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Assorted References

earth sciences
- In geology: Paleontology
  …and on different continents, involves stratigraphic correlation from place to place. Although correlation of strata over modest distances often can be accomplished by tracing particular beds from place to place, correlation over long distances and over the oceans almost invariably involves comparison of fossils. With rare exceptions, fossils occur only…
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use of Platystrophia
- In Platystrophia
  …fossil that is useful for stratigraphic correlations.
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geological time scale

In geochronology: William Smith’s work with faunal sequence
…this information to effect a correlation among various localities he had studied. The consistency of the relationships that Smith observed eventually led him to conclude that there is indeed faunal succession and that there appears to be a consistent progression of forms from more primitive to more advanced. As a…
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In dating: Principles and techniques
Correlation is, as mentioned earlier, the technique of piecing together the informational content of separated outcrops. When information derived from two outcrops is integrated, the time interval they represent is probably greater than that of each alone. Presumably if all the world’s outcrops were integrated,…
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Carboniferous Period
- In Carboniferous Period: Correlation of Carboniferous strata
  The type region for the Mississippian Subsystem lies in the central Mississippi Valley of the United States. Most of the formations representing the type sequence are found in Missouri, Iowa, and Illinois. The Kinderhookian Series includes the Hannibal Formation…
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Devonian Period
- In Devonian Period: Correlation of Devonian strata
  Most groups of fossil forms contribute to the establishment of a faunal and floral chronology that enables Devonian rocks to be correlated. For the continental deposits, fish and plant spores are most important. The fishes give a very precise zonation in…
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Ordovician Period
- In Ordovician Period: Correlation of Ordovician strata
  Correlation, or the demonstration of the age equivalence, of strata in the Ordovician System has traditionally relied on fossils. Shelly fossils, such as brachiopods (lamp shells) and trilobites, have proved most useful for correlation within individual continents because of their tendency…
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Paleozoic Era
- In Cambrian Period: Correlation of Cambrian strata
  Time correlation of Cambrian rocks has been based almost entirely on fossils. The most common fossils in Cambrian rocks are trilobites, which evolved rapidly and are the principal guide fossils for biostratigraphic zonation in all but rocks below the Atdabanian Stage or those of equivalent age.…
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Precambrian
- In Precambrian: Age and correlation of granulite-gneiss belts
  It is impossible to correlate the rocks in different granulite-gneiss belts. One granitic gneiss is essentially the same as another but may be of vastly different age. There is a marked similarity in the anorthosites in various belts throughout the world, and their similar relationship with the gneisses suggests…
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- In Precambrian: Correlation of Precambrian strata
  The fact that Phanerozoic sediments have been so successfully subdivided and correlated is attributable to the presence of abundant fossil remains of life-forms that evolved and underwent changes over time. Precambrian sediments lack such fossils, thus preventing any comparable correlations. There…
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Quaternary
- In Quaternary: Correlation of Quaternary deposits
  Correlation of Quaternary terrestrial sedimentary deposits has long been a challenge. It is easy in some areas to map terminal moraines as they trace across the landscapes of Indiana and Ohio, or from Denmark through northern Germany into Poland and
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Silurian Period
- In Silurian Period: Correlation of Silurian strata
  The most-challenging goal in stratigraphy is to identify on a global basis all those rocks formed during the shortest possible interval of geologic time. Correlation of Silurian strata within limits more refined than a stage (or its corresponding age) traditionally is…
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Triassic Period
- In Triassic Period: Correlation of Triassic strata
  Correlation is the technique of piecing together information from widely separated rock outcrops in order to create an accurate chronological profile of an entire geologic time period. In order to accomplish this, geologists attempt to measure the absolute ages of rock strata using techniques such…
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