Fig. 3. Relative abundances of terrestrial plants, marine and fresh waters elements present in each unit. Marine Influence (MI) Index values ranges from 0 (fully terrestrial) to 1(fully marine). Palynological zones after Jaramillo et al. (2011). Vertical scales vary in each section.

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maculosus, T. transversalis, and L. crassa. Three peaks of mangroveabundance (L. crassa, a Pellicieraceae) occur throughout the sectionat 40.49 m (23.7% of the palynoflora), 559.99 m (11.5%), andbetween 774.49 m and 832 m (47%) (Fig. 3). Three intervals withincreased abundances of freshwater algae were found at 40.49 m(0.7%), from 360 m to 391.49 m (0.6%) and from 715.49 m to751.49 m (1.5%). Four intervals displaying high MI values werefound at 40.49 m (MI ¼ 0.13), at 560 m (MI ¼ 0.019), from 751.49 mto 774.5 m (MI ¼ 0.02), and from 797.5 m to 832.49 m (MI ¼ 0.15)(Fig. 3).

The palynoflora indicates the presence of four palynologicalzones as follows: zone T-06 Spinizonocolpites grandis from the baseto 116.9 m; zone T-07 Echitriporites trianguliformis orbicularis from116.9 m to 735.5 m; zones T-08 Nothofagidites huertasii to T-09Foveotricolporites etayoi from 735.5 m to 1210.5 m.

Palynological zone T-06 is identified by the LAD of S. grandis (at116.9 m) (Fig. 4). In addition, it is supported by the co-occurrence ofC. dorogensis, Laevigatosporites catanejensis and R. guianensis, all ofwhich have their FADs at 40.49 m. Palynological zone T-07 is indi-cated by the LADs of Echitriporites trianguliformis orbicularis (at735.5 m), Proxapertites magnus (at 391.4 m), and Racemonocolpitesfacilis (at 371.9 m), and by FADs of Striatriletes saccolomoides (at559.9 m) and Polypodiisporites usmensis (at 391.49 m) (Fig. 4). Theoccurrence of Echitetracolpites? tenuiexinatus (at 334.49 m) alsosupports this zone. Finally, zones T-08N. huertasii toT-09 F etayoi arenoted by the FAD of M. grandiosus (at 1101.0 m), and the LAD ofSpinizonocolpites echinatus (at 797.49 m) (Fig. 4). Zone T-09 is alsosupported by high abundances of C. dorogensis, occurring towardsthe top of the section (see Appendices 6 and 7). These four palyno-logical zones, also supported by the maximum likelihood analysis(Fig. 5), indicate a Lutetian-Early Rupelian (Middle Eocene-EarlyOligocene, ca 39 to 31.5 Ma) age for the Concentración Formation.

5. Discussion of palynological data

5.1. Age

We found that the upper sediments of the Santa TeresaFormation (corresponding to the uppermost 266 m) have a highprobability of belonging to the upper part of palynological zone T-12 H. lunarensis and zone T-13 E. maristellae (Burdigalian, EarlyMiocene, 19e16 Ma) (Figs. 4 and 5). Earlier stratigraphic, malaco-logical and palynological studies considered the formation ashaving accumulated during the Oligocene (De Porta and De Porta,1962), Late Oligocene (Acosta and Ulloa, 2001), Oligocene to EarlyMiocene? (De Porta, 1966) or Early Miocene (Nuttall, 1990).

De Porta and De Porta (1962) studied the palynological associ-ations within the section and reported occurrences of Poly-podiisporites usmensis, Psilamonocolpites, Mauritiidites andPsilatriletes groups, and by using the relative abundance of eachgroup, they correlated the section with the Oligocene zonesproposed by Van der Hammen (1958). Van der Hammen’s zones arebased on abundance peaks of broad categories that representmodifications in the vegetation due to regional climatic changes.Thus, each abundance cycle had a certain chronostratigraphic valueaccording to the climate variation. This methodology has beendescribed as inappropriate for biostratigraphic purposes (Jaramilloet al., 2011; Moore et al., 1991), because it depends on factors suchas environmental settings during deposition, type of sedimentssampled, and it is also greatly affected by the “closed sum” math-ematical effect (Kovach and Batten, 1994; Moore et al., 1991).Furthermore, Van der Hammen’s approach did not use an externalage-dataset for calibration.

De Porta (1966) suggested an Oligocene to Early Miocene? age.He established the Oligocene age by using the stratigraphic position

Fig. 4. Palynological zones established for each section. Arrows indicated the occurrence of key taxa used to define the palynological zones. Note Santa Teresa Formation includesfrom the upper part of zone T-12 to zone T-13, Usme Formation only includes zone T-07 and Concentración Formation includes from zone T-06 to T-09. Vertical scales vary in eachsection.

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of the section and previous palynological data as discussed above(De Porta and De Porta, 1962), whereas the Early Miocene? age wasbased on the mollusk association Anodontites laciranus, Hemisinuswaringi and Diplodon opocitonis described by Anderson (1929).

Likewise, Nuttall (1990) assigned an Early Miocene age afterreviewing the malacological material collected and described byAnderson (1929). Although both studies assigned an Early Mioceneage to the fauna, they also discussed extensively the uncertainty ofthe exact stratigraphic position of this association within the Gua-duas Syncline. Furthermore, Nuttall (1990) pointed out that there isno precise information indicating that the mollusk fauna actuallybelongs to any level from theGuaduas structure. He also argued thatButler (1939) tentatively located the fauna close to the core of theGuaduas Syncline, and as a result, the mollusk assemblage has beenplaced at the upper part of the Santa Teresa Formation. In addition tothe stratigraphic uncertainty, De Porta (1966) signaled that thecorrelation with the Miocene La Cira Formation based on themollusk faunawas biased by the high frequency of endemic specieswithin the Santa Teresa Formation. Consequently, De Porta (1966)and Nuttall (1990) concluded that although the fauna probablycould suggest an Early Miocene age, the certainty of the dating wasvery low. The new palynological data presented herein supportsa Burdigalian, Miocene (19e16 Ma) age for the upper sedimentsfrom the Santa Teresa Formation (Figs. 4 and 5). However, the lowerpart of the Santa Teresa still needs to be dated.

The palynofloral assemblage recovered from upper part of thelower Usme Formation and lower part of the upper Usme Forma-tion corresponds to palynological zone T-07 Echitriporites triangu-liformis orbicularis of Jaramillo et al. (2011) (Figs. 4 and 5), which isdated as Late Bartonian-Priabonian, Eocene (38e33.9 Ma) (Fig. 2).The uppermost 60 m of the section did not provide conclusiveevidence supporting zone T-07, and it contains F hammenii, a taxonwhose extinction is estimated at 33.24 Ma (Jaramillo et al., 2011).Therefore we consider the upper-lower and upper Usme Formationas Bartonian to earliest? Rupelian (Late Eocene to earliest? Oligo-cene, 38e33 Ma) in age.

Van der Hammen (1957) dated the Usme section as MiddleEocene to Middle Oligocene, based on the stratigraphic position ofthe unit and occurrence peaks of Striatriletes susannae, a juniorsynonym of C. dorogensis (Potonie and Johann, 1933). As discussedbefore, age dating based on vegetation cycles may be biasedbecause it may signal ecological settings rather than chronologicalevents. Hoorn et al. (1987), following the palynological zonationproposed by Muller et al. (1987), designated a Late Eocene-EarlyOligocene age by correlation with the Echiperiporites estelae andMagnastriatites-Cicatricosisporites Zones (see Fig. 2). The latter zonewas supported by the co-occurrence of M. grandiosus and C dor-ogensis in the uppermost part of the Usme Formation. We carefullyreanalyzed the same palynological slides examined by Hoorn et al.(1987) but never detected the presence of M. grandiosus. Moreover,we did not findM. grandiosus in additional samples from the rest ofthe section. It is possible that large specimens of C. dorogensissometimes can be confused with small specimens of M. grandiosus,and this could be the case in Hoorn et al.’s (1987) work.

The palynoflora recovered from the Concentración Formationranges from the upper T-06 S. grandis to T-09 F. etayoi of Jaramilloet al. (2011) (Figs. 4 and 5). Thus, we interpret the lower 1210 mof the section as having accumulated during the Late Lutetian toEarly Rupelian (latest Middle Eocene to early Early Oligocene, 39 to31.5 Ma). Because we did not recover pollen from the upperw240 m, we were unable to directly establish the depositional agefor this segment. Nevertheless, we estimate the approximate age atthe top of the formation as Rupelian (ca 31.5 Ma), by assumingconstant sedimentation rates in the upper 240 m, and by using theFAD of M. grandiosuswithin the section (1101.0 m) as age reference(ca 33.67 Ma, according to Jaramillo et al., 2011).

Van der Hammen (1957) dated the Concentración Formation asextending from the Middle Eocene to the earliest Late Oligocenebased on vegetational abundance peaks. As in the case of the Usme

Fig. 5. Stratigraphic age estimates per section calculated using the probabilisticMaximum Likelihood approach based on the taxa abundance. Normalized likelihoodvalues are represented by color with higher and lower likelihood values symbolized bygreen and blue, respectively. Inferior axis showing geologic time (Ma), vertical axisrepresenting depth and superior axis marking the palynological zones proposed byJaramillo et al. (2011). Vertical scales vary in each section. Samples are represented byyellow bars.

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Formation, he based the Oligocene age mainly on high occurrencesof Striatriletes susannae, a junior synonym of C. dorogensis (Potonieand Johann, 1933). Van der Hammen confirmed this age by usinga coal seam from the Usme Formation, which was previously datedas Middle Oligocene also on the basis of a peak in C. dorogensis (Vander Hammen,1957). Given that non-independent datawere used toconstrain the chronostratigraphic frame in both the Usme andConcentración formations, the dating may have relied on circularreasoning. Nevertheless, the age proposed by Van der Hammen issimilar to the age proposed here.

The dating established herein implies a revision of the tradi-tional chronostratigraphic correlations for the Eastern Cordillera. Inparticular, the Usme and Concentración formations have generallybeen considered as coeval units (Gómez et al., 2005; Van derHammen, 1957, 1958), deposited during the Middle Eocene-Middle Oligocene. As shown here, the upper boundaries of thetwo formations are not coeval (see Figs. 4 and 5). The uppermostpart of the Usme Formation is dated as Bartonian-earliest Rupelian?(33.9 to ca 33 Ma), whereas the youngest dated strata of the Con-centración Formation are at least Early Rupelian (ca 31.5 Ma).Nevertheless, lithological features in both formations indicate thatthey share similar depositional settings (Hubach, 1957) and periodsof marine influence (see Section 8).

5.2. Paleoenvironments

The pollen association from all three sites is indicative oflowland regions (e.g. Mauritiidites, P. pokornyi, L. crassa, R. guia-nensis, Spirosyncolpites spiralis). No pollen or spore species typicalof Andean or páramo vegetation (Hooghiemstra et al., 1993;Hooghiemstra and Ran, 1994; Van der Hammen et al., 1973;Wijninga, 1996) were found.

The palynofloral assemblage recovered from the Santa TeresaFormation is typical for wetlands and swampy areas and, mostlyrestricted to freshwaters conditions, as neither mangrove elementsnor marine palynomorphs were found. Furthermore, a freshwater(lacustrine) interval was also inferred from high abundances ofboth Botryococcus sp. and Pediastrum sp. (549.74 me628.24 m)(Fig. 3). We agree with the conclusions of previous works that theupper part of this unit was formed in a lacustrine setting (Acostaand Ulloa, 2001; De Porta, 1966). De Porta (1966) suggested thatthe sedimentary sequence was formed in a lagoonal setting butwith occasional connections to the sea based on the presence ofbrackish-water mollusks and gastropods reported by Anderson(1929). However, Nuttall (1990) revisited the fauna described byAnderson, and he concluded that neither of the two reviewedgenera ascribed to the section (Pachydon and Verena) is a definitiveindicator of brackish waters. Moreover, living species from thegenus Verena are salinity intolerant and therefore restricted tofreshwater environments (Nuttall, 1990). Consequently, there is noevidence supporting a connection to the sea.

Similar lacustrine conditions have been reported for the upperMugrosa (Middle Magdalena Valley) and Barzalosa formations(Upper Magdalena Valley). The upper part of the Early MioceneMugrosa Formation (Caballero et al., 2010; Hubach, 1957) is a thicklacustrine deposit (Nuttall, 1990), which might correlate with thelacustrine levels of Santa Teresa. Likewise, the Barzalosa Formation(De Porta, 1966) consists of multicolored mudstones interbeddedwith some conglomeratic and gravel levels and contains thicklacustrine deposits characterized by blue and green claystones ofEarly Miocene age (De Porta, 1966). On the other side of the EC, theEarly Miocene C2 member of the Carbonera Formation wascontinuously deposited in the easternmost flank of the EC (Parraet al., 2009a) and in the Llanos Basin, east of the EC (Cooper et al.,1995). The C2 accumulated in marine-influenced coastal plain

environments (Cooper et al., 1995) and contains both marinepalynomorphs and mollusks (Gómez et al., 2009; Jaramillo et al.,2011). The pattern suggests that Santa Teresa, Barzalosa and theupper Mugrosa formations were part of a large lacustrine systemalong the Magdalena River Basin, whereas the Llanos Basin wasalready separated from the Magdalena Basin and part of a differentdrainage basin. This conclusion is also supported by the detritalzircon analysis of Horton et al. (2010b), who found a significantabsence of MesozoiceCenozoic zircons in Middle and Late Miocenesamples from the Guayabo and Corneta formations (Llanos Basin);this was attributable to the effective topographic barrier created bythe EC by the Middle Miocene, which separated the CentralCordillera source area from the Llanos Basin. Our data suggest thatthis barrier was already present by the Early Miocene. However,given that the Santa Teresa palynological record contains abundantfloristic elements from lowland regions and none from Andean orpáramo vegetation, this topographic barrier apparently did notreach elevations higher than 1000 m by the Early Miocene.

The Usme palynoflora, with common presence of mangrove andmarine elements (Fig. 3) together with high abundances of lowlandterrestrial floras, suggests that accumulation took place in coastalplains with tidal influence, as had been suggested herein andpreviously (Hoorn et al., 1987; Montoya and Reyes, 2005). A well-defined marine flooding event in the middle part of the forma-tion (2130 me2160 m) is indicated by the MI index (Fig. 3). Asimilar marine flooding event in the Late Eocene has already beenidentified in the Central Llanos and Llanos Foothills basins (Santoset al., 2008). The presence of Late Campanian-Maastrichtian paly-nomorphs (Buttinia andreevi and Syndemicolpites typicus) withinthe recovered palynoflora (Appendices 4 and 5) indicates an activeerosional recycling from Campanian-Maastrichtian rocks (Guada-lupe-Guaduas formations?).

The palynoflora of the Concentración Formation is similar tothat of the Usme Formation having moderate abundances of bothmangrove and marine elements (Fig. 3), together with high abun-dances of terrestrial lowland floras. This corroborates previoussuggestions that accumulation took place in coastal plains withtidal influence (Saylor et al., 2011; Villamil, 1999). There are threedistinctive marine intervals (Fig. 3). The first event occurs withinzone T-06 (40.49 m) during the Middle Eocene (Bartonian), thesecond within zone T-07 (560 m) during the Late Eocene (Priabo-nian) and third within the uppermost T-07 to the lower T-08 zone(751.49 me832.49 m), during the latest Eocene to Early Oligocene(latest Priabonian to Early Rupelian) (Fig. 3). A Middle Eocenemarine event that has been identified in the central Llanos Foothills(Jaramillo and Dilcher, 2001), in the middle of the MiradorFormation, can be correlated with the first marine interval(40.49 m). Another flooding event during the Late Eocene can becorrelated with the event observed in Usme, which is registeredthroughout the Llanos and Llanos Foothills basins (Santos et al.,2008). Our results agree with previous MI values reported bySantos et al. (2008) for the Paz del Río area (MI < 0.02) (Fig. 3).Santos et al. (2008) proposed that a NWeSE marine incursionentered via the Lower Magdalena Valley and inundated the basinup to the Central Llanos Foothills. In this way, marginal marine andestuarine settings were established along the northern axial zoneof the Eastern Cordillera. Our results support their interpretation.

The Early Rupelian (Early Oligocene) flooding corresponds toa maximum flooding surface that has been identified at severalsites in Colombia and Ecuador including the lower OrteguazaFormation in the Putumayo Basin (Christophoul et al., 2002;Jaramillo et al., 2011; Osorio et al., 2002). This flooding has beenidentified in the southern part of the Upper Magdalena Valley(Neiva Subbasin), the Putumayo Basin (Osorio et al., 2002) to thenorth (Fig. 1), and the Marañon Basin (Christophoul et al., 2002).

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6. Overburden

Vitrinite reflectance (Ro) data in strata from the Santa TeresaFormation in the Guaduas Syncline show Ro values of 0.54e0.60%(Gómez, 2001; Gómez et al., 2003), which represent maximumtemperatures of w95e105 �C for heating rates of 2e10 �C,according to the kinetic model of Burnham and Sweeney (1989).In the absence of evidence of other heating mechanisms, wecalculate that 2.5e4.5 km of overburden, with a thermal gradient of20e30 �C/km and a surface temperature of 25 �C -similar topresent-day values- would account for the observed Ro values.There are no robust constraints on the time associated with theaccumulation of such eroded overburden. However, Gómez (2001)calculated a concordant apatite-fission track (AFT) age of12.1 � 2.3 Ma (1s error) from sandstones of the Oligocene San Juande Río Seco Formation [Ro ¼ 0.64%; Temp¼ 115 �C], in the GuaduasSyncline, by using 20 apatites with average chlorine content of0.34%. An in-depth analysis of these data shows that a kineticpopulation of 19 apatites with chlorine content of 0.1% has an AFTage of 8.1�2.3Ma.We thus interpret this cooling age of 6e10Ma insamples that attained temperatures for full thermal resetting offluorapatites as a reasonable approximation for the age of end ofburial and accumulation.

In the Usme Syncline, a Ro value of 0.27% in the Usme Formation(Mora et al., 2008b) documents burial temperatures lower than50 �C. Using similar surface temperature and geothermal parame-ters as for the Guaduas Syncline, these paleotemperatures corre-spond to up to w1 km of overburden. Apatite (UeTh)/Hethermochronology (closure temperature w70 �C) in two sand-stone samples from the lower part of the Bogotá Formation alongits western limb shows highly reproducible ages (samples C540 andD937, palynologically dated as Middle/Late Paleocene and EarlyEocene, respectively; see Bayona et al., 2010), based on 4 aliquotsper sample, of 30.7� 1.8 Ma and 26.4�1.6 Ma (Bayona et al., 2010).These data reveal ongoing exhumation in the western limb of thissyncline by Late Eocene-Oligocene times. We believe that ca30e26 Ma is also a maximum age for the switch from sedimentaccumulation and burial to non-deposition in the core of thesyncline, where the Usme strata are preserved.

Paleotemperature estimates based on Ro and AFT data for theCenozoic units in the Floresta area are highly variable (Mora et al.,2010a), indicating a greater magnitude of burial the farther to thenorth in the direction of the El Cocuy area (see Fig. 1). In the north,at w6�200, the Concentración Formation has a Ro value of 0.80%,corresponding to a temperature of 140e150 �C, whereas 30 km tothe southwest Ro is 0.71% (temperature w115e130 �C). Based onthe considerations cited above, these estimates represent burialexceeding 4e6 km in the north and 1 km less in the southern areasampled. Thermal histories derived from Ro and AFT data in bothareas are consistent with an onset of exhumation occurring ca23e20 Ma (Mora et al., 2010a).

7. Stepwise cessation in sediment preservation along theEastern Cordillera

The transition from burial to exhumation occurred first in thesouthern central axial zone of the Eastern Cordillera (UsmeFormation) during the Rupelian-Early Chattian (ca 30eca 26 Ma).Subsequently, sediment accumulation stopped along the north-eastern axial zone of the Eastern Cordillera (ConcentraciónFormation) not before the Late Chattian (ca 23 Ma); and finally, itwas not until the Late Miocene (ca 10e6 Ma) that exhumation wasinitiated along the western flank of the Eastern Cordillera (SantaTeresa Formation). The observed age differences between the Ro/thermochronology estimates and the reported palynological dating

(Section 5.1) exposes the difference between the preserved sedi-ments and those that should have been accumulated but were lostby erosion, thus providing further evidence that the youngestpreserved sediments may not represent the last depositedsediments.

The Ro/thermochronology ages reported herein agree withprevious thermochronological, structural, and sedimentologicaldata (e.g. detrital zircon UePb ages, apatite-fission tracks, andpaleocurrents data), which indicate that initial exhumation of theEastern Cordillera took place during the Late Eocene-Early Oligo-cene (see Fig. 10 in Horton et al., 2010b) (Bande et al., 2012; Bayonaet al., 2008; Horton et al., 2010b; Mora et al., 2010a; Moreno et al.,2011; Nie et al., 2010; Parra et al., 2009b; Saylor et al., 2011; Toroet al., 2004). Evidence from the Usme Syncline (i.e. UeTh/He inapatite and lithological features) indicates onset of exhumation bythe end of the Eocene (Bayona et al., 2010). All these sets of datacombined suggest that sedimentation indeed ceased in thesouthern axial zone of the Eastern Cordillera by the Early Oligo-cene. Our data also support the hypothesis of a heterogeneousNeogene uplifting process across the EC (Bande et al., 2012; Bayonaet al., 2008; Horton et al., 2010a; Mora et al., 2008a, 2010a, 2006,2010b; Moreno et al., 2011; Parra et al., 2009b), being older inthe axial zone and having younger phases at the eastern andwestern flanks, and being older in the south than the north of theaxial EC.

8. Regional implications

Three different tectonic scenarios have been proposed to explainthe Cenozoic tectonic development of the axial zone of the EC andadjacent Magdalena and Llanos basins to the west and east,respectively. According to the first model, the EC corresponds toa large foreland basin system, including what are now the Llanosand the Magdalena Valley basins (Cooper et al., 1995; Villamil,1999). Initial breakup of the foreland basin occurred during theLate Oligocene, with a complete segmentation by the MiddleMiocene. The second model considers a fragmentation of a contin-uous Paleocene foreland basin during the Middle-Late Eocene, withcomplete isolation of the Llanos from the Magdalena Basin occur-ring by the Early-Middle Oligocene (Gómez et al., 2005; Hortonet al., 2010a, 2010b; Moreno et al., 2011; Nie et al., 2010; Parraet al., 2009a; Saylor et al., 2011). A third model proposes thata syn-orogenic basin to the east of the Central Cordillera wasinterrupted by several localized uplifts throughout the EC (Bayonaet al., 2008; Fabre, 1987; Sarmiento-Rojas, 2001; Shagam et al.,1984). These intrabasinal uplifts, which would give rise tomultiple intermontane basins, are the result of latest Cretaceous-Middle Eocene events of tectonic deformation.

The biostratigraphic data presented here indicate that the lastpreserved record of sedimentation along the present EC are notcoeval. Sediments were accumulated and preserved until the latestBartonian-earliest Rupelian? (Late Eocene-earliest Oligocene?) inthe southern central region (Usme Formation) and at least until theEarly Rupelian (Early Oligocene) in the northeastern central region(Concentración Formation), long before the major latest Miocene-Pliocene uplift of the EC (Van der Hammen et al., 1973). Incontrast, thewestern foothills (Santa Teresa Formation) and easternfoothills (Carbonera Formation) (Parra et al., 2009a) continuedaccumulating sediments during the Miocene. These marked timedifferences of the youngest preserved units across the EC suggestthat a single foreland that covered theMagdalena Valley, EC and theLlanos Basin was disrupted in the earliest Oligocene prior to theonset of major Late Neogene exhumation pulses, in contrast to thesimpler model that was proposed during the 1990s (Cooper et al.,1995; Villamil, 1999).

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Our palynological results indicate that during the Late Eocenethe Usme and Concentración formations were part of the CentralLlanos Foothills and Llanos Basin, as evidenced by the similarity infloras and the flooding event observed across this basin (Fig. 3),suggesting that depositional systems of the Llanos-EC basin werestill connected. Growth strata in the western flank of the EC andMagdalena Basin that record west-verging deformation of thewestern flank of the EC (Cortés et al., 2006; Gómez et al., 2003)mark the westernmost boundary of depositional systems withinthe Llanos-EC basin. The connection of this large depositionalsystem between the EC and the Llanos probably was broken duringthe earliest Oligocene, as has been suggested by the models ofGómez et al. (2005), Parra et al. (2009a), Horton et al. (2010b) andSaylor et al. (2011). This is further supported by the similaritybetween depositional environments of the EC, Llanos Foothills, andMagdalena Valley basins until the Late Eocene (Parra et al., 2009a;Saylor et al., 2011).

9. Conclusions

Biostratigraphic data from the youngest sediments preservedin all three synclines indicate different ages associated with theuppermost formations in each stratigraphic sequence. We esti-mated the age of the sediments from the Usme Formation (UsmeSyncline) as Bartonian-earliest Rupelian? (38e33 Ma), from theConcentración Formation (Floresta Syncline) as Late Lutetian-Early Rupelian (39e31.5 Ma), and uppermost Santa Teresa rocks(Guaduas Syncline) as Burdigalian (19e16 Ma). In addition, thecombination of biostratigraphic, thermochronometric, and pale-othermometric data suggests that cessation of sediment accu-mulation in the EC was diachronous. In the southern axial zone ofthe Eastern Cordillera (Usme Syncline), the shift from sedimentaccumulation and burial to non-deposition occurred during theLate Rupelian-Early Chattian (ca 30e26 Ma), whereas in thenortheastern axial zone of the Eastern Cordillera (FlorestaSyncline) it was estimated as latest Chattian-Aquitanian (ca23e20 Ma); and in the western flank (Guaduas Syncline) asTortonian-Messinian (10e6 Ma). These estimates agree with datesof published ages of exhumation of the EC, suggesting that theprocess of uplifting of the EC is very complex and happened inseveral steps. Finally, the palynoflora indicates the exclusivepresence of lowland plant communities in all three areas,including the Burdigalian (Early Miocene) Santa Teresa Forma-tion, suggesting that the EC still was less than 1000 m in elevationby the Early Miocene. Lowland conditions in the area of thepresent EC gradually ended between the Oligocene and the LateMiocene.

Acknowledgments

We thank the Colombian Petroleum Institute, the SmithsonianTropical Research Institute, the Corporación Geológica Ares, andColciencias for their financial, logistic, and technical support.Thanks to Andrés Pardo (Universidad de Caldas) for the palyno-logical analysis of most of the samples of the ConcentraciónFormation. We specially thank J. Saylor, B. Horton, J. Kellogg and ananonymous reviewer for their helpful comments. Natasha Atkinsimproved readability of the manuscript.

Appendix A. Supplementary material

Supplementary material associated with this article can befound, in the online version, at doi:10.1016/j.jsames.2012.04.010.

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