Terra Preta

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Thesis about Anthrohumox in Brazilian Lowland

1.1 Term: Terra Preta

1.1.1 Terra Preta as Soil Type

The TP is an anthropogenic, fertile soil that developed locally from the infertile Latosol of Amazonia. The numerous ceramic remains of pre-Columbian Indians in the humus-rich topsoil testify to the influence of humans. However, whether primarily the TP existed and the Indians preferred these spots as settlement sites because of their fertility, or whether the Indians 'converted' their settlement sites into TP by means of 'measures' affecting the soil, is still an open questionand will be discussed in Chap. 1.2 and 1.3.

Despite recent pedogenic processes, the TP is to be identified as Latosol or Oxisol in the sense of soil classifications or as having a oxic horizon in the subsoil, since it shows signs of intensive weathering, desilication, sesquioxide enrichment, clay content of > 15%, which consists almost exclusively of kaolinite, etc. are predominantly present. (For the delimitation of the oxic-horizon see Chap. 2.6.2). Characteristic of the TP is the humus content in the upper part and the consequences thereof, such as increased cation exchange capacity, base saturation, acidity, the + black color (name !) etc., and as a sign of anthropogenic influence, the intermingling of the humus-rich horizons with ceramic and pottery fragments. The other specific characteristics of the TP are discussed in detail below (see Chap. 6).

Instead of a description of the TP, reference is made to the TP representative profiles SP 1 / 2 / 4 - 9 in Chap. 3.9 and the mean representations in the data band of this thesis (p. 42-97).

A scientific definition of TP within the framework of the 7th Soil Approximation is given in Chap. 2.6.2 (Anthrohumox).

Great differences were observed from one TP occurrence to another during field work. The soil type 'Terra Preta' must therefore be viewed as a summary of similar soils rather than as a term for the soil type with largely identical properties, as it is known from Central Europe, for example. 'TP-type' soils share some important characteristic properties and dynamics. However, they can differ in other properties, such as grain size composition (there are clayey and sandy representatives), concretion formations (see Profile SP 0 and Chap. 3.4.1). This raises the question of a definition of the term 'Terra Preta'.

1.1.2 Definition of 'Terra Preta'

The TP can therefore be defined as a Latosol with a strong to very strong humus content in the topsoil with over 13-14% organic matter, sometimes up to over 20%, in the top centimeters, but without hydromorphic signs. Latosols, on the other hand, usually only have a content of less than 10%, usually even much lower (see Chap. 2.6.5). However, since in the Latosol the organic substance decreases very quickly downwards due to the rapid mineralization (at a depth of 50 cm on average only ca 1.3%), in the TP there is stable humus down to average depths of approx. 1 or even 2 m exists (at a depth of 50 cm, e.g. 5.1% organic matter), the humus content at a medium depth serves better as a demarcation criterion.

Based on his field observations (see Chap. 3.5) and literature reviews (tab. 4 in Chap. 6.3.2), the author therefore proposes only speaking of TP if > 2% or > 2.5% organic matter is present (equivalent to 1.2-1.5% C). In the field, this is particularly evident through the dominant dark to black colors of the TP in the upper decimetres (according to the Munsell scale value values ​​of < 5 in the upper 1 meter) compared to the reddish to yellow colors of the latosols (value 6 or 7). An experienced observer is therefore able to estimate the content of organic matter relatively precisely based on the intensity of the black color and in this way to distinguish TP from Latosol or to locate the center of a TP site. In comparison to ectropic soils, this assessment can be made more accurately, since the latosols are essentially more 'homogeneous', i.e. without recognizable horizons, their humus content is lower and the light background color contrasts more strongly with the dark humus colour than in the + browned horizons of the ectropes. The author’s field observation and mapping obtained from this corresponds to the later analysis data.

Secondly, for the existence of a real TP, anthropogenic influence is necessary, which is always associated with the appearance of ceramic remains. This is attested to by other authors as well as our own field observations. The center of the strongest accumulation of humus always coincides with that of the strongest ceramic trimmings. In my opinion, it is sufficient as a condition for the required TP definition if pottery can be found anywhere in the discussed site. These do not necessarily have to occur in the entire area with the higher humus content (see also Chap. 3.5.2, loc.1).

Thus, the two prerequisites for the existence of a TP are:

1.1.3 Terra Preta Terms to Reject

In the adjacent area, various transitional forms from TP to Latosol occur, which often exceed the actual TP area by a multiple (see Chap. 3.6). However, due to their weaker development - often only the upper 10 cm humos - these soils are no longer to be regarded as TP sensu strictu. A profile chain of this kind examining soil association consisting of 5 soil profiles at a distance of approx. 500 m was recorded in the field (see Chap. 3.5.2, loc. 11) and corresponding samples were taken, but these were not analyzed, so that the corresponding discussion is not necessary. The occasionally occurring term 'Terra Mulatta' (Sombroek 1966, p.175; Franco 1962, p.17) as a transitional soil type of TP to Latosol should not be used as long as its own characteristics are not proven can, it is unclearly delimited and not sufficiently investigated.

Likewise, the term 'Terra Preta Comum' (Dubois, FAO, orally) to describe an allegedly non-anthropogenic, i.e. pottery-free, but nevertheless rich in humus, black latosol of unknown, natural genesis and distribution should be rejected as doubtful. During field work by the author all relevant information turned out to be anthropogenic (see Chap. 3.5).

1.1.4 Terra Preta as Research Approach

If it were possible to use this genetic process for TP formation in a controlled manner over a large area, then a large-scale improvement of soil in Amazonia without premature exhaustion of the soil would be conceivable. It can therefore be described as a 'long-term goal of TP research' to identify and understand the development of Latosol into a soil type rich in humus and nutrients.

The possibility of using larger areas intensively for agriculture, since a leaching or depletion of the nutrient supply was not observed in the TP - in contrast to the Latosol - would undoubtedly be an advantage for the local population. Higher and particularly constant crop yields promise a better nutritional and (probably also) income situation for the people, some of whom live close to or below the subsistence level, and from this a development of the infrastructure of the area (but see Chap. 7).

Science is thus faced with the problem of analytically recognizing processes that people in earlier eras already used for themselves on the basis of their wealth of empirical experience, but whose knowledge has now been 'lost'.

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1.2 Status of Research

1.2.1 Earlier Research

'Terra Preta' - or at that time also called 'Terra Cotta' - was mentioned by name for the first time in 1871 by Ch. F. Hartt. Although a geologist, he describes in detail the found ceramics from former settlements of the Indians and thus also TP deposits on Ilha do Marajo, on the lower Amazon and on the lower Tapajos. Also mentioned for the first time is the Santarém TO complex, which extends ca 50 km W and E of Santarém and about 70-80 km S. According to this first observation, it allegedly only occurs in the recent alluvial lowlands along the banks and on the edges of the high plateau a few kilometers away (Hartt 1885, p.12), as was also observed by the author, but not exclusively on these places (see Chap. 1.3 and 3.6).

Hartt's observations are limited to the 'discovery', i.e. the first mention of this phenomenon in the scientific literature, and a brief outline of the regional distribution in the region around Santarém. He suspects that this site attracted the Indios due to its primary, i.e. soil genetically determined fertility, who built their settlements on it and tumbled it intensively, and that this explains the large number of pottery remains in the TP ;ren be. Because even for him, based on the many ceramic finds, there was no doubt about the close connection between TP and Indian settlements.

Catter took up Hartt's hint and also looked for some TP deposits in the Santaremer area and analyzed some samples (1903). According to him, the TP are 'joint flooding of organic and inorganic detritus of the rivers that used to be at a higher level' (Zimmermann 1958, p.51).

The TP then fell into oblivion again, but reappeared in the mid-1920s in geological and mineralogical mapping without further discussion (Serv.Geol.Min. 1926, p.5-30).

During the work of a boundary commission, Barbosa de Faria examined the TP in 1928, named a series of 2-4 ha large deposits on the lower Trombeta (see Chap. 1.4: Barbosa d.F. 1940; 1944; 1946) and, like Hartt, was of the opinion that the The primarily caused, high fertility of the TP only secondarily attracted the Indians, who used it as a ritual, which explained the constantly broken ceramic pieces (Hilbert 1955, p.12, 18). He concluded this from some observations of religious ceremonies in which large quantities of fired pots and vases were destroyed (e.g. Salas 1946, in Ranzani et.al. 1962; see also below).

Barbosa the F. considered the TP to be + organic filling of former lakes and thus of sedimentological ('geological') origin (Hilbert 1968, p.268), elsewhere he also considered the possibility of volcanic rock sedimentation (Hilbert 1955, p.13).

1.2.2 Research by Archaeologists and Ethnologists

Since that time, the term 'Terra Preta do Indio' or 'Terra Preta' has been used repeatedly by archaeologists and ethnologists. They were involved in the exploration by the high correlation of archaeological sites with TP deposits. Because with a few exceptions, such as the Sambaquis shell heaps on the Atlantic coast (Palmatary 1960, p. 25ff) and a few pure 'fishing villages' directly on the banks of the rivers (Nimuendaju 1949, p.103; Hilbert 1968, p.269), all archaeological finds were made in TP.

According to Sternberg, there is an infallible correspondence between TP and archaeological sites (Hilbert 1968, p.44) or is the 'TP ... in all cases identical to archaeological sites' (Hilbert 1968, p. 28) or 'na terra preta, ha careta' ('where there is TP, there is also pottery'; Barbosa d.F. 1944, in Baldus 1951, p.2) or there is 'none former Indian settlement ... which is not on TP' (note by Nimuendaju, in Hilbert 1955, p.16). The equation of TP occurrences and archaeological sites in the compilation in tab. 3 must therefore also be explained.

The most thorough investigations by an archaeologist come from Nimuendaju, who worked in the Santarémer area from 1923-26 and localized 65 individual TP occurrences there, mainly on the Terra Firme (Nimuendaju 1949, p. 102; see Chap. 1.4 with map, fig1/2). He reported a number of interesting observations, some of which could also be confirmed by the author, such as the exclusive occurrence of TP on hills - therefore the theory of TP genesis can be supported by organic material washed together (see below) can be excluded -, the identity of the soil texture of TP and source soil, the small size of the TP deposits (mostly < 200 m in diameter) and the thick horizons with 'settlement remains' as indications of a very long settlement by the Indians . Other observations, such as their proximity to drinking water in the form of rivers or dug wells or the construction of old, approx. 1 m wide, straight 'Indian roads' between the individual TPs, could not be confirmed (Nimuendaju 1948; 1949, p.102 ff; 1960, p.18 ff; Hilbert 1955, p.15 f; Baldus 1951, p.2f).

In his view, the TP are the 'result of the long and consistent presence of numerous Indian groups in the same place' (Hilbert 1968, p.268). He is thus the first author to postulate an exclusively anthropogenic genesis of TP.

Other archaeologists who dealt with the TP include Meggers and Evans (1948; 1957, p.177 and others), who report on partly sandy TP on Ilha do Marajo in contrast to the purely clayey ones from Belterra, further Palmatary (1939; 1960, pp.18-25 above all) as the pottery and archeology expert of Santarém and Hilbert (1955; 1968). As part of his extensive description of the archaeological sites and cultures, which for the first time encompasses the entire Amazon region, he goes into detail about the appearance of the TP and distinguishes between two 'types' - a distinction that is neither made by the author nor by literature notes or Analysis results could be confirmed: The so-called 'hot' TP is light and loose and not very suitable for agricultural cultivation, while the 'cold' TP is firm and moist and suitable for cultivation (Hilbert 1955, p.15). It is not clear what the difference is between these two TP types, whether they are just different types of soil.

Here, too, the constant proximity to watercourses or open lakes is emphasized, as well as the clustered occurrence of the deposits and the relationship between the abundance of shards and the intensity of the TP: the more pottery there is, the deeper and darker the TP; as this - albeit with exceptions - could also be confirmed in the Belterra area (see Chap. 3.5.3).

They are to be found preferably in the Serras at the highest points, on the banks of the Amazon, where they form a steep bank, but is also the most eroded, and on the escarpments of the Terra Firme , such as in Belterra. In addition, Hilbert as well as Meggers and Evans (1957, p.175 et al.) and the author were able to find strongly hardened, but not concrete, possibly burnt lumps of clay whose purpose or origin is still completely unclear (Hilbert 1968, p.93).

The large number of ceramics broken into the smallest parts and the complete absence of larger pieces or even entire objects can clearly be traced back to deliberate destruction (oral communication from Frickel, Hilbert 1955, p.18). This can be explained in several ways: The possibility of religious orgies has already been mentioned. Another cause for the high degree of destruction is that when the Indians were expelled and exterminated by missionaries in the spirit of 'Christianization' (Hilbert 1955, p.18) or later settlers due to superstitious Fear of the Indians destroying the pottery (Palmatary 1960, p.24).

It seems more likely, however, that the Indians themselves - as still observed today in Amazonian retreat regions - burned down their huts after tribal feuds, in the event of deaths (Hilbert 1955, p.18) or after abandoning the settlement area during shifting cultivation and the ceramic dishes broke, which was later further destroyed and crushed by the deep-rooted cassava plants when the land was used again for agriculture (Palmatary 1960, p.24).

1.2.3 Current, Especially Brazilian Research

More recent works on the TP are only available from Brazil, mostly by geographers and soil scientists. In 1948, Gourou examined the morphology of the region around Santarém-Belterra, discussing in detail the TP and theses of its origin and agreeing with Nimuendaju's thesis, according to which the TP was mainly created by the long-lasting settlement by the Indians (Gourou 1949 , p.376 ff; Falesi 1972, p.37).

Franco (1962) wrote a short research paper about TP deposits of Belterra and their possible origins. He described the TP as the over-sedimentation of the numerous depressions periodically filled with water (so-called Depressaos Fechados: see Chap. 3.4.1), with organic material, favored and partly filled with shards by the sporadic settlement of the Indians on its banks.

He thus comes back to the thesis Barbosa d.F. However, this is contradicted by the observations by Hilbert, Baldus, the author and others that the TP mainly occurs in morphologically exposed places, such as on the edges of the plateau (see Chap. 3.4.1 and 3.5.3). From these observations alone, Franco's thesis cannot be verified!

The 'lens-shaped' character allegedly of all TP localities is mentioned here for the first time (identical to the shape of the other hollow forms): Round, without convex elevation, deepest in the middle, towards the escarpments less deep (see fig. 18 in Chap. 3.5.2), with the transition zone of the so-called 'Terra Mulatta' (see Chap. 1.1.3). That this is not so much a decrease in thickness from the center to the escarpments, but rather in intensity, such as the humus content, was observed in Belterra (see Chap. 3.5). In addition, the 'lens-shaped', round shape is very often caused by morphological influences such as escarpments, banks or the like (e.g. site 1).

In the same year the first pedological analytical work on TP was published, carried out by Ranzani et.al. Samples were taken from two soil pits in the Santarém region and analyzed for some chemical standards (C, N, exchange capacity, pH, etc.). Notable here is the low value of less than 0.02 meq exchangeable K/100 g and the increasing free iron content (Ranzani et al. 1962, p.9; cf. Chap. 6.8.9 and 6.12.2). The origin of TP was treated here as a Plaggen-Epipedon applied to the Latosol and would therefore supposedly be comparable to the European Plaggen soils.

This comparison has to be contradicted for various reasons (see also Chap. 1.3):

Also according to the 7th Soil Approximation, the TP is neither to be addressed as 'Plaggept' nor as 'plaggic' (Soil Survey Staff 1960, p. 35; see Chap. 2.6.2).

In his detailed work on the Amazonian soils, Sombroek also addresses the phenomenon of TP (1966, pp. 158 f, 174-176, 252-256).

Here he describes the fact, already known from the literature, that the TP can be found primarily on Pleistocene terraces, on the Planalto but only on the escarpment or near the river; often in the vicinity of today's cities, so the TP plays an important role in settlement history (see Chap. 1.4). Because of the identity of the texture, clay mineral composition and subsoil of TP and the surrounding Latosol, he rules out any possibility of origin other than the anthropogenic one (ibid., p.174 f).

What follows is the most exact chemical-analytical description to date and its discussion (ibid., p.252-256). In the relation between the C content and the T value of the cation exchange capacity, a perfect, linear correlation could be established, with the T values being almost twice as high as in the latosols.

Further pedological-analytical work has since been carried out by the state agricultural research authority, the former IPEAN (Instituto de Pesquisas e Experimentacao Agropecuaria do Norte) and the current EMBRAPA (Empresa Brasileira de Pesquisa Agropecuaria) carried out in Belem (EMBRAPA 1975; Falesi 1967; 1970; 1972; 1974; IPEAN 1970; Rego et.al. 1978; Vieira 1971; et.al.). Profiles were created in the TP and analyzed analytically, but mostly only for simple, quantitative statements and without further discussion of these contents, so that based on these values there is a quantitative characterization of this soil type, but this cannot be statistically verified and therefore not can be used for a further investigation of the dynamics (see also Chap. 6.3.2, 6.4, 6.5.2 and others).

Falesi puts forward the hypothesis that the round Depressãos Fechados (see above and Chap. 3.4.1) are the last small remains of the mighty, tertiary, Amazonian inland sea (see Chap. 2.1.3), in which, after its drainage to the Atlantic, water and thus aquatic flora and fauna could remain for a long time, which were later broken down and humified and today represent the TP humus (Falesi 1972, p.38 ; 1974, p.213).

The TP plays only a subordinate role in these investigations by the Brazilian government agencies due to its small area and thus its negligibly small percentage of the soils in Amazonia and is therefore usually only used in connection with general compilations of Amazonian soils listed (oral communication from D.d.Santos, EMBRAPA). The fact that the conservation of humic substances and organo-mineral complexes, despite extreme weathering conditions, may provide information about interesting soil dynamics is not taken into account by the Brazilian experts in their possible conclusions for soil improvement.

Finally, the work of the hydrologists Sioli and Klinge should be mentioned, who also trace the formation of TP back to an old culture, 'which, through the enrichment with organic substances from the possibly only during the soil use has itself created podzolic horizons comparable to those of Northwestern European ash soils' (Sioli and Klinge 1961, p.206). They are thus clearly of anthropogenic origin, since the high content of the TP of phosphorus and P-acids, which can originate from the breakdown of the bones (Falesi 1974, p.213), in contrast to this in natural Amazonian soils is not occurs (note by Klinge, in Hilbert 1968, p.269).

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1.3 Models of Development

As an abstract of the field observations listed above, the frequent occurrence of TP can be found

The often exposed situation on hills with visibility to 3 or 4 sides (Mayntzhausen 1912, p.462, in Baldus 1951, p.3; see Chap. 3.7.1), never below the line of the highest water level (Hilbert 1955, p.13), and also the proximity to drinking water places allow the TP to appear at localities preferred by Indians as settlement sites. The actual, quite small TP occurrences of mostly less than 1-2 ha in size can either be completely flat (Franco 1962) or as convex elevations, especially in the lowlands (Meggers and Evans 1957; oral comm. from Erneston, EMBRAPA), tower over the area (see Chap. 3.5.3). The TP occurrences on the most exposed places (in the varcea on hills, on the Planalto at its escarpment) predominate.

The deposits are + round and always end in a + wide transition zone, sometimes kilometers wide, to the surrounding latosol from which they originally emerged. Slightly humic horizons are often found at a depth of 1-2 m; below that, the TP is identical to the Latosol.

The following theories of genesis have been mentioned so far:

The non-anthropogenic sedimentation theories have to be rejected because of the frequent occurrence of TP at exposed and thus erosion-prone sites, but not at sedimentation-favored sites. Just note the extreme spur position of the investigated site 'Chico Alfredo' near Belterra (see Chap. 3.7.1), which excludes the above theories of sedimentation! The TP horizons, which are very heterogeneous in terms of volume, also contradict these theories (see Chap. 6.1.5).

The fact that Depressãos Fechados are often close to TP and have a similar shape does not justify the assumption of (sedimentation) theses that bring them together.

TP is therefore clearly of anthropogenic origin!

In the previous chapter (1.2.3) it was proved - mainly based on the occurrence of the same (geological) strata in Latosol and TP and the gradual transition of the Ah into the Box - that the TP is not a sod soil, i.e. an application of allochthonous + organic material. Rather, in situ there must have been a supply of human urine and faeces, leftover food, leftover fish, etc. (possibly + precomposted), thus an accumulation of organic material., phosphates, Protein compounds etc. on and in the local latosols.

Smoldering fire may also play a role in the formation of charcoal, as is particularly evident in the SP 6 profile (see Chap. 1.5.2 and 3.9), but also observed in the other TP profiles, a role in TP formation.

The fact that the influence of the Indians lasted for a very long time can be deduced from the following extrapolation: In the investigated TP area of 'Chico Alfredo' (see Chap. 3.5.1 and 3.7.2) of 0.65 ha, per pit of 2 sqm area 100-200 ceramic fragments of over 4 cm2 size found. This results in a number of several 100,000 (approx. 400,000-600,000) ceramics for the entire site or - in relation to the pottery size - a number of several 1000 (approx. 4000-8000) pots. Such a production can only have taken place within many generations or even hundreds of years at this point.

After such a clarification of the TP genesis, the question of how the Indians influenced the latosol there can only be clarified by ethnological fieldwork. Some Indians in very remote areas are said to still form TP today (Falesi orally; see Chap. 1.4, pt.23).

From a pedological point of view, the dynamics and stability of the humus compounds and the inorganic and organic distinction from latosol are of particular interest.

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1.4 Terra Preta Occurrencies

Within the framework of the cited archaeological, geographical and pedological work, prospective work was also carried out on TP localities, on the other hand there are also references to the occurrence of TP in non-specialist literature. Based on such literature notes and descriptions of the TP, an attempt is made here for the first time to compile a regional list of TP occurrences. It should be emphasized, however, that such a compilation of the regional distribution can only be extremely imperfect, and even presumably only describes a small part of the TP localities that exist at all. Because of the difficult terrain and climatic conditions, one can only speak of very little pedological exploration of Amazonia (see also Chap. 3.2).

Since exploration of the terrain has always been carried out from large rivers, most of the known deposits are in the immediate vicinity of the Amazon or its large tributaries. Only recently has exploration started, also from smaller rivers and from newly built roads, so that the discovery of TP can also be expected away from the large currents.

Although most of the literature focuses on the lower Amazon region, Hilbert (1968) shows that a large number of TP occurrences in the Amazon lie between Manaus and the Peruvian border. Furthermore, a short literature compilation of research work in the W and NW Brazil-external area is given here. Accordingly, Sr. Sanchez from the Military Geographical Institute of Lima, Peru, spoke of TP-identical soils (with a high content of organic matter and ceramic artefacts) in the Peruvian lowlands (pers.mdl.mitt.) . So there is no doubt that TP also exist in Peru, Equator, Bolivia, probably also in Colombia and the Guianas.

Baldus (1951, p. 1-16: N-Parana), Mayntzhusen (1912, p. 462: at the Alto Parana), the research institute IPEAN (Falesi 1970, p. 107: in Rondonia) and others report about TP sites in more southern part in Brazil. However, statements by D.d.Santos, EMBRAPA (orally) and Sombroeks contradict this, since in Rondonia or in S-Brazil, because of the more nomadic behavior of the tribes there - in contrast to the sedentary behavior of the Tupi and Aruak tribes of Amazonia - could not or have not developed any TP (Sombroek 1966, p.176).

Without doubt, however, the main area of distribution of the TP is the Amazonian lowlands, while it is much less common in the peripheral regions. However, whether this is due to different parent rock, different climatic conditions, other Indian tribes with different ethnic behavior or to completely different influences has not yet been clarified.

The following compilation of all TP occurrences mentioned in the literature so far is broken down by state and by northern or southern location to the Amazon. It serves as the basis for the map below (fig.3). Very imprecise location information is indicated by brackets around the relevant reference.

Interactive map of TP sites in Amazonia


1.4.1 Terra Preta Sites in Amapá

Listing of Terra Preta sites known from literature in Amapá

1.4.2 Terra Preta Sites in State of Pará (N of Amazon)

Listing of Terra Preta sites known from literature in State of Pará (N of Amazon)

1.4.3 Terra Preta Sites in State of Pará (S of Amazon)

Listing of Terra Preta sites known from literature in State of Pará (S of Amazon)

1.4.4 Terra Preta Sites in State of Pará (N of Amazon)

Listing of Terra Preta sites known from literature in State of Pará (N of Amazon)

1.4.5 Terra Preta Sites in State of Pará (S of Amazon)

Listing of Terra Preta sites known from literature in State of Pará (S of Amazon)

1.4.6 Profile Description of Sampled TP and Latosol Profiles

AmapaPara NordPara SuedAmazonas NordAmazonas SuedWorld: Click on region

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1.5 Age of Terra Preta

Since the origin of TP is anthropogenic (see Chap. 1.3), the history of the - especially pre-Columbian - Indians can provide information about the age of the TP. Apart from that, only the 14C method still exists for dating, as it was sometimes used (see below). Other dating options such as dendrochronology, stratigraphic methods or the like were not carried out so far.

1.5.1 Dating Based on Field Observation

The large number of TP occurrences and pottery suggest a very high population density, which - considering today's very low population density - seems at first impression incredible.

But historiography points to other facts here: Orellana, the first person to cross the Amazon valley in 1541, had noticed the size of the settlements. The banks were heavily populated at that time. Heriarte was also astonished by the strikingly high population density (Heriarte 1874, in Hilbert 1968, p.24).

A dense settlement in the region of Santarém existed mainly until 1639, when thousands of Indians were driven away as slaves by the Portuguese, killed or driven further inland (Markham 1859, in Hilbert 1968, p.24; see also Chap 2.7). 'Towards the end of the 17th century ... the once powerful tribe at the mouth of the Rio Tapajos with its numerous villages further inland [which undoubtedly included the later Belterra] was through the slave hunt as good as disappeared from the earthquake' (Nimuendaju 1953, p.53).

This represents a possibility of dating the minimum age: In this large area of Santarém there is a high degree of certainty that the minimum age of the pottery shards found and thus also of this soil is 300 years.

Haberland gives 500 years as the possible upper age limit for these clay vessels (1963, p.213).

It remains to be seen whether this is limited to the uppermost, most developed horizon styles. There is no doubt that this epoch was preceded by older cultural styles as well as earlier TP formation periods.

The fact that there are no other relics of an earlier settlement apart from the TP should not come as a surprise. Due to the weathering and vegetation conditions, former dwellings are quickly overgrown and destroyed by secondary forest (see also Chap. 2.5.4).

1.5.2 14C Dating

14C dating of organic material in the TP should be more exact. Here, however, there is a risk that the measured pieces of charcoal and bone later got into the TP containing them or were contaminated by younger humic substances and thus indicate a younger age (see see Chap. 4.11, there also the principle of the 14C measurement). Only the archaeological objects themselves are safe.

The annealing agents (added, non-plastic particles that prevent shrinkage during drying or cracking during firing) provide Cauixi, a freshwater sponge up to 30 cm in size, or gray ash powder from a tree bark, the organic matter necessary for 14C dating.

With this material, Sternberg dated TP finds from the island Careiro (see Chap. 1.4, pt. 37) to an age of 1075 + 150 years B.P. (1956, in Hilbert 1968, S.45).

Further dating amount to 800 years B.P. (at Coari, pt. 57 in Chap. 1.4), 1100 years (at Paredao, pt. 38), 1200 years (at Coari, pt. 57), 1200 and 1300 years (at Caiambe, pt. 59), 1300 years (at Mangueiras) and 1500 years (at Manacapuru, pt. 41) (Meggers and Evans 1957; in Hilbert 1968, p.47, 256).

Thus, the old age of many TP floors is verified.

At the field work in Belterra (see Chap. 3) samples in the form of pieces of charcoal were taken from profile SP 6 from a depth of 60 cm and 120 cm specifically for age dating. The larger ones were particularly interesting because of their shape (always oblong, rectangular, with a flat front and back), their size (up to 20 cm long) and their relation to one another.

They are likely to be anthropogenic-allochthonous.

The comparison suggests that they were logs to sustain a smoldering fire, similar to the earth-covered charcoal piles of early Europe. The profile SP 6 is at a depth of ca 60-130 cm not typical for TP, outliers were found in this depth range for most elements and parameters.

At shallow depth, however, it is considered undisturbed with TP-typical contents of C, N etc. This indicates that these 'chunks of wood' were not later added into the TP.

It can be assumed that they are more causally related to the development of TP (see Chap. 1.3 and 1.4, pt.59).

In addition, the very light colors in the immediate vicinity of the pieces of charcoal indicate burning and thus strong heating of the soil.

The two samples mentioned above were treated, i.e. above all freed from contamination, and checked for their age at the Institute for Radiohydrometry of the GSF (Society for Radiation and Environmental Research) in Neuherberg, Germany using the 14C method examined (see Chap. 4.11). It turned out:

Despite the not inconsiderable difference of ca 500 years between the two samples, based on field observation (directly one above the other, the same common bright color ring of clay around the two sample sites), it can be assumed that they originate from the same time.

When considering the specified variances, this is by no means impossible. The area of overlap of the two samples at 2 s is at a time between 150 BC and 100 AD.

The origin of the local TP, in particular profile SP 6, is therefore most likely to be dated to the epoch around the turn of the era, but it can also be dated with a certain probability between 800 BC and 500 AD.

However, it has been shown in Chap. 1.3 that TP was probably created over many centuries.

The aim of such age dating should not be an exact historical fixation, but merely the proof of a TP that is many centuries or even millennia old or the extremely long-lasting stability of the humic substances, cation adsorption and resistance to leaching.

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1.6 Archeology

Since the pre-Columbian Indians play an important role in the emergence of the TP, their most important, different epochs will be briefly discussed. Statements about the pre-ceramic Indians of the Amazon region - hunters and gatherers - must be very questionable; remain earthy, since almost nothing has survived from this time of the settlement of Amazonia. Only a few hammer, arrow and spearheads as well as shell heaps (Sambaquis) were found from this period, including in the interior near Santarém (Hartt 1885, p.1ff).

We only have more precise knowledge about the Indian population since they introduced the manufacture of ceramics. Four different cultural phases could be identified here, which successively, but independently of one another, have different characteristics in the cultural and ceramic tradition. In this way, a relative dating and differentiation is possible with comparative methods and with stratigraphic findings within an excavation site.

The four identified cultural phases are:

In all eras the indigenous population must have been able to form TP.

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Last updates: 2007/2022