scholarly journals Thermal characterisation of Bronze Age hearths from the cave of Les Fraux (Dordogne, France) by thermoluminescence and magnetic susceptibility techniques

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Aurélie Brodard ◽  
Pierre Guibert ◽  
François Lévêque ◽  
Vivien Mathé ◽  
Albane Burens ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Bronze Age ◽  
Iron Oxides ◽  
Fire Intensity ◽  
Equivalent Temperature ◽  
Sediment Characteristics ◽  
Sediment Samples ◽  
Quartz Grains ◽  
Reference Samples ◽  
Cave Sediment

In the cave of Les Fraux (Dordogne, France) numerous traces of fires are visible in the galleries. A multidisciplinary investigation was carried out to study these fires. This paper presents the methodology applied for the hearth study. It is based on the examination of the thermoluminescence (TL) of quartz and the magnetic susceptibility of iron oxides. First of all, magnetic susceptibility was measured on the surface of hearths. Based on both susceptibility mapping and visible sediment characteristics, small sediment samples (1-2 g) were taken. Subsequently, quartz grains were extracted from the sediment samples. Fourteen thermal references were obtained by heating (from 200 to 650°C) fractions of the pristine unfired cave sediment. Comparing the TL signal of anciently heated quartz to the reference samples allowed to obtain the maximum equivalent temperature attained for each sample extracted from ancient fires. Consequently, the correspondence between magnetic susceptibility and temperature allowed for the reconstruction of a paleotemperature map of the study area. This research provides information about fire intensity in the cave, which can help to understand its function.

Using polycyclic aromatic hydrocarbons to determine post-wildfire contamination and sediment sources in a large watershed in central British Columbia, Canada

2021 ◽  
Author(s):  
Kristen Kieta ◽  
Philip Owens ◽  
Ellen Petticrew
Keyword(s):  
British Columbia ◽  
Magnetic Susceptibility ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Sediment Samples ◽  
Burned Areas ◽  
Total Pahs ◽  
Polycyclic Aromatic ◽  
The Impact

<p>The Nechako River Basin (NRB) in central British Columbia is a large (52,000 km<sup>2</sup>), regulated basin that supports populations of sockeye and chinook salmon and the endangered Nechako white sturgeon. These important species are experiencing population declines and one potential cause of this decline is excess sediment, which can clog their spawning habitat and reduce juvenile success. This excess sediment is likely the product of a combination of factors, the most visible being the significant land cover changes that have occurred in the basin, which includes pressure from forestry and agriculture, the Mountain Pine Beetle epidemic, and large-scale wildfires in 2018. Focusing specifically on the impact of the 2018 wildfires on sediment transport from upland burned areas to adjacent waterways, this research aimed to determine the spatial and temporal contamination of tributaries and the mainstem of the Nechako River with polycyclic aromatic hydrocarbons (PAHs), which are produced during the combustion of organic matter and have been identified as toxic to aquatic organisms and to humans. Additionally, this study intended to determine if burned areas were a more significant contributor of sediment than unburned areas and better understand the utility of PAHs as a potential tracer. Source soil samples were collected in 2018 and 2020 from burned and unburned sites, and suspended sediment samples were collected throughout the ice-free period from 2018-2020 in three tributaries and three mainstem sites. All samples were analysed for PAHs, magnetic susceptibility, colour, and particle size. Results from the fall 2018 source samples show a significant difference in PAH concentrations between unburned and burned soils, and while concentrations of PAHs in source soils in 2020 were lower than in 2018, they were still elevated compared to unburned soils. Sediment samples showed that concentrations of total PAHs are higher in the mainstem sites than in the tributaries, with the greatest concentrations consistently found at the most downstream site on the mainstem of the Nechako River. Concentrations across sites were highest in samples taken during the spring snowmelt period in 2019, have decreased throughout the rest of the sampling period (2019-2020), and are well below sediment quality guidelines for total PAHs. In addition to determining the spatial and temporal extent of PAH contamination, this study also aims to use PAHs along with colour and measurements of magnetic susceptibility to trace sediments associated with the 2018 wildfires. The high cost of PAH analysis limits the number of samples that can be analysed and thus, these additional tracers will allow for the use of models such as MixSIAR that improve with a more robust number of samples. As large-scale megafires continue to burn across the globe, understanding their potential to contribute PAHs to local waterbodies and potentially be used as a tracer is as prescient as ever.</p>

scholarly journals Geochemistry of Fluvial Sediments from Geregu, Southwest Nigeria

2017 ◽  
Vol 64 (1) ◽  
pp. 35-52 ◽  
Author(s):  
Emmanuel E. Adiotomre ◽  
Innocent O. Ejeh ◽  
Edwin O. Adaikpoh
Keyword(s):  
Inductively Coupled Plasma ◽  
Tectonic Setting ◽  
Passive Margin ◽  
Fluvial Sediments ◽  
Geochemical Analysis ◽  
Sediment Samples ◽  
Inductively Coupled ◽  
Southwest Nigeria ◽  
Plasma Mass Spectrometry ◽  
Quartz Grains

Abstract Geochemical analysis of fluvial sediments on the banks of River Ero using inductively coupled plasma mass spectrometry illustrates their maturity, provenance and tectonic setting. The analysed sediment samples show low SiO2/Al2O3 ratios of 2.92-2.99 (units FL_A, FL_B and FL_E) and high SiO2/Al2O3 ratios of 4.064-4.852 (units FL_C, FL_D, FL_F and FL_G). Sediments were geochemically classified as shales (units FL_A, FL_B and FL_E) and greywackes (units FL_C, FL_D, FL_F and FL_G). Variability in sediment maturity (FL_F > FL_G >FL_C >FL_D >FL_A > FL_B > FL_E) parallels a decreasing order in the ratios of SiO2/Al2O3 and K2O/Al2O3, as well as the proportion of quartz grains and matrix components. Evidence from Al2O3/TiO2, K2O, Rb, La/Co, Th/Co, Cr/ Th, Th/Cr, La/Th-Hf, Th-Hf-Co and rare earth element contents of sediment samples suggest felsic protoliths of upper continental crust in a passive margin tectonic setting. An insignificant contribution of mafic components from the source is, however, inferred based on the Ni and Cr contents of the sediment samples. Combined Eu anomalies <0.85 and (Gd/Yb)n ratios <2.0 (1.53- 1.82, average 1.65) suggest post-Archean protoliths.

scholarly journals Morphological Analysis of Quartz Grains of Two Horizons in a Ultisol, Paraná – Brazil (Análise morfológica de grãos de quartzo de dois horizontes de Argissolos, Paraná – Brasil)

2017 ◽  
Vol 10 (4) ◽  
pp. 1059
Author(s):  
Fabiana Cristina Meira Zaparoli ◽  
Nelson Vicente Lovatto Gasparetto
Keyword(s):  
Iron Oxide ◽  
Surface Morphology ◽  
Iron Oxides ◽  
Morphological Analysis ◽  
Chemical Change ◽  
Subtropical Climate ◽  
Plasma Infusion ◽  
The City ◽  
Quartz Grains ◽  
Bt Horizon

This research aimed to compare the surface morphology of quartz grains of the E and Bt horizons of an Ultisol of the Aratu stream basin, in the city of Floraí, Paraná. The Ultisol is derived from sandstones of the Caiuá Formation and it is subjected to mesothermal humid subtropical climate. The materials from the E horizon showed abundant porosity compared to the Bt horizon ones, due to the filling of pores by coating of clay and iron oxides. On the surface of the quartz grains of the E horizon, several features were identified such as ";craters";, pyramidal microfeatures, gulfs of dissolution, elongated cavities, and silica reprecipitation, resulting from the chemical change, and fragmented grains resulting from a phenomenon called ";plasma infusion."; In the Bt horizon, nearly all the detrital grains were surrounded by clay and iron oxide. The detrital grains of the Bt horizon were better preserved, showing little corrosion features and rare fragmented grains, compared to the E horizon. These analyzes showed that the water flow accounts for the superficial alteration of detrital quartz grains when they are under the influence of humid subtropical climate.  R E S U M OA pesquisa teve como objetivo comparar a morfologia superficial de grãos de quartzo dos horizontes E e Bt de um Argissolo da bacia do córrego Aratu, no município de Floraí, PR. O Argissolo é derivado de arenitos da Formação Caiuá e submetido a clima subtropical úmido mesotérmico. Os materiais do horizonte E apresentam porosidade abundante quando comparados com os do horizonte Bt, em razão do preenchimento dos poros por revestimentos de argila e óxidos de ferro. Foram identificadas na superfície dos grãos de quartzo do horizonte E várias feições tipo “crateras”, microfeições piramidais, golfos de dissolução, cavidades alongadas, reprecipitação de sílica, oriundas da alteração química, e grãos fragmentados devido ao fenômeno denominado “plasma infusion”. No horizonte Bt, praticamente todos os grãos detritais estão envolvidos por argila e óxidos de ferro. Os grãos detritais do horizonte Bt estão mais preservados, exibindo poucas feições de corrosão e raros grãos fragmentados, se comparados com os do horizonte E. Essas análises demonstraram que o fluxo hídrico é o responsável pela alteração superficial dos grãos detritais de quartzo quando sob a influência de clima subtropical úmido. Palavras-chave: Argissolo, morfologia de grãos de quartzo, alteração geoquímica, fluxo hídrico 

Linking cave sediments and soil magnetism in the Urșilor cave (Romania)

2021 ◽  
Author(s):  
Cristian George Panaiotu ◽  
Cristian Necula ◽  
Relu D. Roban ◽  
Alexandru Petculescu ◽  
Ionut-Cornel Mirea ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Frequency Dependence ◽  
Remanent Magnetization ◽  
Rock Magnetism ◽  
Magnetic Mineral ◽  
Magnetic Data ◽  
Sediment Samples ◽  
Superparamagnetic Particles ◽  
Susceptibility Data ◽  
Cave Sediments

&lt;p&gt;Cyclical changes in the magnetic mineral assemblages have been observed in numerous sedimentary records confirming the relationship between rock magnetism and past global change. Several studies have shown that the magnetic susceptibility data of cave sediments reflect both long- and short-term climatic oscillations. These magnetic susceptibility variations are attributed to changes in climate-controlled pedogenesis which influence the production of low coercivity magnetic mineral phases, magnetite, and maghemite outside the cave. These soils with climate-dependent magnetic properties are then washed, blown, or tracked into the cave where they accumulate, creating the changes observed in rock magnetic data. We present a rockmagnetism study of the sediments from the Ur&amp;#537;ilor cave and the soils above the cave. Our focus is the detailed characterization of the ferromagnetic mineralogy preserved in the cave sediments and its links with potential soil sources. In the cave, we sampled four sections (2-3 m high) consisting mainly of silts and clays, with some sand layers. The age of the sediments is older than 40 ka. At the surface, we sampled various types of soils from 9 sites. For all samples, we measured: variation of magnetic susceptibility with frequency (976 and 15616 Hz), the anisotropy of magnetic susceptibility, isothermal remanent magnetization, and anhysteretic remanent magnetization. Because soils are characterized by the presence of superparamagnetic magnetite produced by pedogenesis which can be detected by the frequency dependence of magnetic susceptibility, we also measured the frequency dependence of soils and selected cave sediment samples at 13 frequencies (between 128 and 512000 Hz). Multi-frequencies measurements of the magnetic susceptibility of recent soils show that all the sampled soils have a strong frequency dependence indicating the presence of superparamagnetic particles produced by pedogenesis. Most of the sediment samples have an important frequency dependence similar to the one observed in the recent soils. As a preliminary conclusion, we can state that most of the fine cave sediments contain superparamagnetic particles, which can be probably attributed to soils transported into the cave by erosion. These results suggest that during the deposition of high magnetic susceptibility sediments it was a climate favorable for intense pedogenesis. The interpretation of the intervals with lower values of magnetic susceptibility is still under investigation to decide if represents a climatic signal or a change in the dynamics of sediment transport. &lt;strong&gt;Acknowledgment:&lt;/strong&gt; The research leading to these results has received funding from the EEA Grants 2014-2021, under Project contract no. EEA-RO-NO-2018-0126.&lt;/p&gt;

scholarly journals Bottom Sediment Characteristics of a Tropical Lake: Lake Tana, Ethiopia

Hydrology ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 18
Author(s):  
Mebrahtom G. Kebedew ◽  
Seifu A. Tilahun ◽  
Fasikaw A. Zimale ◽  
Tammo S. Steenhuis
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Bottom Sediment ◽  
Total Nitrogen ◽  
Available Phosphorus ◽  
Northwestern Part ◽  
Sediment Characteristics ◽  
Lake Tana ◽  
Sediment Samples ◽  
Water Hyacinths

Sediment concentration of rivers in developing countries has been increasing greatly over the last 50 years due to the conversion of forest to continuously cultivated land with the increasing population. Few studies have addressed its effect on sedimentation and water quality of the lakes by analyzing bottom sediment characteristics. In this study, the objective was to investigate the spatial distribution (and their interrelationships) of the bottom sediment characteristics in the largest lake in Ethiopia, Lake Tana where water hyacinths have been spreading rapidly during the last decade. Sediment samples were collected from the lake bottom at 60 locations and analyzed for texture, organic matter, total nitrogen, and available phosphorus. Bottom sediment samples had a median of 75% clay, 13% silt, and 9% sand. Clay was greatest in the northwestern part and smallest in the areas near the major rivers entering or exiting the lake. Clay percentage and lake depth were strongly correlated. The mean organic matter content of bottom sediment was 16 g kg−1, total nitrogen 0.8 g kg−1, and Olsen available phosphorus 19 mg kg−1. Phosphorus concentrations peaked where water hyacinths were found in the northeastern part of the lake. This study will serve as a baseline for future water quality and sedimentation changes in Lake Tana. In particular, it might aid in explaining the spread of the water hyacinths.

scholarly journals Predicting potentially toxic elements in tropical soils from iron oxides, magnetic susceptibility and diffuse reflectance spectra

CATENA ◽  
2018 ◽  
Vol 165 ◽  
pp. 503-515 ◽  
Author(s):  
Livia Arantes Camargo ◽  
José Marques ◽  
Vidal Barrón ◽  
Luís Reynaldo Ferracciú Alleoni ◽  
Gener Tadeu Pereira ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Iron Oxides ◽  
Toxic Elements ◽  
Diffuse Reflectance ◽  
Tropical Soils ◽  
Potentially Toxic Elements ◽  
Reflectance Spectra ◽  
Diffuse Reflectance Spectra

scholarly journals Chronology of construction and occupational phases of Nawamis tombs, Sinai based on OSL dating

2016 ◽  
Vol 43 (1) ◽  
pp. 121-130
Author(s):  
Ioannis Liritzis ◽  
Nikolaos Zacharias ◽  
Fahad Al-Otaibi ◽  
Ioannis Iliopoulos ◽  
Christos Katagas ◽  
...  
Keyword(s):  
Bronze Age ◽  
Time Span ◽  
Osl Dating ◽  
Late Bronze Age ◽  
Nomadic People ◽  
Circular Structures ◽  
Quartz Grains ◽  
Accumulated Dose ◽  
Age Estimates

Abstract The Nawamis are sandstone-built circular structures, located at several sites across Southern Sinai, Egypt. They are thought to be family tombs, created by the nomadic people that inhabited the area. Archaeological age estimates fall within the Early to Late Bronze Age. Here an interesting suite of nine OSL dates of three stone pieces has been resulted, from two Nawamis at Gebel Gunna and Ain Khodra fields. Single aliquot regeneration OSL of quartz grains provided the accumulated dose. XRD was used to identify mineralogy of several tombs. Based on the estimated luminescence ages a time span from Early and late Bronze ages is obtained, while some possible later activity, due to partial (re)construction or reuse of tombs, was detected.

scholarly journals Caracterização do Sedimentos de Fundo e Dinâmica Sedimentar da Enseada de Jurujuba (Baía de Guanabara), Niterói, RJ.

1996 ◽  
Vol 23 (1-2) ◽  
pp. 7 ◽  
Author(s):  
JOSÉ ANTONIO BAPTISTA NETO ◽  
MARIA AUGUSTA MARTINS DA SILVA
Keyword(s):  
Grain Size ◽  
Bottom Surface ◽  
Sediment Characteristics ◽  
High Wave ◽  
Sediment Samples ◽  
Sedimentary Characteristics ◽  
Distribution Shape ◽  
Sedimentary Dynamics ◽  
Bottom Surface Sediment ◽  
Current Energy

Sixty-four bottom surface sediment samples were collected in Jurujuba Bight using a Dietz LaFond grab sampler. They were analysed for grain size distribution, shape, mineralogy and geochemistry. From the association between the Bight bottom morphology and sediment characteristics, it was possible to establish the sedimentary dynamics. This allowed a division of the Bight into three sedimentary zones: an outer, sand-dominated zone of relatively high wave and current energy, an inner zone characterized by very calm conditions and clay/mud deposition and an intermediary zone of mixed sedimentary characteristics.

Revision of the Age of Construction Phases of a Mound Dated to the Late Copper–Early Bronze Age in Eastern Hungary Relying on14C-Based Chronologies

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1403-1412
Author(s):  
Gábor Szilágyi ◽  
Pál Sümegi ◽  
Sándor Gulyás ◽  
Dávid Molnár
Keyword(s):  
Magnetic Susceptibility ◽  
Bronze Age ◽  
The Body ◽  
Early Bronze Age ◽  
Burial Mound ◽  
The Absolute ◽  
Geochemical Analyses

ABSTRACTEcse Mound is a burial mound in the Hortobágy region of eastern Hungary. Built by prehistoric nomadic peoples from the east, it now stands on the border between two modern settlements. The construction of the mound was assumed to be related to representatives of the Pit Grave Culture populating the area between the Late Copper and Bronze Ages. This theory considered similarities in shape, orientation, and stratigraphy of this mound with other absolute-dated ones in the Hortobágy region alone. The mound comprises two construction layers as indicated by magnetic susceptibility and on-site stratigraphic observations. According to detailed sedimentological, geochemical analyses of samples taken from the bedrock, artificial stratigraphic horizons, and the overlying topsoil, there is a marked similarity between the soil forming the body of the mound in both artificial horizons and the underlying bedrock soil. In contrast the pedological, geological character of the modern topsoil is utterly different. According to our dating results, the uppermost stratigraphic horizon is coeval with the absolute-dated mounds in the region, assigning it to the period of the Pit Grave Culture. However, the lower anthropological horizon is older and dates to between the Early and Late Copper Ages.

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