scholarly journals CALCIUM OXALATE RADIOCARBON DATING: PRELIMINARY TESTS TO DATE ROCK ART OF THE DECORATED OPEN-AIR CAVES, ERONGO MOUNTAINS, NAMIBIA

Radiocarbon ◽  
2020 ◽  
pp. 1-12
Author(s):  
Jean-Pascal Dumoulin ◽  
Matthieu Lebon ◽  
Ingrid Caffy ◽  
Guilhem Mauran ◽  
Alma Nankela ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Calcium Oxalate ◽  
Organic Compounds ◽  
Radiocarbon Dating ◽  
Rock Art ◽  
Targeted Sampling ◽  
Heritage Site ◽  
Carbon Compounds ◽  
First Results ◽  
Two Phases

ABSTRACT The direct dating of rock paintings is not always possible due to the lack of organic carbon compounds in pigments, or because sampling from a heritage site is often restricted. To overcome these limitations, dating laboratories have to develop new approaches. In this study, we consider sampling calcium oxalate crusts covering the painted artworks as a way to indirectly date the rock art. This stratigraphic approach includes isolating and extracting pure oxalate from the crusts. The approach was tested on natural bulk accretions collected in the open-air sites of Erongo Mountains in Namibia. The accretions were separated into two phases (pure oxalate and the remaining residues) with a special pretreatment. This process removes carbonates through acidification (HCl 6N) and dissolves the oxalate into the supernatant, leaving the minerals and windblown organic compounds in the residue. The efficiency of the separation was checked on the two phases by FTIR analyses and by 14C dating and showed that pure oxalate powders were indeed obtained. AMS radiocarbon results of various accretions on the same art panels provided ages from modern periods to 2410 ± 35 BP. From these first results, more targeted sampling campaigns can be considered to provide a terminus ante quem for the rock art.

On human blood, rock art and calcium oxalate: further studies on organic carbon content and radiocarbon age of materials relating to Australian rock art

Antiquity ◽  
1997 ◽  
Vol 71 (272) ◽  
pp. 430-437 ◽  
Author(s):  
Richard Gillespie
Keyword(s):  
Organic Carbon ◽  
Calcium Oxalate ◽  
Human Blood ◽  
Ancient Dna ◽  
Rock Art ◽  
Field Studies ◽  
Organic Carbon Content ◽  
Radiocarbon Age ◽  
Archaeological Materials ◽  
Supplementary Report

Minute biological traces, with their prospect of recovering even ancient DNA, are the most attractive of archaeological materials to work with. This supplementary report on field studies of rock-art first published in ANTIQUITY further explores how these studies may in truth be carried out.

Radiocarbon Dating in Rock Art Research

2017 ◽  
Author(s):  
Fiona Petchey
Keyword(s):  
Organic Carbon ◽  
Radiocarbon Dating ◽  
Rock Art ◽  
Radiocarbon Date ◽  
Variable Composition ◽  
Radiocarbon Dates ◽  
Fully Integrated ◽  
Dating Method ◽  
Potential Impact ◽  
Art Research

Radiocarbon dating has had a significant impact on rock art research, but an initial enthusiasm for this dating method by archaeologists has been replaced by a degree of scepticism. Radiocarbon dates undertaken directly on rock art or on associated mineral crusts have often reinforced such scepticism, in part because organic carbon-based materials are present in small quantities and their composition is of such variable composition that the technique is stretched to its limits. For the researcher planning to obtain radiocarbon dates, it is essential to have an understanding of the dating options available, limitations of the technique, the potential impact of their own bias, and the value of a dating programme that is fully integrated within a larger project. This chapter outlines the various materials and methods used to radiocarbon date rock art. It includes some recent examples and highlights some advances as well as shortfalls in the dating of rock art.

Assimilation of various organic carbon sources by Haematococcus strains

2009 ◽  
Vol 57 (2) ◽  
pp. 231-237
Author(s):  
M. Zych ◽  
A. Stolarczyk ◽  
K. Maca ◽  
A. Banaś ◽  
K. Termińska-Pabis ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Present Experiment ◽  
Carbon Sources ◽  
Growth Conditions ◽  
Mixotrophic Growth ◽  
Naturally Occurring ◽  
Organic Carbon Sources ◽  
Secondary Carotenoids ◽  
Colour Changes

Differences in the assimilation of individual organic compounds (5 mM sugars and L-asparagine) under mixotrophic growth conditions were described for three naturally occurring Haematococcus strains.The effects of assimilation were measured by the growth intensity and size of algal cells, and the effect of colour changes in the cultures was observed. Some compounds caused the cell colouration to change from green to yellow, being the result of chlorophyll disappearance and the accumulation of yellow secondary carotenoids. In the present experiment none of the cultures turned red, thus excluding the intense accumulation of the commercially interesting carotenoid, astaxanthin.

scholarly journals Oxygen consumption during mineralization of organic compounds in water samples from a small sub-tropical reservoir (Brazil)

2003 ◽  
Vol 46 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Marcela Bianchessi da Cunha-Santino ◽  
Irineu Bianchini Júnior
Keyword(s):  
Oxygen Consumption ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Tannic Acid ◽  
Theoretical Calculations ◽  
Tropical Reservoir ◽  
First Order ◽  
First Order Kinetics ◽  
Mineralization Processes ◽  
Carbon Concentrations

Assays were carried out to evaluate the oxygen consumption resulting from mineralization of different organic compounds: glucose, sucrose, starch, tannic acid, lysine and glycine. The compounds were added to 1 l of water sample from Monjolinho Reservoir. Dissolved oxygen and dissolved organic carbon were monitored during 20 days and the results were fitted to first order kinetics model. During the 20 days of experiments, the oxygen consumption varied from 4.5 mg.l-1 (tannic acid) to 71.5 mg.l-1 (glucose). The highest deoxygenation rate (kD) was observed for mineralization of tannic acid (0.321 day-1) followed by glycine, starch, lysine, sucrose and glucose (0.1004, 0.0504, 0.0486, 0.0251 and 0.0158 day-1, respectively). From theoretical calculations and oxygen and carbon concentrations we obtained the stoichiometry of the mineralization processes. Stoichiometric values varied from 0.17 (tannic acid) to 2.55 (sucrose).

scholarly journals Fate of Trace Organic Compounds in Hyporheic Zone Sediments of Contrasting Organic Carbon Content and Impact on the Microbiome

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3518
Author(s):  
Cyrus Rutere ◽  
Malte Posselt ◽  
Marcus A. Horn
Keyword(s):  
Organic Carbon ◽  
Organic Compounds ◽  
Hyporheic Zone ◽  
Community Dynamics ◽  
Rrna Gene ◽  
Organic Carbon Content ◽  
Trace Organic Compounds ◽  
Sediment Samples ◽  
Removal Efficiencies ◽  
Trace Organic

The organic carbon in streambed sediments drives multiple biogeochemical reactions, including the attenuation of organic micropollutants. An attenuation assay using sediment microcosms differing in the initial total organic carbon (TOC) revealed higher microbiome and sorption associated removal efficiencies of trace organic compounds (TrOCs) in the high-TOC compared to the low-TOC sediments. Overall, the combined microbial and sorption associated removal efficiencies of the micropollutants were generally higher than by sorption alone for all compounds tested except propranolol whose removal efficiency was similar via both mechanisms. Quantitative real-time PCR and time-resolved 16S rRNA gene amplicon sequencing revealed that higher bacterial abundance and diversity in the high-TOC sediments correlated with higher microbial removal efficiencies of most TrOCs. The bacterial community in the high-TOC sediment samples remained relatively stable against the stressor effects of TrOC amendment compared to the low-TOC sediment community that was characterized by a decline in the relative abundance of most phyla except Proteobacteria. Bacterial genera that were significantly more abundant in amended relative to unamended sediment samples and thus associated with biodegradation of the TrOCs included Xanthobacter, Hyphomicrobium, Novosphingobium, Reyranella and Terrimonas. The collective results indicated that the TOC content influences the microbial community dynamics and associated biotransformation of TrOCs as well as the sorption potential of the hyporheic zone sediments.

scholarly journals ПЕРВЫЕ ДАННЫЕ ПО РАДИОУГЛЕРОДНОЙ ХРОНОЛОГИИ ПОСЕЛЕНИЯ КАМЕННЫЙ ЛОГ I (РЕСПУБЛИКА ХАКАСИЯ)

2020 ◽  
Author(s):  
A. Poliakov ◽  
◽  
P. Hommel ◽  
L. Marsadolov ◽  
V. Lurie ◽  
...  
Keyword(s):  
Bronze Age ◽  
Radiocarbon Dating ◽  
Late Bronze Age ◽  
Oxford University ◽  
First Results

This abstract presents the first results of Kamenniy Log I, the Late Bronze Age settlement at Minusinsk Hollow, radiocarbon dating. This investigation was based on samples from the different dwellings. The analysis, which had been made at the laboratories of the Oxford University, confirmed earlier assumptions about the sustainable chronology of this key site (XIV–X BC).

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