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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/256821901 Late Quaternary megafans, fans and fluvio-aeolian interactions in the Bolivian Chaco,Tropical South America Article in Palaeogeography Palaeoclimatology Palaeoecology · October 2012 DOI: 10.1016/j.palaeo.2012.04.003 CITATIONS 31 READS 161 8 authors , including: Some of the authors of this publication are also working on these related projects: THE PAYUNIA YARDANG FIELD IN ARGENTINA View projectÉdipo Henrique CremonInstituto Federal de Educação, Ciência e Tec… 28 PUBLICATIONS 95 CITATIONS SEE PROFILE Jan-Hendrik MayUniversity of Freiburg 64 PUBLICATIONS 470 CITATIONS SEE PROFILE Sonia TatumiUniversidade Federal de São Paulo 87 PUBLICATIONS 747 CITATIONS SEE PROFILE Jaime Argollo 69 PUBLICATIONS 853 CITATIONS SEE PROFILE All content following this page was uploaded by Sonia Tatumi on 22 February 2014. The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the srcinal documentand are linked to publications on ResearchGate, letting you access and read them immediately. Late Quaternary megafans, fans and uvio-aeolian interactions in the Bolivian Chaco,Tropical South America Edgardo M. Latrubesse a, ⁎ , Jose C. Stevaux b , Edipo H. Cremon c , Jan-Hendrik May d , Sonia H. Tatumi e ,Martín A. Hurtado f , Maximiliano Bezada g , Jaime B. Argollo h a Department of Geography and the Environment, the University of Texas at Austin, Austin, TX, 78712, USA b GEMA- Department of Geography, Universidade Estadual de Maringa, Maringa, PR 87020-900, Brazil c National Institute for Space Research (INPE) - Remote Sensing Division (DSR), São José dos Campos-SP, CEP 12227-010, Brazil d School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2500, Australia e Laboratório de Vidros e Datacões, FATEC, Faculdade de Tecnologia, Universidade Estadual de São Paulo, São Paulo, SP, 01124-060, Brazil f Institute of Geomorphology and Soils, Universidad Nacional de La Plata, La Plata, 1900, Argentina g Department of Geosciences, Universidad Pedagógica El Libertador, Caracas, Venezuela h Department of Geology, Universidad Mayor de San Andres, La Paz, Bolivia a b s t r a c ta r t i c l e i n f o Article history: Received 13 June 2011Received in revised form 3 April 2012Accepted 6 April 2012Available online 15 April 2012 Keywords: ChacoMegafansQuaternaryFluvio-aeolianPaleogeographyTropical South America The Chaco is a huge plain and a main biogeographic biome of South America dominated by subtropical semi-deciduousvegetationthatspreadsontheAndesfootslopeonmorethan800,000 km 2 throughBolivia,ArgentinaandParaguay.Theclimateistropicalwet – dryandtheSouthAmericanSummerMonsoon(SASM)leadstointen-sive convective rainfall during the summer season. Some of the world's largest river – fans such as the Parapetiand Grande rivers megafans developed in the Bolivian Chaco. Our research was based on morpho-sedimentaryinformation and sustained by 25 OSL dating of uvial and aeolian sediments. We demonstrate that thesemegafans are bigger than previouslypostulated by someauthors. Morphostratigraphic analysis, geochronologicaldata and regional correlations suggest that the Chaco megafans and large piedmont fans were generated andreached maximum development during the middle pleniglacial and early pleniglacial (ca. 60 to 28 ka) becauseofthepresenceofcolderandmoreseasonalconditions(dry – wetintensecontrastingseasons)thanthoseexistingtodayintheAmazonandtheBolivianplains.Wesuggestthatamainmechanismtriggeringthemegafandevelop-mentwasthepresenceofanintensemonsoonaleffectontheEastern ankoftheAndesthatenhancedrainfallbyorographicexcitationduringMIS3andtheearlypartofMIS2thatproducedanincreaseindischargeandsedimentsupply.Concomitantlyto uvialprocessesthede ationof uvialbeltsoccurredandbigsanddune eldsdevelopedby windsblowingout fromNorth toSouth following thesamepattern theSouth Americanlowerleveljetfollowspresently.MaximumariditywasreachedduringMIS2withthedepositionofloessdepositsonthepiedmontareasandmegafansurfaces,thecontinuousgenerationofaeoliandunesandaremarkabledecreaseinthe uvialactivity.Cold air mass related to the polar advection (friagens or surazos) probably affected the area with more intensityand frequency. The Lateglacial was also arid but probably less extreme than the LGM. During a good part of theHolocene the climatic conditions were still arid to semiarid but became more similar to the present sub-humidclimate since ~1.5 ka. During the Holocene, the megafans and aeolian systems didn't reach Late Pleistocene sizeand level of activity.© 2012 Elsevier B.V. All rights reserved. 1. Introduction Over the last decades, knowledge on the Quaternary record of thelarge tropical uvial systems of South America has increased substan-tially. A good part of this work has concentrated on the Amazon basinand the upper Parana basin, and today a general framework existswith regard to the response of the uvial system to climatic changein those areas, at least from the Last Glacial to present (see reviewsby Stevaux, 1994, 2000; Latrubesse, 2003; Latrubesse et al., 2005a). Eventhoughseveralauthorsnotedgeomorphicevidence foradynamicevolution of the uvial and aeolian landscapes of the Gran Chaco(Werding, 1977a, 1977b; Hanagarth, 1993; Iriondo, 1993), only a very limited number of studies are available on the more recent evolutionof the Andean foreland of the Chaco in northern Argentina, Paraguayand Bolivia. Virtually no chronological data has been published for thePleistocene record, and most research in the Chaco has concentratedonlonger-termlandscapeevolutionresultinginadvancesintheunder-standing of tectonic evolution, the geology of the sedimentary basins Palaeogeography, Palaeoclimatology, Palaeoecology 356 – 357 (2012) 75 – 88 ⁎ Corresponding author. E-mail address:
[email protected] (E.M. Latrubesse).0031-0182/$ – see front matter © 2012 Elsevier B.V. All rights reserved.doi:10.1016/j.palaeo.2012.04.003 Contents lists available at SciVerse ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo and sediment budgets since the Tertiary (Gubbels et al., 1993; Hortonand DeCelles, 1997, 2001; Barnes and Pelletier, 2006; Uba et al., 2006,2007; Barnes and Heins, 2009; Hulka and Heubeck, 2010). Most studies which have investigated the Quaternary sedimentary, geomor-phic and paleoenvironmental evolution of Chaco have either relied ex-clusively on remote sensing approaches (Werding, 1977a, 1977b; May,2006; Wilkinson et al., 2006, 2010; Hartley et al., 2010; Weissmann et al., 2010, 2011), or detailed but comparatively regional studies withfocus on the Holocene along the Andean piedmont in Bolivia (Servantet al., 1981; May, 2006; May et al., 2008a, 2008b; May and Veit, 2009) and the Paraguayan Chaco (Kruck, 1996; Barboza et al., 2000).The Gran Chaco, however, is a key area for Quaternary studies inSouth America for several reasons: the region contains one of the main uvial archives of the continent, storing sediments in the coupledsource-sinksystem of theAndes andlowlands. It is situated at the tran-sition between the lowlands of the Amazon basin to the north and thetemperate to semi-arid Pampean plain to the south. In addition, thelarge sand elds in the Chaco constitute a highly valuable proxy forthe reconstruction of wind patterns and atmospheric circulation intropicalSouthAmericaoverthecourseoftheQuaternary.Finally,there-gion has enormous biogeographic relevance, and has linked the largest uvial basins of South America through time: the Amazon and theParana. Therefore, this paper aims at (i) presenting a large-scale over-view of landforms and processes in the Bolivian Chaco, (ii) providingnew chronological data from key pro les in eastern Bolivia, and(iii) interpreting these results with regard to the paleoenvironmentalevolution of the Chaco, (iv) inserting the Chaco results into the SouthAmerican paleogeographic context. 2. Regional setting 2.1. The Chaco The Chaco is a huge plain and a main biogeographic biome of South America dominated by subtropical semi-deciduous vegetationthat extends more than 800,000 km 2 through Bolivia, Argentina andParaguay. It is borderedbytheAndean chainto the west,the Brazilianshield to the east, the Beni plain to the north and the Pampean plainto the south (Fig. 1). Geologically, the Chaco can be considered anAndean retroarc foreland basin that merges in continuity towardthe Chaco – Pampean platform. The landscape is characterized by anextremely at plain ranging in between ca. 600 and 40 m above sealevel (MASL) which is covered by an almost continuous layer of Quaternary sediments. The Chaco plain converges with the Pampaplain to the south and transitionally changes toward the Beni plainsof Bolivia (Moxos plains) to the north.Because of the Andean erosion, continental sediments, predomi-nantly uvial and secondarily lacustrine and aeolian, have beendeposited in the Bolivian Chaco at least since the Neogene (Gubbelset al., 1993; Horton and DeCelles, 1997; EjiUba et al., 2006; Latrubesse et al., 2010). The Subandean foothills with Tertiary and Pleistocenecontinental sediments are the easternmost and lower elevations of the Andean deformation (Hinsch et al., 2002).The Bolivian Chaco tropical conditions are dominated by the mon-soonal circulation system. During austral summer (January, February,March — JFM) the South American Summer Monsoon (SASM) (ZhouandLau,1998;Nogues-Paegleetal.,2002)leadstointensiveconvective Fig. 1. Overview of the setting and location of the Bolivian Chaco. Hypsometric map of the Bolivian Chaco plain. GB = Grande River basin, GF = Grande megafan, PB = ParapetiRiver Basin, PF = Parapeti megafan, OB = Otuquis – Tucavara basin, OF = Otuquis – Tucavara megafan.76 E.M. Latrubesse et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 356 – 357 (2012) 75 – 88 rainfall and causes a summer precipitation maximum. Another charac-teristic feature of the SASM is the presence of the South AtlanticConvergenceZone(SACZ).TheSACZisanorthwest – southeast-orientedband of enhanced precipitation that extends from the Amazon Basin tothe Atlantic Ocean. It is characterized by strong easterly winds thatcarry warm, moist air from the tropical Atlantic into the Amazon Basin.Upon reaching the Andes Mountains, this easterly air current turnssouthward, owing along the Andes Mountains (Gandu and Geisler,1991) forming a circulation feature known as the South American low-level jet (SALLJ).DuringtheSASM,aheavyrainfallzonealsoextendsovertheAltiplanoPlateauandthesouthernmostBrazilianhighland.Inbetweenbothareas,theCerradobiome(savannasofBrazil)spreadisdominatedbyaremark-able wet – dry climatic and hydrological regime. Santa Cruz de la Sierra(16°47 ′ S), for example, is located at the same latitude as the GoiasState, the core area of the Cerrado biome in Brazil. It has been suggestedthat the Cerrado biome is a main component of the SASM circulation(Xue et al., 2006). The Chaco tropical regime is semiarid to tropicalwet – dry. The Chaco presents a strong E – W rainfall gradient from1300 mm y − 1 to the East to near 400mm y − 1 at the Paraguay BoliviaBorder, increasing once again to more than 1200 mmy − 1 at the sub-Andean Mountains and hillslopes due to the Andean orographic effect.Heavy orographic, convective rainfall occurs when the moisture-ladennortherly low-level ow travels along the eastern slopes of the Andes(e.g., Vuille et al., 1998; Garreaud et al., 2003; Vizy and Cook, 2007). The dominant winds come from the northern quadrant and persist during agood part of the year blowing out with mean velocities above 4.5 ms − 1 producing signi cant de ation on the Chaco plain and generating dusttransport and aeolian dunes.During winter, (June, July, August — JJA) cold air incursions fromthe south (polar advections) can periodically cause severe tempera-ture drops in the Chaco plain and additional rainfall throughout theyear (Garreaud, 2000). The cold mass incursions receive the name of “ surazos ” inBoliviaor “ friagems ” inthesouthwesternBrazilianAmazon.The largest uvial systems debouching from the Andes on theSubandean piedmont and the Bolivian Chaco plain are the ParapetíRiver, the Grande and the Pilcomayo River. The Pilcomayo River,located to the south, is not analyzed in this study. The drainage of theParapeti in the mountain area, upstream from the Andean footslopes,was estimated to be ~8000 km 2 while the Grande River drainagebasinis59,800 km 2 (Guyotetal.,1994)(Fig.1).Thereliefindex(differ- encebetweenmaximumandminimumelevationofthedrainagebasin)was estimated to be 4546 m and 2672 m, respectively (Barnes andHeins, 2009). Additionally, amongst the major rivers, several smallerephemeral catchments drain the subandean zone and spread on thepiedmont.The strong seasonality also controls the hydro-sedimentologicalregime of the Chaco rivers (Latrubesse et al., 2005a). For example, 75%to90%ofthewashloadtransportintheRioGrandeconcentratesduringthe rainy season (JFM). At the apex of the Grande fan (Abapo gaugestation), the mean annual sediment concentration is 8410 mgl − 1 andthe yield was estimated to be 2280 t km 2 y − 1 (Guyot et al., 1994). While the mean annual discharge is 334 m 3 s − 1 , 63% of the annualdischarge is delivered from January to March and very low dischargesoccur from April to October. The Parapeti River suffers more extremeconditions and becomes dry during a good part of the year when ow-ing through the Chaco plain and the mean annual discharge at theAndean footslope is 79 m 3 s − 1 and the sediment yield is 2590 km 2 y − 1 (Guyot et al., 1994). 2.2. The Chaco megafans Large depositional megafans are characteristic landforms of manytropical uvial systems related to both orogenic active belts and fore-land settings, and internal basins and plateaus. Some of the largestmegafans spreading over thousands of kilometers have developed inthe Gangetic plain of India, including the Kosi and Gandak megafans(Wells and Dorr, 1987; Sinha and Friend, 1994), at the Pantanal of Mato Grosso (Tricart, 1982: Assine and Soares, 2004; Assine, 2005; Assineetal.,2005)andinOkavango(McCarthyetal.,1991).However, the largest development of uvial megafans concentrates in theChaco-plain. The Chaco rivers show, as a common geomorphologicfeature, alluvial fans ranging from typical piedmont alluvial fans togiant uvial fans or megafans (Iriondo, 1993; Horton and DeCelles,2001; Cafaro et al., 2010) that include the largest fans of the world.Thelargestfans generatedby ve majorrivers from northto southare: Grande, Parapetí, Pilcomayo, Bermejo and Juramento megafans(Iriondo, 1993; Cafaro et al., 2010). In between the megafans, a num- ber of minor rivers exist that occupy and rework alluvial sediments of olderalluvialbeltsfromthemajorfans.Someofthesesmallersystemshave even created their own fans of considerable dimensions.The evolution of the Chaco megafans seems to have started in theTertiary (Horton and Decelles, 2001) but megafans are still activetoday. Interaction between uvial and aeolian processes is remark-able in the Bolivian Chaco where large sand dune elds have beenepisodically active since the Late Pleistocene because of the de ationof alluvial sediments. The Grande and Parapeti megafans have beenformed by several episodes of sedimentation during the Late Quater-nary spreading on the at surface as an aggradational alluvio-aeolianplain extending from the Sub-Andean piedmont toward the East andSouth (Fig. 1). The fans suffered, however, from constraints on theirdevelopmentbecauseoftheexistenceofrockhillsformedbyMesozoic,Paleozoic and Proterozoic rocks and ranges suchas the Chiquitosrangethat extend in a E – W direction rising on the Chaco plain (Fig. 1). 3. Methods Research methods combined geomorphologic mapping, eld sur-veys and geochronology of the deposits. Several eld work expeditionswere made between 2006 and 2008 and landform analyses and strati-graphic surveys were performed. We performed the geomorphologicmapping using DEM-SRTM and Landsat Geocover and CBERS images.Elevationdatawasprocessedtoobtaingeo-morphometricdata.Thepa-rameter amplitude of relief, with application on local 5×5 pixel win-dows was estimated (e.g. Liu, 2008). Because of the low local relief of theChacoplainwecustomizedshadeschemesandpalettestohighlightthe depositional landforms. Multispectral images were processed bycomposite bands and enhancement. The landforms were identi edthrough visual interpretation and digital mapping. The drainage basinswere calculated based on SRTM processing using the software ArcGIS(ESRI, 2004).OSLdatingwasprocessedattheLaboratoryofGlassoftheUniversityof Sao Paulo. A total of 25 dates of uvial and aeolian deposits wereobtained (Tables 1, 2 and 3). Quartz grains with 88 – 180 μ m size wereobtained after chemical treatments with: HF 20% for 45 min, 20% HClfor 2 h and heavy liquid (SPT). OSL shine down curves were measuredwith a Daybreak Nuclear and Medical Systems Inc., model 1100-SeriesAutomated TL/OSL system, the quartz crystals were stimulated withlight-emitting diodes (LEDs 470 nm) and an optical lter Hoya U-340was used for detection. All the γ -irradiations were performed 60 Cowith a dose rate of 28.7 Gy/h and for the bleaching experiments thesamples were submitted directly to sunlight for 16 h. Natural radioac-tive isotopes contents were determined with gamma spectroscopy,using Inspector portable spectroscopy workstation, lead shield model727 and Na I(Tl) detector model 802 (Canberra Inc.) and standardssoil JG-3,JR-1,JG-1a,JB-3. The contribution of annual cosmic ray was as-sumed as 250 μ Gy/year and no correction of water concentration wasmade.Paleodoses values were evaluated by regeneration method withmultiple aliquots with preheating temperature at 260 °C for 5 min,throughthemeanvaluemodelusing15aliquots.Fig.2showsatypicalOSL growth obtained with these samples. 77 E.M. Latrubesse et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 356 – 357 (2012) 75 – 88 4. Results 4.1. Geomorphology of the Bolivian Chaco Based on topography analysis of the Andean foreland, mainlythree different but interrelated geomorphic landscape elementswere distinguished: the bajada along the Subandean Ranges, the largermegafans occupying most of the foreland, mostly inactive dune eldssuperimposed on them, and loess deposits (Fig. 3). 4.1.1. Bajada Smaller fans form a continuous bajada and large proximal fans arelocated along the piedmont. The largest one is formed by the PiraiRiver and minor fans coalesce with the west border of the Grandemegafan such as that of the Seco River (Fig. 1). The shorter piedmontfans have steeper longitudinal pro les and likely coarser sedimentsthan the Grande. Their existence constrained the lateral shifting of theGrande River fan on most proximal areas of the piedmont. The pied-mont bajada has continuity to the south, covering the inter-megafanproximal area between the Grande and Parapetí, where minor fansweregeneratedbysmallbasinssuchasElEspino,Saipurú,Haipapucuti,Chorritos/Pirití, Caragua and Ancasoro (Fig. 1). 4.1.2. Megafans TheRioGrandemegafanspreadstothenorthreachingasfarastheMamoré basin. The fan apex was located at the Andean footslope in asimilar position than today and a second nodal point, with a new dis-tributary pattern, used to be active near El Carmen (62°59 ′ 37 ″ W and17°04 ′ S) where the river ows toward the Amazon basin (Fig. 3).The Grande megafan spreads on an area of ~58,140 km 2 (Table 4).Today the system drains toward the Amazon basin but paleochannelsindicate that in the past the system may have distributed channels tothe south as well, coalescing with the Parapeti megafan (Fig. 3). Thealluvial belts of the Seco River are coalescing with the sediments of the Grande's apex-proximal megafan zone.The Parapeti megafan is located to the south of the Grande Rivermegafan. Presently, the Parapeti River lacks the discharge to reachthe collector systems and ends in the Izozog swamps, a remarkablewetland system of the Bolivian Chaco located ~130 km from theAndean footslopes. As indicated by paleochannels and topography,the Parapeti River shifted along a broad area discharging into theParaguay River, in the Pantanal basin, crossing the Paraguay territoryand coalescing with the Pilcomayo megafan or owing to the northtoward the Amazon watershed (Fig. 3).The old alluvial belts and paleochannels of the Parapeti River ex-tend further than the present ones. The area of the late PleistoceneParapeti megafan was near 60,000 km 2 (Fig. 3, Table 4). The apex of the Pleistocene fan was located at the same position as today andseveral of the uvial belts spread toward the southeast – south. A set of younger paleochannels are clearly visible at the apex area where thesurface of the old fan is partially dissected. The body of the megafan iscomplex because some main alluvial belts acted as a nodal point fromwhere new distributary systems evolved. The most conspicuous nodalpoint of ancient uvial belts is that recorded close to the border be-tweenBoliviaandParaguay.AtthispointtheParapetigeneratedseveralnew branches that were coalescing with the paleochannels of thePilcomayo River megafan (Figs. 3, 4). At that time the Parapeti was atributary of the Pilcomayo discharging water and sediments into theParaguay River which is a main tributary of the Parana uvial basin(Fig. 3).AlargefanwasalsogeneratedtotheeastbytheOtuquis – Tucavarabasin where the Otuquis or San Silvestre swamp is currently located(Fig. 3). The headwaters drain the hills and ranges formed duringthe Paleozoic and Mesozoic such as the Santiago Range and olderlow elevation Quaternary units. A complex network of paleochannelsformed a fan that spread over 5695 km 2 (Table 4). The fan is 125 kmin length and reaches up to 74 km width at the distal part when itreaches the Pantanal basin at the Paraguay River collector system(Parana River basin).The Parapeti and Grande megafans as well as the piedmont bajadafans are multi-cyclic landforms that include alluvial belts of differentage and generations. In this context, the more proximal lobes reworkolder alluvial belts and dissipate aeolian deposits in the proximalarea. The proximal younger lobes are identi ed in remote sensingproducts by a more diverse mosaic of vegetation than the older andmore stable fan units. In this younger lobes, a complex lower terrace, Table 1 Natural radioactive contents in sediments.Sample name Th(ppm)U(ppm)K(%)BOL TL 1 3.32±0.12 0.79±0.45 0.61±0.09BOL TL 2 4.39±0.16 1.17±0.23 1.0±0.14BOL TL 3 5.86±0.21 1.74±0.39 0.88±0.13BOL TL 4 4.18±0.15 1.19±0.49 0.91±0.13BOL TL 5 10.43±0.38 2.98±0.07 1.37±0.20BOL TL 6 6.78±0.24 1.93±0.44 0.65±0.09BOL TL 7 11.14±0.40 2.66±0.94 1.18±0.17BOL TL 8 2.41±0.09 0.72±0.42 0.56±0.08BOL TL 9 5.21±0.19 1.34±0.26 0.16±0.02BOL TL 11 11.77±0.42 2.93±0.88 1.12±0.16BOL TL 12 3.53±0.13 1.31±0.24 0.71±0.10RG - 8 10.29±0.37 3.01±0.60 1.59±0.23RG - 5 3.27±0.12 1.32±0.38 0.77±0.11D1 - 6 6.70±0.24 1.96±0.71 0.67±0.10RS - 10 5.98±0.22 2.05±0.44 1.38±0.20D3 - 1 2.42±0.09 0.69±0.15 0.68±0.10D3 - 9 3.52±0.13 0.79±0.09 0.50±0.07RG - 6 7.94±0.29 2.61±0.19 1.74±0.25D3 - 2 1.65±0.06 0.703±0.711 0.835±0.121D 1 5 3.4±0.34 0.84±0.08 Lower than detection limitD 1 1 3.2±0.3 1.2±0.1 Lower than detection limitD 4 1 3.6±0.4 0.86±0.09 Lower than detection limitD 2 1 1.7±0.2 0.76±0.08 Lower than detection limitRG-10 5.5±0.6 2.3±0.2 Lower than detection limitD 3 3 2.2±0.2 0.41±0.04 0.030±0.003 Table 2 Annual dose rate, paleodoses and ages obtained for sediments.Sample name Annual dose rate( μ Gy/y)Paleodose(Gy)OSL age(kyr)BOL TL 1 1332±215 8.84±0.45 6.6±1.4BOL TL 2 1901±218 2.5±0.1 1.3±0.2BOL TL 3 2042±248 13.21±0.63 6.5±1.1BOL TL 4 1804±273 10.71±0.56 5.9±1.2BOL TL 5 3203±250 30.2±1.5 9.4±1.2BOL TL 6 1917±228 8.55±0.50 4.5±0.8BOL TL 7 2984±447 62.7±3.1 21.0±4.2BOL TL 8 1188±199 2.6±0.1 2.2±0.5BOL TL 9 1156±107 2.72±0.09 2.4±0.3BOL TL 11 3039±425 17.05±0.97 5.6±1.1BOL TL 12 1583±176 2.12±0.09 1.3±0.200RG - 8 3431±420 68.6±3.6 20.0±3.5RG - 5 1621±221 17.4±0.9 10.7±2.0D1 - 6 1944±299 35.4±1.8 18.2±3.7RS - 10 2641±334 2.4±0.2 0.9±0.2D3 - 1 1303±147 1.37±0.09 1.1±0.2D3 - 9 1229±108 12.8±0.6 10.4±1.4RG - 6 3303±329 35.7±1.7 10.8±1.6D3 - 2 1411±312 0.91±0.06 0.7±0.2D 1 5 720±50 6.4±0.3 8.9±1.0D 1 1 820±55 10.0±0.5 8.8±1.0D 4 1 740±50 24.2±1.2 32.8±3.8D 2 1 570±35 2.2±0.1 3.9±0.4RG-10 1260±100 67.6±3.4 53.7±6.9D33 560±30 0.41±0.02 0.030±0.00378 E.M. Latrubesse et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 356 – 357 (2012) 75 – 88
