Microfossil
A microfossil is a fossil between three hundredths of a millimeter and one millimeter in size . Such remains from the microcosm are examined in the context of micropalaeontology using light microscopy , the magnification factor is usually between 5 and 100. The boundaries between the smaller nannofossils and the larger macrofossils are fluid.
Microfossil groups
The microfossils include - apart from the large foraminifera - among others " protists " (single cells with a cell nucleus), tintinnids , ostracods , tentaculites and, if the size is appropriate, isolated remains of larger organisms such as sponge needles and conodonts , otoliths , fish scales , teeth and other remains small vertebrates (microvertebrates).
Geological importance
Microfossils are indispensable for the relative age determination ( biostratigraphy ) of sedimentary rocks from the Cambrian ( small shelly fauna ) to today. They are also important indicators for the reconstruction of the distribution of land and sea ( paleogeography ), for the exploration of the oceans ( paleo-oceanography ), for the description of fossil aquatic habitats ( paleo-environment ) and for the climate development ( paleoclimatology ) of the earth. With the help of the temperature-dependent discoloration of conodonts (conodont alteration index) , the thermal fate of sedimentary rocks can be traced, a fact that is important when searching ( prospecting ) for oil and natural gas deposits in applied geology ( deposit science ).
