Nannofossil

from Wikipedia, the free encyclopedia
SEM image of a coccolith of Coccolithus pelagicus from a sediment drill core of the Deep Sea Drilling Project
SEM image of a diatom from a sediment core of the Deep Sea Drilling Project

A nannofossil ( Gr . Nannos , nanos "dwarf", Latin : fossilis "excavated") is a fossil less than three hundredths of a millimeter in length. These tiny fossils can usually only be made visible with the help of electron microscopy (SEM).

The division of fossils into different size classes is arbitrary and fluid and comes from research practice. The larger microfossils are examined with light microscopic methods and macrofossils can be seen with the naked eye .

The nannofossils include many species of the unicellular phyto- and nannoplankton , whose hard mineral shells have been preserved in the rock. Typical nannofossils are the calcareous cysts of the dinoflagellates , the coccolith- forming calcareous scales (coccoliths) of the haptophyta (coccolithophorida) and the pebbly silicoflagellates . Many protophytes with shells made of organic material are also nannofossils.

Nannofossils are important key fossils in marine sediments of the Late Mesozoic and Cenozoic Era .

literature

  • Fritz-Nielsen Wissing, Ekkehard Herrig: Working techniques of micropalaeontology. An introduction . 1st edition. Ferdinand Enke Verlag, Stuttgart 1999, ISBN 3-432-29641-X .
  • Lexicon of Geosciences . Spektrum Akademischer Verlag GmbH, Heidelberg 2002, ISBN 3-8274-0427-4 .

Web links