Alabaster is great for building statues, artworks and monuments. That is a fact which did not change since medieval times. The question is, where the medieval and Renaissance sculptors in Europe got their alabaster from? W. Kloppmann et al. (2017) show that isotope fingerprints of the alabaster can link artworks to their source areas. The method benefits i.a. “from the strong variations of isotope ratios of S, O, Sr in seawater and the associated evaporites through the Mesozoic”. That means that, although optically there is no difference between different alabster peices, every alabaster quarry (“mine”) differs in its mixture of S, O and Sr isotopes. In order to test this new method for finding the origin of alabaster, W. Kloppmann et al. analyzed 66 alabster artworks from different museums and collections. They were able to show that besides the known alabaster quarries in the English Midlands and in northern Spain, there was also a long-lived but little-documented alabaster trade radiating from the French Alps.
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Copper… on the one hand copper is an important trace element for life (for example as part of the red blood cells), on the other hand it is toxic. Water-soluble copper in inshore waters and soil is a danger for many microorganisms and plants. Therefore, it is important to understand the dispersion of water-soluble copper. When you add water-soluble copper (Cu) into soil, it instantly partitions between solid and solution phases. However, this state is not stable: with increasing “age”, its lability (bioavailability, toxicity, isotopic exchange-ability and extractability) decreases because of diffusion and reactions with the surrounding material. Theoretical models help to predict this time dependent change in lability, which depends on a lot of soil parameters like temperature, soil organic matter content and soil pH. Zeng, et al. (2017) published an improved model for copper lability which describes short and long term effect of water-soluble copper added to soil in one single model. In their model, copper lability depends on three processes:
The model showed good predicting ability when compared to experimental data of different soil samples with different chemical properties (like pH value, clay and organic carbon content and copper concentration), although other copper ageing processes like moisture, plant absorption, and microbial activities are not considered. "A new model integrating short- and long-term aging of copper added to soils"
Zeng S, Li J, Wei D, Ma Y (2017) PLOS ONE 12(8): e0182944. Different magnetic materials can be found in the crust of the earth. However, just lodestones have the ability to behave like a magnet. The fact that lodestones were the base of the first compasses, is still hidden in their name “lode”(=course)-stone. In 1994, electron microscopy revealed the secret structure of lodestones. It was known before that lodestones are made of oxidized magnetide (Fe3O4), but not all oxidized magnetide was lodestone. The secret of lodestones lay on an intergrowth of magnetite (Fe3O4) and maghemite (Fe2O3). Nevertheless, this structure does not explain the origin of the charge. In 1999, Peter Wasilewski and Günther Kletetschka dealed with the question how lodestones gets charged. They calculated the magnetic field which would be needed to charge a lodestone and came up with an interesting hypothesis: Lodestones are charged up by lightning strikes. Experiments with “controlled” bolts showed that the magnetic field created by bolts can increase the remanent magnetization (= magnetization which remains) in lodestones. That would also explain why lodestones are found “near the surface and not in deep mines”. "Lodestone: Natures only permanent magnet ‐ What it is and how it gets charged."
Peter Wasilewski and Günther Kletetschka Geophysical research letters 26.15 (1999): 2275-2278. |
IdeaI love to increase my general science knowledge by reading papers from different fields of science. Here I share some of them. Archiv
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