Changes

==General characteristics==

==General characteristics==

During greenhouse times, third- through fifth-order cycles of sea level change because of little or no polar ice, and they tend to have high frequency and low amplitude. Read (1996) lists the general characteristics of carbonate platforms deposited during these cycles:

During greenhouse times, third- through fifth-order cycles of sea level (see [[Hierarchy of sequences]]) change because of little or no polar ice, and they tend to have high frequency and low amplitude. Read<ref name=ch09r49 /> lists the general characteristics of carbonate platforms deposited during these cycles:

* Cycles of 20 k.y. or less sometimes superimposed on 100- and 400-k.y. cycles

* Cycles of 20 k.y. or less sometimes superimposed on 100- and 400-k.y. cycles

* Peritidal parasequences with regionally extensive tidal flat caps

* Peritidal parasequences with regionally extensive tidal flat caps

* High-relief buildups absent from the platform top

* High-relief buildups absent from the platform top

* Parasequences with layer cake stacking patterns

* Parasequences (see [[Fourth- and fifth-order sequences (Parasequences)]] with layer cake stacking patterns

* Reef and/or grainstone facies of platform margins with limited lateral [[migration]], thick and poorly partitioned or highly compartmentalized

* Reef and/or grainstone facies of platform margins with limited lateral [[migration]], thick and poorly partitioned or highly compartmentalized

* Relatively poorly developed cycle-capping disconformities

* Relatively poorly developed cycle-capping disconformities

==Arid zone characteristics==

==Arid zone characteristics==

Carbonates deposited in arid zones during greenhouse times generally have the following characteristics (Read, 1996):

Carbonates deposited in arid zones during greenhouse times generally have the following characteristics<ref name=ch09r49 />:

* Oolitic and cryptalgal mound facies with intertidal laminite caps

* Oolitic and cryptalgal mound facies with intertidal laminite caps

==Contrasting arid and humid zone cycles==

==Contrasting arid and humid zone cycles==

[[file:predicting-reservoir-system-quality-and-performance_fig9-81.png|thumb|{{figure number|1}}Modified. Copyright: Read, 1995; courtesy SEPM.]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-81.png|thumb|{{figure number|1}}Modified from Read.<ref name=ch09r49 /> Courtesy SEPM.]]

The diagram in [[:file:predicting-reservoir-system-quality-and-performance_fig9-81.png|Figure 1]] contrasts low-amplitude carbonate arid zones sequences with humid zone sequences.

The diagram in [[:file:predicting-reservoir-system-quality-and-performance_fig9-81.png|Figure 1]] contrasts low-amplitude carbonate arid zones sequences with humid zone sequences.