Geology Reference
In-Depth Information
(a)
Johnnie Fm-winters pass hills
Johnnie Fm-nopah range
2.5
0.8
16 m
0.7
2
0.6
1. 5
0.5
1
0.4
5m
5m
0.3
0.5
5m
5m
5m
0.2
0
6m
6m
6m
6m
0.1
6m
-0.5
0
10
15
20
25 30
Strat. pos. (m)
35
40
45
50
0
10
20
30
40
50
Strat. pos. (m)
(b)
Winters pass hills-log(G/H)
Nopah range-log(G/H)
0.035
2.5
0.03
Eccentricity
5.1m
2
0.025
Eccentricity
1. 5
0.02
16 m
0.015
99%
95%
90%
1
0.01
Obliquity
1. 1m
5.8 m
99% condence
Precession
0.6m
0.5 m
0.5
Precession
0.7m
0.6 m
95%
90%
0.005
0
0
0
0
0.5
1 1.5
Frequency (1/m)
2
2.5
0.5
1
Frequency (1/m)
1. 5
2
Figure 6.14
log
10
(G/H = goethite to hematite) as a function of stratigraphic position for the Winters Pass Hills and
Nopah Range localities (a). Both the 5-6 m and 16 m wavelengths are observable in the data series. MTM spectral
analysis of the log
10
(G/H) data series shows significant peaks at 16, 5, 1.1, and 0.6 m for the log
10
(G/H) series (b).
fully cognizant that the evolution of the Earth-Moon system is poorly con-
strained and thus obliquity and precession cannot be accurately calculated
for deep geologic time. However, Berger and Loutre (1994) indicate that
obliquity was approximately 29.9 kyr in duration and precessional periods
were 19 and 16.2 kyr long at 500 Ma.
Strong 5 m cycles and 0.6 m cycles, as well as 16 and 1 m cycles, in the
log
10
of the goethite to hematite magnetic ratio (Figure 6.14) were also
observed at both the Nopah Range and Winters Pass Hills. The 5 and 0.6 m
