# Shallow-marine depositional sequences in a transgressive mixed siliciclastic-carbonate system: The Early Jurassic Marrat Formation from central Saudi Arabia

Abdullah Al-Mojel, Philippe Razin, Yves-Michel Le Nindre, Guillaume Dera

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## To cite this version:

Abdullah Al-Mojel, Philippe Razin, Yves-Michel Le Nindre, Guillaume Dera. Shallow-marine depositional sequences in a transgressive mixed siliciclastic-carbonate system: The Early Jurassic Marrat Formation from central Saudi Arabia. Journal of African Earth Sciences, 2020, 167, 10.1016/j.jafrearsci.2019.02.011. insu-03661441

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Submitted on 10 Aug 2025

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1 Shallow-marine depositional sequences in a transgressive mixed

2 siliciclastic-carbonate system: the Early Jurassic Marrat Formation from

3 Central Saudi Arabia

4

5 Abdullah Al-Mojel¹, ², Philippe Razin², Yves-Michel Le Nindre³, Guillaume

6 Dera⁴

7
8 ¹Saudi Aramco, Dhahran, Saudi Arabia

9 ²ENSEGID-Bordeaux INP, EA4592, 33607 Pessac, France

10 ³Ph.D., Dr. Sci. Consulting Geologist, 58 rue Gustave Flaubert - 45100-

11 Orléans - France

12 ⁴GET, Université Paul Sabatier, CNRS UMR 5563, IRD, OMP, 14 Avenue

13 Avenue Edouard Belin, 31400 Toulouse, France

14
15 **Corresponding author:** E-mail: abdullah.mojel@aramco.com Present
16 address: P.O. Box 5093 Dhahran 31311, Saudi Arabia

17
18 **Keywords:** Arabian Platform, Toarcian, Epeiric sea, mixed carbonate-
19 siliciclastic systems, continental-marine transition, transgression, sequence
20 stratigraphy, Marrat Formation

21 **Abstract**

22 A high-resolution sequence-stratigraphic framework is proposed for the
23 Marrat Formation (Early to Middle Toarcian of Saudi Arabia) by presenting
24 new outcrop and shallow core sedimentological data located along a 280 km
25 long N-S transect south of Riyadh and westward subsurface correlations
26 based on gamma-ray wireline logs (200 km Ar Riyadh to Khurais Field). This
27 extended spatial cover allows the identification of a northward thickening of
28 sedimentary successions due to syndepositional differential subsidence.

29 Basically, these successions formed on low-energy falt-topped platform with
30 limited accommodation space in which mainly retrogradational and
31 aggradational stacking patterns were recorded. Overall, the evolution from
32 continental meandering fluvial deposits at the base of the formation to tidal or
33 wave-dominated siliciclastic and carbonate inner-platform deposits indicate a
progressive marine transgression that reached its maximum during the Middle
Toarcian *bifrons* Zone. In details, we identify two 3rd-order sequences that
onlap southward on to the Triassic–Jurassic unconformity. Higher-energy
siliciclastic shoreline facies were deposited in the upper transgressive
systems tract of depositional sequences during periods of high
accommodation space. The carbonate units consist of platform mud-
dominated facies and are well-developed during the maximum marine
transgressions of the two Marrat sequences. Continental red shales and
fluvial sandstone deposited in a humid and warm environment during the
Toarcian *bifrons* Zone (subvisioni Subzone) indicate a higher terrigenous
input interrupting the two maximum transgressive sequences. The sequences
were likely produced by global sea-level changes but also appear to have
been influenced by local climate changes with humid and warm conditions
during periods of regression and more arid conditions during transgressions.
This study serves as an outcrop analog, provides guidelines for hydrocarbon
exploration and improves seismic interpretations. Overall, these new facies
analysis, wireline log data, stratigraphic interpretations, and regional
correlations contribute to a broader understanding of the Early Jurassic
successions of the Arabian Platform.

1 Introduction

The Jurassic formations are one of the most economically important
stratigraphic intervals in the world (Powers, 1962; Powers et al., 1966;
Powers, 1968; Murris, 1980). Among them, the Marrat Formation (early to
middle Toarcian) consists of multiple reservoir units with effective caprocks in
the northeast of Saudi Arabia and Kuwait (cf. Alsharhan and Nairn, 1994,
59 2003; Al-Eidan et al., 2009), as well as possible source rocks reported in
60 Kuwait and Iraq (Abdullah and Connan, 2002; Aqrawi et al., 2010). The
61 sedimentary succession of the Marrat Formation was deposited in the Early
62 Jurassic on a very extensive epeiric tropical Arabian platform (Powers et al.,
63 1966; Murris, 1989) during the first major marine transgression succeeding to
64 the Triassic–Jurassic unconformity (Murris, 1980). The Marrat outcrops are
65 very well exposed in Central Arabia along the base of the Jurassic Jabal
66 Tuwaiq escarpments, which form spectacular west-facing cuestas along a
67 1000 km axis (Fig. 1).

68 The outcropping Marrat Formation was previously subdivided into three
69 mapping units based on lithostratigraphic and biostratigraphic correlations
70 (Powers et al., 1966; Powers, 1968; Manivit et al., 1990). However,
71 genetically related depositional sequences, cycle hierarchy, stacking patterns,
72 depositional environment evolution, and effects of syn-depositional tectonic
73 events were not documented in details. Therefore, our approach was to
74 analyses of sections and subsurface gamma-ray logs to generate a robust
75 high-resolution sequence-stratigraphic framework. This study serves as an
76 outcrop analog to the subsurface Marrat Formation of the Arabian Platform
77 and provides guideline for a better understanding of the paleogeographical
78 context and paleoenvironments of the Arabian shelf.

## 2 Geological Background

### 2.1 Paleogeographic and tectonic frameworks

80 The study area was located in the central part of the Arabian Platform,
81 which was an extensive epeiric (> 1000 km) epeiric continental to shallow-
83 marine platform located in the tropical belt on a passive margin facing the
84 Neo-Tethys Ocean (Murris, 1980) (Fig. 2). The study area was far from the
85 Jurassic shelf margin, which was located hundreds of kilometers to the east,
86 but closer to the exposed Precambrian Shield that was progressively
87 onlapped by the Mesozoic sediments.

88 Several important tectonic events produced major unconformities across
89 the Arabian Platform during the Mesozoic. Two of these unconformities,
90 respectively Early Jurassic and Late Jurassic-Early Cretaceous in age, delimit
91 the Jurassic Shaqra Group (Vaslet, 1987). The first one, situated at the basal
92 boundary of the Marrat Formation, corresponds to a time gap of
93 approximately 20 Myr having lead to contacts between Triassic and Toarcian
94 deposits. The tectonic control of this unconformity remains poorly understood
95 but could relat to a long period of regional uplift and erosion caused by a
96 tectonic inversion of the Karoo rifting between Madagascar and East Africa
97 (Delvaux, 2001; Baud et al., 2005; Khalifa, 2007; Pöppelreiter et al., 2018) or
98 the early detachment of the Indian Plate from the Africa/Arabia Plate
99 (Grabowski and Norton, 1995). At the top of the Marrat Formation, the
100 Toarcian–Aalenian hiatus corresponds to a major unconformity at the scale of
101 the Arabian Platform, which marks the beginning of the Middle Jurassic
102 Dhruma Formation. This non-deposition event may have resulted from a
103 major sea-level fall of around 75 m (Le Nindre et al., 1990; Al-Husseini, 1997;
104 Jacquin et al., 1998; Simmons et al., 2007; Ogg and Hinnov, 2012; Haq and
105 Al-Qahtani, 2005; Haq, 2018; Simmon and Davies, 2018), large-scale thermal
106 and tectonic uplifts (Le Nindre et al., 2003; Al-Mojel et al., 2018), or a
107 combination of both.
108 **2.2 Stratigraphy and regional depositional history**

109 The Marrat Formation was first defined by Steineke (1937) in an
110 unpublished report but its first formal definition was published by Bramkamp
111 and Steineke (in Arkell, 1952). Its lithostratigraphy was updated by Powers et
112 al. (1966) and Powers (1968) (Fig. 3), in a type section located near the town
113 of Marah in Jabal Kumayt (25° 04' N). A better-exposed reference section in
114 Khashm Ad Dhibi (24° 14' N) was described by Powers and McClure (in
115 Powers et al., 1966) and Manivit et al. (1990).

116 Powers et al. (1966) divided the formation into three informal units
117 corresponding to the Lower, Middle and Upper Marrat Formation, whose the
118 boundaries were defined using geomorphologic and lithologic criteria clearly
119 visible on the field by the distinction of three three cuestas. The boundaries
120 were slightly revised by Manivit et al. (1990) as follows:

121 **Lower Marrat Unit** (47 m thick) is bounded at the base by the Early
122 Jurassic unconformity marked by a stained iron surface on top of the Late
123 Triassic continental Minjur Sandstone. The lithology of the Lower Marrat unit
124 is made up of shale, sandstone and thin dolomitic beds with rare fauna
125 deposited in continental to intertidal-subtidal environments. No
126 biostratigraphic control on the age of this unit is available. These sedimentary
127 facies are clearly distinct of the underlying Triassic Minjur Sandstone
128 characterized by massive amalgamated fluvial braided channels associated
129 with paleosols (Issautier et al., 2012a, b; Stewart et al., 2016; Osman et al.,
130 2018).

131 **Middle Marrat Unit** (40 m thick) begins with fossiliferous and bioturbated
dolomitic limestone overlain by brick-red shale and siltstone devoid of fossils
133 record. The top of the unit is marked by calcareous shale with poor fauna
134 content. The depositional setting of this unit ranges from subtidal to intertidal
135 lagoon. The base of the unit is dated by ammonites (*Protogrammoceras* sp.,
136 *Bouleiceras* sp.), which indicate without ambiguity the early Toarcian
137 *serpentinum* Zone (Dubar and Mouterde, 1953; Fig. 3). *Metanoceras* aff.
138 *jurense*, generally assigned to the middle Toarcian in the SE of France
139 (Tintant, 1984), have also been reported but this apparent diachrony could
140 result from earlier appearances on the Arabian Platform followed by a
141 northward migration of this species during the middle Toarcian (Énay et al.,
142 1986, 1987).

143 **Upper Marrat Unit** (39 m thick) is a cliff-forming bioturbated lagoonal
144 limestone dated by ammonites (*Nejdia* sp. and *Hildoceras* sp.). The *Nejdia* sp.
145 (likely an evolved genus of *Bouleiceratineae*; Énay et al., 1986, 1987). was
146 discovered in Morocco in the middle Toarcian *bifrons* Zone (*sublevisoni*
147 Subzone), which allows an accurate dating of this unit. Above, this limestone
148 is overlain by a gypsum layer (7 m thick) that has been considered by Powers
149 (1968) as the base of the Middle Jurassic Dhruma Formation. Note that in the
150 subsurface of the Eastern Province of Saudi Arabia, the subsurface Marrat
151 reservoir is recognized as belonging to the upper part of the Marrat Formation
152 (Ayres et al., 1982 in Al-Husseini, 2009 and Manivit et al., 1990).

153 Overall, the Marrat Formation as a whole was considered as one
154 transgressive – regressive cycle by Le Nindre et al. (1990) with a maximum
155 flooding surface (MFS) at the base of the Middle Marrat (*serpentinum* Zone)
156 corresponding to UAB 4 of Haq et al. (1987) (Fig. 3). Based on a review and
157 interpretation of a single section described by Powers et al. (1966), Powers
(1968), Manivit et al. (1990), and Al-Husseini (2009) subdivided the Marrat Formation into two 3rd-order sequences (Marrat Sequence B and A) corresponding to the Arabian Orbital Sequence (AROS; depositional sequence 13.5 and 13.6) scribed to 2.4 Myr eccentricity cycles (Al-Husseini and Matthews, 2008; Al-Husseini, 2009) (Fig. 3). The transgressive system tract (TST) of the Marrat Sequence B consists of a continental shale in the Lower Marrat followed by a maximum flooding interval (MFI) corresponding to the fossiliferous and bioturbated limestone at the base of the Middle Marrat. The highstand coincides with brick-red shale and siltstone of the Middle Marrat. The Marrat sequence A includes the Upper Marrat where the TST and MFS are defined in the basal bioclastic limestone and the khaki shale with the ammonite fauna. The highstand systems tract of sequence A corresponds to the upper gypsum unit (Al-Husseini, 2009).

Based on regional correlations of the Jurassic System, Sharland et al. (2001) have placed a maximum flooding surface (MFS J10) in the middle Toarcian Upper Marrat Formation (Fig. 3). On another hand, however, the early Toarcian (*serpentinum* Zone) was selected as the main MFS of the Marrat succession (MFS J10) because the zone has maximal marine faunal diversity (Le Nindre et al., 1990; Kadar et al., 2015; Simmons and Davies, 2018).

## 3 Methods

Our sequence-stratigraphic study is based on nine detailed logged sections (totaling 600 m in thickness), located along a 280 km N-S transect south of Ar Riyadh. The names of these sections and their locations are shown in Figure 1. One shallow core (DHIBI-1) with gamma-ray logs located
183 in Khashm Ad Dhibi area near Ar Riyadh is also used in the study. The core
184 only covers the Upper Marrat Formation. The sedimentological data include:
185 mineralogy, grain types, grain size, texture, extended Dunham classification
186 (Dunham, 1962; Embry and Klovan, 1971), sedimentary structure and fossil
types and color. The vertical successions and evolution of the depositional
187 environments were analyzed in order to define and interpret sequence
188 stratigraphy.
189

190 High-resolution stratigraphic correlations were made using sequence-
191 stratigraphic concepts, physical correlations, and mapping. Applying Walther's
192 Law across the sections was not straight forward, because the platform was
193 aggradational and had limited facies migration. The outcrops are an oblique to
194 depositional strike so may have been more likely to have very gradual lateral
195 facies changes along the transect. Building the depositional model went
196 through a continuous iterative process (Kerans and Tinker, 1997) from one-
197 dimensional cycle stacking analysis and sequence boundary definition to two-
198 dimensional time line correlations and lateral facies organization.
199

200 The defined sequences were adopted in gamma-ray logs of nearby
201 subsurface wells in Ar Riyadh and Khurais Fields The sections are
202 complemented with biostratigraphic data of Manivit et al. (1990) and Hughes
203 (2009; unpublished Saudi Aramco internal report of DHIBI-1
204 micropaleontology). The stratigraphic locations of key biostratigraphic
205 elements (e.g., ammonite faunas) are shown on the cross-section (Fig. 12).
206

## 4 Facies and Depositional Environments

207 Twelve facies or facies associations have been identified from outcrop
observations (Figs. 4, 5 and 6 and 7) and are grouped into five depositional
8
208 environments based on their common depositional processes. The
209 depositional environments from proximal to distal are: fluvial, coastal plain,
210 high-energy nearshore, mixed carbonate-siliciclastic inner-platform and
211 carbonate inner-platform. Each facies association has been assigned to a
212 sub-depositional environment according to its sedimentological
213 characteristics.

214 F1: Medium to coarse grained trough/tabular cross-bedded
215 sandstone (braided fluvial system)

216 This facies is a trough and tabular cross-bedded sandstone, composed of
217 yellowish-orange to light-red, medium- to coarse-grained sandstone; sorting is
218 poor to moderate, with very coarse- to gravel-grade lag deposits occurring
219 primarily in the basal parts of the section, forming lag deposits (Figs, 4A and
220 9A). This facies occurs in multiple individual sets commonly stacked into
221 cosets, which themselves vary in thickness from 2 to 8 m, with lateral extent
222 of between 7 and 20m.

223 These trough cross-bedded deposits are of subaqueous origin and
224 represent the migration and accumulation of sandy deposits of sinuous and
225 straight-crested dune-scale bedforms (Miall, 1978; Allen, 1982; Rubin, 1987;
226 Collinson et al., 2006; Al-Masrahy and Mountney, 2015). Sharp boundaries at
227 the bottom of the channel-fill element records a scouring and eroding of the
228 underlying substrate (channel base) by flow circulation in front of the migrating
229 bedforms (Friend et al., 1979; Gibling, 2006).

230 This unit of sandstone occurs at the base of the Marrat Formation in Wadi
231 Al Jufair (Figs. 8A and 10) and Khashm Ad Dhibi North of latitude 23º 50' N
232 and in the Middle Marrat unit in Wadi Birk and Fara'id Al Ahmar (Fig. 12). The
233 sandstone overlies the Triassic-Jurassic unconformity in the northern
234 sections and are intercalated with barren red shales (F4) within the Middle
235 Marrat unit.

236 **F2: Inclined argillaceous stratified sandstone (fluvial meandering channel)**

238 This facies association is present in 0.5 to 5 m thick sharp-based lenticular
239 bodies intercalated with barren red shales within the Middle Marrat unit.
240 Lenticular, fine to medium grained sandstone units form the lower part of a
241 channel-fill sequence. The rest of the sequence is made of a fining-up
242 alternation of pale yellowish fine-grained sandstone and mud. (Figs. 5A, B, C,
243 and 9C; Table 1). The dip of these inclined stratifications is highly variable in
244 the successive stacked sequences, indicating lateral accretion processes in
245 point-bar deposits within low-energy meandering channels (cf. Thomas et al.,
246 1987).

247 These facies represent the deposition under the influence of upper flow-
248 regime conditions, in confined channel flow, during the final stage of channel
249 fill and abandonment (Miall, 1977, 1996; Bridge, 2006); the presence of clear
250 fining up and the high percentage of mud toward the top of the succession
251 suggests the deposition under the influence of upper flow-regime conditions,
252 in confined channel flow, meandering fluvial system (Olsen, 1987; Miall,
253 1996).

254 **F3: Ripple cross-laminated sandstone (fluvial overbank)**

255 This lithofacies is characterized dominantly by cross-laminated silty
256 sandstone that is light red, very fine-grained, and which occasionally
possesses dark mud drapes on some lamination surfaces. This facies is also characterized in places by ripple-form stratification. Ripple forms may occur in trains (Figs. 5D and E). This facies occurs in the upper parts of sets as packages of ripple cross-lamination and ripple-form strata 0.2 to 0.5 m thick. Ripple forms are especially well developed on upper bedding surfaces of sets. This facies is commonly closely associated with horizontally laminated sandstone facies.

This facies accumulated in subaqueous conditions (fluvial); and represents the unidirectional migration of small-scale ripple forms during waning flow regimes, this facies formed within either the upper part of the fluvial channel-fill or in non-channelized fluvial settings, i.e. overbank and natural levee deposits (McKee, 1966; Stear, 1985), under generally a slow and shallow water flow (Nichols, 2009; Banham and Mountney, 2014). This facies found in the Middle Marrat unit at the same stratigraphic level as the previous meandering channel facies association.

## F4: Red thinly laminated mudstone (flood-plain/lake)

In the northern part of the studied transect, the Middle Marrat member is mainly composed of 3 to 27 m thick homogeneous red laminated mudstone units, that are commonly laterally extensive, extending for 280 km across the entire section of the fluvial part of the outcrop. The basal and upper contacts of these units are gradational and marked by a transitional change from red to grayish green mud with about 10% of thin siltstone lamina (Fig. 5F; Table 1), this color changes may reflect weakly developed pedoturbation or fluid bleaching (Wright, 1986). The mudstone lamination indicates the deposition from very weak flow or standing water (Fisher et al., 2008). X-ray diffraction
282 analysis shows that the red shale is mainly composed by kaolinite with minor
283 amounts of illite and feldspar (Abed, 1979). The red color of clays is due to
284 the presence of hematite. The muddy intervals of flood plain origins in this
285 area are generally barren (Powers et al., 1966) and their association with
286 fluvial channel-fills and overbank deposits suggest a broad alluvial flood-plain
287 environment with probable ephemeral lake development recorded by the thin
288 silty lamination in some intervals (Willis and Behrensmeyer, 1994, Church, M.
289 2006; Fig. 5F). The high amounts of kaolinite and hematite suggest a tropical
290 equatorial paleoenvironment with very humid condition favoring chemical
291 weathering processes as laterization (Chamley, 1989; Dera et al., 2009).

292 **F5: Mottled red shale (paleosol)**

293 This facies is represented by 0.5 to 1.5 m thick muddy units and are
294 commonly capped by reddish-brown crust (oxidized). The facies mainly
295 consists of clay and silt enriched in kaolinite, hematite, and various elements
296 (Ti, Zr, Nb, and Y) indicating considerable alteration of sediment accumulation
297 under tropical conditions (Abed 1979; Kraus, 1999).

298 The muddy intervals are mottled, orange, pink and red, with root traces
299 (Fig. 5G; Table 1). This facies is associated with fluvial channel-fill deposits
300 (F2) representing the final stage of deposition, channel abondenment (Miall,
301 1996). This facies occurs in the Middle Marrat member and especially in the
302 southern outcrops that correspond to the more proximal setting. The color
303 contrasts and mottling could indicate organic oxidation in paleosol deposits
304 (Wright, 1986; Collinson, 1996; Kraus, 1999; Hatano and Yoshida, 2017).
305 **F6: Mottled bluish green shale with interbedded mudstone and**
306 sandstone (mud-flat/coastal-plain)

307 The facies association occurs as 0.5 to 17 m thick tabular units. It mainly
308 consists of bluish green shales mottled red and brown (Fig. 6A; Table 1). The
309 facies association consists of clay, silt and fine to medium sand. From
310 Khashm Ad Dhibi core (DHIBI-1), the shale is reddish brown with fissile
311 parting. The facies association is present in the Lower and Upper Marrat
312 members. In the Lower Marrat member, the shale is barren and associated
313 with thin orange dolomite, stromatolitic lime-mudstone (Fig. 6B) and mud-
314 draped cross-bedded sandstone. The associated sandstone and lime-
315 mudstone exhibit desiccation mudcracks. In the Upper Marrat member, the
316 shale is interbedded with channelized cross-bedded sandstone (F8) of tidal
317 origin. The facies association is deposited on low-energy mud flats in a
318 coastal-plain setting.

319 **F7: Bioturbated heterolithic siltstone and sandstone (mixed-**
320 flat/coastal-plain)

321 These facies association consists of tabular units 0.5 to 2 m thick
322 coarsening-upward gradational bases and sharp tops. The facies association
323 consists of siltstone to medium-grained sandstone. They are intensely
324 bioturbated mainly by horizontal burrows (Fig. 6C; Table 1), which mixed the
325 silt and sand. The facies association is developed in the Upper Marrat
326 member intercalated with the bluish green shale (F6) deposited in a tidal flat
327 environment. These facies usually grade up into tidal and/or wave influenced
328 massive sandstone (F8 to F10), which suggests a mixed tidal flat/coastal plain
329 depositional setting transitional between the wave-dominated shoreface and
330 the tide-dominated mud flats.

331 **F8: Cross-bedded sandstone with mud drapes (tidal creeks)**

332 This facies occurs in 0.5 to 1.5 m thick lenticular bodies bounded by an
333 erosional surface at the base and commonly sharp, iron stained and
334 bioturbated surface at the top. The facies is made up of medium-grained
335 sandstone including some plant debris. The deposit is characterized by
336 tabular cross-bedding and mud-draped current ripples indicating tidal
337 influence (Figs. 6D and E; Table 1). The cross-sets, in some cases, show
338 sigmoidal foresets with mud-drapes. This facies is well developed only in the
339 Upper Marrat member interbedded mainly with the mottled bluish green shale
340 (F6) and locally with bioturbated heterolithic silty sandstone (F7). The facies is
341 interpreted to be deposited in tidal creeks draining a wide low-energy lower
342 coastal plain (cf. Ginsburg, 1975; Weimer et al., 1982). The tidal influence is
343 suggested by the mud-draped current ripples and sigmoidal foresets (cf.
344 Tankard and Hobday, 1977; Banerjee, 1991).

345 **F9: Skolithos-bearing bidirectional cross-bedded sandstone (tidal bars and channels)**

347 This facies forms 0.5 to 1.5 m thick tabular to lenticular units with sharp
348 bases, and iron-stained bioturbated tops. The facies consists of medium-
349 grained sandstone including plant debris and displaying bidirectional
350 megaripple cross-bedding of tidal origin. The facies is highly bioturbated with
351 abundant *Skolithos* sp. trace-fossils (Fig. 6F; Table 1). It occurs in the topmost
352 of the Marrat Formation on top of the paleosols (F5), bluish green shale (F6),
353 bioturbated heterolithic silty sandstone (F7) and wave-influenced sandstone (F10). The facies is interpreted to be deposited in tidal bars and channels in a nearshore environment. (cf. Fery, 1975; McIlroy, 2004; Miller, 2007; Gerard and Bormley, 2008).

357 **F10: Swaley cross-stratified sandstone (shoreface)**

358 The facies occurs as 1 to 2 m thick tabular units having sharp scoured bases and bioturbated tops (Fig. 6G, H; Table 1). The facies consists of medium-grained sandstone including intraclastic reworked pebbles and are characterized by swaley cross stratification (SCS; Leckie and Walker, 1982) and some hummocky cross-stratifications (HCS; Harms et al., 1975; Leckie and Walker, 1982). Sometimes, this facies grades up to bidirectional cross-bedded tidal sandstone (F9). Otherwise, the SCS sandstones are sometimes sharply overlain by tidal creek sandy deposits (F8) bioturbated heterolithic silty sandstone (F7) or grayish green shale (F11). This facies can be interpreted as a wave and storm dominated shoreface sands (cf. Dumas and Arnott, 2006).

369 **F11: Grayish green calcareous shale (shale dominated inner-platform)**

371 The facies appears as 1 to 4 m thick olive gray to greenish gray units. They are made up of terrigenous clay and admixed carbonates (Fig. 7A; Table 2). The shales are brittle, flaggy and slabby. In core, the calcareous shale shows thin laminations, rare *Chondrites* burrows and reworked mollusk debris (Fig. 10). The calcareous shale contains gastropods, bivalves and locally ammonites (Manivit et al., 1990). The calcareous shale is mainly
377 interbedded with bioturbated quartzose lime-mudstone and mottled bluish green shale (F6), which suggest an inner platform setting close to the continental to coastal plain terrigenous source. The rare *Chondrites* burrows, rare macrofauna and the thinly laminated sedimentary structure suggest restricted conditions that could result from a sub-oxic bottom water (Bromley and Ekdale, 1984). The driving control of the restriction in such shallow water is probably the high coastal nutrient influx and the surface runoff which could cause density stratification that prevented vertical circulation of bottom water (Bottjer et al., 1986 in Read, 1989; Rabalais et al., 1991; Lukasik et al., 2000).

386 **F12: Argillaceous nodular peloidal mudstone/wackestone (mixed inner-platform)**

388 This facies occurs in 1 to 3 m thick tabular units, which are commonly bounded by sharp base and top. The base of the units are often marked by reworked intraclasts and skeletal fragments. The facies is made up of slightly argillaceous muddy carbonate facies including pellets, peloids, intraclasts, skeletal fragments and locally 20 to 50% fine to medium quartz grains. The fossil assemblage consists of ammonites, bivalves, gastropods, echinoid, brachiopods and agglutinated foraminifera such as *Ammodiscus* sp. (Manivit et al., 1990; Hughes, 2009; unpublished report DHIBI-1 micropaleontology).
389
390
391
392
393
394
395
396 The facies exhibits a nodular sedimentary structure (Fig. 7B; Table 2), argillaceous wispy lamination in core sample and thin horizontal burrows 5 mm wide (Fig. 7C). The facies is present in the upper part of the Lower Marrat and Upper Marrat units. The facies is interpreted to be deposited in a low-energy mixed inner-platform with limited siliciclastic influx. As they are localized between dark-colored calcareous shale (F11) and light-colored 400
401
402 bioturbated lime-mudstone (F13), it is interpreted to record the transition from
403 less-oxygenated to well-oxygenated conditions.

404 F13: Bioturbated peloidal wackestone/mudstone (carbonate inner-platform)

406 This facies consists of 1 to 3 m thick tabular units, with a transitional base
407 and bioturbated firmground at the top (Figs. 7C and D; Table 2). The facies is
408 made up of very fine pelletal peloidal grains. The facies is highly bioturbated
409 with branched vertical burrows (Thalassinoides) that tend to homogenize the
410 sediments and destroy the primary sedimentary structures. Moreover, they
411 may have argillaceous wispy solution seams and rare nodular sedimentary
412 structures. The fossil assemblage consists of echinoids, brachiopods,
413 molluscs (Inoceramus sp. fragments), and benthic foraminifera
414 (Siphovalvulina variabilis, Valvulina sp., Haplophragmoides ssp.,
415 Ammobaculites sp., Textulariopsis sp.) (Fig. 10; Hughes, 2009; unpublished
416 report). The facies is interbedded with the slightly argillaceous horizontal
417 limestone (F12). It is only present in the northern two sections (Fig. 12).

418 The light color of this facies and the intense bioturbation suggest a well-oxygenated environment and a relative normal marine condition (Wilson and Jordan, 1983; Galli, 1993; Khetani and Read, 2002). The foraminiferal association is considered as the most open-marine biofacies in generally restricted low-oxygenated environment (Hughes, 2009; unpublished report).

423 5 Depositional Model

424 The spatial distribution and the lateral relationships of the facies are
425 illustrated in an idealized depositional model (Fig. 11). This depositional
model is built using the sedimentological characteristics, vertical facies successions in individual logs (e.g., Figs. 9 and 10) but also the lateral organization of the facies given by the correlation established along a 280 km long transect (Fig. 12).

The depositional model represents a continental to inner-platform shallow-marine depositional settings with two depositional domains including a siliciclastic-prone proximal domain and carbonate-prone distal domain. The siliciclastic proximal domain consists of alluvial system and wide shale-prone coastal plain to inner-platform environment with limited fluvial dynamics. They are characterized by a low-energy tidal flat and occasional wave-dominated environment. In such flat inner-platform, higher-energy deposits are represented by narrow facies belt of SCS sandstone (F10) resulting from repeated marine transgressive events (cf. Wilson, 1975). The higher energy nearshore environments were better developed during periods of high accommodation rates (Late TST and MFS) in which higher water-depth favor wave propagation and stronger tidal currents. The carbonate-dominated distal domain consists of shale-prone and mud carbonate-prone inner-platform. The shale-prone inner-platform is in a relatively proximal setting influenced by siliciclastic influx, whereas carbonate-prone inner-platform representing the most open-marine environment. The carbonate inner-platform deposits (Fig. 10) show no evidence of wave-base or mid-ramp high-energy facies in a classical sense. High-energy carbonate facies in such flat inner-platform settings appears at base of the HFSs (Fig., 10) considered as transgressive reworked sediments. Interestingly, these basal grainy facies coincide with the appearance of the most open-marine biofacies (foraminifera) in generally
451 restricted low-oxygenated environment, which confirm that the waves are
452 transgressive related process. The bathymetry of the Marrat depositional
453 environments was probably never more than a few meters based on the
454 occurrence of time-equivalent fluvial facies to the south.

455 The objective of this idealized depositional model is to give a relative
456 position to each identified facies and does not indicate synchronous facies.
457 This is because the sedimentary systems kept changing through time and
458 evolved within a depositional sequence. For example, siliciclastic facies are
459 more dominant during early transgressive periods, whereas, carbonates
460 develop widely during late transgression and highstand periods.

461 **6 Sequence Stratigraphy**

462 Correlations between nine sedimentological sections in the Marrat
463 Formation result in a regional transect oriented in an oblique-dip direction.

464 The base of the transect is picked at the Triassic–Jurassic unconformity,
465 which is a sharp erosional surface at the top of the fluvial Minjur Sandstone.

466 The top of the cross section is picked at the top of the Marrat Formation,
467 which is the Early–Middle Jurassic unconformity. The unconformity is overlain
468 by local evaporites to the north and laterally continuous ferruginous oolite to
469 the south. The Middle Marrat continental red unit shows continuous extension
470 along the outcrops. The lateral facies changes in the shallow-marine
471 environment indicating an apparent S-N dip direction of the depositional
472 system.

473 The facies distribution along this regional transect shows that the Marrat
474 Formation comprises two composite sequences (MCS1 and MCS2). Each in
475 turn consists of five high-frequency sequences (HFS1 to HFS5). The first
476 composite sequence (MCS1) includes the Lower Marrat and a part of the
477 Middle Marrat unit and the second (MCS2) includes a part of the Middle
478 Marrat and the Upper Marrat units (Fig. 12). The MFS of MCS1 coincide with
479 the MFS of sequence B of Al-Husseini (2009), MFS J10 of Kadar et al. (2015)
480 and Simmons and Davies (2018). The top sequence boundary of MCS1 is
481 slightly lower than Al-Husseini's (2009) sequence boundary.

482 The composite sequences onlap southward onto the Triassic–Jurassic
483 unconformity. The regional geometry of these continental to shallow-marine
484 deposits show a clear differential subsidence along the transect with the north
485 subsiding faster than the south. This differential subsidence appears rather
486 homogeneous except between Wadi Al Jufayr and Faridat Balum where a
487 strong increase of the subsidence rate is recorded by wedging stratal
488 geometries.

489 The main maximum marine transgression is in the *bifrons* Zone near the
490 top of the Marrat Formation (MCS2). There is no evidence of progradational
491 stacking patterns or low-stand deposits as most of the accommodation space
492 remained full throughout deposition. The top of the Marrat Formation that
493 corresponds to the long-lived Aalenian hiatus and probable subaerial
494 exposure does not exhibit any fluvial incisions, indicating the lack of any
495 efficient fluvial system and probably a very flat topography at that time.

496 In the reference section (Khashm Ad Dhibi), the vertical facies
497 successions of the Marrat composite sequences are both beginning by basal
498 transgressive fluvial deposits characterized by a set of individual fluvial
499 channels interfingering with red siltstone and shale. The fluvial deposits grade
500 upward to mixed carbonate-siliciclastic coastal-plain and inner-platform facies
501 (Figs. 8 and 9). The maximum marine transgressions of these composite
502 sequences are interpreted in the clean bioturbated limestone inner-platform
503 facies (F13; Figs. 8, 9 and 10). These MCS are clearly asymmetric in
504 thickness with a thick transgressive unit and much thinner regressive one.
505 This asymmetric pattern is related to very shallow marine conditions in the
506 inner platform where sediments are only preserved during the stage of
507 increasing accommodation space,

6.1 Marrat composite sequence 1 (MCS1)

509 Marrat composite sequence MCS1 is 85 m thick in the northern area
510 (Khashm Ad Dhibi) and thins out and pinches out at the most southern
511 section. The basal sequence boundary is the Triassic–Jurassic unconformity
512 marked by a very sharp contact (Fig. 8A), paleosol and iron-crust surfaces on
513 top of the Minjur Sandstone fluvial deposits. In the most complete sections,
514 the early TST (0 to 40 m thick) consists of a basal fluvial sandstone unit (F1)
515 overlain by barren bluish green shale coastal-plain facies (F6). It is made up
516 of at least three high-frequency sequences (HFS1 to 3) characterized by
517 asymmetrical transgressive cycles with thick basal shale deposits. HFS1 is
518 capped by a thin cross-bedded sandstone unit displaying mud-drapes and
519 mudcracks. HFS 2 and 3 are capped by thin stromatolitic lime-mudstone and
520 dolomite bed. These HFSs are aggradational at the base of the northern two
521 sections and pinch-out completely between Wadi Al Jufair and Faridat Balum
522 sections.

523 The late TST (0 to 23 m thick) of MCS1 is dominated by mixed carbonate-
524 siliciclastic inner-platform facies and made up of at least two high-frequency
525 sequences (HFS4 and part of HFS5). It starts with a thin fluvial sandstone bed
grading upward to brown shale, representing coastal-plain (F6) and to inner-platform quartzose nodular lime-mudstone (F11) interbedded with green calcareous shale (F12). The calcareous shale and the quartzose lime-mudstone grade updip into shoreface swaley cross-stratified sandstones (F10; Khashm Khalta and Khashm Disman). These shoreface sandstones form narrow high-energy wave dominated facies belt that appear during periods of relatively high accommodation rate. Further updip, there are also several fluvial units between Khashm Al Khalta and Fara'id Al Ahmar indicating a transition to nonmarine facies that are time-equivalent to the marine facies farther north. In the northern sections, the MFS is marked by inner-platform highly bioturbated peloidal lime-mudstone (F13). South of Faridat Balum section, these pure carbonate deposits grades to mixed siliciclastic-dolomitic then argillaceous facies that finally onlap directly on the Minjur Formation in Fara'id Al Ahmar section. So, even though marine conditions occurred to the north, there was still subaerial exposure to the south.

The HST of the MCS1 has a progressively lower carbonate content and consists of coastal-plain green shale (F6) that progressively grades upward into flood-plain/lake thin laminated red shales (F4) of the Middle Marrat unit. These highstand red shales form an aggradational and tabular 15 to 20 m thick unit in the northern area. It pinches out gradually southward. The sequence boundary is placed at the base of the fluvial channel-fill sandstones that are locally intercalated with the red shales.
549 **6.2 Marrat composite sequence 2 (MCS2)**

550 The MCS2 is 50 m thick in the northern area (Khashm Ad Dhibi) and thins
551 to 4 m thick to the south. The basal sequence boundary is placed at the base
552 of the fluvial channels in the Middle Marrat. The early TST is marked by
553 retrogradational stacking pattern made up of at least three high-frequency
554 sequences (HFS1 to HFS3) onlapping towards the south. They are
555 characterized by shale dominated low-energy fluvial, coastal plain and inner-
556 platform facies. The high-resolution stratigraphic correlations show that the
557 more proximal coarse-grained and cross-stratified fluvial facies are dominant
558 in Wadi Birk - Fara'id Al Ahmar, and secondarily in K. Al Khalta areas but are
559 absent in the southernmost part of the transect. They grade to more distal
560 shaly deposits northward and to lower energy fluvial deposits southward in the
561 area of minimum accommodation, but no fluvial incisions are noticed. This
562 observation suggests that the orientation of the fluvial systems is oblique to
563 the studied transect with a probable west-east component.

564 In detail, HFS1 is entirely made up of fluvial sandstone and shale deposits
565 up to 25 m thick overlain in the northern section by transgressive thin
566 reworked peloidal skeletal packstone of HFS2 (Fig. 10). HFS2 is a 9 m thick
567 symmetrical cycle and is made up of grayish green calcareous shale (F11)
568 with thin reworked skeletal intraclastic rarely bioturbated wackestones (F12)
569 (Fig. 10). HFS2 shows an increase in quartz content updip grading into fluvial
570 red shale (F3/F4) and point-bar sandstone (F2). HFS3, 2.5 to 5.5 m thick,
571 begins with sharp-based skeletal wackestone fining upward to weakly
572 bioturbated argillaceous lime-mudstone (F12) and capped by coastal-plain
573 reddish brown shale (F6) (Fig. 10). This HFS3 grades updip into well-
574 developed tidal cross-bedded sandstone (F9) and further to the south into
575 fluvial sandstone and associated red shales.

576 The late TST is made up of two backstepping HFSs (HFS4 and lower part
577 of HFS5). From north to south, the depositional system consists of several
578 facies belts: a mixed carbonate-siliciclastic (F11/F12), a narrow and localized
579 wave-dominated nearshore sandstone belt (F10), an inner platform to coastal
580 plain shale-dominated environment with tidal channel sandstones (F6 to F9)
581 and alluvial red shales and heterolithic point-bar deposits (F2 to F4). HFS4 is
582 a symmetrical transgressive-regressive sequence up to 6 m thick (Fig. 10). It
583 begins with a sharp base, overlain by argillaceous transgressive reworked
584 skeletal intraclastic wackestone (F12; Khashm Ad Dhibi) or scour-based
585 swaley cross-stratified sandstone (F10; Khashm Khalta). At the base of HFS4,
586 ammonites dated as middle Toarcian (bifrons Zone) were found in calcareous
587 shale inner-platform facies in Khashm Ad Dhibi (Manivit et al., 1990). The
588 calcareous shale (F11) grades upward to slightly argillaceous lime-mudstone
589 (F12) interpreted as the MFS of this high frequency sequence. The
590 argillaceous lime-mudstone (F12) progressively changes to coastal-plain
591 green shale (F6) and tidal sandstone (F8) without passing through high-
592 energy shoreface deposits. In the most southern sections, HFS4 consists of
593 fluvial sandstone capped by paleosol. HFS5 is a symmetrical transgressive-
594 regressive cycle ranging from 2.5 to 7 m in thickness. From north to south, it
595 begins with slightly argillaceous wackestone/packstone (F12; Khashm Ad
596 Dhibi), sharp-based wave dominated sandstone (F10; Khashm Khalta) or tidal
597 point-bar sandstone (F8; Khashm Disman).
598 Upper HFS5 (HST of MCS2) is very thin (< 5 m). It is dominated by
599 shallow-marine carbonate and sandstone with little shale content. In the
600 northern section (Khashm Ad Dhibi), it is made up of thinning-up slightly
601 argillaceous carbonate parasequences with some *Chondrites* burrows and
602 capped by a hardground surface (Fig. 10). In a more proximal position, it is
603 marked by a minor progradation of the nearshore sandstone belt (F10,
604 Khashm Khalta to Faridat Balum; Fig. 12). Then, the facies succession shows
605 a decrease of the wave influence and a relative increase of tidal processes
606 with the occurrence of bidirectional cross-bedded sandstone (Faridat Balum,
607 Khashm Khalta and Khashm Disman) and *Skolithos* sandstone with plant
debris (F9). The HST wedge out to the south where it is represented by iron-
608 stained surfaces.
609

610 The maximum transgression of the whole Marrat cycle corresponds to
611 MFS of the MCS2. In Khashm Ad Dhibi to the north, it is marked by a
612 relatively thick highly-bioturbated pelletal lime-mudstone considered as a
613 shallow-marine low-energy inner carbonate platform facies, the most distal
614 marine facies of the entire Marrat Formation (Fig. 10). It grades updip to
615 calcareous shale (F11; Wadi Al Jufayr), then to relatively higher energy sand
616 dominated shoreface to backshore/tidal flat deposits. The shoreface is
617 represented by scour-based intraclastic swaley cross-stratified sandstone
618 (F10, Faridat Balum). In a more proximal position, tidal-influenced sandstone
619 and heterolithic facies are deposited in a backshore to tidal flat environment
620 (F7 to F9; Khashm Disman to Fara'id Al Ahmar).

621 The upper sequence boundary of MCS2 is a hardground surface overlain
622 by 7 m of evaporites in the Khashm Ad Dhibi section to the north (Fig. 10).
623 Lithostratigraphically, these evaporites were considered as part of the Marrat
624 Formation (Manivit et al., 1990). However, they are not genetically related to
625 the Marrat depositional system but to the Dhruma sequence (Al-Mojel, 2017)
626 consistent with Powers (1968). This evaporitic unit is restricted to the most
627 subsided area in the north (Khashm Ad Dhibi) and is absent to the south.
628 From Faridat Balum to Abu Al Jiwar (more than 200 km long), the top Marrat
629 unconformity is overlain by a silty ferruginous oolite horizon up to 0.5 to 5 m
630 thick lying on top of the thin but highly continuous HFS5 with no evidence of
631 major erosion. This stratal continuity below and above the Early-Middle
632 Jurassic unconformity confirms the very flat topography and high stability of
633 this part of the Arabian Platform during the Aalenian period.

634 7 Discussion

635 7.1 Inner platform development

636 During the Early Jurassic, the Arabian Platform underwent gentle
637 differential subsidence. The continuous and slight subsidence controlled the
638 thickness of the strata as well as lateral facies distribution (Fig. 12). Thus, the
639 platform aggraded as a response to the rotational differential subsidence and
640 stacked thick shallow-marine deposits wedging and thickening toward the
641 depocenter.

642 At the onset of the Jurassic transgression, the Arabian Platform was a very
643 flat low-energy, shallow-marine homoclinal ramp as attested by our
644 stratigraphic transects (Fig. 12 and 13). A minor slope of 0.1 m/km is
645 calculated from the top of Marrat Formation from the shoreline (Faridat
646 Balum) to the most distal section (Khashm Ad Dhibi) in a corrected dip
direction, assuming NE dip. This flat-topped profile is mainly related to the
overall geodynamic setting, where the studied domain is located in the inner
part of a very wide epeiric platform on the Neo-Tethys passive margin with
stable tectonic context. The limited accommodation rate is compensated and
filled by siliciclastic supply and carbonate production. The very flat
depositional profile is also indicated by the large area of tidal influence in the
siliciclastic coastal plain and the meandering pattern of the fluvial system of
the middle Marrat unit. In the subsurface, the Marrat reservoir in Kuwait
consists of sheet and shoal of grainstones that are underlain and overlain by
extensive sabkha and tidal flats deposits (Al-Eidan et al., 2009). The lower
sabkha and tidal flat units in Kuwait could correlate to the lower Marrat of
Khashm Ad Dhibi that is dominated with tidal-flat stromatolite laminated
mudstone. The upper sabkha and tidal flat units in Kuwait could tie to the
crinkly laminated evaporite at the base Dhruma sequence (Fig. 13). These
extensive sabkha and tidal flats attest a predominantly flat-topped platform
during Marrat deposition. Moreover, west of the Qatar Arch in the Rub' Al-
Khali and Oman, the Marrat Formation has two distinct carbonate units that
extend for 500 km across the platform (Fig. 13; Stewart et al., 2016). The lack
of evidence of major channel incisions or prograding clinoforms during relative
sea-level fall or still stand can be also considered as a consequence of the
very low gradient with probably limited sea level changes in what were likely
greenhouse conditions (Summerfield, 1985; in Blum and Törnqvist, 2000).
Moreover, the lack of high-energy sediment transport processes and the low
sediment production, both carbonate and siliciclastic in proximal setting, led
for very low gradient depositional profile (0 to 0.4°) (Williams et al., 2011).
The Marrat Formation is characterized by low-energy mud-dominated coastal plain to inner-platform setting with limited fluvial input. Higher-energy depositional settings only occur during late TST and MFS when paleobathymetry is enough to allow wave propagation in the inner-platform setting. The coastal plain at the base of MCS1 is very low-energy marked by barren shale with thin stromatolites lime-mudstone (Fig. 10). The high-energy wave influenced siliciclastic facies (F10) appears during late transgression as short-lived wave reworking sandstone. Similarly, the MCS2 begins with low-energy shale and lime-mudstone that progressively evolved to higher-energy tidal creeks and shoreface sandstone. Generally, the tidal creeks require higher-energy to transport the sediments and to form channel-beds (Davis, 2012). Moreover, high-energy deposits resulted from repeated marine transgressive events in this kind of flat-topped wide platform with slow sedimentation rate (Wilson, 1975). During the HST, the influence of the wave decreased upward and, instead, tidal influence is preserved in sandflat with prominent bidirectional cross-bedding and *Skolithos* sandstone (most top of MCS2).

The carbonates of the Marrat Formation are low-energy mud-dominated facies with reworked skeletal intraclastic wackestone/packstone (Fig. 9). They show very consistent flat tabular aggrading units that pinch out to the south. (Fig. 12). The carbonate production in such mixed system is weak with common interbedded shales and hardground/firmgrounds early-cemented surfaces near the base of the sequences (Fig. 10; HFS2, 3 and 4 of MCS2). This low carbonate production is probably controlled by the overall restricted inner-platform condition and poorly oxygenated bottom water due to the fresh-
697 water runoff. The carbonates are well developed during maximum marine
698 transgression (Late TST and MFS; TST of HFS5 of MCS1 and MCS2) in well-
699 oxygenated inner-platform setting.

700 This depositional sequence model suggested here has some sort of
701 agreement with a new sequence stratigraphic model proposed by Horbury
702 (2018) for Triassic to Middle Jurassic of the NW Arabian Platform. Horbury's
703 (2018) model is designed for restricted inner-platform depositional system,
704 unlike the classical carbonate sequence stratigraphic models (Sarg, 1988;
705 Sarg et al., 1999) that were dedicated for open marine and shelf-margin
706 condition. Horbury (2018) placed fluvial deposits and restricted lithofacies
707 (e.g., interbedded anhydrite and dolomite, marginal marine shale) in lowstand
708 system tracts (LST) and early transgressive systems tract (early TST),
709 whereas higher-energy carbonates and deep-water shale are well developed
710 later in TST and MFS. A prograding clinoforms with open-marine conditions
711 were placed in highstand systems tract (HST). These late-TST high-energy
712 carbonate and the highstand prograding clinoforms can be observed in Kuwait
713 (Al-Eidan et al., 2009) and probably in Abu Dhabi (Al-Sharhan et al., 2014),
714 but not in the Marrat outcrop as it is considered a restricted inner-platform
715 setting. This implies that the Arabian Platform is a unique extensive shelf that
716 has no analog counterpart whether modern or ancient.

717 7.2 Controlling factors of the Toarcian Marrat Formation

718 7.2.1 Tectonics and subsidence

719 The Marrat Formation records an overall relative sea-level rise after the
720 tectonic related Triassic–Jurassic unconformity, which is in agreement with a
721 global eustatic rise during this period (Haq, 2018). Differential subsidence of
722 the Arabian Platform at this location promoted the onlapping geometries on
723 the underlying Minjur unconformity (Kuwait and Oman; Clarke, 1988; Yousif
724 and Nouman, 1997; Stewart et al., 2016). The effect of the subsidence is very
725 clearly demonstrated along the transect by the complete wedging and onlap
726 of the succession from north to the south. The maximum accumulation rate of
727 the Marrat Formation, calculated by dividing the total thickness of the
728 formation by the 3.5 Myr duration of the *serpentinum* Zone and *bifrons* Zone
729 (Gradstein et al., 2012) is 3.9 cm/kyr (Khashm Ad Dhibi). This falls within the
730 lower range of passive margins accumulation rate (few centimeters to 10
731 cm/kyr; Bott, 1992). The low accumulation rates of the non-marine and
732 coastal-plain siliciclastic sections are below this range (e.g., Khashm Khalta
733 1.83 cm/kyr, W. Birk 1.2 cm/kyr, K. Abu Al Jiwar 0.13 cm/kyr). Most of the
734 time, these wedging geometries and the northwards increase of subsidence
735 are very progressive all along the transect with an average of 35 m/100 km.
736 However, at the beginning of the Marrat transgression (MCS1), the
737 subsidence rate becomes rapidly higher between Faridat Balum and Wadi Al
738 Jufayr (65 m/100 km). This suggests a local tectonic control of the subsidence
739 in this area, which could have favored the initiation of the Toarcian onlap in
740 this domain.

741 The Ar Rayn Terrane (approximately between 24° N to 25° 20′ N) was a
742 tectonically active structure and played a significant role in the basin
743 configuration of the study area. The Ar Rayn Terrane during the late Triassic
744 was probably uplifted and was eroded (Le Nindre et al., 2003). During the
745 Jurassic, the Ar Rayn Terrane subsided rapidly, which probably caused the
746 depocenter axis of the Early and Middle Jurassic outcrop (cf. Fig. 72 of
747 Manivit et al., 1990; Fig. 3 of Fischer et al., 2001). The lack of real
748 unconformity (i.e., toplap/onlap geometries) along the Early-Middle Jurassic
749 unconformity, which correspond to a very long period (late Toarcian-Aalenian)
750 attests very high stability of this domain during the Jurassic long-term
751 transgression.

752 **7.2.2 Eustatic controls**

753 In our study, the main MFS of the whole Marrat succession is within the
754 middle Toarcian (bifrons Zone) shown by the maximum landward extension of
755 the Upper Marrat carbonate unit. This is in concordance with the Arabian
756 Plate MFS J10 (Fig. 14; Sharland et al., 2001), which coincides with a positive
757 d¹³C peak interpreted by Al-Mojel et al. (2018) as a sign of important marine
758 productivity levels favored by a high sea-level. Consistently, the bifrons Zone
759 marks the interval of the highest global sea-level rise during the Early Jurassic
760 (Haq et al., 1988, Haq, 2018) and the major MFS of the NW Tethys in the
761 European domain (Hardenbol et al., 1998) and drowning event in the
762 Mediterranean domain (Jenkyns et al., 1985; Crevello, 1990). Subordinate
763 MFS (MFS J09) have to be placed in the early Toarcian (serpentinum Zone)
764 in the highly bioturbated carbonate interval of the Lower Marrat unit. Caution
765 should be used if attempting to relate normal-marine depositions and/or high
766 faunal diversity interval as a main eustatic MFS without seeing the
767 geometrical stacking patterns. In such mixed carbonate-siliciclastic platform,
768 true MFS is difficult to recognize without a regional context (Davies et al.,
769 2002). During certain marine transgression, outer-platform with normal-marine
770 depositional condition can jump in inner-platform setting especially after
771 environmental related carbonate decline (Hunt and Tucker, 1993). Thus,
772 having a highly bioturbated carbonate interval with maximum faunal diversity
773 in the first marine transgression event (Serpentinum Zone) could be a
774 consequence of the major early Toarcian extinction (Fig. 15) and not just a
775 result of maximum eustatic rise. The biodiversity can also be controlled by the
776 physiography of the carbonate platform (e.g., width, inclination, occurrence of
777 a barrier) which is not the same (at least the width) between MCS1 and MCS2
778 with the ongoing transgression and onlap of the Jurassic deposits on the
779 Arabian Platform. Paleocological conditions are so complex that it is
780 dangerous to use biodiversity as the main indicator for MFS hierarchy.

781 The top sequence boundary of the Marrat sequences corresponds to a
782 regional hiatus over the Arabian Platform, in the late Toarcian–Aalenian, that
783 relates to a substantial eustatic sea-level fall (Le Nindre et al., 1990; Al-
784 Husseini, 1997; Jacquin et al., 1998; Simmons et al., 2007; Ogg and Hinnov,
785 2012; Haq and Al-Qahtani, 2005; Haq, 2018; Simmon and Davies, 2018)
786 and/or subsidence resistance and large-scale uplift (Le Nindre et al., 2003; Al-
787 Mojel et al., 2018) or relative sea-level stillstand with infill of accommodation
788 space by the sediments. The lack of any incision during this long-term hiatus
789 suggests that there is no major high amplitude sea-level fall during this period.
790 This hiatus is widespread in the Tethyan domain which is possibly related to
791 thermal basaltic doming in the North Sea with volcanic activities associated
792 with subsequent collapse (Hallam, 2001). In detail, these two composite
793 sequences MCS1 and MCS2 could correspond to the Tethyan eustatic
794 sequences Toa3 and Toa4 of Hardenbol et al. (1998), which considered as
795 3rd-order cycle of ~1.6 Myr influenced by astronomical forcing controls,
796 precession and obliquity including their long-term modulations (Hinnov and
797 Park, 1999; Boulila et al., 2014).

798 The short-term fluctuation of relative sea-level changes recorded on the
799 Arabian Platform during deposition time of the Marrat Formation range from
800 15 to 25 m (calculated from relative sea-level amplitude of Haq and Al-
801 Qahtani, 2005). This gives an average rate of 0.08 m/kyr, which correspond to
802 a moderate amplitude of relative sea-level changes (>15 m; Read, 1995,
803 1998). Whereas the cause of such moderate sea-level changes in warm
804 greenhouse periods is still debated. It is most likely related to aquifer-eustasy
805 (Wendler et al., 2016; Sames et al., 2016). An alternative scenario for the
806 origin of this moderate amplitude of relative sea-level is the onset opening and
807 sea floor spreading of the Atlantic Ocean (Hallam, 2001).

808 **7.2.3 Climatic influences**

809 During the Early Jurassic, the Arabian Platform was situated along the
810 tropical belt probably a few degrees south of the Equator (Fig. 2; Murris, 1980;
811 Thierry et al., 2000; Sharland et al., 2001) Here, the study of the Toarcian
812 sediments from the Marrat Formation allow us to address for the first time the
813 impact of these climatic disturbances in a coastal/inner-platform context
814 situated at very low paleolatitudes. Among the Jurassic climate changes
815 (Dera et al., 2011), the early Toarcian warming event is generally considered
816 as the warmest interval, as current numerical models suggest rapid
817 temperature rises of +5 to +10°C in terrestrial domains (Dera and Donnadieu,
818 2012). This episode was also documented in marine paleoenvironments from
819 European domains with shifts in the oxygen isotope composition of various
820 fossils (Bailey et al., 2003, van de Schootbrugge et al., 2005; Suan et al.,
821 2010). Probably initiated by considerable CO₂ releases from Karoo-Ferrar
822 volcanism and subsequent clathrate destabilization on the seafloor (Hesselbo
823 et al., 2000), this disturbance is further believed to have caused a
824 redistribution of humid belts toward mid- and high-latitudes (Dera et al., 2015),
825 and global increases of weathering rates (Cohen et al., 2004, Dera et al.,
826 2009). Occurrence of fluvial systems during the Lower Marrat transgression
827 (MCS1) with plant fragments, high kaolinite (Abed, 1979) and high gamma-ray
828 response (Fig. 13) suggest humid period which corresponded to the initial
829 warm peak of the early *serpentinum* Zone (Fig. 15). The humid period evolved
830 to more semi-arid condition during late TST and MFS of MCS1 evident by
831 stromatolites, mudcracks with limited siliciclastic influx and later with
832 carbonate development. The semi-arid condition and the carbonate
833 development could be related to slight decrease of the paleotemperature
834 during late *serpentinum* Zone (Fig. 15; Gomez and Goy, 2011). The
835 regressive evolution recorded in the Middle Marrat (turn-over between MSC1
836 and MSC2) with the deposition of thick and extensive kaolinite and hematite
837 enrichments of reddish shale (Abed, 1979) and sandstone deposits cannot be
838 considered as a response to the decrease of accommodation rate but to an
839 increase of the terrigenous influx. This shale-dominated influx could be
840 interpreted as indicative of strong hydrolyzing conditions under humid and
841 warm conditions (Chamley, 1989). These observations are thus compatible
842 with numerical simulation suggesting rises in precipitation and runoff rates (+5
843 to 15 cm/kyr) on the southern part of the Arabian craton (Dera and
844 Donnadieu, 2012). The Middle Marrat could be really the best record of an
845 increase of humidity during the early Toarcian warm period (Fig. 15). In the
same way, the MCS2 transgression could be favored by a combination of eustatic transgression (*bifrons* Zone) and decrease of the siliciclastic input indicating more semi-arid conditions with possible simultaneous overall decrease in paleotemperature during the *bifrons* Zone (Fig. 15). Remarkably, the synchronicity of the TST and MFS with semi-arid and cooling events and HST with humid warm condition provides some confidence to the aquifer-eustasy as primary mechanism controlling these 3rd-order sea-level changes (cf. Wendler et al., 2016; Sames et al., 2016).

## 8 Conclusion

The outcrops of the Marrat Formation (early to middle Toarcian) in Saudi Arabia provide a stratigraphic record of the initial Jurassic transgression of a broad slowly subsiding epeiric tropical platform over the Triassic–Jurassic unconformity. The depositional environment ranges from continental meandering fluvial deposits to tidal or wave-dominated mixed carbonate-siliciclastic inner-platform deposits. These formed aggraded flat-topped platform wedging and thickening northward. Syndepositional differential subsidence has an influence on lateral thickness variation and facies distribution. The carbonates are mud-dominated facies and are preferentially formed in high subsidence areas with more accommodation space. The Marrat Formation is composed of two 3rd-order sequences and show progressive marine transgression that reach its maximum in the middle Toarcian *bifrons* Zone, consistent with the major MFS of the Early Jurassic of the Arabian Platform and the European major MFS. The layer-cake geometries are controlled by the low-energy wide platform with stable tectonic context, that leads for limited accommodation space filled by siliciclastic
871 supply and carbonate production. Short-lived higher energy siliciclastic
872 shorelines and tidal-flat appear during high accommodation space in late-TST
873 and HST. The carbonates are best developed during maximum marine
874 transgression of the two Marrat sequences. High terrigenous influx event
875 between these two sequences consists of aggraded extensive continental red
876 shales and fluvial sandstone. This is possibly related to the strong hydrolyzing
877 conditions under humid-warm period (early-middle Toarcian *bifrons* Zone
878 rather than a decrease of accommodation space. The synchronicity of the
879 regression with humid-warm periods provides some confidence to the aquifer-
880 eustasy driver mechanism of the Marrat depositional sequences.

881 Acknowledgments

882 This work was part of a PhD thesis that was carried out at the University of
883 Bordeaux-Montaigne, ENSEGID Bordeaux INP, and was sponsored by Saudi
884 Aramco. We thank the management of Saudi Aramco for the permission to
885 publish this work. We express our thankfulness and gratitude to Dr. Aus Al-
886 Tawil (RCD manager, Saudi Aramco) for his endless outstanding support and
887 motivations during all phases of this study. We also thank Dr. Denis Vaslet,
888 Prof. J. Fred Read, Prof. Charles Kerans, Dr. Moujahed Al-Husseini and Dr.
889 Langhorne Smith for providing valuable suggestions and constructive
890 comments. Special thanks to Dr. Mohammed Al-Masrahy for significantly
891 improving the article. We also extend our thanks to Dr. Mahmoud Al-Nazghah
892 and Dr. Raed Al-Dukhayyil for field support.
893 **References**

894 Abdullah, F.H., Connan, J., 2002. Geochemical study of some Cretaceous
895 rocks from Kuwait: comparison with oils from Cretaceous and Jurassic
896 reservoirs. Organic geochemistry, 33(2), 125-148.

897 Abed, A.M., 1979. Lower Jurassic lateritic redbeds from central
898 Arabia. Sedimentary Geology 24 (1), 149-156.

899 Al-Eidan, A., Neog, N., Narhari, S., Al-Darmi, A., Al-Mayyas, R., De Keyser,
900 T., Perrin, C., 2009. Depositional Environments of the Marrat Formation
901 (Lower Jurassic), North Kuwait. Search and Discovery Article, 50223, 7-
902 10.

903 Al-Husseini, M.I., 1997. Jurassic sequence stratigraphy of the western and
904 southern Arabian Gulf. GeoArabia (Manama), 2(4), 361-82.

905 Al-Husseini, M.I., 2000. Origin of the Arabian plate structures: Amar collision
906 and Najd Rift. GeoArabia 5, 527-542.

907 Al-Husseini, M.I., 2009. Update to Late Triassic-Jurassic stratigraphy of Saudi
908 Arabia for the Middle East geologic time scale. GeoArabia 14(2), 145-186.

909 Al-Husseini, M.I., Matthews, R.K. 2008. Jurassic-Cretaceous Arabian orbital
910 stratigraphy: The AROSJK Chart, GeoArabia, 13 (1), 89-94.

911 Al-Masrahy M.A., Mountney N.P., 2015. Quantitative approach to the
912 characterization of sedimentary architecture in mixed eolian-fluvial
913 reservoir successions, Search and Discovery Article 41669. 1-4.

914 Al-Mojel, A., 2017. Sedimentology and sequence stratigraphy of the Jurassic,
915 Jebal Tuwaiq, Central Saudi Arabia. Ph.D. Thesis, Univ. Bordeaux 3,
916 Bordeaux, France.

917 Al-Mojel, A., Dera, G., Razin, P., Le Nindre, Y.M., 2018. Carbon and oxygen
918 isotope stratigraphy of Jurassic platform carbonates from Saudi Arabia:
919 Implications for diagenesis, correlations and global paleoenvironmental
920 changes. Palaeogeography, Palaeoclimatology, Palaeoecology. In press.

921 Al-Sharhan, A.S., Strohmenger, C.J., Al-Mansoori, A.A., 2014. Mesozoic
922 petroleum systems of Abu Dhabi, United Arab Emirates. In: Marlow, L.,
923 Kendall, C., Yose, L., (Eds.), Petroleum systems of the Tethyan region:
924 AAGP Memoir 106, 679-711.

925 Allen, J.R.L., 1982. sedimentary structures: their character and physical basis,
926 Volume 1. Elsevier, Amsterdam. 611.

927 Alsharhan, A.S., Nairn, A.E.M., 1994. The Late Permian carbonates (Khuff
928 Formation) in the western Arabian Gulf: Its hydrocarbon parameters and
929 paleogeographical aspects. Carbonates and Evaporites, 9(2), 132.

930 Alsharhan, A.S., Nairn, A.E.M., 2003. Sedimentary basins and petroleum
931 geology of the Middle East. Elsevier, Amsterdam, 843 pp.

932 Aqrawi, A., Goff, J.C., Horbury, A., Sadooni, D., 2010. The petroleum Geology
933 of Iraq. Beaconsfield, UK, Scientific Press, 424.

934 Ayres, M.G., Bilal, M., Jones, R.W., Slentz, L.W., Tartir, M., Wilson, A.O.,
935 1982. Hydrocarbon habitat in main producing areas, Saudi Arabia. AAPG
936 bulletin, 66(1), 1-9.

937 Bailey, T.R., Rosenthal, Y., McArthur, J.M., Van de Schootbrugge, B.,
938 Thirwall, M.F., 2003. Paleceanographic changes of the Late
939 Pliensbachian-Early Toarcian interval: a possible link to the genesis of an
940 Oceanic Anoxic Event. Earth and Planetary Science Letters, 212, 307–

941 320.

942 Banerjee, I. 1991. Tidal sand sheets of the Late Albian Joli Fou-Kiowa-Skull

943 Creek Marine transgression, Western Interior Seaway of North America.

944 335-347.

945 Banham, S.P., Mountney, N.P. 2014, Climatic versus halokinetic control on

946 sedimentation in a dry land fluvial succession. Sedimentology 61, 570–

947 608.

948 Baud, A., Droste, H., Guillocheau, F., Razin, P., Robin, C., 2005. Mesozoic

949 Evolution of the Tethyan margin of Oman. In 24th IAS regional Meeting,

950 Pre-Conference Excursion BF. 4.

951 Baudin, F., Herbin, J.P., Bassoullet, J.P., Dercourt, J., Lachkar, G., Manivit,

952 H., Renard, M., 1990. Distribution of organic matter during the Toarcian in

953 the Mediterranean Tethys and Middle East. In Deposition of organic

954 facies, The American Association of Petroleum Geologists, 30, 73-91.

955 Blum, M.D., Törnqvist, T.E., 2000. Fluvial responses to climate and sea-level

956 change: a review and look forward. Sedimentology, 47, 2-48.

957 Bott, M.H.P., 1992. Passive margins and their subsidence. Journal of the

958 Geological Society, 149(5), 805-812.

959 Bottjer, D.J., Arthur, M.A., Dean, W.E., Hattin, D.E., Savrda, C.E., 1986.

960 Rhythmic bedding produced in Cretaceous pelagic carbonate

961 environments; sensitive recorders of climatic cycles. Paleooceanography,

962 1(4), 467-481

963 Boulila, S., Galbrun, B., Huret, E., Hinnov, L. A., Rouget, I., Gardin, S.,

964 Bartolini, A., 2014. Astronomical calibration of the Toarcian Stage:

965 implications for sequence stratigraphy and duration of the early Toarcian

966 OAE. Earth and Planetary Science Letters, 386, 98-111.

967 Bramkamp, R.A., Steineke, M., 1952. Stratigraphical introduction. In: Arkell,

968 W.J., Bramkamp, R.A., Steineke, M. (Eds.), Jurassic Ammonites from

969 Jebel Tuwaiq, Central Arabia. Royal Society [London] Philosophical

970 Transactions B 236, 241–313.

971 Bridge, J.S., 2006. Fluvial facies models: recent developments. In: H.W.,

972 Walker, R.G., (Ed.), Facies models revisited. International Association of

973 Sedimentologists, Special Publication 84, 85-170.

974 Bromley, R.G., Ekdale, A.A., 1984. Trace fossil preservation in flint in the

975 European chalk. Journal of Paleontology, 58, 298–311.

976 Chamley, H., 1989. Clay Sedimentology. Springer Verlag, Berlin.

977 Church, M. 2006. Bed material transport and the morphology of alluvial river

978 channels. The Annual Review of Earth and Planetary Science, 34, 325–

979 354.

980 Clarke, M.W.H., 1988. Stratigraphy and rock unit nomenclature in the oil-

981 producing area of interior Oman. Journal of Petroleum Geology, 11(1), 5–

982 60.

983 Cohen, A.S., Coe, A.L., Harding, S.M., Schwark, L., 2004. Osmium isotope

984 evidence for the regulation of atmospheric CO2 by continental

985 weathering. Geology 32 (2), 157–160.

986 Collinson, J.D., 1996. Alluvial sediments. In: Reading, H.G. (Ed.),

987 Sedimentary Environments: Processes, Facies and Stratigraphy,

988 Blackwell Science, 37-82.
989 Crevello, P. D., 1990, Depositional systems tracts, stacking patterns, and
sequence stratigraphy of Lower and Middle Jurassic synrift carbonate
990 platforms, Central and Eastern High Atlas, Morocco. International
991 Association of Sedimentologists, 1990 Annual Meeting, Proceedings with
992 Abstracts, 111-112.
993

994 Davies, R.B., Casey, D.M., Horbury, A.D., Sharland, P.R., Simmons, M.D., 2002. Early to mid-Cretaceous mixed carbonate-clastic shelfal systems: Examples, issues, and models from the Arabian Plate. GeoArabia 7, 541-598.
995
996
997

998 Davis Jr, R.A., 2012. Tidal signatures and their preservation potential in
999 stratigraphic sequences. In: Davis Jr. R.A., Dalrymple, R.W. (Eds.),
1000 Principles of tidal sedimentology. Springer, Netherlands, 35-55.

1001 Delvaux, D., 2001. Karoo rifting in western Tanzania: Precursor of Gondwana
1002 breakup. Contributions to geology and paleontology of Gondwana in
1003 honor of Helmut Wopfner: Cologne, Geological Institute, University of
1004 Cologne, 111-125.

1005 Dera, G., Brigaud, B., Monna, F., Laffond, R., Puceat, E., Deconinck, J.F.,
1006 Pellenard, P., Joachimsky, M., Durlet, C., 2011. Climatic ups and downs
1007 in a disturbed Jurassic world. Geology 39, 215-218.

1008 Dera, G., Donnadieu, Y., 2012. Modeling evidences for global warming, Arctic
1009 seawater freshening, and sluggish oceanic circulation during the Early
1010 Toarcian anoxic event. Paleoceanography, 27(2).

1011 Dera, G., Pellenard, P., Neige, P., Deconinck, J. F., Pucéat, E., Dommergues, J. L. 2009. Distribution of clay minerals in Early Jurassic Peritethyan seas: palaeoclimatic significance inferred from multiproxy comparisons. Palaeogeography, Palaeoclimatology, Palaeoecology, 271(1), 39-51.

1016 Dera, G., Prunier, J., Smith, P. L., Haggart, J. W., Popov, E., Guzhov, A.,
1017 Rogov, M., Delsate, D., Thies, D., Cuny, G., Pucéat, E., Charbonnier, D.,
1018 Bayon, G., 2015. Nd isotope constraints on ocean circulation,
1019 paleoclimate, and continental drainage during the Jurassic breakup of
1020 Pangea. Gondwana Research, 27(4), 1599-1615.

1021 Dumas, S., Arnott, R.W.C., 2006. Origin of hummocky and swaley cross-stratification–The controlling influence of unidirectional current strength and aggradation rate. Geology, 34(12), 1073-1076.

1024 Dunham, R.J., 1962. Classification of carbonate rocks according to depositional texture. In: Ham, W.E. (Ed.), Classification of Carbonate Rocks: AAPG Memoir 1, 108-121. Tulsa, OK.

1027 Embry, A.F., 1995. Sequence boundaries and sequence hierarchies: problems and proposals. In: Steel, R.J., Felt, V.L., Johannessen, E.P., Mathieu, C. (Eds.), Sequence stratigraphy on the Northwest European Margin. Special Publication, vol. 5. Norwegian Petroleum Society, pp. 1-11.

1032 Embry, A.F., Klovan, J.E., 1971. A late Devonian reef tract on northeastern
1033 Banks Island, NWT. Bulletin of Canadian Petroleum Geology, 19(4), 730-
1034 781.

1035 Énay, R., Y.-M. Le Nindre, C. Mangold, J. Manivit and D. Vaslet 1986. The
1036 Jurassic of central Saudi Arabia: New data on lithostratigraphic units,
1037 palaeoenvironments, ammonite faunas, ages and correlations. Deputy
1038 Ministry of Mineral Resources, Jiddah, Technical Record BRGM-TRO6-3,
1039 65 p.

1040 Énay, R., Y.M. Le Nindre, C. Mangold, J. Manivit and D. Vaslet 1987. Le
1041 Jurassique d'Arabie Saoudite centrale: nouvelles données sur la
1042 lithostratigraphie, les paléoenvironnements, les faunes d'ammonites, les
1043 âges et les corrélations. Geobios, Lyon, Special Memoir 9, p. 13-65.

1044 Fischer, J.-C., Manivit, J., Vaslet, D., 2001. Jurassic gastropod faunas of
1045 central Saudi Arabia. GeoArabia (Manama), 6(1), 63–100.

1046 Fisher, J.A., Krapf, C.B.E., Lang, S.C., Nichols, G.J. and Payenberg, T.H.D.,
1047 2008. Sedimentology and architecture of the Douglas Creek terminal
1048 splay, Lake Eyre, central Australia. Sedimentology 55, 1915-1930

1049 Frey, R. W. (ed.). 1975. The study of trace fossils: a synthesis of principles,
1050 problems, and procedures in ichnology. New York, Springer-Verlag.

1051 Friend, P.F., Slater, M.J., Williams, R.C., 1979. Vertical and lateral building of
1052 river sandstone bodies, Ebro Basin, Spain. Geological Society of
1053 London136, 39-46.

1054 Galli, G., 1993. "Calcari Grigi" formation, Jurassic, Venetian Alps. In: Galli, G.
1055 (Ed.), Temporal and Spatial Patterns in Carbonate Platforms. Springer,
1056 Berlin, 97-129.

1057 Gerard, J., Bromley, R., 2008. Ichnofabrics in clastic sediments: applications
to sedimentological core studies (p. 100). Madrid: J. Gerard.

1059 Gibleing, M.R., 2006. Width and thickness of fluvial channel bodies and valley
1060 fills in the geological record: A literature compilation and classification.
1061 Journal of Sedimentary Research 76, 731-770.

1062 Ginsburg, R. N., 1975. Tidal deposits: a casebook of recent examples and
fossil counterparts. Springer Science & Business Media.

1064 Glennie, K.W., Boeuf, M.G.A., Hughes-Clarke, M.W., Moody-Stuart, M., Pilaar
1065 W., Reinhardt, B.M., 1995. Late Cretaceous nappes in Oman Mountains
1066 and their geological evolution. AAPG Bulletin, 57, 5-27.

1067 Gómez, J.J., Goy, A., 2011. Warming-driven mass extinction in the Early
1068 Toarcian (Early Jurassic) of northern and central Spain. Correlation with
1069 other time-equivalent European sections. Palaeogeography,
1070 Palaeoclimatology, Palaeoecology, 306(3), 176-195.

1071 Gradstein, F.M., Ogg, J.G., Schmitz, M.D., Ogg, G.M., 2012. The Geologic
Time Scale 2012. Elsevier, p. 1144.

1073 Hallam, A., 2001. A review of the broad pattern of Jurassic sea-level changes
1074 and their possible causes in the light of current
1075 knowledge. Palaeogeography, Palaeoclimatology, Palaeoecology, 167(1),
1076 23-37.

1077 Haq, B.U., 2018. Jurassic sea-level variations: a reappraisal. GSA
Today, 28(1).

1079 Haq, B.U., Al-Qahtani, A.M., 2005. Phanerozoic cycles of sea-level change on
the Arabian Platform. GeoArabia, 10(2), 127-160.

1081 Haq, B.U., Hardenbol, J., Vail, P.R., 1987. Chronology of fluctuating sea
levels since the Triassic. Science, 235 (4793), 1156-1167.

1083 Haq, B.U., Hardenbol, J., Vail, P.R., 1988. Mesozoic and Cenozoic
1084 chronostratigraphy and cycles of sea-level change. SEPM Special
1085 Publications 42, 71-108.

1086 Hardenbol, J., Jacquin, T., Farley, M.B., de Graciansky, P.C., Vail, P.R., 1998.
1087 Mesozoic and Cenozoic sequence chronostratigraphic framework of
1088 European basins. In: de Graciansky, P. C., Hardenbol, J., Jaquin, T., Vail, P.R. (Eds.), Mesozoic and Cenozoic Sequence Stratigraphy of European Basins. Society for Sedimentary Geology (SEPM), Tulsa, 3-13.

1091 Harms, J.C., Southard, J.B., Spearing, D. R., Walker, R. G., 1975, Depositional environments as interpreted from primary sedimentary structures and stratification sequences: SEPM Short Course No. 2, 161 p.

1094 Hatano, N., Yoshida, K., 2017. Sedimentary environment and paleosols of middle Miocene fluvial and lacustrine sediments in central Japan: Implications for paleoclimate interpretations. Sedimentary geology, 347, 117-129.

1098 Hesselbo, S.P., Gröcke, D.R., Jenkyns, H.C., Bjerrum, C.J., Farrimond, P., Morgans Bell, H.S., Green, O.R., 2000. Massive dissociation of gas hydrate during a Jurassic oceanic anoxic event. Nature 406, 392-395.

1101 Hinnov, L. A., Park, J. J., 1999. Strategies for assessing Early-Middle (Pliensbachian-Aalenian) Jurassic cyclochronologies. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 357(1757), 1831-1859.

1105 Horbury, A., 2018. Petroleum geology and its relation to stratigraphic architecture of the Triassic to Middle Jurassic (Induan to Aalenian) Interval on the Arabian Plate. In: Pöppelreiter, M.C. (Ed.), Lower Triassic to Middle Jurassic Sequence of the Arabian Plate. EAGE, 49-100.

1109 Hunt, D., Tucker, M.E., 1993. Sequence stratigraphy of carbonate shelves with an example from the mid-Cretaceous (Urgonian) of southeast France. Sequence stratigraphy and facies associations, 307-341.

1112 Issautier, B., Le Nindre, Y. M., Abdullah, M., Saleh, D., Sophie, V., 2012. Managing clastic reservoir heterogeneity I: sedimentology and sequence stratigraphy of the Minjur Sandstone at the Khashm-al-Khalta type locality (Central Saudi Arabia). GeoArabia, 17(2), 17-56.

1116 Issautier, B., Le Nindre, Y., Memesh, A., Dini S., Viseur, S., 2012a. Managing clastic reservoir heterogeneity, I: Sedimentology and sequence stratigraphy of the Late Triassic Minjur Sandstone at the Khashm al Khalta type locality Central Saudi Arabia. GeoArabia 17(2), 17-56.

1120 Issautier, B., Le Nindre, Y., Viseur S., Memesh, A., Dini, S., 2012b. Managing clastic reservoir heterogeneity, II: Geological modelling and reservoir characterization of the Minjur Sandstone at the Khashm Al Khalta type locality, Central Saudi Arabia. GeoArabia 17(3), 61-80.

1124 Jacquin, T., Dardeau, G., Durlet, C., de Graciansky, P.C., Hantzpergue, P., 1998. The North Sea cycle: an overview of 2^nd^-order transgressive/regressive facies cycles in western Europe. In: de Graciansky, P-C., Hardenbol, J., Jacquin, T., Vail, P.R. (Eds.), Mesozoic an overview of 2^nd^ order transgressive/regressive facies cycles in Western Europe. SEPM, Special Publication (60), 397-410.

1130 Jenkyns, H.C., Sarti, M., Masetti, D., and Howarth, M.K., 1985, Ammonites and stratigraphy of Lower Jurassic black shales and pelagic limestones from the Belluno trough, southern Alps: Ecologae Geologicae Helvetiae, 78, 299-311.

1134 Kadar, A.P., De Keyser, T., Neog, N., Karam, K.A., Le Nindre Y.M., Davies, R.B., 2015. Calcareous nannofossil zonation and sequence stratigraphy of the Jurassic System, onshore Kuwait. GeoArabia, 20(4), 125-180.
1137 Kerans, C., Tinker, S.W., 1997. Sequence stratigraphy and characterization of carbonate reservoirs. Society of Sedimentary Geology: SEPM Short Course Notes, 40.

1138 Khalifa, M.A., 2007. Triassic-Jurassic boundary on the southern margin of Tethys: implications of facies, tectonics and volcanism. In: Lucas, S.G., Spielmann, J.A. (Eds.), The Global Triassic. New Mexico Museum of Natural History and Science, Bulletin 41, 110-119.

1140 Khetani, A.B., Read, J.F., 2002. Sequence development of a mixed carbonate-siliciclastic high-relief ramp, Mississippian, Kentucky, USA. Journal of Sedimentary Research, 72(5), 657-672.

1141 Kraus, M. J., 1999. Paleosols in clastic sedimentary rocks: their geologic applications. Earth-Science Reviews, 47(1-2), 41-70.

1142 Le Métour, J., Rabu, D., Tegyey, M., Béchennec, F., Beurrier, M., Villey, M., 1990. Subduction and obduction: two stages in the Eo-Alpine tectonometamorphic evolution of the Oman Mountains: In Robertson, A.H.F, Searle, M. P., Ries, A.C. (Eds), The Geology and Tectonics of the Oman Region: Geological Society of London, Special Publication 49, 327-340.□

1143 Le Nindre, Y.M., Manivit, J., Manivit, H., Vaslet, D., 1990. Stratigraphie sequentielle du Jurassique et du Cretace en Arabie Saoudite. Bulletin Société Géologique France, Paris 6, 1025-1035.

1144 Le Nindre, Y.M., Vaslet, D., Le Métour, J., Bertrand, J., Halawani, M., 2003. Subsidence modelling of the Arabian Platform from Permian to Paleogene outcrops. Sedimentary Geology, 156, 263-285.

1145 Leckie, D.A., Walker, R.G., 1982. Storm-and tide-dominated shorelines in Cretaceous Moosebar-Lower Gates interval--outcrop equivalents of Deep Basin gas trap in western Canada. AAPG Bulletin, 66(2), 138-157.

1146 Leckie, D.A., Walker, R.G., 1982. Storm-and tide-dominated shorelines in Cretaceous Moosebar-Lower Gates interval--outcrop equivalents of Deep Basin gas trap in western Canada. AAPG Bulletin, 66(2), 138-157.

1147 Lukasik, J.J., James, N.P., McGowran, B., Bone, Y., 2000. An epeiric ramp: low-energy, cool-water carbonate facies in a Tertiary inland sea, Murray Basin, South Australia. Sedimentology, 47(4), 851-881.

1148 Manivit J, Le Nindre Y.M., Vaslet D. (1990) Le Jurassique d'Arabie Centrale. In Histoire Gologique de la Bordure Occidentale de la Plate-forme Arabe. Volume 4. Document du BRGM n°194.

1149 Manivit, J., Pellaton, C., Vaslet, D., Le Nindre, Y.M., Brosse, J.M., Fourniguet, J., 1985a. Geologic map of the Wadi al Mulayh quadrangle, sheet 22H, Kingdom of Saudi Arabia. Saudi Arabian Deputy Ministry for Mineral Resources Geosciences Map, GM-92, scale, 1(250,000), 1-32.

1150 Manivit, J., Pellaton, C., Vaslet, D., Le Nindre, Y.M., Brosse, J.M., Breton, J.P., Fourniguet, J., 1985b. Geologic map of the Darma quadrangle, sheet 24H, Kingdom of Saudi Arabia. Saudi Arabian Deputy Ministry for Mineral Resources Geosciences Map, GM-101, scale, 1(250,000), 133.

1151 McIlroy, D., 2004. Ichnofabrics and sedimentary facies of a tide-dominated delta: Jurassic Ile Formation of Kristin Field, Haltenbanken, offshore Mid-Norway. Geological Society, London, Special Publications, 228(1), 237-272.

1152 McKee, E. D., 1966. Significance of climbing-ripple structure. US Geol. Surv. Prof. Papper, 550, 94-103.
1187 McKee, E.D., 1966. Structures of dunes at White Sands National Monument, New Mexico (and a comparison with structures of dunes from other selected areas). Sedimentology 7, 1-69.

1188
1189
1190 Miall, A. D., 1996, The geology of fluvial deposits: sedimentary facies, basin analysis and petroleum geology: Springer-Verlag Inc., Heidelberg, 582p.

1191 Miall, A.D., 1977. A review of the braided river depositional environment. Earth Science Reviews 13, 1-32.

1192 Miall, A.D., 1978. Fluvial sedimentology. Canadian Society Petroleum Geologists, Memoir 5,105-127.

1193 Miller, W., 2007. Complex trace fossils. In Trace Fossils (pp. 458-465).

1194 Murris, R.J., 1980. Middle East: Stratigraphic evolution and oil habitat. AAPG Bulletin, 64,597-618.

1195 Ogg, J.G., Hinnov, L.A., 2012. Jurassic. In: Gradstein, F.M., Ogg, J.G., Schmitz, M., Ogg, G. (Eds.), The Geologic Time Scale 2012, 1st Edition (1), 731-791.

1200
1201
1202 Olsen, H., Due, P.H., Clemmensen, L.B., 1989. Morphology and genesis of asymmetric adhesion warts- a new adhesion surface structure: Sedimentary Geology 61, 277-285.

1205 Osman, M., Abdullatif, O., Bashri, M., Babikr, J., 2018. Geological outcrop modelling of the Minjur and Marrat Formations – Integration of sedimentology and LiDAR data, Central Saudi Arabia. In: Pöppelreiter, M.C. (Ed.), Lower Triassic to Middle Jurassic Sequence of the Arabian Plate. EAGE, 229-248.

1210 Pöppelreiter, M., Sharp, R., Turner, M., Haggas, S., Lewis, S., 2018. Overview of the global geological setting and the exploration and development history of the lower Triassic to Middle Jurassic. In: Pöppelreiter, M.C. (Ed.), Lower Triassic to Middle Jurassic Sequence of the Arabian Plate. EAGE, 33-48.

1215 Powers, R.W., 1968. Lexique Stratigraphique International, v.III, Asie, 10bl, Saudi Arabia. Centre National de la Recherche Scientifique, Paris, 177p.

1217 Powers, R.W., Ramirez, L.F., Redmond, C.D., Elberg, E.L., 1966. Geology of the Arabian Peninsula, Geological Survey Professional Paper, 560-D, 147p.

1220 Rabalais, N.N., Turner, R.E., Wiseman, W.J., & Boesch, D.F., 1991. A brief summary of hypoxia on the northern Gulf of Mexico continental shelf: 1985-1988. Geological Society, London, Special Publications, 58(1), 35-47.

1224 Read, J.F. 1995. Overview of carbonate platform sequences, cycle stratigraphy and reservoirs in greenhouse and icehouse worlds. In: Read, J.F., Kerans, C., Weber, L.J., Sarg, J.F., and Wright F.W. (Eds.), Milankovitch sea level changes, cycles and reservoirs on carbonate platforms in greenhouse and icehouse worlds, SEPM Short Course Notes No. 35, 1-102.

1230 Read, J.F., 1989. Controls on evolution of Cambrian-Ordovician passive margin, US Appalachians. In: Crevello, P.D., Wilson, J.L., Sarg, J.F., Read, J.F. (Eds.), Controls on Carbonate Platform and Basin Development, SEPM Special Publication, 44, 146-165.

1234 Read, J.F., 1998. Phanerozoic carbonate ramps from greenhouse, transitional and ice-house worlds: clues from field and modelling studies. Geological Society, London, Special Publications, 149(1), 107-135.
1237 Reineck, H.E., Singh, I.B., 1980. Depositional Sedimentary Environments.

1238 Springer-Verlag, Berlin, Heidelberg, New York, p. 549.

1239 Rubin, D.M., 1987. Cross-bedding, bedforms and palaeocurrents. Society of

1240 Economic Paleontologists and Mineralogists Concepts in Sedimentology

1241 and Paleontology 1, 187.

1242 Sames, B., Wagreich, M., Wendler, J.E., Haq, B.U., Conrad, C.P., Melinte-

1243 Dobrinescu, M.C., Hu, X., Wendler, I., Wolfgring, E., Yilmaz, I.Ö., Zorina,

1244 S.O. 2016. Review: short-term sea-level changes in a greenhouse

1245 world-a view from the Cretaceous. Palaeogeography, Palaeoclimatology,

1246 Palaeoecology, 441, 393-411.

1247 Sarg, J.F., 1988. Carbonate sequence stratigraphy. In sea level changes: an

1248 integrated approach. Society of Economic Paleontologists and

1249 Mineralogists Special Publication, 42, 155-181.

1250 Sharland, P.R., Archer R., Casey D.M., Davies R.B., Hall S.H., Heward A.P.,

1251 Horbury A.D., Simmons M.D., 2001. Arabian Plate Sequence

1252 Stratigraphy. GeoArabia Special Publication 2, Gulf PetroLink, Bahrain,

1253 371.

1254 Simmon, M.D., Sharland, P.R., Casey, D.M., Davies, R.B., Sutcliffe, O.E.,

1255 2007. Arabian Plate sequence stratigraphy: potential implications for

1256 global chronostratigraphy. GeoARabia (12), 101-130.

1257 Simmons, M.D., Davies, R.B., 2018. Triassic to Middle Jurassic stratigraphy

1258 of the Arabian plate: an introduction. In: Pöppelreiter, M.C. (Ed.), Lower

1259 Triassic to Middle Jurassic Sequence of the Arabian Plate. EAGE, 1-32.

1260 Soltan, R., Mountney, N.P., 2016. Interpreting complex fluvial channel and

1261 barform architecture: Carboniferous Central Pennine Province, northern

1262 England. Sedimentology, 63(1), 207-252.

1263 Stear W. M., 1985. Comparison of the bedform distribution and dynamics of

1264 modern and ancient sandy ephemeral flood deposits in the southwestern

1265 Karoo Region, South Africa. Sedimentary Geology 45, 209-230

1266 Stewart, S.A., Reid, C.T., Hooker, N.P., Kharouf, O.W., 2016. Mesozoic

1267 siliciclastic reservoirs and petroleum system in the Rub’Al-Khali basin,

1268 Saudi Arabia. AAPG Bulletin, 100(5), 819-841.

1269 Suan, G., Mattioli, E., Pittet, B., Lécuyer, C., Suchéras-Marx, B., Duarte, L.V.,

1270 Philippe, M., Reggiani, L., Martineau, F., 2010. Secular environmental

1271 precursors to Early Toarcian (Jurassic) extreme climate changes. Earth

1272 and Planetary Science Letters, 290(3), 448-458.

1273 Summerfield, M.A., 1985. Plate tectonics and landscape development on the

1274 African continent. In: Morisawa, M., Hack, J. (Eds.), Tectonic

1275 Geomorphology. Allen and Unwin, Boston, 27-51.

1276 Tang, D.Z., Lawrence, P., Gregory, A.E., Bakhiet, A.F.M., Bhullar, A.G.,

1277 Ahmed, A., Macurda, B., 2010. Stratigraphic Framework and Exploration

1278 Potential of Early Jurassic Marrat Formation, Northern Saudi Arabia

1279 (Abstract). Proceeding of the AAPG GEO Middle East Conference &

1280 Exhibition, Manama, Bahrain, March 7-10, 2010. AAPG Search and

1281 Discovery Article #90105.

1282 Tankard, A. J., Hobday, D.K., 1977. Tide-dominated back-barrier

1283 sedimentation, early Ordovician Cape Basin, Cape Peninsula, South

1284 Africa. Sedimentary Geology, 18(1-3), 135-159.

1285 Thierry, J., Barrier, E., Abbate, E., Ait-Ouali, R., Ait-Salem, H., Bouaziz, S.,

1286 Canerot, J., Elmi, S., Geluk, M., Georgiev, G., Guiraud, R., Hirsch, F.,
1287 Ivanik, M., Le Metour, J., Le Nindre, Y.M., Medina, F., Nikishin, A.M.,
1288 Page, K., Panov, D.L., Pique, A., Poisson, A., Sandulescu, M., Sapunov,
1289 I.G., Seghedi, A., Soussi, M., Tarkowski, R.A., Tchoumatchenko, P.V.,
1290 Vaslet, D., Volozh, Y.A., Voznezenski, A., Walley, C.D., Ziegler, M., Ait-
1291 Brahim, L., Bergerat, F., Bracene, R., Brunet, M.F., Cadet, J.P., Guezou,
1292 J.C., Jabaloy, A., Lepvrier, C., Rimmele, G., Belaid, A., Bonneau, M.,
1293 Boutakiout, M., Chellai, E., Coutelle, A., Fedan, B., Fekirine, B.,
1294 Guillocheau, F., Julien, M., Kokel, F., Laadila, M., Lott, G.N., Lamarche,
1295 J., Mami, L., Mansy, J.L., Mascle, G., Meister, C., Mouty, M., Pascal, C.,
1296 Robin, C., Sebrier, M., Sihamdi, N., Souhel, A., Stephenson, R., Vera,
1297 J.A., Vuks, V.J., Vrielynck, B., Olivet, J.L., 2000a. Map 8, Middle Toarcian
1298 (180-178Ma). In: Dercourt, J., et al. (Ed.), Atlas Peri-Tethys,
1299 Paleogeographical Maps. Paris.

1300 Thomas, R.G., Smith, D.G., Wood, J.M., Visser, J., Calverley-Range, E.A.,
1301 Koster, E.H., 1987. Inclined heterolithic stratification-terminology,
1302 description, interpretation and significance. Sedimentary Geology, 53 (1-
1303 2), 123-179.

1304 Tintant, H., 1984. Autochtonie ou allochtonie chez les Céphalopodes. Mém.
1305 Géol. Univ. Dijon, 7 (1982): 257-271.

1306 Vail, P.R., Audemard, F., Bowman, S.A., Eisner, P.N., Perez-Cruz, C., 1991.
1307 The stratigraphic signatures of tectonics, eustasy and sedimentology - an
1308 overview. In: Einsele, G., Ricken, W., Seilacher, A. (Eds.), Cycles and
1309 Events in Stratigraphy. Springer, Berlin, 617-659.

1310 Van de Schootbrugge, B., McArthur, J.M., Bailey, T.R., Rosenthal, Y., Wright,
1311 J.D., Miller, K.G., 2005. Toarcian anoxic event: an assessment of global
1312 causes using belemnite C isotope records. Paleoceanography, 20(3),
1313 PA3008.

1314 Vaslet, D., 1987, Geologic du Paleozoique; Permien Superieur, Trias,
1315 Jurassique; lithostratigraphic: in Histoire geologique de la bordure
1316 occidentale de la plate-fornie arabe du Paleozolque inferieur au
1317 Jurassique superieur (Y.M. Le Nindre, J. Manivit and D. Vaslet, authors),
1318 DSc Thesis, University of Paris VI, 1, 413 p.

1319 Vaslet, D., Brush, J.M., Breton, J.P., Manivit, J., Le Strat, P., Fourniguet, J.,
1320 Shorbaji, H., 1988. Geologic map of the quadrangle Shaqra, sheet 25H
1321 Kingdom of Saudi Arabia: Deputy Ministry for Mineral Resources
1322 Geoscience Map GM-120C, 29.

1323 Vaslet, D., Delfour, J., Manivit, J., Le Nindre, Y.M., Brosse, J.M., Fourniguet,
1324 J., 1983. Geologic map of the Wadi Ar Rayn quadrangle, sheet 23 H,
1325 Kingdom of Saudi Arabia. Saudi Arabian Deputy Ministry for Mineral
1326 Resources, Jeddah, Geosciences Map, GM-63A.

1327 Weimer, R.J., Howard, J.D., Lindsay, D.R., 1982. Tidal flats and associated
1328 tidal channels. Sandstone Depositional Environments: American
1329 Association of Petroleum Geologists, Memoir, 31, 191-245.

1330 Wendler, J.E., Wendler, I., Vogt, C., Kuss, J., 2016. Link between cyclic
1331 eustatic sea-level change and continental weathering: Evidence for
1332 aquifer-eustasy in the Cretaceous. Palaeogeography, Palaeoclimatology,
1333 Palaeoecology, 441, 430-437.

1334 Williams, H.D., Burgess, P.M., Wright, V.P., Della Porta, G., Granjeon, D.,
1335 2011. Investigating carbonate platform types: multiple controls and a
1336 continuum of geometries. Journal of Sedimentary Research, 81(1), 18-37.
1337 Willis B.J., Behrensmeyer A.K., 1994. Architecture of Miocene overbank deposits in northern Pakistan. Journal of Sedimentary Research, 64. 60-67.

1338
1339 Wilson, J.L., 1975. Carbonate Facies in Geologic History. Springer-Verlag, New York, 471 pp.

1342 Wilson, J.L., Jordan, C., 1983. Middle Shelf Environment. In: Scholle, P.A., Bebout, D.G., Moore, C.H. (Eds.), Carbonate Depositional Environments. American Association Petroleum Geologists Memoir, 33, 345-440.

1345 Wright, V.P., 1986. Paleosols their recognition and interpretation. Oxford, Balkwell Scientific, 315.

1347 Yousif, S., Nouman, G., 1997. Jurassic geology of Kuwait. GeoArabia, 2(1), 91-110.

1349 Ziegler, M.A., 2001. Late Permian to Holocene Paleofacies evolution of the Arabian plate and its hydrocarbon occurrences. GeoArabia, 6, 445-504.

1351

1352 **Figure captions**

1353 **Figure 1:** Geological map of the study area showing the Jurassic outcrops modified from Fischer et al. (2001), measured sections, faults and magnetic lineaments. The measured sections are: (1) Khashm Ad Dhibi (N 24.23492°, E 46.09877°), (2) Wadi Al Jufayr (N 23.89844°, E 46.17702°), (3) Faridat Balum (N 23.7114°, E 46.23652°), (4) Khashm Al Khalta (N 23.58547°, E 46.17834°), (5) Khashm Disman (N 23.42942°, E 46.22265°), (6) Wadi Birk (N 23.13083°, E 46.35743°), (7) Fara'id al Ahmar (N 22.56072°, E 46.10331°), (8) Khashm Munayyifiyah (N 22.18176°, E 45.88079°), (9) Khashm Abu Al Jiwar (N 21.84332°, E 45.73633°). The faults are mapped in the 1:250,000-scale quadrangles of Wadi al Mulayh (Manivit et al., 1985a), Wadi Ar Rayn (Vaslet et al., 1983), Darma (Manivit et al., 1985b) and Shaqra (Vaslet et al., 1988). The name of the faults are: f1 Wadi Al Atk Lineament, f2 Al 'Amar Fault, f3 and f4 are belong to the Najd Fault System (Al- Husseini, 2000).

1366 **Figure 2:** Toarcian paleogeographic map showing the area of study: Toarcian paleogeographic map showing the area of study located in the southern margin of the Neo-Tethys Ocean (modified
1369 from margin of the Neo-Tethys Ocean (modified from Thierry et al., 2000; Dera
1370 et al., 2009).

1371 **Figure 3:** Lithostratigraphic, biostratigraphic and sequence stratigraphy of
1372 the Early Jurassic in Jabal Tuwaiq, Saudi Arabia. The biostratigraphical data
1373 is mainly ammonites, and includes: 1) *Protogrammoceras* sp., *Bouleiceras*
1374 sp.; 2) *Nejdia* sp. and *Hildoceras* sp., 3) *Euhoploceras* sp. and *Hyperlioceras*
1375 sp.; 4) *Shirbuirnia* sp., *Dorsetensia* sp. and *Sonninidae* sp. (Modified from
1376 Fischer et al., 2001).

1377 **Figure 4:** Fluvial facies association in the Marrat Formation. A) Pebby
1378 sandstone and conglomerates (F1), base of braided fluvial channel, base of
1379 the Marrat Formation, Wadi Al-Jufair, B and C) Medium to coarse grain trough
1380 cross bedded sandstone (braided channel).

1381 **Figure 5:** Fluvial facies association in the Middle Marrat Formation. A)
1382 Stacked meandering channel-fills, scour base (s arrow), inclined heterolithic
1383 stratification (IHS) (sandstone/shale), Khashm Al Khalta, B) Close-up of the
1384 scour base (s arrow in figure A) shows the IHS, C) Abandoned channel-fill
1385 shows IHS of point bar marked by the lateral grain-size fining trends to the
1386 left, Khashm Disman, D) Siltstone and thin fine-grained sandstone beds (pen
1387 for scale), overbank, Faridat Balum, E) Close-up of the very small ripples
1388 shows climbing- ripple lamination, overbank, Faridat Balum, F) Thinly
1389 laminated red shale with silt laminae, flood plain/lake, Wadi Al Jufayr, G)
1390 Mottled red shale with root traces, paleosol, Khashm Munayyifiyah (Jacob's
1391 staff is 120 cm).

1392 **Figure 6:** Coastal plain facies association (A-E), high-energy nearshore
1393 facies association (F-G). A) Mottled bluish green shale (mud flat/coastal
plain), Lower Marrat, Khashm Disman, B) Stromatolitic lime-mudstone marked at the top by mudcracks (d arrow), mud flat/coastal plain, Lower Marrat, Khashm Ad Dhibi, C) Bioturbated heterolithic silty sandstone shows nodular structure, mixed flat/coastal plain, Upper Marrat, Khashm Al Khalta, D) Small ripples with mud drapes, sand tidal-flat, Upper Marrat, Khashm Al Khalta (note pen for scale), E) Channel-fill sandstone with mud drapes (? IHS) from the same horizon of photo D, tidal creeks, F) Sandstone with *Skolithos* burrows (s arrows), sand tidal-flat/bars, Upper Marrat, Khashm Abu Al Jiwar, G) Sharp base massive sandstone with swaley cross-stratification, storm influenced shoreface, Upper Marrat, Faridat Balum, H) Close-up photo of the swaley cross-stratification in photo G shows chevron structure developed a ripple crest (arrow).

**Figure 7:** Mixed carbonate-siliciclastic inner-lagoon facies association in Khashm Ad Dhibi. A) Grayish green calcareous shale (shale dominated inner lagoon), Upper Marrat (note hammer for scale), B) Argillaceous nodular bioturbated peloidal wackestone/mudstone (carbonate dominated inner lagoon), Upper Marrat, C) Nodular horizontal-bioturbated peloidal wackestone (where the notebook is located) intercalated with highly bioturbated wackestone/mudstone beds, Middle Marrat, D) Top and side view of the bioturbated wackestone/mudstone (highly bioturbated lagoon), Middle Marrat.

**Figure 8:** Vertical facies successions show the evolution of the depositional environments (from fluvial to carbonate inner lagoon) during a 3rd-order marine transgression. A) The Lower Marrat outcrop photo from Wadi Al Jufayr, Marrat composite sequence 1 (MCS1), B) The Middle and Upper Marrat outcrop at Khashm Ad Dhibi, Marrat composite sequence 2 (MCS2).
1419 **Figure 9:** Detailed measured section of the Marrat Formation, A) the lower
1420 and middle Marrat, Marrat composite sequence 1 (MCS1), at Wadi Al Jufayr
1421 section shows the onset of the Jurassic transgression over the
1422 Triassic–Jurassic unconformity. The MFS of MCS1 is placed in the highly
1423 bioturbated nodular peloidal wackestone/mudstone with Early Toarcian
1424 ammonite fauna, B) Fara’id al Ahmar measured section shows the two Marrat
1425 composite sequences MCS1 and MCS2, C) Khashm Munayyifiyah measured
1426 section shows the two Marrat composite sequences MCS1 and MCS2. Base
1427 MCS2 shows typical meandering vertical successions with fining-up trend. For
1428 symbol and facies color legend see Fig. 10, 11 and 12.

1429 **Figure 10:** Detailed core description of the upper Marrat Formation at
1430 Khashm Ad Dhibi section (from DHIBI-1 outcrop core) combined with
1431 biofacies summary and paleoenvironmental interpretation (Hughes, 2009;
1432 unpublished Saudi Aramco report). The succession is characterized by mixed
1433 carbonate- siliciclastic cycles. This core is bounded at the base by fluvial
1434 deposits and at the top by a major unconformity. The section shows initial
1435 transgression over fluvial deposits. The upward-increasing proportion of the
1436 bioturbated carbonate lithofacies reflects an overall marine transgression
1437 trend. The MFS is placed in the thickest beds of highly bioturbated lime-
1438 mudstone.

1439 **Figure 11:** Idealized block diagram shows the Marrat Formation facies
1440 distribution in relation to the shoreline position. The facies are deposited in
1441 very-wide flat inner-platform depositional environments. The diagram is not
1442 meant to show synchronous facies. This is because the depositional
1443 environments are evolving through the successions. For example, tidal creeks
1444 and wide coastal plain were developed lately in the upper Marrat Formation.
1445 High-energy wave-dominated shoreline appears only during late TST,
1446 whereas early TST and HST are characterized by low-energy mud-dominated
1447 shoreline. The bathymetry was estimated by reconstructing the depositional
1448 profile from one of the upper cycles in the cross-section.

1449 **Figure 12:** High-resolution sequence-stratigraphic cross section of the
1450 Marrat Formation along the Jabal Tuwaiq outcrops. The datum is top of the
1451 Marrat unconformity which is overlain by evaporite deposits in the northern
1452 area and silty ferruginous oolite deposits in the southern area. The latitudinal
1453 coordinates are shown at the head of the section as reference points. For
1454 ammonite names see (Fig. 8).

1455 **Figure 13:** A) Sequence-stratigraphic correlation from surface to
1456 subsurface using gamma-ray logs. Detailed facies analysis and sequence
1457 stratigraphy of the Khashm Ad Dhibi are presented in (Figs. 3, 10 and 12)
1458 Paleofacies map of the Early Jurassic (Sinemurian to Aalenian) shows two
1459 correlation trajectories and approximate location of the Jurassic shelf margin
1460 (modified after Ziegler, (2001).

1461 **Figure 14:** Toarcian geological history shows sequence stratigraphy of the
1462 Central Arabia compared with the European domain.

1463 **Figure 15:** Comparison of facies and sequence stratigraphy of the studied
1464 area with average seawater paleotemperature of the European Epicontinental
1465 Sea. The average seawater paleotemperature calculated from several
1466 localities included in the European Epicontinental Sea (Gomez and Goy,
1467 2011). Note: the Khashm Ad Dhibi section is rescaled to fit the
1468 paleotemperature curve.
<figure><img src="image_3.png" /><figcaption>Figure 1</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>Figure 2</figcaption></figure>
<figure><img src="image_5.png" /></figure>
<figure><img src="image_6.png" /><figcaption>Figure 4</figcaption></figure>
<figure><img src="image_7.png" /><figcaption>Figure 5</figcaption></figure>
<figure><img src="image_8.png" /><figcaption>Figure 6</figcaption></figure>

1475

1476
<figure><img src="image_9.png" /><figcaption>Figure 7</figcaption></figure>
<figure><img src="image_10.png" /><figcaption>Figure 8</figcaption></figure>
<figure><img src="image_11.png" /><figcaption>Figure 9</figcaption></figure>
<figure><img src="image_12.png" /><figcaption>Figure 10</figcaption></figure>
<figure><img src="image_13.png" /><figcaption>Figure 11</figcaption></figure>
<figure><img src="image_14.png" /><figcaption>Figure 12</figcaption></figure>
<figure><img src="image_15.png" /></figure>

<figure><img src="image_16.png" /><figcaption>Figure 13</figcaption></figure>
<figure><img src="image_17.png" /><figcaption>Figure 14</figcaption></figure>
<figure><img src="image_18.png" /><figcaption>Figure 15</figcaption></figure>