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Namacalathus

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Journal Article
Journal: Geology
Published: 01 May 2003
Geology (2003) 31 (5): 431-434.
...Joachim E. Amthor; John P. Grotzinger; Stefan Schröder; Samuel A. Bowring; Jahandar Ramezani; Mark W. Martin; Albert Matter Abstract Biostratigraphic, carbon isotope, and U-Pb zircon geochronological data from the Ara Group of Oman indicate an abrupt last appearance of Cloudina and Namacalathus...
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Journal Article
Journal: Geology
Published: 01 December 2001
Geology (2001) 29 (12): 1091-1094.
... of complex sinuous, plate-like stromatolites (cf. Platella ), and intervening planar to curviplanar pockets filled with packstone and wackestone crowded with Namacalathus and Cloudina , presumed calcified metazoans of uncertain biological affinities. Preservation is best in limestone, and the shells...
FIGURES
Series: Geological Society
Published: 01 January 2017
DOI: 10.1144/SP448.1
EISBN: 9781786202932
... Abstract Terminal Ediacaran metazoan reefs ( c. 548–541 Ma) can be locally substantial and the skeletal metazoans Cloudina riemkeae, C. hartmannae, Namacalathus and Namapoikia produced diverse reef types with complex ecologies in association with varied microbialite support or influence...
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Figure 1. Location of  <b>Namacalathus</b> - Cloudina  assemblage in Miette Group,...
in > Geology
Published: 01 December 2001
Figure 1. Location of Namacalathus - Cloudina assemblage in Miette Group, Salient Mountain area, British Columbia. A: Index map and general geologic map, updated from Mountjoy (1980) . B: Generalized stratigraphic section
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Figure  8. Assemblage of calcified  <b>Namacalathus</b>  fossils within reefal and...
Published: 01 January 2000
Figure 8. Assemblage of calcified Namacalathus fossils within reefal and related thrombolitic horizons within the Nama Group. A, Namacalathus packstone illustrating a range of cross-sectional morphologies. B, Single large Namacalathus, over 2 cm in diameter. Note overgrowth of euhedral
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Figure  13. Taphonomic aspects of  <b>Namacalathus</b>.  Most of the photographs i...
Published: 01 January 2000
Figure 13. Taphonomic aspects of Namacalathus. Most of the photographs indicate the relatively flexible nature of the wall, suggesting only light mineralization at time of death. A–C, Deformational features include folds and wrinkles in walls and stems; squashed and flattened cups; cups without
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Figure  11. Diverse cross-sections of  <b>Namacalathus</b> hermanastes  might be i...
Published: 01 January 2000
Figure 11. Diverse cross-sections of Namacalathus hermanastes might be interpreted as different taxa (upper photos); however, virtual slices through the mathematical models shown in Figure 10 produce a diverse array of synthetic cross-sections (lower images) that can be used to estimate
Journal Article
Journal: Geology
Published: 01 August 2018
Geology (2018) 46 (9): 763-766.
...Sara B. Pruss; Clara L. Blättler; Francis A. Macdonald; John A. Higgins Abstract Ediacaran Cloudina and Namacalathus are among the earliest shell-forming organisms. The debated carbonate phase of their skeletons, high-magnesium calcite or aragonite, has been linked to seawater chemistry and p CO 2...
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Journal Article
Journal: Paleobiology
Published: 01 January 2000
Paleobiology (2000) 26 (3): 334-359.
...Figure 8. Assemblage of calcified Namacalathus fossils within reefal and related thrombolitic horizons within the Nama Group. A, Namacalathus packstone illustrating a range of cross-sectional morphologies. B, Single large Namacalathus, over 2 cm in diameter. Note overgrowth of euhedral...
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Figure  9. Tomographic reconstructions of the calcified fossil  <b>Namacalathu</b>...
Published: 01 January 2000
Figure 9. Tomographic reconstructions of the calcified fossil Namacalathus hermanastes. First described as having a “goblet” shape ( Grotzinger et al. 1995 ), the fossil has a well-defined stem that is attached to an outward flaring cup perforated by six or seven incurved holes, with an upper
Journal Article
Journal: Geology
Published: 01 May 2017
Geology (2017) 45 (5): 459-462.
... refute the presence of a large isotope excursion coincident with mass extinction of all Ediacaran biota. We propose a new biozone, the Cloudina - Namacalathus - Sinotubulites Assemblage Zone, to precede the known small shelly fossil (SSF) zones. These observations raise doubts as to whether there is any...
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Journal Article
Published: 15 October 2010
Canadian Journal of Earth Sciences (2010) 47 (10): 1305-1325.
... fossils, or trace fossils. The Bradgatia ? constitutes the youngest occurrence of this type of fossil, and is the first to be recorded from Laurentia, having previously been noted only in Avalonia. With Cloudina and Namacalathus in associated shallow-water platform carbonates, the Miette biota...
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Journal Article
Journal: Paleobiology
Published: 01 January 2001
Paleobiology (2001) 27 (1): 159-171.
... the contours in adjacent layers. We found that most of the fossils represent a single morphology with some well-defined characters that vary slightly among individual specimens. This fossil morphology was described by Grotzinger et al. (2000) as Namacalathus hermanastes. A mathematical description...
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Slab photos and photomicrographs of Nama Group fossils (southern Namibia). ...
in > Geology
Published: 01 August 2018
Figure 1. Slab photos and photomicrographs of Nama Group fossils (southern Namibia). A: Drill spots in Namacalathus fossil from sample OR216-D. B–D: Photomicrographs from Omkyk Member reef samples showing Cloudina , Namacalathus , and both, respectively. Relict botryoidal fabrics are present
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Figure 2. A:  Cloudina  fossils in well-developed thrombolite buildup, A3C ...
in > Geology
Published: 01 May 2003
Figure 2. A: Cloudina fossils in well-developed thrombolite buildup, A3C unit, Mukhaizna South-2 well (2756.20 m depth). B: Probable Namacalathus fossils (“N”) in well-developed thrombolite buildup, A3C unit, Mukhaizna-11 well (2458.20 m depth). Insets illustrate slices through digital
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Figure  7. Cross-sections through the mathematical model of an individual f...
Published: 01 January 2001
Figure 7. Cross-sections through the mathematical model of an individual fossil at different orientations, showing isolated components that represent portions of a contiguous fossil wall. In this figure, several features of the Namacalathus morphology are labeled
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Figure 3. Stratigraphic distribution of thrombolites,  Cloudina ,  Namacala...
in > Geology
Published: 01 May 2003
Figure 3. Stratigraphic distribution of thrombolites, Cloudina , Namacalathus , and cores. Note absence of these fossils in A4–A5 carbonate units, despite abundance of cores and presence of ecologically favorable thrombolite reefs. Absence in A0 unit likely reflects paucity of data and presence
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Figure 2. Fossiliferous carbonates in Salient  Mountain area. A: Outcrop vi...
in > Geology
Published: 01 December 2001
Figure 2. Fossiliferous carbonates in Salient Mountain area. A: Outcrop view of stromatolitic coquinoid limestone with Namacalathus - Cloudina assemblage; scale divisions are in decimeters. Distant cliff is another outcrop of thick carbonate on southeast spur of Mount Machray. B: Close-up
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Figure  8. Synthetic cross-sections, types 0–3. A, Type 0 cross-sections of...
Published: 01 January 2001
Figure 8. Synthetic cross-sections, types 0–3. A, Type 0 cross-sections of two mathematical models of Namacalathus. Notice that the interior and exterior boundaries of the walls are clearly visible in several cases, such as in the lower left corner. The fossil wall appears to be thickest
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Representative photographs of clastic-textured platform carbonates.  A)  Cr...
Published: 01 July 2004
Figure 10 Representative photographs of clastic-textured platform carbonates. A) Cross-bedded dolostone with large-scale trough cross-beds. Pencil for scale. B) Massive dolostone with moldic porosity formed by the dissolution of skeletal fragments. Inset shows details of Namacalathus