11.3 Dynamic Denudation Accumulation Systems
507
Foreland basin (Early to intermediate stage;
W ± constant, sediment supply variable)
- CO
~
- E
(I)
E
ce.
Cf)
200
100
Forepulge
Passive margi
sediments
b
a
High relief
I
...-J
I
I
,
,
I
I
----'"""\
, ,
,
,
f'SRme
, ,
3
\
Cf)
' .
Cf)
\
CD
\,
2 ~
"........
U
" ..c
Ic
CO
Q)
50
p<2.5 g/cm 3 ) .... /-'"
sediment
~
E 1
..:-,&.
o
10
20
Passive margin
"y'"
.,,/
30
40
50Ma
30
..c +-'
sediments
I
0..2
Q)
Cl
I
I
I
I
2
3
I
I
-- --*- Onset of crustal-+-I flexure
Overthrust---,~
load
1-"-----:-Relaxl'Itlon
Fig. 11.17. Model of subsidence history and sediment fiIling of foreland basin during one phase of
overthrusting. AiAb=l; S~e (compact)=D~e'
Idealized cross seetion; arrow mdicates location stud11.3.6 Pull-Apart Basins
Model curves of rapid initial subsidence (during
some 100 ka) of continental puIl-apart basins are
shown in Figs. 11.10b and 12.35d, where other characteristics of such basins are summarized. In spite of
a very high constant sedimentation rate (1 mlka), resulting from a high Ai Ab ratio, the basin first rapidly
deepens and then becomes slowly filled up with sediment. Further subsidence is mainly driven by the increasing sediment load. This model demonstrates that
the sedimentary history of this type of puIl-apart basin tends to begin with a lake or marine phase unless
terrestrial sediment influx is very high. Later, as a
result of both waning subsidence and increasing
drainage area (cf. Fig. 11.11 band c) the depositional
environment may become continental. The foIlowing
two modern examples display situations where such
a continental phase is not or only partiaIly realized.
ied. b Change in SR,..,e and total sediment accumulation with time. c SÜbsidence history (tectonic and
total subsidence) and basin filling. See text for further explanation
The Dead Sea
The Dead Sea-Jordan rift is a modern example of a
trans form zone which also experienced some extension (transtensional basin system, cf. Sect. 12.8).
Within this elongate rift system, several specific puIlapart basins developed, some of which are filled with
sediment but two still exist as lakes. Lake Kinneret in
the north is an open freshwater system, the Dead Sea
is closed and hypersaline, and its level lies about 400
m below sea level. The entire rift system is clearly
under-supplied with sediment. In this section the mechanical denudation-accumulation system of this area
is considered.
Most of the general characteristics of pull-apart basins described in Sect. 12.8 are also realized in the Dead Sea-Jordan rift (Fig. 11.18a) which is usually cited as an exarnple
of a complex salt deposit (cf. Sect. 2.5.2). The evaporites of
the 400 km long, narrow rift zone interfinger with fan del-
507
Foreland basin (Early to intermediate stage;
W ± constant, sediment supply variable)
- CO
~
- E
(I)
E
ce.
Cf)
200
100
Forepulge
Passive margi
sediments
b
a
High relief
I
...-J
I
I
,
,
I
I
----'"""\
, ,
,
,
f'SRme
, ,
3
\
Cf)
' .
Cf)
\
CD
\,
2 ~
"........
U
" ..c
Ic
CO
Q)
50
p<2.5 g/cm 3 ) .... /-'"
sediment
~
E 1
..:-,&.
o
10
20
Passive margin
"y'"
.,,/
30
40
50Ma
30
..c +-'
sediments
I
0..2
Q)
Cl
I
I
I
I
2
3
I
I
-- --*- Onset of crustal-+-I flexure
Overthrust---,~
load
1-"-----:-Relaxl'Itlon
Fig. 11.17. Model of subsidence history and sediment fiIling of foreland basin during one phase of
overthrusting. AiAb=l; S~e (compact)=D~e'
Idealized cross seetion; arrow mdicates location stud11.3.6 Pull-Apart Basins
Model curves of rapid initial subsidence (during
some 100 ka) of continental puIl-apart basins are
shown in Figs. 11.10b and 12.35d, where other characteristics of such basins are summarized. In spite of
a very high constant sedimentation rate (1 mlka), resulting from a high Ai Ab ratio, the basin first rapidly
deepens and then becomes slowly filled up with sediment. Further subsidence is mainly driven by the increasing sediment load. This model demonstrates that
the sedimentary history of this type of puIl-apart basin tends to begin with a lake or marine phase unless
terrestrial sediment influx is very high. Later, as a
result of both waning subsidence and increasing
drainage area (cf. Fig. 11.11 band c) the depositional
environment may become continental. The foIlowing
two modern examples display situations where such
a continental phase is not or only partiaIly realized.
ied. b Change in SR,..,e and total sediment accumulation with time. c SÜbsidence history (tectonic and
total subsidence) and basin filling. See text for further explanation
The Dead Sea
The Dead Sea-Jordan rift is a modern example of a
trans form zone which also experienced some extension (transtensional basin system, cf. Sect. 12.8).
Within this elongate rift system, several specific puIlapart basins developed, some of which are filled with
sediment but two still exist as lakes. Lake Kinneret in
the north is an open freshwater system, the Dead Sea
is closed and hypersaline, and its level lies about 400
m below sea level. The entire rift system is clearly
under-supplied with sediment. In this section the mechanical denudation-accumulation system of this area
is considered.
Most of the general characteristics of pull-apart basins described in Sect. 12.8 are also realized in the Dead Sea-Jordan rift (Fig. 11.18a) which is usually cited as an exarnple
of a complex salt deposit (cf. Sect. 2.5.2). The evaporites of
the 400 km long, narrow rift zone interfinger with fan del-