Fossil folklore: Molluscs

Paul D Taylor (UK) The final article of this series on fossil folklore focuses on molluscs, excluding the ammonites, which were covered earlier (see Fossil folklore: ammonites in Deposits, Issue 46, pp. 20–23). Molluscs are second only to arthropods in the number of species living today and the resistant calcareous skeletons possessed by the majority of species accounts for their extremely rich fossil record. Most fossil molluscs belong to one of three major groups – bivalves (oysters, clams and so on), gastropods (snails and slugs) and cephalopods (ammonites, belemnites and so on). Added to these are a few minor groups, … Read More

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Roman quarries in Austria and Germany: A short sight-seeing tour

Dr Robert Sturm (Austria) This is the third of four articles on the quarries of the ancient world and later, and, in particular, the marble that was quarried there and the works of art made from it. The first is Mining in Ancient Greece and Rome and the second is Marble from the Isle of Paros – a tour of the ancient quarries. The ancient methods used An antique quarry is interesting because it is a place where raw material for buildings and sculptural works was extracted to specific sizes and shapes with the technical methods of that time. The … Read More

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Agate: A mineral that develops with age, water and moganite

Terry Moxon (UK) Agate is banded or variegated chalcedony and this distinctive appearance allows a ready identification from any source. Many agate thick sections from basic igneous hosts are reminiscent of a series of distorted onion-like rings with the initial bands closely replicating the shape of the supporting gas cavity. However, the banding is frequently distorted and this general pattern is known under various names, for example, fortification or wall lining. A second type is less common and demonstrates apparently gravity-controlled horizontal bands. Agate host rocks are varied but the most abundant agate sources are the gas cavities of basic … Read More

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Erzberg Mine in Austria: An iron ore reserve with a long tradition

Dr Robert Sturm (Austria) The Erzberg Mine is situated in the Austrian county of Styria. From a geological point of view, it belongs to the so-called greywacke zone, which represents a band of Palaeozoic metamorphosed sedimentary rocks intercalated between the Northern Limestone Alps and the Central Alps. The Erzberg Mine is the world’s largest deposit of the iron mineral siderite (FeCO3), which is mixed with ankerite (CaFe[CO3]2) and dolomite (CaMg[CO3]2). Due to this mixture of different mineral phases, the concentration of iron ranges from 22% to 40% and adopts an average value of 33%. The annual output amounts to about … Read More

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