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Fig. 9.5 Locations of
sections in the Sullivan
(
1965
, Table 6) database
for the Eocene used by
Hay (
1972
) for example
(see Fig.
9.4
) (Source:
Agterberg
1990
, Fig. 4.1)
9.1.4 Californian Eocene Nannofossils Example
Hay (
1972
) used stratigraphic information on calcareous nannofossils from sections
in the California Coast Ranges for example of application of his original ranking
method (see Fig.
9.5
for locations). These sections originally had been studied by
Sullivan (
1964
,
1965
) and Bramlette and Sullivan (
1961
). The distribution of Lower
Tertiary nannoplankton described in the latter three papers also was used for
example by Davaud and Guex (
1978
) and Guex (
1987
) for testing various types
of stratigraphic correlation techniques. The original paper by Hay (
1972
) resulted in
extensive discussions (e.g., Edwards
1978
; Harper
1981
) and applications of other
techniques to the Hay example (e.g., Hudson and Agterberg
1982
).
Hay (
1972
) restricted his example to Lower Tertiary nannofossils for samples
shown on Sullivan's (
1965
) correlation chart augmented by stratigraphic informa-
tion on the Lodo Gulch section from Bramlette and Sullivan (
1961
). Several of the
nannofossil taxa used are known to occur in older Paleocene strata in the Media
Ague Creek and Upper Canada de Santa Anita sections (see Sullivan
1964
).
Incorporation of this other information in the example slightly improves results of
the quantitative stratigraphic analysis with respect to lowest occurrences of
nannofossils in these two sections (see Agterberg
1990
). Tables
9.5
and
9.6
are
examples of dictionary input files used this example. Hay (
1972
) selected lowest
occurrences of nine taxa and the highest occurrence of one taxon (
Discoaster
tribrachiatus
) shown by symbols in Fig.
9.6
(Table
9.7
). Original sample location
information is shown in Fig.
9.7
for three sections. Table
9.8
contains original data
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