Biostratigraphy

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biostratigraphy

[¦bī·ō·strə′tig·rə·fē]
(paleontology)
A part of paleontology concerned with the study of the conditions and deposition order of sedimentary rocks.

Biostratigraphy

 

a branch of stratigraphy which studies the distribution of fossil remains of organisms in sedimentary deposits with the object of determining the relative age and the correlations between layers of the same age in different territories. The task of biostratigraphy is the elaboration of scales of the relative age of layers (in various degrees of detail and of various scopes, but in zonal layers in particular). The succession of biostratigraphic zones reflects the change in geological cross section of fossil remains from a group of extinct organisms of different taxonomic classes or their systems. Of special importance in the differentiation of zones, and above all of biozones, are groups of extinct organisms that had relatively short life-spans but that attained widespread distribution, significant abundance, and variety (for example, nummulites, graptolites, and dinosaurs). Zones are frequently based on stages in the evolution of certain rapidly changing groups of extinct organisms (for example, corals of the subclass Rugosa). The study of the remains of ancient microscopic organisms (micropaleontology), the quantity of which can be extremely large even in small specimens (for example, from deep chinks), is important for the goals of biostratigraphy. Remnants of planktonic organisms (foraminifers, algae, and others) that were carried for great distances by currents allow zones of great territorial expanse to be distinguished. Fossil remains of plant spores and pollen, which were carried for great distances by the wind, are important for correlating deposits of maritime or continental origin that are of the same age. Biostratigraphy makes broad use of the methods of paleoecology for reconstructing the conditions under which ancient organisms existed in order to distinguish complexes of organisms of the same age living in different conditions from complexes of organism of different ages living in similar conditions.

REFERENCES

Menner, V. V. “Biostratigraficheskie osnovy sopostavleniia morskikh, lagunnykh i kontinental’nykh svit.” Tr. geologicheskogo instituta AN SSSR, 1962, issue 65.
Stratigraficheskaia klassifikalsiia, terminologiia i nomenklatura. Leningrad, 1965.
Stepanov, D. L. Printsipy i metody biostratigraficheskikh issledovanii. Leningrad, 1958.

R. L. MERKLIN

References in periodicals archive ?
There is a potential to solve this biostratigraphical ambiguity by obtaining more fossil material from the stratotype section in Sweden.
The role of chronostratigraphy, however, should not be over-estimated in regional stratigraphy, particularly in cases where appropriate biostratigraphical and lithostratigraphical units can be used.
Biostratigraphical studies demonstrate it is below the Olduvai event, where the faunal break of Mn-17 (Mimomys reidi, Gacela borbonica, Equus stenonis vireti) is replaced by the BL-5 fauna.
Firstly, much detailed biostratigraphical, but also chemostratigraphical and sedimentological background information is available from other coeval Estonian sections and elsewhere in the world.
Earlier age-estimates for this level were based on biostratigraphical evidence, mainly by correlating the types of microfauna found in the TD6 horizon with early Middle Pleistocene faunas outside Iberia, such as Sussen-born (Germany) and West Runton (England), both of which are around 500,000 years old.
In South China the Asaphellus inflatus-Dactylocephalus Biozone is recognized as the second biostratigraphical unit for the Tremadocian (Peng 1990a; Zhou & Zhen 2009).
In section 3 we survey the biostratigraphical position of important mammalian assemblages (from both archaeological and non-archaeological sites), while section 4 reviews early sites in central and northwestern Europe.
The core samples were given to the palaeontologists of the Institute of Geology for preparation, identification of fossils, biostratigraphical study, and correlation of the core sections.