scholarly journals Rock procurement and use during the Middle Neolithic: The macrolithic tools of Dambach-la-Ville (Alsace, France)

2020 ◽  
Vol 7 (3) ◽  
pp. 1-13
Author(s):  
Florent Jodry ◽  
Marion Delloul ◽  
Christophe Croutsch ◽  
Philippe Duringer ◽  
Gilles Fronteau
Keyword(s):  
Sedimentary Rocks ◽  
Lower Triassic ◽  
Metamorphic Rocks ◽  
Archaeological Excavation ◽  
Rock Types ◽  
Use Wear ◽  
Grinding Stones ◽  
Interdisciplinary Study ◽  
Upper Rhine ◽  
Arkosic Sandstone

A preventive archaeological excavation carried out in 2012 at Dambach-la-Ville (Bas-Rhin, France) uncovered a large Middle Neolithic settlement (Upper Rhine West Bischheim group) dating from the second half of the 5th millennium BCE. The site comprised a very large assemblage of well-dated macrolithic tools (more than 600). Grinding stones, including about roughouts, make up the bulk of the assemblage. Morphological analyses indicate that certain types of use-wear are linked directly to specific types of rock. The variety of rock types is unusual for this period. In fact, contrary to other assemblages from the same period mainly made up of Lower Triassic sandstone (Vosges sandstone; 43%), the tools fashioned on this settlement are mostly made from sedimentary rocks of the Permian and Lower Triassic (possible sources at 15 km), and more rarely from plutonic and metamorphic rocks (possible sources between 5 and 15 km). The use of rough textured rocks such as arkosic sandstone or microconglomerate largely dominating the assemblage. This one also includes a large group of hammerstones from different rock types (sedimentary, plutonic, volcanic and metamorphic). More than half are silicified micritic limestones, a rock that is extremely rare and can be unambiguously traced to a single outcrop about 15 kilometres from the site. This systematic interdisciplinary study of the tools and their petrography offers the opportunity to explore questions regarding provenance and procurement networks in Alsace around 4150 BCE.

scholarly journals Rock Types Classification and Distribution on Anabanua Village, Barru Regency, South Sulawesi

2020 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Muhammad Resky Ariansyah ◽  
Muhammad Fawzy Ismullah Massinai ◽  
Muhammad Altin Massinai
Keyword(s):  
Sedimentary Rocks ◽  
Research Area ◽  
Igneous Rocks ◽  
The Other ◽  
Metamorphic Rocks ◽  
Geological Process ◽  
Rock Types ◽  
South Sulawesi ◽  
Geological Conditions ◽  
Limestone Sand

Anabanua Village, Barru Regency is one of the areas in South Sulawesi that has quite unique geological conditions. This condition inseparably comes from the complicated geological process that took place during the formation of the island, Sulawesi. In Anabanua Village, there are many types of rocks such as sedimentary rocks, metamorphic rocks and igneous rocks. This paper aims to map and classify the types of rock by taking samples on different places in the research area. Then we observe the samples physical properties. The results showed, from taking 10 rock samples in different places, they have various characteristics. 8 of them were sedimentary rocks, they are Limestone Quartz, Limestone Sand, Shale, Sandstone, Coal, Limestone Bioturbation, Breccia, and Chert Stone. The other 2 samples were metamorphic rocks, they are Greenschist and Quartzite.

Pyrite-pyrrhotine redox reactions in nature

1986 ◽  
Vol 50 (356) ◽  
pp. 223-229 ◽  
Author(s):  
A. J. Hall
Keyword(s):  
Redox Reactions ◽  
Sedimentary Rocks ◽  
Depositional Environments ◽  
Hydrothermal Solutions ◽  
Geochemical Processes ◽  
Iron Sulphide ◽  
Progressive Reduction ◽  
Rock Types ◽  
Iron Sulphides ◽  
The Common

AbstractThe origin in rocks of the common iron sulphides, pyrrhotine, Fe1-xS and pyrite, FeS2and their behaviour during geochemical processes is best considered using the simplified redox reaction: 2FeS ⇌ FeS2+ Fe2++ 2e−.Thus pyrrhotine is more reduced than pyrite and is the stable iron sulphide formed from magmas except where relatively high oxygen fugacities result from falling pressure or hydrothermal alteration. Pyrite, on the other hand, is the stable iron sulphide in even the most reduced sedimentary rocks where it usually forms during diagenesis through bacteriogenic reduction of sulphate; it is stable throughout the pressure/temperature range endured by normal sedimentary rocks. Pyrrhotine after pyrite or sulphate in metasediments of regional metamorphic origin results mainly from progressive reduction on metamorphism due to the presence of graphite-buffered fluids. Pyrrhotine and/or pyrite may be precipitated from hydrothermal solutions on epigenetic or syngenetic mineralization but pyrrhotine will only be preserved if protected from oxidation to pyrite or to more oxidized species. Exhalative pyrrhotine appears to have been more common in Precambrian times and/or in depositional environments destined to become regionally metamorphosed. FeS can be considered to be the soluble iron sulphide, rather than FeS2, in reduced aqueous systems although pyrite may precipitate from solution as a result of redox reactions. The relatively soluble nature of FeS explains the observed mobility of iron sulphides in all rock types.

scholarly journals Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Pauline Harlé ◽  
Alexandra R. L. Kushnir ◽  
Coralie Aichholzer ◽  
Michael J. Heap ◽  
Régis Hehn ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Ambient Temperature ◽  
Sedimentary Rocks ◽  
Flow Density ◽  
Upper Rhine Graben ◽  
Heat Flow Density ◽  
Density Estimates ◽  
Wet Rocks ◽  
Upper Rhine

AbstractThe Upper Rhine Graben (URG) has been extensively studied for geothermal exploitation over the past decades. Yet, the thermal conductivity of the sedimentary cover is still poorly constrained, limiting our ability to provide robust heat flow density estimates. To improve our understanding of heat flow density in the URG, we present a new large thermal conductivity database for sedimentary rocks collected at outcrops in the area including measurements on (1) dry rocks at ambient temperature (dry); (2) dry rocks at high temperature (hot) and (3) water-saturated rocks at ambient temperature (wet). These measurements, covering the various lithologies composing the sedimentary sequence, are associated with equilibrium-temperature profiles measured in the Soultz-sous-Forêts wells and in the GRT-1 borehole (Rittershoffen) (all in France). Heat flow density values considering the various experimental thermal conductivity conditions were obtained for different depth intervals in the wells along with average values for the whole boreholes. The results agree with the previous heat flow density estimates based on dry rocks but more importantly highlight that accounting for the effect of temperature and water saturation of the formations is crucial to providing accurate heat flow density estimates in a sedimentary basin. For Soultz-sous-Forêts, we calculate average conductive heat flow density to be 127 mW/m2 when considering hot rocks and 184 mW/m2 for wet rocks. Heat flow density in the GRT-1 well is estimated at 109 and 164 mW/m2 for hot and wet rocks, respectively. Results from the Rittershoffen well suggest that heat flow density is nearly constant with depth, contrary to the observations for the Soultz-sous-Forêts site. Our results show a positive heat flow density anomaly in the Jurassic formations, which could be explained by a combined effect of a higher radiogenic heat production in the Jurassic sediments and thermal disturbance caused by the presence of the major faults close to the Soultz-sous-Forêts geothermal site. Although additional data are required to improve these estimates and our understanding of the thermal processes, we consider the heat flow densities estimated herein as the most reliable currently available for the URG.

DENSITIES OF METAMORPHIC ROCKS

Geophysics ◽  
1971 ◽  
Vol 36 (4) ◽  
pp. 690-694 ◽  
Author(s):  
Scott B. Smithson
Keyword(s):  
Metamorphic Rock ◽  
Granite Gneiss ◽  
Biotite Granite ◽  
Metamorphic Rocks ◽  
Upper Crust ◽  
Rock Density ◽  
Rock Types ◽  
Crystalline Crust ◽  
The Mean ◽  
Few Data

Although metamorphic rocks comprise a large part of the crystalline crust, relatively few data concerning metamorphic rock densities are available. In this paper, we present rock densities from seven different metamorphic terrains. Mean densities for rock types range from [Formula: see text] for biotite granite gneiss to [Formula: see text] for diopside granofels. Mean rock densities for metamorphic terrains range from 2.70 to [Formula: see text]. Rock density may decrease in the lower part of the upper crust. Most mean rock densities for metamorphic terrains fall between 2.70 and [Formula: see text]; the mean density of [Formula: see text] commonly used for the upper crystalline crust is too low.

A Discussion on natural strain and geological structure - The control of ductility on the deformation of pebbles and conglomerates

1976 ◽  
Vol 283 (1312) ◽  
pp. 109-128 ◽  
Keyword(s):  
Confining Pressure ◽  
Geological Structure ◽  
Metamorphic Rocks ◽  
Tectonic Deformation ◽  
Low Grade ◽  
Rock Types ◽  
Gravitational Loading ◽  
The Matrix ◽  
Host Rocks

Pebbles are commonly used parameters for the determination of finite strain in deformed rocks. In high grade metamorphic environments, rocks probably behave as viscous fluids and a theory exists which relates the deformation experienced by a pebble to that of the host rocks. However, some deformed conglomerates are found in low grade metamorphic rocks where the assumption of viscous behaviour is unrealistic The deformation of artificial conglomerates made of geological materials, at room temperature and varying confining pressure is described. In these experiments, pebbles deform by cataclasis at surprisingly low applied loads and large finite strains are achieved. The amount of deformation experienced by pebbles of different rock types depends mainly on their yield strengths and ductility contrasts with respect to the matrix. A theoretical analysis assuming that pebble and matrix behave as workhardening Bingham materials during deformation relates the strain experienced by a pebble to that of the host rock. The results suggest that significant pebble deformation can occur during gravitational loading of sediments. An attempt is made to verify this idea by analysing the shape of pebbles in conglomerates of the Upper Witwatersrand System. At some sites the pebbles appear to have deformed during gravitational compaction while at others a tectonic deformation has been superimposed upon the pre-tectomic strain.

Evaluating the paleoclimatic significance of clay mineral records from a late Pleistocene loess-paleosol section of the Ili Basin, Central Asia

2017 ◽  
Vol 89 (3) ◽  
pp. 660-673 ◽  
Author(s):  
Yue Li ◽  
Yougui Song ◽  
Mengxiu Zeng ◽  
Weiwei Lin ◽  
Rustam Orozbaev ◽  
...  
Keyword(s):  
Central Asia ◽  
Clay Mineral ◽  
Late Pleistocene ◽  
Sedimentary Rocks ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Metamorphic Rocks ◽  
Paleoclimatic Reconstruction ◽  
Paleoclimatic Significance ◽  
Wind Intensity

AbstractIn this study, we present clay mineral records from a late Pleistocene loess-paleosol sequence in the Ili Basin, Central Asia, and assess their significance for paleoclimatic reconstruction. The results show that the clay minerals are mainly illite (average 60%) and chlorite (28%), with minor kaolinite (9%) and smectite (3%). Illite was of detrital origin with no obvious modification to its crystal structure. Increases in illite content in the loess are ascribed to wind intensity rather than pedogenesis. High proportions of illite in the clay fraction, and of muscovite in the bulk samples of the paleosol units, may lead to an overestimation of the weathering intensity. Kaolinite was likely inherited from the sedimentary rocks, while chlorite might have been inherited from both sedimentary and metamorphic rocks. The paleoclimatic signals of kaolinite and chlorite were unclear, due to reworking by both fluvial and eolian systems. Smectite was more likely formed by the transformation of biotite and illite, and its variation in the loess sequence was also controlled by wind intensity; this was largely due to aggregation and is unlikely to reflect moisture changes. Although the interpretation of paleoclimate evolution may contain some uncertainties, clay mineralogy does provide the possibility of tracing dust provenance.

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