High-Resolution Forward Stratigraphic Modeling of Ca2-Carbonate Platforms ...
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are characterized by clearly asymmetrically shaped (sawtooth) cycles with their
maximum after about the first quarter of their time (Table 2). This results in a rapid sea-level rise followed by a long time of slow regression during each parasequence. In sediment production terms, this means a catchup phase (production of
shallow subtidal sediments) after a lag time due to the rapid rise at the beginning
of each parasequence. About three quarters of the duration of each parasequence
is dominated by regression and is represented mostly by various intertidal deposits. Carbonate production rates during this stage are assumed to decrease progressively due to the lack of normal marine water input and high evaporation rates.
Modeling has also shown that vertical differences in water chemistry playa
major role in Ca2 sedimentation patterns in the Southern Permian Basin. Modeling results indicate a significant stratification of the water body, which results
in the sedimentation/precipitation of different lithologies during the same time.
One example of this is the precipitation of anhydrites in some deeper water areas
during parts of Ca2 time when carbonates were forming in shallow-water areas.
Core studies suggest a sea level curve with at least four different orders of fluctuations (second to fifth) with asymmetric shapes for the third, fourth and fifthorder fluctuations. Due to the lengy durations of the first and second-order sea
level fluctuations there is not much evidence for the shape of these curves during
the simulated time period. However, a second-order sea level highstand is thought
to have caused the sedimentation of the Copper Shale (Tl; Strohmenger et al.
1996a). As a consequence, the second-order sea level is characterized by a regressive development during Ca2 time. The asymmetric shape of the third, fourth and
fifth-order sea level curves is thought to be caused mainly by the isolated position
of the Southern Permian Basin, which was connected to the open marine system
Tethys in the area of southeast Poland. Both the investigated sediment successions
and the results of the stratigraphic modeling suggest a widely restricted communication between both marine systems, possibly due to barriers, which have influenced in- and outflow rates considerably. With increasing distance from the openmarine system, the imprints of these flooding events show an increasing delay in
time and a decreasing potential of preservation of at least sixth- and higher-order
cycles, which has to be taken into account in simulation procedures. The asymmetric shape of the reconstructed sea level curves are additionally emphasized by
restricted outflow rates, which led to slow and long-lasting sea level falls.
Although the simulations of the Ca2 sedimentary history cannot prove causeand-effect relationships, they give new insights into the highly complex Ca2 sedimentation system. The sensitivity to variations in input data offers possibilities
to test different depositional models and the core-analysis-based Ca2 sequence
stratigraphic framework. In addition, it allows estimation of the relative influences of sediment -controlling parameters during Ca2 time in different paleotopographic settings. The quantification of most sedimentation-relevant factors leads to an improved understanding of the complex sedimentation history
of the Ca2 and enables a considerably improved prediction of reservoir facies
distribution. Finally, it reduces exploration risks, even in largely uninvestigated
areas with few available data.
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are characterized by clearly asymmetrically shaped (sawtooth) cycles with their
maximum after about the first quarter of their time (Table 2). This results in a rapid sea-level rise followed by a long time of slow regression during each parasequence. In sediment production terms, this means a catchup phase (production of
shallow subtidal sediments) after a lag time due to the rapid rise at the beginning
of each parasequence. About three quarters of the duration of each parasequence
is dominated by regression and is represented mostly by various intertidal deposits. Carbonate production rates during this stage are assumed to decrease progressively due to the lack of normal marine water input and high evaporation rates.
Modeling has also shown that vertical differences in water chemistry playa
major role in Ca2 sedimentation patterns in the Southern Permian Basin. Modeling results indicate a significant stratification of the water body, which results
in the sedimentation/precipitation of different lithologies during the same time.
One example of this is the precipitation of anhydrites in some deeper water areas
during parts of Ca2 time when carbonates were forming in shallow-water areas.
Core studies suggest a sea level curve with at least four different orders of fluctuations (second to fifth) with asymmetric shapes for the third, fourth and fifthorder fluctuations. Due to the lengy durations of the first and second-order sea
level fluctuations there is not much evidence for the shape of these curves during
the simulated time period. However, a second-order sea level highstand is thought
to have caused the sedimentation of the Copper Shale (Tl; Strohmenger et al.
1996a). As a consequence, the second-order sea level is characterized by a regressive development during Ca2 time. The asymmetric shape of the third, fourth and
fifth-order sea level curves is thought to be caused mainly by the isolated position
of the Southern Permian Basin, which was connected to the open marine system
Tethys in the area of southeast Poland. Both the investigated sediment successions
and the results of the stratigraphic modeling suggest a widely restricted communication between both marine systems, possibly due to barriers, which have influenced in- and outflow rates considerably. With increasing distance from the openmarine system, the imprints of these flooding events show an increasing delay in
time and a decreasing potential of preservation of at least sixth- and higher-order
cycles, which has to be taken into account in simulation procedures. The asymmetric shape of the reconstructed sea level curves are additionally emphasized by
restricted outflow rates, which led to slow and long-lasting sea level falls.
Although the simulations of the Ca2 sedimentary history cannot prove causeand-effect relationships, they give new insights into the highly complex Ca2 sedimentation system. The sensitivity to variations in input data offers possibilities
to test different depositional models and the core-analysis-based Ca2 sequence
stratigraphic framework. In addition, it allows estimation of the relative influences of sediment -controlling parameters during Ca2 time in different paleotopographic settings. The quantification of most sedimentation-relevant factors leads to an improved understanding of the complex sedimentation history
of the Ca2 and enables a considerably improved prediction of reservoir facies
distribution. Finally, it reduces exploration risks, even in largely uninvestigated
areas with few available data.