Changes

==Transgressive and highstand systems tracts==

==Transgressive and highstand systems tracts==

Accommodation rates are high during transgressive–early highstand episodes of sea level, forming thick reservoirs of excellent quality. Shales in the upper transgressive systems tract and lower highstand systems tract are generally high-quality seals. Updip and bottom seals can be a problem for stratigraphic traps. Unconformity truncations, onlapping sands, and mounded shoreline sands form stratigraphic traps. Siliciclastics of the late highstand generally are poor reservoirs. Excellent source rocks are associated with the starved portion of the transgressive and early highstand systems tracts. Coals and terrestrial source rocks also are associated with the transgressive and early highstand systems tracts.

Accommodation rates are high during transgressive–early highstand episodes of sea level, forming thick reservoirs of excellent quality. Shales in the upper transgressive systems tract and lower highstand systems tract are generally high-quality seals. Updip and bottom seals can be a problem for stratigraphic traps. [[Unconformity]] truncations, onlapping sands, and mounded shoreline sands form stratigraphic traps. Siliciclastics of the late highstand generally are poor reservoirs. Excellent source rocks are associated with the starved portion of the transgressive and early highstand systems tracts. Coals and terrestrial source rocks also are associated with the transgressive and early highstand systems tracts.

==Lowstand systems tracts==

==Lowstand systems tracts==