Probable calcified metaphytes in the latest Proterozoic Nama Group, Namibia: origin, diagenesis, and implications

  title={Probable calcified metaphytes in the latest Proterozoic Nama Group, Namibia: origin, diagenesis, and implications},
  author={Stephen W. F. Grant and Andrew H. Knoll and G. J. Germs},
  journal={Journal of Paleontology},
  pages={1 - 18}
Samples from the Huns Limestone Member, Urusis Formation, Nama Group, at two adjacent localities in southern Namibia contain thin foliose to arched, sheet-like carbonate crusts that are 100–500 µm thick and up to 5 cm in lateral dimension. Morphologic, petrographic, and geochemical evidence supports the interpretation of these delicate crusts as biogenic, most likely the remains of calcified encrusting metaphytes. The original sediments of the fossiliferous samples contained aragonitic… 

Permineralized Fossils from the Terminal Proterozoic Doushantuo Formation, South China

Permineralized fossils of the terminal Proterozoic (600–550 Ma) Doushantuo Formation, China, provide an unusually clear window on biological diversity just before the Ediacaran radiation. In the

New Finds of Skeletal Fossils in the Terminal Neoproterozoic of the Siberian Platform and Spain

A current paradigm accepts the presence of weakly biomineralized animals only, barely above a low metazoan grade of organization in the terminal Neoproterozoic (Ediacaran), and a later, early

Patterns of phytoplankton radiation across the Precambrian-Cambrian boundary

Late Proterozoic and early Phanerozoic phytoplankton comprise a wide array of microfossils of possibly bacterial and algal affinity. Their radiation patterns around the Proterozoic-Cambrian boundary

Neoproterozoic-early Cambrian geology and palaeontology of Iberia

Abstract Neoproterozoic-early Cambrian successions in Iberia are reexamined. A gradual transition across the Neoproterozoic-Cambrian boundary is present in Central Iberia, whereas in the Cantabrian

Namacalathus-Cloudina assemblage in Neoproterozoic Miette Group (Byng Formation), British Columbia: Canada's oldest shelly fossils

The uppermost part of the Miette Group (Windermere Supergroup) in eastern British Columbia has yielded shelly macrofossils in cliff-forming biostromal carbonates (Byng Formation). The biostromes are

Record of aquatic carbonaceous metaphytic remains from the Proterozoic Singhora group of Chhattisgarh Supergroup, India and their significance

For the first time, a rich fossil assemblage of tapic carbonaceous metaphytes referable to eukaryotic algae, preserved on the bedding surface of grey carbonaceous shales belonging to Saraipali

The Precambrian–Phanerozoic and Ediacaran–Cambrian boundaries: a historical approach to a dilemma

Abstract The Cambrian was originally defined as a rock interval with a trilobite-dominated fauna that overlay a presumed biologically barren Precambrian epoch. Work to formally define the Cambrian

Evolutionary Trends in Remarkable Fossil Preservation Across the Ediacaran–Cambrian Transition and the Impact of Metazoan Mixing

A unifying model is presented that explains most of the major changes seen in fossil preservation and redox conditions across the Precambrian–Cambrian transition. It is proposed that the quality of



Genesis of stromatactis cavities between submarine crusts in Palaeozoic carbonate mud buildups

  • R. Bathurst
  • Geology, Geography
    Journal of the Geological Society
  • 1982
It is concluded that the sedimentary structure ‘stromatactis’ is a calcite cement-fill of a swarm of labyrinthine cavities developed in marine carbonate muds of Palaeozoic bioherms, commonly with

Aragonitic and high-Mg calcite caliche from the Persian Gulf-a modern analog for the Permian of Texas and New Mexico

Laminated, lacy, and pisolitic carbonate crusts have been found on and within some outcrops of Pleistocene limestones which rise above the modern sabkha surface in Abu Dhabi. These sediments are

Transformation of aragonite-dominated lime muds to microcrystalline limestones

Scanning electron microscopy of textures in several well-lithified Pleistocene “micrites” (mixed micrite and microspar) from south Florida and the Bahamas shows significant diagenetic alteration of

Calcification of Encrusting Aragonitic Algae (Peyssonneliaceae): Implications for the Origin of Late Paleozoic Reefs and Cements

ABSTRACT Encrusting aragonitic calcareous algae of the family Peyssonneliaceae are the largest group of calcified red algae outside the well-known Mg calcite Corallinaceae. They are distributed

Holocene and Pleistocene Calcareous Crust (Caliche) Profiles: Criteria for Subaerial Exposure

ABSTRACT Surficial, calcareous crust profiles, hard, irregular, subhorizontal, calcareous laminae, surrounded by crumbly, chalky carbonate, form at the surface of many limestone successions in

Microfacies and geochemistry of Middle Jurassic algal limestones from Scotland

Bathonian algal limestones from the Duntulm Formation of the Great Estuarine Group, western Scotland, are subdivided into three microfacies: cryptalgal laminites, thrombolites and

Distribution of High-Magnesium Calcite in Lime Muds of the Great Bahama Bank: Diagenetic Implications

ABSTRACT Studies of Pleistocene low-magnesium calcite analogs of Recent carbonate sediments indicate that the initial distribution of high-magnesium calcite in aragonitic sediments may play a

Primary Submarine Cements and Neomorphic Spar in a Stromatolitic-Bound Phylloid Algal Bioherm, Laborcita Formation (Wolfcampian), Sacramento Mountains, New Mexico, U.S.A.

Several mound-shaped bioherms with a maximum depositional relief of 12 m are developed within and upon a tabular limestone stratum in the middle of the Laborcita Formation (Lower Permian;

Multicellular thallophytes with differentiated tissues from Late Proterozoic phosphate rocks of South China

An assemblage of megascopic, multicellular thallophytes with well-preserved tissues and microstructures was discovered in phosphate rocks of the Late Proterozoic Doushantuo Formation (approximately