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"Cande and Kent (1995).bA typographic error in Wei (1995) has been corrected.

"Cande and Kent (1995).bA typographic error in Wei (1995) has been corrected.

4.3 Magnetostratigraphy

4.3.1 Terminology in Magnetostratigraphy

Hospers (1955) appears to have been the first to suggest the use of reversals as a means of stratigraphic correlation and Khramov (1955, 1957) undertook the first application. In his book Khramov (1958, English translation 1960) suggested the possibility of a strict worldwide correlation of volcanic and sedimentary rocks and the creation of a single geochronological paleomagnetic time scale valid for the whole Earth.

The application of the well-known principles of stratigraphy to the observed reversal sequences or magnetic properties of the strata in sedimentary records is referred to as magnetostratigraphy or magnetic stratigraphy (see review by Opdyke and Channell, 1996). Here the interest is specifically in the magnetic polarity and the term magnetostratigraphy is used to refer to the stratigraphy of observed reversal sequences. The terminology has been formalized by the IUGS Sub-Commission on the Magnetic Polarity Time Scale (Anonymous, 1979). The basic unit in magnetostratigraphy is the magnetostratigraphic polarity zone, which may be referred to simply as a magnetozone. Polarity zones may consist of strata with a single polarity throughout, they may be composed of an intricate alternation of normal and reverse units, or they may be dominantly either normal or reverse magnetozones containing minor subdivisions of the opposite polarity. Because of changes in sedimentation rate, polarity zones of the same thickness may not represent intervals of the same time, so the term polarity chron is used to represent a time interval. The recommended hierarchy in magnetostratigraphic units and polarity chron (time) units is given in Table 4.3 following Opdyke and Channell (1996).

Unlike most branches of stratigraphy, the chronologic system in use in magnetostratigraphy was established as it was being developed. Type sections

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