Taphonomie et étude de population de Blagoveschensk

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Posté par Tikémi il y a 16 ans

C'est passé inaperçu et ça ne fera pas long feu ici lol, l'article de mon mémoire.

Pascaline Lauters, Yuri L. Bolotsky, Jimmy Van Itterbeeck, and Pascal Godefroit, 2008. Taphonomy and age profile of a latest Cretaceoous dinosaur bone bed in Far Eastern Russia. Palaios 23: 153-162

Abstract : A large dinosaur bone bed has been investigated in the Udurchukan Formation (?late Maastrichtian) at Blagoveschensk, Far Eastern Russia. The observed mixture of unstratified fine and coarse sediments in the bone bed is typical for sediment-gravity-flow deposits. It is postulated that sediment gravity flows, originating from the uplifted areas at the borders of the Zeya-Bureya Basin, reworked the dinosaur bones and teeth as a monodominant bone bed. Fossils of the lambeosaurine Amurosaurus riabinini form >90% of the recovered material. The low number of associated skeletal elements at Blagoveschensk indicates that the carcasses were disarticulated well before reworking. Although shed theropod teeth have been found in the bone bed, <2% of the bones exhibit potential tooth marks; scavenging activity was therefore limited, or scavengers had an abundance of prey at hand and did not have to actively seek out bones for nutrients. Perthotaxic features are very rare on the bones, implying that they were not exposed subaerially for any significant length of time before reworking and burial. The underrepresentation of light skeletal elements, the dislocation of the dental batteries, and the numerous fractured long bones suggest that most of the fossils were reworked. The random orientation of the elements might indicate a sudden end to transport before stability could be reached. The size frequency distributions of the femur, tibia, humerus, and dentary elements reveal an overrepresentation of late juveniles and small subadult specimens, indicative of an attritional death profile for the Amurosaurus fossil assemblage. It is tentatively postulated that the absence of fossils attributable to nestling or early juvenile individuals indicates that younger animals were segregated from adults and could join the herd only when they reached half of the adult size.

S'il y a des gens qui s'intéressent à la tapho quoi lol

Posté par Gigy il y a 16 ans

Wahhhh super intéressant ça! On a a une idée du sens dans lequel le flux a emporté les éléments de carcasses désarticulées? A t'on fait des études de densité et des types d'ossements retrouvés comme cela se fait parfois pour déterminer ce sens.
Théropoda? De taille petite ou moyenne ou alors ce qui serait à attribuer à Tyrannosaurus "luanchuanensis"?

Posté par Tikémi il y a 16 ans

Yep tout ça est dedans lol
Malheureusement les tests stats démontrent qu'il n'y a pas de sens préférentiel (pas grave ça corrobore l'hypothèse de la coulée de boue ;-) ). Je me suis basée sur les travaux de Voorhies pour ça, et j'ai fais les tests avec tous les éléments et avec seulement "ceux plus pratiques" pour déterminer le sens du courant, ça ne change rien.
Pour les Theropoda, on a des dents de tyrannosauroides et des dents de type Dromaeo.

Posté par Pyroraptor il y a 16 ans