Changes

The '''geographic extent''' of a petroleum system is determined at the critical moment. It is defined by a line that circumscribes the pod of active source rock and all oil and gas seeps, shows, and accumulations originating from that pod. [[:file:petroleum-systems_fig3-4.png|Figure 2]] shows the geographic extent of the fictitious Deer-Boar(.) petroleum system.

The '''geographic extent''' of a petroleum system is determined at the critical moment. It is defined by a line that circumscribes the pod of active source rock and all oil and gas seeps, shows, and accumulations originating from that pod. [[:file:petroleum-systems_fig3-4.png|Figure 2]] shows the geographic extent of the fictitious Deer-Boar(.) petroleum system.

The '''stratigraphic extent''' of a petroleum system is the span of lithological units which encompasses the essential elements within the geographic extent of a petroleum system. The stratigraphic extent can be displayed on the burial history chart and cross section drawn at the critical moment. [[:file:petroleum-systems_fig3-5.png|Figure 3]] shows the stratigraphic extent of the fictitious Deer-Boar(.) petroleum system at the critical moment.

The '''stratigraphic extent''' of a petroleum system is the span of lithological units which encompasses the essential elements within the geographic extent of a petroleum system. The stratigraphic extent is from below the pod of active source rock or the petroleum of the discovered accumulations in the system, whichever is deeper, to the top of the overburden rock.The stratigraphic extent can be displayed on the burial history chart and cross section drawn at the critical moment. [[:file:petroleum-systems_fig3-5.png|Figure 3]] shows the stratigraphic extent of the fictitious Deer-Boar(.) petroleum system at the critical moment.

==What is an events chart?==

==What is an events chart?==