WEBDec 1, 2003 · The silicifiion of wood is a permineralization process by silica solution or colloid [66], [67]. Silica saturated waters can be supplied under the influence of volcanic activities or intense ...
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WEBDec 15, 2015 · Permineralised plant material is very scarce in the CantabrianAsturian fold belt, being restricted to a mention of coalballs from the upper Westphalian of Lieres in Asturias (Renier, 1926) and welldocumented coalball specimens at Truébano in the province of León, presumably of late Namurian age (Beckary, 1987a, Beckary, 1987b, .
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WEBHowever, the Donets Basin coal balls studied by Zodrow et al. (2002) have a different paragenetic sequence to the Williamson No. 3 coal balls. For example, the Donets coal balls were dolomitized after they formed, and the highMg calcite in these coal balls may have formed due to diagenetic alteration of lowMg calcite during dolomitization ...
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WEBJan 31, 2020 · As an example, a calamitalean showing wood made of nearly ... of coal balls and their narrow ecological and stratigraphic window of formation considerably limit their use for growth form reconstructions. The material from the Parnaíba Basin combines morphological and anatomical information obtained from large silicified stems and .
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WEBJan 1, 2000 · The concentrated coal‐ball areas were created by the triggered degassing of CO 2 from partially decomposed peat in the presence of ions from fresh waters; ¹³ C/ ¹² C ratios in these coal ...
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WEBPetrifactions and permineralizations are two types of preservation that provide exceptional resolution of (parts of) organisms that became immersed in water with high concentrations of dissolved minerals (, silica, calcium carbonate) (Plates 1–5 ). Once the mineral is precipitated and hardened, the organism is entombed in rock and often ...
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WEBArborescent marratialean ferns are the dominant elements with Pecopteris and Scolecopteris leaves being the most common; the calamiteans are the second in abundance. Generally the chert blocks contain a large number of plant fragments – roots and leaves are being almost equally represented – suggestive of a coal balllike plant .
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WEBSep 11, 2023 · The coal ball contains Stigmaria (Lepidodendrales), Sphenophyllum (Equisetales), Myeloxylon (Medullosales) and some gymnosperm wood. More recently, Césari et al . ( 2015 ) described wellpreserved silicified trunks of Cordaixylon as well as roots of Psaronius (Marattiales) from Stephanian C deposits in Asturias (Cantabrian .
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WEBJun 9, 2022 · Identifiion and Description[iv] Daldinia concentrica is a relatively easy to identify mushroom that resembles hard, roundish lumps of coal stuck to the surface of decaying deadwood. Furthermore, unlike most other mushrooms, D. concentrica does not possess a cap, gills, pores, or even a stem. Instead, this species has a fruitbody .
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WEBAug 1, 2017 · A silicified gymnospermous wood, Yangquanoxylon miscellum gen. nov. et sp. nov., is described from the Upper Pennsylvanianlower Permian Taiyuan Formation, Yangquan City, Shanxi Province, North China. The pycnoxylic wood is composed of thickwalled tracheids and thinwalled rays. It is characterized by mixed radial tracheid pits, .
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WEBJan 8, 2019 · They are commonly preserved through silicifiion, calcifiion, dolomitization, opalization, pyritization and sideritization, whereby silicified, calcified and dolomitized coal balls are best preserved (Zheng et al. 2008). Significantly, the number of fossil wood specimens in western Liaoning is very high, and most of them are silicified.
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WEBJun 5, 2019 · The examples are silicified wood, coalballs etc. The coalballs are of localised occurrence which are irregularly rounded concrete masses, commonly made up of calcite containing preserved fragments of coal forming plants. Each coalballs contains calcium carbonate, magnesium carbonate and sometimes iron sulphate. 2.
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WEBMay 1, 2007 · However, the fossil record of calamite plants is exceptionally rich and additionally diverse in terms of preservation. Besides the compressions there are threedimensionally preserved remains, such as plant parts preserved in coal balls or permineralised trunks, which give insights into anatomy and internal organisation of the .
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WEBAn extensive lithic workshop and raw material procurement site was discovered near West Rainy Butte, Slope County, North Dakota, in 1982 during the University of North Dakota archaeological field school. The site covers over 500,000 m2 on a small ridgetop approximately 2 km southwest of West Rainy Butte (Fig. 1). Pebble, cobble, and small .
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WEBApr 1, 2019 · Silicified wood with coniferous affinity provides a distinct point of view from impression fossils to detect the terrestrial ecosystem during this spectacular time interval (Feng et al., 2011;Wan ...
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WEBNov 20, 2017 · Petrified wood has traditionally been divided into two egories based on preservation processes: permineralization (where tissues are entombed within a mineralfilled matrix) and replacement (where organic anatomical features have been replied by inorganic materials). New analytical evidence suggests that for most petrified wood, .
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WEBMar 30, 2021 · The CL characteristics of quartz phases in silicified wood can mostly be related to blue (390 and 440 nm), yellow (580 nm), and red (650 nm) emission bands, which may appear in different ...
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WEBApr 1, 2019 · Wholeplant reconstructions of some cordaitalean plants from the Carboniferous and Permian coal balls supported the idea that this type of root has a cordaitalean affinity (Rothwell and Warner, 1984, Costanza, 1985, Trivett and Rothwell, 1985, Trivett and Rothwell, 1988, Taylor, 1988, Stewart and Rothwell, 1993, Wang et al., .
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WEBJan 1, 2008 · Silicifiion of wood was performed in the laboratory to improve the physical properties ( wear r esistance, water absorp. tion, hardness) of the material. Experimental studies were carried ...
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WEBMar 30, 2011 · Une étude des flores silicifiées du Permien basal de la Sardaigne et du Massif central, avec une correacute;lation biochronostratigraphique et des impliions paléogéographiques.
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WEBAug 29, 2019 · Sphenophyllum Brongniart, 1828 is the bestknown representative of Sphenophyllales, an extinct order of small plants belonging to the Sphenophytes, the group that contains extant horsetails.
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WEBAug 1, 1975 · Coal balls occur in the paralic coal basins (those of coastal swamps) of Carboniferous age in America and Europe. Strangely, the coalforming coastal swamps of Tertiary and ~retaceous age have never yielded coal balls of a similar type, although some equivalent but somewhat different types of permineralization occur (Gothan, 1937, .
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WEBMeasuring density of silicified wood and determining weight loss after 450 °C heating provides useful data for interpreting the process of permineralization. ... 119 2 of 17 plant tissues preserved in calcareous "coal balls", modern hot spring sinter, and some fossiliferous cherts, and in these specimens significant amounts of relict ...
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WEBIt almost always consists of common opal, without playofcolor, but rare instances of petrified wood composed of precious opal are known. Opalized Wood: A cabochon made from opalized wood from eastern Oregon. This cabochon measures approximately x 17 millimeters and weighs carats. GIA Lab Report for this stone.
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A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
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