Palaeoenvironmental conditions preceding the Messinian Salinity Crisis: A case study from Gavdos Island

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Geobios 40 (2007) 251–265

Original article

Palaeoenvironmental conditions preceding the Messinian Salinity Crisis:

A case study from Gavdos Island

´ ´ ´ ´
Conditions paleoenvironnementales precedant la crise de salinite
messinienne : le cas de l’ıle Gavdos

Hara Drinia *, Assimina Antonarakou, Nikolaos Tsaparas, George Kontakiotis

Department of Historical Geology and Paleontology, Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens,

Panepistimiopolis, 15784, Athens, Greece

Received 20 January 2005; accepted 9 February 2007

Available online 23 April 2007

Abstract

The Messinian pre-evaporitic sedimentary succession of Gavdos Island (Metochia section) is a nearly uninterrupted succession of marine

sediments, dominated by finely laminated diatomaceous marls, which are cyclically alternating with clayey diatomites and white diatomites. The

qualitative and quantitative analysis of the planktonic foraminiferal fauna allowed the recognition of nine bioevents, which have been

astronomically dated for the Mediterranean. The base of the diatomitic succession in Gavdos Island is dated at 6.722 Ma and the top at

6.015 Ma. The studied section contains benthic foraminiferal genera characteristic of an outer shelf to slope environment. The qualitative and

quantitative analysis of this microfauna revealed three benthic foraminiferal fossil assemblages and the occurrence of allochthonous species

transported into the bathyal environment by current activity. The cyclical pattern of the benthic foraminifera assemblages indicates that the studied

sediments have been affected by repeated episodes of basin restriction characterized by low diversity benthic foraminifera populations, and a

limited planktonic foraminifer association typified by shallow, surface-dwelling forms. This restriction was partly due to Antarctic cooling, which

produced palaeo-Mediterranean sea-level oscillations during the Early Messinian, as a prelude to closure of the Atlantic connections. The relative

impact of climatic versus tectonic control on sedimentation patterns within this basin is discussed.

# 2007 Elsevier Masson SAS. All rights reserved.

Resume

Les sediments marins du Messinien pre-evaporitique de l’ıle de Gavdos (coupe de Metochia) sont quasi continus et domines par des marnes

diatomitiques finement laminees alternant de facon cyclique avec des diatomites argileuses et des diatomites blanches. L’analyse qualitative et

quantitative de la faune de foraminiferes planctoniques a permis la mise en evidence de neuf evenements biologiques qui ont ete dates par

l’astrochronologie a l’echelle de la Mediterranee. La base de la succession diatomitique de l’ıle de Gavdos date de 6,722 Ma et son sommet de

6,015 Ma. La coupe contient des genres de foraminiferes benthiques caracteristiques d’un environnement allant de la plate-forme externe au talus.

L’analyse qualitative et quantitative de cette microfaune revele trois assemblages de foraminiferes benthiques et la presence d’especes allochtones

apportees dans le domaine bathyal par l’activite des courants. Le caractere cyclique des assemblages de foraminiferes benthiques indique que ces

sediments ont ete affectes par des episodes repetes de confinement du bassin caracterises par la faible diversite des populations de foraminiferes

benthiques et une association restreinte de foraminiferes planctoniques marquee par des formes affectionnant les habitats de surface dans des eaux

de faible profondeur. Ce confinement etait en partie du au refroidissement antarctique qui entraına des oscillations du niveau marin de la

Mediterranee pendant le Messinien inferieur en prelude a la fermeture des corridors de connexion avec l’ocean Atlantique. Les impacts relatifs des

forcages du climat et de la tectonique sur les processus sedimentaires dans ce bassin sont discutes.

# 2007 Elsevier Masson SAS. All rights reserved.

Keywords: Benthic foraminifera; Messinian; Diatomaceous marls; Gavdos; Palaeoenvironment

Mots cles : Foraminiferes benthiques ; Messinien ; Marnes diatomitiques ; Gavdos ; Paleoenvironnement

* Corresponding author.

E-mail address: [email protected] (H. Drinia).

0016-6995/$ – see front matter # 2007 Elsevier Masson SAS. All rights reserved.

doi:10.1016/j.geobios.2007.02.003

mailto:[email protected]

http://dx.doi.org/10.1016/j.geobios.2007.02.003

H. Drinia et al. / Geobios 40 (2007) 251–265252

1. Introduction

In the Messinian, the isolated Mediterranean Sea subjected

to severe evaporation, resulting in a salinity crisis which had

worldwide implications (Hsu, 1972; Hsu et al., 1977). The

intense evaporation precipitated thick gypsum over almost the

entire Mediterranean and satellite basins, in the eastern and

western part, reflecting the extreme conditions that developed

in the Mediterranean region, known as the Messinian Salinity

Crisis (Selli, 1960; Hsu et al., 1973; Ryan et al., 1973;

Sonnenfeld, 1974; Cita et al., 1978).

In between 6.7 and 6.8 Ma time interval, a wide shift in

lithologies in the Mediterranean took place. Particularly, in the

Eastern Mediterranean, late Tortonian sapropels became

siliceous and were replaced by the diatomites of the Tripoli

Formation (Selli, 1960; Cita, 1975, 1976; Vergnaud Grazzini

et al., 1977; Pedley and Grasso, 1993; Suc et al., 1995;

Sprovieri et al., 1996; Hilgen and Krijgsman, 1999).

According to Hilgen and Krijgsman (1999) and Sierro et al.

(2001), the presence of cyclical diatomites is related to pre-

evaporite environments during the Messinian.

The increased biosiliceous productivity that resulted in

diatomites and preceded the salinity crisis in the Mediterranean

has been related to different factors, that is, upwelling of marine

Fig. 1. Simplified geological map of the Gavdos Island indicating the

Fig. 1. Carte geologique simplifiee de l’ıle de Gavdos indiquant

deep waters (McKenzie et al., 1980; Rouchy, 1982, 1986;

Muller, 1985; Muller and Hsu, 1987) or increase of the

terrestrial nutrients supply (Van der Zwaan, 1979; Hodell et al.,

1994; Rouchy et al., 1998).

Metochia section, in Gavdos Island, Greece (Fig. 1) provides

a continuous record of the latest Tortonian–early Messinian

environmental changes with a characteristically cyclic pattern.

According to Sprovieri et al. (1996), Hilgen and Krijgsman

(1999) and Krijgsman et al. (1999), sedimentary cycles are

mainly tripartite and are composed of a sapropel at the base,

followed by a prominent diatomite and a homogeneous layer on

top.

Many geological studies have been made on the lower pre-

evaporitic succession of the Metochia section, concentrating in

particular on the chronostratigraphy and the cyclical changes of

the microplankton population (Hilgen et al., 1995; Lourens

et al., 1996; Hilgen and Krijgsman, 1999; Triantaphyllou et al.,

1999; Sierro et al., 1999, 2001; Krijgsman et al., 1999, 2001;

Perez-Folgado et al., 2003). However, there is no published

comprehensive study of the benthic foraminifera fauna. Yet, a

few small-scale studies of the benthic foraminifera have been

made (Kouwenhoven et al., 1999, 2003; Seidenkrantz et al.,

2000). These have mainly concentrated upon the lower part of

the pre-evaporitic sequence (6.8–6.6 Ma).

location of the pre-evaporitic sequence of the Metochia section.

la localisation de la sequence pre-evaporitique de Metochia.

H. Drinia et al. / Geobios 40 (2007) 251–265 253

This study represents a thorough investigation of benthic

foraminifera found within the pre-evaporitic succession of the

Metochia section. In particular, benthic foraminifera are used to

estimate shifts in the energy regime and water mass properties,

as well as sediment supply, nutrification and oxygenation.

The area of study

The pre-evaporitic succession of the Metochia section

(Fig. 2) is only 14.5 m thick and consists of clayey diatomites,

white diatomites and diatomaceous laminated marls, locally

associated with marly limestones. Perez-Folgado et al. (2003)

used the term ‘‘sapropel’’ instead of ‘‘diatomaceous laminated

marls’’, yet these layers cannot be considered true sapropels,

since they are in fact thin, faintly laminated reddish layers that

mark the transition from the clayey diatomites to diatomites. At

about 12.7 m, the succession becomes enriched in layers of

medium grey limestones interbedded with clayey diatomites

and diatomaceous marls, without diatomites.

Fig. 2. Lithostratigraphical column of the pre-evaporitic sequence of the

Metochia section.

Fig. 2. Lithostratigraphie de la sequence pre-evaporitique de la coupe de

Metochia.

X-ray diffraction analyses in the diatomites (Triantaphyllou

et al., 1999) showed the mineralogical composition of the

sediments. Opal (amorphous silica) is the most important

component (concentration ranging from 36% to 65%),

reflecting the high content in siliceous phytoplankton skeletons.

The diatom assemblage is clearly dominated by Thalassionema

sp. (Perez-Folgado et al., 2003) that is a species characteristic of

the present-day low-intensity upwelling in the Mediterranean

(Abrantes, 1988; Barcena and Abrantes, 1998).

Among the diatom rests, unfragmented resting spores of

Chaetoceros sp. (Chaetoceros r.s.) are relatively abundant,

confirming the relevancy of the upwelling events driving

sedimentation processes. Therefore, the association of Chae-

toceros r.s. and Thalassionema can be related to strong seasonal

upwelling events (Rodrıguez and Escribano, 1996).

According to Gaudant et al. (2006), the ichthyofauna in the

Messinian diatomites of the Gavdos Island is strongly ruled over

by the mid-pelagic species of Myctophidae and Paralepididae,

which comprise 73% of the collected material. In particular,

Myctophidae attest the existence of deep zones of at least several

hundred meters deep, located along the margins of the

circalittoral zone. Important is also the occurrence of Maurolicus

muelleri, which typically lives in water depths of 100 to 500 m,

but has a daily migration status (depending on whether it is a

juvenile or not individual) between 150 and 250 m in the water

column. The occurrence of these species shows that the

sedimentation must have taken place in deep water. The

scattered occurrence of the species Syngnathus albyi and

Bragmaceros albyi in the same sediments, of which the

present-day representatives live in shallow waters, can be

explained only by the action of marine currents (Gaudant, 2002).

2. Material and methods

In total, 43 samples (D1-D43) were collected from the

studied section, from the clayey diatomites and the laminated

diatomaceous marls, which were processed for their calcareous

microfossil content.

Preservation of the material in these samples is, in most

cases, good with species determination, hard in just a few

samples. In these samples, recrystallization of the fossils and

mechanical deformation or dissolution of the tests impeded

determination.

In the majority of the 43 samples, the benthics are secondary

to the abundant planktonics.

2.1. Planktonic foraminifera

Planktonic foraminifera have been used for the biostrati-

graphic determination of the studied sequence. In order to

provide an accurate time spanning of the studied sediments and

to determine and calibrate the bioevents recognized, we

proceeded in a detailed qualitative and semiquantitative

analysis of the planktonic foraminifera, which were handpicked

and identified in the collected samples.

Moreover, a quantitative micropalaeontological analysis has

been performed on the 43 samples of the section studied. After

Table 1

Species used as input for the transfer function calculating bottom-water

oxygenation

Tableau 1

Especes introduites dans la fonction de transfert permettant de calculer l’oxy-

genation des eaux de fond

Oxyphilic Taxa

Cibicidoides brady Sphaerodina bulloides

Cibicidoides italicus Quinqueloculina sp.

Cibicidoides kullenbergi Spiroloculina depressa

Cibicides lobatulus Pyrgo oblonga

Cibicides refulgens Siphonina reticulata

Cibicidoides ungerianus Globocassidulina subglobosa

Cibicidoides wuellerstorfi Gavelinopsis lobatulus

Cibicidoides robertsonianus Gavelinopsis praegeri

Lenticulina sp.


washing and drying, the samples were sieved through 125 and

63 mm mesh. The greater than 125 mm size fraction was split

into aliquots, from which 300–500 specimens of planktonic

foraminifera were randomly picked. Each fraction was

analyzed for planktonic foraminifera at the species level. Their

specific identifications were conducted according to reference

publications (Dermitzakis, 1978; Kennett and Srinivasan, 1983;

Iaccarino, 1985; Hilgen et al., 2000).

Raw data of microfossils were transformed into percentages

over the total abundance and percentage abundance curves

were plotted. Species with phylogenetic affinities and similar

environmental significance were also grouped to better interpret

distribution patterns.

2.2. Benthic foraminifera

Counts of benthic foraminiferal species were made on splits

from the 125 mm fraction. Between 200 and 300 specimens of

benthic foraminifera were picked per sample, mounted on

Chapman slides, identified and counted. For each slide we also

counted the amount of planktonic foraminiferal specimens.

Samples with less than 30 benthic specimens were excluded

from plots and statistical treatments, as the low number of

specimens in some samples means risking a false over-

representation of certain species. Therefore, of the 43 samples,

eight samples have been disregarded.

P/B ratio, expressed as a calculation of P/(P + B) � 100 (the

percentage of planktonic foraminifera of the total

foraminiferal population) and relative abundances of benthic

species were calculated. Values of species diversity were

determined from Shannon-Diversity H(s) Index by means of

PAST (PAleontology STatistics) Program of Hammer et al.

(2001).

Standard SPSS software was used to perform statistical

faunal analysis on the relative percentage data. Unweighted

pair group R-mode cluster analysis using the cluster method

Between Clusters Linkage (Pearson correlation) was used to

produce a dendrogram classification of the 14 most common

species (total relative abundance) from which species groups

were selected. The same reduced data set was introduced into a

factor analysis, with the purpose of describing the major trends

in benthic faunal development. Unrotated factor scores of the

first three axes were considered.

Finally, we applied the oxygen transfer function of

Kouwenhoven and Van der Zwaan (2006) to the benthic

faunas of the pre-evaporitic succession of the Metochia section,

according to the formula:

[Oxygen content mMol/L] = 7.9602 + 5.95 [% oxyphilic

taxa]

We selected a group of calcareous oxyphilic species

(Table 1) in order to reconstruct the oxygen contents of the

bottom waters. Basically, we used the same species that were

used by Kouwenhoven (2000) for the estimation of bottom-

water oxygenation in the Monte del Casino section (N. Italy).

Agglutinated species were omitted because of the evident

fragility and rather low preservation potential of a number of

them.

3. Results and interpretations

3.1. Planktonic foraminifera faunal pattern and ecological

significance

The quantitative and qualitative analysis of the planktonic

foraminiferal fauna allowed the identification of 20 species

which were lamped into 12 groups (Fig. 3): Globigerinoides

obliquus/Globigerinoides apertura, Globigerinoides trilobus

group, Globigerina bulloides/Globigerina falconensis, Globi-

gerina obesa, Globorotalia scitula group, Globorotalia

conomiozea, Orbulina spp., Turborotalita quinqueloba, Tur-

borotalita multiloba, Globigerinita glutinata, Globoturborota-

lita nepenthes and Neogloboquadrina acostaensis.

These groups were introduced on the basis of morphological

characteristics of the species as the biostratigraphic and

palaeoenvironmental interpretations of their ecological features

do not change. Most of them are self-explaining but the labeling

of some of them needs further explanation. Different coiling

directions of the Neogloboquadrina acostaensis have been

counted separately as for the studied time interval coiling-

changes of this group have been proved to have potential

biostratigraphic significance. The distribution pattern of

selected taxa has been proved to be significant either for

biostratigraphic remarks, either for palaeoenvironmental

interpretation or both.

The Globigerina bulloides/falconensis includes the species

G. bulloides and G. falconensis. Small-sized specimens, under

poor preservation conditions, were difficult to distinguish,

while both species have the same ecological requirements. This

group exists in significant numbers in the lower part of the

section (up to 7 m) then vanishes for the interval 7–11.4 m and

reoccurs up to the top, reaching maximum abundance at

11.45 m. G. bulloides, is a cold intermediate species, indicating

cool, nutrient rich waters, often used as a good proxy for

upwelling (Thiede, 1983; Prell, 1984). Its distribution is

controlled primarily by variations in primary productivity

rather than by water temperature (Reynolds and Thunell, 1985).

The coexistence of this group together with the surface-

dwellers, G. obliquus/G. apertura, which are characteristic for

warm oligotrophic conditions and stratified waters (Be, 1977;

Fig. 3. Faunal abundance pattern and bioevents of the planktonic foraminifera.

Fig. 3. Motif d’abondance faunistique et evenements biologiques chez les foraminiferes planctoniques.


Be and Tolderlund, 1971; Hemleben et al., 1989), in the lower

part of the section (0–7 m), and the abundance of N. acostaensis

(sinistral forms), suggests high seasonal contrasts and high

primary productivity. G. obliquus/apertura occurs up to 7.12 m

and then its presence declines significantly till the top of the

section.

Neogloboquadrina acostaensis is a significant faunal

component being present in almost all the samples, being more

abundant in the lower part of the section. This species flourishes

in cool eutrophicated water suggesting a distinct DCM at that

time (Fairbanks and Wiebe, 1980; Fairbanks et al., 1982).

Significant peaks in abundance of Orbulina spp. indicate

warm oligotrophic waters, whereas this species is tolerant to

high salinity conditions (Bijma et al., 1990), being dominant

taxon in pre-evaporitic assemblages (Sprovieri et al., 1996;

Blanc-Valleron et al., 2002; Sierro et al., 2003).

However, low trophic levels, normal salinities and warm

waters are indicated by the elevated percentages of G. trilobus

gr. (G. trilobus and G. sacculifer) in the middle part of the

section (6.3–7.3 m).

The occurrence of T. multiloba has biostratigraphic

significance characterizing the Messinian Stage and assigns

certain environmental changes prevailed at that time, preceding

the MSC. This species which is considered to be a morphotype

of T. quinqueloba with more chambers in the final whorl is a

eurythermal species which eutrophicates under environmental

stress conditions. Turborotalita multiloba dominates the

planktonic foraminiferal assemblage in the interval from

7.12 to 11.85 m. There are levels with 60–100% dominance of

this species, making the assemblage monospecific at 7.8 m. Its

abundance has been related to the progressive isolation of the

Mediterranean Sea, increased salinity and cold superficial

waters (Sierro et al., 2003; Blanc-Valleron et al., 2002;

Kouwenhoven et al., 2006). Together with T. quinqueloba and

G. glutinata flourishes during low diversity intervals because of

nutrient availability and high salinity conditions (Sierro et al.,

2003). Consequently, the distinct interval, where T. multiloba

appears to be dominant, modifies the sequence by stress

environmental conditions, high salinities and cool surface

waters.

The distribution pattern of T. quinqueloba reveals several

peaks in abundance reaching maximum at 0.7 and 11.2 m

(>20%). The species is indicative for cold eutrophic waters

(Tolderlund and Be, 1971; Hemleben et al., 1989) as well as

tolerant to hypersaline conditions (Van de Poel, 1992).

G. glutinata is found in subarctic and subantarctic waters

and is related to stress conditions (Sierro et al., 1999, 2003). In

our record, its maximum abundance is found at 5.2, 5.4 and

11.4 m of the section (>10%).

3.2. Biostratigraphy

The planktonic foraminifera biostratigraphy of the pre-

evaporitic sequence of the Metochia section is based on the

quantitative analysis of the planktonic foraminifera and their

stratigraphic distribution pattern plus the coiling ratio of

Neogloboquadrina acostaensis (Fig. 3). The bioevents con-

sidered in this study are mainly based on changes in the

planktonic foraminifera assemblage observed in the fraction

greater than 125 mm and are accurately dated using the


astronomical calibrated time scale (Krijgsman et al., 1999;

Sierro et al., 2001).

The studied succession has been previously astronomically

calibrated to the Messinian by tuning the sedimentary cycle

patterns to variations of the Earth’s orbital parameters (Hilgen

and Krijgsman, 1999). The characteristic sedimentary cycles

have been correlated to the astronomical target curve, in

particular the precession/obliquity interference patterns in

isolation curve.

Nine planktonic foraminifera bioevents have been recog-

nized and are astronomically dated in other Mediterranean

sections. Six of these events have been first reported by Hilgen

and Krijgsman (1999). The chronostratigraphic framework

used here for the Messinian section is given in Table 2.

In the lowermost part of Metochia diatomites, the last

common occurrence of Globorotalia nicolae was observed just

below the first diatomitic layer and marks the onset of the

diatomitic sequence of Gavdos (6.696 Ma, Hilgen et al., 1995;

Krijgsman et al., 1995). The last occurrence (LO) of this species

has been dated in Metochia at 6.722 Ma (Krijgsman et al.,

1999) and was recognized in Abad composite section in SE

Spain, dated at 6.713 Ma (Sierro et al., 2001). In our record, G.

nicolae is included in the G. scitula group and its last

occurrence is observed at 0.28 m of the section. Above this

bioevent, the G. scitula group (dextral coiling specimens)

shows an abrupt reduction, recorded also in Upper Abad section

and in other Mediterranean sections (Hilgen and Krijgsman,

1999; Sierro et al., 2001). The distribution pattern of this group

up to the top of the section reveals some small influxes that can

be regarded as secondary bioevents. The influx reported at

10.27 m has been dated by Sierro et al. (2001) at 6.291 Ma.

Specimens of G. obesa are relatively common in our record

showing a prominent high abundance (20%) at 3.45 m of the

section. The first abundant occurrence of G. obesa was dated in

the Upper Abad section at 6.613 Ma (Sierro et al., 2001, 2003).

The last occurrence of Globorotalia conomiozea (6.506 Ma,

Hilgen and Krijgsman, 1999; 6.504 Ma, Sierro et al., 2001;

6.51 Ma, Blanc-Valleron et al., 2002) is observed at 6.10 m of

the diatomitic sequence in Gavdos recorded in cycle 11 from

Table 2

Planktonic foraminifera bioevents in the pre-evaporitic sequence of the Meto-

chia section (Krijgsman et al., 1999)

Tableau 2

Evenements biologiques chez les foraminiferes planctoniques de la sequence

pre-evaporitique de la coupe de Metochia (Krijgsman et al., 1999)

Bioevents Stratigraphic

level (m)

Age (Ma)

Globorotalia nicolae LO 0.28 6.722

Globigerina obesa FAO 3.45 6.613

Globorotalia conomiozea LO 6.10 6.506

Turborotalita multiloba FAO 7.12 6.415

Neogloboquadrina acostaensis d/s 8.85 6.360

Globorotalia scitula influx 10.27 6.295

N. acostaensis dominance sin. forms 11.45–11.85 6.140–6.108

N. acostaensis influx sin. forms 12.46 6.082

N. acostaensis influx sin. forms 13.55 6.015

LO, Last Occurrence; FAO, First Abundant Occurrence.

Krijgsman et al. (1999) in Metochia, which is in accordance

with our record.

The entry of Turborotalita multiloba is a significant bioevent

used for the correlations of the pre-evaporitic sequences in the

Mediterranean. The first common occurrence of this species is

dated at 6.415 Ma (Hilgen and Krijgsman, 1999; Sierro et al.,

2001; Blanc-Valleron et al., 2002) and is observed at 7.12 m of

our record. Short incursions of the species are recorded before

its common occurrence in our record.

A prominent sinistral to dextral change of the coiling direction

of the Neogloboquadrina acostaensis is located at 8.85 m of the

sequence, slightly above the thick diatomite bed (70 cm). This

coiling change is of great importance as it has been also recorded

in the pre-evaporitic marls of other Mediterranean sections and in

the North Atlantic (Hodell et al., 1994, 2001; Krijgsman et al.,

1999, 2002; Hilgen and Krijgsman, 1999; Sierro et al., 2001;

Blanc-Valleron et al., 2002). It is therefore astronomically

dated at 6.360 Ma. In the studied sequence, above this level the

dextral-coiled neogloboquadrinids dominate the planktonic

foraminiferal assemblages, whereas a prominent interval of

dominance of sinistral forms is observed at 11.45–11.85 m of the

section. Sierro et al. (2001) gave the age of 6.140–6.108 Ma for

this interval. On top of this interval, there is a peak in abundance

of sinistral forms at 12.46 m corresponding to the second influx

of sinistral neogloboquadrinids dated from Sierro et al. (2001) at

6.082 Ma and from Hilgen and Krijgsman (1999) at 6.087 Ma. In

our record, on top of the diatomitic sequence the influx of sinistral

neogloboquadrinids seems to correspond to cycle 48 of

Falconara/Gibliscemi composite section, dated at 6.015 Ma

(Blanc-Valleron et al., 2002).

Therefore, the accurate age of the planktonic foraminifera

events and their stratigraphic position demonstrate that the pre-

evaporitic studied sequence covers the interval from 6.722 to

6.015 Ma.

3.3. Benthic foraminiferal trends and palaeoenvironmental

significance

In total, 4536 benthic foraminifera specimens, belonging to

83 different species, were picked and identified from the pre-

evaporitic sequence of the Metochia section. Within this

sequence, agglutinated foraminifera are extremely rare as it is

common in the Messinian deposits. As far as the porcelaneous

foraminifera are concerned, these are also represented by very

low numbers. The distribution of dominant, common or

significant species, which characterize the benthic foraminif-

eral fauna of the studied succession, is reported in Fig. 4.

The most frequent species of the benthic foraminiferal fauna

are: Bolivina plicatella, Bolivina spathulata group (including

B. spathulata, B. dilatata, B. tortuosa), Bulimina aculeata

group (including B. aculeata, B. elongata, B. lappa), Elphidium

spp., Asterigerinata planorbis and Gyroidinoides neosoldanii.

Additional and significant species are Anomalinoides spp.,

Cibicidoides spp., Melonis sp., Uvigerina spp. and Valvulineria

bradyana.

Trends in the relative abundance of different taxa are likely

to be responses to palaeoenvironmental changes, such as

Fig. 4. Faunal abundance pattern of benthic foraminifera.

Fig. 4. Motif d’abondance faunistique chez les foraminiferes benthiques.


changes in the abundance and character of organic food flux, or

changes in the stratification depths or character of the different

deep-water masses (e.g. Jorissen, 1999). As a consequence, we

discuss the distributional pattern of the encountered taxa in

relation to their life strategies and to these environmental

factors.

Bolivinidae and Buliminidae dominate throughout the

succession, strongly fluctuating in the range of 0.5–79% and

1–98%, respectively. These taxa practice an opportunistic life

strategy, and are able to tolerate periodic reductions in

dissolved oxygen contents by modifying their microhabitat

from infaunal to epifaunal (Jorissen et al., 1992; Kaiho, 1994).

Among the Bolivinidae, B. plicatella and B. spathulata

group species, are the most common.

Bolivina plicatella is relatively abundant in the basal part of

the section, displaying peak occurrences at 0.08 and 3.9 m (76.5

and 64.6%, respectively). According to Van der Zwaan (1982)

and Jonkers (1984), Bolivina plicatella is associated with mild

dysoxia and moderately elevated salinity. As said by

Seidenkrantz et al. (2000), the very poor benthic foraminiferal

fauna, with dominance of B. plicatella, at the base of the pre-

evaporitic succession of the Metochia section, is a result of the

increase in salinity, which may reflect the gradual formation of

deep brine caused by the diminishing of the Mediterranean–

Atlantic water exchange.

In the middle and upper parts of the succession, B. plicatella

is replaced by B. spathulata group. Bolivina spathulata group

displays its highest percent value at 8.25 m (52.61%). This

group of species connotes ecological stress, which is linked to

the presence of low oxygen values in the bottom water (Murray,

1991a). In particular and according to Van der Zwaan (1982),

Verhallen (1991), Jorissen et al. (1992), Kaiho (1994), Loubere

(1996, 1997), Bolivina spathulata group tends to increase when

the influx of terrigenous organic matter dominates the

environment. It shows opportunistic behaviour and a tolerance

to dysoxia, but also to elevated bottom water salinity. Yet, along

with Phleger and Soutar (1973), Sen Gupta et al. (1989), Caralp

(1989) and Gooday (1993), benthic assemblages dominated by

Bolivina spp. illustrate low oxygen environments with a

continuous flux of organic matter in regions of high

productivity, often associated with intense upwelling.

Bulimina aculeata group shows a fluctuating pattern

throughout the succession, reaching its highest frequency at

1.4 m (98%). Bulimina aculeata is an opportunistic deeper

dwelling species, not particularly dependent on high amounts

of fresh and unaltered organic matter, but certainly thriving

under a high organic flux (Gupta, 1997; Kawagata, 2001). In the

Mediterranean Sea, this species requires relatively eutrophic

bottom conditions (de Rijk et al., 2000). The highly shifting

abundances of Bulimina aculeata, observed in some samples

(Fig. 4) may reflect cyclic changes in sediment input and/or

circulation.

Gyroidinoides neosoldanii is only present in the lower part

of the record, displaying its highest occurrence at 0.7 m (68%).

In the rest of the record, it is almost absent. This opportunistic

species, considered to be epifaunal- to shallow- infaunal, is

commonly recorded before and during anoxic events (e.g.

Erbacher et al., 1998, 1999). It apparently thrives under meso to

Fig. 5. Dendrogram based on R-mode cluster analysis by means of SPSS

program.

Fig. 5. Dendrogramme base sur une analyse de groupements en mode R par le

programme SPSS.


eutrophic conditions, but is described as having low tolerance

for oxygen-poor environments (Coccioni and Galeotti, 1994;

Erbacher et al., 1999, 2001). According to Kaiho (1999), the

genus Gyroidinoides is considered to be a suboxic indicator.

The predominance of G. neosoldanii hence seems indicative of

moderately oxygenated, mesotrophic environments.

Cibicidoides kullenbergi, which is the main representative of

Cibicidoides spp. group, is strongly present in the middle part

of the succession, from 5.1 to 6.94 m, and then shows

fluctuating but diminishing abundance pattern up to the top of

the section. This species is widespread in well-ventilated and

oligo-mesotrophic conditions (Schmiedl et al., 2003) and it is

reported as not tolerating environmental stress, especially

oxygen deficiency at the bottom (Van der Zwaan, 1983).

From the rest of the species, Melonis sp., Uvigerina spp.,

Anomalinoides spp. and Valvulineria bradyana are represented

along the succession with fluctuating pattern and comparatively

low frequency values.

Uvigerina spp. and Melonis sp. are shallow infaunal species

characteristically found on continental slopes (Murray, 1991a,

1991b) in areas where there are persistently high organic carbon

inputs (Fariduddin and Loubere, 1997). Melonis sp. is

especially abundant in areas with high food supply (Corliss,

1985, 1991; Gooday, 1986; Corliss and Emerson, 1990;

Jorissen et al., 1998). There are some data showing a diffuse

distributional pattern of Melonis, altering between epifaunal

and deep infaunal maxima (Jannink et al., 1998), and seasonally

varying vertical distributions (Linke and Lutze, 1993),

signifying that this species is very mobile and changes habitats

as a response to varying food availability or altering

environmental conditions. Yet, consistent with Caralp

(1989), Melonis most likely prefers altered organic matter,

and consequently has a preference for deeper layers.

According to Altenbach and Sarnthein (1989), the micro-

habitat of Uvigerina species is characterized by elevated

concentrations of bacteria, exoenzymes and meiofauna, and is

typical of sediments enriched in organic carbon and depleted in

oxygen, as found in areas below upwelling productivity. As

reported by Thomas (1980), Van der Zwaan (1982, 1983), Van

der Zwaan and den Hartog Jager (1983) and Jonkers (1984),

U. cylindrical gaudrynoides, which is the main representative

of the Uvigerina spp. group in our record, proliferates

extremely under oxygen depletion.

Valvulineria bradyana seems to be excellent marker of high

benthic productivity, which is often related to moderate

environmental stress (Verhallen, 1991), whereas Anomali-

noides spp. thrives in mesotrophic conditions at outer shelf-

upper bathyal depths (Kouwenhoven, 2000).

Elphidium spp. and Asterigerinata planorbis are highly

abundant throughout the succession, especially in the middle

part (from 6.94 to 7.25 m), where they exceed 50% of total

abundance. These species are reported to live in shallow shelf

areas generally above 200 m (Seidenkrantz et al., 2000), but

they are also found in greater depths to which they are often

transported passively. They belong to the epiphytic taxa (e.g.

Seidenkrantz et al., 2000), whereas Murray (1991a) describes

non-keeled species of the genus Elphidium as infaunal, thriving

free in mud and sand on the inner shelf. These species are

extremely tolerant and adaptable to large variations in

temperature, salinity and food supply (Linke and Lutze,

1993). The abundance of these species is considered as an

indication of erosional processes from shallow shelf seas and

therefore not a part of the fossil community.

3.4. Benthic foraminifera assemblages

Inspection of the R-mode cluster analysis dendrogram

(Fig. 5) allows the identification of four benthic foraminiferal

groupings:

Cluster I represents a mixed fauna composed of allochtho-

nous taxa (Elphidium spp., A. planorbis) alongside abundant

and clearly autochthonous deeper water taxa (H. boueana,

Cibicidoides spp., Melonis sp. and Valvulineria bradyana).

This fauna may represent the bedload transport of (turbidity)

currents, sweeping material off the shelf into bathyal depths.

Therefore, this specific assemblage, dominated by almost

epibenthic species, is discussed as a possible current indicator.

Cluster II consists of B. spathulata group (max abundance

65%), Uvigerina spp. and Anomalinoides spp. The association

of Cluster II consists of species with shallow infaunal

microhabitat and adapted to live in environment with oxygen

depletion in bottom and pore water and with meso-eutrophic

conditions (Murray, 1991a, 1991b; Schmiedl et al., 2003).

Cluster III groups B. plicatella with G. neosoldanii. These

epifaunal to shallow infaunal species, which dominate in the

basal part of the succession, seem indicative of moderately

oxygenated, mesotrophic environments. However, as it is seen

from Fig. 4, B. plicatella and G. neosoldanii exhibit

complementary patterns of relative abundance. This rather

documents the different kind of stress that the two species may

represent. The occurrence of the benthic foraminifer

B. plicatella in the diatomaceous marly intervals is believed

to indicate raised salinities (Jonkers, 1984; Seidenkrantz et al.,

2000). Therefore, the predominance of B. plicatella against

Gyroidinoides may indicate a temporal increase in salinity.

Fig. 6. Cumulative plots of the four clusters in the pre-evaporitic sequence of the Metochia section, faunal diversity [H(s)], bottom-water oxygen contents,

reconstructed with the transfer function, P/B ratios together with factor scores. Dashed lines indicate the five time intervals of poor oxygenation during deposition of

the studied succession.

Fig. 6. Diagramme cumulatif des quatre groupements dans la sequence pre-evaporitique de la coupe de Metochia, diversite faunique [H(s)], contenu en oxygene des eaux

de fond, reconstruits par la fonction de transfert, rapport P/B avec les scores factoriels. Les traits soulignent les cinq intervalles a faible oxygenation reperes dans la coupe.

Table 3

Factor loadings for the benthic foraminiferal species from the pre-evaporitic

sequence of the Metochia section, imported into statistical analysis

Tableau 3

Scores factoriels des especes de foraminiferes benthiques dans la sequence pre-

evaporitique de la coupe de Metochia

Species Factor 1 Factor 2 Factor 3

Bulimina aculeata S0.78 0.14 0.30

Anomalinoides sp. 0.36 0.61 �0.34

Asterigerinata planorbis 0.37 S0.63 �0.19

Cibicidoides spp. 0.73 �0.05 0.33

Elphidium spp. 0.76 �0.18 �0.36

Gyroidinoides neosoldanii �0.11 �0.13 0.18

Hanzawaia boueana 0.68 �0.04 0.21

Melonis sp. 0.55 0.25 0.59Bolivina plicatella �0.04 �0.34 �0.15

Bolivina spathulata �0.17 0.75 �0.25

Uvigerina spp. 0.38 0.36 S0.50Vavulineria bradyana 0.34 0.44 0.45

In bold: the highest negative and positive scores.


Cluster IV consists only of B. aculeata group reflecting

conditions of enlarged food availability and lowered oxygen

concentration.

In Fig. 6, the cumulative plots of the four assemblages are

shown. They are plotted with the graphic trends of faunal

diversity [H(s)], bottom-water oxygen contents reconstructed

with the transfer function and P/B ratios.

R-mode Principal Component Analysis (PCA) was per-

formed on the correlation matrix using the SPSS software

package. Based on a screenplot of eigenvalues and viewing of

the factor scores (Table 3) and species associations, three

factors were considered that account for 53.5% of the total

variance (Fig. 6). Factors that do not show appropriate species

associations were not considered to make out assemblages.

Factor 1 is negatively loaded by Bulimina aculeata, whereas

species contributing to the positive scores on Factor 1 are

Elphidium spp. and Cibicidoides spp. which represent a mixed

foraminifera assemblage. Fig. 6 shows that Factor 1 is in good

correlation with Shannon diversity. The good correlation

between Factor 1 and general faunal characteristics indicates

that Factor 1 discriminates between two distinctly different

assemblages: (1) a high-diversity assemblage, of which the

species are positively loaded on Factor 1, indicating that the

ecosystem offers a habitable life for many more benthic species

with both an infaunal and epifaunal lifestyle, and (2) a low-

diversity assemblage, made up of species with negative

loadings, which indicates a specific, restricted environment

with stressed conditions (oxygen depletion, unusual tempera-

tures, low or high salinity and their large variations).

Factor 2 is positively loaded by B. spathulata group which

indicates high nutrient flux, often associated with upwelling

(Phleger and Soutar, 1973; Sen Gupta et al., 1981; Caralp,

1989; Gooday, 1993). Asterigerinata planorbis is loading

negatively Factor 2 suggesting transport of shallow-water

sediments to deep environment. Fluctuations in Factor 2 scores

thus reflect the different and alternating environmental

mechanisms responsible for deposition.

The associations loading Factor 3 do not bring any interesting

information likely to explain the factor. This phenomenon can be


interpreted in two different ways: either these species agree to

live under very varied environmental conditions (eurytype

species) or they require a whole set of very strict but intermediate

factors (stenotype species living in an environment of average

depth, oxygenation, productivity and salinity). Therefore, the

interpretation of this factor needs additional investigation with

more quantitative analysis involved.

3.5. Depth of the water and percentage of planktonic

foraminifera

The bathymetric preferences of the different foraminiferal

taxa were assessed by evaluating their distribution pattern in

modern oceans. Based on this information, the bathymetric

evolution at the investigated site can be reconstructed. The

benthic assemblages in almost all the samples have an upper to

middle bathyal aspect, being dominated by B. aculeata and B.

spathulata. Nine samples, however, yielded benthic assem-

blages that were dominated by Elphidium spp. and A. planorbis

associated with a lesser Cibicidoides spp. and Melonis sp. The

normally shallow-water preferences of Elphidium species

(Hayward et al., 1997) and A. planorbis (Murray, 1991a,

1991b) suggest that these samples were deposited at neritic

paleodepths and not at the bathyal paleodepths suggested by the

abundant planktonics. Furthermore, benthic foraminifera

typical of deep-water habitats, such as were recorded in the

rest of the samples, were also recovered from these samples, yet

in small percentages. Thus the presence of specimens from

Elphidium species and A. planorbis in fossil bathyal

assemblages should be explained by sediment displacement

(e.g. Phleger et al., 1953) or rafting of plant material to which

epiphytes lived attached into pelagic environments after storms

(Sprovieri and Hasegawa, 1990).

The percentage (%) of planktonic foraminifera is one of the

most consistent proxies to assess palaeo-water depths. It has

been known for a long time that the percentage of planktonic

foraminifera in modern sediments increases with water depth

(e.g. Boltovskoy and Wright, 1976; Gibson, 1989; Van der

Zwaan et al., 1990, 1999). Gibson (1989) suggested that the

relative difference between the higher rate of reproduction of

planktonic species in open ocean areas and the higher rate of

reproduction (density) of benthic species in neritic areas is the

main reason for the distribution observed. Furthermore, the

composite pelagic ecosystem requires a minimum water depth

(the entire photic zone at least) to be fully functional (Van der

Zwaan et al., 1990). Consequently, the density of planktonic

foraminifera depends on the proximity to open oceanic realms

(Gibson, 1989). Van der Zwaan et al. (1990, 1999) and Leckie

et al. (1998) emphasized the significance of nutrients for the P/

B ratio, in particular for benthic foraminifera. The percentage

of benthic foraminifera is inversely proportional to depth

because their rate of reproduction depends on the amount of

organic matter reaching the sea floor. Because the density of

planktonic and benthic foraminifera depends on the organic

flux, and the amount of organic matter reaching the sea floor

decreases with increasing water depth because of oxidation, the

P/B ratio as anticipated has to increase with depth (Van der

Zwaan et al., 1999). Other parameters such as temperature,

salinity, substrate or circulation patterns may play a minor role.

In our record, the benthic and planktonic foraminifera relative

abundance (P/B-ratio, Fig. 6) ranges between 0 and 94%. A

simple interpretation of this ratio using modern analogies (e.g.

Gibson, 1989) points to very rapid changes in water-depth

between inner shelf and lower bathyal, which is very unlikely and

not supported by any other evidence. Hence, the ecologic reason

for these enormous differences cannot be water-depth alone.

High fluctuations in the P/B ratio are interpreted as unstable

conditions in the upper water layers. However, an increasing

oceanic influence is implied by the increasing content of

planktonic foraminifera. As bottom-water stress is developing,

the P/B ratios are no longer reliable paleodepth-indicators, since

declining benthic faunas could erroneously suggest apparent

deepening (Van der Zwaan et al., 1999).

Moreover, the high %P (>90%), observed in a number of

samples does not seem realistic when compared with the

benthic assemblages, which suggest that the palaeodepth of the

succession studied was rather stable at around 300–500 m.

On the other hand, the abrupt declining of the P/B ratio in

some intervals of the record may merely reflect periodic

dilution of the autochthonous deep-water fauna with trans-

ported shallower faunas (e.g. Robertson, 1998). It is likely that,

in these beds, some degree of faunal reworking has occurred,

displacing shallow water taxa into deeper water faunas.

3.6. Environmental stability

Species diversity is recognized as a measure of environ-

mental stability. It can be viewed as a gross measure of the

effect of environmental stress on benthic foraminiferal

communities. Diversity of benthic foraminifera is determined

by an interplay of several parameters, among which nutrient

availability, temperature and changes in ocean circulation are

very important (Gage and Tyler, 1991).

According to Murray (1991a, 1991b), in open marine outer

shelf to slope environments, Shannon diversity is in the order of

3. Any gross deviation from this number indicates departure

from stability conditions: in this sense diversity is an

outstanding marker of stress in the benthic environment

(Boltovskoy and Wright, 1976; Murray, 1991a). As soon as

stability conditions at a site are disturbed, diversity will reduce

and certain species may begin to dominate the assemblage

(Kouwenhoven, 2000; Den Dulk et al., 1998). When the

Shannon diversity falls below 2, the balance in the assemblages

is distorted by high dominances of few stress tolerant taxa. In

general, foraminiferal species diversity is much lower in

stressed environments (e.g. Schafer et al., 1991; Samir, 2000).

The diversity (Shannon Index) of the benthic foraminifera in

our record is low in almost half of the studied samples (Fig. 6)

and considered alone may just indicate a brackish or

hypersaline marginal environment (Murray, 1991a, 1991b).

But as the diversity is higher in some layers, its relative

fluctuation can be used for further interpretations.

According to Fig. 6, the lowest values of the Shannon

diversity Index coincide with the peak occurrences of the B.


aculeata assemblage whereas the allochthonous assemblage

denotes higher diversity values due to the settling out of

allochthonous species transported into the bathyal environment

from shelf environments, by (turbidity) currents.

The low-diversity, dwarfed benthic foraminiferal faunas

(B. aculeata assemblage and B. spathulata group assemblage),

are indicative of faunas thriving under severe dysoxia, when

sustained organic carbon flux and high surface productivity

resulting from intensified upwelling and/or river runoff was

brought about (Zobel, 1973; Lutze and Coulbourn, 1984;

Hermelin and Shimmield, 1990; Denne and Sen Gupta, 1991;

Sen Gupta and Machain-Castillo, 1993; Jannink et al., 1998),

whereas the high-diversity fauna (allochthonous) suggests

higher bottom-water oxygen concentrations. In our record, this

assemblage contains about 60% shallow-water forms which

might have been reworked from the shelf/uppermost slope,

although the good preservation and the lack of sorting argue

against downslope transport by currents. It seems therefore

more likely that during periods of improved oxygen conditions

at the sea floor, species from shallower sites move downslope

and invade the formerly stressed environment.

3.7. Oxygenation

The result of the oxygen transfer function as applied to data

from the pre-evaporitic sequence of the Metochia section is also

presented in Fig. 6. This curve depicts the calculated oxygen

content at the sediment-water interface. The reconstructed

oxygen record represents the variation of the oxygen contents at

the sediment-water interface, and suggests that the actual

concentrations were moderate to high (ranging from 100 to

500 mMol/L). However, in five stratigraphic intervals, oxygen

levels dropped to values below 100 mMol/L. These five time

intervals of reduced bottom water-oxygenation are related to

decreasing species diversity and episodically increasing

amount of certain paleoecological (ventilation, salinity) key

groups (B. aculeata and B. spathulata assemblages).

4. Discussion

Benthic foraminiferal assemblages identified for the studied

succession provide information used to reconstruct the impact

of changing palaeosalinity, palaeooxygenation, palaeotransport

and palaeohydrodynamics. Four assemblages of benthic

foraminifera were recognized, each one conveying different

palaeoenvironmental information. They thus record a number

of fundamental changes in the environmental and water mass

characteristics of the Metochia Basin.

Benthic foraminifera assemblages document (cyclic) fluc-

tuations by decreasing species diversity and episodically

increasing amount of certain palaeoecological (ventilation,

salinity) key groups. More specifically the whole section is

characterized by five prominent abundance peaks of the

monospecific B. aculeata assemblage. Between the B. aculeata

peaks are samples dominated by the mixed faunal assemblage

and the B. spathulata assemblage which exhibit complementary

patterns.

4.1. Palaeoenvironmental implications

During the deposition of the pre-evaporitic Metochia

section, repeated restricted conditions influenced the studied

sediments which are well-expressed in the benthic foraminif-

eral assemblages. The repeated restriction of the basin was

punctuated by more adverse conditions at 6.7 and 6.4 to 6.1 Ma,

where prominent peaks in abundance of B. aculeata and

B. spathulata assemblages prevailed. During these time

intervals, the location was barred from direct Mediterranean

access by shallower-water sills, and may have contained

stratified water bodies with denser brine layers at depth. This is

a very common scenario which has been well-documented in

the Sicilian basins (e.g. Suc et al., 1995; Pedley and

Maniscalco, 1999). Such basins are characterized by ‘‘oligo-

typic faunas’’ (low diversity benthic foraminifer populations,

and a limited planktonic foraminifer association typified by

shallow, surface-dwelling forms such as Orbulina universa and

high frequencies of small-sized Turborotalina multiloba, T.

quinqueloba, Globigerinoides glutinata, Globigerinata uvula,

and Globigerina bulloides). The sparse benthic community

dominated by Bulimina aculeata and Bolivina spathulata is

attributed to periodically enhanced salinity.

Peaks in Elphidium spp. and A. planorbis (allochthonous

taxa), found in epibathyal environment, represent material

transported by lateral advection. This transport may reflect river

discharge, assuming that increased discharge is matched by an

increased transport of allochthonous littoral taxa into the deeper

basin. Salinity decreases are thought to reflect increased fluvial

discharge or runoff into the basin, which resulted in the

development of this mixed faunal assemblage.

The environment therefore experienced extreme changes in

nutrients and salinity depending on the extension of evaporation

versus freshwater input.

The study of the calcareous plankton and the benthic

foraminifera made possible to precise the palaeoenvironment

of the pre-evaporitic sediments in the Metochia section and led

us to moderate the notion of a progressive decrease of the water

depth of the basin. Indeed, significant shallowing of the

Metochia Basin prior to the Messinian Salinity Crisis has not

been documented. On the contrary, during the deposition of the

pre-evaporitic sediments of the Metochia section, the

palaeodepth remained relatively constant, around 300–

500 m with small scale fluctuations. A similar case has been

also certified in the Pissouri section, in Cyprus, where

Kouwenhoven et al. (2006) realized that the percentage of

planktonic foraminifera (%P) is of minor value for depth

reconstruction due to basin restriction, and controlled by

factors other than palaeodepth. This is evident for the time

interval from 6.4 Ma onwards where the restricted conditions

are more pronounced.

4.2. Tectonic or climatic controls

The varied faunal pattern responses mentioned before are

not random, but provide the key to unlocking the broader

question as to whether the depositional patterns within the


Metochia Basin were driven by tectonic or climatic (eustatic)

change.

It is frequently difficult to separate the contributory

effects of tectonic and climatic change as they usually act in

concert.

The most likely cause of the repeated basinal isolation is a

recurring shallowing of the sill-depths over which the basin

receives its bottom water. Assuming a silled configuration of

the Metochia Basin and evaporation exceeding precipitation, a

minor drop of sea level could either restrict or completely block

inflow and/or outflow and result in evaporative drawdown,

thereby increasing the salinity. The restriction of the environ-

ment was related to the continuous tectonic events which

affected the Eastern Mediterranean Basin and the progressive

closure of the connection between the Mediterranean Sea and

the Atlantic Ocean, together with changes in the climate

(Orszag-Sperber et al., 1980; Robertson et al., 1995; Merle

et al., 2002; Rouchy and Caruso, 2006). Marine waters suffered

a progressive loss of faunas as conditions deteriorated once the

oceanic link was lost. This is the characteristic signal for

tectonically controlled basins where episodic uplift progres-

sively isolated the basins. As a result of these reduced oceanic

inputs there was an increased climatic constraint of the

Mediterranean hydrology (Blanc-Valleron et al., 2004).

The first signs of restriction become evident, at around

�6.7 Ma. The simultaneous presence of surface-dwellers

(Globigerinoides spp.) indicative of oligotrophic, stratified

waters and deep dwellers as Globorotalia spp. indicative of

mixing water could indicate a strong seasonal contrast. After

�6.4 Ma, rapid and repeated changes in both pelagic and

benthic productivity are indicated by the foraminifera. The low-

diversity benthic faunas are dominated by stress tolerant taxa

(buliminids, bolivinids). Samples barren of planktonic for-

aminifera alternate with samples with a low diversified

planktonic assemblage where T. multiloba, which is tolerant

to increased salinity (e.g. Violanti, 1996; Sierro et al., 2003;

Kouwenhoven et al., 2006) dominates. According to Blanc-

Valleron et al. (2004), these stressful conditions for the marine

microfauna were induced by an increase of the surface water

salinity and a major step in the restriction. These processes may

be linked to the amplification of the glaciation recorded in the

Antarctic, which could have enhanced the effects of the tectonic

closure. Under this situation, water depths are too shallow to

permit access by well-diversified full marine faunas and the

incipient basin is too restricted to permit anything more than

shallow planktonic populations to enter. Conditions across the

basin sill in this scenario are sufficiently shallow to effectively

exclude planktonic foraminifera.

Although constriction of the portals towards the Atlantic

(Betic and Rifan corridors) is by now more or less accepted as a

cause of the MSC, we suspect and find indications for a

superimposed effect of astronomically driven climate cycles.

5. Conclusions

Foraminiferal biostratigraphic and palaeoenvironmental

results from the pre-evaporitic sequence of the Metochia Basin

in the Gavdos Island reveal the detailed history of its

palaeogeographic evolution during the Late Neogene.

Nine biostratigraphic events were recognized based on the

study of planktonic foraminifera. Specifically, the main

calcareous plankton events are the following: (1) LO

Globorotalia nicolae (6.722 Ma); (2) FAO Globigerina obesa

(6.613 Ma); (3) LO Globorotalia conomiozea (6.506 Ma); (4)

FAO Turborotalita multiloba (6.415 Ma); (5) Neogloboqua-

drina acostaensis d/s (6.360 Ma); (6) Globorotalia scitula

influx (6.295 Ma); (7) N. acostaensis dominance sin. Forms

(6.140–6.108 Ma); (8) N. acostaensis influx sin. Forms

(6.082 Ma); (9) N. acostaensis influx sin. Forms (6.015 Ma).

Calcareous plankton assemblages assume an oligotypical

character.

Vertical distribution patterns of palaeoecological useful

benthic foraminifera key groups revealed temporal high

primary productivity periods with dysoxic (bottom water)

conditions due to restricted circulation (stratification). Increas-

ing salinity is inferred by the prominent peak abundances of B.

aculeata and B. spathulata assemblages and of the planktonic

species T. multiloba.

The observed faunal pattern indicates that the pre-evaporitic

succession of the Metochia Basin was deposited under the

influence of tectonics and variable climatically driven

processes.

Acknowledgements

The authors wish to express their gratitude to J. Gaudant and

J.-M. Rouchy for their help during the field work in summer of

2002 and the fruitful discussions on stratigraphy. This study is

part of the Projects no. 70/4/7612 and 70/4/5744 financially

supported by the University of Athens.

References

Abrantes, F., 1988. Diatom assemblages as upwelling indicators in surface

sediments in Portugal. Marine Geology 85, 15–39.

Altenbach, A.V., Sarnthein, M., 1989. Productivity record in benthic Forami-

nifera. In: Berger, W.H., Smetacek, V., Wefer, G. (Eds.), Productivity of the

Ocean: Present and Past. Dahlem-Konferenzen, John Wiley Sons Ltd,

Chichester, pp. 255–269.

Barcena, M.A., Abrantes, F., 1998. Evidence of a high-productivity area off the

coast of Malaga from studies of diatoms in surface sediments. Marine

Micropaleontology 35, 91–103.

Be, A.W.H., 1977. An ecological, zoogeographic and taxonomic review of

recent planktonic foraminifera. In: Ramsey, A.T.S. (Ed.), Oceanic micro-

paleontology. Academic Press, New York, pp. 1–101.

Be, A.W.H., Tolderlund, D.S., 1971. Distribution and ecology of living plank-

tonic Foraminifer in surface waters of the Atlantic and Indian oceans. In:

Funnel, B.M., Riedel, W.R. (Eds.), The Micropaleontology of the Oceans.

Cambridge University Press, London, pp. 105–149.

Bijma, J., Faber Jr., W.W., Hemleben, Ch., 1990. Temperature and salinity

limits for growth and survival of some planktonic foraminifers in laboratory

cultures. Journal of Foraminifera Research 20, 95–116.

Blanc-Valleron, M.-M., Pierre C., Caruso A., Rouchy J.-M., 2004. Paleoenvir-

onmental changes heralding the Messinian salinity crisis in central Sicily: the

Tripoli formation of the Falconara-Gibliscemi composite section. Colloque

Eclipse ‘‘The Messinian Salinity Crisis re-visited’’, Corte, abstract.

Blanc-Valleron, M.-M., Pierre, C., Caulet, J.-P., Caruso, A., Rouchy, J.-M.,

Cespuglio, G., Sprovieri, R., Pestrea, S., Di Stefano, E., 2002. Sedimentary,


stable isotope and micropaleontological records of paleoceanographic

change in the Messinian Tripoli Formation Sicily, Italy. Palaeogeography,

Palaeoclimatology, Palaeoecology 185, 255–286.

Boltovskoy, E., Wright, R. (Eds.), 1976. Recent Foraminifera. Dr. W. Junk b.

v., The Hague.

Caralp, M.H., 1989. Abundance of Bulimina exilis and Melonis barleeanum:

relationship to the quality of marine organic matter. Geo-Marine Letters 19,

37–43.

Cita, M.B., 1975. The Miocene/Pliocene boundary: History and definition. In:

Saito, T., Burckle, L. (Eds.), Late Neogene Epoch Boundaries. Micropa-

leontology. Special Publications 1, pp. 1–30.

Cita, M.B., 1976. Biodynamic effects of the Messinian Salinity Crisis on the

evolution of planktonic foraminifers in the Mediterranean. Palaeogeogra-

phy, Palaeoclimatology, Palaeoecology 20, 23–42.

Cita, M.B., Wright, R.C., Ryan, W.B.F., Longinelli, A., 1978. Messinian

palaeoenvironments. In: Hsu, K.J., Montadert, L. (Eds.), Initial Reports

of the Deep Sea Drilling Project 42. U.S. Government Printing Office,

Washington, pp. 1003–1035.

Coccioni, R., Galeotti, S., 1994. K-T boundary extinction: geologically instan-

taneous or gradual event? Evidence from deep-sea benthic foraminifera.

Geology 22, 779–782.

Corliss, B.H., 1985. Microhabitats of benthic foraminifera within deep-sea

sediments. Nature 314, 435–438.

Corliss, B.H., 1991. Morphology and microhabitat preferences of benthic

foraminifera from the Northwest Atlantic Ocean. Marine Micropaleontol-

ogy 17, 195–236.

Corliss, B.H., Emerson, S., 1990. Distribution of Rose Bengal stained deep-sea

benthic foraminifera from the Nova Scotia continental margin and Gulf of

Maine. Deep-Sea Research 37, 381–400.

de Rijk, S., Jorissen, F.J., Rohling, E.J., Troelstra, S.R., 2000. Organic flux

control on bathymetric zonation of Mediterranean benthic foraminifera.

Marine Micropaleontology 40, 151–166.

Den Dulk, M., Reichart, G.J., Memon, G.M., Roelofs, E.M.P., Zachariasse,

W.J., Van der Zwaan, G.J., 1998. Benthic foraminiferal response to varia-

tions in surface water productivity and oxygenation in the northern Arabian

Sea. Marine Micropaleontology 35, 43–66.

Denne, R.A., Sen Gupta, B.K., 1991. Association of bathyal foraminifera with

water masses in the northwestern Gulf of Mexico. Marine Micropaleontol-

ogy 17, 173–193.

Dermitzakis, M.D., 1978. Stratigraphy and sedimentary history of the Miocene

of Zakynthos (Ionian Islands Greece). Annales Geologique des Pays

Helleniques 29, 47–186.

Erbacher, J., Gerth, W., Schmiedl, G., Hemleben, C., 1998. Benthic forami-

niferal assemblages of late Albian Black Shale intervals form Vocontian

Basin, SE France. Cretaceous Research 19, 805–826.

Erbacher, J., Hemleben, C., Huber, B., Markey, M., 1999. Correlating environ-

mental changes during early Albian oceanic anoxic event 1b using benthic

foraminiferal paleoecology. Marine Micropaleontology 38, 7–28.

Erbacher, J., Huber, B.T., Norris, R.D., Markey, M., 2001. Increased thermoha-

line stratification as a possible cause for an oceanic anoxic event in the

Cretaceous period. Nature 409, 325–327.

Fairbanks, R.G., Sverdlove, M., Free, R., Wiebe, P.H., Be, A.W.H., 1982.

Vertical distribution of living planktonic foraminifera from the Panama

basin. Nature 298, 841–844.

Fairbanks, R.G., Wiebe, P.H., 1980. Foraminifera and Chlorophyll Maximum:

Vertical distribution, seasonal succession and paleoceanographic signifi-

cance. Science 209, 1524–1525.

Fariduddin, F., Loubere, P., 1997. The surface ocean productivity response of

deeper water benthic foraminifera in the Atlantic Ocean. Marine Micro-

paleontology 32, 289–310.

Gage, D., Tyler, P.A. (Eds.), 1991. Deep-Sea Biology: A Natural History of

Organisms at the Deep-Sea Floor. Cambridge University Press, Cambridge.

Gaudant, J., 2002. La crise messinienne et ses effets sur l’ichthyofaune neogene

de la Mediterranee: le temoignage des squelettes en connexion de poissons

teleosteens. Geodiversitas 24, 691–710.

Gaudant, J., Tsaparas, N., Antonarakou, A., Drinia, H., Saint-Martin, S.,

Dermitzakis, M.D., 2006. A new marine fish fauna from the pre-evaporitic

Messinian of Gavdos Island (Greece). Comptes Rendus Palevol 5, 795–802.

Gibson, T.G., 1989. Planktonic/benthonic foraminiferal ratios: modern patterns

and Tertiary applicability. Marine Micropaleontology 15, 29–52.

Gooday, A.J., 1986. Meiofaunal foraminiferans from the bathyal Porcupine

Seabright northeast Atlantic: size structure, standing stock, taxonomic

composition, species diversity and vertical distribution in the sediment.

Deep Sea Research 33, 1345–1373.

Gooday, A.J., 1993. Deep-sea benthic foraminiferal species which exploit

phytodetritus: characteristic features and controls on distribution. Marine


Gupta, A.K., 1997. Paleoceanographic and paleoclimatic history of the Somali

Basin during the Pliocene-Pleistocene: Multivariate analyses of benthic

foraminifera from DSDP site 241 Leg 5. Journal of Foraminiferal Research

27, 196–208.

Hammer, O., Harper, D.A.T., Ryan, P.D., 2001. PAST: paleontological statistics

software package for education and data analysis. Palaeontologia Electro-

nica 4, http://palaeo-electronica.org, /2001_1/past/issue1_01.htm.

Hayward, B.W., Hollis, C.J., Grenfell, H.R., 1997. Recent Elphidiidae (For-

aminiferida) of the south-west Pacific and fossil Elphidiidae of New

Zealand. Institute of Geological and Nuclear Sciences, Monograph 16,

1–166.

Hemleben, C., Spindler, M., Anderson, O.R., 1989. Modern Planktonic For-

aminifera. Springer-Verlag, New York, 1–363.

Hermelin, J.O.R., Shimmield, G.B., 1990. The importance of the Oxygen

Minimum Zone and Sediment Geochemistry in the distribution of Recent

Benthic Foraminifera in the Northwest Indian Ocean. Marine Geology 91,

1–29.

Hilgen, F.J., Krijgsman, W., 1999. Cyclostratigraphy and astrochronology of the

Tripoli diatomite formation pre-evaporite Messinian, Sicily Italy. Terra

Nova 11, 16–22.

Hilgen, F.J., Krijgsman, W., Langereis, C.G., Lourens, L.J., Santarelli, A.,

Zachariasse, W.J., 1995. Extending the astronomical polarity time scale into

the Miocene. Earth and Planetary Science Letters 136, 495–510.

Hilgen, F.J., Krijgsman, W., Raffi, I., Turco, E., Zachariasse, W.J., 2000.

Integrated stratigraphy and astronomical calibration of the Serravallian/

Tortonian boundary Section at Monte Gibliscemi (Sicily, Italy). Marine


Hodell, D.A., Benson, R.H., Kent, D.V., Boersma, A., Rakic-El Bied, K., 1994.

Magnetostratigraphy, biostratigraphy, and stable isotope stratigraphy of a

late Miocene drill core from the Sale Briqueterie Northwestern Morocco: A

high-resolution chronology for the Messinian Stage. Paleoceanography 9,

835–855.

Hodell, D., Curtis, J., Sierro, F.J., Raymo, M., 2001. Correlation of Late

Miocene-to-Early Pliocene Sequences between the Mediterranean and

North Atlantic. Paleoceanography 16, 164–179.

Hsu, K.J., 1972. When the Mediterranean Sea dried up. Scientific American

277, 27–36.

Hsu, K.J., Cita, M.B., Ryan, W.B.F., 1973. The origin of the Mediterranean

evaporites. In: Ryan, W.B.F., Hsu, K.J. (Eds.), Initial Reports of the Deep

Sea Drilling Project 12. U.S. Government Printing Office, Washington, pp.

1203–1231.

Hsu, K.J., Montadert, L., Bernoulli, D., Cita, M.B., Erickson, A., Garrison, R.E.,

Kidd, R.B., Melieres, F., Muller, C., Wright, R.C., 1977. History of the

Mediterranean salinity crisis. Nature 267, 399–403.

Iaccarino, S., 1985. Mediterranean Miocene and Pliocene planktic Foramini-

fera. In: Bolli, H.M., Saunders, J.B., Perch-Nielsen, K. (Eds.), Plankton

Stratigraphy. Cambridge University Press, London, pp. 283–314.

Jannink, N.T., Zachariasse, W.J., Van der Zwaan, G.J., 1998. Living Rose

Bengal Stained benthic foraminifera from the Pakistan continental margin

northern Arabian Sea, Deep-Sea Research. Part 1. Oceanographic Research

Papers 45, 1483–1513.

Jonkers, H.A., 1984. Pliocene benthonic foraminifera from homogeneous and

laminated marls on Crete. Utrecht Micropaleontological Bulletin 31, 1–179.

Jorissen, F.J., 1999. Benthic foraminiferal microhabitats below the sediment-

water interface. In: Sen Gupta, B. (Ed.), Ecology of recent foraminifera.

Kluwer Academic Publishers 10, Dordrecht, pp. 161–179.

Jorissen, F.J., Barmawidjaja, D.M., Puskaric, S., Van der Zwaan, G.J., 1992.

Vertical distribution of benthic foraminifera in the northern Adriatic Sea: the

relation with the organic flux. Marine Micropaleontology 19, 131–146.

http://palaeo-electronica.org/


Jorissen, F.J., Wittling, I., Peypouquet, J.P., Rabouille, C., Relexans, J.C., 1998.

Live benthic foraminiferal faunas off Cape Blanc NW-Africa: Community

structure and microhabitats. Deep-Sea Research 45, 2157–2188.

Kaiho, K., 1994. Benthonic foraminiferal dissolved-oxygen index and dissolved

levels in the modern ocean. Geology 22, 719–722.

Kaiho, K., 1999. Effect of organic carbon flux and dissolved oxygen on the

benthic foraminiferal oxygen index BFOI. Marine Micropaleontology 37,

67–76.

Kawagata, S., 2001. Late Neogene benthic Foraminifera from Kume-jima

Island, central Ryukyu Islands, southwestern Japan. Science Reports of

the Institute of Geoscience, University of Tsukuba. Section B: Geological

Sciences 22, 61–123.

Kennett, J.P., Srinivasan, M.S., 1983. Neogene Planktonic Foraminifera, A

Phylogenetic Atlas. Hutchinson Ross, Stroudsburg, Pennsylvania.

Kouwenhoven, T.J., 2000. Survival under stress: benthic foraminiferal patterns

and Cenozoic biotic crises. Geologica Ultraiectina 186, 1–206.

Kouwenhoven, T.J., Hilgen, F.J., Van der Zwaan, G.J., 2003. Late Tortonian-

early Messinian stepwise disruption of the Mediterranean-Atlantic connec-

tions: constraints from benthic foraminiferal and geochemical data. Palaeo-

geography, Palaeoclimatology, Palaeoecology 198, 303–319.

Kouwnhoven, T.J., Morigi, C., Negri, A., Giunta, S., Krijgsman, W., Rouchy, J.-

M., 2006. Paleoenvironmental evolution of the eastern Mediterranean

during the Messinian: constraints from integrated microfossil data of the

Pissouri Basin (Cyprus). Marine Micropaleontology 60, 17–44.

Kouwenhoven, T.J., Seidenkrantz, M.-S., Van der Zwaan, G.J., Kouwenhoven,

T.J., Seidenkrantz, M.-S., Van der Zwaan, G., 1999. Deep-water changes:

The near-synchronous disappearance of a group of benthic foraminifera

from the late Miocene Mediterranean. Palaeogeography, Palaeoclimatol-

ogy, Palaeoecology 152, 259–281.

Kouwenhoven, T.J., Van der Zwaan, G.J., 2006. A reconstruction of late

Miocene Mediterranean circulation patterns using benthic foraminifera.

Palaeogeography, Palaeoclimatology, Palaeoecology 238, 373–385.

Krijgsman, W., Blanc-Valleron, M.-M., Flecker, R., Hilgen, F.J., Kouwenhoven,

T.J., Merle, D., Orszag-Sperber, F., Rouchy, J.-M., 2002. The onset of the

Messinian salinity crisis in the Eastern Mediterranean Pissouri Basin,Cy-

prus. Earth and Planetary Science Letters 194, 299–310.

Krijgsman, W., Fortuin, A.R., Hilgen, F.J., Sierro, F.J., 2001. Astrochronology

for the Messinian Sorbas basin SE Spain and orbital precessional forcing for

evaporite cyclicity. Sedimentary Geology 140, 43–60.

Krijgsman, W., Hilgen, F.J., Langereis, C.G., Lourens, L.J., Santarelli, A.,

Zachariasse, W.J., 1995. Late Miocene magnetostratigraphy, biostratigra-

phy and cyclostratigraphy from the Mediterranean. Earth Planetary Science

Letters 136, 475–494.

Krijgsman, W., Langereis, C.G., Zachariasse, W.J., Boccaletti, M., Moratti, G.,

Gelati, R., Iaccarino, S., Papani, G., Villa, G., 1999. Late Neogene evolution

of the Taza-Guercif Basin Rifian Corridor, Morocco and implications for the

Messinian salinity crisis. Marine Geology 153, 147–160.

Leckie, R.M., Yuretich, R.F., West, O.L.O., Finkelstein, D., Schmidt, M., 1998.

Paleoceanography of the southwestern Western Interior Sea during the time

of the Cenomanian-Turonian boundary Late Cretaceous. SEPM Concepts in

Sedimentology and Paleontology 6, 101–126.

Linke, P., Lutze, G.F., 1993. Microhabitat preferences of benthic foraminifera -

a static concept or a dynamic adaptation to optimize food acquisition?

Marine Micropaleontology 20, 215–234.

Loubere, P., 1996. The surface ocean productivity and bottom water oxygen

signals in deep water benthic foraminiferal assemblages. Marine Micro-

paleontology 28, 247–261.

Loubere, P., 1997. Benthic foraminiferal assemblage formation, organic carbon

flux and oxygen concentrations on the outer continental shelf and slope.

Journal of Foraminiferal Research 27, 93–100.

Lourens, L.J., Antonarakou, A., Hilgen, F.J., Van Hoof, A.A.M., Vergnaud

Grazzini, C., Zachariasse, W.J., 1996. Evaluation of the Plio-Pleistocene

astronomical timescale. Paleoceanography 11, 391–413.

Lutze, G.F., Coulbourn, W.T., 1984. Recent benthic foraminifera from the

continental margin of northwest Africa: community structure and distribu-

tion. Marine Micropaleontology 8, 361–401.

McKenzie, J.A., Jenkyns, H.C., Bennett, G.G., 1980. Stable isotope study of the

cyclic diatomite-claystones from the Tripoli formation, Sicily: a prelude to

the Messinian salinity crisis. Palaeogeography, Palaeoclimatology, Palaeoe-

cology 29, 125–142.

Merle, D., Pestrea, S., Courme-Rault, M.-D., Zorn, L., Blanc-Valleron, M.-M.,

Orszag-Sperber, F., Krijgsman, W., 2002. Les paleopeuplements marins du

Messinien pre-evaporitique de Pissouri (Chypre Mediterranee orientale):

aspects paleoecologiques precedant la crise de salinite messinienne. Geo-

diversitas 24, 669–689.

Muller, C., 1985. Late Miocene to recent Mediterranean biostratigraphy

and paleoenvironments based on calcareous nannoplankton. In: Stanley,

D.J., Wezel, F.-C. (Eds.), Geological evolution of the Mediterranean Basin.

Springer-Verlag, New York, pp. 471–485.

Muller, D.W., Hsu, K.J., 1987. Event stratigraphy and paleoceanography in the

Fortuna Basin Southeast Spain: a scenario for the Messinian Salinity Crisis.

Paleoceanography 2, 679–696.

Murray, J.W., 1991a. Ecology and Palaeoecology of Benthic Foraminifera.

Longman Harlow, Harlow, 1–397.

Murray, J.W., 1991b. Ecology and distribution of benthic foraminifera. In: Lee,

J.J., Anderson, O.R. (Eds.), Biology of Foraminifera. Academic Press, New

York, pp. 221–254.

Orszag-Sperber, F., Rouchy, J.-M., Bizon, J.J., Cravatte, J., Muller, G., 1980. La

sedimentation messinienne dans le bassin de Polemi (Chypre). Geologie

Mediterraneenne 7, 91–102.

Pedley, H.M., Grasso, M., 1993. Controls on faunal and sediment cyclicity

within the Tripoli and Calcare di Base basins late Miocene of central Sicily.

Palaeogeography, Palaeoclimatology, Palaeoecology 105, 337–360.

Pedley, H.M., Maniscalco, R., 1999. Lithofacies and faunal succession (faunal

phase analysis) as a tool in unraveling climatic and tectonic signals in

marginal basins; Messinian (Miocene), Sicily. Journal of the Geological

Society of London 156, 855–863.

Perez-Folgado, M., Sierro, F.J., Barcena, M.A., Flores, J.A., Vazquez, A.,

Utrilla, R., Hilgen, F.J., Krijgsman, W., Filipelli, G.M., 2003. Western

versus eastern Mediterranean paleoceanographic response to astronomical

forcing: a high-resolution microplankton study of precession-controlled

sedimentary cycles during the Messinian. Palaeogeography, Palaeoclima-

tology, Palaeoecology 190, 317–334.

Phleger, F.B., Parker, F.L., Peirson, J.F., 1953. North Atlantic foraminifera.

In: Pettersson, H. (Ed.), Reports of the Swedish Deep-Sea Expedition

1947-1948, Sediment cores from the North Atlantic, 7 (1). Sweden, pp.

3–122.

Phleger, F.B., Soutar, A., 1973. Production of benthic foraminifera in three east

Pacific oxygen minima. Micropaleontology 19, 110–115.

Prell, W.L., 1984. Variation of monsoonal upwelling: a response to changing

solar radiation. In: Hansen, J.E., Takahashi, T. (Eds.), Climate processes

and climate sensitivity. M. Ewing, Vol.5. Geophysical Monograph 29,

American Geophysical Union, Washington, pp. 48–57.

Reynolds, L., Thunell, R.C., 1985. Seasonal succession of planktonic forami-

nifera in the subpolar North Pacific. Journal of Foraminifera Research 15,

282–301.

Robertson, B.E., 1998. Systematics and paleoecology of the benthic Forami-

niferida from the Buff Bay section. Miocene of Jamaica. Micropaleontology

44, 1–266.

Robertson, A.H.F., Eaton, S.E., Follows, E.J., Payne, A.S., 1995. Sedimentol-

ogy and depositional processes of Miocene evaporites from Cyprus. Terra

Nova 7, 233–254.

Rodrıguez, L., Escribano, R., 1996. Bahıa Antofagasta y Bahıa de Mejillones

del Sur: Observaciones de la temperatura, penetracion de la luz, biomasa y

composicion fitoplanctonica. Estudios Oceanologicos 15, 75–85.

Rouchy, J.-M., 1982. La genese des evaporites messiniennes de Mediterranee.

Memoires du Museum National d’Histoire Naturelle 50, 1–267.

Rouchy, J.-M., 1986. Les evaporites miocenes de la Mediterranee et de la mer

Rouge et leurs enseignements pour l’interpretation des grandes accumula-

tions evaporitiques d’origine marine. Bulletin de la Societe geologique de

France 8, 511–520.

Rouchy, J.-M., Caruso, A., 2006. The Messinian salinity crisis in the Medi-

terranean basin: a re-appraisal of the data and an integrated scenario. In:

Rouchy, J.-M., Suc, J.-P., Ferrandini, J., Ferrandini, M. (Eds.), The

Messinian Salinity Crisis Revisited. Sedimentary Geology, 188/189. pp.

35–68.


Rouchy, J.-M., Taberner, C., Blanc-Valleron, M.-M., Sprovieri, R., Russell, M.,

Pierre, C., Di Stefano, E., Pueyo, J.J., Caruso, A., Dinares-Turell, J., Gomis-

Coll, E., Wolff, G.A., Cespuglio, G., Ditchfield, P., Pestrea, S., Combourieu-

Nebout, N., Santisteban, C., Grimalt, J.O., 1998. Sedimentary and diage-

netic markers of the restriction in a marine basin: the Lorca Basin SE Spain

during the Messinian. Sedimentary Geology 121, 23–55.

Ryan, W.B.F., Hsu, K.J., et, al. (Eds.), 1973. Initial Reports of the Deep Sea

Drilling Project 13 (1, 2).U.S. Government Printing Office, Washington,

1–1447.

Samir, A.M., 2000. The response of benthic foraminifera and ostracods to

various pollution sources: A study from two lagoons in Egypt. Journal of

Foraminiferal Research 30, 83–98.

Schafer, C.T., Collins, E.S., Smith, J.N., 1991. Relationship of Foraminifera and

thecamoebian distributions to sediments contaminated by pulp mill effluent:

Saguenay Fiord, Quebec, Canada. Marine Micropaleontology 17, 255–283.

Schmiedl, G., Mitschele, A., Beck, S., Emeis, K.C., Hemleben, C., Schulz, H.,

Sperling, M., Weldeab, S., 2003. Benthic foraminiferal record of ecosystem

variability in the eastern Mediterranean Sea during times of sapropel S5 and

S6 deposition. Palaeogeography, Palaeoclimatology, Palaeoecology 190,

139–164.

Seidenkrantz, M.-S., Kouwenhoven, T.J., Jorissen, F.J., Shackleton, N.J., Van

der Zwaan, G.J., 2000. Benthic foraminifera as indicators of changing

Mediterranean-Atlantic water exchange in the late Miocene. Marine Geol-

ogy 163, 387–407.

Selli, R., 1960. Il Messiniano Mayer-Eymar 1867, Proposta di un neostratotipo.

Giornale di Geologia 28, 1–34.

Sen Gupta, B.K., Lee, R.F., May III, M.S., 1989. Upwelling and unusual

assemblage of benthic foraminifera on the northern Florida continental

slope. Journal of Paleontology 55, 853–857.

Sen Gupta, B.K., Machain-Castillo, M.L., 1993. Benthic foraminifera in

oxygen-poor habitats. Marine Micropaleontology 20, 183–201.

Sen Gupta, B.K., Temples, T.J., Dallmeyer, M.D.G., 1981. Stratigraphic trends

of late Quaternary benthic foraminifera in the eastern Caribbean Sea:

Abstracts with Programs. Geological Society of America 13, p. 551.

Sierro, F.J., Flores, J.A., Barcena, M.A., Vasquez, A., Utrilla, R., Zamarreno, I.,

2003. Orbitally-controlled oscillations in the planktonic communities and

cyclical changes in western Mediterranean hydrography during the Messi-

nian. Palaeogeography, Palaeoclimatology, Palaeoecology 190, 289–316.

Sierro, F.J., Flores, J.A., Zamarreno, I., Vasquez, A., Utrilla, R., Frances, G.,

Hilgen, F.J., Krijgsman, W., 1999. Messinian pre-evaporite sapropels and

precession-induced oscillation in western Mediterranean climate. Marine

Geology 153, 137–146.

Sierro, F.J., Hilgen, F.J., Krijgsman, W., Flores, J.A., 2001. The Abad composite

SE Spain: A Messinian reference section for the Mediterranean and the

APTS. Palaeogeography, Palaeoclimatology, Palaeoecology 168, 141–169.

Sonnenfeld, P., 1974. A Mediterranean catastrophe? Geological Magazine 111,

79–86.

Sprovieri, R., Di Stefano, E., Caruso, A., Bonomo, S., 1996. High resolution

stratigraphy in the Messinian Tripoli Formation in Sicily. Paleopelagos 6,

415–435.

Sprovieri, R., Hasegawa, S., 1990. Plio-Pleistocene Benthic foraminifer

stratigraphic distribution in the deep-sea record of the Tyrrhenian sea

(ODP LEG 107), Proceedings of the Ocean Drilling Program, Scientific

Results 107, 429-459.

Suc, J.-P., Violanti, D., Londeix, L., Poumot, C., Robert, C., Clauzon, G.,

Gautier, F., Turon, J.-L., Ferrier, J., Chikhi, H., Cambon, G., 1995. Evolution

of the Messinian Mediterranean environments: the Tripoli Formation at

Capodarso Sicily,Italy. Review of Palaeobotany and Palynology 87, 51–79.

Thiede, J., 1983. Skeletal plankton and nekton in upwelling water masses off

northwestern South America and northwest Africa. In: Suess, E., Thiede, J.

(Eds.), Coastal Upwelling. Plenum. New York, pp. 183–207.

Thomas, E., 1980. The development of Uvigerina in the Cretan Mio-Pliocene.

Utrecht Micropaleontological Bulletin 23, 1–168.

Tolderlund, D.S., Be, A.W.H., 1971. Seasonal distribution of planktonic for-

aminifera in the western North Atlantic. Micropaleontology 17, 297–329.

Triantaphyllou, M.V., Tsaparas, N., Stamatakis, M., Dermitzakis, M.D., 1999.

Calcareous nannofossil biostratigraphy and petrological analysis of the pre-

evaporitic diatomaceous sediments from Gavdos Island, southern Greece.

Neues Jahrbuch fur Geologie und Palaontologie Monatshefte 161–178.

Van de Poel, H.M., 1992. Foraminiferal biostratigraphy and paleoenvironments

of the Miocene-Pliocene Carboneras-Nijar Basin (SE Spain). Scripta Geo-

logica 102, 1–32.

Van der Zwaan, G.J., 1979. The pre-evaporite Late Miocene environment of the

Mediterranean; stable isotopes of planktonic foraminifera from section

Falconara Sicily. Koninklijke Nederlandse Akademie Van Wetenschappen

82, 487–502.

Van der Zwaan, G.J., 1982. Paleoecology of Late Miocene foraminifera. Utrecht

Micropaleontological Bulletin 25, 1–201.

Van der Zwaan, G.J., 1983. Quantitative analyses and the reconstruction of

benthic foraminiferal communities. Utrecht Micropaleontological Bulletin

30, 49–69.

Van der Zwaan, G.J., Duijnstee, I.A.P., den Dulk, M., Ernst, S.R., Jannink, N.T.,

Kouwenhoven, T.J., 1999. Benthic foraminifers: proxies or problems? A

review of paleoecological concepts. Earth-Science Reviews 46, 213–236.

Van der Zwaan, G.J., den Hartog Jager, D., 1983. Paleoecology of Late Miocene

Sicilian benthic foraminifera. Proceedings of the Koninklijke Nederlandse

Akademie Van Wetenschappen, Ser. B, 86, 211–223.

Van der Zwaan, G.J., Jorissen, F.J., de Stigter, H.C., 1990. The depth depen-

dency of planktonic/benthic foraminiferal ratios: constraints and applica-

tions. Marine Geology 95, 1–16.

Vergnaud Grazzini, C., Ryan, W.B.F., Cita, M.B., 1977. Stable isotope fractio-

nation, climate change and episodic stagnation in the eastern Mediterranean

Sea. Sedimentary Geology 28, 81–93.

Verhallen, P.J.J.M., 1991. Late Pliocene to Early Pleistocene Mediterranean

mud-dwelling foraminifera; influence of a changing environment of com-

munity structure and evolution. Utrecht Micropaleontological Bulletin 40,

1–219.

Violanti, D., 1996. Paleoautecological analysis of Bulimina echinata (Messi-

nian Mediterranean area). In: Cherchi, A. (Ed.), Autoecology of Selected

Fossil Organisms. Bolletino della Societa Paleontologica Italiana, 3. pp.

243–253.

Zobel, B., 1973. Biostratigraphische Untersuchungen an Sedimenten des

indisch-pakistanischen Kontinentalrandes Arabisches Meer. Meteor For-

schungsergebnisse C12, 9–73.

Documents

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