Tarfaya Early-Jurassic Marl Fm

Record of EA-1 and CHBK-1 wells (Choubert et al., 1966; LeRoy & Piqué, 2001). NOT an official name, but used here to enable a Lexicon entry and description.

Synonym:

References: Wenke, 2014

[Fig. 1. Regional crustal framework of the Moroccan Atlantic rifted-passive margin showing its three, major rifted-passive margin segments that are conjugate with eastern Canada: 1) Northern Central Atlantic; 2) Georges Bank- Tarfaya Central Atlantic, and; 3) Southern Central Atlantic (three zones modified from Nemcok et al., 2005). (Galhom, 2020).]

[Fig. 2. Schematic chrono-lithology chart from the basin to inner shelf settings of the Tarfaya Basin. (Table 6, page 110, in Wenke, 2014)

[Fig. 3. Summary chart for the Tarfaya Dakhla basin showing geologic time scale, lithostratigraphy, controlling tectonic events, and interpreted horizons (Galhom, 2020).]

[Fig. 4. Lithostratigraphy and log characteristics of the Triassic to Miocene succession at well W10, offshore Tarfaya Basin (El Jorfi et al., 2015).]

In the Early Jurassic, major transgressions switched the basin to a marine system (Ghassal et al., 2016). The inner to outer ramp depositional systems are divided into a southern part dominated by marine carbonates of well PC-1, and a northern part dominated by prograding fine to medium sandstones recognized in wells CHBK-1, CJ-1, MO-3, TTN-. In the cross-section of Wenke (2014), the basinal succession is marl, whereas the middle to inner shelf is sandy claystone. The entire Lower-Middle Jurassic is about 2000 m thick (fig. 4 of El Jorfi et al., 2015).

but the major basal unconformity (IDU) implies termination during late Pliensbachian in the basin, but an earlier onset as early as Hettangian in the inner shelf regions. A generalized termination of base Pliensbachian is used here for schematic graphics. A small compensation is included for the basal Peak Spreading Unconformity (PRU)

Shallow-marine setting and a sea-level fall during this period (El Jorfi et al., 2015). The Early Jurassic witnessed tectonic instability due to the initiation of continental drifting. This tectonic setting was responsible for the development of carbonate ramps in the Early- to Mid- Jurassic followed by regressive marine siliciclastic environments (Ghassal et al., 2016).