1,720,994 research outputs found
The long–term survival of bone: the role of bioerosion
No full textFossil bones (N = 350) spanning more than 350 million years, and covering a wide range of depositional environments, were studied to compare the distribution of microbial destruction features in fossil bones with previously published data sets of bones of archaeological age. The distribution of bioerosion in fossil bones is very different from that found in bone from archaeological sites. Fossil bones typically show little or no bioerosion. Under normal conditions, if a bone is to survive into the fossil record, then rapid bioerosion must be prevented (or halted). This conclusion suggests that early post mortem processes,such as the mode of death, influence the potential of any bone to survive into deep time
Stable isotope analyses of collagen in fish scales: limitations set by scale architecture
No full textComparisons between the stable isotope composition of carbon in collagen excized from juvenile (freshwater) and adult (marine) portions of scales from Atlantic salmon Salmo salar demonstrated that c. 75% of carbon analysed in the 'juvenile' portion of the scale derives from later formed collagen. Scale collagen analyses were effectively restricted to the last season of growth
Trace elements in modern and ancient bone (in Phosphates: Geochemical, Geobiological, and Materials Importance, Matthew L. Kohn, John Rakovan & John M. Hughes, editors)
No full textRare earth elements in Solnhofen biogenic apatite: geochemical clues to the palaeoenvironment
No full textRare earth element (REE) concentrations in biogenic apatite samples (coprolite, bone and soft-tissue) were used to investigate the environment of deposition of the celebrated Solnhofen fossil Lagerstätten. The measured REE patterns are similar between different localities, lithologies (flinz, fäule) and levels in the Upper Solnhofen Plattenkalk, suggestive of a stable REE supply during deposition. The behaviour of cerium in the Solnhofen samples implies that bottom water conditions were not anoxic, and variations in the cerium anomaly can be explained by differences in burial rate. These results provide further geochemical support for current depositional models [Barthel, K.W., 1978. Solnhofen: Ein Blick in die Erdgeschichte. Ott Verlag, Thun.; Barthel, K.W., Swinburne, N.H.M., Conway Morris, S., 1990, Solnhofen. A Study in Mesozoic Palaeontology. Cambridge Univ. Press, Cambridge.] that propose that extra-basinal processes are responsible for the interbedded nature of the Solnhofen deposits, rather than intra-basinal processes such as water turnover events
Diagenetic origin of REE in vertebrate apatite: a reconsideration of Samoilov and Benjamini, 1996
No full textThe effect of growth rate on tissue-diet isotopic spacing in rapidly growing animals. An experimental study with Atlantic salmon (Salmo salar)
No full textThe difference in isotopic composition between a consumer's tissues and that of its diet is a critical aspect of the use of stable isotope analyses in ecological and palaeoecological studies. In a controlled feeding experiment with the Atlantic salmon, Salmo salar, we demonstrate for the first time that the value of tissue-diet isotope spacing in nitrogen in a growing animal is not constant, but varies inversely with growth rate. The value of tissue-diet isotopic spacing in N reflects N use efficiency. Thus, in salmon, growth rate is accompanied by, or requires, increased N use efficiency. The total range in tissue-diet isotopic spacing in N seen in the experimental population of 25 fish was 1, approximately 50% of the total trophic shift. Mean equilibrium tissue-diet isotopic spacing (±standard deviation) in salmon averaged 2.3 (±0.3) and 0.0 (±0.3) for N in muscle and liver, respectively, and 2.1 (±0.1) and 1.6 (±0.3) for C in muscle and liver, respectively. Feeding with a mixed dietary source (wheat and fish-meal origin) resulted in tissue-diet isotopic fractionation in both C and N due to the differential digestibility of food components with distinct isotopic composition. The rate of change in isotopic composition of S. salar tissues was dominated by growth, but the estimated contribution of metabolic turnover to change in tissue N was relatively high for an ectothermic animal at ca. 20-40%. The estimated half-life for metabolic turnover of the tissue N pool was ca. 4 months in both muscle and liver tissue. This is the first study to demonstrate a direct relationship between tissue-diet isotopic spacing in N and growth rate and adds to the growing list of factors known to influence the level of isotopic separation between a consumer's tissue and that of its diet
Identifying migrations in marine fishes through stable-isotope analysis
No full textThe isotopic composition of many elements varies across both land and ocean surfaces in a predictable fashion. These stable-isotope ratios are transferred into animal tissues, potentially providing a powerful natural geospatial tag. To date, most studies using stable isotopes as geolocators in marine settings have focussed on mammals and seabirds conducting large ocean-basin scale migrations. An increasing understanding of isotopic variation in the marine environment, and improved sampling and analytical techniques, however, means that stable isotopes now hold genuine promise as a natural geolocation tag in marine fishes. Here, the theoretical background underpinning the use of stable isotopes of C, N and O in otolith, scale and muscle tissues as geolocation tools in the marine environment is reviewed, and examples of their applications are provided
Rare earth element geochemistry and taphonomy of terrestrial vertebrate assemblages
No full textMost taphonomic analyses of vertebrate remains have focused upon physical processes. Chemical processes only rarely are addressed, leaving a large untapped store of quantitative taphonomic information contained within the bones themselves. In this paper, the rare earth element (REE) signature of fossil bones in terrestrial deposits is shown to be controlled by the early diagenetic environment. Thus, bones fossilized in different early diagenetic environments may be separated by their distinct REE signatures. Furthermore, the variation of REE patterns developed in individual bones within an assemblage is controlled by sedimentologic and taphonomic processes. Hence, the degree of mixing and reworking (relative time and space averaging) of vertebrate elements within a particular assemblage may be determined from the REE patterns of the interred bones. REE geochemistry represents a new and powerful taphonomic tool
A geochemical method to trace the taphonomic history of reworked bones in sedimentary settings
No full textRare earth element (REE) signatures can be used to identify the original mode of deposition of fossil bones and teeth that have been reworked. This new technique may resolve the notoriously difficult problem of assessing the amount of transport or reworking undergone by fossil bones and teeth on the basis of physical parameters, such as degree of abrasion. Different REE signals characterize different pore-water environments. Bones and teeth, composed of apatite, incorporate REEs rapidly during early diagenesis, and the REE signature in the bone is controlled by that of the surrounding pore waters. Reworked bones and teeth may show REE traces suggesting early-diagenetic pore-water conditions different from those indicated by in situ sedimentary or geochemical evidence. This situation is demonstrated in a case study from the Rhaetian (latest Triassic) of southwest England, where different bone beds are compared. In one case, the original environmental setting of reworked bone is traced by matching REE traces with contemporaneous unreworked bone assemblages in neighboring areas
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