# Biostratigraphy, carbon isotope and sequence stratigraphy of South Tethyan Valanginian successions in the Essaouira-Agadir Basin (Morocco)

Stéphane Reboulet, Etienne Jaillard, Majd Shmeit, Fabienne Giraud, Moussa Masrour, Jorge Spangenberg

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Stéphane Reboulet, Etienne Jaillard, Majd Shmeit, Fabienne Giraud, Moussa Masrour, et al. Biostratigraphy, carbon isotope and sequence stratigraphy of South Tethyan Valanginian successions in the Essaouira-Agadir Basin (Morocco). Cretaceous Research, 2022, 140, 105341 [27 p.]. 10.1016/j.cretres.2022.105341. hal-03942381

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1 **Biostratigraphy, carbon isotope and sequence stratigraphy of South Tethyan**

2 **Valanginian successions in the Essaouira-Agadir Basin (Morocco)**

3

4 Stéphane Reboulet¹, Etienne Jaillard², Majd Shmeit²,³, Fabienne Giraud², Moussa Masrour⁴,

5 Jorge E. Spangenberg⁵

6

7 1. Univ. Lyon, Univ. Lyon 1, ENSL, CNRS, LGL-TPE, F-69622, Villeurbanne, France

8 2. Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel,

9 ISTerre, 38000 Grenoble, France

10 3. Lebanese University, Doctoral School of Science and Technology, Laboratory of

11 Geosciences Georesources and Environment L2GE, EDST/PRASE, Beirut, Lebanon

12 4. Université Ibn Zohr, Faculté des Sciences, Département de Géologie, BP 8106, Cité

13 Dakhla, Agadir, Morocco

14 5. University of Lausanne, Institute of Earth Surface Dynamics (IDYST), CH-1015 Lausanne,

15 Switzerland

16

17 Corresponding author, S. Reboulet, e-mail address: stephane.reboulet@univ-lyon1.fr

18

19 **Abstract**

20 A detailed stratigraphic analysis was carried out on Valanginian deposits of six Moroccan

21 sections of the Essaouira-Agadir Basin (EAB, South Tethyan margin) in order to characterize

22 the Weissert Event and propose correlations with the North Tethyan margin (south-east

23 France Basin). The studied successions consist of alternating marlstone and limestone beds

24 with sandy intercalations, and are well exposed and relatively rich in ammonites. Ammonite

25 biostratigraphy and sequence stratigraphy were established for all successions, whereas
26 calcareous nannofossil and carbon stable isotope analyses were performed for two and five
27 sections, respectively. For each succession, an accurate ammonite zonal scheme allows to
28 recognize the standard zonation established for the Mediterranean Province. A calcareous
29 nannofossil zonation is provided for Zalidou and Aït Hamouch, considered as reference
30 sections. The detailed biozonations allowed to ascribe an accurate age for most of the
31 sedimentary discontinuities and depositional sequences identified in the EAB. East-west and
32 north-south transects are established for the Valanginian depositional system. Despite some
33 stratigraphic gaps, the Valanginian carbon isotope excursion (CIE) was recognized in most of
34 the studied sections. The Moroccan successions are correlated with those of reference sections
35 of south-east France i.e., the Vocontian Basin (Vergol-La Charce) and Provence Platform
36 (Carajuan), using bio-sequence-chemo-stratigraphy. These inter-basin correlations allowed to
37 evidence major "mid-Valanginian" and upper Valanginian eustatic regressions; the possible
38 role of tectonics and glacio-eustacy is also discussed.
39

39

40

**Keywords**

41 Ammonite, Calcareous nannofossil, Depositional sequence, Weissert Event, Morocco, Inter-basin correlation

43

44

**1. Introduction**

45 Several significant palaeoceanographic, palaeoclimatic and palaeoenvironmental changes are
46 recorded in Valanginian times (Gale et al., 2020). The South Atlantic Ocean began to open
47 and the early stages of rifting were accompanied by extrusion of the Parana-Etendeka large
48 igneous province (Coffin and Eldholm, 1994; Gomes and Vasconcelos, 2021). A cooling of
49 the climate is recorded at least locally (Price, 1999; Pucéat et al., 2003). A biosphere crisis is
50 suspected through a global carbon-cycle perturbation recorded by positive carbon isotope
excursion in marine carbonates and terrestrial organic matter, named the Valanginian
51
Weissert oceanic anoxic event or the Weissert Event (Erba et al., 2004; Gröcke et al., 2005;
52
Kujau et al., 2012). For these reasons, Valanginian successions have been extensively studied
53
in the North Tethyan margin, where numerous detailed lithological, biostratigraphic,
54
sedimentological and isotopic data are available (Lini et al., 1992; Föllmi et al., 1994; Hennig
55
et al., 1999; Sprovieri et al., 2006; McArthur et al., 2007; Gréselle et al., 2011; Charbonnier et
56
al., 2017; Aguado et al., 2018). As a result, reference sections are mainly located in south-east
57
France, such as Vergol (Montbrun-les-Bains, Drôme), candidate section for the Valanginian
58
Global Boundary Stratotype Section and Point (GSSP, Blanc et al., 1994; Kenjo et al., 2021)
59
and La Charce (Drôme), GSSP for the Hauterivian (Mutterlose et al., 2020). Elsewhere,
60
however, integrated studies are quite rare (e.g., Aguirre-Urreta et al., 2019), and works on the
61
Valanginian period focused on ammonite biostratigraphy (e.g., Rawson, 2007), calcareous
62
nannofossils zonation (e.g., Bralower, 1987; Bralower et al., 1989), synsedimentary tectonics
63
(e.g., Masse and Lesbros, 1987; Gradinaru et al., 2016), sedimentary geochemistry and
64
palaeoclimatology (e.g., Pucéat et al., 2003; Charbonnier et al., 2020).
65

In the South Tethyan margin of Africa, Lower Cretaceous deposits are commonly represented
66
by clastic subaerial sediments (“Continental Intercalaire”, Lefranc and Guiraud, 1990; Fanti et
67
al., 2012; Newell et al., 2015), and marine sediments are restricted to the distal parts of the
68
North-African margin. However, the latter are often deformed by the Alpine orogeny (Frizon
69
de Lamotte et al., 2000) that makes difficult their study. Therefore, the Valanginian series are
70
poorly known, and the Weissert Event is not documented by carbon isotope data, in spite of
71
some integrated stratigraphy studies in northern Tunisia (Soua, 2016; Melliti et al., 2019; Ben
72
Ammar and Layeb, 2021). The Moroccan Essaouira-Agadir Basin is located at the western
73
edge of the High Atlas Mountain Range and on the Atlantic coast of Morocco. The basin
74
belonged, therefore, to the southern margin of the Mesozoic Tethys Ocean. It offers a rare
75
opportunity to study the Valanginian stage, since it presents excellent outcrops ranging from outer shelf to nearshore environments (Ferry et al., 2007) and the Valanginian successions are rich in ammonites (Wippich, 2003; Ettachfini, 2004). Recently, the mid-Valanginian carbon isotope excursion has been identified for the first time in the deposits of the Essaouira-Agadir Basin (Shmeit et al., 2022). Six sections located in this basin provide ideal successions for an integrated approach owing to the well-exposed outcrops and relatively abundant ammonite records. The sections were also chosen to establish two transects: one in a south-north direction with Aït Hamouch, Zaouia Sidi Abderahmane and Zalidou; and one in a west-east direction with Obbay, Igouzoulen and Ida w Iddar. Except for the two latter sites, the successions were studied mainly for the ammonite content by Wippich (2001; 2003) and/or Ettachfini (2004).

The main goals of the study were: (1) to establish a well-constrained integrated stratigraphic framework of the upper Berriasian-lowermost Hauterivian interval of the Essaouira-Agadir Basin, based on a high-resolution biostratigraphy involving ammonite and calcareous nannofossil biozonations, and carbon isotope stratigraphy, thus allowing a characterization of the Weissert Event in the South Tethyan margin; (2) to define time lines, based on the analysis of the evolution of sedimentary depositional environments, discontinuity surfaces and sequence analysis; and (3) to correlate the studied sections of the Essaouira-Agadir Basin with those of south-east France Basin in order to discriminate local from global factors, that influence sedimentary palaeoenvironments.

To shorten the manuscript, some abbreviations are used. Essaouira-Agadir Basin, EAB. South-east, SE. Formation, Fm. Sequence boundary, SB. "Discontinuité du Valanginien moyen", DVM. "Discontinuité du Valanginien supérieur", DVS. "Discontinuité du Valanginien terminal", DVT. "Discontinuité au toit des Calcaires Blancs", DCB. Hummocky cross stratification, HCS. First occurrence, FO. Last occurrence, LO. First appearance datum,
101

FAD. Last appearance datum, LAD. For the ammonite zonation: Standard zone, StZ;

102

Standard subzone, StSz; Local subzone, LSz. Carbon isotope excursion, CIE. Deep Sea

103

Drilling Project, DSDP. For the stratigraphic position of fossils, an alphanumeric notation is
used with the abbreviation of the name of the section followed by the bed number: Aït

104

105

Hamouch, AH or AtH; Zalidou, ZA; Zaouia Sidi Abderahmane, ZS; Igouzoulen, IGb or IGz;
Ida w Iddar, IW; Obbay, OB.

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## 2. Geological setting

109

The EAB belongs to the Western Atlas Chain. It is part of the Atlantic passive margin, the
evolution of which can be divided into a rifting phase (Late Permian–Late Triassic), a drifting
phase (Early Jurassic–Turonian) and an Atlasian deformation period. The first compressional
deformation was of Santonian–Campanian age, followed by the Eocene–Pleistocene Alpine
deformation which gently folded the EAB (Guiraud and Bosworth, 1997; Algouti et al., 1999;
Frizon de Lamotte et al., 2000; 2009; Zühlke et al., 2004; Hafid et al., 2008). During the Early
Cretaceous, the EAB was dominated by an extensional regime (Le Roy et al., 1998) and a low
thermal subsidence rate (Ellouz et al., 2003; Bouatmani et al., 2007). After drowning of the
Upper Jurassic–Berriasian carbonate shelf, deposition in the EAB is first dominated by marl
accumulation with scarce limestone beds (Valanginian–Hauterivian), then by a marlstone-
limestone succession (Barremian–Aptian) with a coarse sandy intercalation (upper Barremian)
and finally, by a thick shaly series (Albian) capped by upper Albian limestones (Ambroggi,
1963; Wiedmann et al., 1982; Canérot et al., 1986; Rey et al., 1988; Witam, 1998; Bourgeoini
et al., 2002; Ferry et al., 2007; Luber et al., 2017; Jaillard et al., 2019a; 2019b; Gale, 2020).

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In the EAB, west-sloping Mesozoic strata rest on the Hercynian rocks of the High Atlas (Fig.
1). The EAB comprises two main, east-west trending folds, which divide it in three parts. The
southern part constitutes the southern flank of the Imouzzer anticline, the core of which offers

124

125
126 large outcrops of Jurassic rocks. The central part is comprised between the Imouzzer and the
127 Amsittene anticlines, and includes a mild anticline located south of Tamanar (Fig. 1). The
128 northern part is located north of the Amsittene anticline and has not been studied here.

129 The first comprehensive works to understand the stratigraphy of the EAB were by Roch
130 (1930) and Ambroggi (1963) who provided major contributions, and Duffaud et al. (1966).

131 An overview of the Cretaceous sedimentary succession of the EAB has been given by
132 Wiedmann et al. (1982). According to Duffaud et al. (1966), Rey et al. (1986; 1988) and Taj-
133 Eddine et al. (1992), the uppermost Tithonian-lowermost Hauterivian interval comprises four
134 formations (Fig. 2). The Cap Tafelney Fm is made of bryozoan-rich limestones overlain by
135 calpionellid-rich limestone beds, which allowed to ascribe the unit to the uppermost
136 Tithonian-Berriasian. The fossiliferous Aghroud Oudar Fm (lower Valanginian), comprises
137 alternating marlstone and argillaceous limestone beds. The Sidi Lhoussaine Fm, ascribed to
138 the upper Valanginian and lower Hauterivian, consists of green marlstone, with few limestone
139 beds at the base and sand beds at the top. The Tamanar Fm (lower Hauterivian), is defined as
140 a reefal limestone unit. The limits of these units, however, are not well defined.

141 Detailed palaeontological studies based on ammonites of the uppermost Berriasian-lowermost
142 Hauterivian interval have been performed by Ettachfini (1991; 2004) and Wippich (2001;
143 2003). Their rigourous works on the systematics of Valanginian fauna allowed to show
144 taxonomic misinterpretations of some Valanginian neocomitids and olcostephanids, and to
145 propose new bio-chronostratigraphic results. For example, Wippich (2003) recognized most
146 of the ammonite (sub-)zones of the standard zonation of the Mediterranean Province proposed
147 by Hoedemaeker et al. (2003). Wippich (2003) identified, for the first time, ammonite
148 markers to characterize the Valanginian-Hauterivian boundary that is placed within a thick
149 marly series corresponding to the Sidi Lhoussaine Fm of Rey et al. (1986; 1988).
From a sedimentological point of view, Rey et al. (1986; 1988) identified two major sedimentary discontinuities, at the top of the Berriasian Cap Tafelney Fm, and at the base of the lower Hauterivian Tamanar Fm, respectively. Minor discontinuities are also mentioned in the upper part, and at the top, of the Aghroud Oudar Fm (lower Valanginian), and within the Sidi Lhoussaine Fm (upper Valanginian–lower Hauterivian). These authors also determined a transgressive trend at the base of the Valanginian, and a transgressive trend through Valanginian times, locally interrupted by an emergence period near the lower–upper Valanginian boundary. Ferry et al. (2007) provided detailed, well-dated sections of the Berriasian–Hauterivian series (Fig. 2). They interpreted the Valanginian series as deposits of a shallow mixed, carbonate-clastic shelf. According to these authors, the Berriasian and lower Valanginian deposits are an overall east-ward retrograding system. The base of the upper Valanginian shows a significant transgressive trend, and the lowermost Hauterivian is marked by a sudden subsidence pulse which causes a new transgression, followed by a major progradation in the upper part of the lower Hauterivian (Fig. 2; Ferry et al., 2007).

## 3. Materials and methods

Among the six studied sections, one is located in the southern part of the basin, while the other sections belong to its central part; their GPS coordinates are given in Appendix A, (Tab. A1, Supplementary material). Altogether, they define a north–south and an east–west profile (Fig. 1). These sections correspond to the external part of the EAB. For an east–west profile of the southern part of the EAB, see Ferry et al. (2007). The Zalidou section is located north–east of the village Ida w Tghouma and was already described by Ettachfini (2004). The Aït Hamouch and Zaouia Sidi Abderahmane sections are located on the southern and northern side of the Imouzzer anticline, respectively. The former was described by Wippich (2001; 2003), Ettachfini (2004) and Ferry et al. (2007), and the latter corresponds to the Zaouia Sidi
Abd-er-Rahmane and Taourirt Oubazine sections of Wippich (2001; 2003) and to the Zawiat Si Abd A-Rahmane of Ettachfini (2004). The Igouzoulen section has been studied along the Igouzoulen river, a few km west of the Tamanar-Smimou road. The Ida w Iddar and Obbay sections belong to the southern flank of the Amsittene anticline. The latter was already studied by Ettachfini (2004).

The fossils and rock samples were collected in Morocco and exported in France within the framework of the project "MA/13/291-PHC-Volubilis" and according to the national legislation of Moroccan authorities; documents and sampling-export certifications are given in Appendix B (Supplementary material).

**3.1. Sedimentology.** The sections were studied and measured bed by bed. Most sedimentological observations (lithology, texture, sedimentary features, macrofossil content, bioturbation, minerals) were made on the field. Samples were collected in limestone beds, and thin sections were prepared for microfacies analysis. Because the Valanginian-lowermost Hauterivian succession is mainly made of marlstone, facies were chiefly defined through field observations, locally completed by few microfacies analysis of limestone beds.

**3.2. Ammonites.** 1344 specimens of ammonites were recolted in the six studied sections; no aptychus has been observed. The sampling was mainly done from Valanginian limestone beds. The uppermost part of the Berriasian and the basal part of the Hauterivian were also sampled in some sections. Only specimens well-preserved enough to allow an identification were transferred to the laboratory (Lyon, France), where extraction was completed using a vibratory device, and determination was effectuated using a palaeontological worksheet. Specimens doubtfully identified are indicated by a question mark. Dissolution of shells is usual and ammonites are generally preserved as internal calcareous moulds. Lower
200 Valanginian ammonites are relatively well preserved and may reach a large size. Upper
201 Valanginian specimens are more often fragmented and crushed. A few dozens of pyritized
202 specimens were found in marlstone of the upper Valanginian. The specimens are recorded as
203 “Collection Reboulet” with the label “UJF-ID” that means “Université Joseph Fourrier –
204 Institut Dolomieu” belonging to the OSUG Collections; OSUG-COLLECTIONS is a database
205 of rocks, minerals and fossils (https://web.collections.osug.fr, OSUG, UGA.
206 doi:10.5072/OSUG-COLLECTIONS.all).

207

208 **3.3. Calcareous nannofossils.** A total of 90 and 55 samples, selected from calcareous clay to
209 limestone, and collected in the Zalidou and Aït Hamouch sections, respectively, were
210 investigated for calcareous nannofossil biostratigraphy (Shmeit et al., 2022; this work). These
211 two sections are more extended and are characterized by more marly intervals with respect to
212 the other sections; and were, therefore, more suitable for nannofossil sampling. Studied
213 samples from the composite Aït Hamouch section corresponded to the “AH” section, except
214 for the interval between 32 and 42 m, where the studied samples were collected from the
215 “AtH” section. Methods of smear slide preparation, counting and evaluation of the
216 nannofossil preservation, as well as taxonomic framework and zonations used here were
217 described in Shmeit et al. (2022). The smear slides are numbered as “UJF-ID” (Université
218 Joseph Fourrier – Institut Dolomieu) and curated in the OSUG Collections (for the database,
219 the URL is indicated in part 3.2).

220

221 **3.4. Carbon stable isotopes.** The analysis was performed on 291 whole rock samples from
222 the studied sections, except Obbay, at the stable isotope laboratories of the Institute of Earth
223 Surface Dynamics of the University of Lausanne. Analyses where done using a Thermo
224 Fisher Scientific Gas Bench II carbonate preparation device connected to a Delta Plus XL
isotope ratio mass spectrometer. The CO₂ extraction was done at 70°C. The carbon isotope ratios were reported in the delta (δ) notation as the per mil (‰) relative to the Vienna Pee Dee belemnite standard (VPDB), where δ = (Rsample – Rstandard)/Rstandard and R = ¹³C/¹²C.

The measured δ¹³Cₚcarb values were normalized to the VPDB scale by calibration of the reference gases and working standards with international reference materials NBS 18 (carbonatite, δ¹³C = -5.01 ‰) and NBS 19 (limestone, δ¹³C = +1.95 ‰). Analytical uncertainty (1 sigma), monitored by replicate analyses of the international calcite standard NBS 19 and the laboratory standard Carrara Marble (δ¹³C = +2.05 ‰) was not greater than +/-0.05‰ for δ¹³C.

234

## 4. Results and interpretations

### 4.1 Ammonite stratigraphy: zonation and chronostratigraphic subdivisions

The ammonite fauna of the six studied Moroccan sections (Figs. 3–8) consists of 33 genera grouped into 7 families, using the supra-classification proposed by Klein (2005) and Klein et al. (2007; 2009), partly modified. The classification used here and the authorship of generic and specific names are shown in the taxonomic list provided in Appendix C (Supplementary material). The systematic revision of species was mainly based on the monographies of Le Hégarat (1973), Company (1987), Bulot (1995), Reboulet (1996), Joly (2000), Wippich (2001), Ettachfini (2004), Busnardo (in Gauthier et al., 2006) and Kenjo (2014). Further information on stratigraphy and taxonomy is available in the papers by Thieuloy (1977), Busnardo and Thieuloy (1979), Thieuloy et al. (1990), Reboulet et al. (1992), Thieuloy and Bulot (1992), Bulot et al. (1993), Bulot and Thieuloy (1995), Aguirre-Urreta and Alvarez (1999), Reboulet and Atrops (1999), Busnardo et al. (2003), Wippich (2003), Reboulet (2008), Company and Tavera (2015), Mourgues et al. (2015), Aguado et al. (2018) and
249

Vašíček (2020). Palaeontological comments and illustrations are given for some taxa in Appendix D (text and Figs. D1–D7, Supplementary material).

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The analysis of the ammonite stratigraphic distribution allowed to establish a zonal scheme for the studied sections. The standard ammonite zonation built by the International Union of Geological Sciences Kilian Group (Hoedemaeker et al., 2003; Reboulet et al., 2006; 2009; 2011; 2014; 2018) for the Mediterranean Province of the Mediterranean-Caucasian Subrealm (Tethyan Realm) is applied here. Only two regional units are added, namely the *N. subtenuis* and *B. campylotoxus* local subzones, in order to make easier the comparisons with previous works of Wippich (2001; 2003) and Ettachfini (2004). The ammonite zones are interval zones and are defined by the interval between the FAD of two successive ammonite-indices (Hedberg, 1976). In order to correlate more precisely biostratigraphic subdivisions with ammonite evolution, the boundaries of the Valanginian interval zones correspond to major changes in the ammonite fauna (Reboulet and Atrops, 1999, Kenjo, 2014; Company and Tavera, 2015; Kenjo et al., 2021); this allows a better faunal characterization of the zones.

The chronostratigraphic subdivisions (Berriasian-Valanginian, lower-upper Valanginian and Valanginian-Hauterivian boundaries) are characterized in terms of ammonite markers.

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**The *Tirnovella alpillensis* Standard Zone – uppermost Berriasian.** According to the Kilian Group (Reboulet et al., 2018), the *T. alpillensis* StZ is the last zone of the Berriasian (for detailed information see Kenjo et al., 2021). The index-species was found in the Zalidou, Zaouia Sidi Abderahmane and Obbay sections (Figs. 3, 5, 8). However, as the sampling was low in the lower part of the successions, the FO of *T. alpillensis* cannot be used here to place the base of the zone. Also, the *T. alpillensis* StZ is more or less well-recognized in the studied sections by the occurrence of some quite characteristic taxa of the upper Berriasian like *Fauriella boissieri*, *Berriasella calisto*, *Malbosiceras rouvillei*, *Pomaliceras breveti*,

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273
274 *Spiticeras bulliforme*, *Spiticeras ducale*, *Kilianiceras gratianopolitense*, *Negreliceras* sp.,

275 *Groebericeras* sp., *Ptychophylloceras (Semisulcatoceras) semisulcatum*, *Holcophylloceras*

276 *silesiacum* and *Lytoceras honnoratianum*.

277 **The "Thurmanniceras" pertransiens Standard Zone and the Neocomites premolicus**

278 **Standard Subzone – Base of the Valanginian stage.** Few specimens of "*T.*" *pertransiens*

279 were found in the Zalidou, Aït Hamouch, Igouzoulen and Obbay sections (Figs. 3–4, 6, 8). In

280 the latter site, the FO of this index-species is used to identify the base of the "*T.*" *pertransiens*

281 StZ and thus the lower boundary of the Valanginian (OB13). Kenjo et al. (2021) discussed the

282 choice of the primary marker to define the base of this stage, and gave the priority to the FAD

283 of "*T.*" *pertransiens* rather than the FAD of *Calpionellites darderi*. As the index-species of

284 "*T.*" *pertransiens* is rare or even absent in most of the Moroccan sections, the base of the zone

285 can be placed with the FO of *N. premolicus* (Ettachfini, 2004; this work, ZA20, AH60, ZS34,

286 IGz18; IW5; Figs. 3–7). Taking in account the systematic and biostratigraphic characteristics

287 of *N. premolicus* shown by Ettachfini (2004), Kenjo (2014) and Company and Tavera (2015),

288 the Kilian Group agreed to introduce the *N. premolicus* Subzone in the standard zonation

289 (Reboulet et al., 2018). This subzone starts at the base of the "*T.*" *pertransiens* StZ and ends at

290 the LO of *N. premolicus*. Because the upper part of the zone is not characterised by a subzone

291 for the moment, the *N. premolicus* StSz is provisionally considered as a total range subzone.

292 For Wippich (2003), the simultaneous FO of *N. premolicus* and the genus *Sarasinella* is a

293 workable alternative to put the base of the "*T.*" *pertransiens* StZ. Except for *Sarasinella*

294 *trezanensis* that would appear in the uppermost part of the Berriasian, Ettachfini (2004; tab. 5,

295 p. 82) also noted the co-occurrence of "*T.*" *pertransiens*, *N. premolicus*, *Sarasinella eucyrta*

296 and *Sarasinella longi* at the base of the Valanginian. The simultaneous FO of *N. premolicus*

297 with *S. longi* or *S. eucyrta* are recorded at the base of the "*T.*" *pertransiens* StZ in the Zalidou

298 and Aït Hamouch sections, respectively (Figs. 3–4). These two species of *Sarasinella* and *S.*
trezanensis are also recorded in the rest (mainly in the lower part) of the "T." pertransiens StZ in most of the studied sections (Figs 3–5, 7–8). In most of the Moroccan studied sections (Figs. 3–6, 8), "Thurmanniceras" gratianopolitense takes place in the "T." pertransiens StZ; in Aït Hamouch, Igouzoulen and Obbay sites, this species first occurs at the base of the zone. Considering that the specimens of "Thurmanniceras" thurmanni studied by Wippich (2001; 2003) may be (partly?) interpreted as "T." gratianopolitense (see Kenjo et al., 2021), it seems that this species could appear in the *T. alpillensis* StZ as shown in figures of synthetic ranges of taxa provided by Wippich (2001, tab. 15; 2003, fig. 10). According to his sections showing ammonite ranges, "T." thurmanni occurs in the "T." pertransiens StZ, except in Addar, where the appearance of "T." thurmanni occurs in bed 105 dated from the uppermost part of the Berriasian by this author. The specimen illustrated in Wippich (2001, "T." thurmanni, pl. 20, fig. 1) and sampled in layer 105 is here interpreted as "T." gratianopolitense. The layer 105 of Wippich (2001) could be dated from the "T." pertransiens StZ as the last typical Berriasian taxa occur in layer 104 and the first typical Valanginian taxa appear just above in layer 106. Moreover, it seems that Wippich (2001; 2003) identified the base of the "T." pertransiens StZ in the Aït Hamouch section with the FO of his "T." thurmanni. Ettachfini (2004; tab. 5) also indicated the occurrence of "T." gratianopiltense in the uppermost part of the Berriasian. In his sections showing the ammonite distributions (Addar, Sidi Yahia Ou Saïd, Zalidou, and Akoui Griz), specimens of this species were found in the top part of the *T. alpillensis* Subzone; however, at least for some of these sections, this interval could be alternatively dated as lowermost Valanginian. The difference in the ranges of "T." gratianopolitense (Wippich (2001; 2003) and Ettachfini (2004) versus Company and Tavera (2015) and this work), may be also explained by a different conception of this species. Four specimens of *Thurmanniceras*? were found in the *T. alpillensis* StZ of the Ida w Iddar section (Fig. 7, IW2b); they may correspond to true "T." thurmanni, as this species is recorded in the
uppermost part of the Berriasian by Ettachfini (2004). These comments on the stratigraphic
distribution of *Thurmanniceras* around the Berriasian–Valanginian boundary interval show
that a revision of this genus is needed. Regarding *Kilianella*, this genus is only observed in the
upper part of “*T.*” *pertransiens* StZ in the Aït Hamouch (Fig. 4) and Ida w Iddar sections (Fig.
7; one specimen of *Kilianella lucencis*?). This is in accordance with other data on the
Moroccan western High Atlas given by Ettachfini (2004; occurrence of *Kilianella* sp. 1 in the
upper part of his *N. premolicus* Zone); Wippich (2001; 2003) did not record *Kilianella* in the
“*T.*” *pertransiens* StZ. In summary, the (co-) occurrences of “*T.*” *pertransiens*, “*T.*”
*gratianopolitense*, *N. premolicus*, *S. longi* and/or *S. eucyrta* allow to place the base of the
Valanginian and provide a good characterisation of the “*T.*” *pertransiens* StZ of all the studied
sections (Figs. 3–8).

**The Neocomites neocomiensiformis Standard Zone; Neocomites subtenuis and Busnardoites campylotoxus local subzones.** The *N. neocomiensiformis* StZ is applied for the first time in the Moroccan lower Valanginian successions. It could not be integrated in the zonal schemes of Wippich (2003) and Ettachfini (2004) as this zone was proposed by Company and Tavera (2015). This index-species is relatively rare and only found in the upper part of the zone in the Zalidou, Aït Hamouch, Igouzoulen, Ida w Iddar and Obbay sections. Consequently, the base of the zone is identified in the six studied Moroccan sections by the FO of *N. subtenuis* (Figs. 3–8, ZA25, AH72, ZS43b, IGz23, IW15b and OB18) as its appearance is contemporaneous with that of *N. neocomiensiformis* in SE Spain (Company and Tavera, 2015). In terms of stratigraphic interval, the *N. subtenuis* LSz (Ettachfini, 2004) used here corresponds to the *Baronnites hirsutus* Subzone proposed by Company and Tavera (2015). Indeed, the FO of *N. subtenuis* is simultaneous to that of *B. hirsutus* (Company and Tavera, 2015) and the upper boundary of these subzones is defined by the FAD of *B. campylotoxus* (Ettachfini, 2004) and *Valanginites dolioliformis* (Company and Tavera, 2015),
respectively; according to the latter authors, the appearance of these both species is contemporaneous. It is difficult to characterize the *N. subtenuis* LSz in the Moroccan sections because the assemblage is poor and *B. hirsutus* was not identified (Wippich, 2001; 2003; Ettachfini, 2004; this work). In the *N. subtenuis* LSz, rare *Sarasinella uhligi* and/or *Karakaschiceras paraplesium* have been recorded in the Zalidou, Aït Hamouch and Igouzoulen sections (Figs. 3–4, 6). The occurrence of *S. uhligi* in the zonal scheme of Wippich (2003, fig. 10) allows to identify the *N. subtenuis* LSz in the upper part of his “*T.*” *pertransiens* StZ. In the same interval, specimens identified by Wippich (2001; 2003) as *N. neocomiensis* may be partly interpreted as *N. subtenuis*. The range of *K. paraplesium* is concordant with that observed in SE Spain (mainly in the *B. hirsutus* Subzone of Company and Tavera, 2015, fig. 7). In the Aït Hamouch and Ida w Iddar sections (Figs. 4, 7), *Kilianella roubaudiana* is recorded in the *N. subtenuis* LSz. Some specimens identified with doubt to *Luppovella* were observed in the lower part of the *N. subtenuis* LSz in the Aït Hamouch section (Fig. 4). This agrees with the data of Ettachfini (2004) as this author observed the appearance of this genus at the base of this subzone. However, contrary to the observation made in SE Spain by Company and Tavera (2015, fig. 7), *Luppovella superba* has never been recorded in the upper part of the “*T.*” *pertransiens* StZ of the Moroccan series (Wippich, 2001; 2003; Ettachfini, 2004; this work). This is in agreement with Kenjo (2014) and Kenjo et al. (2021), who noted in SE France the FO of *L. superba* in the *N. neocomiensiformis* StZ (see also Bulot (1995), who indicated this event in his *Olcostephanus stephanophorus* Zone). In the upper part of the *N. neocomiensiformis* StZ, the base of the *B. campylotoxus* LSz is placed at the FO of its relatively abundant index-species (Figs. 3–8, ZA29, AH78, ZS47, IGz26a, IW19 and OB21). Also, this subzone is well characterized by *L. superba* and numerous *Olcostephanus guebhardi* (first acme of this olcostephanid; Zalidou, Aït Hamouch, Zaouia Sidi Abderahmane, Igouzoulen and Ida w Iddar, Figs. 3–7). This assemblage is observed by
Wippich (2001; 2003) and Ettachfini (2004). In agreement with these authors, the last occurrences of *Luppovella* and/or *Kilianella* are recorded in this subzone, as well illustrated in the Aït Hamouch, Igouzoulen and Ida w Iddar sections (Figs. 4, 6-7). *Busnardoites subcampylotoxus?*, *Neohoploceras depereti* and *Lytoceras juilleti* were recorded (only one specimen for each species) in the Zalidou and Aït Hamouch sections (Figs. 3-4). The *B. campylotoxus* LSz corresponds, in terms of stratigraphic interval, to the *V. dolioliformis* Subzone of Company and Tavera (2015). Indeed, according to these authors, the FOs of both index-species are simultaneous and the upper limit of these subzones is defined by the FO of *Karakaschiceras inostranzewi* (see also Ettachfini, 2004; this work). However, *V. dolioliformis* is only recorded in the *B. campylotoxus* LSz of the Aït Hamouch and Igouzoulen sections (Figs. 4, 6).

**The Karakaschiceras inostranzewi Standard Zone.** The base of this zone is placed at the FO of its index-species (Figs. 3-8, ZA34a, AH87, ZS50, IGz27a, IW26 and OB22). The *K. inostranzewi* StZ corresponds to the *Karakaschiceras biassalense* Zone of Wippich (2001; 2003) and Ettachfini (2004). According to these authors, the fauna of this stratigraphic interval is little diversified. Among neocomitids, the FO of *Neocomites neocomiensis*, *Neocomites teschenensis* and *Neocomites platycostatus* are recorded in this zone at Zalidou and Obbay (Figs. 3, 8). Few *Neohoploceras* (FO of *Neohoploceras provinciale*; Aït Hamouch, Ida w Iddar and Obbay sections, Figs. 4, 7-8) are also represented. Bulot and Thieuloy (1995), Company and Tavera (2015) and Aguado et al. (2018) also recorded the FO of *N. provinciale* in the basal part of the *K. inostranzewi* StZ. Specimens of *O. guebhardi* (beginning of the second acme) were found in most sections (Figs. 3-5, 8).

**The Saynoceras verrucosum Standard Zone; the S. verrucosum and Karakaschiceras pronecostatum Standard subzones – Base of the upper Valanginian substage.** Wippich (2003) and Ettachfini (2004) emphasized the difficulty to identify the base of the S.
399 *verrucosum* StZ due to the scarcity of the index-species in the Moroccan successions. For
400 example, only a single specimen was found by Wippich (2001; 2003; Tarourirt Oubazine
401 section). Moreover, as noted by this author, the succession is highly condensed and the
402 thickness is much reduced around the lower (*K. inostranzewi* StZ)–upper (*S. verrucosum* StZ)
403 Valanginian boundary (see also this work). As the identification of this boundary is
404 problematic in the western High Atlas, Ettachfini (2004) chose to place the base of the upper
405 Valanginian at the base of his *K. biassalense* Zone, as suggested by Bulot and Thieuloy
406 (1995) at the base of their *K. inostranzewi* Zone in SE France. Even though no specimen of *S.
407 verrucosum* was found in the six studied Moroccan sections (Figs. 3–8), this suggestion was
408 not followed here to agree with the standard zonation and its chronostratigraphic subdivisions
409 (Reboulet et al., 2018). In absence of *S. verrucosum*, the (base of the?) *S. verrucosum* StZ is
410 identified by the (first) occurrence of *Valanginites ventrotuberculatus* as recorded in the
411 Zaouia Sidi Abderahmane (ZS52), the Igouzoulen (IGz27c), and Obbay (OB24) sections
412 (Figs. 5–6, 8). Indeed, according to Company and Tavera (2015), the FOs of both these
413 species are simultaneous in SE Spain; their range ends in the basal part of the *S. verrucosum*
414 StZ and they do not co-occur with *K. pronecostatum* (Aguado et al., 2018), index-species of
415 the second subzone of the *S. verrucosum* StZ. In the Zaouia Sidi Abderahmane and Obbay
416 sections, *V. ventrotuberculatus* is found with *K. pronecostatum*. In the latter section,
417 *Saynoceras contestatum* is also recorded together with *K. pronecostatum* (OB24), as shown in
418 Ettachfini (2004, see tab. 5, p. 82). However their ranges do not overlap in SE France (Bulot
419 and Thieuloy, 1995) and SE Spain (Aguado et al., 2018). As *K. pronecostatum* appears in the
420 upper part of the zone, its co-occurrence with *S. contestatum* and *V. ventrotuberculatus* in
421 some Moroccan sections may be explained by a condensed lithology in the basal part of the
422 upper Valanginian (see above; this work), even though a mistake in the identification of these
423 specimens of *Karakaschiceras* cannot be excluded. For Ettachfini (2004), the base of the *S*.
424 verrucosum StZ is characterized by the FO of O. guebhardi morphe querolensis that is well represented in the lower part of his S. verrucosum horizon. This may correspond, at least 425 partly, to the second acme of O. guebhardi, as observed at Zalidou, Igouzoulen, and Ida w 426 Iddar (Figs. 3, 6-7). In Zalidou and Ida w Iddar sections, the base or the lower part of the S. 427 verrucosum StZ is not well identified due to the absence of ammonite markers (V. 428 ventrotuberculatus and S. contestatum). Thus, the second acme of O. guebhardi might be used 429 to approximate the lower-upper Valanginian boundary; in this case, it could be put at the base 430 of layers ZA36 (Fig. 3; boundary indicated by a dashed line) and IW29 (Fig. 7). This solution 431 is applied for the latter section, in which typical ammonite markers of the lower part of the 432 upper Valanginian are absent. In the Zalidou section, however, the FO of K. pronecostatum 433 (ZA40, boundary indicated by a solid line) is used to place the base of the zone. According to 434 Wippich (2003), N. platycostatus is restricted to the S. verrucosum StZ, as observed in the 435 Zaouia Sidi Abderahmane and Igouzoulen sections (Figs. 5-6). However, this neocomitid is 436 already present in the upper part of the K. inostranzewi StZ in the Obbay section (Fig. 8); 437 similar observations were made in SE France (Reboulet, 1996; Reboulet and Atrops, 1999; in 438 their N. platycostatus Horizon) and SE Spain (Company and Tavera, 2015; in their S. 439 contestatum Subzone). Ettachfini (2004), who considered that N. platycostatus is a junior 440 synonym of N. teschenensis, indicated the FO of this species at the base of the K. inostranzewi 441 StZ. If the (base of the) S. verrucosum StZ cannot be identified by the FO of N. platycostatus, 442 the latter species seems (more) abundant in this zone, as observed in the Zaouia Sidi 443 Abderahmane and Obbay sections (Figs. 5, 8). It can be expected that the distribution of N. 444 platycostatus recorded by Wippich (2003) only corresponds to the highest frequency of this 445 species in the S. verrucosum StZ. As Neocomites gr. platycostatus-teschenensis are relatively 446 well represented in layers ZA36-37 (Fig. 3), this interval of the Zalidou section could be 447 dated to this zone, as previously evoked based on the abundance of O. guebhardi (cf. 2nd 448
acme). However, the lower boundary of this zone cannot be placed using the abundance
variations of some taxa that are partly controlled by palaeoenvironmental conditions (see
Reboulet et al., 2003) and sedimentary factors (cf. condensed layers). At Zaouia Sidi
Abderahmane (Fig. 5), one specimen of *Rodighieroites belimelensis* is recorded in the *S. verrucosum* StZ; this is in agreement with Wippich's data (2003; in *K. pronecostatum* StSz).
In the Igouzoulen section (Fig. 6), *Neohoploceras submartini* occurs in the *S. verrucosum* StZ; Ettachfini (2004) also observed this distribution. Taking into account that the LO of *N. submartini* is recorded in the basal part of the *K. pronecostatum* StSz in SE Spain (Aguado et al., 2018), the base of this subzone in the Igouzoulen section could be placed around the layer IGz29b. However, this should be interpreted carefully as the ranges of *Neohoploceras* taxa show some discrepancies (see Bulot and Thieuloy, 1995; Reboulet, 1996; Wippich, 2001; 2003; Ettachfini, 2004; Aguado et al., 2018); the same remark can be done for the distribution of *Rodighieroites* taxa. In two Moroccan sections, *N. provinciale* occurs in the lower part of the upper Valanginian. At Zaouia Sidi Abderahmane, this species co-occurs with *K. pronecostatum* in the basal part of the *S. verrucosum* StZ (Fig. 5, ZS52-53). According to Bulot and Thieuloy (1995) and Ettachfini (2004), *K. pronecostatum* seems to appear just after the disappearance of *N. provinciale*. Thus, as evoked previously, this Moroccan ammonite assemblage may be interpreted as a result of a condensed lithology and/or a misidentification of some specimens because of the poor preservation of upper Valanginian ammonites. A similar interpretation is made for the Aït Hamouch section, where *N. provinciale* and *K. pronecostatum* also co-occur in layer AH89, with the record of *Neocomites peregrinus* and *K. inostranzewi* (Fig. 4). According to Ettachfini (2004) and Aguado et al. (2018), *K. pronecostatum* and *N. peregrinus* do not co-occur but the ranges given by Bulot and Thieuloy (1995) and Reboulet and Atrops (1999) show a short overlap of both species. Even though there are some discrepancies in the distributions of *Neohoploceras* taxa (see references
above), it seems that *N. provinciale* never occurs with *N. peregrinus*. The layer AH89 is also characterized by the occurrence of few dubious specimens of *K. inostranzewi*?; their preservation might indicate that they have been reworked (cf. discontinuity D5; Fig. 4). To summarize, in most of the studied Moroccan sections, it is difficult to recognize clearly the lower subzone of the *S. verrucosum* StZ (and so its base) due to: a) the absence of the index-species and the rarity of some second ammonite markers as *V. ventrotuberculatus*; b) the condensed lithology and the possibility of reworking material related to the discontinuity D5.

**The Neocomites peregrinus Standard Zone; the *N. peregrinus* and *Olcostephanus nicklesi* Standard subzones.** In the western High Atlas, this zone was identified by Wippich (2001; 2003) and Ettachfini (2004). The index-species is recorded in three sections and its FO allows to place the base of the *N. peregrinus* (Sub-)Zone in the Zalidou (ZA41), Aït Hamouch (AH89), and Zaouia Sidi Abderahmane (ZS57) sections (Figs. 3–5). However, it is relatively difficult to characterize this interval as the ammonite assemblage is poor. When the index-species is absent, the boundary between the *S. verrucosum* and *N. peregrinus* zones can be approximated using the occurrence of *Olcostephanus balestrai* and/or *Oosterella gaudryi* (or *Oosterella* sp. ind.), as made at Igouzoulen (IGz33), Ida w Iddar (IW33) and Obbay (OB25) (Figs. 6–8). The *O. nicklesi* StSz is identified in the Obbay section by the FO of the index-species (OB28). Moreover, pyritized specimens of *Himantoceras acuticostatum* were also sampled in the same layer. The occurrence of *Himantoceras* sp. ind. in the Zalidou section (ZA46, Fig. 3) allows to recognize the *O. nicklesi* StSz. Indeed, these heteromorphs are known in the basal part of this subzone (Bulot and Thieuloy, 1995; Reboulet, 1996; Reboulet and Atrops, 1999; Ettachfini, 2004). According to Wippich (2003), the only record of the *O. nicklesi* StSz corresponds to reworked specimens of *O. nicklesi* and *Himantoceras trinodosum* found in a lag deposit at the base of the *Criosarasinella furcillata* StZ in the Tamri section. For this author, this subzone “falls into an erosional hiatus at least in the west” of the studied
499 area. This author also noted that the interval between the assemblages of the *N. peregrinus*
500 StSz and *C. furcillata* StZ is always rather thin, even in expanded sections, suggesting "a
501 more or less significant non-sequence all over the study area".

502 **The Criosarasinella furcillata Standard Zone; the C. furcillata and Tescheniceras callidiscum standard subzones.** The base of the *C. furcillata* StZ is defined by the FAD of the index-species but it can be identified by the FO of *Criosarasinella* (Reboulet, 1996; Reboulet and Atrops, 1999), as made for three studied sections of the present work (Figs. 3–5; FO in ZA52d, AH96 and ZS60). In the Aït Hamouch and Obbay sections (Figs. 4, 8), *Criosarasinella mandovi* was also observed. In the western High Atlas, these both species were recorded by Wippich (2001; 2003) and Ettachfini (2004). The *C. furcillata* StZ is relatively well characterized by the occurrence of *Tescheniceras subflucticulum*, *Tescheniceras subpachydicranum*, *Neocomites praediscus*? and/or *Olcostephanus densicostatus*. When *Criosarasinella* is absent or rare, as in the Ida w Iddar and Obbay sections (Figs. 7–8), the base of the zone can be placed using the FO of *Tescheniceras* (IW41 and OB29). At Aït Hamouch, Zaouia Sidi Abderahmane and Ida w Iddar (Figs. 4–5, 7), the occurrence of *N. praediscus*? may characterize the *C. furcillata* StSz (for the range of these latter taxa, see Reboulet, 1996; Reboulet and Atrops, 1999). In some sections, *Lytoceras subfimbriatum* and *Neolissoceras grasianum* were also recorded; the last specimens of *Bochianites* (probably *Bochianites neocomiensis*) are found in this zone (Figs. 3–5). These three latter taxa were not observed in the lower Valanginian. The *T. callidiscum* StSz was identified in the Zalidou, Aït Hamouch and Zaouia Sidi Abderahmane sections (ZA55, AH102 and AtH15, ZS67, Figs. 3–5). In the latter section, *Tescheniceras castellanensiforme* was also sampled at the base of the subzone.

522 **The Acanthodiscus radiatus Standard Zone – Base of the Hauterivian stage.** The base of the zone is defined by the FAD of the genus *Acanthodiscus*; this marker defines the base of
the Hauterivian stage (Mutterlose et al., 2020). In the Aït Hamouch (AH103) and Zaouia Sidi Abderahmane (ZS69) sections, the FO of *A. radiatus* and/or *Acanthodiscus vaceki* is used to place the lower boundary of the Hauterivian (Figs. 4–5). Where these species are absent, the FO *Breistrofferella castellanensis* has been considered in the Zalidou (ZA56) and Aït Hamouch (AtH17) sections (Figs. 3–4). In the three sections (Figs. 3–5), the occurrence of *Tescheniceras flucticulum* and *Tescheniceras pachydicranum* allows to characterize the zone. *Oosterella cultrata* (Aït Hamouch, AtH18) and *Olcostephanus densicostatus* complete the assemblage of the basal part of the Hauterivian in the Aït Hamouch (AH103) and Zaoui Sidi Abderahmane (ZS69) sections. In both sections, few poorly preserved ammonites were found in layers AH103 and ZS70. These specimens might correspond to *T. callidiscum*? but there is no clear evidence that they were reworked from underlying levels. Alternatively, these specimens might be identified as *Saynella mucronata*. This species was recorded by Wippich (2003) in the condensed Tamri section, more precisely in the first layer dated from the *A. radiatus* StZ; according to this author, this may indicate a high stratigraphic level within the zone. Thus, if the identification as *S. mucronata* is correct, it seems that only the upper part of the *A. radiatus* StZ is recorded at Aït Hamouch and Zaoui Sidi Abderahmane. However, as noted by Bulot (1995), the representatives of *Saynella* are very rare in Tethyan basins and the range of *S. mucronata* has to be clarified. Even though the *A. radiatus* StZ is partly represented, it may reach a relatively large thickness at Zaoui Sidi Abderahmane as *A. vaceki*, *B. castellanensis* and *T. flucticulum* still occur around 12 m above the Valanginian–Hauterivian boundary.

**Standard zonation and chronostratigraphy.** The current work confirms the reproductibility of the Valanginian standard zonation (Reboulet et al., 2018) and the interest of *N. premolicus* (index-species of the *N. premolicus* StSz) to place the base of the Valanginian when “*T.*” *pertransiens* (index-species of the “*T.*” *pertransiens* StZ) is rare or even absent. Taking in
account data provided by the present study, *N. subtenuis* and *B. campylotoxus* local subzones could be introduced in the standard zonation in order to subdivided the *N. neocomiensiformis* StZ; these first two species are relatively easy to identify, abundant and have a widespread palaeogeographic distribution (see references above). This point might be discussed by the Kilian Group.

554

## 4.2. Calcareous nannofossil stratigraphy

The NK3A, NK3B and NC4A subzones of Bralower et al. (1995) were identified in Zalidou and Aït Hamouch sections (Figs. 3–4). In the latter section, the NC4B Subzone was additionally identified. The CC3a, CC3b and CC4a subzones of Sissingh (1977) were identified in both sections; and the CC4b Subzone was identified only at Aït Hamouch (Shmeit et al., 2022, this work). Nannofossil markers are illustrated in Appendix E (Fig. E1, Supplementary material). Quantitative data on calcareous nannofossils is provided by Shmeit et al. (2022) and can be found online (Supplementary material at https://doi.org/10.1016/j.marmicro.2022.102134).

Detailed biostratigraphic results and interpretations are presented in the current work and not in Shmeit et al. (2022). Although *Calcicalathina oblongata* defines the base of the NK3 Zone, the precise identification of the FO of this species is problematic due to different taxonomic concepts. Its FO is considered to be situated just above the Berriasian–Valanginian boundary (lower part of the “*T.*” *pertransiens*, Duchamp-Alphonse, 2007; Kenjo et al., 2021) or in the lower Valanginian (Aguado et al., 2000). Indeed, Aguado et al. (2000) recognized earlier specimens, called *Calcicalathina praeoblongata*, which occur in the upper Berriasian (*T. alpillensis* StSz); these are very similar in morphology to *C. oblongata* but smaller in average size and with a thick wide wall. However, *C. praeoblongata* figured in Aguado et al. (2000) has been considered by other authors to be overgrown specimens of *Rhagodiscus asper* (see
Kenjo et al., 2021). In the present work, small specimens of *C. oblongata* (< 6 µm) with a thin and bright wall have been recognized in the first samples of the two studied sections; however, in these samples, nannofossils are characterized by large overgrowths which makes more difficult the differentiation between these small forms and larger *C. oblongata*. This species was present in both sections from the first studied sample (*T. alpillensis* p.p. StZ, Zalidou section). The LO of *Rucinolithus wisei*, marking the base of the NK3B Subzone, was observed in the lower part of the upper Valanginian in both sections (*N. peregrinus* StZ at Zalidou and Aït Hamouch, respectively; Figs. 3–4). The LO of *Tubodiscus verenae*, defining the base of the NC4 Zone, was observed in the upper part of the upper Valanginian (uppermost *O. nicklesi* StSz) at Zalidou and in the lower part of the upper Valanginian (uppermost *N. peregrinus* StZ) at Aït Hamouch. The FO of *Lithraphidites bollii*, defining the base of the NC4B Subzone, was observed only at Aït Hamouch in the lowermost Hauterivian p.p. (lowermost *A. radiatus* p.p. StZ). The FO of *E. windii*, which identifies the base of the CC3b Subzone, was observed in the middle part of the lower Valanginian (*N. neocomiensiformis* StZ, *N. subtenuis* LSz) at Zalidou and Aït Hamouch. The FO of *E. striatus*, identifying the base of the CC4 Zone, was observed around the lower–upper Valanginian boundary (*K. inostranzewi* StZ or *S. verrucosum* StZ according to the ammonite biostratigraphic interpretation) at Zalidou and in the lower part of the upper Valanginian (*N. peregrinus* StZ) at Aït Hamouch. The identification of *Eiffelithus striatus* followed Shmeit et al. (2022), such that coccoliths have the length of their long-axes greater than 6.0 µm and with a relatively wide central area (almost 2/3 or greater of coccolith length).

Secondary nannofossil bioevents were also observed. The FO of *Speetonia colligata* was recorded in the uppermost Berriasian p.p. (*T. alpillensis* p.p. StZ, lowermost NK3A and lowermost CC3a subzones) at Zalidou. It was present from the first studied sample at Aït Hamouch. The FO of *Rhagodiscus dekaenelii* was observed in the lowermost Valanginian
599 (lower *N. premolicus* StSz, lowermost NK3A and lower CC3a subzones) at Zalidou. Its FO
600 was recorded slightly later in Aït Hamouch, in the lower Valanginian (upper *N. subtenuis*
601 LSz, lower NK3A Subzone and CC3a/CC3b subzones boundary). The FO of *Hagius peltatus*
602 was observed in the lower Valanginian in both studied sections; in the upper *N. premolicus*
603 StSz (lower NK3A and upper CC3a subzones) at Zalidou, and in the lower *N. premolicus*
604 StSz (lower NK3A and lower CC3a subzones) at Aït Hamouch.
605 At Zalidou, the LO of *R. wisei* is observed in the early upper Valanginian (*N. peregrinus* StZ,
606 *N. peregrinus* StSz, lower CC4a calcareous nannofossil Subzone), and the LO of *T. verenae* is
607 recorded in the uppermost Valanginian (*N. peregrinus* StZ, *O. nicklesi* StSz, upper CC4a
608 Subzone). Accordingly, the NK3B Subzone extends from 22 to 34.8 m (12.8 m thickness;
609 Fig. 3). However, at Aït Hamouch, the NK3B Subzone is considerably reduced, and extends
610 from 38.6 to 39.8 m (1.2 m thickness, Fig. 4). Ammonite biostratigraphy provides additional
611 information such that the *N. peregrinus* StZ is also reduced at Aït Hamouch (~ 7 m) compared
612 with Zalidou (~ 14 m), and the *O. nicklesi* StSz is not recognized at Aït Hamouch (Figs. 3–4).
613 Additionally, there is no lithological evidence of a condensed interval in the upper part of the
614 *N. peregrinus* StZ, where the LOs of *R. wisei* and *T. verenae* have been recognized. This
615 might indicate that a time-interval is missing in Aït Hamouch compared with Zalidou.
616 To synthetize: a sequence of seven nannofossil bioevents has been recognized in the EAB
617 allowing an accurate biostratigraphic framework to be established. They have been correlated
618 with the ammonite zonation. A comparison of this integrated stratigraphy (ammonites and
619 calcareous nannofossils) with other Tethyan basins is shown in the synthetic Figure 9, and is
620 described as follows.

621 **The FO of S. colligata is recorded in the upper Berriasian p.p. (T. alpillensis StZ).** This
622 event has the same age in other basins: the Subbetic Basin (Spain, Aguado et al., 2000), the
623 Neuquén Basin (Argentina; Bown and Concheyro, 2004), the site 1213 (Shatskey rise, Pacific
Ocean; Bralower et al., 2002) and the southern Carpathians (Romania; Melinte and Mutterlose, 2001).

**The FO of *H. peltatus* is recorded in the lowermost Valanginian ("T." *pertransiens StZ*, *N. premolicus StSz*).** In site 1213 (Shatskey rise, Pacific Ocean), this species first occurs in the lower Berriasian (Bralower et al., 2002), i.e. earlier than in the EAB. In the Subbetic Basin, the range of *H. peltatus* starts in the latest lower Valanginian (*K. inostranzewi* StZ, *N. platycostatus* StSz; Aguado et al., 2018); it should be noted that their sampling only concerns the upper part of the *N. neocomiensiformis* StZ and the *K. inostranzewi* StZ. The differences in the FO of *H. peltatus* may be partly explained by its sporadic distribution, as it has been observed in the Valanginian of the EAB.

**The FO of *E. windii* is recorded in the lower Valanginian (*N. neocomiensiformis* StZ).**

This is in accordance with observations of Duchamp-Alphonse et al. (2007) in the Vocontian Basin (SE France, Angles section). In this basin, Bergen (1994) recorded this event slightly later, whereas Kenjo et al. (2021) observed the FO of *E. windii* in the lower part of the "T". *pertransiens* StZ. In other basins, the first record of this species is also dated as lower Valanginian: DSDP 535 (Gulf of Mexico; Bergen, 1994), site 1213 (Shatskey rise, Pacific Ocean; Bralower et al., 2002), Neuquén Basin (Argentina; Bown and Concheyro, 2004) and BGS hole 81/43 (southern North Sea; Kessels et al., 2006).

**The FO of *E. striatus* is recorded around the lower-upper Valanginian boundary.** The age of this event varies according to the geographic locations of the studied sections. It is considered upper Valanginian (former *H. trinodosum* Zone) in the Vocontian Basin (Bergen, 1994; Duchamp-Alphonse et al., 2007), or in the Neuquén Basin (*N. peregrinus* StZ; Bown and Concheyro, 2004), whereas it is uppermost Valanginian in the Boreal Realm (Greenland-Norwegian Seaway; Möller et al., 2015). Moreover, Kessels et al. (2006) recorded the FO of *E. striatus* in the uppermost Valanginian along a N-S transect (BGS hole 81/43 – southern
649 North Sea, DSDP 638 – northern west Spain and DSDP 535 – western Atlantic). Aguado et
650 al. (2018) already suggested that the distribution of *E. striatus* might be controlled by the
651 palaeogeographic distribution of land masses and by the palaeoceanographic currents.

652 **The LO of R. wisei is recorded in the upper Valanginian (N. peregrinus StZ).** In the
653 Subbetic Basin (SE Spain; Aguado et al., 2018), its LO is recorded in the upper Valanginian,
654 but slightly earlier (*S. verrucosum* StZ) than in the EAB. In the Vocontian Basin, its LO is
655 recorded earlier, at the lower–upper Valanginian transition (Bergen, 1994; Duchamp-
656 Alphonse et al., 2007; Gréselle et al., 2011). Discrepancies in the LO of *R. wisei* may be
657 explained by its scarcity at the top of its range (Aguado et al., 2018).

658 **The LO of *T. verenae* is recorded in the upper Valanginian (N. peregrinus StZ, O. nicklesi StSz).** This bioevent is also observed in a similar stratigraphic interval (*O. nicklesi* StSz) both in the Vocontian Basin (Duchamp-Alphonse et al., 2007; Gréselle et al. 2011) and in the Subbetic Basin (Aguado et al. 2018).

662 **The FO of *L. bollii* is recorded in the lowermost Hauterivian (A. radiatus StZ).** This event
663 is observed later (*Crioceratites loryi* StZ) in the Vocontian Basin (Duchamp-Alphonse et al.,
664 2007; Mutterlose et al., 2020) than in the EAB.

665 Among these seven bioevents, three appear synchronous and are reliable for inter-basin
666 correlation: the FOs of *S. colligata* and *E. windii*, and the LO of *T. verenae*.

668 **4.3. Sedimentology and sequence stratigraphy**

669 **4.3.1. Sedimentary discontinuities (Figs. 10–11)**

670 **Karst.** The top of massive limestone beds frequently presents cm- to dm-scale cavities
671 infilled by marly sediment, distinct from the surrounding limestone, that may contain
672 lithoclasts. When the section is visible, cavities usually decrease in size downward and show a
673 random shape. Fossils in the beds may be dissolved and replaced by iron-rich calcite or
674

dolomite. These features are interpreted to result from emergence periods, which caused

675

dissolution and karstification by meteoric water. Moreover, karstified surfaces are locally

676

bored; boring resulted probably from the activity of lithophagous molluscs of intertidal to

677

very shallow environment, during the subsequent marine transgression.

678

**Corrugated surface.** These surfaces are mainly marked by a wavy shape and by reworking of

679

intraclasts in the immediately overlying bed. In the Valanginian succession, they are often

680

observed at the base of thick beds of fine-grained sandstone or of sandy limestone, and also

681

between thin limestone beds and are only marked by the reworking of small-sized intraclasts.

682

These surfaces are interpreted as resulting from the erosion of the underlying bed(s) that can

683

be reworked in the overlying deposits. In the absence of emergence evidence, they are

684

tentatively ascribed to mainly submarine erosion periods.

685

**Limestone to marlstone abrupt lithological change.** In the lower part of the studied series,

686

this kind of surface is usually observed at the top of limestone beds and below a marly

687

succession. It is frequently marked with a phosphate enrichment of the limestone bed in the

688

Berriasian units, and is locally associated with a hardground capping the latter. It is

689

interpreted as traducing a sedimentary hiatus that allowed mineralization (P, Fe) of the bed

690

surface.

691

**Marlstone to sandstone abrupt lithological change.** In the upper Valanginian-lowermost

692

Hauterivian part of the series, lithological change commonly occurs between underlying

693

marlstone and overlying thick beds of sandstone. In this case, it is interpreted as an erosional

694

surface which allowed sandy particles to be loosened from the underlying strata, and then

695

sorted out and deposited in a shallow marine, moderately energetic environment as deposition

696

resumed. Usually, the importance of erosion and the occurrence of emergence periods cannot

697

be assessed. In one case, however, the lack of biostratigraphic bio(sub-)zones suggests

698

significant erosions during a long-lasting period of subaerial erosion.
699 In the following text, sedimentary discontinuities are labelled from D0 to D8 in stratigraphical
700 order.

701

702 **4.3.2. Overview of the Berriasian carbonate shelf sedimentation** (Figs. 10–12)

703 Only the top of this series is dated as upper Berriasian (*T. alpillensis* StZ). Identification of
704 the sedimentary discontinuities allows to recognize two depositional sequences. Although
705 poorly dated, they are tentatively correlated across the studied sections. The far bases of the
706 successions are not illustrated in Figs 10 and 11 but their petrographic content is described
707 below in order to show the sequential evolution. In the southern sections (Aït Hamouch, Sidi
708 Abderhamane, Zalidou), the base of the succession is made of relatively massive limestone
709 beds with thin marlstone interbeds. There, the presence of thick marlstone interbeds and an
710 open marine fauna (plicatulids, terebratulids, large bivalves) would indicate an outer shelf
711 environment. However, the abundance of oysters and shallow-water sedimentary features
712 (laminations, HCS, epikarsts) rather suggests a shallow, open marine depositional
713 environment. In the northern sections (Igouzoulen, Obbay), this succession seems to correlate
714 with massive limestone beds made of pelloid-rich wackestone to packstone, rich in oysters,
715 pinnids and locally oolites. The occurrence of several karstified surfaces, tidal laminations
716 and local desiccation breccias indicates a very shallow, inner shelf environment.

717 **The first sequence (Be1)** is represented by a marly interval in the southern sections. Its base
718 is marked by an abrupt lithological change, and by accumulations of phosphate and
719 intraclasts. It shows a thinning-, then thickening-upward evolution. Marlstone contain
720 brachiopods, pectinids, other bivalves among which *Trichites* sp., echinoids, serpulids, and
721 locally bryozoans, and belemnites, whereas the bioturbated limestone beds present oysters,
722 pinnids, and locally trigonids. Microfacies analysis of limestone beds reveals wackestone
723 textures rich in echinoids and small benthic foraminifers, among which few agglutinated
724 foraminifers, associated with bivalves as oysters, brachiopods and ostracods. This sequence is
725 interpreted as a transgressive then prograding succession, in an open marine outer to inner
726 shelf environment, and witnessing a sea level rise with respect to the underlying deposits. In
727 the Igouzoulen section, this sequence overlies a karstified surface and is dominated by
728 massive limestone beds with thinner marlstone interbeds. In the lower part, pinnids,
729 echinoids, terebratulids and serpulids dominate. In the upper part, thick shelled oysters are
730 dominant, associated with echinoids, pectinids, terebratulids, plicatulids, and finally few
731 ammonites, trigonids and wood fragments. In thin sections, wackestone to packstone textures
732 are predominant and contain a rich fauna of benthic foraminifers, among which are
733 agglutinated forms. The uppermost limestone bed is deeply karstified. In the Obbay section,
734 the upper part of the sequence is made of massive limestone beds containing oysters, trigonids
735 and *Trichites* sp., and is affected by repeated karstification.

736 **The second sequence (Be2)** consists of alternating limestone beds and marlstone interbeds;
737 its upper part is dated as uppermost Berriasian (*T. alpillensis* StZ). Its base (D0) is an
738 erosional surface in the southern sections and a karstified surface in the northern ones. In the
739 southern sections, the lower three quarters of the sequence shows a thinning upward trend,
740 while the upper quarter is slightly thickening upward. In the lower part, fauna is abundant and
741 is dominated by oysters and terebratulids, associated with echinoids, pectinids, plicatulids,
742 other bivalves, and locally *Trichites* sp. and fish teeth. In the upper part, ammonites and
743 terebratulids are dominant, with oysters, pectinids, other bivalves, serpulids and nautiloids.
744 The uppermost bed of the sequence is marked by the occurrence of pinnids and oyster
745 coquina. Microfacies evolve from base to top, from sandy wackestone/packstone rich in
746 echinoid remnants and small benthic foraminifers associated with calpionellids, brachiopods
747 and scarce bryozoans, to sandy mudstone/wackestone rich in echinoids and bivalves, with
748 subordinate calpionellids, planktic foraminifers, brachiopods and small benthic foraminifers.
In the northern sections, the same evolution is observed, but ammonites are abundant throughout the succession, and microfacies (Igouzoulen) are dominated by wackestone rich in echinoids and benthic foraminifers, both small sized and agglutinated. The presence of agglutinated foraminifers suggests a mild oxygen depletion of the shelf (Kuhnt et al., 1996; Kender and Kaminski, 2017).

In all sections, the top of the Be2 sequence is marked by an abrupt lithological change, locally marked by a hardground (Obbay). This sequence is interpreted as constituted by a thick retrograding succession, overlain by a thin prograding unit, deposited in a shallow outer shelf environment. The two above described sequences seem to represent the Cap Tefelney Fm of Rey et al. (1986; 1988).

### 4.3.3. Valanginian-lowermost Hauterivian mixed shelf (Figs. 10–12)

As revealed before, the Berriasian–Valanginian boundary is placed immediately above the D1 discontinuity. The identification of discontinuity surfaces allowed to identify eight transgressive-regressive sequences. Because of its condensed nature, the Obbay section will be analyzed separately.

The first sequence (Val) is a marly series that comprises scattered thin beds of limestone, belonging to the "T.". *pertransiens* StZ and *N. subtenuis* LSz. Its top has not been clearly identified in the Zalidou, Obbay and Ida w Iddar sections. It overlies the D1 discontinuity and presents a thick, thinning upward lower part overlain by a thin, thickening upper part. The calcareous lower part of the sequence contains dominantly oysters, pectinids, echinoids and ammonites. In its middle part, predominant ammonites, belemnites, terebratulids and plicatulids, and very local *Trichites* sp. (Aït Hamouch), express a deepening of the depositional environment. Deepest deposition is reached in the most marly part of the sequence where belemnites dominate. The uppermost part of the sequence is marked by a
faunal assemblage similar to that of the lower part, which indicates a shallowing trend. In Aït Hamouch, HCS and scarce vertebrate remains express a shallower environment. The top of the sequence is marked by a discrete erosional surface. In the central sections, microfacies analysis shows the predominance of mudstone to wackestone textures, and dominant echinoids and agglutinated foraminiferas in the lower and middle part of the sequence. In the upper part, wackestone textures become dominant, with abundant echinoids and bivalves, and subordinate agglutinated foraminiferas.

**The second sequence (Va2)** is a set of marlstone comprising thin limestone beds, ascribed to the lower part of the *B. campylotoxus* LSz. In the southern sections, its base (D2) is an erosional surface, while it has not been recognized in the Obbay and Ida w Idar sections. In Sidi Abderhamane, it shows a clear thinning-, then thickening-upward trend, whereas it shows a homogeneous trend in other sections. The fauna consists of ammonites, belemnites, brachiopods, plicatulids and other bivalves, suggesting an outer shelf depositional environment. In thin sections, a wackestone texture is observed, containing agglutinated foraminifers, brachiopods, echinoids and benthic foraminifers. This sequence is interpreted as deposited in an open marine, outershelf environment. In Aït Hamouch, the presence of abundant oysters and serpulids, together with echinoids and scarce corals indicates a shallower, and maybe a more mesotrophic environment. This is supported by the occurrence of sandy limestone beds showing cross bedding and HCS.

**The third sequence (Va3)** is a thin series of marlstone with thin limestone beds. Its base (D3) is an erosional surface, and ammonites ascribe to the middle part of the *B. campylotoxus* LSz. In Igouzoulen, it is reduced to a single sandy limestone bed. Where present, the lithological and faunal evolutions are comparable to that of Va2. The interpretation is, therefore, similar.

**The fourth sequence (Va4)** is only present in the southern sections, where it is dated to the upper part of the *B. campylotoxus* LSz and the *K. inostranzewi* StZ. In the southernmost
sections, it begins with a cross-bedded sandy bed that overlies surface D4. In Zalidou, the basal bed (ZA35) is a limestone bearing oysters, ammonites and plicatulids. The overlying marlstones are rich in pelagic fauna (ammonites, locally belemnites), and are themselves overlain by limestone beds rich in benthic fauna. In Zalidou, however, no limestone beds are observed in the upper part of the sequence, which is directly overlain by a thick sandstone bed (ZA40) suggesting that the upper part of the sequences has been eroded during D5. The Va4 sequence is interpreted as a new depositional sequence, the maximum depth of deposition reaching an outer shelf environment. In the Obbay section, the Va2 to Va4 sequences are highly condensed (~ 2 m), and are represented by limestone beds with thin marlstone interbeds. Limestones are slightly sandy wackestone containing predominantly phosphate- and iron-rich oolites, associated with small benthic and scarce planktic foraminifers, and few echinoid or bivalve fragments. Nuclei of oolites are frequently phosphate, glauconite or pyrite granules. These features suggest alternating high energy regime leading to condensation and oolites formation, and low energy periods allowing deposition of micrite. In some beds, partial dissolution of oolites, or local packstone texture with iron-rich micrite suggest emergence periods.

**The fifth sequence (Va5)** is a mainly marly to sandy succession, which is present in all sections and is dated early upper Valanginian (S. verrucosum StZ and N. peregrinus StSz). Its base (D5) is either an erosional surface, or a deeply karstified surface (Igouzoulen, Ida w Iddar). This basal discontinuity is directly overlain either by thick sandy beds (mainly to the north: Zalidou, Igouzoulen, Ida w Iddar), or by marlstone. The basal sandy beds contain both pelagic and benthic fauna to the south and west (Zalidou, Igouzoulen) and only benthic fauna to the north-east. The rest of the sequence shows a thinning-upward evolution, locally overlain by a thickening-upward succession. The marly part of the sequence yields a moderately deep outer shelf fauna (few ammonites and belemnites, associated with
terebratulids, serpulids and plicatulids), among which the benthic part becomes more
abundant upward.

**The sixth sequence (Va6)** is only recognized in the Obbay and Zalidou sections. It corresponds to the *O. nicklesi* StSz of the upper Valanginian. In both sections, surface D6 is overlain by a sandstone bed, but erosion is only visible in Zalidou. At the base, the benthic fauna (plicatulids, echinoids, pectinids) indicates a shallow, open marine environment. It is overlain by silty marlstone bearing belemnites, ammonites, serpulids, with some plicatulids and terebratulids, of outer shelf environment. The middle part of the sequence is rich in pyrite (pyritized ammonites in Obbay). In Zalidou, the upper part is a thickening upward succession of silty marlstone and sandstone beds with ammonites and benthic fauna, expressing a shallowing-upward trend. In Obbay, the reduced thickness and the lack of this thickening upward succession suggest an erosion period during the overlying D7 discontinuity. This is supported by the lack of the *O. nicklesi* StSz in most sections, and suggests that major subaerial erosion occurred during discontinuity D7.

**The seventh sequence (Va7)** is present in all sections and its ammonite fauna indicates the uppermost Valanginian (*C. furcillata* StSz and *T. callidiscum* StSz). It consists of a mainly marly to sandy succession that overlies an erosional surface (D7). In most sections, D6 and D7 are merged. This basal discontinuity is directly overlain by a sandy bed containing an abundant open marine fauna, among which pectinids, plicatulids and echinoids indicate a shallow environment. This is supported by the local occurrence of wood and leave fragments (Sidi Abderhamane) and probable evaporite pseudomorphs (Ida w Iddar). The middle part of the sequence bears a deep outer shelf fauna (belemnites, ammonites, plicatulids, terebratulids). In the southern sections, no thickening-upward evolution is observed in the upper part of the sequence, whereas the northeastern sections (Zalidou, Ida w Iddar) display clearly the progradation of a clastic system. In the upper part of the sequence, the southern
849

sections display an outer shelf fauna (plicatulids, belemnites, terebratulids, ammonites), while
the Ida w Iddar section is marked by very shallow sedimentary features (HCS, ripple marks,
tidal laminations).

850

851

852

Only the lower part of the eighth sequence (Ha1) has been studied. In spite of scarce
ammonite fauna, discontinuity D8 seems to roughly coincide with the Valanginian-
Hauterivian boundary, since ammonites of the *A. radiatus* StZ are found above (Aït
Hamouch, Zaouia Sidi Abderhamane), or immediately below (Zalidou) the surface D8. Ha1
begins with a sandy bed in the southern sections (Aït Hamouch, Sidi Aberhamane), or with
sandy marlstone in the northern sections. The rest of the studied succession shows a tinning-
upward trend and a scarce outer shelf to pelagic fauna.

853

854

855

856

857

858

859

860

## 4.4. Carbon isotope stratigraphy

861

The measured δ¹³Ccarb values range between -2.8 and +1 (avg. -0.8 ‰) at Zalidou, -3.3 and
+0.4 (avg. -1.5 ‰) at Aït Hamouch, -3.2 and -0.1 (avg. -1.3 ‰) at Zaouia Sidi Abderahmane,
-4 and -0.8 (avg. -1.8 ‰) at Igouzoulen, and -4.7 and -0.2 (avg. -1.8 ‰) at Ida w Iddar (Figs.
3–7). The δ¹³Ccarb values of sections are provided in Appendix F (Supplementary material).
Among the studied sections in the EAB, Zalidou (Fig. 3) presents the highest sampling
resolution and is considered as the reference section for the δ¹³Ccarb. The Weissert Event is
identified from the base of the CIE, until its climax, following the formal definition of Erba et
al. (2004). According to this definition, the CIE is observed at Zalidou from the basal part of
*K. inostranzewi* StZ (16.25 m) to the upper part of *O. nicklesi* StSz, in which the climax is
recorded at 32.8 m (upper NK3A to upper NK3B and upper CC3b to upper CC4a calcareous
nannofossil subzones). Below this peak, there is a short-lived plateau of values comprised
between 0 and 1 ‰ (dated from the *O. nicklesi* StSz); above the climax, the isotopic curve is
characterized by a slow decrease in values (uppermost *O. nicklesi* StSz and *C. furcillata* StZ).

862

863

864

865

866

867

868

869

870

871

872

873
The top of the Weissert Event is recorded just below the LO of the nannofossil biomarker *T. verenae*, marking the base of the nannofossil Zone NC4. At Aït Hamouch (Fig. 4), the CIE is cautiously identified from 32.8 (*K. inostranzewi* StZ) to ~36 m (middle part of *N. peregrinus* StZ). In this section, *S. verrucosum* StZ was not recognized separately (see AH89 and comments on ammonite biostratigraphy). Additionally, the *N. peregrinus* StZ is reduced (~ 7 m) compared with Zalidou (~ 14 m), and the *O. nicklesi* StSz was not recognized. This can be also observed from the reduced NK3B calcareous nannofossil Subzone in Aït Hamouch (1.2 m) compared with Zalidou (12.8 m). The slow decrease of $\delta^{13}C_{carb}$ values in the *C. furcillata* StZ is recorded. At Zaouia Sidi Abderahmane (Fig. 5), the CIE starts in the upper part of the *K. inostranzewi* StZ (~ 30 m) and the climax value is recorded in the *N. peregrinus* StZ (~ 34.5 m). After this peak, the decrease of the values is mainly observed in the *C. furcillata* StZ.

Again, the plateau phase of positive $\delta^{13}C_{carb}$ values is not recognized before the climax. At Igouzoulen (Fig. 6), it is difficult to recognize the CIE; it could be placed between 36 and 40 m (*K. inostranzewi* StZ and *S. verrucosum* StZ). At Ida w Iddar (Fig. 7), the CIE could be placed between 12 and 16 m (*K. inostranzewi* StZ and *N. peregrinus* StZ). It should be noted that the *C. furcillata* StZ is also characterized by a smooth decrease of $\delta^{13}C_{carb}$ values. To summarize, the plateau phase of positive $\delta^{13}C_{carb}$ values below the climax is only recognized in the Zalidou section and is dated to the *O. nicklesi* StSz. This interval may be missing in the other sections due to a strong erosion expressed by the sedimentary discontinuities (D6-D7 merged; Figs. 4–5, 7).

## 5. Discussion

The detailed zonations based on ammonite and calcareous nannofossil data allow to date accurately the significant changes in $\delta^{13}C_{carb}$ values and to ascribe an age for the sedimentary discontinuities observed in the EAB. This integrated zonal scheme supports detailed
correlations of these events with those recorded in other basins of the northern Tethyan margin, for which integrated stratigraphic studies were also made. In the following parts, comparisons are mainly proposed with SE France and occasionally with other areas.

## 5.1. Inter-basin correlation of carbon isotopic events

The Weissert Event recorded in the EAB is here compared with carbon isotope data available in SE France, only if constrained by ammonite and nannofossil biostratigraphy (Hennig et al., 1999; Duchamp-Alphonse et al., 2007; McArthur et al., 2007; Gréselle et al., 2011; Kujau et al., 2012; Martinez et al., 2013; 2015; Gollain et al., 2019). For the "T." *pertransiens* StZ and the lower part of the *N. neocomiensiformis* StZ, the carbon isotope data of the Angles section (Valanginian hypostratotype, SE France; Duchamp-Alphonse et al., 2007) were added on the Vergol-La Charce composite section representing the Vocontian Basin succession (Fig. 13).
This part of the curve (dashed line) must be interpreted carefully as it is challenging to establish correlations between the Vergol-La Charce and Angles sections. The log of the Angles section given by Duchamp-Alphonse et al. (2007) is not detailed, and the lower Valanginian ammonite zonal scheme was not improved since Busnardo and Thieuloy (1979; see Bulot and Thieuloy, 1995).

A slight decrease in δ¹³Ccarb values (around -0.5 ‰) is observed from the lower part of "T." *pertransiens* StZ to the lower part of *N. neocomiensiformis* StZ; an increase of a same order is recorded in the upper part of this zone. A similar trend (with a stronger amplitude, around +/- 1 ‰) is recorded in some sections of the EAB as Ait Hamouch and Zaouia Sidi Abderahmane (Figs. 4–5). In SE France (Gréselle et al., 2011; Martinez et al., 2015; Gollain et al., 2019; Fig. 13) and SE Spain (Aguado et al., 2018), detailed biostratigraphic data show that the onset of the CIE occurs in the *K. inostranzewi* StZ, more precisely below the boundary between *K. inostranzewi* StSz and *N. platycostatus* StSz (lowest values of δ¹³C; 0.14‰ and 0.1‰, respectively). In the *K. inostranzewi* StSz, the pre-CIE δ¹³C curve shows oscillations between
0.4‰ and 1‰. In the Vocontian Basin, the basal part of this subzone is characterized by four organic-matter-rich layers (Barrande layers; Reboulet et al., 2003) that are not observed in the studied Moroccan area. In some sections of the EAB, low δ¹³Ccarb values are recorded in the *K. inostranzewi* StZ and were interpreted as the onset of the CIE (Aït Hamouch and Zaouia Sidi Abderahmane; Figs. 4–5). At Zalidou, two negative peaks are observed in the *K. inostranzewi* StZ (Figs. 3, 13). The first one (-2.7‰), located at the base, is followed by an increase of isotopic values that continues until the lower part of the *N. peregrinus* StZ. A single point, located at the top of the *K. inostranzewi* StZ, is clearly outside of this curve trend. As it is the lowest value recorded in the Zalidou section (-2.8‰), this might correspond to the onset of the CIE. This would be in agreement with observations made on the Aït Hamouch and Zaouia Sidi Abderahmane sections, for which the CIE starts in the interval between discontinuities D4 and D5 (Figs. 4–5). However, as the onset of the CIE occurs only few meters above the SB F defined by Gréselle and Pittet (2010) in the Vocontian Basin (Fig. 13), the isotopic event may start with D4 (or close to this discontinuity) at Zalidou. As a matter of fact, part of the time recorded by deposits in the deep Vocontian Basin is most probably lacking in the EAB, where D4 corresponds to a major emergence surface, on which sedimentation resumed later than in the Vocontian Basin. This interpretation is consistent with the calcareous nannofossils data at Aït Hamouch and Zalidou, which show that the beginning of the Weissert Event is characterized by the FO of *H. circumradiatus* and by a decrease in the nannoplankton production (Shmeit et al., 2022). Consequently, the onset of the CIE at Zalidou may be placed at the first negative shift in δ¹³Ccarb values (-2.7‰), i.e. at the base of the *K. inostranzewi* StZ (Fig. 3). Diagenetic impacts on platform carbonates during emergence periods and meteoritic diagenesis (Godet et al., 2016) may explain the strong negative values observed just below D5 at Zalidou (δ¹³Ccarb = -2.8‰), as well as immediately below D8 at Aït Hamouch (δ¹³Ccarb = -5.9‰; Fig. 13).
In the Vocontian Basin, the maximum of δ¹³Ccarb values is recorded in the *S. verrucosum* StZ (double peaks in the *S. verrucosum* StSz; Duchamp-Alphonse et al., 2007; McArthur et al. 2007; Kujau et al., 2012; Martinez et al., 2015; Gollain et al., 2019). This trend in the isotopic curve is not recorded in the EAB. It can be partly explained by condensed intervals and/or stratigraphic gaps around the lower–upper Valanginian boundary; the *S. verrucosum* StZ was partly (Zalidou, Zaouia Sidi Abderahamane) or not (Ait Hamouch; see AH89 and comments on ammonite biostratigraphy) recognized. In these Moroccan sections, the maximal values are observed in the *N. peregrinus* StZ and may correspond to the plateau of high values recorded in the *N. peregrinus* StZ in SE France (Martinez et al., 2015; Fig. 13) and SE Spain (Aguado et al., 2018). In both latter areas, as in the EAB, the carbon isotope curve is characterized by a slow decrease of δ¹³Ccarb values that starts in the uppermost part of the *N. peregrinus* StZ (Ait Hamouch and Zaouia Sidi Abderrahmane), more precisely at the top part of the *O. nicklesi* StSz (Zalidou), and continues in the *C. furcillata* StZ (Zalidou, Ait Hamouch, Zaouia Sidi Abderrahmane, and Ida w Iddar sections; Figs. 3–5, 7). Thus, except for the interval corresponding to the *S. verrucosum* StZ, the main trends of the Valanginian carbon isotope curve in the northern Tethyan basins are similarly observed in the EAB.

965

## 5.2. Inter-basin correlation of discontinuities

The EAB is correlated mainly with the SE France Basin, for which biostratigraphic, isotopic and sedimentologic data are all available and a platform-basin transect for the Valanginian depositional system was already established (Arnaud et al., 1981; Reboulet, 1996; Gréselle and Pittet, 2010 and references therein). Thus, the French and Moroccan basins are relevant areas to illustrate the North and South Tethyan margins, respectively.

In the northern Vocontian Basin, Gréselle and Pittet (2010) identified five major sequence boundaries in the Valanginian succession. Their discontinuity “D”, at the Berriasian–
974 Valanginian boundary (lowermost part of the "T." *pertransiens StZ sensu* Kenjo et al., 2021),
975 corresponds to our SB D1. This discontinuity seems largely identified in SE France, since a
976 basal Valanginian discontinuity (between their "*Thurmanniceras*" *otopeta* (sub-)zone and
977 "*T."* *pertansiens* ammonite zone) has been identified in the Subalpine chain by Arnaud et al.
978 (1981; their D-VI) and Morales et al. (2013; their SBe), and in the Provence Platform (DCB
979 of Bulot et al., 1995; 1997). Like in the EAB, these surfaces separate the underlying carbonate
980 shelf from overlying marlstone and limestone, locally sandy. Discontinuity "E" (Gréselle and
981 Pittet, 2010), ascribed to the lower part of the *N. neocomiensiformis* StZ, likely correlates with
982 D-VII of Arnaud et al. (1981), SBf of Morales et al. (2013) and D2 of this work.
983 Discontinuity D3 of the EAB, ascribed to the upper part of the *N. neocomiensiformis* StZ
984 (middle part of the *B. campylotoxus* LSz) may be correlated with the minor discontinuity
985 placed by Gréselle and Pittet (2010, their fig. 14) between their V4 and V5 sequences.
986 In SE France, the interval around the lower-upper Valanginian boundary is marked by two
987 successive discontinuities: D-VIII and D-IX of Arnaud et al. (1981). According to their
988 correlations with the Angles section (fig. 6 of Arnaud et al., 1981) and according to the
989 standard zonation used here in the Vocontian Basin composite section (Fig. 13), D-VIII and
990 D-IX may correspond to the basal (SB F) and top discontinuities of sequence V6 in Gréselle
991 and Pittet (2010), ascribed to the basal parts of the *K. inostranzewi* StZ and *S. verrucosum*
992 StZ, respectively. According to Bulot (1995, p. 246; see also Bulot et al., 1997), the mid-
993 Valanginian discontinuity of Masse and Lesbros (1987; "discontinuité médiovalanginienne")
994 and the discontinuity of the middle Valanginian (DVM *sensu* Autran, 1993), dated to the
995 basal and top parts of the *K. inostranzewi* zone, respectively, are distinct, contrary to the
996 suggestion of Autran (1993), who correlated them. This discrepancy in interpretations may be
997 due to the very shallow depositional environments at that time, and correlative emergence
998 periods, subsequent erosion and/or amalgamation of discontinuity surfaces (Arnaud et al.,
1999 1981; Masse and Lesbros, 1987; Autran, 1993; Bulot, 1995; Bulot et al., 1995; 1997; 2010; Gréselle and Pittet, 2010; Morales et al., 2013), as observed in the Moroccan studied area. In the EAB, as D4 is ascribed to the *K. inostranzewi* StZ in the Zalidou (Fig. 13), Zaouia Sidi Abderahmane and Obbay sections, this discontinuity may be correlated with D-VIII of Arnaud et al. (1981) and with discontinuity "F" of Gréselle and Pittet (2010). In both areas, this discontinuity marks a major facies change, corresponds to the shallowest part of the succession and is unconformable onto previous deposits. D4 may correspond to the "discontinuité médiovalanginienne" of Masse and Lesbros (1987). As observed in the Aït Hamouch and Zaouia Sidi Abderahmane sections (see previous explanations for Zalidou) and in SE France (Vocontian Basin and Provence Platform; Fig. 13), D4 and SB F, respectively, are followed by a negative shift in δ¹³Ccarb values corresponding to the onset of the CIE.
1010 Discontinuity D5 caps a depositional sequence that onlaps onto the D4 major discontinuity and thus wedges out eastward (Fig. 12), while D4 is merged with D5 in the Igouzoulen and Ida w Iddar sections of the EAB (Fig. 11). D5 is identified at the lower-upper Valanginian boundary (*K. inostranzewi* StZ–*S. verrucosum* StZ boundary) in the Zalidou, Ida w Iddar and Obbay sections (Figs. 3, 7–8); this discontinuity is ascribed to the basal part of the *S. verrucosum* StZ at Zaouia Sidi Abderahmane and Igouzoulen (Figs. 5–6). Therefore, D5 should be correlated with D-IX of Arnaud et al. (1981), the DVM of Autran (1993) and with the minor SB that separates V6 and V7 sequences of Gréselle and Pittet (2010).
1011 In the EAB, where overlain by the Va6 sequence, D6 occurred in the top part of the *N. peregrinus* StSz at Zalidou and Obbay sections (Figs. 3, 8), where the *O. nicklesi* StSz was recognized. In successions of the Vocontian Basin, Reboulet et al. (1992) mentioned a SB that underlines Lowstand deposits ("Faisceau median" or "Peregrinus bundle", La Charce section) dated to the *N. peregrinus* StSz (Reboulet and Atrops, 1999), while Gréselle and Pittet (2010)
identified their discontinuity G also in the lower part of the same (Sub-)zone. Therefore, these
events likely correlate with the D6 of the EAB (Fig. 13).

In SE France, Autran (1993) identified a major discontinuity in the upper Valanginian,
namely the upper Valanginian discontinuity (DVS), ascribed by this author to the former *H. trinodosum* Zone (equivalent to the *O. nicklesi* StSz and *C. furcillata* StSz). According to biostratigraphic data provided by Reboulet (1996), the DVS occurs at the *N. peregrinus* StZ-*C. furcillata* StZ boundary. Consequently, this discontinuity may be correlated with our D7 since the latter is also situated between these standard zones (Zalidou and Obbay sections).

The D7 is responsible for the partial or total erosion of our Va6 depositional sequence and is frequently merged with D6 (Figs. 9–10). Consistently, the DVS is associated in SE France with erosions that may remove down to the middle Valanginian discontinuity sensu Autran (1993; DVM). Studying basinal successions, Reboulet et al. (1992) defined a SB discontinuity at the base of thick Lowstand deposits (Furcillata calcareous bundle in Fig. 13) encompassing the upper part of the *O. nicklesi* StSz and the lower part of the *C. furcillata* StSz. Since there are probably no Lowstand deposits in the EAB, the SB of Reboulet et al. (1992) likely correlates with the D7 of the EAB. It also correlates with discontinuity H of Gréselle and Pittet (2010), placed at the top of the *O. nicklesi* StSz. Nevertheless, the latter authors interpret the D5–D7 interval as a period of sea level fall following a major transgression, whereas we interpret the same interval in the EAB as a transgressive–regressive cycle, the maximum flooding of which is placed in the *O. nicklesi* StSz.

In the EAB, D8 is placed at the Valanginian–Hauterivian boundary (Aït Hamouch and Zaouia Sidi Abderahmane; Figs. 4–5) or in the lowermost part of the lower Hauterivian *A. radiatus* StZ (Zalidou, Fig. 3). This discontinuity corresponds to a strong regression. It correlates, in SE France (Fig. 13), with the major surface D-X of Arnaud et al. (1981), with the base of Lowstand deposits of Reboulet et al. (1992), with the top of the V12 sequence of Gréselle and
1048 Pittet (2010), and with the uppermost Valanginian discontinuity (DVT of Bulot et al., 2010; see also Reboulet, 1996, p. 275). In SE France, this discontinuity corresponds to a hiatus in shelf areas and may comprise several surfaces (Bulot et al., 2010).

1051

1052 **5.3. Sea level changes and sequence origin**

1053 The comparisons exposed above show that most of the discontinuities identified in the EAB are also known elsewhere, especially in SE France. This strongly suggests that eustacy controlled the evolution of both areas. Following the two Berriasian sequences, which express a transgressive trend with respect to the base of the sections, the Valanginian succession can be divided into three main transgressive-regressive cycles, divided by the main discontinuities D4 and D7 (Fig. 12). The first one includes Va1 to Va3, the second one comprises Va4 to Va6, and the third one is made of the Va7 sequence. The maximum flooding of the first cycle occurred during the lower part of the *N. neocomiensiformis* Stz, namely the *N. subtenuis* LSz; the maximum depositional depth of the second cycle seems to be reached in the *O. nicklesi* StSz, and a third maximum flooding is reached during the *C. furcillata* StSz.

1063

1064 The Va2 and Va3 sequences encompass a period of low sea level (Haq, 2014), which culminates with the major D4 discontinuity. The latter is marked by deeply karstified surfaces amalgamating several discontinuities in the proximal northern sections and is overlain by the Va4 sequence that onlaps toward the north or northeast. In the southern part of the EAB, the “mid-Valanginian events” of Masse and Lesbros (1987) are represented by at least three discontinuities, materialized by erosional surfaces in the southern sections. These discontinuities bound depositional sequences marked by an open marine fauna indicating an outer shelf environment, which suggests that sea level oscillations were of high amplitude.

1065

1066

1067

1068

1069

1070

1071

1072 Moreover, in the Aït Hamouch section, the Va2, Va3, and part of the Va4 sequences belong to
1073 the *B. campylotoxus* LSz. According to Martinez et al. (2013), the duration of the *B. campylotoxus* subzone is estimated at 390 ky. Since their work, the conception of some zones
1074 or sub-zones has changed for the upper part of the lower Valanginian with the introduction of
1075 the *N. neocomiensiformis* StZ and *K. inostranzewi* StZ (Reboulet et al., 2014, p. 128–129 and
1076 tab. 2). Accordingly, the conception of the *B. campylotoxus* LSz used in the EAB sections
1077 would correspond to a larger stratigraphic interval in the Vergol section (Vocontian Basin)
1078 than considered in the work of Martinez et al. (2013). Consequently, the duration of the
1079 Moroccan *B. campylotoxus* LSz would be higher than 390 ky and may be estimated at around
1080 570 ky. This means that the average duration of the sequences identified in the Aït Hamouch
1081 section is around 200 ky. Although not conclusive, these observations are consistent with an
1082 orbitally-driven, glacio-eustatic origin for these rapid and high amplitude sea level
1083 fluctuations, as suggested for the “middle Valanginian” (Price, 1999; Gréselle and Pitet, 2010;
1084 Martinez et al., 2013; Charbonnier et al., 2020).
1085

1086 As a whole, the second and third cycles present deeper depositional environments than the
1087 first one, expressing a rise in sea level, likely responsible for the drowning of the lower
1088 Valanginian carbonate shelf in the EAB, as well as around the world (Föllmi, 2012).

1089 Additionally, the upper Valanginian deposits are more clayey than the lower Valanginian first
1090 cycle, suggesting an increase of terrigenous supply. Such change has been observed elsewhere
1091 in the world, and interpreted as a change toward more humid conditions (e.g., Schlager, 1980;
1092 Bulot et al., 1997; Föllmi, 2012; Bottini et al., 2018).

1093 In SE France, Masse and Lesbros (1987) noted that what they call the “mid-Valanginian
events” are associated with a sharp deepening of the depositional environments and with the
1094 development of gravitationally reworked sediments, as well as significant terrigenous input
1095 (Duchamp-Alphonse et al., 2007). They propose, therefore, that the area was submitted to
1096 tectonic movements of the basement (Masse and Lesbros, 1987; Bulot et al., 1997). A partly
1097
1098 tectonic origin has also been suggested for the major discontinuity observed around the lower-upper Valanginian boundary in Argentina (Schwarz and Buatois, 2012), and although less accurately dated, in Romania (Gradinaru et al., 2016), and Sardinia (Bottini et al., 2018).
1099
1100 In the EAB, neither synsedimentary deformation features nor sharp subsidence changes have been observed around the lower-upper Valanginian boundary. However, as in SE France, the upper Valanginian deposits are marked by a significantly higher amount of terrigenous sediments (sand and silt), especially in the northeastern sections (Fig. 12). This may indicate an erosion resumption in the present-day High Atlas, which may have been triggered by tectonic movements. Nevertheless, since most of the discontinuities identified in the EAB are also known in other areas of the world, these possible tectonic movements were mild enough not to disturb the eustatic signal.
1101
1102
1103
1104
1105
1106
1107
1108
1109

## 6. Conclusion

1110
1111 The integrated study (ammonites, calcareous nannofossils, sedimentology, sequence stratigraphy, carbon isotopes) of the upper Berriasian-lowermost Hauterivian interval along six sections (Zalidou, Aït Hamouch, Zaouia Sidi Abderahmane, Igouzoulen, Ida w Iddar and Obbay) located in the Essaouira-Agadir Basin (Morocco, South Tethyan margin) led to the following major results.
1112
1113
1114
1115

1116
1117
1118
1119
1120
1121
1122 1. A systematic revision of the whole ammonite fauna was made and the stratigraphic distributions of taxa are given for all studied sections. The analysis of their ranges allowed the establishment of a detailed zonal scheme, more particularly for the lower Valanginian. It corresponds to the standard zonation (Reboulet et al., 2018) for the Mediterranean Province of the Mediterranean-Caucasian Subrealm (Tethyan Realm). Two local subzones were added in the *Neocomites neocomiensiformis* Standard Zone, which is recognized for the first time in the Moroccan lower Valanginian successions. The base of the Valanginian and that of the
1123 upper Valanginian are placed at the base of the "*Thurmanniceras*" pertransiens Standard
1124 Zone and that of *Saynoceras verrucosum* Standard Zone, respectively.

1125 2. A calcareous nannofossil biostratigraphy was established in the most suitable sections
1126 (Zalidou and Aït Hamouch) for nannofossil studies (Shmeit et al., 2022; this work). The
1127 calcareous nannofossil zonal schemes of Sissingh (1977) and Bralower et al. (1995) are
1128 recognized, and a sequence of seven nannofossil bioevents is identified. Thus, ammonite and
1129 nannofossil zonations are calibrated for these reference sections.

1130 3. Detailed sedimentological field and microfacies analysis, led to recognize sedimentary
1131 discontinuities (D0 to D8), which allowed a sequence stratigraphic analysis of the basin. Two
1132 depositional sequences are recognized in the Berriasian (Be1 and Be2), seven in the
1133 Valanginian (Va1 to Va7) and one in the Hauterivian (Ha1). Major discontinuities resulted in
1134 significant erosions that led locally to amalgamated surfaces, at the lower-upper Valanginian
1135 boundary interval (D4-D5) and in the middle part of the upper Valanginian (D6-D7).

1136 4. Carbon isotope analyses were made in five sections. The Weissert Event is well recorded in
1137 the highest resolution δ¹³Cₚcarb curve obtained in this study (Zalidou). The mid-Valanginian
1138 carbon isotope excursion is also relatively well observed at Aït Hamouch and Zaouia Sidi
1139 Abderahmane, but more cautiously interpreted elsewhere. The precise age of its onset is
1140 obscured by the major "mid-Valanginian" eustatic regression that led to a widespread
1141 emergence, erosions, and sedimentary hiatuses (D4-D5).

1142 5. The Valanginian carbon isotope record observed in the Essaouira-Agadir Basin is similar to
1143 those recorded in the south-east France Basin. The Moroccan sedimentary discontinuities can
1144 be correlated with those identified in south-east France, suggesting that eustacy mainly
1145 controlled the evolution of both depositional areas.

1146

1147
1148 Acknowledgements

1149 Our project on the Essaouira-Agadir Basin benefited of financial supports from a project

1150 (2013–2015) funded by the Moroccan and French Ministries of foreign affairs (Partenariat

1151 Hubert Curien, Volubilis n° 031/STU/13), from the French IRD, Campus France, and various

1152 grants from ISTerre, the Laboratoire de Géologie de Lyon, the OSUG@2020 Labex, the

1153 CNRS SYSTER program and IODP France soutien post-cruise. Christophe Despierres

1154 (Grenoble) and Thomas Letulle (Lyon) are thanked for their contribution to this study through

1155 Master memoirs. We acknowledge Emmanuel Robert (University of Lyon) for help in

1156 completing the macrofossil sampling in some sections. We are indebted to Mohssine

1157 Ettachfini (University of Marrakech, Morocco), who gave full access to his ammonite

1158 collections and made helpful suggestions. We are extremely grateful to Miguel Company

1159 (University of Granada, Spain) for fruitful discussions on ammonites. We are grateful to the

1160 editor Eduardo Koutsoukos, Beatriz Aguirre-Urreta and an anonymous reviewer for both

1161 corrections and comments which greatly improved the quality of an earlier version of the

1162 manuscript.

1163

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1479 Cretaceous Ammonite Working Group, the "Kilian Group" (Vienna, Austria, 15th April

1480 2008). Cretaceous Research 30, 496-502.

1481 Reboulet, S., Mattioli, E., Pittet, B., Baudin, F., Olivero, D., Proux, O., 2003. Ammonoid and

1482 nannoplankton abundance in Valanginian (early Cretaceous) limestone-marl successions

1483 from the southeast France Basin: carbonate dilution or productivity? Palaeogeography,

1484 Palaeoclimatology, Palaeoecology 201, 113-139.

1485 Reboulet, S., Rawson, P.F., Moreno-Bedmar, J.A. (reporters), Aguirre-Urreta, M.B.,

1486 Barragán, R., Bogomolov, Y., Company, M., González-Arreola, C., Idakieva Stoyanova,

1487 V., Lukeneder, A., Matrion, B., Mitta, V., Randrianaly, H., Vašíček, Z., Baraboshkin, E.J.,

1488 Bert, D., Bersac, S., Bogdanova, T.N., Bulot, L.G., Latil, J.-L., Mikhailova, I.A., Ropolo,

1489 P., Szives, O., 2011. Report on the 4th International Meeting of the IUGS Lower
1490 Cretaceous Ammonite Working Group, the "Kilian Group" (Dijon, France, 30th August
1491 2010). Cretaceous Research 32, 786-793.

1492 Reboulet, S., Szives, O. (reporters), Aguirre-Urreta, B., Barragán, R., Company, M., Frau, C.,
1493 Kakabadze, M.V., Klein, J., Moreno-Bedmar, J.A., Lukeneder, A., Pictet, P., Ploch, I.,
1494 Raisossadat, S.N., Vašíček, Z., Baraboshkin, E.J., Mitta, V.V., 2018. Report on the 6th
1495 International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the
1496 Kilian Group (Vienna, Austria, 20th August 2017). Cretaceous Research 91, 100-110.

1497 Reboulet, S., Szives, O. (reporters), Aguirre-Urreta, B., Barragán, R., Company, M., Idakieva,
1498 V., Ivanov, M., Kakabadze, M.V., Moreno-Bedmar, J.A., Sandoval, J., Baraboshkin, E.J.,
1499 Çağlar, M.K., Főzy, I., González-Arreola, C., Kenjo, S., Lukeneder, A., Raisossadat, S.N.,
1500 Rawson, P.F., Tavera, J.M., 2014. Report of the 5th International Meeting of the IUGS
1501 Lower Cretaceous Ammonite Working Group, the Kilian Group (Ankara, Turkey, 31st
1502 August 2013). Cretaceous Research 50, 126-137.

1503 Rey, J., Canérot, J., Peybernès, B., Taj-Eddine, K., Rahhali, I., Thieuloy, J-P. 1986. Le
1504 Crétacé inférieur de la région d'Essaouira : données biostratigraphiques et évolutions
1505 sédimentaires. PICG - UNESCO section Sciences de la Terre 183, Revue de la Faculté des
1506 sciences de Marrakech, numéro spécial 2, 413-441.

1507 Rey, J., Canérot, J., Peybernès, B., Taj-Eddine, K., Thieuloy, J.-P., 1988. Lithostratigraphy,
1508 biostratigraphy and sedimentary dynamics of the Lower Cretaceous deposits on the
1509 northern side of the western High Atlas (Morocco). Cretaceous Research 9, 141-158.

1510 Roch, E., 1930. Une histoire stratigraphique du Maroc. Notes et Mémoires du Service
1511 géologique du Maroc 80, 440 pp.

1512 Roth, P.H., 1978. Cretaceous Nannoplankton Biostratigraphy and Oceanography of the
1513 Northwestern Atlantic Ocean. In: Benson, W. E., Sheridan, R. E., Pastouret, L., Enos, P.,
1514 Freeman, T., Murdmaa, I. O., Worstell, P. (editor), Gradstein, F., Schmidt, R. R., Weaver,

1515 F. M., Stuermer, D. H., Initial reports of the Deep Sea Drilling Project 44, 731–759.

1516 Schlager, W., 1980. Mesozoic calciturbidites in Deep Sea Drilling Project Hole 416A:

1517 Recognition of a drowned carbonate platform. In: Lancelot, Y., Winterer, E.L. (eds): Initial

1518 Reports of the Deep Sea Drilling Project, 50, Washington D.C., U.S. Gov. Print. Off., 733–

1519 749.

1520 Schwarz, E., Buatois, L.A., 2012. Substrate-controlled ichnofacies along a marine sequence

1521 boundary: The Intra-Valanginian Discontinuity in central Neuquén Basin (Argentina).

1522 Sedimentary Geology 277–278, 72–87.

1523 Shmeit, M., Giraud, F., Jaillard, E., Reboulet, S., Masrour, M., Spangenberg, J.E., El-

1524 Samrani, A., 2022. The Valanginian Weissert Event on the south Tethyan margin: A

1525 dynamic paleoceanographic evolution based on the study of calcareous nannofossils.

1526 Marine Micropaleontology 175, 102134.

1527 Sissingh, W., 1977. Biostratigraphy of Cretaceous Calcareous Nannoplankton. Geology en

1528 Mijnbouw 56, 37–65.

1529 Soua, M., 2016. Cretaceous oceanic anoxic events (OAEs) recorded in the northern margin of

1530 Africa as possible oil and gas shale potential in Tunisia: An overview. International

1531 Geology Review 58, 277-320.

1532 Sprovieri, M., Coccioni, R., Lirer, F., Pelosi, N., Lozar, F., 2006. Orbital tuning of a lower

1533 Cretaceous composite record (Maiolica Formation, central Italy). Paleooceanography 21,

1534 PA4212.

1535 Taj-Eddine, K., Ettachfini, El M., Rey J., 1992. Le Berriasien et le Valanginien de l'Atlas

1536 Atlantique - Maroc. Biostratigraphie et séquences de dépôt. Géologie Méditerranéenne 19,

1537 41–50.
1538 Thieuloy, J.P., 1977. La zone à Callidiscus du Valanginien supérieur vocontien (Sud-Est de la France). Lithostratigraphie, ammonitofaune, limite Valanginien-Hauterivien, corrélations.
1539
1540 Géologie Alpine 53, 83-143.

1541 Thieuloy, J.P., Bulot, L., 1992. Ammonites du Crétacé inférieur du Sud-Est de la France : 1.
1542 Nouvelles espèces à valeur stratigraphique pour le Valanginien et l'Hauterivien. Géologie
1543 Alpine 68, 85-103.

1544 Thieuloy, J.-P., Fuhr, M., Bulot, L., 1990. Biostratigraphie du Crétacé inférieur de l'Arc de Castellane (S.E. de la France). 1 : Faunes d'ammonites du Valanginien supérieur et âge de l'horizon dit de "La Grande Lumachelle". Géologie Méditerranéenne 17, 55-99.

1547 Vašíček, Z., 2020. *Tescheniceras* gen. nov. (Ammonoidea) and the definition of the
1548 Valanginian/Hauterivian boundary in Butkov Quarry (Central Western Carpathians,
1549 Slovakia). Acta Geologica Polonica 70, 569-584.

1550 Wiedmann, J., Butt, A., Einsele, G., 1982. Cretaceous Stratigraphy, Environment, and
1551 Subsidence History at the Moroccan Continental Margin. In: von Rad, U. et al. (Eds.),
1552 Geology of the Northwest African Continental Margin, 366-395, Springer-Verlag.

1553 Wippich, M.G.E., 2001. Die tiefe Unter-Kreide (Berrias bis Unter-Hauterive) im
1554 südwestmarokkanischen Becken: Ammonitenfauna, Bio-und Sequenzstratigraphie.
1555 Unpublished PhD thesis, Universität Bochum, 142 pp.

1556 Wippich, M.G.E., 2003. Valanginian (Early Cretaceous) ammonite faunas from the western
1557 High Atlas, Morocco, and the recognition of western Mediterranean "standard" zones.
1558 Cretaceous Research 24, 357-374.

1559 Witam, O., 1998. Le Barrémien-Aptien de l'Atlas Occidental (Maroc) : lithostratigraphie,
1560 biostratigraphie, sédimentologie, stratigraphie séquentielle, géodynamique et
1561 paléontologie. Strata 30, 1-421.
1562 Zühlke, R., Bouaouda, M.-S., Ouajhain, B., Bechstädt, T., Leinfelder, R., 2004. Quantitative

1563 Meso/Cenozoic development of the eastern Central Atlantic continental Shelf, western

1564 High Atlas, Morocco. Marine and Petroleum Geology 21, 225–276.

1565

1566 **Figure captions**

1567 Figure 1. Location of the study area. A. Location of the Essaouira-Agadir Basin

1568 (EAB). B. Geological sketch of the EAB, and location of the studied sections (black

1569 squares). The east–west transect of sections illustrated in Fig. 2 is represented by

1570 a black line.

1571

1572 Figure 2. The Berriasian–lower Hauterivian sedimentary evolution in the southern part of the

1573 Essaouira-Agadir Basin. Simplified from Ferry et al. (2007). Note the eastward retrogradation

1574 of facies during the Berriasian–upper Valanginian interval, and the westward progradation in

1575 the lower Hauterivian. Among the successions illustrated here, only Aït Hamouch was

1576 selected for the present work.

1577

1578 Figure 3. The Zalidou section. Stratigraphic distribution of macrofauna (mainly ammonites; a

1579 question mark is added when identification is doubtful) and ammonite zonation (standard and

1580 local units); layers of sampling are indicated at the right of the succession. Nannofossil

1581 zonation (NK, NC and CC) and bioevents (FO and LO) from Shmeit et al. (2022) and

1582 completed in this work. The NK and NC zones are from Bralower (1987), Bralower et al.

1583 (1989; 1995), modified from Roth (1978). The CC zones and subzones are from Sissingh

1584 (1977), modified by Perch-Nielsen (1979; 1985) and Applegate and Bergen (1988).
1585 Sedimentary discontinuities (D). Carbon isotopic curve; layers of sampling are indicated at the left of the succession. The lower-upper Valanginian boundary is preferentially placed at the base of layers ZA40 (boundary indicated by a solid line); an alternative proposal (ZA36, boundary indicated by a dashed line) is discussed in the text (see 4.1. Ammonite stratigraphy).

1589

1590 Figure 4. The Aït Hamouch section (two outcrops). Stratigraphic distribution of macrofauna (mainly ammonites; a question mark is added when identification is doubtful) and ammonite zonation (standard and local units); layers of sampling are indicated at the right of the succession. Nannofossil zonation (NK, NC and CC) and bioevents (FO and LO) from Shmeit et al. (2022) and completed in this work. Sedimentary discontinuities (D). Carbon isotopic curve; layers of sampling are indicated at the left of the succession. The alphanumeric notation is “AH”, except for the interval between 32 and 50.5 m of the right-hand column where “AtH” is used (AtH1 to AtH18).

1598

1599 Figure 5. The Zaouia Sidi Abderahmane section (two outcrops). Stratigraphic distribution of macrofauna (mainly ammonites; a question mark is added when identification is doubtful) and ammonite zonation (standard and local units); layers of sampling are indicated at the right of the succession. Sedimentary discontinuities (D). Carbon isotopic curve; layers of sampling are indicated at the left of the succession.

1604

1605 Figure 6. The Igouzoulen section. Stratigraphic distribution of macrofauna (mainly ammonites; a question mark is added when identification is doubtful) and ammonite zonation (standard and local units); layers of sampling are indicated at the right of the succession.
1606
1607 Sedimentary discontinuities (D). Carbon isotopic curve; layers of sampling are indicated at
1609 the left of the succession. The alphanumeric notation is “IGz”, except in the basal part of the
1610 section (between 12 and 16.3 m) where “IGb” is used.

1611
1612 Figure 7. The Ida w Iddar section. Stratigraphic distribution of macrofauna (mainly
1613 ammonites; a question mark is added when identification is doubtful) and ammonite zonation
1614 (standard and local units); layers of sampling are indicated at the right of the succession.
1615 Sedimentary discontinuities (D). Carbon isotopic curve; layers of sampling are indicated at
1616 the left of the succession.

1617
1618 Figure 8. The Obbay section. Stratigraphic distribution of macrofauna (mainly ammonites; a
1619 question mark is added when identification is doubtful) and ammonite zonation (standard and
1620 local units); layers of sampling are indicated at the right of the succession. Sedimentary
1621 discontinuities (D).

1622
1623 Figure 9. Calcareous nannofossil events and zonation calibrated with the ammonite standard
1624 zonation of the Essaouira-Agadir Basin (this study) and their comparisons with existing
1625 Tethyan biozonal schemes where both ammonite and nannofossil records are also available:
1626 South-east France modified from Bergen (1994); Vergol-La Charce composite section
1627 (Vocontian Basin) modified after Gréselle et al. (2011), Mutterlose et al. (2020) and Kenjo et
1628 al. (2021); Angles section (Vocontian Basin) modified after Duchamp-Alphonse et al. (2007);
1629 Cehingin area (Subbetic Basin, SE Spain) modified after Aguado et al. (2000; 2018). The FO
1630 of *E. striatus* is situated in the *K. inostranzewi* StZ or *S. verrucosum* StZ according to the
1631 ammonite biostratigraphic interpretation of the Zalidou section (see 4.1. Ammonite
1632 stratigraphy).

1633
1634 Figure 10. Sedimentology, sequence stratigraphy and correlations (south-north transect) of
1635 Aït Hamouch, Zaouia Sidi Abderahmane and Zalidou sections from the southern part of the
1636 studied area. Caption on Fig. 11. Location on Fig. 1B.

1637

1638 Figure 11. Sedimentology, sequence stratigraphy and correlations (west-east transect) of
1639 Obbay, Igouzoulen and Ida w Iddar sections from the northern part of the studied area.
1640 Location on Fig. 1B.

1641

1642 Figure 12. Discontinuities and depositional sequences along a SSW-NNE transect including
1643 the Aït Hamouch, Zalidou and Ida w Iddar sections.

1644

1645 Figure 13. Correlations of the Essaouira-Agadir Basin (South Tethyan margin) with the
1646 south-east France Basin (North Tethyan margin). Lithological successions and carbon
1647 isotopic curves are simplified: Zalidou and Aït Hamouch sections after this work (Figs. 3 and
1648 4, respectively); Vergol-La charce composite section (Vocontian Basin) modified after
1649 Reboulet (1996), Gollain et al. (2019) and Kenjo et al. (2021), and completed for the lower
1650 Valanginian *p.p* by the isotopic data (dashed line) from the Angles section (Duchamp-
1651 Alphonse et al., 2007); Carajuan section (Provence Platform) modified after Bulot (1995),
1652 Reboulet (1996), Reboulet et al. (2003) and Gréselle and Pittet (2010). Note that the thickness
1653 scale of south-east France sections is 25% that of the Moroccan sections. For the Vocontian
1654 basinal section, the calcareous bundles are indicated and named according to the ammonite
1655 zonation; "Barrande" correspond to four organic-matter-rich layers (Reboulet et al., 2003); the
1656 shaded area is the interval of the Weissert Event from the onset of the carbon isotope
1657 excursion (CIE, indicated by a black arrow) until its climax (according to Erba et al., 2004).
1658 For the Carajuan section, F1 to F13 correspond to some sedimentary formations (see
1659 references above); the zonal scheme was updated according to the standard zonation

1660 (Reboulet et al., 2018). D1 to D8: Moroccan discontinuities after this work (Figs. 3–4); DCB:

1661 “Discontinuité au toit des Calcaires Blancs” after Bulot et al. (1995; 1997); SB D to SB H:

1662 discontinuities of Gréselle and Pittet (2010); DVM and DVS: “discontinuité du Valanginien

1663 moyen” and “discontinuité du Valanginien supérieur” of Autran (1993), respectively; DVT:

1664 “discontinuité du Valanginien terminal” of Bulot et al. (2010).
<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

Rif Alpine nappes (Paleozoic-Cenozoic)
Saharan basins (Cretaceous-Cenozoic)

Moroccan Meseta (Triassic-Cenozoic)
Atlantic basins (Permian-Cenozoic)

Central High Atlas (Triassic-Cretaceous)
Basement and Paleozoic basins

Holocene

Upper Cretaceous

Lower Cretaceous

Permian to Lower Jurassic

Cenozoic

«middle» Cretaceous

Middle-Upper Jurassic

Basement
<figure><img src="image_4.png" /></figure>

WEST

Formations

EAST
<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>
<figure><img src="image_7.png" /></figure>
<figure><img src="image_8.png" /><figcaption>Stages
Berriasian p.p.
lower Valanginian
upper Valanginian p.p.</figcaption></figure>

<table><caption>Ammonite zonation
Sample/bed
IGb-IGz

F. boissieri
14a
14b
14a

B. calisto
14a

"T" pertransiens ?
14a

"T" gratianopolitense ?
14a

Thurmanniceras sp. ind.
14a

N. premolicus
14a

N. premoicus/N. subtenus
14a

Neocomites sp. ind.
14a

K. paraplesium
14a

Karakaschiceras sp. ind.
14a

Sarasinella sp. ind.
14a

Kilianella ?
14a

K. roubaudiana
14a

O. guebhardi
14a

Olcostephanus sp. ind.
14a

V. ventratuberculatus
14a

V. dolioliformis
14a

Negreliceras sp. ind.
14a

H. silesiacum
14a

L. honnoratianum
14a

Fauriella sp. ind.
14a

D. Sedimentary discontinuities (D)
14a

D3

D4

D2

D1

D0

D-1

D-2

D-3

D-4

D-5

D-6

D-7

D-8

D-9

D-10

D-11

D-12

D-13

D-14

D-15

D-16

D-17

D-18

D-19

D-20

D-21

D-22

D-23

D-24

D-25

D-26

D-27

D-28

D-29

D-30

D-31

D-32

D-33

D-34

D-35

D-36

D-37

D-38

D-39

D-40

D-41

D-42

D-43

D-44

D-45

D-46

D-47

D-48

D-49

D-50

D-51

D-52

D-53

D-54

D-55

D-56

D-57

D-58

D-59

D-60

D-61

D-62

D-63

D-64

D-65

D-66

D-67

D-68

D-69

D-70

D-71

D-72

D-73

D-74

D-75

D-76

D-77

D-78

D-79

D-80

D-81

D-82

D-83

D-84

D-85

D-86

D-87

D-88

D-89

D-90

D-91

D-92

D-93

D-94

D-95

D-96

D-97

D-98

D-99

D-100

D-101

D-102

D-103

D-104

D-105

D-106

D-107

D-108

D-109

D-110

D-111

D-112

D-113

D-114

D-115

D-116

D-117

D-118

D-119

D-120

D-121

D-122

D-123

D-124

D-125

D-126

D-127

D-128

D-129

D-130

D-131

D-132

D-133

D-134

D-135

D-136

D-137

D-138

D-139

D-140

D-141

D-142

D-143

D-144

D-145

D-146

D-147

D-148

D-149

D-150

D-151

D-152

D-153

D-154

D-155

D-156

D-157

D-158

D-159

D-160

D-161

D-162

D-163

D-164

D-165

D-166

D-167

D-168

D-169

D-170

D-171

D-172

D-173

D-174

D-175

D-176

D-177

D-178

D-179

D-180

D-181

D-182

D-183

D-184

D-185

D-186

D-187

D-188

D-189

D-190

D-191

D-192

D-193

D-194

D-195

D-196

D-197

D-198

D-199

D-200

D-201

D-202

D-203

D-204

D-205

D-206

D-207

D-208

D-209

D-210

D-211

D-212

D-213

D-214

D-215

D-216

D-217

D-218

D-219

D-220

D-221

D-222

D-223

D-224

D-225

D-226

D-227

D-228

D-229

D-230

D-231

D-232

D-233

D-234

D-235

D-236

D-237

D-238

D-239

D-240

D-241

D-242

D-243

D-244

D-245

D-246

D-247

D-248

D-249

D-250

D-251

D-252

D-253

D-254

D-255

D-256

D-257

D-258

D-259

D-260

D-261

D-262

D-263

D-264

D-265

D-266

D-267

D-268

D-269

D-270

D-271

D-272

D-273

D-274

D-275

D-276

D-277

D-278

D-279

D-280

D-281

D-282

D-283

D-284

D-285

D-286

D-287

D-288

D-289

D-290

D-291

D-292

D-293

D-294

D-295

D-296

D-297

D-298

D-299

D-300

D-301

D-302

D-303

D-304

D-305

D-306

D-307

D-308

D-309

D-310

D-311

D-312

D-313

D-314

D-315

D-316

D-317

D-318

D-319

D-320

D-321

D-322

D-323

D-324

D-325

D-326

D-327

D-328

D-329

D-330

D-331

D-332

D-333

D-334

D-335

D-336

D-337

D-338

D-339

D-340

D-341

D-342

D-343

D-344

D-345

D-346

D-347

D-348

D-349

D-350

D-351

D-352

D-353

D-354

D-355

D-356

D-357

D-358

D-359

D-360

D-361

D-362

D-363

D-364

D-365

D-366

D-367

D-368

D-369

D-370

D-371

D-372

D-373

D-374

D-375

D-376

D-377

D-378

D-379

D-380

D-381

D-382

D-383

D-384

D-385

D-386

D-387

D-388

D-389

D-390

D-391

D-392

D-393

D-394

D-395

D-396

D-397

D-398

D-399

D-400

D-401

D-402

D-403

D-404

D-405

D-406

D-407

D-408

D-409

D-410

D-411

D-412

D-413

D-414

D-415

D-416

D-417

D-418

D-419

D-420

D-421

D-422

D-423

D-424

D-425

D-426

D-427

D-428

D-429

D-430

D-431

D-432

D-433

D-434

D-435

D-436

D-437

D-438

D-439

D-440

D-441

D-442

D-443

D-444

D-445

D-446

D-447

D-448

D-449

D-450

D-451

D-452

D-453

D-454

D-455

D-456

D-457

D-458

D-459

D-460

D-461

D-462

D-463

D-464

D-465

D-466

D-467

D-468

D-469

D-470

D-471

D-472

D-473

D-474

D-475

D-476

D-477

D-478

D-479

D-480

D-481

D-482

D-483

D-484

D-485

D-486

D-487

D-488

D-489

D-490

D-491

D-492

D-493

D-494

D-495

D-496

D-497

D-498

D-499

D-500

D-501

D-502

D-503

D-504

D-505

D-506

D-507

D-508

D-509

D-510

D-511

D-512

D-513

D-514

D-515

D-516

D-517

D-518

D-519

D-520

D-521

D-522

D-523

D-524

D-525

D-526

D-527

D-528

D-529

D-530

D-531

D-532

D-533

D-534

D-535

D-536

D-537

D-538

D-539

D-540

D-541

D-542

D-543

D-544

D-545

D-546

D-547

D-548

D-549

D-550

D-551

D-552

D-553

D-554

D-555

D-556

D-557

D-558

D-559

D-560

D-561

D-562

D-563

D-564

D-565

D-566

D-567

D-568

D-569

D-570

D-571

D-572

D-573

D-574

D-575

D-576

D-577

D-578

D-579

D-580

D-581

D-582

D-583

D-584

D-585

D-586

D-587

D-588

D-589

D-590

D-591

D-592

D-593

D-594

D-595

D-596

D-597

D-598

D-599

D-600

D-601

D-602

D-603

D-604

D-605

D-606

D-607

D-608

D-609

D-610

D-611

D-612

D-613

D-614

D-615

D-616

D-617

D-618

D-619

D-620

D-621

D-622

D-623

D-624

D-625

D-626

D-627

D-628

D-629

D-630

D-631

D-632

D-633

D-634

D-635

D-636

D-637

D-638

D-639

D-640

D-641

D-642

D-643

D-644

D-645

D-646

D-647

D-648

D-649

D-650

D-651

D-652

D-653

D-654

D-655

D-656

D-657

D-658

D-659

D-660

D-661

D-662

D-663

D-664

D-665

D-666

D-667

D-668

D-669

D-670

D-671

D-672

D-673

D-674

D-675

D-676

D-677

D-678

D-679

D-680

D-681

D-682

D-683

D-684

D-685

D-686

D-687

D-688

D-689

D-690

D-691

D-692

D-693

D-694

D-695

D-696

D-697

D-698

D-699

D-700

D-701

D-702

D-703

D-704

D-705

D-706

D-707

D-708

D-709

D-710

D-711

D-712

D-713

D-714

D-715

D-716

D-717

D-718

D-719

D-720

D-721

D-722

D-723

D-724

D-725

D-726

D-727

D-728

D-729

D-730

D-731

D-732

D-733

D-734

D-735

D-736

D-737

D-738

D-739

D-740

D-741

D-742

D-743

D-744

D-745

D-746

D-747

D-748

D-749

D-750

D-751

D-752

D-753

D-754

D-755

D-756

D-757

D-758

D-759

D-760

D-761

D-762

D-763

D-764

D-765

D-766

D-767

D-768

D-769

D-770

D-771

D-772

D-773

D-774

D-775

D-776

D-777

D-778

D-779

D-780

D-781

D-782

D-783

D-784

D-785

D-786

D-787

D-788

D-789

D-790

D-791

D-792

D-793

D-794

D-795

D-796

D-797

D-798

D-799

D-800

D-801

D-802

D-803

D-804

D-805

D-806

D-807

D-808

D-809

D-810

D-811

D-812

D-813

D-814

D-815

D-816

D-817

D-818

D-819

D-820

D-821

D-822

D-823

D-824

D-825

D-826

D-827

D-828

D-829

D-830

D-831

D-832

D-833

D-834

D-835

D-836

D-837

D-838

D-839

D-840

D-841

D-842

D-843

D-844

D-845

D-846

D-847

D-848

D-849

D-850

D-851

D-852

D-853

D-854

D-855

D-856

D-857

D-858

D-859

D-860

D-861

D-862

D-863

D-864

D-865

D-866

D-867

D-868

D-869

D-870

D-871

D-872

D-873

D-874

D-875

D-876

D-877

D-878

D-879

D-880

D-881

D-882

D-883

D-884

D-885

D-886

D-887

D-888

D-889

D-890

D-891

D-892

D-893

D-894

D-895

D-896

D-897

D-898

D-899

D-900

D-901

D-902

D-903

D-904

D-905

D-906

D-907

D-908

D-909

D-910

D-911

D-912

D-913

D-914

D-915

D-916

D-917

D-918

D-919

D-920

D-921

D-922

D-923

D-924

D-925

D-926

D-927

D-928

D-929

D-930

D-931

D-932

D-933

D-934

D-935

D-936

D-937

D-938

D-939

D-940

D-941

D-942

D-943

D-944

D-945

D-946

D-947

D-948

D-949

D-950

D-951

D-952

D-953

D-954

D-955

D-956

D-957

D-958

D-959

D-960

D-961

D-962

D-963

D-964

D-965

D-966

D-967

D-968

D-969

D-970

D-971

D-972

D-973

D-974

D-975

D-976

D-977

D-978

D-979

D-980

D-981

D-982

D-983

D-984

D-985

D-986

D-987

D-988

D-989

D-990

D-991

D-992

D-993

D-994

D-995

D-996

D-997

D-998

D-999

D-1000</caption><tr><td>Zones (standard zonation)</td><td>T. alpilensis p.p.</td></tr><tr><td>Subzones (* = local unit)</td><td>N. premo<sup>?</sup></td></tr></table>
<figure><img src="image_9.png" /></figure>

Sample/bed

Ammonite zonation
South-east France

Vergol-La Charge section, Vocontian Basin

<figure><img src="image_10.png" /></figure>

<figure><img src="image_11.png" /></figure>

Angles section, Vocontian Basin

<figure><img src="image_12.png" /></figure>

Essaouira-Agadir Basin (EAB), this study

<figure><img src="image_13.png" /></figure>

Cehegin area, Subbetic Basin

SE Spain

<figure><img src="image_14.png" /></figure>
S Aït Hamouch

13 km

23 km

N

HAUTERIVIAN p.p.

<figure><img src="image_15.png" /></figure>

upper VALANGINIAN

BERRIASIAN p.p.

<figure><img src="image_16.png" /></figure>

Ammonite zonation
(see section 4.1):

Zaouia Sidi Abderahmane

Be/Va/Ha: depositional sequence
D: Discontinuity

Zalidou

<figure><img src="image_17.png" /></figure>
<figure><img src="image_18.png" /></figure>

SSW

Aït Hamouch

Zalidou

Ida w Iddar

NNE
Essaouira-Agadir Basin (EAB) - Morocco

Alt Hamouch, simplified section

Zalidou, simplified section

South-east France Basin - Thickness x 1/4

Vergol-La Charce, simplified
section, Vocontian Basin

Carajuan simplified,
section,
Provence Platform

<figure><img src="image_19.png" /><figcaption>Stages
Ammonite zonation

nannofossil zonation

Ammonite age (Ma)</figcaption></figure>