Page 53 - Introduction to Paleobiology and The Fossil Record

Representative
frequencies (kyr)
0.06 413
100

eccentricity
Eccentricity 0.00
24.5
41

22.0 obliquity
0.07
23
Obliquity
19
0.04 precession index
0 299 400 600 800
Time (kyr)
Precession
(a)
ammonite inoceramid planktic
1 2 δ C 3
13
zones zones forams
C. woollgari +
M. gr. P. 3
Turonian M. nodosoides M. gr. helvetica
mytiloides
F. catinus opalensis
W. devonense W. archaeo- Ce6
N. juddii cretacea
17 E M. geslinianum

Upper Calycoceras Inoceramus

49 D guerangeri pictus Ce5

Rotalipora
Acanthoceras
jukesbrownel cushmani
Inoceramus
atlanticus
46 C Middle A. rhoto- T.a Ce4
magense
Cenomanian C. inerme T.c I. schond R. reicheli 2

49 B M. dixoni Inoceramus
virgatus Ce3 Selbuchra, Crimea

Lower M.s

I. crippsi c. Ce2
S.s
51 A M. mantelli Folkestone-Eastbourne, UK
R. brotzeni
N.c Ce1
1
Inoceramus
anglicus
Albian Stoliczkaia
dispar

(b) P. buxtorfi
Figure 2.12 (a) Illustration of Milankovitch frequencies showing the relationships between eccentricity,
obliquity and precession cycles. (b) Outline stratigraphy of Cenomanian Stage Upper Cretaceous chalk
facies. Column 1, stages; column 2, cyclostratigraphy; column 3, sequences. (From Gale et al. 1999.)