318
K. Leyrer· C. Strohmenger . K. Rockenbauch . T. Bechstaedt
quencyof 167 ka and an amplitude of about 8 m (Table 2). According to observed
Ca2 facies patterns, they had to be chosen as sawtooth-cycles with their peak at
80% of first segmentation. In contrast to the fourth-order cycles no phase shift
was used. However, the in-situ sedimentary preservation of fifth-order parasequences clearly depends on their position on the sea-level curve, which is mainly
determined by third- and fourth-order rises and falls. In slope areas, fifth-order
cycles (typically short-term sea-level rises) often result in increased slump and
turbidite rates (e.g. Ca2 cycle la, Ib) due to their unstable position and unfavourable water energy regimes. Furthermore, simulations show that the effects of
fifth-order (and higher-order) sea-level fluctuations often are strengthened by
fluctuations of fourth- and lower-order cycles, which has to be taken into account when analyzing Ca2 facies patterns.
Very likely, the described fifth-order parasequences are superimposed additionally by higher-order cycles. These higher-orders were not considered in the
simulation, since no correlatable periodic sedimentary evidence can be found in
the studied Ca2-cores. The reconstructed Ca2 sea-level, which consists of four
combined and superimposed cycles (Table 2), shows a strikingly good fit to the
Ca2 data set.
3.4
Sediment Production Rates
Within PHIL 5.1, carbonate production is mainly a function of water depth and
is defined as an exponential distribution curve. For production rates, PHIL 5.1
assumes three main sedimentation realms: shelf, shelf margin and the periplatform area. Each of the three has its own distribution curve, whose shape is governed by the rate and depth of maximum sedimentation, and the width of the
production function. As shown in Fig. 3, the assumed carbonate production
rates used for the simulation of the Ca2 differ considerably in their spatial distribution. Simulation shows that sediment production during Ca2 time in
Northwest Germany generally exceeds that of eastern Germany by about three
to four times and is estimated at about 70 cm/ka in shelf areas, 60 cm/ka in shelf
margin areas and 20 cm/ka in periplatform settings. These data are only valid
during Zechstein sequence ZS3 transgressive and highstand systems tracts because production rates decrease during the last 500 ka of Ca2-sedimentation
(LST and TST of Zechstein sequence ZS4) in Northwest Germany. Production
rates during the LST of Zechstein sequence ZS4 are estimated to be 50 cm/ka in
shelf settings, 40 cm/ka in shelf margin depositional environments and about 10
cm/ka in periplatform areas. Due to the fact that the actual eastern German Ca2
sediments are generally thinner, the production rates are assumed to be considerably lower than those of Northwest Germany. Furthermore, the simulated sedimentary successions of late Ca2 age (LST and TST of Zechstein sequence ZS4)
in eastern Germany indicate no substantial change in Ca2 carbonate production
rates. The production rates in the simulated eastern German setting are estimated to be about 20 cm/ka in shelf environments, 15 cm/ka in the shelf margin ar-
K. Leyrer· C. Strohmenger . K. Rockenbauch . T. Bechstaedt
quencyof 167 ka and an amplitude of about 8 m (Table 2). According to observed
Ca2 facies patterns, they had to be chosen as sawtooth-cycles with their peak at
80% of first segmentation. In contrast to the fourth-order cycles no phase shift
was used. However, the in-situ sedimentary preservation of fifth-order parasequences clearly depends on their position on the sea-level curve, which is mainly
determined by third- and fourth-order rises and falls. In slope areas, fifth-order
cycles (typically short-term sea-level rises) often result in increased slump and
turbidite rates (e.g. Ca2 cycle la, Ib) due to their unstable position and unfavourable water energy regimes. Furthermore, simulations show that the effects of
fifth-order (and higher-order) sea-level fluctuations often are strengthened by
fluctuations of fourth- and lower-order cycles, which has to be taken into account when analyzing Ca2 facies patterns.
Very likely, the described fifth-order parasequences are superimposed additionally by higher-order cycles. These higher-orders were not considered in the
simulation, since no correlatable periodic sedimentary evidence can be found in
the studied Ca2-cores. The reconstructed Ca2 sea-level, which consists of four
combined and superimposed cycles (Table 2), shows a strikingly good fit to the
Ca2 data set.
3.4
Sediment Production Rates
Within PHIL 5.1, carbonate production is mainly a function of water depth and
is defined as an exponential distribution curve. For production rates, PHIL 5.1
assumes three main sedimentation realms: shelf, shelf margin and the periplatform area. Each of the three has its own distribution curve, whose shape is governed by the rate and depth of maximum sedimentation, and the width of the
production function. As shown in Fig. 3, the assumed carbonate production
rates used for the simulation of the Ca2 differ considerably in their spatial distribution. Simulation shows that sediment production during Ca2 time in
Northwest Germany generally exceeds that of eastern Germany by about three
to four times and is estimated at about 70 cm/ka in shelf areas, 60 cm/ka in shelf
margin areas and 20 cm/ka in periplatform settings. These data are only valid
during Zechstein sequence ZS3 transgressive and highstand systems tracts because production rates decrease during the last 500 ka of Ca2-sedimentation
(LST and TST of Zechstein sequence ZS4) in Northwest Germany. Production
rates during the LST of Zechstein sequence ZS4 are estimated to be 50 cm/ka in
shelf settings, 40 cm/ka in shelf margin depositional environments and about 10
cm/ka in periplatform areas. Due to the fact that the actual eastern German Ca2
sediments are generally thinner, the production rates are assumed to be considerably lower than those of Northwest Germany. Furthermore, the simulated sedimentary successions of late Ca2 age (LST and TST of Zechstein sequence ZS4)
in eastern Germany indicate no substantial change in Ca2 carbonate production
rates. The production rates in the simulated eastern German setting are estimated to be about 20 cm/ka in shelf environments, 15 cm/ka in the shelf margin ar-