R. Dechamps's scientific contributions
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Publications (24)
Palaeontological and prehistory studies of the karstic regions of Gabon have led to the discovery of lithic industries (LSA) in two caves. In Paouan cave, a borehole revealed the presence of an upper archaeological level (3900 BP) represented by a thick bed of charcoal and a lower level (5670 BP) with abundant stone flakes and charcoal, including t...
In the rainforest of central-Gabon, the discovery of burnt tap roots dated to 1400-1500 BP provides the earliest evidence of burning associated with ironworking populations, even though the climate may have been slightly drier than it is now. There is an abridged English version. -English summary
The discovery of new fossil taxa in the Miocene of Uganda (Kisegi and Kakara areas) complements and refines the biostratigraphy of the Westeern Rift published in 1991 based on large mammals and molluscs. Correlations to the Mohari Formation in Zaire suggest that it is Middle Miocene and not Lower Miocene as previously thought.
Twenty genera of exceptionally well preserved fossil fruits from 2 stratigraphic levels (Nkondo Formation and Hohwa Member) indicate that during the lower Pliocene the Nkondo-Kaiso region (Western Uganda) was covered in quite humid lowland Guinean-Congolian rainforest. This contrasts strongly with the presence in the lower Pleistocene, in the same...
A rescue excavation of an archaeological structure has yielded potsherds and wood charcoal. A 14C date of 1565 +/- 140 bp (Arc-490) puts the ceramics in an Early Iron Age. Charcoal has been identified. It comes from wood species of poor burning quality. It is thought that most of the woods were used for a magical/ ritual purpose. The ceramics have...
In the middle of the Mayombe forest, remains of smelting, dating from 2110 ± 60 BP are the oldest known traces of the Early Iron Age recognized with certainty in the Congo, and are almost as ancient as those known from Gabon and the Cameroon. The presence of charcoal of woody savanna species, traces of erosion phenomena and the speed at which iron...
Three climatic periods are known in the Congo for the last 40 millennia: the humid Njilian (40,000–30,000 yr B.P.) is followed by the drier Leopoldvillian (30,000–12,000 yr B.P.), and by the humid period of the Kibangian (12,000-recent) which corresponds with the Holocene.Anatomical identification of vegetable macro-fossils found in the Bateke area...
The identification of 117 wood remains from three sampling sites has permitted to reconstruct a middle Holocene rainforest developed on coastal podzols near Pointe Noire. The substitution of this vegetation by the present savana suggests that climatic changes between the old Kibangian (12 000-3000 BP) and early Kibangian (3000 BP - actual) were mor...
Citations
... Clist 1995 : 273, 270) illustrent la présence d'un milieu forestier, où plus tard une savane se développera (Clist 2006 : 148-149). Ceci est conforme avec les 13 C et les dates 14 C sur les MOS des savanes près de Pointe-Noire au Congo qui identifient un couvert forestier d'au moins avant 8000 BP jusqu'au début du LHFC vers 3000 BP (Schwartz et al. : 1414(Schwartz et al. , 1995 fig.3), c'est-à-dire des forêts appartenant encore au « African Humid Period » (Liu et al. 2017 ;Quade et al. 2018). Ce couvert forestier autour de l'estuaire du Gabon n'a pas été depuis impacté par la phase sèche à l'origine de la création des savanes du littoral Atlantique à seulement quelques kilomètres de là (Figure 4, courbes n°1-6 et voir Clist 2006c (Elenga et al. 1996), au site CORAF (Elenga et al. 1992 ;Fabing 1996), et à la tourbière de la Songolo (Fabing 1996 fig.4). ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/279330044301316-1443608880910_Q64/H-Elenga.jpg)
... Fig. 7. Comparison between the 14 C ages obtained from archaeological sites and those obtained from soils (charcoal fragments or total organic matter), compiled from the literature (Gabon, Cameroun, Congo). References: Clist (1990Clist ( , 1997, Holl (1991), Locko (1990), Maret de (1990, Jé zé gou and Clist (1991), Pinçon (1990), Lanfranchi (1991), Oslisly and Dechamps (1994), , Oslisly and Assoko Ndong (2006), Peyrot et al. (2003), Schwartz et al. (1990). Fig. 7. Comparaison entre les âges 14 C obtenus sur des sites archéologiques et sur des sols (fragments de charbon ou matiè re organique totale) issus de la litté rature (Gabon, Cameroun, Congo). ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/273637894783018-1442251766876_Q64/Richard-Oslisly.jpg)
... It can be assumed a priori that identification to species or genus level, especially in large plant families, is only rarely possible. Still, allocation to species level is frequently claimed in publications on charcoal or subfossil wood from Central Africa, whether from soil samples (Dechamps et al. 1988a(Dechamps et al. , 1988bSchwartz et al. 1989;Hart et al. 1996) or archaeological sites (Pinçon & Dechamps 1991;Oslisly 1999;Mbida et al. 2000;Lavachery 2001). In many of these publications, the allocation of charcoal types to species is neither explained nor discussed and the types are only rarely illustrated. ...
... Four δ 13 C profiles are presented in figure 7. The first, Kazamabika 1, is for a soil profile in a savanna in the north of the reserve, which has values between -13 to -18‰, and suggests that savannas have been in place in this site since the middle Stone Age, over 10 000 years ago Oslisly et al., 1997 ;Schwartz, 1997). The gradual decrease in δ 13 C suggests a gradual increase in organic matter from C 3 plants, suggesting that the ancient savannas had higher densities of shrubs or fire resistant trees than the modern vegetation, which is consistent with some ideas about Congolese savannas (Dechamps et al., 1990 ;Schwartz et al., 1996). The second profile, Mont Yindo, a peak at about 680 m altitude on a ridge of forested hills that extends into the northern savannas, shows forest values extending well below a layer of charcoal dated at 3 065±50 years BP, suggesting that this area has been occupied by forest vegetation for several thousand years. ...
... The podzol that forms the bedrock of these peats contains well-preserved root remnants and root pivots implanted in the brown or red alios (Horizon B) and which they traverse vertically. These root pivots have been dated to ca 5800 to ca 3100 years B.P. [6]. This interval corresponds to a still wet Holocene that precedes the shift to arid conditions after ca 3000 years B.P. However, it appears that on all outcrops, the root pivots implanted in the aliotic B horizon do not cross the peaty levels of the swamps that constitute the base of the yellow ochre formation and that are dated between 7205 and 6846 years B.P. [11]. ...
... Regional uplift and transition to a highly fluctuating global icehouse climate led to increasingly arid conditions in the Pleistocene (e.g.,DeMenocal, 1995;2004;Trauth et al., 2005). A Pliocene humid tropical semideciduous forest was replaced by a wooded savanna environment around the Plio-Pleistocene boundary (Dechamps et al., 1992). ...
... During the last few decades, various Holocene swampy soils and deposits of the Congolese coast were studied either in an outcropping position, such as in Loango and Pointe-Indienne, or buried under recent sands of the offshore bar, as in the Kouilou and Songololo estuaries (Delibrias et al., 1973;Giresse and Kouyoumontzakis, 1974;Giresse and Moguedet, 1982;Schwartz, 1985;Dechamps et al., 1988;Elenga, 1992;Elenga et al., 1992). A wet episode of swampy forest with Monopetalanthus is observed between 5800 and 3100 yr BP. ...
... Although some researchers in their wider work on past vegetation in the Congo Basin classify the Plateaux Batéké as a "mosaic of rain forest and secondary savanna" yet without study sites in the plateaus (Lebamba et al. 2009), other paleoclimatic studies from the plateaus suggest ancient origins, providing a variety of ages for these savannas based on evidence from different disciplines and from different sites. In the northern plateaus, from 40,000 to 12,000 years BP, based on the analysis of plant fragments in the soil, the forest-savanna mosaic continued to be present despite climatic variation (Dechamps et al. 1988). From the southern plateaus, based on pollen cores, a history of 24,000 years confirms fluctuations with the most recent phase favouring grasslands over the past 3,000 years (Elenga et al. 1994). ...
... De ce fait, il apparaît fréquemment dans les analyses polliniques. II faut aussi rappeler que ce palmier est d'origine africaine car son pollen ou certains macrorestes (noyaux) ont été retrouvés en plusieurs points d'Afrique équatoriale dans des dépôts remontant à diverses périodes du Tertiaire (Zeven 1964; Dechamps et al. 1992; Maley 1996 Maley , 1999 Maley & Brenac 1998aMondjannagni 1969; etc. voir Maley 1999; Maley & Chepstow-Lusty 2001). Concernant, par exemp le, cette dernière région, un botaniste fort renommé, Aubréville (1937), a écrit que "l'immense palmeraie du Bas-Dahomey serait une formation naturelle simplement aménagée par les indigènes au cours des siècles». ...
... What is most important is that, in the Lastoursville Caves, 2 billion years old rock formation was found and, therefore, the caves developed within it were put forward as contenders for UNESCO World Heritage status in 2005 (Hickendorff 2014). Moreover, the caves also have archaeological significance (Oslisly et al. 1994a, b; Clist 1999), which was another important factor in their nomination for UNESCO World Heritage status in the Mixed (Cultural + Natural) category (http:// whc.unesco.org/en/tentativelists/2059/). The collecting data for these Chilocoris species are as follows: (1) Grotte 1: Grotte de N'doumbou [N' ...
