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  • Patterns in Palaeontology: Exceptional Preservation of

    Article" Patterns in Palaeontology: Exceptional Preservation of Fossils in Concretions" by Victoria E McCoy published on PALAEONTOLOGY[online] with in the Patterns in Palaeontology category, by Victoria McCoy*1 Introduction: Have you ever seen a geode — a boring-looking ball-shaped rock that, when split open, reveals a remarkable crystalline.

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  • Woodbury Formation (NJKwb;1)

    Unit conspicuously micaceous throughout and contains finely dispersed pyrite, carbonaceous matter, and small pieces of carbonized wood as much as 30 cm (12 in) in length Small siderite concretions are abundant in the Woodbury in the northern part of the outcrop belt.

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  • Wooster Geologists » Carboniferous

    Last week’s specimen was a Lower Carboniferous fossiliferous siderite concretion from an unknown location, but likely from the Wooster area It was donated to the department by Emeritus Geology Professor Sam Root The concretion has beautiful crinoids preserved in it, including several stems of at least two types and three calices (crowns or.

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  • Ancient Poop or Siderite Concretions? Alleged Coprolites

    Ancient Poop or Siderite Concretions? Alleged Coprolites are Picked Apart , What may look like feces could very well be a siderite nodule encapsulating a recrystallized fossil, considering the age of the specimens and the location of deposition (epeiric lagoons).

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  • Micro-scale sideritic concretions in Holocene sediments of

    Micro-scale sideritic concretions in Guadiana sediments 17 components of the heavy-density fraction are tourmalines, amphiboles, pyroxenes, garnets, staurolite, andalusite, carbonates and Fe-oxid The siderite-bearing layer in the CM5 profile does not differ from.

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  • DISTINCTIVE REMNANTS OF SIDERITE CONCRETIONS OXIDIZED

    The iron oxide remaining in the core zones of the larger concretions is pseudomorphous after siderite that was oxidized in situ (ie iron that did not diffuse outward to contribute to the rind) Siderite originally formed under reducing conditions within a confined aquifer, down-gradient from an anticline charged with CO 2 and CH 4 With.

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  • Cleaning Siderite Concretions

    Jan 19, &#; I have some siderite concretions that had been sitting open in the elements when found They have some fine, light-colored material lodged in gaps in the fossil and on the broken nodule surface.

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  • North Dakota Geologic Survey

    North Dakota, especially in the wondrously sculpted badland areas of the west, has a fantastic variety of concretions and nodul Some are the size and shape of petrified logs, while others, perched atop pedestals of softer sediments that they shield from erosion, have lens or disk shap.

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  • SIDERITE CONCRETIONS IN THE COPAN CRINOID LAGERSTÄTTE

    SIDERITE CONCRETIONS IN THE COPAN CRINOID LAGERSTÄTTE , , Palaios.

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  • Siderite

    Brown siderite concretion, this slabbed and polished on one face to show the interior Interesting for the species and measures 90 x 75 x 50 cm Shipping weight: 124 pounds Ex Renaud Vochten collection.

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  • What Is a Septarian Concretion?

    A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil Septarian concretions are concretions containing angular cavities or cracks, called "septaria" The septaria are the calcite.

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  • Wooster Geologists » Blog Archive » Wooster’s Fossil of

    The decay of their soft parts produced hydrogen sulfide gas ad carbon dioxide, triggering the geochemistry that caused the precipitation of siderite around them The hard concretion that resulted was likely in a matrix of soft shale The strength of the siderite kept the fossils from being crushed by the weight of sediment above.

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  • iron-oxide concretions and nodules

    This concretion appears to have started as a mass of pyrite crystals (iron sulfide, cubic) and is in the process of oxidizing to iron oxide This is a cluster of pyrite crystals beginning to oxidize to hematite This thing started out as a several pyrite crystals but is now largely oxidized to hematite.

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  • Fe-oxide concretions formed by interacting carbonate and

    The siderite concretion undergoes oxidative dissolution, which is possibly microbially mediated and which provides an internal source of Fe that forms an Fe-oxide crust on the outside the concretion However, a problem with this model is that no siderite concretions have been identified, neither in outcrop (6, 8, 9) nor in any deeper.

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  • Siderite

    Brown siderite concretion, this slabbed and polished on one face to show the interior Interesting for the species and measures 90 x 75 x 50 cm Shipping weight: 124 pounds Ex Renaud Vochten collection.

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  • Wooster Geologists » Carboniferous

    Last week’s specimen was a Lower Carboniferous fossiliferous siderite concretion from an unknown location, but likely from the Wooster area It was donated to the department by Emeritus Geology Professor Sam Root The concretion has beautiful crinoids preserved in it, including several stems of at least two types and three calices (crowns or.

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  • Concretions

    Concretions Composed of a carbonate mineral such as calcite A concretion is a compact mass of mineral matter, usually spherical or disk-shaped, embedded in a host rock of a different composition.

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  • The Mazon Creek Lagerstätte: a diverse late Paleozoic

    (c) Hypothesized sequence of events required for preservation in siderite concretions (i) After rapid burial, decay of the organisms creates a geochemical microenvironment around the carcass and depletes interstitial sulphate (ii) Siderite precipitation creates a ‘proto-concretion’ that acts to entomb the organism and resists compaction.

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  • "Iron concretions in the Cretaceous Dakota Formation" by

    The Cretaceous Dakota Formation contains abundant iron oxide concretions The precursors to the iron concretions are siderite (FeCO3) nodules that formed in a reducing floodplain environment A variety of concretion morphologies formed when the precursor siderite nodules were dissolved by oxidizing groundwater in a paleoaquifer Iron-oxidizing bacteria are able to oxidize aqueous Fe(II) to Fe.

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  • Ancient Poop or Siderite Concretions? Alleged Coprolites

    Ancient Poop or Siderite Concretions? Alleged Coprolites are Picked Apart , What may look like feces could very well be a siderite nodule encapsulating a recrystallized fossil, considering the age of the specimens and the location of deposition (epeiric lagoons).

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  • Crystals & Minerals: a Siderite Concretion

    Siderite Concretion, Salmon Creek, Thurston Co, Washington These interestingly shaped nodular concretions are often called coprolite, or pseudo-coprolite They are from the Miocene age Wilkes formation, of the southwestern area of the state, and probably not true fossil dung.

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  • Concretions Picture Gallery

    May 25, &#; Most often the cementing mineral is calcite, but the brown, iron-bearing carbonate mineral siderite is also common Some concretions have a central particle, such as a fossil, that triggered the cementation Others have a void, perhaps where a central object dissolved away, and others have nothing special inside, maybe because the cementation.

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