ORGANIC MATRICES

Volumen 1 Number 4 Year 2003

2019-11-06T21:34:53+02:00October 26th, 2019|Volumen 1. Number 4. Year 2003.|

VOLUME 1. NUMBER 4. 2003

Structural and Chemical Bone Modifications in a Modern Owl Pellet Assemblage from Olduvai Gorge (Tanzania).

Yannicke Dauphin, Peter Andrews, Christiane Denys, Yolanda Fernández-Jalvo, Terry Williams.

Keywords: BONE, REGURGITATION PELLETS, OLDUVAI, CHEMICAL COMPOSITION, ORGANIC MATRICES

[+info] VOLUME 1. NUMBER 4. 2003 (1 issue)

A modern regurgitation pellet assemblage created by an unknown avian predator from Olduvai Gorge (Tanzania) was analyzed taphonomically and chemically. The combined use of several analytical techniques allowed us to determine some characteristic effects of bone surface modification induced by the predator´s digestive process. Based on these analyses, it is suggested that the predator is Bubo lacteus, Verreaux´s eagle owl. The chemical analyses of the mineral and organic components of the bones show only small changes in composition and proportion. However, the small alterations favour the hypothesis of post-predation diagenetic changes, which may create bias in the preservation of different types of bones.

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Taphonomy of Freshwater Turtles: Decay and Disarticulation in Controlled Experiments.

Leonard R. Brand, Michael Hussey, John Taylor.

Keywords: TAPHONOMY, TURTLE, TESTUDINES, DECAY, DISARTICULATION, BIOSTRATINOMY, EXPERIMENTAL TAPHONOMY

[+info] VOLUME 1. NUMBER 4. 2003 (2 issue)

We conducted an experimental study of the timing and nature of taphonomic processes in turtles that allowed a comparison among different environments. We documented decay and disarticulation of freshly-killed aquatic turtles in controlled settings, including freshwater and seawater aquaria, and outdoor terrestrial settings protected from scavengers. The study area was in hot and dry southern California, with scattered winter rains. We transferred some specimens after 53 days from the terrestrial environment to one of two other environments - freshwater, or an outdoor terrestrial cage - simulating increased rainfall. In water, turtle flesh decayed by bacterial action in three and a half to five months, but insect larvae removed the flesh from terrestrial carcasses within two weeks, leaving dry, desiccated carcasses. Turtles disarticulated most rapidly in water, followed by the high rainfall treatment, then dry terrestrial. The sequence of disarticulation of different bones from the body varied considerably, especially in the terrestrial treatment, but there were some consistent trends. Heads and necks, tails, and limbs tended to disarticulate early in the process. Next the carapace, and lastly, the plastron, disarticulated. Minor weathering occurred on the inside surface of some shell bones in the terrestrial environment. These data provide a basis for estimating maximum length of exposure of fossil turtles before burial and for comparison of turtle taphonomy with taphonomy of other small vertebrates.

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Biostratinomic Patterns in Archosaur Fossils: Influence of Morphological Organization on Dispersal.

Cambra-Moo, O. & Buscalioni, A. D.

Keywords: TAPHONOMY, BIOSTRATINOMY, DISPERSAL STAGES, DISPERSAL SEQUENCES, ARCHOSAURS.

[+info] VOLUME 1. NUMBER 4. 2003 (3 issue)

The dispersal of 122 specimens of fossil archosaurs and lepidosaurians from different localities throughout the world, catalogued as fossil-lagerstätten, has been characterized. The analysis is based on the quantification of dispersal by the evaluation of burial position, anatomical disarticulation, overlap and significant absences of bony elements. Our goal is to identify commonalities of morphological organization, and to reveal dispersal patterns. First, we explore a theoretical space of burial positions, and seek logical alignments of variables in order to understand the sequence of the earliest biostratinomic phenomena. Dinosauria and the basal avian specimens (Archaeopteryx-like organisms) are biased towards lateral burials with crossed forelimbs or hindlimbs. Pterosauria and Ornithuromorpha have ambivalent burial positions, while Enantiornithes and Confuciusornithidae adopt preferentially dorso-ventral burial positions. There is a significantly negative regression coefficient relating overlap and disarticulation-absence. A high percentage overlap corresponds to a high percentage articulation and completeness of body elements, particularly in laterally lying fossils. Conversely, overlap and disarticulation are not significantly related in specimens with a dorso-ventral burial position. Ambivalence in burial positions is associated with singularities in disarticulation patterns. Aves and Pterosauria both diverge from the general disarticulation sequence of diapsids. The results indicate that dispersal has a strong biological component at least in the initial steps of the biostratinomic process.

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Volumen 9. Number 3. Year 2011.

2019-11-06T22:56:49+02:00October 26th, 2019|Volumen 9. Number 3. Year 2011.|

VOLUME 9. NUMBER 3. 2011

Suid Bone Marrow Yields and How They May Influence Resource Choice.

Gillian L. Edwards, Teresa E. Steele.

Keywords: BONE MARROW, FAT, DOMESTIC PIG, WILD BOAR, EXPERIMENTAL ARCHAEOLOGY, TAPHONOMY, WILDEBEEST, IMPALA

[+info] VOLUME 9. NUMBERS 3. 2011 (1 issue)

Marrow is a valuable source of energy, fat, and nutrients that has been exploited by prehistoric and historic peoples across many different environments. Previous experiments on marrow yields have provided new insights into the nutritional value of many ungulates that were important to the diets of past hominins. However, few studies have been conducted on suids. To investigate the caloric value of suid marrow, we broke ten humeri, seven radii, eight femora and seven tibiae of domestic pig and two of each of these elements of wild boar (both Sus scrofa) limb bones using the hammerstone and anvil technique. The marrow inside was removed and dried so that its kilocaloric value could be calculated. In this paper we compare and discuss the kilocaloric yields of males and females, different elements, and different age groups and conclude that, beyond seasonality, body size and age are potential indicators of marrow kilocaloric yields. Further, we compare our data to available data on impala (Aepyceros melampus) and wildebeest (Connochaetes taurinus), and we conclude that these ungulates provided more marrow than suids, and therefore they may have provided more benefits as a food resource.

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Diagenetic Changes in Pleistocene Mollusc Shells of the Patras-Corinth Rift (Greece).

Yannicke Dauphin, Alain Denis, Denis Sorel.

Keywords: MOLLUSC SHELLS, PLEISTOCENE, DIAGENESIS, MICROSTRUCTURES, ORGANIC MATRICES

[+info] VOLUME 9. NUMBERS 3. 2011 (2 issue)

Modern mollusc shells and samples from the Pleistocene of the Patras-Corinth rift (Greece) have been studied to determine the state of preservation of the microstructures. Diagenetic effects are highly variable within the site, within a shell, and within a structural layer. The strongest effects have destroyed the microstructures. Some microstructural changes are correlative of a mineralogical change (aragonite to calcite). The comparison of soluble organic matrices extracted from modern and “well-preserved” fossil shells shows there is a loss of organic matrices in fossil shells even in still aragonitic samples. Moreover, the composition of the organic matrices is also altered. From these data, it appears that diagenetic alterations are still unpredictable. Thus, the only control of the mineralogy of carbonate skeletons used as proxies for palaeoenvironmental reconstructions, to establish tectonic movements, or for dating is necessary, but insufficient.

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Flaked Stone Taphonomy: a Controlled Experimental Study of the Effects of Sediment Consolidation on Flake Edge Morphology.

Metin I. Eren, Andrew R. Boehm, Brooke M. Morgan, Rick Anderson, Brian Andrews.

Keywords: TAPHONOMY, FLAKED STONE TOOLS, EXPERIMENTAL ARCHAEOLOGY, SEDIMENT CONSOLIDATION, GRAVEL, PRESSURE

[+info] VOLUME 9. NUMBERS 3. 2011 (3 issue)

Sediment consolidation can influence both stone flake artifact inclination and vertical displacement. In this paper we present a novel experiment for investigating the effect of sediment consolidation on the morphology of stone flakes. Focusing specifically on the variables of gravel size and pressure, we show that sediment consolidation does not appear to result in the creation of retouched assemblages from nonretouched ones. Bend-break fractures via sediment consolidation did occur at higher frequencies, and as such the occurrence of bend-breaks needs further experimentation to tease out other specific contexts in which they occur. Overall, however, our experimental results suggest that in most cases archaeologists should not be concerned with sediment consolidation altering the appearance of flaked stone assemblages.

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The Taphonomist´s Corner: Isognomon shell concentration.

Juan C. Braga

Keywords

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