Magnetite grain-size analysis and sourcing of Mediterranean obsidians

Zanella, Elena; Ferrara, E.; Bagnasco, L.; Ollà, A.; Lanza, Roberto; Beatrice, C.

doi:10.1016/j.jas.2011.12.030

Cited by 20 publications

(23 citation statements)

References 12 publications

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“…Some authors underlined the possibility to distinguish magnetite of different sizes from single domain to multidomain. 16,19,21,22,24 However, to date a comprehensive correlation of the magnetic properties with the microstructure and morphology of Monte Arci obsidian is still lacking, despite the evidence for the copresence of a glassy matrix together with iron-containing micro-or nanolites. Indeed, although obsidian is usually defined as a natural glass, it is known from the literature that crystalline inclusions and occlusions, 2−18,20−37 among which, iron-based minerals, are often present, also in the case of the Monte Arci obsidian.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Indeed, although obsidian is usually defined as a natural glass, it is known from the literature that crystalline inclusions and occlusions, 2−18,20−37 among which, iron-based minerals, are often present, also in the case of the Monte Arci obsidian. 20,24,27,28,31,34,35 Feldspars (KAlSi 3 O 8 − NaAlSi 3 O 8 − CaAl 2 Si 2 O 8 ), 2,7,9,11,18,20,21,31 pyroxenes (XY(Si,Al) 2 O 6 ), 6,7,9,18,31 biotite (K(Mg,Fe) 3 AlSi 3 O 10 (OH) 2 ), 6,20,31 hornblende ((Ca,Na) 2−3 (Mg,Fe,Al) 5 (Al,Si) 8 O 22 (OH,F) 2 ), 7,18,21 silica polymorphs (cristobalite, tridymite, quartz), 11,31,33 apatite (Ca 10 (PO 4 ) 6 (OH,F,Cl) 2 ), 18,31 zircon (ZrSiO 4 ), 18,33 titanomagn e t i t e / m a g n e t i t e o r r e l a t e d s p i n e l s ( F e 3 O 4 , F e 2 + ( F e 3 + , T i ) 2 O 4 ) , 3 , 5 − 7 , 1 2 , 1 8 , 1 9 , 2 1 − 3 1 , 3 3 h e m a t i t e (α-Fe 2 O 3 ), 21−23,25−28 ilmenite (FeTiO 3 ), 18,25,28,31 pyrrhotite (Fe (1-x) S (x = 0 to 0.2)), 18 pyrite (FeS 2 ), 31 metallic iron, 27 pseudobrookite (TiO 2 ), 28 olivine ((Mg 2+ ,Fe 2+ ) 2 SiO 4 ),…”

Section: ■ Introductionmentioning

confidence: 99%

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Much More Than a Glass: The Complex Magnetic and Microstructural Properties of Obsidian

et al. 2016

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Obsidian is a natural volcanic glass in which nanocrystalline and microcrystalline phases can coexist with the glassy one. In this paper, magnetic properties of Monte Arci obsidians are investigated by an experimental approach commonly applied to synthetic nanostructured materials and rarely to natural ones, and correlated with the mineralogical composition and microstructure. Among the different crystalline phases, the iron-containing components are found to be responsible for a great variety of magnetic behaviors, including paramagnetism, antiferromagnetism, ferromagnetism, and superparamagnetism. The combined use of powder X-ray diffraction (PXRD), 57 Fe Mossbauer spectroscopy, DC magnetometry, and transmission electron microscopy (TEM/HRTEM) provides new insights in the Monte Arci obsidian: (i) the presence of magnetite nanoparticles spread into the glassy matrix; (ii) the presence of an antiferromagnetic phase responsible for a discontinuity at about 45 K; (iii) exchange bias phenomena, for the first time revealed in obsidians, due to the coupling between the nanostructured ferrimagnetic phase and the antiferromagnetic one; (iv) Goldanskii-Karyagin effect (GKE) associated with biotite.

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Much More Than a Glass: The Complex Magnetic and Microstructural Properties of Obsidian

et al. 2016

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“…For instance, the two Melos obsidian sources were differentiated, but one of them overlapped with other Aegean sources. Subsequent research also noted overlapping sources and high intra-flow variability, limiting the utility of magnetic parameters for discerning obsidian sources (Urrutia-Fucugauchi, 1999;Vásquez et al, 2001;Zanella et al, 2012). For differentiating among obsidian-bearing flows, the reported intra-flow variability was detrimental.…”

Section: Principles Of Obsidian Magnetic Characterizationmentioning

confidence: 99%

Middle Palaeolithic toolstone procurement behaviors at Lusakert Cave 1, Hrazdan valley, Armenia

Frahm

Feinberg

Schmidt-Magee

et al. 2016

Journal of Human Evolution

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Strategies employed by Middle Palaeolithic hominins to acquire lithic raw materials often play key roles in assessing their movements through the landscape, relationships with neighboring groups, and cognitive abilities. It has been argued that a dependence on local resources is a widespread characteristic of the Middle Palaeolithic, but how such behaviors were manifested on the landscape remains unclear. Does an abundance of local toolstone reflect frequent encounters with different outcrops while foraging, or was a particular outcrop favored and preferentially quarried? This study examines such behaviors at a finer geospatial scale than is usually possible, allowing us to investigate hominin movements through the landscape surrounding Lusakert Cave 1 in Armenia. Using our newly developed approach to obsidian magnetic characterization, we test a series of hypotheses regarding the locations where hominins procured toolstone from a volcanic complex adjacent to the site. Our goal is to establish whether the cave's occupants procured local obsidian from preferred outcrops or quarries, secondary deposits of obsidian nodules along a river, or a variety of exposures as encountered while moving through the river valley or across the wider volcanic landscape during the course of foraging activities. As we demonstrate here, it is not the case that one particular outcrop or deposit attracted the cave occupants during the studied time intervals. Nor did they acquire obsidian at random across the landscape. Instead, our analyses support the hypothesis that these hominins collected obsidian from outcrops and exposures throughout the adjacent river valley, reflecting the spatial scale of their day-to-day foraging activities. The coincidence of such behaviors within the resource-rich river valley suggests efficient exploitation of a diverse biome during a time interval immediately preceding the Middle to Upper Palaeolithic "transition," the nature and timing of which has yet to be determined for the region.

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“…Different sedimentary conditions have specific sediment grain size parameters and their assembly characteristics (Sun et al 2002 ; Vandenberghe et al 2018 ). Therefore, grain size analysis is extensively applied in environmental studies and used to reveal the origin of sediments (Zanella et al 2012 ), identify sedimentary environment types (Halls 1967 ; Friedman 1979 ), reflect hydrodynamic conditions during deposition, and infer sediment diffusion, transport, and deposition processes (Ma et al 2014 ; Rosenberger et al 2016 ).…”

Section: Introductionmentioning

confidence: 99%

Effects of cascade reservoir systems on the longitudinal distribution of sediment characteristics: a case study of the Heihe River Basin

Wang

Juan-juan

et al. 2021

Environ Sci Pollut Res

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Spatial variations in grain size parameters can reflect river sediment transport patterns and depositional dynamics. Therefore, 22 surficial sediment samples taken from the Heihe River and its cascade reservoirs were analyzed to better understand the impact of cascade reservoir construction on sediment transport patterns in inland rivers in China. The results showed that the longitudinal distribution of sediment grain size in the Heihe River was significantly affected by the influence of the cascade reservoirs. The retention rate in the cascade reservoir of the Heihe River reached 79% (193.53 Mt/year), which caused most of the fine sand to accumulate in the reservoir, and the sediment fining degree reached approximately 50%. However, the water discharged from the dam caused serious erosion of the riverbed and coarsening of the sediment, and the coarsening degree was approximately 500%. The backwater zone of the reservoir was influenced by both backwater and released water, and the coarsening degree of sediment was approximately 101%. Sedimentary environmental analysis revealed that the characteristics of the sediment grain size in an upstream tributary of the Heihe River were more influenced by source material than by hydrodynamic conditions, while the grain size characteristics of the mainstream sediments were controlled mainly by hydrodynamic conditions. The characteristics of sediment transport in different reaches of the Heihe River were studied, and the results may provide references for the operation of cascade reservoirs and the sediment control of reservoirs.

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Magnetite grain-size analysis and sourcing of Mediterranean obsidians

Cited by 20 publications

References 12 publications

Much More Than a Glass: The Complex Magnetic and Microstructural Properties of Obsidian

Much More Than a Glass: The Complex Magnetic and Microstructural Properties of Obsidian

Middle Palaeolithic toolstone procurement behaviors at Lusakert Cave 1, Hrazdan valley, Armenia

Effects of cascade reservoir systems on the longitudinal distribution of sediment characteristics: a case study of the Heihe River Basin

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