Comparison with adjacent areas

Marls and marly limestones mark a ‘post-TuJo3’ relative sea-level rise (TST) during lower S8, while limestones and dolostones from peritidal environments and a decreasing diversity of included benthic micro- and macrofauna reflect a shallowing trend during the following HST. A clear definition of a mfs is not possible, but both systems tracts can be traced over the whole study area (sections SH, MD6, WB; Fig.

10).

Turonian Coniacian

Cenomanian

Albian -- StandardChronostrati-graphy

Gradstein et al. (1995)

Time in Ma

u

uu mm ll l

Al 11 Ce 2 Ce ¾ Ce 5 Tu 2

Tu 3 Co 1

Tu 1 Long-Term andShort-Term

Haq et al.(1987) Eustatic Curves

rise

100 95 90

- SinaiIsraelWest CentralJordan(this study)

sequenceboundaries sequenceboundaries sequenceboundaries

CeJo1 TuJo3 TuJo2CeJo3 CeJo4

CeJo2 CeUp TuSin 1 TuSin 2 TuSin 3

Tu1 Tu2

CeSin7CeSin5 CeSin6 Buchbinderet al. (2000)Bauer et al. (2002)Lewy and Avni (1988):omission surf. ArabianPlateSharland et al.(2001)

K 120 K 130 K 140

K 110 basin* maximum floodingsurfaces maximum floodingsurfaces maximum floodingsurfaces

TuJo1

98.9 (+0.6) 93.5 (+0.2) 89.0 (+0.5)

Fig. 11: Comparison between sequence boundaries of this study, Israel (Buchbinder et al.

2000, Lewy and Avni 1988) and Sinai/Egypt (Bauer 2002), and global sequence boundaries of the eustatic scheme of Haq et al. (1987).

Maximum flooding surfaces (mfs, grey columns) of this study and Sinai (Bauer 2002) are compared with mfs of the Arabian Plate (Sharland et al. 2001). All schemes are integrated into the chronostratigraphic frame of Gradstein et al. (1995) shown in the left column.

‘d’ (Naur Formation, Fig. 11). The same holds for the second sedimentary couple of Lewy (1990) and the sequences 3 and 4 (Fig. 11), while the omission surface on top of this second couple (upper Cenomanian Tamar Formation in central Israel, Lewy 1990) can be compared with CeJo4 on top of S4 in west central Jordan (Figs. 10, 11). Additionally, Lewy (1990) observed lateral lithological differences (from central to south Israel) within the multilithic units of the Cenomanian sedimentary couples (lower and middle Cenomanian). A change from sandy/clayey to more calcareousdeposits corresponds with the increase of marl and limestone lithologies towards the north and exhibits the general shallowing trend towards the coast from N/NW to S/SE along the platform. It has to be considered that the investigated major Cenomanian surfaces of west central Jordan do not exhibit any evidence of exposure. Therefore, a sea-level lowstand, as postulated by Lewy and Awni (1988) for Israel, cannot be confirmed for the equivalent Cenomanian succession in Jordan.

The upper Cenomanian omission surface of Lewy (1990, see above) lithologically and stratigraphically coincides with SB CeUp of Buchbinder et al. (2000) for Israel (Fig. 11). It correlates with SB CeJo4 from Jordan (Fig. 11). However, following the definition by Schlager (1991, 1999) and considering the lack of exposure indications, Buchbinder et al. (2000) interpret this sequence boundary (CeUp) as a drowning unconformity. Overlying outer-ramp marly deposits point to a missing LST and a rapid sea-level rise, similar to the observations in west central Jordan (transition S4 to S5, Fig. 10). Buchbinder et al. (2000) describe a hiatus for deposits of the CT-boundary interval at paleo-high positions, owing to extremely reduced sedimentation rates (condensation) during the upper Cenomanian – lower Turonian transgression and associated uplift in the northern areas. In contrast, relatively complete successions are documented from that specific boundary interval within the study area. The HST starts during the lower Turonian in central Israel (e.g. norhern Negev) but during middle Turonian times further south (southern Negev), as exhibited by the progradation of inner shelf deposits over marly outer shelf successions. In west central Jordan, a mfs is observed in places near the position of the CT-boundary.

Therefore, early HST marls/shales occur already in the lowermost Turonian and are overlain by late HST limestones (Wala Limestone Member) of lower-middle Turonian age. The established SB TeJo1 on top of these HST limestones does not find an expression in the scheme of Buchbinder et al. (2000). The subsequent SB TeJo2 and

the regarded LST (Fig. 11) are also observed in Israel (Tu1, Buchbinder et al. 2000).

A platform drowning in late Turonian times is observed in basinal areas of south Israel, evidenced by middle/outer shelf deposits and a drowning unconformity (Tu2), which was not to be recognised in central and northern Israel (Buchbinder et al.

2000). A late Turonian sequence boundary (TuJo3) is also defined (between S7 and S8) for the studied area in Jordan, without evidence of a platform drowning. In contrast, prograding and aggrading inner-platform deposits reflect uniform shallow-water conditions in all parts of the study area.

Dysoxic sedimentation on Cenomanian/Turonian platforms in Israel is described by e.g. Lipson-Benitah et al. (1990). These authors assume a three-phase northward migration of dysoxic facies into shelf basins during Cenomanian-Turonian times.

They assume a combination of a global control (oceanic anoxic event; OAE 2) and, in places, local controlling factors for the origin and distribution of the dysoxic facies.

Within the working area, a similar high-organic/dysoxic facies occurs in local depressions on the shelf and is observed in two parts of the investigated succession:

during the middle Cenomanian and during the CT-boundary interval. A northward transgression (provided that the dysoxic facies is linked to a relative sea-level rise), such as is assumed for Israel (Lipson-Benitah 1990), cannot be evidenced for the study area.

9.2 Sinai/Egypt

Three SBs (CeSin5-7, Fig. 11) are described from upper Cenomanian platform deposits in Sinai (Bauer 2002). The lower two sequence boundaries are overlain by LST deposits, which are not observed within the upper Cenomanian succession of the study area (Fig. 11). The ‘post-CeSin6’ sequence of Bauer (2002) contain similar shallow subtidal deposits, like the TST and HST deposits of S4 in west central Jordan. The mfs separates the TST and HST in both areas can be defined as upper Cenomanian, CeSin7 (Bauer 2002) and CeJo4 (this work, Fig. 11). A stratigraphical mismatch between these upper Cenomanian SBs and mfs is evident (Fig. 11), and probably finds its origin in a hiatus that encloses the uppermost Cenomanian and lower Turonian deposits in Sinai (Bauer 2002). Within the working area, however, a condensed but complete CT-succession is present (see above). The following two sequences in the Sinai area, containing SBs TuSin1 and TuSin2 (Bauer 2002) exhibit

similar steps of platform development as sequences S5-S7 of west central Jordan.

The eustatic sea-level rise during upper Cenomanian-Lower Turonian times is also reflected in Sinai, by deep-water deposits, followed by prograding shallow subtidal facies of the HST. The latter is separated by TuSin1 from LST deposits, which exhibit, in places, emersion. Sequence boundary TuJo1 and the regarded TST and HST of S6 (this work) are probably restricted to basinal areas in the study area and have no equivalent in the model of Bauer (2002). Sequence boundaries TuJo2, TuJo3 and the mfs of S6, S7 exhibit a comparable stratigraphical position as the middle and upper Turonian surfaces within the succession in Sinai (Fig. 11). The post-TuSin2 LST of Bauer (2002) cannot be traced to the working area, while the overlying TST and HST deposits from shallow subtidal and high-energy subtidal occur in both the Sinai and the study area.

A possible cause for differences between the sedimentary sequences in Sinai and west central Jordan may be the local phases of subsidence and uplift. The synsedimentary structuring of the low-angle shallow shelf overprinted in places

‘minor’ sea-level fluctuations, while major rises (e.g. upper Cenomanian) and falls (e.g. middle Turonian) left similar imprints on the neighbouring shelf areas.

9.3 Arabian Plate

Sharland et al. (2001) used maximum flooding surfaces, which separate genetic stratigraphic sequences (GSS, Galloway 1989), as the main tool for correlation instead of the sequence boundaries used in the models described before (following the scheme of Vail et al. 1977).

The upper Albian to Turonian successions of several areas on the Arabian Plate are correlated by Sharland et al. (2001). This correlation also incorporates the succession of the Jordanian area and the positions of the regarding mfs. The applied mfs are dated by Sharland et al. (2001) on the basis of biostratigraphic and sedimentological (and sequence stratigraphic) literature and assigned to the time scale of Gradstein and Ogg (1996). We integrated these surfaces into the chronostratigraphy of Gradstein et al. (1995, Fig. 11) and compared them with mfs of the newly established scheme (west central Jordan). This correlation is partly problematic, because the stated ages of mfs from Sharland et al. (2001) not always correspond with the position within the formation scheme of Jordan, which follows, e.g., Powell (1989b).

The date of the Arabian Plate mfs K110 (Fig. 11) is 101 Ma, and the surface is described as eustatically controlled with a plate-wide extension. Furthermore, the position of K110 in Jordan is assigned to the base of the lowermost limestones within the Naur Formation (Sharland et al. 2001). Within our interpretation, the first mfs is defined at the base of the lowermost limestone unit within the Naur Formation (S1, Fig. 10). Therefore, the mfs separates member ‘a’ (TST) from member ‘b’ (HST limestones). Although a late Albian age of the lowermost part of the Naur Formation is evidenced by larger foraminifer occurrences (Orbitolina texana, O. sefini) in the northern study area, an early Cenomanian age is assumed for the mfs below the overlying member ‘b’ (Figs. 10, 11). The mfs K120 of Sharland et al. (2001) exhibits a good stratigraphic match with this early Cenomanian surface in Jordan (Fig. 11), because K 120 is dated to 98 Ma. This lower Cenomanian age does not agree with the described position of K120 in Jordan, which, after Sharland et al. (2001), lies within the Fuheis shale (or base of subsurface cycle LA2, Andrews 1992). Based on ammonites and calcareous nannofossils, a middle Cenomanian age is evidenced for the deposits of the Fuheis Formation (Figs. 3, 10). The controlling mechanisms for K120 are described as a combination of eustasy and probable local subsidence (Sharland et al. 2001). This local imprint may be the cause for mismatches between different areas on the Arabian Plate.

The maximum flooding surfaces within the sequences S2 and S3 (this study), have no equivalents in the scheme of the Arabian Plate (Sharland et al. 2001).

Mfs K130 (eustatic control) with a middle Cenomanian age (95 Ma, Sharland et al.

2001) occurs in a similar stratigraphical position as the mfs within S4 (middle-upper Cenomanian; Figs. 10, 11) of the Jordanian succession. The position of K130 in Jordan is assigned to the base of subsurface cycle LA3 (Andrews 1992), which coincides with the base of shaly/bioclastic carbonates, or to shales within the Hummar Formation (Powell 1989b). Within the present scheme, the mfs is defined at the base of bioclastic, shallow subtidal limestones of the Hummar Formation (Fig.

10).

Sharland et al. (2001) date mfs K140 (eustatic control) as 93 Ma, earliest Turonian, and compare it with the flooding event within the lowermost Shueib Formation in Jordan (see also Powell 1989b). Powell (1989b) postulated that the base of the Shueib Formation coincides with the CT-boundary. Based on calcareous nannofossils and ammonites and following the model of, e.g., Basha (1979), the age

of the lower Shueib Formation is defined as upper Cenomanian within the present study. This may explain the stratigraphical mismatch between the two discussed schemes, although the lithological and facies descriptions of the mfs are very similar.

The two late Turonian mfs (within S6 and S7, Figs. 10, 11) have no equivalents within the scheme of Sharland et al. (2001).

9.4 Implications of the sequence scheme comparisons

Comparison between the sedimentary sequences in Jordan, Israel and Sinai exhibit a generally similar shelf development during Cenomanian-Turonian times. A transgressive phase during the Cenomanian includes several sedimentary sequences, which are predominantly characterised by a cyclic progradation of inner-shelf deposits over deeper-water deposits from inner/mid inner-shelf areas and by aggradation of thick HST successions, which can be traced over wide shelf areas.

Furthermore, a deepening and, in places, a drowning of the platforms (probably related to OAE 2) during the CT-boundary interval can be observed, which coincides with strongly reduced carbonate production, as well as facies and faunal changes on the shelf. A sea-level lowstand during the middle Turonian and the following transgression, resulting in a recovering of the carbonate shelf, occurs in all areas.

Nevertheless, regional differences occur in comparison with the global scheme of Haq et al. (1987), such as additional sedimentary sequences during middle to upper Cenomanian and late Turonian times within the investigated schemes. These differences are probably due to the low-angle and relatively low-relief shape of the investigated shelf areas, which are therefore also affected by minor sea-level fluctuations, but also to regional/local tectonics. Local subsidence in upper Cenomanian times is described from areas in Sinai (Bauer 2002) and west central Jordan, while uplift and drowning are in places observed in upper Cenomanian shelf deposits in Israel (Buchbinder et al. 2000). The hiatus that obscured the CT-boundary interval in Sinai is probably related to an uplift (inversion), coupled with the early Turonian LST (Bauer 2002). The succession of this time interval within the study area exhibits a phase without any or with at least reduced tectonic activities.

Local tectonic movements are also described for the Turonian (subsidence in Sinai and west central Jordan) and resulted in bathymetrical differences on the inner shelf, reflected by lithological and environmental differences.