574
At the same time, the Viking and Central graben systems in the North Sea became active and established comparatively deep water environments. The Kimmeridgian
and Tithonian organic-rich shales are regarded as the principal hydrocarbon source rocks for the North Sea oil (cf
Sect. 14.3, Fig. 14.11). In contrast, the late Jurassic ofthe
Lower Saxonian basin in Northern Germany is characterized by clasticsediments and evaporites indicating aridity.
Cretaceous. A land bridge, running frorn the
London-Brabant massif to the Bohemian massif, and
wrench faulting in the N orth Sea and north of the
land bridge led to marked differences in the upper
Jurassie and early Cretaceous basin evolution in central Europe.
While, for example, the southern (Franconian) basin went
dry at the end of the Jurassic, subsidence continued in the
Lower Saxonian basin, in the North Sea, and in the Paris
basin. Evaporite accumulation ceased due to a change to
more humid climate.
12.3.3 Summary (Mega-Rifting in Europe)
The Mesozoic sedimentary history of European
basins is strongly influenced by intracontinental
mega-rifting between the North Sea and the
western Tethys as weH as coeval c1imate change
from warm and arid to temperate and humid.
This led, at least in part, to strikingly similar
and easily corre1atable sediment successions in
various basins, particularly in the Triassie dominated by continental deposits outside the Alps.
Differential subsidence continued in the Jurassie and Cretaceous. The predominantly shaHowmarine sediments (resulting from general sea12.4 Intracontinental Sag Basins
12.4.1 Occurrence and General Characteristics
Intracontinental sag basins (or interior cratonic basins, intracratonic basins) are large, slowly subsiding,
long-lived basins (cf. Sect. 1.2). Some of them have
been referred to as aulacogens (cf. Sect. 1.2).
Intracontinental sag basins are known from all continents (Fig. l2.17a) and may accumulate thick (up to
~ 10 km), undeformed or little deformed sedimentary
successions over long periods of time (on the order
of 200 to 800 Ma). Many basins have a saucer shape,
and they range in size mostly from 2xl0 5 to 2xl0 6
km 2 •
An overview and detailed discussion of these basins has
been given by Leighton et al. (1990) and Leighton and
Kolata (1990). Basins of this type with late Proterozoic to
Chapter 12 Basin Evolution and Sediments
The lower Cretaceous Wealden facies represents sandy
to clayey nonmarine, brackish, deltaic, or coastal-marine
deposits. The overlying shallow-marine sediments consist
mainly of shale, sand, and minor proportions of carbonate
and opaline silica, but may vary significantly due to the
influence of local sediment sources. In conjunction with
the mid-Cretaceous sea-Ievel rise, and the evolution of carbonate secreting microorganisms, the sediments became
increasingly rich in carbonate.
The Jurassie sequence varies in thickness from about
400 to 600 m in southern Germany to approximate1y
1000 to 1800 m in northwestern Germany. The Cretaceous sediments in the Lower Saxonian trough may
reach more than 1500 m in thickness. If regions with
high sediment thicknesses are taken into account, the
average rate of Mesozoic subsidence was on the order of 25 mlMa.
level rise) of this time span were still affected
by structural highs, apart from c1imate change
and the establishment of new seaways.
- The thicknesses of the Triassie in Germanic
facies and those of the Jurassie and Cretaceous
largely vary in Central Europe. The average
rate of Mesozoic subsidence in the depocenters
was -25 mlMa.
Long-persisting intracontinental mega-rift basins represent a kind of transition between individual rift basins and intracontinental sag basins described below.
middle Paleozoic sediments have been described, for exampie, from northeastern Asia, around the Siberian platform,
and the southern Urals (Artyushkov and Baer 1986). The
largest basin in Asia is the western Siberian basin occupying an area of 3.4 x 10 6 km 2 • Other, mostly Precambrian to
Paleozoic sag basins are known from Africa, Australia, and
North America (e.g., the Paleozoic Illinois, Michigan, and
Williston basins, with -3-6 km of sediments; Klein and
Hsui 1987; Fisher et al. 1988; Leighton and Kolata 1990).
The largest basin in South America is the Parami basin existing since the early Paleozoic. Several, relatively small
basins ofNorth Africl,l, including the Tindoufbasin in Morocco, the western and eastern Erg (Ghadames) basins in
Aigeria and Tunisia, as well as the Murzuk and Kufra basins in Libya, developed in the early Paleozoic, and some of
them continued to subside until Neogene times (e.g.
Echikh 1998; Fekirine and Abdallah 1998; Ricbe and
Charpal 1998). The Paris basin began as a rift basin in the
late Paleozoic and is mainly filled with Mesozoic and Tertiary sediments (e.g. Perrodon and Zabek 1990).
At the same time, the Viking and Central graben systems in the North Sea became active and established comparatively deep water environments. The Kimmeridgian
and Tithonian organic-rich shales are regarded as the principal hydrocarbon source rocks for the North Sea oil (cf
Sect. 14.3, Fig. 14.11). In contrast, the late Jurassic ofthe
Lower Saxonian basin in Northern Germany is characterized by clasticsediments and evaporites indicating aridity.
Cretaceous. A land bridge, running frorn the
London-Brabant massif to the Bohemian massif, and
wrench faulting in the N orth Sea and north of the
land bridge led to marked differences in the upper
Jurassie and early Cretaceous basin evolution in central Europe.
While, for example, the southern (Franconian) basin went
dry at the end of the Jurassic, subsidence continued in the
Lower Saxonian basin, in the North Sea, and in the Paris
basin. Evaporite accumulation ceased due to a change to
more humid climate.
12.3.3 Summary (Mega-Rifting in Europe)
The Mesozoic sedimentary history of European
basins is strongly influenced by intracontinental
mega-rifting between the North Sea and the
western Tethys as weH as coeval c1imate change
from warm and arid to temperate and humid.
This led, at least in part, to strikingly similar
and easily corre1atable sediment successions in
various basins, particularly in the Triassie dominated by continental deposits outside the Alps.
Differential subsidence continued in the Jurassie and Cretaceous. The predominantly shaHowmarine sediments (resulting from general sea12.4 Intracontinental Sag Basins
12.4.1 Occurrence and General Characteristics
Intracontinental sag basins (or interior cratonic basins, intracratonic basins) are large, slowly subsiding,
long-lived basins (cf. Sect. 1.2). Some of them have
been referred to as aulacogens (cf. Sect. 1.2).
Intracontinental sag basins are known from all continents (Fig. l2.17a) and may accumulate thick (up to
~ 10 km), undeformed or little deformed sedimentary
successions over long periods of time (on the order
of 200 to 800 Ma). Many basins have a saucer shape,
and they range in size mostly from 2xl0 5 to 2xl0 6
km 2 •
An overview and detailed discussion of these basins has
been given by Leighton et al. (1990) and Leighton and
Kolata (1990). Basins of this type with late Proterozoic to
Chapter 12 Basin Evolution and Sediments
The lower Cretaceous Wealden facies represents sandy
to clayey nonmarine, brackish, deltaic, or coastal-marine
deposits. The overlying shallow-marine sediments consist
mainly of shale, sand, and minor proportions of carbonate
and opaline silica, but may vary significantly due to the
influence of local sediment sources. In conjunction with
the mid-Cretaceous sea-Ievel rise, and the evolution of carbonate secreting microorganisms, the sediments became
increasingly rich in carbonate.
The Jurassie sequence varies in thickness from about
400 to 600 m in southern Germany to approximate1y
1000 to 1800 m in northwestern Germany. The Cretaceous sediments in the Lower Saxonian trough may
reach more than 1500 m in thickness. If regions with
high sediment thicknesses are taken into account, the
average rate of Mesozoic subsidence was on the order of 25 mlMa.
level rise) of this time span were still affected
by structural highs, apart from c1imate change
and the establishment of new seaways.
- The thicknesses of the Triassie in Germanic
facies and those of the Jurassie and Cretaceous
largely vary in Central Europe. The average
rate of Mesozoic subsidence in the depocenters
was -25 mlMa.
Long-persisting intracontinental mega-rift basins represent a kind of transition between individual rift basins and intracontinental sag basins described below.
middle Paleozoic sediments have been described, for exampie, from northeastern Asia, around the Siberian platform,
and the southern Urals (Artyushkov and Baer 1986). The
largest basin in Asia is the western Siberian basin occupying an area of 3.4 x 10 6 km 2 • Other, mostly Precambrian to
Paleozoic sag basins are known from Africa, Australia, and
North America (e.g., the Paleozoic Illinois, Michigan, and
Williston basins, with -3-6 km of sediments; Klein and
Hsui 1987; Fisher et al. 1988; Leighton and Kolata 1990).
The largest basin in South America is the Parami basin existing since the early Paleozoic. Several, relatively small
basins ofNorth Africl,l, including the Tindoufbasin in Morocco, the western and eastern Erg (Ghadames) basins in
Aigeria and Tunisia, as well as the Murzuk and Kufra basins in Libya, developed in the early Paleozoic, and some of
them continued to subside until Neogene times (e.g.
Echikh 1998; Fekirine and Abdallah 1998; Ricbe and
Charpal 1998). The Paris basin began as a rift basin in the
late Paleozoic and is mainly filled with Mesozoic and Tertiary sediments (e.g. Perrodon and Zabek 1990).