Matthias Hüls

How Clean is Ultrafiltration Cleaning of Bone Collagen

As part of our bone dating development, we have tested the ultrafiltration of bone gelatin using 2 different filtersVivaspin 20 (VS20), a polyethersulfone, and Vivaspin 15R (VS15R), a cellulose, both with a 30,000 molecular weight cutoffand bone collagen from dated samples ranging in age from 1.5 to >50 kyr BP. A direct accelerator mass spectrometry (AMS) measurement yielded radiocarbon concentrations of ~0.5 pMC (~42 kyr) for the polyethersulfone, ~14.417.5 pMC (~15.614 kyr) for the cellulose, and ~107.4 pMC for the glycerin. The filters were cleaned before use similar to the Oxford protocol (Bronk Ramsey et al. 2004), and a series of freeze-dried archaeological bone gelatin samples and a modern pig-skin gelatin were passed through VS20 and VS15R filters (Vivascience). We recovered both the eluent ( 30 kD) in order to obtain a carbon mass and isotope balance. While the >30-kD collagen fraction that is usually selected for AMS analysis does not appear to be significantly contaminated, measurements show significant age differences between the eluent 30-kD fraction. Until a contamination with filter carbon of the >30-kD collagen fraction can be excluded, we would recommend caution in the use of ultrafiltration for cleaning bone collagen with VS20 or VS15R ultrafilters.

A sedimentary record of Holocene surface runoff events and earthquake activity from Lake Iseo (Southern Alps, Italy):

This study presents a record of Holocene surface runoff events and several large earthquakes, preserved in the sediments of pre-Alpine Lake Iseo, northern Italy. A combination of high-resolution seismic surveying, detailed sediment microfacies analysis, non-destructive core-scanning techniques and AMS 14C dating of terrestrial macrofossils was used to detect and date these events. Based on this approach, our data shed light on past seismic activity in the vicinity of Lake Iseo and the influence of climate variability and human impact on allochthonous detrital matter flux into the lake. The 19 m long investigated sediment sequence of faintly layered lake marl contains frequent centimetre- to decimetre-scale sandy-silty detrital layers. During the early to mid Holocene, these small-scale detrital layers, reflecting sediment supply by extreme surface runoff events, reveal a distinct centennial-scale recurrence pattern. This is in accordance with regional lake-level highstands and minima in solar activity and thus apparently mainly climate-controlled. After c. 4200 cal. yr BP, intervals of high detrital flux occasionally also correlate with periods of enhanced human settlement activity. In consequence, deposition of small-scale detrital layers during the late Holocene apparently reflects a rather complex interplay between climatic and anthropogenic influences on catchment erosion processes. Besides the small-scale detrital layers, five up to 2.40 m thick large-scale detrital event layers, composed of basal mass-wasting deposits overlain by large-scale turbidites, were identified, which are supposed to be triggered by strong earthquakes. The uppermost large-scale event layer can be correlated to a documented Mw=6.0 earthquake in ad 1222 in Brescia. The four other large-scale event layers are supposed to correspond to previously undocumented local earthquakes. These occurred around 350 bc, 570 bc, 2540 bc and 6210 bc and most probably also reached magnitudes in the order of Mw = 5.0–6.5.

Mussels with Meat: Bivalve Tissue-Shell Radiocarbon Age Differences and Archaeological Implications

Local reservoir ages are often estimated from the difference between the radiocarbon ages of aquatic material and associated terrestrial samples for which no reservoir effect is expected. Frequently, the selected aquatic material consists of bivalve shells that are typically well preserved in the archaeological record. For instance, large shell middens attest to the importance of mussel consumption at both coastal and inland sites. However, different physiological mechanisms associated with tissue and shell growth may result in differences in reservoir effects between the surviving component (shell) and the component relevant to dietary reservoir effects in consumers (tissue). The current study examines bivalve tissue-shell age differences both from freshwater and marine contexts close to archaeological sites where human consumption of mollusks has been attested. Results exhibited significant 14C age differences between bivalve tissue and shell in a freshwater context. In a marine context, no significant bivalve tissue-shell age differences were observed. The results also showed that riverine and lacustrine shells show large and variable freshwater reservoir effects. The results have important implications for establishing local reservoir effects especially in a freshwater environment. For good a priori knowledge of expected 14C differences in organic and inorganic water, carbon is thus necessary. Furthermore, the high variability in freshwater shell 14C ages implies the need for representative sampling from the archaeological record.

The Homo aurignaciensis hauseri from Combe-Capelle: a Mesolithic burial.

On August 26, 1909, a laborer, employed by Otto Hauser discovered a human skull at the site of Roc de Combe-Capelle in the department of the Dordogne (southwestern France). Hauser, who was absent from the site at the time, was immediately made aware of the important nature of the remains, which were discovered about 2 m below the surface (Hauser, 1924). In the subsequent weeks, he organized the excavation of the burial with the support of anthropologist Hermann Klaatsch. The find was rather welldocumented for that time and according to a series of photographs, the skeleton, estimated to be between 40 and 50 years of age, was lying in a flexed position, turned to the right, in a NeS direction (Fig. 1). Hauser and Klaatsch proposed that the burial was connected with the lowermost ‘Aurignacian’ layer. This was the only identified early Upper Paleolithic assemblage recognized at this time, as corroborated by a number of supposed grave goods and 16 mollusc shells, mostly perforated, which were found close to the skull (Klaatsch and Hauser, 1910). Otto Hauser was also a businessman and within a few weeks he made Combe-Capelle well-known as an early modern human burial site. Hauser offered to sell the find, together with the Neandertal specimen found in 1908 at Le Moustier (France), for 160,000 Goldmark. The Berlin Museum arranged to purchase the finds, with the support of donors such as Kaiser Wilhelm II, and both burials were on display in the German capital from 1910 onwards. On February 3, 1945, the postcranial remains of the skeletons were destroyed during the bombing of the MartinGropius building, while the skulls were safely deposited in the storage rooms (Hoffmann, 2003). In 1955, a few burnt human bones

A 14 000-year-old amber elk and the origins of northern European art

A Late Palaeolithic amber figurine has been skilfully recovered and reassembled from a ploughed open site in northern Germany. Dated between 11 800 and 11 680 cal BC it occupies a key point between the Magdalenian and the Mesolithic. The authors show that the figurine represents a female elk which was probably carried on the top of a wooden staff. They argue for continuity of art but change of belief in this crucial transition period.

Sampling Iron for Radiocarbon Dating: Influence of Modern Steel Tools on 14C Dating of Ancient Iron Artifacts

Before the 17th century, charcoal was regularly used in the production of iron (smelting and forging) and some of this charcoal carbon was incorporated into the iron. Depending on the age of the wood used to produce the charcoal, the age of the carbon incorporated in the iron lattice can reflect the age of manufacture of the iron artifacts. A reliable preparation method allowing for the routine dating of iron artifacts would permit the dating of numerous objects for which now the age can only be estimated. In an earlier work (Huls et al. 2004), we tested the extraction of carbon from iron samples by closed-tube combustion. The samples were cut in small pieces to ease the release of the carbon from the lattice. During the tests, it became clear that the steel tools used to cut the samples can add contamination at the surface. As modern steel is made using coal, this leads to erroneously old ages. We have tested ways to reduce or eliminate this surface contamination from the sampling tools using iron artifacts of known ages. In order to quantify the contamination, we produced standard test materials from pure iron (99.998% Fe) melted with carbon of known 14C content and prepared samples using different cutting tools. The results of these tests indicate that the proper choice of cutting technique and tool, combined with an additional cleaning of the freshly cut surface, reduces sample contaminations to low levels; measured sample 14C concentrations are close to the 14C content of the charcoal used to produce these standard iron samples.