Dir. M. Patou-Mathis, P. Tassy
Role des agents climatiques et edaphiques dans la mise en place d'un
assemblage osseux : taphonomie d'un gisement a mastodontes du Miocene moyen
(En Pejouan, Gers)
How do climatic and edaphic agents take part in the setting of faunal
remains : taphonomy of a middle Miocene mastodonts site (En Pejouan, South
Aquitaine Basin, France)
The object of this taphonomic site is to point out the edaphic, climatic
and biological factors which participated in the setting of the faunal
remains at En Pejouan, without any human activity, and low carnivores effect.
The bones of En Pejouan mainly belong to the Proboscidea species Gomphotherium
angustidens (Cuvier, 1817). They were taken from clastic mollasic sediments
(coarse sands), which had got set in a changing fluvial environment during
middle Helvetian. The Astaracian fauna of En Pejouan was first palaeontologically
analysed by L. Ginsburg and P. Tassy. Beside the mastodonts there are small
Bovidae, small Cervidae, Suidae, Rhinoceratidae, few carnivores and very
few Castoridae (number of anatomical elements, and combined minimum number
of individuals). Two paleoecological analyses, based on the mammal association,
draw a wooded savannah landscape (ecological diagramms by Flemming/Andrews/Guerin,
and cenogram by Valverde/Legendre).
Concerning the pre-burial events, the taphonomic and sedimentological
features indicate first that the mastodonts death could have happened under
drought conditions. Otherwise, water was a mainfactor in forming the bones
assemblage. It can be shown, for instance, that two opposite ways of transport
were made by the fossils : the antelopes bones have mainly moved into the
site, whereas the gomphotheres ones have chiefly been under Out-move action.
The bones, which show a high stage of weathering (as defined by A.K. Behrensmeyer),
have stayed on the soil quite a long time, before they were buried. The
breakeage features can result from trampling or sediment packing. Other
post-burial factors, pedogenetic and diagenetic; have modified the bones.
Percolating water has thus destroyed most of epiphyses, and the roots have
let some tracks too.
By such a methodological taphonomic study, many questions about prehistoric
people's food habits, concerning very big mammals such as Proboscidea,
can then be partly answered.
(2) Gerard Klein HOFMEIJER, Faculteit Aardwetenschappen Univerity of Utrecht, Budapestlaan 4, Utrecht, Netherlands
Title: Late Pleistocene deer fossils from Corbeddu cave: implications for human colonization of the island Sardinia. pp.1-436.
Corbeddu on the island Sardinia contains Late Pleistocene sediments bearing numerous fossils of the endemic deer Megaloceros cazioti. The faunal analyses, described in the present study, are restricted to the upper 8 levels of layer 3 of Hall 2 (13.700 to 11.350 y BP.).
In an early stage of the excavation activities in Corbeddu cave, it
was discovered that human activities possibly were involved in the site
formation processes. These processes have been reconstructed based on the
quantitative analyses of the fossil deer assemblages. Also and in particular
in view of the far reaching consequences of the inferred human presence
on Sardinia during the Late Pleistocene, it was found necessary to collect
detailed information from these assemblages, which required the registration
of the three dimensional coordinates of the bones, even of the smallest
fragments. The collected material and the large datatset provide detailed
information about the microstratigraphy of the site, which has been reconstructed
by using a newly developed computer program.
This program enables to distinguish fossil levels by analyzing vertical
density variations. For each reconstructed level the horizontal spatial
distribution, the skeletal element representation, the degree of fragmentation,
the presence of associated elements (both paired and articulating), the
age and sex compositions, and a number of specific damage patterns have
been analyzed. The combination of all taphonomic information makes it possible
to reconstruct the nature of the site formation processes, which include
the type of bone accumulation, and the successive pre-and post-burial modifications
processes. It is concluded that the assemblages cannot have been formed
by natural processes alone.
The performed analyses confirm the earlier presumed activity of humans.
In several aspects the nature of the assemblages is extraordinary compared
to known mainland assemblages found in archaeological context. In the latter,
bones are generally associated with feeding activity, as indicated by skeletal
element selection and bone breakage. In the Corbeddu assemblages this relationship
with feeding activity is less evident. Possibly the use of bones as tools
played an important role.
(3) Ph.D thesis: PAOLA IACUMIN "Abondances isotopiques (13C, 15N, 18O) de mammiferes fossiles : implications pour les regimes alimentaires et les environnements dans la zone mediterraneenne et nilotique depuis 650 000 ans"
Presented on 29 November at the Universite P. et M. Curie (Paris, France) in front of the following committee :
Pr. Louis CHAIX (Archeologie, Geneve, Switzerland)
Pr. Robert E.M. HEDGES (Research Laboratory for Archaeology, Oxford,
United Kingdom)
Pr. Gian Maria ZUPPI (Earth Sciences, Torino, Italy)
Dr. Herve BOCHERENS (Biogeochimie Isotopique, Paris 6)
Pr. Antonio LONGINELLI (Geochimie Isotopique, Trieste, Italy)
Pr. Andre MARIOTTI (Biogeochimie Isotopique, Paris 6)
Pr. Maurice RENARD (Geologie des Bassins Sedimentaires, Paris 6)
Dr. Jean-DENIS VIGNE (Anatomie Comparee, Museum National d'Histoire
Naturelle, Paris)
The main goal of this dissertation was the reconstruction of palaeoenvironmental
conditions in continental area by means of different isotopic measurements
(13C, 15N, 18O) carried out on different compounds of the same samples.
The samples to be studied are fossil skeletal remains of mammals of different
age ranging between Pleistocene and historical age.
The results obtained allow palaeoclimatological and palaeoenvironmental
reconstructions as well as the reconstruction of palaeodiets both in the
case of humans and animals. To assess the reliability of the studied fossils
we have shown the existence of a relationship between d18Op and d18Oc values
of the carbonate hydroxylapatite. The coupled measurements of these two
variables make it possible to monitor diagenetic alterations of fossil
bones and teeth. The carbon and nitrogen isotopic composition of human
and animal bone samples coming from the Nile Valley pointed out the difference
in diet between Egyptian and Nubian populations from the pre Dynastic to
roman period. The isotopic method seems to be quite precise and reliable
in suggesting the presence of foreign specimens coming from different environments.
A direct comparison of the collagen isotopic signals with the oxygen isotopic
composition of hydroxylapatite phosphate and carbonate, allows a better
interpretation of the variations in a temporal sequence. The isotopic measurements
carried out on samples belonging to three mammalian species coming from
a sedimentary sequence of Pleistocene age (33,000 to 13,000 BP) in southern
Italy (Pagglici cave) suggest, for the period between 19,500 to 13,000
BP a climatic improvement followed by a rapid deterioration at 16,500 referred
to Oldest Dryas. The climatic curve obtained corresponds fairly well to
the known sequence of climatic events as recorded by the isotopic curve
obtained from the GRIP ice core, despite the large latitudinal difference.
One of the main problems to be solved for a correct use of this method
for palaeoenvironmental studies is the capability of the skeletal material
to preserve its pristine isotopic composition throught time. The hypothesis
of a relatively fast and large interference of diagenetic processes, at
least in the case of bones, was supported by the results obtained measuring
the d18Op values of herbivore samples from the Arago cave in Sourthern
France.
The time interval covered by our samples was between about 650,000
and 450,000 years BP. The range of values in each stratigraphic level is
quite large suggesting a diagenetic alteration of the samples, probably
favoured by the flow of relatively large amounts of meteoric water.
We can conclude that, in the case of good preservation of the skeletal
material the main goals of the proposed study are essentially fulfilled;
the results look quite encouraging and suggest a wide field of application
for palaeoenvironmental studies in continental areas.
(4)Luis Alcala : Macromamiferos neogenos de la fosa de Alfambra-Teruel Instituto de Estudios Turolenses-Museo Nacional de Ciencias Naturales (CSIC). 554 pp. 1994. (See news of the labs).
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