Stratal and
Facies
Anatomy of a Lower Jurassic High-rising
Carbonate
Platform (Jebel Bou
Dhar, High Atlas, Morocco), Part 2: Static Modeling
Erwin W. Adams1, Klaas Verwer2, Jeroen A.M. Kenter2, and Cathy Hollis1
1
Carbonate
Team, Shell International E&P, Rijswijk, Netherlands
2 Faculty of Earth and Life Science, Sedimentology and Marine Geology, Vrije Universiteit, Amsterdam, Netherlands
A GIS based geologic dataset was build of a Lower Jurassic
carbonate
platform outcrop (Jebel Bou Dahar, High Atlas,
Morocco). The
carbonate
platform developed on a structural high in an active rift basin and exhibits a high relief and
aggradational to backstepping margin style. The study window is located some 200 m away from the physical platform
break and an extensive fault system (probably syn-depositional fissures) crosscuts the study window. Syndepositional
gravitational collapse of the aggrading platform margin likely occurred and modified the depositional margin, as documented
by platform interior sediments being in direct contact with onlapping slope deposits. The platform drowned during the late
Pliensbachian to early Toarcian. The excellent outcrop conditions allowed comprehensive documentation of a platform
interior study window (aerial coverage of about 1 km2 with present -day canyons cutting 30 m deep into the platform) with
digital surveying technologies (DGPS and LIDAR) determining the spatial variation and quantitatively characterizing the 3 -D
stratal and
facies
architecture. This paper presents preliminary results of the methodological principles used to model this
platform interior study window comprising about 14 shoaling cycles of subtidal lagoon sediments grading into inter - and
supratidal tidal flat and sandbar deposits. We especially report on modeling and characterizing the distribution of sandbar
shoal
facies
. A semi-quantitative approach was used to characterize and link petrophysical characteristics to the mapped
depositional
facies
. Ultimately this digital outcrop model will serve as input in dynamic reservoir simulation models.