The Cretaceous Gabra Formation in the Fula Depression

Muglad basin

Sudan

can be classified into seven three-order sequences.Based on the seismic reflection parameters

internal reflection configuration and external shape

five types of seismic facies are identified on the seismic reflection profiles of the Abu Gabra Formation.They are chaotic facies

paralleling and sub-paralleling sheet facies

foreset wedge facies

foreset(wedge)-filling faceis

and onlap-filling faceis.These facies may be further subdivided into nine classes in terms of their amplitudes and continuities

i.e.(1)parallel sheet facies with strong amplitude and high continuity

(2)parallel sheet facies with medium-strong amplitude and moderate-high continuity(3)sub-parallel sheet facies with me-dium amplitude and moderate-poor continuity

(4)sub-parallel sheet facies with medium amplitude and moderate-high continuity

(5)wedge-filling facies with medium-strong amplitude and moderate continuity

(6)wedge-fil-ling facies with medium amplitude and moderate-poor continuity

(7)onlap-filling facies with medium amplitude and moderate-poor continuity

(8)foreset-wedge facies with medium amplitude and moderate continuity

and(9)chaotic facies with medium amplitude and poor continuity.These seismic facies distinguish from one another ho-rizontally but show hereditability and differentiation over vertical sections.The spacial distribution of the seismic facies corresponds well with the structure and tectonic evolution of Fula depression.