410
a
b
DRILL HOLES
BASEMENT
VERTICAL EXAGGERATION x 50
JURASSIC
C
0
BASEMENT
2
4
6
VERTICAL
EXAGGERATION x 25
8
10
0
100 km
ß= 1.0
/1.2
to
Fig. 8.17. 3 Synthetic stratigraphie cross section of
Atlantic passive continental margin, coastal plain and
shelf region off New Jersey. Two-Iayer flexuralloading model, thinning of elastic lithosphere begins
landward of hinge zone (cf. Fig. 8.16; after Steckler
et al. 1988). Note pinching out of Jurassie sediments
beneath coastal plain and onlap of early Cretaceous
onto basement. b Observed New Jersey section
thiekness of the eontinental erust (31.2 km) is
thinned to average oeeanie erust thickness (5.0 km).
The syn-rift sediments also reaeh great thicknesses
on the 100 km wide hinge zone (ß=1.2 to 1.6). The
thiekness and extent (200 km) of the landward sedii
o
Chapter 8 Subsidence
o
2
4
6
8
10
km
STRETCHED CRUST
100
2DO km
VERTICAL EXAGGERATION x 25
based on drill holes. c Southern Australian margin,
one-Iayer model, stretching factor (ß=6.2) seaward of
the hinge zone larger than in 3, where ß=4. Onlap of
post-rift sediments onto basement where no stretching occurred (ß=1); both subsidence and sedimentation rates decrease versus time. (After Hegarty et al.
1988)
ment wedge is less than in the previous example,
probably due to the wide hinge zone.
Some simulated teetonic subsidence curves were
eompared with results of geohistory analyses
(baekstripping) using information from drill holes on