Paleocene Larger Foraminifera from the Pyrenean Basin with a recalibration of the Paleocene Shallow Benthic Zones Special volume: Biochronology of the South Pyrenean Cenozoic, in memoriam

DOI: 10.1344/GeologicaActa2020.18.8  J. Serra-Kiel, V. Vicedo, J.I. Baceta, G. Bernaola, A. Robador, 2020 CC BY-SA J . S e r r a K i e l e t a l . G e o l o g i c a A c t a , 1 8 . 8 , 1 6 9 , I I I I ( 2 0 2 0 ) D O I : 1 0 . 1 3 4 4 / G e o l o g i c a A c t a y e a r 2 0 2 0 . 1 8 . 8 Paleocene LBF from the Pyrenean Basin

The study of Paleocene larger foraminifera from the Pyrenean basin received a major boost with the development of the International Geological Correlation Programme (IGCP) Project 286 "Early Paleogene Benthos". This project organized two workshops in the Pyrenean basin. The first was hold in Jaca (Spain), in October 1990. At this meeting, several papers concerning stratigraphy, biostratigraphy and sequential analysis of Paleocene outcrops in the Southern Pyrenees were presented by Robador (1991), Serra-Kiel et al. (1991), Robador et al. (1991a, b). The second workshop was organized in Aspet (France), September 1994, with contributions concerning the stratigraphy and biostratigraphy of Paleocene successions by Tambareau et al. (1994a, b, c).
The first zonation of larger foraminifera of the Paleocene series was developed by Hottinger (1960) based on alveolinids. This biozonation included the G. primaeva Zone for the lower Thanetian and the G. levis Zone for the upper Thanetian. Later, Schaub (1981) characterized the Assilina yvettae Zone for the late Thanetian based on nummulitids. As one of the main conclusions of the IGCP Project 286 "Early Paleogene Benthos", the first integrated biostratigraphic zonation for Paleogene platform series, the Paleogene Shallow Benthic Zones (SBZ), was published by Serra-Kiel et al. (1998).
These stratigraphic contributions were used by Baceta et al. (2004) to define the depositional sequences (DS) called Ma-Da, Da-1, Da-2, Se/Th-1 and Th-2, which encompass the entire Paleocene, and were later incorporated into various publications including a synthesis paper leading to the formal definition of the Global Stratotype Sections and Points for the bases of the Selandian and Thanetian stages .
The position of the Paleocene/Eocene boundary in shallow platform successions at the base of the Ilerdian stage has been of wide use in studies on larger foraminifera from the whole Tethyan domain over the last five decades. Several recent studies have demonstrated that the Carbon Isotopic Event (CIE) that globally marks the Paleocene-Eocene boundary accurately matches the base of the Ilerdian in the stratotype and parastratotype sections (Pujalte et al., , 2009aSchmitz and Pujalte, 2003)This points out that the Ilerdian is indeed an appropriate chronostratigraphic stage, at least at the scale of the Tethyan realm, useful to characterize the shallow platform successions deposited during the early Ypresian stage, as defined by the International Commission on Stratigraphy.
In this context, we present a new systematic study of Paleocene larger foraminifera with the description of two new species and a recalibration of the stratigraphic extent of several taxa. With this updated database, we propose a new recalibration of the SBZs from SBZ 1 to SBZ 4. In the Pyrenees, the Paleocene was a time of subdued tectonism, which developed under a semiarid to arid climate, globally rising sea levels and reduced siliciclastic supplies from the neighbouring emerged lands (Baceta, 1996;Baceta et al., 2004;Pujalte et al., 1993). The combined effect of these general conditions led to a transgression recorded across the whole Pyrenean embayment (Baceta, 1996;Baceta et al., 2004Baceta et al., , 2006aBaceta et al., , b, 2011Pujalte et al., 2000a, b;Robador, 2008). The general paleogeography during this time consisted of a large sub-tropical marine embayment opening to the paleo-Bay of Biscay and the North Atlantic, with a 1000-1500m deep central basin surrounded on its north, south and east sides by shallow marine areas, in turn, flanked by broad continental alluvial plains (Baceta, 1996; Fig. 1A, B). The shallow marine areas were largely characterized by the deposition of skeletal and non-skeletal carbonate sediments, forming platform systems that in most sectors reached 30 to 40km across dip and reached as much as 300-400m in composite thickness. These carbonate platforms originally covered a total area of at least 40,000km 2 .
The Paleocene platform successions from the Pyrenees consist mainly of shallow-water limestones deposited on beaches, tidal flats, lagoons, shoals and a variety of reef constructions, but also include minor proportions of siliciclastics and evaporites (Baceta et al., 2004. Pene-contemporaneous dolomitization likely produced by evaporative processes was particularly important during the Danian and middle Thanetian, and karstification took place during the Selandian, which largely represents a period of relative sea level lowstand , and during the Paleocene-Eocene boundary (Pujalte et al., , 2014. Basinwards, shallow carbonate platforms pass sharply, through narrow slopes, to hemipelagic deposits, in the form of rhythmic alternations of limestone, marlstone and marl, locally with intercalations of thin calcareous, siliciclastic and mixed turbidites. In slope and base of slope settings, the basinal hemipelagites also intercalate numerous shallow-derived carbonate breccias and bioclastic turbidites (Baceta, 1996). These resedimented deposits usually occur in the form of gully systems and apron-like accumulations (Baceta, 1996;Baceta et al., 2004;Pujalte et al., 1993;Robador, 2005). Landwards, the carbonate platform succession interfingers with alluvial-lacustrine coastal plain sediments. These non-marine deposits, extensively developed in the south-central Pyrenees, are classically known in the literature as the "Garumnian" facies, Tremp Formation, or Tremp Group (Cuevas, 1992;Eichenseer, 1988;López-Martínez and Peláez-Campomanes, 1999;Rosell et al., 2001;Schmitz and Pujalte, 2003).
The long-term transgressive trend of the Paleocene carbonate platforms was punctuated by third-order oscillations in relative sea level. The stratigraphic signature of these sea-level changes is a suite of regionally extensive Depositional Sequences (DS), which form the building blocks of the platform-to-basin Paleocene succession (Fig.  2). The five DS recognized have been coded according to their estimated chronostratigraphic range. Their features fit reasonably well with current models established for landattached carbonate platforms sensu Wright and Burchette (1996), although their character and stacking pattern vary significantly depending on the carbonate sediment types involved, the presence of siliciclastic sediments and the platform depositional profile (ramp or rimmed shelf) in each time slice (Baceta et al., 2004. In general, Paleocene DS consist mostly of transgressive and highstand system tracts and contain poorly developed lowstand system tracts. Their boundaries correspond to discontinuity surfaces with numerous features of subaerial exposure, clear evidence of drops in sea level. The most prominent and longest lasting of these lowstands took place during the Danian-Selandian boundary and caused the complete exposure of the Danian platform succession and the formation of a complex paleokarst system for a period of about 2.5m.y. . The establishment and platform-to-basin correlation of the Paleocene DS solved many of the incongruences and misinterpretations in the numerous formal and informal lithostratigraphic units established within the Pyrenean Paleocene stratigraphic record (Garrido-Megías and Rios, 1972).
representative inner platform-to-coastal plain settings (Tremp, Campo), the platform margin (Lizarraga pass) and base of slope (Aixola-Ermua, Monte Urko), all correlated with the reference basinal section of Zumaia. This chronostratigraphic framework incorporates the recently adopted formal position of the Danian-Selandian, Selandian-Thanetian and Paleocene-Eocene boundaries .

Description of the stratigraphic sections
For this work, we have selected a series of stratigraphic sections that contain larger foraminifera ranging from transitional continental-marine realms, to inner platform, middle platform, the platform margin, the base of slope and hemipelagic environments. For the correlation among the different taxa of biostratigraphic use, special attention has been paid to stratigraphic sections with intercalations of deposits with calcareous plankton of biostratigraphic significance and to sections of platform slope and hemipelagic environments with calciturbidites that contain larger foraminifera that can be considered penecontemporaneous to planktonic foraminifera and calcareous nannoplankton.
The profiles selected run east-northwest across the Paleocene basin axis (Fig. 1C) and permit precise correlation of the larger foraminiferal zones (SBZ) with those of the calcareous nannoplankton (NP, CNP) and planktonic foraminifera (P).
The description of the studied sections presented below takes as reference the Paleocene stratigraphic units defined in Figure 2. In all stratigraphic sections, the lithology is represented according to the legend set out in Figure 3.

Serraduy section
Serraduy section (Fig. 4) was measured on the west and east banks of the Isabena River and adjacent hillslopes, all located some 500-800m to the north of the village of Serraduy.
The base of the section is marine sandy limestone of the Arén Formation (Fm.) (Mey et al., 1968), Maastrichtian in age. The non-marine deposits encompassing the first interval described (Ma-Da to IL-1 depositional sequences) were referred as Garumnian facies by Leymerie (1868). Later Garrido-Megías and Ríos (1972) detailed the stratigraphy of this part of the section separating the continental deposits (their Laspún Fm.) from the marine Da-2 DS. It is represented by lacustrine limestone capped by two well-developed pedogenetic horizons corresponding to the Colmenar-Tremp horizon (Eichenseer, 1988).
Se/Th-1 DS. The basal limit of this sequence is the top of the pedogenetic horizon of the previous DS. This unit is made up of continental red and variegated clays and includes a marine intercalation in its upper part. This level is composed of a conglomeratic layer sandwiched between two shallow marine limestone beds with foraminifera. The uppermost part of the unit is again composed of red clays with nodular calcareous concretions. The occurrence of I. sinjarica, G. primaeva, K. aquitanica and C. carniolica in this stratigraphic interval characterizes SBZ 3.
Th-2 DS. This depositional sequence starts with a 1m-thick sandy conglomeratic bed, followed by 10m of sandy limestone with abundant marine fossils, including oysters, corals and abundant larger foraminifera, followed by sandstone. The upper part of this DS consists of greenish-red bioturbated continental clays. The occurrence of D. garumnensis and G. levis in this DS is characteristic of SBZ 4.
The lower undifferentiated red clay unit (DS Ma-Da and Da-1) and the depositional sequences Da-2, Se/Th-1 and Th-2 have been referred to as the Laspún Fm. by Garrido-Megías and Ríos (1972).

IL-1 DS. The bottom of this unit is formed by an
incised channel with a conglomeratic infill overlain by a 6m-thick layer of calcareous sandstone and red clays. The remaining of the sequence is composed of two limestone intervals separated by a unit built up of unconsolidated rock, generally covered, consisting of marlstone and calcareous sandstone with plant remains, which indicate regressive conditions. The first of these two calcareous beds is a bioclastic, shallow marine limestone with very abundant Alveolina, that has been interpreted as as a giant sandwave. The occurrence in this DS of A. vredenburgi vredenburgi and A. globula indicates SBZ 5 in the lower part of IL-1, whereas in its upper part A. vredenburgi tumida and A. ellipsoidalis are indicative of SBZ 6. These deposits are included in the Serraduy Fm. (Cuevas-Gozalo et al., 1985).

Campo section
Campo section (Fig. 5) is located in the Ésera river gorge, south of the town of Campo. The section begins at km 4 along the N-260 road, following the path of the ancient, abandoned road, and crossing the Ésera Bridge towards the town of Ainsa.
UTM coordinates (ETRS89, H31) are X: 285.738, Y: 4.696.911 (bottom) and X: 285.660, Y: 4.696.180 (top). This section exposes a relatively thick succession of Paleocene to lower Ilerdian platform carbonates, arranged in up to six depositional sequences (Fig. 5). The underlying Maastrichtian deposits are sandy limestones pertaining to the Arén Fm. The depositional sequences Ma-Da, Da-1 and Da-2 belong to the Laspún Fm. (Garrido-Megías and Ríos, 1972), whereas Se/Th-1 and Th-2 deposits build up the Navarri Fm. (Garrido-Megías and Ríos, 1972). The continental deposits from the top of the Arén Fm. to the base of the Se/Th-1 sequence were characterized as Garumnian facies by Leymerie (1868). Ma-Da DS. This is a heterolithic unit composed of sandstones and marls in its lower part, a sandstone unit with rudist debris in the middle part, and an upper part build up of dolomicrite and red clays.
Da-1 DS. It is made up of secondary dolomites with calcareous algae and microfossil ghosts.
Da-2 DS. It is formed by white dolomicrites in its lower part, capped by some beds of oolitic limestones of lacustrine facies. The upper part begins with a collapse breccia composed of honeycomb-like dolomite followed by red and variegated clays and lacustrine limestone. Its upper limit is marked by a widespread paleosol catena, called the Colmenar-Tremp Horizon (Eichenseer, 1988). Se/Th-1 DS. The basal levels are composed of red-grey claystones and dolomites. The main body of this unit is composed of bioclastic, very fossiliferous limestones, deposited in lagoon/inner shelf environments. The regressive upper part of the section includes dolomites accumulated in supratidal marsh environments including an intercalation of continental clays with vertebrate remains (Tambareau et al., 1992a). The larger foraminifera G. primaeva, V. anatolica, C. rajkae, C. carniolica, K. aquitanica, D. praegarumnensis, M. yvettae, M. primitivus and C. ovoidea characterize SBZ 3.
Th-2 Ds. This is a transgressive unit composed mainly of very fossiliferous bioclastic limestones. Its central part has been interpreted as the deepest facies association of the entire Paleocene interval, and is represented by marls and marly limestones with autochthonous assemblages of calcareous nannofossils (Orue-Etxebarria et al. 2001). The middle and upper parts of this sequence is characterized by sandy, bioclastic and cross-bedded bioclastic limestones. In the uppermost part of the sequence, there are reefal boundstones. The top of this DS is a 5m-thick layer of mudstones with exhibits pedogenetic alteration and abundant Microcodium, indicating subaerial exposition. The presence in this unit of G. levis, D. garumnensis, A. yvettae and A. azilensis characterizes SBZ 4. The calcareous nannofossil assemblages recorded in the nine Paleocene LBF from the Pyrenean Basin 10 samples collected in the upper part of Th-2 are indicative of Zone NP9 of Martini (1971) or Zone CNP11 of Agnini et al. (2014).

IL-1 DS.
Thi unit begins with continental clays and sandstones, where the geochemical signal of the CIE of the Paleocene-Eocene thermal maximum has been located (Pujalte et al., 2009b;Schmitz and Pujalte, 2003). The upper part of the unit is made up of bioclastic limestone with Alveolina including A.v. vredenburgi, which characterizes SBZ 5.

Tena section
Tena section (Fig. 6)  The rocks underlying the Paleocene succession belong to the Marboré Fm. (Souquet, 1967) ands are mostly composed of sandstone and marlstone. Both Da-1 and Da-2 depositional sequences are referred to in the literature as the Salarons Fm. (Van de Velde, 1967). The depositional sequences Se/Th-1, Th-2 and IL-1 belong to the Gallinera Fm. (Van de Velde, 1967).

Da-1 DS.
This unit is composed of dolomites and shallow marine limestones capped with intraformational breccia at top. The occurrence of B. hanseni at top is characteristic of SBZ 1.

Da-2 DS.
This unit is characterized by shallow marine limestone with algal laminations, dolomites and shallow marine limestones at the top. Unfortunately, the absence of the larger foraminifera does not alow for a determination of the biostratigraphic range of this DS.
Se/Th-1 DS. The basal levels of this depositional sequence are characterized by sandstone and shallow sandy limestone, followed by algal boundstones and topped by shallow marine limestones. The occurrence of G. primaeva, V. anatolica, F. alavensis, C. carniolica, "O". heberti and D. seunesi characterizes SBZ 3.
Th-2 S. This unit is composed of very fossiliferous shallow marine sandy limestones. The occurrence of G. levis, A. yvettae and A. azilensis characterizes SBZ 4.

IL-1 DS.
The bottom of this unit is represented by bioclastic sandy silt with abundant nummulitids followed by bioclastic limestone rich in alveolinids. The occurrence N. aff. minervensis and A.v. vredenburgi characterizes SBZ 5.

Garralda section
Garralda section (Fig. 7) was measured along a path that leaves the village of Garralda towards the north. It begins at the base of an abandoned limestone quarry and continues northward after a small water reservoir.

Da-2 DS.
This unit is represented at its lowest part by a 1.5m-thick breccia composed of clasts made of limestone and marly clay chips. Above, the succession is composed of a 40m-thick, monotonous succession up of coarsening upwards bioclastic limestones with calcareous algae (rhodophyte) bioclasts. The occurrence in this unit of M. globularis, O. moorkensii and E. dienii is characteristic of SBZ 2.
Se/Th-1 DS. This unit is composed in its lower part by sandy, fine grained limestones, which overlies Da-2 deposits with a sharp, erosive contact. The upper half of the sequence is made of bioclastic limestones, where V. anatolica, K. aquitanica and M. yvettae where found and indicate SBZ 3.
Th-2 DS. This unit is composed in its basal levels by sandy limestones which abruptly overlie the bioclastic limestones of the previous sequence followed by bioclastic limestones with calcareous algae and corals.
IL-1 DS. This DS is made of alternating marls and marly limestones with abundant planktonic foraminifera. Due to their incompetent nature, their outcrops are very scarce, with its lower boundary being usually covered.

Urrobi section
Urrobi section (Fig. 8) was measured in year 1994 on the left bank of the Urrobi river south of the village of Nagore; however, it is no longer accessible as the area has been flooded by the Itoiz reservoir.

IL-1 DS.
The bottom of this sequence is formed by bioclastic sandy silt with abundant nummulitids where the geochemical signal of the CIE is located according to Pujalte et al. (2003). These rocks are followed by a bioclastic limestone rich in nummulitids, with N. aff. minervensis indicating SBZ 5.

Andia section
Andia section (Fig. 9) was logged on the edge of the plateau located approximately 1.5km to the east of the Lizarraga mountain pass. It is provided here as subsidiary section of the Lizarraga section, described below. This Paleocene LBF from the Pyrenean Basin 14 section is relevant in the Western Pyrenees as it is the only including Selandian deposits in shallow water facies, most of them relatively rich in larger foraminifera.

Se/Th-1 DS
This sequence lies unconformably on upper Danian "Lizarraga reef complex" and is overlain by unnamed Ilerdian deposits. The succession is made up of marlstones and marly limestones interbedded with several m-thick intervals of bioclastic limestones and very locally coralgal boundstones (Baceta et al., 2005). The stratigraphic interval logged is laterally equivalent to the informal unit known as Usabide reef complex (Baceta et al., 2005). The bioclastic limestones comprise a varied association of foraminifera indicative of the SBZ 3 biozone, namely, G. primaeva, V. anatolica, C. rajkae, M. primitivus, "O". heberti and D. seunesi. According to G. Bernaola in Baceta et al. (2005), the logged section encompasses the NP5, NP6, NP7 and NP8 calcareous nannofossil zones of Martini (1971). The revision of these data allowed us to recognize in the same interval the CNP7, CNP8, CNP9 and CNP10 calcareous nannofossil zones of Agnini et al. (2014).

Lizarraga section
Lizarraga section (Fig. 10) is located along the NA-120 road from Etxarri-Aranatz to Estella/Lizarra across Lizarraga mountain pass, on the northern edge of the Urbasa-Andia synclinorium.
The section consists of an up to 360m-thick Paleocene to Early Eocene platform margin succession including different intervals with calcareous nannofossils allowing for an accurate age determination. The Paleocene overlies conformably the Maastrichtian deposits (Puerto de Olazagutia Fm., Amiot, 1982). The Da-2 DS is informally known as the Lizarraga reef complex, while the Se-Th-1 DS is laterally equivalent to the so-called Legumbe reef complex and DS Th-2 to the so-called "Assilina beds". (Baceta et al., 2005).
Th-2 DS. This is a comparatively thin unit, mostly composed of marlstone and marly limestones of open platform deposits with abundant planktonic fossils, laterally-equivalent to the upper Thanetian "Assilina beds" (Baceta et al., 2005). Calcareous nannofossils are of late Thanetian age, specifically belonging to Zones NP9 or CNP11 (Baceta et al., 2005).
IL-1 DS. This unit is composed of marly limestone, marls and limestone. The NP10 or CNE2 (Eocene) age of this unit was established by Baceta et al. (2005).

Urbasa Pass section
Urbasa Pas section (Fig. 11) is located on the northern flank of the Urbasa-Andia synclinorium, along the NA-718 road from the Urbasa (Olazagutia) road pass to the Bidoiza campsite. It represents an up to 300m-thick Paleocene to lower Eocene succession belonging to marine platform facies lacking Selandian deposits.
The Paleocene rocks lie on erosional contact over the Maastrichtian Puerto de Olazagutia Fm. (Amiot, 1982). The Ma-Da DS has been informally called the "Solenomeris limestone", while the Th-2 was called the "Assilina beds" by Baceta et al. (2005). The same authors called the deposits of IL-1 DS the "Nummulites-Alveolina limestone".

Da-1 DS.
This unit is composed of stratified to massive bioclastic limestone and reefal boundstones culminating with cross-bedded deposits. Most of these facies are affected by intense but patchy secondary dolomitization. This stratigraphic interval was informally defined as the Santa Marina reef complex by Baceta et al. (2005). The lesser-dolomitized beds contain M. globularis and O. moorkensii indicating SBZ 2 (lower part).
Se/Th-1 DS. The unit begins with a marlstonedominated interval that vertically evolves into bioclastic and massive red algae-coral boundstones overlain by bioclastic limestones, eventually with cross bedding and sandy intercalations. These beds are laterally equivalent to the Legumbe reef complex (Baceta et al., 2005). The DS contains a rich association of larger foraminifera, including G. primaeva, M. juliettae, M. primitivus, "O." heberti, R. soldadensis and D. seunesi, which belong to SBZ 3.

Th-2 DS.
It is composed of marlstone and thin beds of bioclastic limestones. These contain numerous A. azilensis indicating SBZ 4.

Leortza section
Leortza section (Fig. 12) is located along the A3114 road, in the river gorge located between the localities of Leortza/Elortza and Cicujano/Zekuiano, on the northern flank of the Maestu diapir. It encompasses a complete succession of shallow marine Maastrichtian to lowermost Eocene carbonates and siliciclastic rocks. However, the present study focuses on the upper Paleocene interval (Se/ Th-1 and lower part of the Th-2 sequences). The stratigraphic interval represented by DS Se/Th-1 was informally called the "Legumbe reef complex", while the deposits of Th-2 DS were called the "Assilina beds" (Baceta et al., 2005).
Paleocene LBF from the Pyrenean Basin 17 Se/Th-1 DS. This unit lies unconformably on dolomitized and karstified Danian deposits of the San Justi Fm. (Mangin, 1960) and begins with a thin and discontinuous bed of Qz-rich microconglomerates and sandy limestones. The bulk of the sequence consists of bioclastic limestones comprising a prominent interval, rich in red algae, bryozoans and corals, while stratified marlstones and dolomites occur atop. The presence of the larger foraminifera V. anatolica, C. rajkae, F. alavensis, M. yvettae, M. juliettae, "O." heberti and D. seunesi among others indicates SBZ 3 for this stratigraphic interval. Additionally, it includes the type-locality beds of Fallotella alavensis.
Th-2 DS. This unit consists of bioclastic sandy silts with intercalations of bioclastic limestones rich in A. azilensis indicating SBZ 4.

Korres section
The section (Fig. 13) is located in some cliff outcrops 300m west of the town of Korres, close to the A-3138 road to Durruma Kampezu. The section comprises a complete succession of upper Paleocene to lower Eocene deposits (Th-2 and Il-1).
The studied units overly a lower-middle Thanetian succession equivalent to the Se/TH-1 sequence at Leortza. The interval corresponding to the DS IL-1 was informally called the Ilerdian Alveolina limestone (Baceta, 1996).
Th-2 DS. The lower part of this unit is formed by sandy limestones with cross stratification, grey silt and sandy marlstone that vertically evolve into bioclastic limestones. This stratigraphic interval has been informally named the "Assilina "O." Paleocene LBF from the Pyrenean Basin 19 beds" (Baceta et al., 2005). The top is a prominent paleokarst surface that defines the Paleocene-Eocene boundary (Baceta, 1996). The presence in this stratigraphic interval of G. levis, H. lukasi, D. garumnensis and A. yvettae indicates the SBZ 4. The sample K 2 located in this DS is the type-locality of the new species: A. korresensis and V. bacetai.
IL-1 DS. It consists of a basal 6-7m-thick interval of unfossiliferous marlstone and sandy limestone with cross stratification overlain by bioclastic limestones including A. aramea aramea and A. v. vredenburgi which indicates SBZ 5.

Aixola-Ermua section
Aixola-Er mua section (Fig. 14) is a composite section from two laterally-equivalent outcrops (Aixola-Egoarbitza and Er mua) located respectively on the souther n and nor ther n f lanks of the Egoarbitza syncline (SE tip of the Biscay sinclinorium). Both are accessible from the town of Er mua, along the local GI-121 road to the Aixola dam and reservoir.
The Aixola-Egoarbitza section is located just north of the dam, with UTM coordinates (  The underlying Maastrichtian deposits are marlstones with turbidite intercalations of the Urko Fm. (Mathey, 1982). In both outcrops, the Paleocene succession is a complex series of base-of-slope and basinal deposits, approaching 122m in composite thickness, arranged in five DS. The deposits of the Da-1 and Da-2 DS belong to the Aitzgorri Fm. (Bernaola et al., 2009), while those of the Se/Th-1 and Th-2 DS belong to the Itzurun Fm. (Baceta et al., 2005).

Ma-Da DS.
This unit is only well-exposed in some accessory outcrops to the east of the main Aixola outcrop, where it comprises 14m of the upper Maastrichtian deposits, the K/Pg boundary layer and 6m of hemipelagic limestone with thin calcareous turbidites of earliest Danian age.
Da-1, Da-2, Se/Th-1 and Th-2 DS. All these units are bounded by discontinuity surfaces and internally consist of calcareous breccias deposits overlain by hemipelagic limestones and marlstones with interbedded platform and slope-derived calciturbidites and/or siliciclastic turbidites. Calcareous nannofossil data from this study, allow the identification of the Selandian-Thanetian boundary in an interval a few meters above the NP5-NP6 zone boundary. This interval also records the first occurrence of "O." heberti (SBZ 3). The calcareous nannofossil assemblages studied here from the Da-2 and Se/Th-1 DS correspond to NP4, NP5, NP6, NP7 and NP8 of Martini (1971) and CNP6, CNP7, CNP8, CNP9 and CNP10 zones of Agnini et al. (2014) (Figure 14).
The upper part of the section (Th-2 DS and IL-1 DS) was previously studied by Monechi in Orue-Etxebarria et al. (1996), who attributed them to the calcareous nannoplancton Zones NP9 and NP10 respectively, which correspond to CNP11 and CNE1 of Agnini et al. (2014). The zonation of this section based on planktonic foraminifera was established by X. Orue-Etxebarria in Pujalte et al. (1993).

IL-1 DS.
The base of this sequence is an erosional discontinuity marking an abrupt change to clay-rich facies with turbidites of mixed composition containing larger foraminifera indicative of SBZ 5, such as N. cf. gamardensis. The geochemical signal of the CIE marking the Paleocene-Eocene boundary is located in the base of this DS according to Pujalte et al. (2009a, b).

Urko section
Urko section (Fig. 15) is located on the northern flank of the Biscay sinclinorium, on the eastern hillside of Urko peak, some 3km north of the towns of Eibar and Ermua (Gipuzkoa province). The section is accessible along a path from the Ixua road pass, onthe GI-3950 road.
Overlying the Monte Urko Fm. composed of typically reddish-purple hemipelagic rocks and above the K/Pg boundary layer, there are grey-pinkish limestones and marlstones with numerous intercalations of platformderived calciturbidites belonging to the Danian stage (Baceta, 1996). This Danian succession is equivalent to the Aitzgorri limestone Fm. exposed in the type locality of Zumaia (Bernaola et al., 2009), and as there it can be subdivided into three intervals corresponding respectively to the Ma-Da, Da-1 and Da-2 DS. Their boundaries are conformity surfaces without recognizable stratigraphic hiatus.
The absence of larger foraminifera in most platformderived turbidites of the Ma-Da DS and the lower part of the Da-1 DS prevent a precise characterization of the SBZ1-SBZ2 boundary. SBZ 2 is indicated by the larger foraminifera K. decastroi, E. dienii, O. moorkensii and P. eos from the middle part of the Da-1 to the Da-2 DS.
Calcareous nannofossils of the 29 samples collected in the Danian of Urko section allowed the identification of four calcareous nannofossil zones defined by Martini (1971) for the Danian and the seven zones defined by Agnini et al. (2014) for the same interval (Fig. 5). Following the amendments introduced by Perch-Nielsen (1981,1985), we have used the first occurrences of Cruciplacolithus primus large and Cruciplacolithus edwarsii to define the base of zones NP2 and NP3. Ellipsolithus macellus, whose first occurrence marks the base of NP4, is very scarce and it has a discontinuous distribution in the upper part of the section.    Description. Test porcelaneous with ovoid morphology and miliolid growth. Dimorphism marked. The megalospheric forms show an elliptical outline in longitudinal section and subcircular outline in perpendicular section. The major diamenter for three whorls is 0.8mm and 1.25mm for four whorls. The proloculus is spherical, 140-170µm in diameter, with a flexostyle followed by chambers in quinqueloculine arrangement, becoming bilocular in later stages of growth. The trematophore is supported by thin pillars (Fig. 16B-16D). The undulate basal layer does not exceed half of the chamber height ( Fig. 16B-16D). The microspheric generation has a thick basal layer and a subcircular outline in axial section (Fig. 16).
Distribution. This species has been identified in Se/ Th-1 DS of the following sections: Serraduy section ( Biozone. Drobne (1974) identified this species in rocks from Slovenia considered as belonging to the interval from G. primaeva Zone to A. ellipsoidalis Zone. According to Serra-Kiel et al. (1998), its biostratigraphic range extends from SBZ 3 to SBZ 6. In this work I. sinjarica is associated to assemblages belonging to the SBZ 3. Description. Test porcelaneous with lenticular, flat morphology. The proloculus has a diameter of 70µm followed by 8-9 planispiral chambers (Fig. 16F, H). The single aperture, located at the bottom of the apertural face, shows a peristome (Fig. 16E, H). Later stage of growth composed of chambers arranged in an uncoiled-uniserial pattern with cribrate apertures. Microspheric forms not found.

Genus Kayseriella sirel
Distribution. This species is present in Da-1 DS of the Urko section ( Fig. 15), , in the Da-2 DS of the Lizarraga section ( Fig. 10), and in the Urbasa Pass section (Fig. 11), with the species assemblage indicated in the aforementioned figures.
Biozone. Sirel (1998) found this species in Danian rocks from Turkey. Later, Ogorelec et al. (2001) found it in the Danian and Selandian from Slovenia. According to the data presented herein this species can be considered as a marker of the SBZ 2. Description. The test is porcelaneous with ovoid morphology and miliolid growth. The dimorphism is strong. The megalospheric generation begins with a flexostylic proloculus, of around 150µm in diameter, followed by chambers in triloculine arrangement (Fig. 16K). The basal layer forms longitudinal ridges, occasionally reaching the chamber roof ( Fig Biozone. Drobne (1974) identified this species in Thanetian rocks (G. primaeva Zone) from Slovenia. As pointed out by Serra-Kiel et al. (1998) its biostratigraphic range is SBZ 3. This species can be considered as a marker for SBZ 3.  (Robador, 2005, Annex, p. 22-23).

Genus Pseudolacazina caus
Description. Porcelaneous test with spherical morphology and miliolid growth. The dimorphism is marked. Megalospheric forms have an outline elliptical in longitudinal section and subcircular in perpendicular section (Fig. 16Q). The proloculus is spherical with a diameter of 140µm followed by chambers in biloculine arrangement. The basal layer forms numerous longitudinal partitions subdividing chambers into chamberlets ( Fig. 16M, N, Q). Microspheric forms not found. Biozone. Drobne (1974) found this species in the G. primaeva Zone and in the A. ellipsoidalis Zone in rocks from Slovenia. Drobne in Serra-Kiel et al. (1998) extended the biostratigraphic range from SBZ 4 to SBZ 6. In the material studied P. donatae is associated with species typical of the SBZ 3. Consequently, we extend its biostratigraphic range from SBZ 3 to SBZ 6. Description. The test is porcelaneous with elongate, cilindrical to high conical morphology in the adult forms. The wall is thick and contains agglutinated grains on the surface. The embryonic and nepionic stages have not been adequately observed. The ephebic stage is composed of chambers in uniserial arrangement, showing a maximum length of 2.25mm and a diameter of 0.65mm for 8 uniserial chambers (Fig. 17A). The sutures are slightly depressed. The aperture is single, with a star-shaped outline ( Distribution. This species has been identified in Da-2 DS in the Lizarraga section ( Fig. 10) and in Urbasa Pass section ( Fig. 11) with the species assemblage indicated in the aforementioned figures.

Haymanella elongata sirel, 2009
Description. The test is porcelaneous with elongate morphology and thick wall. The embryonic apparatus has Paleocene LBF from the Pyrenean Basin 27 not been adequately observed. The nepionic stage of growth consists of chambers planispirally arranged (Fig. 17S). The ephebic stage shows uniserial chamber arrangement, with a maximum longitudinal section of 1.6mm and a diameter of 0.35mm with 8 uniserial chambers (Fig. 17O). The single, star-shaped aperture is located in interiomarginal position in the nepionic stage ( Fig. 17R) and in terminal position in the ephebic stage (Fig. 17P, Q) Distribution. This species appears in Da-2 DS of the Lizarraga section (Fig. 10) and the Urbasa Pass section ( Fig. 11) with the species assemblage indicated in the aforementioned figures.
Biozone. sirel (2009) found H. elongata in Danian and Selandian from Turkey. In the material studied, this species can be considered as a marker for the SBZ 2.
Praerhapydionininae indet. Remarks. The wall texture and the uniserial ephebic chamber arrangement suggest that this species belongs to the subfamily Praerhapydionininae; however, the biserial nepionic chamber arrangement is different from the planispiral coiling of the other genera ascribed to this subfamily. The Cretaceous genus Pseudorhapydionina de castro, 1971 with nepionic biserial arrangement, has cribrate aperture and a well-developed exoskeleton. The lack of sufficient material leads to leave these specimens undetermined.
Distribution. This species is present in the depositional sequences Da-2 DS from Urbasa Pass section (Fig. 11), Se/Th-1 DS from Andia section ( Fig. 9) and in Lizarraga section ( Fig. 10) with the species assemblage indicated in the aforementioned figures.
Biozone. This species was found associated to assemblages of larger foraminifera that belong to the SBZ 2-SBZ 3 (Fig. 9). Material. Samples K 1 and K 2 from Korres section (Fig. 13).
Description. The test is porcelaneous with lenticular morphology and planispiral involute growth. The maximum equatorial diameter observed is about 1.65mm and the wall is 0.8mm-thick. The endoskeleton consists only of a thin basal layer. The exoskeleton is composed of short beams ( Fig. 16R-S). The aperture is located at the base of the septum.

Remarks.
The embryonic architecture of this species could not be observed in the material studied due to the lack of a centred section.
Distribution. This species has been identified in the Th-2 DS from the Korres section ( Fig. 13) with the species assemblage indicated in the aforementioned figures.

Glomalveolina levis
Description. The test is porcelaneous with ovoidfusiform morphology. The megalospheric form shows an embryonic stage composed of a proloculus with a diameter of about 85µm followed by a flexostyle, the nepionic stage of 2-3 streptospiral whorls and a diameter of about 150µm (Fig. 18I). The possible microspheric forms (Fig. 18K) differ from the megalospheric form in possessing a tighter and smaller nepionic stage. In both generations, the ephebic stage consists of 7-8 whorls with planispiral chamber arrangement. The chamber lumen of the ephebic stage is subdivided into chamberlets by septula. Septula alternate in position in successive chambers. The elongation index is 1.3-1.7.
Distribution. This species is identified in Th-2 DS in the Serraduy section (Fig. 4), Campo section (Fig. 5), Tena section and in Korres section ( Fig. 13) with the species assemblage indicated in the aforementioned figures.
Biozone. According to Hottinger (1960) and Serra-Kiel et al. (1998)  Diagnosis. Porcelaneous test, axially elongated morphology with rounded poles. Multiple apertures. Microspheric forms not found. Megalospheric form with a nepionic stage that consists of a proloculus of circular outline in axial section and a diameter of 140-190µm followed by a flexostyle. Nepionic stage composed of 2 tight whorls, ephebic stage formed by 5 whorls. Maximum axial and equatorial diameters observed of 1.3-1.6mm and 0.5-07mm respectively, with an elongation index of 2.0-2.1. Chamberlets in the nepionic stage showing a subrectangular outline in axial section becoming oval to subrectangular in ephebic whorls. Endoskeleton consisting of a thin basal layer and septula subdividing chambers into chamberlets. Septula alternating position in successive chambers.
Remarks. This species is the oldest representative of the genus Alveolina in the Paleocene from the Pyrenean basin. It differs from A. vredenburgi davies and pinfold, 1937 (=ex A. cucumiformis) in the smaller size of the test and in the thickness of the basal layer.
Distribution. This species is present in Th-2 DS in the Korres section ( Fig. 13) with the species assemblage indicated in the aforementioned figure.

Class GLOBOTHALAMEA
Description. The specimens show a finely agglutinated test of small size. The embryo consists of an ovoidal proloculus with a maximum diameter of around 135-120µm and minimum of around 80-110µm. The neanic stage is composed of biserial chambers followed by the ephebic stage characterized by chambers arranged uniserially.
Distribution. This species has been identified in the DS Da-2 of the Urbasa Pass section (Fig. 11) and in samples from the lower part of the sections of Abaurrea and Foz de Biniés (see Robador, 2005). It is associated with species without biostratigraphical interest such as Lenticulina sp. and Robulus sp.
Biozone. Ogorelec et al. (2001) consider that this species belongs to the SBZ 2. This zonal assignment is in accordance with the data obtained in the Urbasa Pass section (Fig. 11). Its occurrence in the lower levels of the sections of Abaurrea and Foz de Biniés studied by Robador (2005) indicates that this species could also be present in SBZ 1. Material. Samples L 8 and L 9 from Lizarraga section (Fig. 10); samples Urb 2, Urb 4, Urb 6, Urb 7, Urb 13, Urb 25, Urb 27 and Urb 28 from Urbasa Pass section (Fig. 11); sample Le 2 from Leortza section (Fig. 12) and samples Aix 5 and Er 5 from Aixola-Ermua section (Fig. 14).

Superfamily Coscinophragmatoidea
Description. The wall is composed of two layers, the external layer consists of coarsely agglutinated particles, mainly of quartz, calcareous cement, and a thin inner layer formed of micrite, which is poorly preserved in the material studied. The morphology is irregular, showing protuberances on the external surface. Chambers are also irregular in shape. Paleocene LBF from the Pyrenean Basin 32 to "seagrasses" and substrates from reef environments developed in the inner shelf. It has no biostratigraphic significance.
Description. The shell is agglutinated, flattenedirregular in shape, with branches. The ephebic stage shows chambers in uniserial distribution. The wall is composed of three layers: the outer part consisting of a homogeneous calcareous layer, the inner layer composed of large quartz grains and the median layer is pierced by canaliculi perpendicular to the surface of the test. The apertures are cribrate.
Distribution and age. The morphology of this species suggests that it lived attached to the substrate, probably on the "seagrass" and on otherv substrates of reef environments of the inner shelf. It has no biostratigraphic significance.  (Robador, 2005, Annex, pp. 78-79).

Superfamily: Lituoloidea
Description. The test is coarsely agglutinated with a thick wall. The nepionic stage consists of a proloculus followed by planispirally arranged chambers. The ephebic stage, consisting of uniserially arranged chambers, is not present in the single specimens found.

Remarks. The specific determination of this taxon
has been left open since the ephebic stage could not be observed.
Distribution. In the material studied K. cf. paleocenica is associated with M. minutus and T. madrugaensis.
Biozone. According to Sirel (1998) this species occurs in the Danian from Turkey. These data and the results presented here indicate that its biostratigraphic range is within SBZ 3.  fig. 1-2 Material. Samples Urb 2 and Urb 3 from Urbasa Pass section (Fig. 11) and sample Le 2 from Leortza section (Fig. 12).
Description. The test is flattened with irregular morphology. Wall thick and formed of coarse agglutinated particles. Each chamber overlaps the previous, forming a relief on the surface of the test. The apertures are located in the base of the septum and with a slight lip. The septal sutures are well-marked.

Distribution.
The morphology of this species suggests that this species lived attached to the substrate, probably on the "seagrass" and on other substrates from reef environments of the inner shelf. This species is found in Ma-Da DS from Urbasa Pass section and in Se/Th-1 DS from Leortza section.

Superfamily: Loftusioidea brady
Description. The wall is agglutinated, thick with an alveolar texture. The apertures in nepionic stage are interiomarginal in position. The ephebic chambers have a uniserial arrangement.

Remarks.
The specific identification of this species has been left in open nomenclature since the nepionic stage could not been observed.
Distribution. This species has been found associated with M. minutus and T. madrugaensis.
Description. The test is agglutinated with discoidal morphology. In the material studied, the embryonic and nepionic stages could not be observed. The chambers of the ephebic stage are annular. The exoskeleton consists of beams and rafters, forming a polygonal network. Foramina are arranged in rows with radial axes in successive chambers.

Superfamily Ataxophragmioidea
Description. The test is agglutinated with high-conical morphology and cribrate aperture. The wall is thick and displays a pseudokeriothecal texture. The embryo could not be adequately observed. It is followed by chambers with trochospiral arrangement. The ephebic stage is composed of 8-10 chambers arranged uniserially. The apertural face is convex in early growth stages, becoming slightly convex or flat in the ephebic stage. The endoskeleton is composed of pillars arranged discontinuously from one chamber to the next. At a cone diameter of 0.9mm, the axial length is 1.2mm. The axial plane cuts 5-6 pillars in adult chambers. Chamber sutures are slightly depressed.

Superfamily Orbitolinoidea
Description. The test is agglutinated with high-conical morphology. The cone surface is smooth. The wall is thin without ultrastructure. The maximum cone-length observed is around 1.8mm with 15-16 uniserial chambers. The maximum diameter measured of an adult chamber is around 1.7mm. The embryonic stage has not been adequately observed. The nepionic stage is composed of chambers in trochospiral arrangement. The neanic stage consists of chambers arranged uniserially. There are 10-12 chambers per millimetre of axial length. The exoskeleton appears first in the neanic stage and consists of beams. The endoskeleton is composed of pillars with a subcircular horizontal section, except below the ceiling of the chamber where pillars have an elliptical shape in transverse section. Pillars alternate in position from one chamber to the next. The apertural face is slightly convex, and the aperture is cribrate.
Distribution. This species is present in the Se/Th-1 DS of the Campo section (Fig. 5), Tena section (Fig. 6), Leortza section (Fig. 12) and in Aixola-Ermua section (Fig. 14) with the species assemblage indicated in the aforementioned figures.
Biozone. This species was described by Mangin (1954) in the Paleocene from the Pyrenean basin. Later, Hottinger and Drobne (1980) and Serra-Kiel in Robador et al. (1991a, b) found it associated with G. primaeva, C. rajkae and V. anatolica, pointing it as a marker of the SBZ 3.  fig. 1-11; pl. 2, fig. 1, 3 1988 Cribrobulimina carniolica hottinger and drobne. Drobne et al.,pl. 26, fig. 10-11 Description. The test is agglutinated with low-conical morphology. The wall is thick with pseudokeriothekal texture. Chambers are inflated and arranged trochospirally. The sutures are strongly depressed. The apertures are interiomarginal in position in the early stage of growth, later becoming cribrate with multiple large apertures.
Description. The lamellar-perforated test is small, biumbilical, depressed with a planispiral involute chamber arrangement. The wall is thin. The chambers are inflated increasing in size through ontogeny. The apertures are located at the base of the apertural face.
Distribution. This species is present in the Da-1 DS from Tena section (Fig. 6). Da-2 DS from Urbasa Pass section (Fig. 11) associated with H. paleocenica, H. elongata and Goesella sp. and overlaying M. globularis and O. moorkensii. Finally, this species is also present in DA-1 DS and DA-2 DS from Urrobi section (Fig. 8).
Description. Small size, bilamellar-perforate test. The morphology is low-trochospiral with a rounded periphery. The ventral and dorsal sides have high convexity. The umbo is pronounced with a massive plug. The diameter of the proloculus is small (about 20µm). The diameter of the shell with 2 whorls is about 0.58mm and the height is 0.35mm.
Biozone. According to Hottinger (2014) and Vicedo et al. (2019) its biostratigraphic range is SBZ 2 to SBZ 3. J . S e r r a -K i e l e t a l . o l o g i c a A c t a , 1 8 . 8 , 1 -6  Material. Sample Cm 3 from Campo section (Fig. 5); sample L 26 from Lizarraga section (Fig. 10) and samples Ur 8 and Ur 10 from Urko section (Fig. 15).

G e
Description. Bilamellar-perforate test. The morphology is low-trochospiral with rounded periphery. The ventral side has high convexity. The umbo is pronounced. The diameter of the proloculus is around 60µm. The adult shell has a diameter of around 0.50mm with 3 whorls and a height of 0.33mm.
Distribution. This species is present in the Da-1 DS from Urko section (Fig. 15), Se/Th-1 DS from Campo section (Fig. 5) and in Lizarraga section ( Fig. 10) with the species assemblage indicated in the aforementioned figures.

Description.
Test with coarsely perforated wall. The morphology is lenticular with a trochospiral chamber arrangement and rounded periphery. The folia overlap the adaxial part of the umbilicus (Fig. 20). The diameter for 3 whorls is around 1mm and the height 0.45mm.
Description. Test with coarsely perforated, bilamellar wall and conical morphology. The chambers are arranged trochospirally. The dorsal side is smooth without ornamentation; the chambers sutures flush. The ventral side is covered by long and delicate folia. Umbilicus composed of piles and funnels. The diameter of the proloculus is around 110µm.
Distribution. This species has been identified in the Da-2 DS of the Lizarraga section ( Fig. 10) with the species assemblage indicated in the aforementioned figure.

Subfamily: Redmondininae
J . S e r r a -K i e l e t a l . o l o g i c a A c t a , 1 8 . 8 , 1 -6  Paleocene LBF from the Pyrenean Basin 38 Description. Bilamellar perforate shell with trochospiral chamber arrangement. The chamber wall shows coarse pores and rounded periphery. The umbilical filling is reduced with short and folded folia. The proloculus diameter is around 50µm. The diameter of the shell varies from 0.70 to 0.80mm with 3 whorls and the height from 0.40 to 0.50mm.

G e
Distribution. This species is present in the Se/Th-1 DS from Campo section (Fig. 5); Tena section ( Fig. 6) and in Leortza section (Fig. 12) and in the Th-2 DS from Korres section (Fig. 13) with the species assemblage indicated in the aforementioned figures.

Subfamily: Kathininae
Description. Bilamellar perforate specimens with trochospiral growth and lenticular morphology. The ventral side is more convex than the dorsal side ( Fig. 20I', M', P'). The test surface is smooth, without ornamentation. The umbilicus, with a structure typical of the Kathininae, shows a solid umbilical mass pierced by funnels (Fig. 20L', O'). Specimens show a small umbilical plate and a tiny spiral canal (Fig. 20O'). The proloculus has a diameter of 70µm. The diameter of the adult shell varies from 0.7 to 1mm with 2-3 whorls and the height from 0.5 to 0.6mm.

Biozone. K. aquitanica was characterized by
Hottinger (2014) and attributed to the SBZ 3. The presence of this species in the Da-2 DS in Aixola-Ermua section (Fig. 13) and in Urko section (Fig. 15) implies extending its biostratigraphic range from SBZ 2 to SBZ 4. Description. Bilamellar perforate, small-size test with low-trochospiral growth. The dorsal side is more convex than the ventral one ( Fig. 20Q'-R', V', 20W'). The solid umbilical structure is pierced by funnels (Fig.  20R', S', V'). The folia can be clearly observed (Fig.  20R', X'). The diameter of the proloculus is around 40-50µm (Fig. 20Q'). The adult shell has a diameter of around 1mm with 3 whorls and height of around 0.5mm.

Distribution. This species has been identified in the
Campo section (Fig. 4) in Se/Th-1 DS with the species assemblage indicated in the aforementioned figure.

Elazigina lenticula (hottinger, 2014)
Description. The test is bilamellar-perforated with trochospiral chamber arrangement. The morphology is lenticular with inflated umbonal area and rounded periphery. The dorsal and ventral sides have similar convexities (Fig.  21A, C-E, G-J). The adult shell has a diameter of around 1.6mm with 3 whorls and a height of around 0.95mm. The diameter of the proloculus varies from 0.130 to 0.160µm (Fig. 21A, E, I, K). The feathering of the intraseptal interlocular space is marked (Fig. 21C-D, F-H).
Distribution. This species is present in the depositional sequences Se/Th-1 DS from Andia section (Fig. 9) and in Lizarraga section (Fig. 10). It aslo occurs in the Th-2 DS from Korres section (Fig. 13) and in Aixola-Ermua section (Fig. 14) with the species assemblage indicated in the aforementioned figures.
Description. Large sized specimens with bilamellarperforated test and trochospiral growth. The morphology is typically subspherical with an angular but unkeeled periphery. The adult shell has a diameter that varies from 1.3-1.4mm with 2 whorls and height of around 1.20mm. The diameter of the proloculus is about 0.160-0.170µm in diameter (Fig. 21K, L).
Distribution. This species has been identified in Th-2 DS from Aixola-Ermua section (Fig. 14) with the species assemblage indicated in the aforementioned figure.

Biozone.
According Hottinger (2014) the biostratigraphic range of this species is SBZ 4, from which it can be considered a marker.  o l o g i c a A c t a , 1 8 . 8 , 1 -6  Description. The test is bilamellar perforate with trochospiral growth and sub-lenticular morphology. The dorsal side is decorated with beads and piles, while the ventral side shows an umbo with funnels. The equatorial diameter is around 1 mm with 19-20 chambers. The diameter of the proloculus is around 40µm.

Daviesina garumnensis tambareau, 1972
Description. The test is bilamellar perforate with lenticular morphology and trochospiral growth. The spiral growth pattern is alike the one of operculiniform foraminifera. Beads and piles can be found in dorsal and ventral sides. The equatorial length is 3.2mm and the thickness is 1.8mm for 15 chambers. The diameter of the proloculus of megalospheric forms is about 350µm.

Remarks.
This species is larger than D. praegarumnensis described by Hottinger (2014), which he considered a phylogenetic ancestor of D. garumnensis.
Biozone. The data presented here validate the biostratigraphic range of D. garumnensis as SBZ 4, from which it can be considered a marker, as previously proposed by Serra-Kiel et al. (1998) and Hottinger (2014). Two specimens architecturally close to Planorbulina: P.? antiqua and P.? cretae were identified in the material studied. The data presented below as well as the observations from other authors (Hofker, 1966;Hottinger in Peybernès et al., 2000;Pignatti in Accordi et al., 1998), suggest that a revision of the architecture of these species is needed in  o l o g i c a A c t a , 1 8 . 8 , 1 -6  Paleocene LBF from the Pyrenean Basin 42 order to clarify their generic attribution. The two species show significant architectural differences, especially as regard their ornamentation, which are of generic rank. Nonetheless, not enough material is available here to carry out such a revision. Fig. 23A-H 1960 Planorbulina antiqua. Mangin, p. 275, figs. 44ac 1972 Planorbulina cretae (marsson). Samuel et al., pl. 51, fig. 2 1969 Planorbulina cretae (marsson). Bignot and Larsonneur,pl.3, fig.6 Material. Samples Urb 1, Urb 2, Urb 3, Urb 4 from Urbasa Pass section (Fig. 11) and sample Ur 4 from Urko section (Fig. 15).

Planorbulina? antiqua manguin, 1960
Description. The test is bilamellar-perforate with flattened morphology. The wall is composed of a thin, perforate outer layer and a thin dark inner layer. The chambers show arcuate outline in axial section. The proloculus is spherical with a diameter of ca. 40-60µm (Fig. 23E, G). The apertures are located at the junction of chambers.
Distribution. This species has been identified in the depositional sequence Ma-Da DS from Urbasa Pass section (Fig. 11) and in Da-1 DS from Urko section (Fig. 15) with the species assemblage indicated in the aforementioned figures.

Planorbulina? cretae (marsson, 1878)
Description. The test is bilamellar-perforate with flattened morphology. The wall is composed of a thick, perforate outer layer and a thin, inner layer. Between the two layers, there is a dark median layer. In axial section, chambers show an arcuate outline. The proloculus is spherical with a diameter of around 100-120µm (Fig. 23L). The apertures are located at the junction of chambers.
Remarks. P. cretae differs from P. antiqua by the larger dimensions of the test, by having a thicker wall and by the presence of beads on the dorsal side.

Remarks.
Solenomeris was formerly considered as belonging to the red algae. Subsequently the studies of Perrin (1987Perrin ( , 1994 and Bassi (2003) concluded that it J . S e r r a -K i e l e t a l . o l o g i c a A c t a , 1 8 . 8 , 1 -6  should be ascribed to the acervulinid foraminifera. We refer the reader to these studies for further information about the architecture of this species.

G e
Distribution. The morphology of this species suggests a habitus attached to the "seagrass" and substrates of reef environments of the inner shelf. In the material studied this species was found in the depositional sequence Ma-Da DS and Se/Th-1 DS from Leortza section (Fig. 12) with the species assemblage indicated in the aforementioned figures.

Superfamily Discorboidea
Description. Low trochospiral test with slightly biconvex morphology. However, some specimens are almost flattened. The periphery of the shell is rounded. The wall is composed of a thick, hyaline outer layer and a dark inner layer. For three whorls, the equatorial diameter is around 1mm. The proloculus is spherical with a diameter of around 50-80µm ( Fig. 23O-Q, S). The dorsal side is smooth; some specimens show small beads (Fig. 23Q, R). Septa are inclined backward and the foramina are located in interiomarginal position (Fig. 23U).
Remarks. Samuel et al. (1972) and Sirel (1998) determined specimens similar to the specimens studied here as Mississippina binkhorsti (reuss, 1862). However, this species has been ascribed to the genus Stomatorbina by Hottinger in Peybernès et al. (2000), Pignatti in Accordi et al. (1998) and Sirel (2015). Being aware that the taxonomic determination of this species remains uncertain, we have ascribed it tentatively to the genus Stomatorbina.

Sistanites iranicus rahaghi, 1983
Description. Low-trochospiral test with biconvex morphology. The periphery of the shell is subacute. The wall is composed of a thicker, hyaline outer layer and a dark inner layer. For ten chambers, the equatorial diameter is 0.8mm. The proloculus is spherical with a diameter of around 100µm (Fig. 23C'). The dorsal and ventral sides ornamented with beads (Fig. 23C'). Septa are inclined. The foramina are cribrate, located in interiomarginal position in the septum.

Family Bagginidae cushman
Description. Lamellar perforate specimens with trochospiral growth and rounded periphery. The chambers are inflated and increase gradually in size. The dorsal side is flat to slightly convex; the ventral side has a depressed umbilicus. The sutures are slightly depressed. The aperture is simple and located in interiomarginal position. The diameter of the test for 14-17 chambers varies from 0.460 to 0.650mm and the thickness of adult tests is around 0.370mm. The diameter of the spherical proloculus is around 45µm.
Distribution. This species occurs in the depositional Sequence Ma-Da DS from the Urbasa Pass section (Fig.  11); in the Da-1 DS from the Aixola-Ermua section (Fig.  14) and in Urko section (Fig. 15) in the Da-2 DS from the Lizarraga section (Fig. 10) and Aixola-Ermua section (Fig. 14) with the species assemblage indicated in the aforementioned figures.

Diagnosis.
Wall finely perforated with low trochospiral growth and rounded periphery. Dimorphism not observed, probably restricted to early stages of growth. Chambers inflated and increasing gradually in size as added. Dorsal side flat; ventral side with depressed umbilicus. Aperture simple and located in interiomarginal position. Sutures slightly depressed. Embryo consisting of a spherical proloculus with a diameter of around 60µm (Fig. 23N'-P'). Adult specimens with a diameter generally of around 0.800mm but reaching up to 1mm (Fig. 23M') for 28 chambers and 3 whorls (Fig. 23O'). Thickness measured 0.441mm.

Remarks. See previous remarks on V. patalaensis concerning the generic attribution.
Distribution. This species is present in the depositional sequence Se/Th-1 DS from Campo section (Fig. 5), Lizarraga section (Fig. 10) and in Urbasa Pass section (Fig.  11). It also occcurs in the Th-2 DS from Korres section (Fig. 13). The species assemblage is indicated in the aforementioned figures.

G e
Description. The test is bilamellar with coarse pores and low-trochospiral growth. The dorsal side is pseudoinvolute, convex and smooth; the ventral side is slightly convex with an umbo with large beads (Fig. 23V', W'). The lamination is composed of a thicker and perforate outer layer and a thin, dark inner layer. The proloculus is spherical with a diameter of 100µm (Fig. 23S', T', W'). The equatorial diameter is 0.880mm with 20 chambers, and the thickness 0.490mm.
Description. Hyaline test with low-trochospiral growth (Fig. 23Z'). The chamber sutures are slightly depressed. In axial section, the periphery is carinate. The ornamentation consists of long and thin cross ridges producing a coarsely reticulate pattern in the test surface ( Fig. 23A''). In axial section, the ridges appear like spines (Fig. 23X', 23Z').

Remarks.
Due to insufficient material the determination of these specimens cannot be further refined.
Distribution. This species is present in the depositional sequence Da-2 DS from Lizarraga section (Fig. 10) and in Urko section (Fig. 15). It also occurs in the Se/Th-1 DS from and Campo section (Fig. 5) and in Urbasa Pass (Fig. 11) with the species assemblage indicated in the aforementioned figures.

Superfamily Nonionoidea
Description. The test is bilamellar perforate with planispiral growth. The lenticular tests are dimorphic and have a thick wall and rounded periphery. The ornamentation is dense and it is composed of piles and pustules. Megalospheric forms show a proloculus with a diameter of around 200-280µm. The equatorial diameter in megalospheric forms varies from 1.7 to 1.8mm and thickness between 1.0-1.15mm for 3 whorls. The microspheric form starts with a very small proloculus followed by chambers planispirally coiled, producing an adult test with an equatorial diameter of 2 mm and axial thickness of 1.6mm.
Distribution. This species is present in the Se/Th-1 DS in the Campo section (Fig. 5), Garralda section (Fig. 7) G e o l o g i c a A c t a , 1 8 . 8 , 1 -6

Y and Z axial sections.
A'-C' equatorial sections; D'-E' tangential sections. Specimens Y and D' from sample L 22; Z, A' and E' from sample Tap 15; B' and C' from sample L 21.

Miscellanea juliettae leppig, 1988
Description. Bilamellar-perforate, planispiral test. The shells are lenticular with thin wall; the periphery is acute without keel. The ornamentation is composed of beads covering the surface at the polar zone and abundant piles covering the lateral surface of the chambers. The megalospheric forms have an equatorial diameter that varies from 1.0 to 1.3mm with 3 whorls, and axial thickness of about 0.7-0.8mm. The megalospheric proloculus is about 160-230µm in diameter.
Distribution. This species is present in Se/Th-1 DS in the Urbasa Pass section (Fig. 11), the Leortza section (Fig.  12), the Aixola-Ermua section (Fig. 14) and in a sample taken from a pebble of the breccia located in TH-2 DS. The species assemblage is indicated in the aforementioned figures.
Description. The test is bilamellar perforate with planispiral growth. The morphology is spherical to ovoidal. The surface is covered with pustules. The equatorial diameter in megalospheric forms varies from 0.6 to 0.8mm with 3 whorls; the axial thickness is about 0.5mm. There are 3-4 piles at the polar zones. The protoconch is separated from the deuteroconch by a thin wall. The proloculus diameter varies from 70 to 100µm. Chambers have an isometric outline in equatorial section.
Biozone. The stratigraphic data and the associated foraminifera confirm the biostratigraphic range from SBZ 2 to SBZ 3 attributed by Hottinger (2009)

Biozone.
According to Hottinger (2009) the biostratigraphic range of this species is SBZ 3.
Description. The test is bilamellar perforated with planispiral growth. The shell is small with lenticular morphology and rounded periphery. In megalospheric forms, the equatorial diameter varies from 0.7 to 0.95mm, and axial thickness from 0.45 to 0.50mm. The ornamentation is composed of thick piles at the polar zone and fine piles on the lateral surface. The diameter of the megalospheric forms varies from 60 to 80µm. The septa are curved and inclined backward at the top of the chambers.
Distribution. This species is present in Se/Th-1 DS in the Campo section (Fig. 5), Andia section ( Fig. 9), Lizarraga section (Fig. 10) and in Urbasa Pass section ( Fig. 11) with the species assemblage indicated in the aforementioned figures.

GENUS: Ornatononion
Description. The test is bilamellar perforated with planispiral growth. The morphology of the shell is lenticular with acute poles. The ornamentation is composed of pustules and heavy piles in the polar zones. The megalospheric forms have an equatorial diameter that varies from 1.2 to 1.3mm, and axial thickness of around 0.6mm. The diameter of the proloculus of megalospheric forms is around 100µm.
Biozone. The stratigraphic data and the foraminifera associated with this species validate its biostratigraphic attribution to SBZ 2 as given by Hottinger (2009).
Description. The morphology of the microspheric and megalospheric form is flattened. The microspheric forms have a maximum equatorial diameter of ca. 1mm, while the megalospheric are around 0.6mm across. The spire is operculiniform, slightly irregular, opening rapidly. The ornamentation is composed of piles over the septa and between them. Diameter proloculus in megalospheric forms varies from 200 to 250µm. The septa are straight with dense distribution and recurved in the top of the chambers.
Remarks. This species was originally accommodated within genus Operculina. However, according to Tosquella (1995), a trabecular system can be observed in exceptionally well-preserved specimens from Narp, France (Tambareau et al., 1994a, p. 36), concluding that the species should be ranged in genus Nummulites. This feature is again illustrated here (Fig. 25.15).
However, by transferring the species to Nummulites, it becomes a junior secondary homonym of Nummulites heberti d' Archiac and Haime, 1853. As long as this controversy is not solved, the morphotype should be left in open nomenclature.
Description. The morphology of the microspheric forms is flattened with rounded periphery and slightly inflated at the polar regions. The test shows a diameter of 6.55mm for 5 whorls. The ornamentation consists of curved filaments and small piles over them in the polar zone. The spire is operculiniform tending to irregular assilinoid. The megalospheric forms show a flattened morphology, with a diameter of 3.3-3.5mm and thickness of around 1 mm for 3 whorls. The spire is regular and opens rapidly. Both generations show a thin marginal cord, and dense septa distribution. Septa straight and strongly recurved in the upper part of the chamber. The proloculus is small in megalospheric forms, with a diameter of around 120-150µm.

Distribution.
In the Le Quillet outcrop this species is associated with A. yvettae and A. azilensis, while in the Cérisols outcrop it is associated with A. azilensis.

Description.
The tests of the micro-and megalospheric forms show a flattened morphology, slightly inflate at the polar region and have a rounded periphery. The growth is evolute. The microspheric forms show an equatorial diameter of around 5.1 mm for 5 whorls and a thickness around 0.75mm in axial section. The megalospheric forms have an equatorial diameter of around 3.6mm for 3 whorls and a thickness around 0.7-1.1mm in axial section. In both generations, the spire is regular and opens rapidly. Septa are straight or slightly inclined and curved backward at the top of the chambers. The ornamentation consists of piles concentred at the polar zone. In megalospheric forms, the embryonic apparatus is isolepidine type. The diameter of the protoconch is 190-240µm and the deuteroconch has a length of 170-200µm in axial section and a height of 110-160µm.
Distribution. This species is identified in Th-2 DS in the following sections: Campo section (Fig. 5); Tena section ( Fig. 6); Urrobi section (Fig. 8); Urbasa Pass section (Fig. 11); Leortza section ( Fig. 12) and in Aixola-Ermua section (Fig. 14) with the species assemblage indicated in the aforementioned figures. In the Cérisols outcrop it is associated with N. catari and in the Le Quillet outcrop with A. yvettae and N. catari.

G e
Description. The microspheric forms show a flat morphology. The equatorial diameter is around 7.2mm and the axial thickness is around 1.3mm for 4 whorls. The megalospheric forms show a lenticular-flattened morphology with rounded periphery. In both generations, the growth is involute, becoming evolute in the last whorls. The ornamentation is composed of septal filaments and large piles at the polar zone. The septa are slightly curved. The marginal cord is thick. The proloculus in megalospheric forms has a diameter varying from 150 to 180µm.

Remarks.
Comparison of specimens of R. sindensis from the Paleocene of the Salt Range (Pakistan), those described here (Fig. 26P-Q) and those from Libya illustrated by Hottinger (1977), show that Ranikothalia sindensis differs from Ranikothalia soldadensis in the larger shell dimensions, the looser spiral, the larger diameter of the proloculus and the thinner marginal cord. Inconsistences related to genus Ranikothalia are discussed in more detail in Vicedo et al. (2014).
Distribution. This species is identified in Se/Th-1 DS in the following section: Urbasa Pass section (Fig.  11) and in Aixola-Ermua section (Fig. 14) where, in the the pebbles taken from a breccia in Th-2 DS, this species is associated with the species assemblage indicated in the aforementioned figures.

Family Discocyclinidae
Description. Small, lamellar perforate test with lenticular morphology. The equatorial diameter is about 1mm for 30-35 annuli and the thickness about 0.3mm. The embryonic apparatus is composed of a small protoconch and a deuteroconch. The diameter of the protoconch is around 0.1mm. The equatorial chambers increase in size towards the periphery.
Description. The test is bilamellar perforate with planispiral growth and non-symmetric equatorial morphology. The equatorial diameter varies from 0.5 to 0.6mm. The wall shows coarse pores. The dorsal side is flattened to slightly concave. The ventral side has parallel crests. The diameter of the proloculus is around 60µm.

GENUS
Description. Lamellar perforate test with subglobular morphology and trochospiral growth. The diameter of the proloculus is around 0.05mm. The dorsal side is flattened, the ventral side is markedly convex with rounded outline. For two whorls the equatorial diameter is around 0.6mm-0.7mm.
Distribution. This species is present in Campo section (Fig. 5) in Se/Th-1 DS with the species assemblage indicated in the aforementioned figures.
Biozone. The data obtained in this study validate the belonging of this species to the SBZ 3, as pointed out by Hottinger (2014).

Biostratigraphy based on Larger Foraminifera
Sixty species of larger foraminifera were found in the Pyrenean Paleocene with a biostratigraphic distribution belonging to the Tethyan SBZ 1 to SBZ 4. The new data led to a revision of the definition of these biozones, as proposed below.
Remarks on SBZ 1. According Serra Kiel et al. (1998), this biozone is characterized by the presence of Laffitteina bibensis and Bangiana hanseni as taxa defining the beginning of the Danian stage. According to our database, the use of these two species as markers need emendation.
Laffitteina bibensis is found in the Campo section together with the charophytes Peckichara llobregatensis and Sphaerochara edda attributed to the base of Paleocene (Fig. 5). Marie (1946) characterized these species from the Mont Aimé marls (Paris Basin) as being of Montian age. Later, Bignot (1987), Bignot (1993) and Bignot et al. (1997) also attributed the Vertus-Mont Aimé Fm. with Laffitteina bibensis (type locality) to the early Danian. However, the Paleocene age of the beds containing Laffitteina bibensis in Campo (sample Cm 1, Fig. 5) was first questioned by López-Martínez et al. (2006), who pointed out that these deposits underlie beds with rudists, the ammonite Pachydiscus gollevillensis and dinosaur remains. Finally, Guernet and Villier (2017), while studying the ostracods associated within the Mont Aimé Fm., considered that they were exclusively Cretaceous in age. Altogether, these data indicate that the attribution of the Laffitteina bibensis to the Danian should be rejected.
Bangiana hanseni was first described by Drobne et al. (2007) from the Danian of Slovenia. In the Pyrenees, this J . S e r r a -K i e l e t a l . o l o g i c a A c t a , 1 8 . 8 , 1 -6  Paleocene LBF from the Pyrenean Basin 58 species has been identified in the sections of Tena (sample Te 1; Fig. 6), Urrobi (samples Urrob 1 and Urrob 2; Fig. 8) and Urbasa Pass (samples Urb 2, Urb 12, Urb 16 and Urb 21; Fig. 11). In the Tena and Urrobi sections, this species is located in the Da-1 DS, while in the Urbasa section (Fig.  11), it is located in the Ma-Da Ds and Da-2 DS. In the Ma-Da DS Bangiana hanseni occurs associated with P.? antiqua, and Stomatorbina? binkhorsti, whereas in the Da-2 DS it is associated with Haymanella paleocenica, Haymanella elongata and Goesella sp. and overlying the beds with Miscellanites globularis and Ornatononion moorkensii indicating an SBZ 2 age.

G e
In the Urbasa Pass section, other species found in the lower and middle parts of the Danian, Ma-Da DS and Da-1 DS, are Valvulineria patalaensis associated with P.? antiqua, P.? cretae and Stomatorbina? binkhorsti (samples Urb 1, Urb 2, Urb 3 and Urb 4; Fig. 11). It is important to remark that Planorbulina? antiqua is located in our material in the stratigraphic interval belonging to the SBZ 1 (Urbasa Pass section, samples Urb 1, Urb 2 and Urb 3; Fig. 11) and in the lower part of the SBZ 2 (Urko section, sample Ur 4; Fig. 15).
In sum, Laffitteina bibensis is an exclusively Cretaceous species while the association of Bangiana hanseni, Miscellanites globularis and Ornatononion moorkensii does not allow anymore to propose the former species as exclusive of SBZ 1. This zone is thus characterized by the absence of the true larger foraminifera. Even the small foraminifera, such as P.? antiqua, Valvulineria patalaensis and S.? binkhorsti are not exclusive of this zone.
Paralockhartia eos, attributed to the SBZ 2 by Hottinger (2014), is also confirmed as a marker of SBZ 2 as it has been found associated with Haymanella elongata, Rotorbinella conica and Elazigina dienii in the Lizarraga section (Fig. 10) and in the Urko section (Fig. 15). Also Rotospirella conica belongs exclusively to the SBZ 2 and has been found associated with Haymanella elongata, Elazigina dienii, Daviesina praegarumnensis and Paralockhartia eos in the Lizarraga section (Fig. 10). The same situation is that of Pyrenerotalia depressa, which has been found exclusively in rocks attributed to the SBZ 2 in Urko section (Fig. 15) along with Rotorbinella hensoni, Rotorbinella skourensis and Ornatononion moorkensii.
On the other hand, some other associated species can no longer be considered as characteristic of SBZ2. Thus, Daviesina praegarumnensis extends from SBZ 2 to SBZ 3 according to (Hottinger, 2014), and it has been found indeed in beds attributed to the SBZ 2 in Lizarraga section (sample 3; Fig. 10) while in Campo section (samples Cm 3 and Cm 6; Fig. 5) it reaches the SBZ 3.
The SBZ 1 biozone can be correlated with calcareous plankton in the Aixola-Ermua and Monte Urko sections.
In Aixola-Ermua it encompasses the interval pertaining to the lower part of P1 zone (P1a+b subzones; Fig. 14), while in Monte Urko section, the SBZ 1 is correlated with the lower-middle part of calcareous nannoplankton NP2 or CNP2-partim CNP3 zones (Fig. 15). These data indicate that the top of the SBZ 1 is located within the upper part of NP2 zone, whereas its base at an indeterminate point within this zone. In the Aixola-Ermua section, SBZ 1 is correlated with the lower part of planktonic foraminifera zone P1 (P1a+P1b in Fig. 14).
The SBZ 2 biozone is correlated with calcareous nannofossils in the Urko section, in the interval comprised between the upper part of NP2 and the upper part of NP 4, or the lower part of CNP3 and the beginning of CNP7 (Fig. 15), and in part with P1c to P3 zones of the planktonic foraminifera in the Aixola-Ermua section (Fig.  14). Biostratigraphic data from the platform margin series studied by Baceta et al. (2005) document a correlation of the SBZ 2 with calcareous nannoplancton biozones spanning from the middle part of NP3 to the uppermost of the NP4. The discrepancy in the position of the base of the SBZ 2 as to that defined at the Monte Urko section most likely derives from the absence of shallow benthic foraminifera in the Da1 DS deposits exposed at Lizarraga pass section.
The biostratigraphic range of the species studied in this work is represented in Figure 28, in accordance with the International Chronostratigraphic Chart 2017 (Cohen et al. 2013;Vandenberghe et al. 2012).

CONCLUSIONS
Detailed taxonomic study of the Paleocene larger foraminifer from the Pyrenean basin has allowed us to identify sixty taxa, including two new species of larger J . S e r r a -K i e l e t a l . o l o g i c a A c t a , 1 8 . 8 , 1 -6  The present study has allowed us to redefine and recalibrate the SBZs of the Paleocene according to new correlation data with calcareous nannoplancton and planktnic foraminifera, as follows (Fig. 29):

G e
• SBZ 1. According to the results of this study, Laffitteina bibensis and Bangiana hanseni can be definitively ruled out as markers for SBZ 1, contrary to the indications in Serra-Kiel et al., (1998). The SBZ 1 has, therefore, no exclusive markers and is now redefined to be characterized by an assemblage composed of Valvulineria patalaensis, Stomatorbina? binkhorsti, Planorbulina? antiqua and Bangiana hanseni. This assemblage encompasses the interval between the K/Pg boundary and the upper part of the Danian desposits (Da-2 DS). SBZ 1 is constrained by the chronostratigraphic interval between the K/Pg boundary and an intermediate point between the CNP2-CNP3 and the NP2-NP3 boundaries, corresponding to the first appearance of the markers of the SBZ 2.
The main modifications of the biostratigraphic range of the Paleocene SBZ with the Serra-Kiel et al. (1998) are as follows (Fig. 29): • Reduction of the SBZ 1 range from 4.06m.y. to 1.09m.y. • Extension of the SBZ 2 range from 1.19m.y. to 3.34m.y. • Extension of the SBZ 3 range from 2+ • The SBZ 3 covers from the base of the Selandian to the middle part of the Thanetian. The SBZ 4 is late Thanetian.
Furthermore, the combined study of calcareous nannoplankton and larger foraminifera improve the correlation between the DS as defined by Baceta et al. (2004,2005,2011) and Schmitz et al. (2011), and the Geological Time Scale (Fig. 2). Thus the ages of these depositional sequences is as follows: Ma-Da DS is Maastrichtian−earliest Danian in age; Da-1 DS is early Danian; Da-2 DS is late Danian; Se/Th-1 DS is Selandian/early−middle Thanetian and Th-2 D is late Thanetian in age. o l o g i c a A c t a , 1 8 . 8 , 1 -6 Tosquella and Serra-Kiel, 1998