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Terra preta soils and their archaeological context in the caqueta basin of southeast colombia


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  • 1. Society for American ArchaeologyTerra Preta Soils and Their Archaeological Context in the Caqueta Basin of Southeast ColombiaAuthor(s): Michael J. Eden, Warwick Bray, Leonor Herrera, Colin McEwanSource: American Antiquity, Vol. 49, No. 1 (Jan., 1984), pp. 125-140Published by: Society for American ArchaeologyStable URL: .Accessed: 06/06/2011 22:13Your use of the JSTOR archive indicates your acceptance of JSTORs Terms and Conditions of Use, available at . JSTORs Terms and Conditions of Use provides, in part, that unlessyou have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and youmay use content in the JSTOR archive only for your personal, non-commercial use.Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at . .Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printedpage of such transmission.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact for American Archaeology is collaborating with JSTOR to digitize, preserve and extend access toAmerican Antiquity.
  • 2. TERRA4PRETA SOILS AND THEIR ARCHAEOLOGICAL CONTEXT INTHE CAQUETA BASIN OF SOUTHEAST COLOMBIAMichael J. Eden, Warwick Bray, Leonor Herrera, and Colin McEwanInvestigation of dark earthsfrom two archaeological sites near Araracuara, on the Rfo Caqueta in ColombianAmazonas, indicates that these soils are anthropic, with characteristics similar to those of the terra preta soils ofthe Brazilian Amazon. The Araracuara sites belong to the Camani (plainware) phase of the second to ninthcenturies A.D. and to the Nofurei phase (ninth to seventeenth centuries) withpottery of the Polychrome Tradition.The Araracuara examples are the first archaeological terra preta soils analyzed from west of Brazil, althoughsimilar materials are reportedfrom Ecuador and Peru. The problems of recognizing and dating thefirst appear-ance of terra preta soils are discussed, and a plea is made for closer collaboration between archaeologists andsoil scientists.Terra preta soils have been reported from many places along the mainstream of the Amazon andits tributaries (Hilbert 1968; Sombroek 1966). The soils are generally free-draining, dark-coloredand relatively fertile in character. They normally contain indigenous artifacts and appear to becoincident with areas of relatively dense Precolumbian settlement. In the past, the origin of thesesoils has been unclear. The possibility of a natural origin has been considered and the assumptionmade that their favorable fertility served to attract indigenous settlement (Soares 1963); alternatively,the terra preta has been viewed as an "archaeological soil" and its characteristics assumed to derivefrom the accumulation of domestic organic waste around Precolumbian settlements (Gourou 1949).Detailed analyses of terra preta sites and materials have recently tended to confirm an anthropicorigin; on this basis, Sombroek (1966:158) describes a terra preta from the Santar6m region as "akind of kitchen-midden, developed at the dwelling sites of Pre-Columbian Indians." Similarly, soilinvestigations by Ranzani et al. (1970), Vieira et al. (1971) and Smith (1980) lead them to acceptan anthropic origin for the terra preta.The distribution of terra preta sites extends widely across the Brazilian Amazon (Brochado andLathrap 1982; Falesi 1972; Hilbert 1955, 1968; Palmatary 1960; Sim6es 1967, 1974; Smith 1980;Sternberg 1960). They are recorded from Maraj6 island at the mouth of the Amazon, along down-stream tributaries like the Xinguiand Tocantins, in the middle Amazon near Santarem and Manaus,and westwards almost to the Colombian frontier at Tapurucuara on the Rio Negro and at Mangueirason the Rio Japura. Terra preta soils are also reported from Aripuana in northern Mato Grosso, andalong the Transamazon highway in the state of Para.In the past, terra preta soils have been commonly reported along major rivers, but it is nowapparent that they also occur on interfluvial sites. The soils have been observed by one of us (Eden)along the northern sector of the Santar6m-Cuiaba highway, while Smith (1980) reports other in-terfluvial occurrences in eastern Amazonia. According to Smith, riverine terra preta soils are deeperand more extensive than those on interfluves. He recognizes a sharply bimodal distribution in sitesize. The average area of his riverine sites is 21.2 ha, with the largest extending up to 4 km alongthe riverbank and covering as much as 90 ha. In contrast, the terra preta sites of interfluvial areasconsist of circular or lenticular deposits with an average extent of only 1.4 ha, with no site largerthan 6 ha. Smith (1980) considers riverine sites to have developed in association with relativelyMichael J. Eden, Department of Geography, Bedford College, London University, London NW] 4NS, EnglandWarwick Bray, Institute of Archaeology, London University, London WCIH OPY,EnglandLeonor Herrera, Instituto Colombiano de Antropologfa, Apartado Nacional 407, Bogotd, ColombiaColin McEwan, Department of Anthropology, University of Illinois, Urbana IL 61801, U.S.A.American Antiquity, 49(1), 1984, pp. 125-140.Copyright Oc 1984 by the Society for American Archaeology125
  • 3. 126 AMERICANANTIQUITY [Vol. 49, No. 1, 1984]extensive indigenous settlements, while the smaller interfluvial sites are probably the remains ofindividual malocas (large multifamily dwellings).During 1977, scientists of the Colombian Amazonas Expedition undertook fieldwork in the centralCaqueta basin of eastern Colombia. Archaeological investigations resulted in the identification ofnumerous sites of Precolumbian settlement (Bray et al. 1977; Herrera 1981; Herrera et al. 1982).In several places, where detailed excavations were undertaken, terra preta soils were encounteredwhich displayed similarity to those described from the Brazilian Amazon. Such soils, which do notappear to have been previously analyzed from the Colombian Amazon, are also considered to owetheir distinctive features to anthropic influences. In the present paper, earlier Brazilian data on terrapreta soils and their archaeological context are briefly reviewed. Information from the Colombiansites is then presented and compared, and its broader implications are discussed.TERRA PRETA SOILS IN THE BRAZILIAN AMAZONDetailed information on terrapreta soils in the Brazilian Amazon is given by Sombroek (1966),Ranzani et al. (1970), Vieira et al. (1971), Falesi (1972) and Smith (1980). Sites are reported to befree-draining in character and often located where higher land comes close to, and has good visibilityof, navigable waterways. Smaller sites have also been encountered on interfluvial areas. Terrapretasoils are most commonly present on Pleistocene terrace levels, but also occur on the older planaltosurface of Plio-Pleistocene age. On the latter surface, at Santar6m, fine-textured terrapreta soils arejuxtaposed with kaolinitic yellow latosols over a parent material of common age and composition(Sombroek 1966).Terrapreta soils in eastern Amazonia are principally distinctive with respect to their color, whichremains relatively dark into lower horizons. Colors range from black in the topsoil to dark brownor strong brown at 70-100 cm in depth. This contrasts with the color of adjacent kaolinitic yellowlatosols which are paler at depth (Ranzani et al. 1970; Sombroek 1966). According to Sombroek(1966), the dark coloration of terra preta horizons appears to be associated with only moderatelyhigh levels of organic carbon; he suggests that soil darkening may result from a complex formationof organic matter and calcium, forming a coating on the soil particles.In addition, terra preta soils are commonly less acid than adjacent free-draining soils. A widerange of pH values is encountered, but according to Smith (1980:562), "the pH of sampled blackearth sites averaged 5.4 . . ., whereas the pH of oxisols and ultisols in Amazonia is usually under5." The reduced acidity reflects a relatively high concentration of exchangeable calcium, whileexchangeable magnesium may also be slightly increased. In addition, available phosphorus is usuallyrelatively high (Sombroek 1966; Vieira et al. 1971).Archaeologically, the terra preta phenomenon is a generalized trait, and is not exclusive to anysingle cultural group or ceramic tradition. Smith (1980) raises the possibility that the deepest levelsof some terra preta soils may go back to the preceramic period, though this is frankly speculative.In excavated terrapreta sites, the quantity of archaeological material tends to diminish with depth,and the lack of pottery at the base of a few terra preta soils need not therefore indicate great age.Present evidence does not allow us to state unequivocally whether or not the earliest sites of theceramic period in Amazonia are of terra preta type. The oldest radiocarbon date for a terrapreta is 2400 ? 75 years: 450 B.C. (GrN-4328) from Paredao near Manaus (Hilbert 1968), althoughon archaeological grounds this figureis generally regardedas too early. Much furtherwest, the Hupa-iya site on the Rio Ucayali in Peru is a terra preta (Lathrap, personal communication) and wasoccupied between ca. 200 B.C. and A.D. 100 (Lathrap 1970:117-120). By the start of the Christianera the picture becomes clearer, and dated sites are more numerous. The Bom Sucesso site, onCareiro Island, has a date of 2050 ? 120 years: 100 B.C. (L-198A) on caraipe temper from potsherdsfound in a terrapreta (Carneiro 1974; Sternberg 1960). At the Poc6 site, on a tributary of the RioNhamunda, the earliest component (the Poc6 phase) has dates of 2015 ? 95 years: 65 B.C. (SI-2774), 1840 ? 90 years: A.D. 110 (SI-2776) and 1745 ? 115 years: A.D. 205 (PN-8028) (Hilbertand Hilbert 1979). These figures correspond reasonably well with the ones from Itacoatiara of 1864
  • 4. REPORTS 12778oW 720 w-4PN1020N~~~~~~~~~~~~~~~~~~~2NIJLandover m A Z I L000 > < a Pedrera l~~~~~~~~~~~~~EC U A D O R./ t % 9<_ >{ , O~ 100 200 b-78?,W i 9, . 74eW 720W 4 7ceraFigure 1. Southeastern Colombia and adjacent areas.? 58 years: A.D. 86 (P-372) and from Manacapuru with 1525 ? 58 years: A.D. 425 (P-406) fromits upper levels (Hilbert 1968).At the other end of the chronological range, European trade beads have been found in some terrapreta soils of the middle Amazon, and sites with pottery of the Santar&mstyle can be linked withthe historical Tapaj6 Indians (Palmatary 1960).Taken at face value, this evidence suggests that the first unambiguous terrapreta sites (whateverthey may mean in terms of land use) do not make their appearance in Amazonia much before thestart of the Christian era. However, this may be a false impression, based on inadequate sampling.Few Amazonian sites are reliably dated; archaeologists rarely give competent descriptions of soilprofiles and, because of the lack of analytical data, there is as yet no agreement about what constitutesa "minimal" terra preta in terms of its blackness or of its physical and chemical properties.The sort of problem which arises is exemplified by the controversy over the age of the B6a Vistasite, one of the more plausible candidates for early terra preta status (Hilbert and Hilbert 1980).B6a Vista is a settlement of the Poc6 phase and has produced two early radiocarbon dates: 3280? 45 years: 1330 B.C. (PN-7542) and 2950 ? 130 years: 1000 B.C. (PN-7453), which are consistentwith each other but irreconcilable with the three dates from Poc6 itself. Brochado and Lathrap(1982:25), who see Saladoid affinities in the Poc6 style, are inclined to accept the earlier dates, whilethe excavators emphasize links with the Taquara and Barrancoid traditions and prefer the laterseries of dates (Hilbert and Hilbert 1979, 1980). Peter Paul Hilbert informs us (personal commu-nication) that the sherds from B6a Vista were badly eroded and difficult to classify, and that theradiocarbon samples came from the very bottom of the cuts "already out of the Terra Preta in theproper sense, but mixed up with yellowish Kaolinitic latosols."And there, for the moment, the matter must rest until more sites are excavated and more soil
  • 5. 128 AMERICAN9.. . . . , , .
  • 6. REP. . **.. **,.. - : P%*:e.?W. *.; *-. , V 4,itp v;r.,-Figure 3. Eastern margin of the sandstone massif at
  • 7. 130 AMERICANANTIQUITY [Vol. 49, No. 1, 1984]S S sOmt"0~~~~~LaSaSIte3/4aracuaraC AO. LIII~~~~FloodplainSandstone massif1KilometresFigure 4. Sites in the Araracuara region.Two sites are described, one located near Araracuara on a colluvial parent material derived fromthe sandstone massif and the other on a low terrace downstream near La Sardina (Figure 4). Thesite numbers are those of the original field report (Bray et al. 1977).Analysis of the soils was undertaken using standard procedures (Black et al. 1965). Particle sizewas obtained using the pipette method. Organic carbon was determined by the Walkley-Blackmethod. Exchangeable metallic cations were extracted with neutral ammonium acetate, and mea-sured by atomic absorption spectrophotometer or flame photometer. Exchangeable aluminum wasextracted with KCI and determined by titration with NaOH. Available phosphorus was determinedusing the Bray method. The pH was measured in a 1:2/2 suspension in H20.Site 3/4: AraracuaraAdjacent to Araracuarathe relatively flat summit area of the sandstone massif is covered by forestor shrub vegetation. Rock outcrops are common and are interspersed with areas of poorly drainedacid soils, consisting of bleached quartz sand overlain by a thick organic horizon. Drainage conditionsimprove on flanking slopes where sandy colluvial materials give rise to less acidic, brown sandysoils that normally carry rainforest. The colluvial soils have been classified as Inceptisols (J. Morelo,personal communication).Approximately 1 km northwest of Araracuara, overlooking the river and adjacent to the contem-porary portage route which crosses the sandstone massif, an area of terra preta was encountered(Figure 3). The soil, which is located on the upper flanking slope of the massif, is developed incolluvial materials similar to those of adjacent Inceptisols. The soil is underlain by weatheredsandstone at a depth of 100-150 cm.The investigated area of terra preta is partly covered by mature secondary forest and partly byan experimental manioc plantation. Some 40 small test pits and one larger trench, 2 x 1 m, wereexcavated down to sterile subsoil. These pits were scattered over more than 2 ha of dark soil, but
  • 8. REPORTS 131Table 1. Representative Soil Profile for Terra Preta at Araracuara (Site 3/4).Location: 1.5 km north-west of AraracuaraAltitude: 360 m (estimated)Relief: very gently inclined (10) upper hillslopeParent material: sandstone colluviumDrainage: free drainingVegetation: mature secondary forest0-7 cm Very dark greyish brown (IOYR3/2) fine sandy loam. Structureless. Friable. Finecharcoal fragments and few sherds. Abundant roots. pH 4.37-36 cm Dark reddish brown (5YR2/2) fine loamy sand. Weak fine granular structure. Friable.Common visible pores. Few fine charcoal fragments and sherds. Common roots.pH 4.536-49 cm Very dark brown (1OYR2/2) fine loamy sand. Moderate fine subangular blockystructure. Friable. Common visible pores. Few sherds. Common roots. pH 4.549-74 cm Dark brown (7.5YR4/4) sandy clay loam, with abundant strong brown (7.5YR5/8)mottling and incipient iron concretions. Moderate fine subangular blocky structure.Firm. Common visible pores. Few sherds. Common roots. pH 4.874-106 cm Strong brown (7.5YR5/6) sandy clay loam, with common to abundant, hardened darkred (1OR3/6) iron concretions. Strong fine subangular blocky structure. Firm.Common visible pores. Few roots. pH 4.8106 cm + Weathered sandstoneTable 2. Analytical Data for Terra Preta and Adjacent Inceptisols at Araracuara(Site 3/4).Physical CharacteristicsSand Silt Clay(0.05-2.00 mm) (0.002-0.05 mm) (<0.002 mm)Texture Class (%) (%) (%)Terrapretaa) 0-10 cm Loamy sand 85 8 775-80 cm Sandy clay loam 66 10 24Inceptisolsb) 0-10 cm Sandyloam 74 11 15c) 0-10 cm Sandyloam 78 7 15d) 0-10 cm Sandy clay loam 54 22 24e) 0-10 cm Sandy clay loam 46 22 32Chemical CharacteristicsExchangeable Cations Available Organic(me/l100Og) P CarbonCa Mg Na K Al (ppm) (%) pHTerrapretaa) 0-10 cm 0.07 0.04 0.04 0.08 0.71 71 3.8 4.375-80 cm 0.07 tr tr tr 1.42 17 1.6 4.8Inceptisolsb) 0-10 cm 0.07 0.04 0.04 0.08 0.93 12 2.0 4.4c) 0-10 cm 0.07 0.04 0.04 0.08 1.00 13 2.1 4.2d) 0-10 cm 0.05 0.04 0.17 0.10 1.35 25 4.2 4.5e) 0-10 cm 0.05 0.04 0.17 0.15 1.57 25 4.4 4.0
  • 9. 132 AMERICANANTIQUITY [Vol. 49, No. 1, 1984]Table3. RepresentativeSoil Profilefor TerraPretaat LaSardina(Site20).Location:400 m inland,rightbankof the CaquetariverAltitude:200 m (estimated)Relief: gently sloping (30) terrace marginParentmaterial:terracealluvium,with igneous/metamorphicrockdebrisDrainage:imperfectlydrainedVegetation:matureforest0-15 cm Verydarkgrey(10YR3/1) sandyloam. Weakfinegranularstructure.Veryfriable.Fewfinecharcoalfragmentsandsherds.Abundantroots.pH 4.715-90 cm Verydarkgreyishbrown(1OYR3/2)sandyloam. Weakfinesubangularblockystructure.Friable.Fewfinecharcoalfragmentsand fewsherds.Commonto fewroots.pH 4.590-120 cm Verydarkgreyishbrown(1OYR3/2)sandyclayloam, withcommonweatheredrockfragments.Weakfinesubangularblockystructure.Friable.Veryfinecharcoalfragmentsandfew sherds.Fewroots.pH 4.5120cm + Weatheredrocksubsequent investigations by Andrade and Botero (personal communication) have shown that thesite consists of approximately 6 ha of classic black terra preta and 20 ha of brown anthropic soil.Our test pits outside the area of dark soil produced no archaeological material, but within theblack terra preta sherds were present throughout the dark earth, though diminishing in numbersbetween 40-70 cm in depth. At this site, as in others investigated, the archaeological depositcontained charcoal, chips and spalls of chert, an unusual number of small gravelly pebbles, andmany broken fragments of quartz. The chert, and possibly also the quartz fragments, may well bethe residue of tool manufacture. Although the stone chips show no clear evidence of human work-manship, such items do not occur to a significant extent in comparable, non-archaeological sites inthe area.A representative soil profile from the site is given in Table 1. In Table 2, analytical data for theprofile are provided, together with topsoil analyses from adjacent forest sites where similar colluvialmaterials are present but terra preta characteristics are lacking.Site 20. La SardinaLa Sardina is located on the Caqueta river approximately 20 km downstream of Araracuara(Figure 4). In this area, land flanking the river consists mainly of contemporary floodplain or of lowdepositional terraces of Pleistocene age. Floodplain sediments are mainly silty clay loam to clay intexture, while terrace materials are sandy clay loam to sandy clay, often overlying gravel at depth(Eden et al. 1982). Floodplain and terrace soils in the area have been classified as Inceptisols (J.Morelo, personal communication). Within and adjacent to this stretch of river, there also occurlocal outcrops of igneous and metamorphic rocks, which are outliers of the Guiana Shield complex.At La Sardina the terrapreta lies in mature forest on the right bank of the Caqueta river. Adjacentto the river is a relatively narrow floodplain zone which gives way approximately 400 m inland toa low terrace level. Weathered igneous/metamorphic rocks outcrop nearby and appear to havecontributed to local parent materials. Terra preta soils are present across the floodplain-terraceboundary, and are associated with archaeological materials.The precise extent of the archaeological site is unknown, although it clearly covers several hectaresand is probably within the range of Smiths (1980:563) "riverine" class of sites. Cultural materialoccurs on the floodplain immediately adjacent to the river, and extends for 500 m inland onto thelow terrace. Within the area of the site, intensity of human activity was not necessarily homogeneous.In a pit (Test pit A) on the floodplain, the soil was black and contained sherds throughout, with amarked concentration at 30-50 cm, just above the base of the material. The water table was reachedat 55 cm. This zone may perhaps represent a midden or house garden. In Test pit B, on the terrace,
  • 10. REPORTS 133Table4. AnalyticalData for TerraPretaandAdjacentInceptisolsat LaSardina(Site20).PhysicalCharacteristicsSand Silt Clay(0.05-2.00 mm) (0.002-0.05 mm) (<0.002 mm)TextureClass (%) (%) (%)Terrapretaa) 0-10 cm Sandyloam 73 16 1175-100 cm Sandyloam/ 61 19 20sandyclayloamInceptisolsb) 0-10 cm Sandyclayloam 57 14 29c) 0-10 cm Sandyclayloam 53 19 28d) 0-10 cm Loam 39 36 25e) 0-10 cm Loam 44 32 24ChemicalCharacteristicsExchangeableCations Available Organic(me/100g) P CarbonCa Mg Na K Al (ppm) (%) pHTerrapretaa) 0-10 cm 0.20 0.08 tr 0.10 0.71 36 2.2 4.775-100 cm 0.10 tr 0.09 0.10 0.57 15 1.2 4.5Inceptisolsb) 0-10 cm 0.12 0.04 0.04 0.10 1.00 11 2.3 4.0c) 0-10 cm 0.10 0.04 0.04 0.13 1.07 14 2.9 4.4d) 0-10 cm 0.12 0.04 0.04 0.10 1.64 24 3.0 4.1e) 0-10 cm 0.07 0.04 0.09 0.10 1.99 16 3.5 4.0the soil was less dark in color. Sherds were found from surface to bedrock at 108 cm, with a denseconcentration of unusually large fragments, including one complete and several almost intact jars,at 50-70 cm. Locality B may have been the site of a structure. Compared with Site 3/4 at Araracuara,La Sardina is not merely larger but is also much more densely packed with large sherds andarchaeological debris. Disturbance is minimal, and the site was evidently a large settlement withfairly continuous occupation.A terra preta profile from the terrace margin at La Sardina is given in Table 3. In Table 4,analytical data for the profile are provided, together with topsoil analyses from adjacent forest siteswhere similar terrace materials are present but terra preta characteristics are lacking.DISCUSSIONThe terra preta soils described from the Caqueta basin are developed over parent materials ofdifferent origins, namely, sandy colluvium at Araracuara and terrace alluvium at La Sardina. Ineach site, the terrapreta is juxtaposed with Inceptisols which have developed over the same parentmaterial as the terra preta. No consistent drainage variations are evident between the terra pretasoils and the Inceptisols examined. From these conditions and from the frequent occurrence ofartifacts in the terra preta soils, it is concluded that the latter are anthropic in origin and are theproducts of previous Indian settlement. In this respect, the soils are similar to those reported fromthe Brazilian Amazon.Apart from the presence of artifacts, the most prominent feature of the terrapreta in the Caqueta
  • 11. 134 AMERICANANTIQUITY [Vol. 49, No. 1, 1984]Table 5. Soil Colors in the Araracuara Region.Mineral Topsoil Subsoil(0-10 cm) (70-100 cm)a) Terrapreta, Site 3/4 Very dark greyish brown Dark brown (7.5YR4/4) toAraracuara (1OYR3/2) strong brown (7.5YR5/6)b) Adjacent Inceptisols Dark brown (10YR3/3 and Brownish yellow (1OYR6/6) tolOYR4/3) yellowish red (5YR5/8)a) Terrapreta, Site 20 Very dark grey (1OYR3/ 1) Very dark greyish brownLa Sardina (10YR3/2)b) Adjacent Inceptisols Very dark greyish brown Yellowish red (10YR5/6) to light(10YR3/2) to dark yellowish yellowish brown (10YR6/4)brown (1OYR4/4)basin is its coloration, which is usually dark grey to dark brown. Other soil types in the vicinity ofAraracuara commonly display a dark mineral topsoil, but the terra preta is distinctive in that itsdarkcoloration persists into the subsoil. Adjacent Inceptisols commonly display yellowish to reddishsubsoils (Table 5).No general contrast exists between terrapreta and other soils around Araracuara with respect tothe organic carbon content of the mineral topsoil. All values cited fall within the normal topsoilrange for the area of 2.0-4.5%. Terra preta subsoils also display relatively high organic carboncontent, and in this respect they differ from adjacent soil types. The terra preta sites give subsoilvalues of 1.6%and 1.2%organic carbon respectively (Tables 2 and 4), while other subsoils analyzedin the area average 0.4%, with a range of 0.2-0.6% (n = 8).Terra preta soils around Araracuara are also distinctive with respect to available phosphorus.This element, which is present in small quantities in most Amazonian soils (PRORADAM 1979;Sanchez et al. 1982), displays higher values in the terra preta sites. In the latter, topsoil values of71 ppm and 36 ppm are recorded, which compare with an average of 17.5 ppm (range 11-25 ppm)for adjacent Inceptisols (Tables 2 and 4). Improved phosphorus status accords with the conditionsdescribed in the Brazilian Amazon (Smith 1980; Sombroek 1966) and is in general to be expectedon old settlement sites (Eidt 1977; Griffith 1980).In most other respects, the terrapreta soils were not found to be distinctive. Present data suggestthat the relatively high levels of exchangeable aluminum, which arecharacteristic of most Amazoniansoils (PRORADAM 1979; Sanchez et al. 1982), are somewhat reduced in terra preta soils, but ingeneral the latter still display the high acidity (< pH 5.0) and very low base content which characterizemost soils in the region.The Archaeological ContextChanges in pottery style have allowed two successive periods of occupation to be defined for theAraracuara region.The older phase (named Camani) is characterized by small and medium-sized vessels, consistingmainly of simple bowls and jars, predominantly with caraipe (Carneiro 1974) and charcoal temper,and with no decoration apart from brownish or reddish slip (Figure 5). Fire dogs and pottery griddlesindicate the processing of bitter manioc, and carbonized fruits of the milpeso palm (Jessenia polv-carpa Karst) were also found in Camani deposits. Both these foods are still important today, andthe subsistence pattern in the Camani period was probably not very different from that recorded inmore recent times.The time span of the Camani phase is fixed by six radiocarbon dates from three different sites:1815 ? 105 years: A.D. 135 (Beta- 1503); 1800 ? 85 years: A.D. 150 (IAN- 113); 1690 ? 55 years:A.D. 260 (Beta-1504); 1480 + 95 years: A.D. 470 (Beta-1509); 1420 ? 70 years: A.D. 530 (Beta-1505) and 1120 ? 65 years: A.D. 830 (Beta- 1508). Camani pottery has no exact parallel elsewhere,
  • 12. REPORTS 135( ))S0 5 10_ I I cmsFigure 5. Camani pottery from Araracuara.but its closest links seem to be with the plainware component of the Japura style from Mangueirasand other sites some 370 km downstream, on the Brazilian side of the frontier (cf. Hilbert 1968:Abb.83, 4-6).The more recent phase at Araracuara(named Nofurei) has a much wider variety of forms, rangingfrom small cups and bowls to large jars that may have been used for fermented drinks. The fullrange of shapes, including the plainwares, is illustrated in Herrera et al. (1982) and is not repeatedhere. A good deal of Nofurei pottery has elaborate decoration carried out in several differenttechniques: incision, excision, grooving or channeling, impression, zoned punctate, bands of redpaint, and complex designs in which red-painted zones are outlined by shallow grooves (Figure 6).Some of these red-zoned wares also have a fugitive white paint on the background areas, and aretherefore true polychromes. All Nofurei sites produced abundant fragments of manioc griddlesindistinguishable from those of the previous phase, and generally with leaf-imprints on the underside.In excavations on the bank of the river at Araracuara (Site 15) Camani plainwares were strati-graphically overlain by Nofurei sherds, and a radiocarbon date of 1145 ? 80 years: A.D. 805 (Beta-1507) marked the replacement of one style by the other. Two further dates carry the Nofurei styleinto the historical period: 705 + 60 years: A.D. 1245 (Beta-1506) and 350 + 50 years: A.D. 1610(Beta- 1510). Nofurei pottery is clearly a regional variant within the Polychrome Tradition alreadyknown from the Rio Napo in Ecuador (Evans and Meggers 1968), around Leticia in the ColombianTrapecio (Bolian 1972, 1975), and throughout the Amazon basin (Hilbert 1968; Lathrap 1970).
  • 13. 136 AMERICANAN
  • 14. REPORTS 137At Araracuara and at La Sardina, the bulk of the pottery in the terra preta soils belongs to theNofurei style, but at both sites a little Camani pottery was present in the lowest level. These terrapreta soils, therefore, must have begun to form no later than A.D. 800, and probably go backcenturies before that date. This figure is consistent with the single date of 1318 ? 59 years: A.D.632 (P-588) for one of the nearest recorded terra preta sites to Araracuara, at Mangueiras on theJapura (the Brazilian portion of the Rio Caqueta), where the pottery seems transitional between themodelled-incised Barrancoid tradition and the true Polychrome Tradition to which Nofurei belongs(Hilbert 1968; Lathrap 1970:121).Araracuara and La Sardina are at present the only terra preta sites outside Brazil for which soilanalyses are available. Similar deposits may be expected elsewhere in the Amazon region, and thisimpression is confirmed from a search of the archaeological literature and by the comments of thosewith field experience in the area.At La Pedrera, on the Caqueta close to the Brazilian frontier, the upper 40 cm of the archaeologicalstratum was a "tierra negrusca" which the excavator also identified as a terrapreta (von Hildebrand1976:151). The pottery from this locality has clear Barrancoid affinities, as has the Hupa-iya stylefrom a reported terra preta site on the Rio Ucayali (Lathrap 1970:117-120, and personal com-munication). In the Casiquiare-Rio Negro region of Venezuelan Amazonas, Sternberg reports largeterra preta sites with as yet undescribed pottery (in Klinge et al. 1977).Elsewhere, outside Brazil, possible terra preta soils are reported mainly from sites of the Poly-chrome Tradition. At Nuevo Rocafuerte, on the Rio Napo in Ecuador, the deposit is described asa "black sandy loam" (Evans and Meggers 1968:34). In Peru, Lathrap (personal communication)informs us that all the Caimito occupation that covers the shore of Imariacocha consists of terrapreta, though these soils are neither as extensive nor as deep as those of the Central Amazon. Caimitopottery has two radiocarbon dates in the fourteenth century A.D., and, as Weber (1975) notes, isclosely related to the Ecuadorian Napo wares and to Bolians Zebu Complex from the Finca Riverain the Colombian Trapecio. The radiocarbon dates for Finca Rivera range from 920 ? 90 years:A.D. 1030 (1-5776) to 435 ? 90 years: A.D. 1515 (1-5773), showing a good temporal overlap withNofurei (Bolian 1975:47). The final link is provided by a trade sherd of Zebu negative painted ware(or something very close to it) from our excavations at La Sardina.Although unsupported by soil analyses, these reports suggest that the terra preta phenomenonmay be more widespread than is generally recognized. Indeed the scope of enquiry will eventuallyhave to extend to sites outside the Amazon basin in order to encompass, for example, the middenof "tierra negra" at the Saladero site on the Orinoco (Cruxent and Rouse 1958:214-215), or the"sites of ancient villages marked by a deep black soil mixed with broken pottery" from the forestsof the River Corentyne in Guyana (Brown 1876:339). In a ratherdifferent environment, what appearto be terra preta soils have been observed in the Llanos Orientales of Colombia (Pedro Botero,personal communication). For these areas there are no analytical data whatsoever and comparisonsare for the moment impossible.CONCLUSIONSSoils displaying distinctive terrapreta characteristics have been identified on contrasting ripariansites in the middle Caqueta basin of Colombia, and are considered to represent the location ofprevious Indian settlement. The darker color and higher organic and phosphorus status of the soilsare significant characteristics that appear to have resulted from the accumulation of domestic wasteproducts within settlement areas. This accords with the presence of pottery and other artifacts inthe soil. While terra preta soils, once formed, represent favorable areas for cultivation, there is noreason to assume that the soils themselves were originally the direct result of agricultural activity.In general, the Colombian terra preta soils appear similar in origin to those reported elsewherein Amazonia. Consultations with our Brazilian colleagues (vide Acknowledgments) produced aconsensus; in their experience, as in ours, all terrapreta localities are archaeological sites, althoughnot all archaeological sites have terrapreta soils. Some spatial variability occurs in the soils. Intrasite
  • 15. 138 AMERICANANTIQUITY [Vol. 49, No. 1, 1984]variation, for example, is evident in the middle Caqueta basin, as demonstrated by our own researchat La Sardina and the work of Andrade and Botero at Araracuara. Variations also occur betweensites. Thus, some Brazilian terrapreta soils contain significantly higher levels of available phosphorusthan those reported in the present study area, and also display enhanced levels of exchangeablecalcium and magnesium (Falesi 1972; Sombroek 1966). Such variability is to be expected, andpresumably reflects differential rates of accumulation of domestic waste, as well as variations in thelength of site occupance. Because weathering and leaching processes have continued since theformation of individual terrapreta soils, the age and subsequent history of the soils, including thepossibility of later cultivation, will also have influenced their chemical and other characteristics.While terra preta soils can readily be discussed in cultural and pedological terms, the questionarises as to their precise status from a soil taxonomic point of view. As yet, rather few sites havebeen investigated and little comparative information is available on the soil material. Using theAmerican soil classification, Ranzani et al. (1970) have described the Brazilian terra preta as a"plaggen epipedon," which develops as a surface agricultural horizon (U.S.D.A. 1960, 1975). Whilea terra preta is better described in that classification as an "anthropic epipedon," developed at aplace of settlement (U.S.D.A. 1975), the objective of Ranzani et al. (1970) to place the materialwithin a general soil classification is appropriate, since it provides an independent framework forthe terrapreta and also draws attention to the fact that comparable soils exist in other parts of theworld.Although few generalizations can currently be offered with respect to terrapreta soils, considerablescope exists for further investigation of their nature, origin and distribution, as an aid to thereconstruction of Precolumbian settlement and population patterns (Beckerman 1979:555; Denevan1970; Lathrap 1970; Meggers 1971; Myers 1973; Smith 1980). The situation emphasizes once againthat archaeologists should not work in isolation, classifying their potsherds while ignoring the soilmatrix in which these occur. The urgent need now is for more laboratory analyses and for a muchcloser collaboration between archaeologists and soil scientists.Acknowledgments.Acknowledgmentof assistancein the fieldis madeto the Colombianmilitaryleaderofthe ColombianAmazonasExpedition1977,MajorAlbertoRubio,andto his Britishcolleagues,CaptainsJohnSaundersand AdrianGoldsack;also to Ana MariaFalchetti,ElizabethReichelde von Hildebrand,TomasLombo,Julio Morelo,WilliamNieto, ValentinOyola,Dr. JaimeRestrepo,GeoffTancred,Jose LuisVarela,andto ourYucunafriendsat La Sardina.For comment, literatureand informationwe are indebtedto Ulpiano Bezerrade Meneses, Igor Chmiz,OndemarDias,RobertEidt,DonaldLathrap,EuricioTh.Miller,PedroIgnacioSchmitz,MarioSim6es,MarleneSuanoand Peter Paul Hilbert.AngelaAndradeand Pedro Botero made availablethe resultsof their owninvestigationsin the Araracuararegion.None of thesescholarsshouldbe heldresponsibleforanyconclusionswehavedrawnfromtheirdata.ThepalmfruitswereidentifiedbyJesusIdrobo.Forlaboratoryandcartographicwork,we thankMargaretOnwuandClaireWastie.Forpermissionto carryout the researchwe aregratefultothe InstitutoColombianodeAntropologlaandits thenDirector,AlvaroSotoHolguin,and,forotherassistance,to CarlosCaceres,Directorof the ProyectoRadargrametricodelAinazonas.FinancialassistanceisacknowledgedbyEdenandBrayfromtheCentralResearchFund,UniversityofLondon,and bv Brav frnm the British AcademvREFERENCES CITEDBeckerman, Stephen1979 The Abundance of Protein in Amazonia: A Reply to Gross. American Anthropologist 81:533-560.Black, C. A., D. D. Evans, J. L. White, L. E. Ensminger, and F. E. Clark1965 Methods of Soil Analysis (Parts 1 and 2). American Society of Agronomy, Madison.Bolian, Charles1972 An Archaeological Survey of the Trapecio de Amazonas, Colombia. Paperpresented at the NortheasternAnthropological Association meetings, April, 1972, Buffalo, N.Y.1975 Archaeological Excavations in the Trapecio of Amazonas. The Polvchrome Tradition. Ph.D. disserta-tion, University of Illinois at Urbana-Champaign. University Microfilms, Ann Arbor.Bray, Warwick, Colin McEwan, and Leonor Herrera1977 The Archaeology of the Region of Araracuara(Colombian Amazonas): A Preliminary Report. Ms. onfile, Instituto Colombiano de Antropologia, Bogota.
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