the geological record of a mid-holocene marine storm in southwestern spain
TRANSCRIPT
Original article
The geological record of a mid-Holocene marine storm
in southwestern Spain
´ ˆ `
http://france.elsevier.com/direct/GEOBIO
Geobios 40 (2007) 689–699
L’enregistrement geologique d’une tempete marine holocene
du Sud-Ouest de l’Espagne
Francisco Ruiz a,*, Jose Borrego b, Nieves Lopez-Gonzalez b, Manuel Abad a,Maria Luz Gonzalez-Regalado a, Berta Carro b, Jose Gabriel Pendon b,
Joaquın Rodrıguez-Vidal a, Luis Miguel Caceres a, Maria Isabel Prudencio c,Maria Isabel Dias c
a Departamento de Geodinamica y Paleontologıa, Facultad de Ciencias Experimentales, Universidad de Huelva, Avda. Fuerzas Armadas s/n, 21071 Huelva, Spainb Departamento de Geologıa, Facultad de Ciencias Experimentales, Universidad de Huelva, Avda. Fuerzas Armadas s/n, 21071 Huelva, Spain
c Instituto Tecnologico e Nuclear, EN 10, 2686-953 Sacavem, Portugal
Received 19 May 2006; accepted 4 December 2006
Available online 8 August 2007
Abstract
Integrated analysis of a 50-m long sedimentary core collected in the central part of the Odiel estuary (SW Atlantic coast of Spain) allows
delineation of the main paleoenvironmental changes that occurred in this area during the Holocene. Eight sedimentary facies were deposited in the
last ca. 9000 years BP, confirming a transgressive–regressive cycle that involves the transition from fluvial to salt marsh deposits with intermediate
marine tidal deposits. A storm event is detected at ca. 5705 14C years BP (mean calibrated age) with distinct lithostratigraphical, textural,
geochemical, and palaeontological features.
# 2007 Elsevier Masson SAS. All rights reserved.
Resume
L’analyse geologique d’un forage obtenu dans la partie centrale de l’estuaire du fleuve Odiel (Sud-Ouest de l’Espagne) a permis la definition des
principaux evenements paleoenvironnementaux holocene dans ce secteur. Huit facies sedimentaires ont ete differencies sur un substrat neogene. Ils
constituent un cycle transgressif–regressif incluant des depots marins entre graviers fluviatiles a la base et des sediments fins de marais. Un
evenement de haute energie (tempete) a ete enregistre vers ca. 5705 14C years BP au sommet, dont les caracteristiques lithostratigraphiques,
geochimiques et paleontologiques sont distinctives.
# 2007 Elsevier Masson SAS. All rights reserved.
Keywords: Estuarine facies; Storm; Holocene; SW Spain
Mots cles : Facies ; Estuaires ; Tempete ; Holocene ; SO Espagne
1. Introduction
In the last decade, numerous investigations have focused on
the geological deposits derived from the action of past storms,
tsunamis, and other high-energy events. Most of these studies
* Corresponding author.
E-mail address: [email protected] (F. Ruiz).
0016-6995/$ – see front matter # 2007 Elsevier Masson SAS. All rights reserved
doi:10.1016/j.geobios.2006.12.003
are based on textural analyses of sediments through vertical
sections and sometimes include geochemical data (Chague-
Goff et al., 2002) and microfaunal studies based on ostracods
(Hindson and Andrade, 1999), planktonic and benthic
foraminifera (McMurty et al., 2004; Abrantes et al., 2005;
Williams et al., 2006), dinoflagellates (Allen, 2003), or pollen
(Kontopoulos and Avraimidis, 2003). Generally, a single event
was detected (Dawson and Smith, 2000; Banerjee et al., 2001;
.
F. Ruiz et al. / Geobios 40 (2007) 689–699690
Altunel et al., 2004), although as many as six tsunamis have
been recorded in a few cores (i.e., Kontopoulos and Avraimidis,
2003; Nomade et al., 2005). Storm or tsunami periodicity has
been tracked in very recent time series (from 1950 or later),
with the application of both spectral and Monte Carlo analysis
(Levin and Sasorova, 2002; Watts, 2004).
In coastal environments, sedimentary deposits associated
with tsunamis are characterized by: (a) large boulders, boulder
ridges, pebbles, and shells high above the modern storm level
(Scheffers and Kelletat, 2005); (b) washover fans (Luque et al.,
2002); (c) sandy, sometimes bioclastic sheets with evidences of
bidirectional flows (Nanayama et al., 2000); (d) sandy layers
intercalated in muddy deposits (Fujiwara et al., 2000); or (e)
shell-bearing deposits sandwiched by fossil soils (McMurty
et al., 2004). Usually, they have an erosional base and consist of
coarser sediments relative to the overlying and underlying layers
(Takashimizu and Masuda, 2000). In contrast, important erosion
may be detected in the adjacent shallow-marine environments
(Abrantes et al., 2005). Sedimentological and geomorphological
imprints of these high-energy deposits are reviewed in Dawson
and Shi (2000) and Scheffers and Kelletat (2003).
In these areas, the geological record of storm events is
constituted by: (a) sandy layers with basal erosional surfaces
interlayered in muddy sediments (Myrow and Southard, 1996;
Budillon et al., 2005); (b) new beach ridges added periodically to
sandy spits (Rodrıguez-Ramırez et al., 2003); or (c) lumachellic
layers of mollusc shells interbedded within massive, bioturbated
levels (Gonzalez Delgado et al., 1995). Differences between the
geological record of storm or tsunamis are reviewed in Davies
and Haslett (2000). Tsunami deposits are generally thinner than
those of storms, they can extend hundreds of meters inland,
create a new macrotopography and usually comprise a single bed
that is normally graded overall (Goff, 2006).
On the southwestern Spanish coast, 18 tsunamis have been
documented since 218 BC (Campos, 1992), with the generation
of washover fans (Luque et al., 2001, 2002) or bioclastic sandy
sheets (Lario, 1996; Ruiz et al., 2004). Other tsunamigenic
layers have been found at ca. 5300 14C years BP, ca. 4182–415214C years BP and 3862–3763 14C years BP (Ruiz et al., 2005).
In this area, the tectonic source of earthquakes and the
associated tsunamis are located along the Azores fault,
generated by the dynamics of the Iberia–Africa plate margin
(Zitellini et al., 1999, 2004). In addition, this zone is exposed to
frequent winter storms, with a remarkable periodicity (3–6
years in most cases; Rodrıguez-Ramırez et al., 2003).
The aim of this paper is the geological characterization of
the different sedimentary bodies that constitute the infilling of
the Odiel River estuary (SW Spain). Lithological, geochemical,
and palaeontological data are the basis for the recognition of
Holocene palaeoenvironmental changes, with special attention
to the identification of high-energy events like storm or
tsunamigenic deposits.
2. The Odiel estuary
The Odiel River estuary is a bar-built system (cf. Fairbridge,
1980) located on the southwestern Spanish coast. This coastal
environment is well-known for high levels of heavy metals
(Ruiz, 2001; Borrego et al., 2002, 2004) derived from: (1) the
large amounts of suspended and dissolved trace elements
coming from the acid drainage of the Iberian Pyrite Belt, the
biggest sulphide ore in Europe and (2) the presence of two
industrial complexes in the estuarine central basin, including
chemical factories, petroleum refineries, and a paper mill.
The inner part of this coastal environment is composed of
wide tidal flats and salt marshes separated by ebb-tide channels.
The mouth is composed of three geographical elements (Fig. 1),
separated by three channels: (1) the Punta Umbria spit, to the
west, (2) the Saltes Island, which comprises a complex system
of sandy ridges, subparallel to the coastline, and (3) the Torre
Arenillas spit, developed on the eastern margin and directly
linked with a Plio-Pleistocene cliff.
The Iberian Pyrite Belt constitutes the main geological
substratum of the Odiel River drainage network. Near the
mouth, the Holocene estuarine sediments were deposited on
Miocene–Pliocene siliciclastic sediments deposited in marine/
continental environments (Civis et al., 1987). This Tertiary
succession is composed of basal grey-blue clays and marls
(Gibraleon Clays Formation) and upper fine sands and grey-
yellow marls (Huelva Formation). These formations constitute
a large system of cliffs distributed along the coastline that
surrounds the estuary.
3. Materials and methods
A continuous core (50 m long) was obtained from Bacuta
Island, located near the main channel of the Odiel River
(Fig. 1). Initial analysis delineated the main lithostratigraphic
units using particle size analysis of 35 subsamples (20 g) and
the estimation of the clay-silt contents in a ZM model
COULTER particle counter. Geochemical analyses of addi-
tional subsamples were performed on the bulk samples by X-
ray Assay Laboratories, Toronto (Canada). Metal concentra-
tions were determined by X-ray Fluorescence (SiO2, Al2O3,
CaO, MgO, Na2O, K2O, Fe2O3, MnO, TiO2, P2O5) and ICP
Spectrometry (Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Y, Zr,
Mo, Ag, Ba, La, Pb, Bi). Calibration is based on over 40
international standard reference materials.
The palaeontological record was obtained from 50 g
subsamples washed through a 63 mm sieve to remove the
mud fraction and then dried. Bivalves and gastropods were
identified to the species level, whereas the total ostracod fauna
was picked and 300 foraminifers were counted (if possible),
with a subsequent extrapolation to the whole sample.
Two dates were produced at the Geochron Laboratories by
radiocarbon analysis of mollusc shells. Data were calibrated
using CALIB version 4.2 (Stuiver and Reimer, 1993) and the
Stuiver et al. (1998) calibration dataset. The final results
correspond to calibrated ages (ca.) using 2s intervals with a
reservoir correction (�440 � 85 years) as suggested by Lario
(1996) and Dabrio et al. (1998, 2000) for this area. Ages
discussed below are expressed as the highest probable age of
the 2s calibrated range (e.g., van der Kaars et al., 2001).
Fig. 1. (A) Geographical setting of the Tinto–Odiel estuary with location of the Bacuta core. (B) Facies and spelling samples along the core.
Fig. 1. (A) Geologie de l’estuaire des fleuves Tinto et Odiel, avec la localisation du forage Bacuta. (B) Facies sedimentaires et echantillons etudies.
F. Ruiz et al. / Geobios 40 (2007) 689–699 691
4. Description of the core
The sedimentological analysis identifies eight lithological
units (Fig. 2). Below 38 m depth the core comprises massive,
grey-blue clayey silts with scarce fragmentary bivalves (Facies
1). Foraminifers are abundant, with numerous benthic species
(Florilus boueanum, Marginulina costata, Ammonia spp.,
Sphaeroidina bulloides) and high percentages (30–50%) of
planktonic specimens (Orbulina universa, Globigerina spp.,
Globigerinoides spp., Globorotalia spp.). Ostracods are
represented by scarce Henryhowella asperrima, Krithe spp.,
Parakrithe spp. and Cytherella vulgata.
Fig. 2. Textural analysis of the samples collected.
Fig. 2. Analyse texturale des echantillons.
F. Ruiz et al. / Geobios 40 (2007) 689–699692
An erosional contact separates this basal facies from the
overlying Facies 2, which is 5 m thickness and is made up of
gravels and very coarse to medium sands with a matrix of
brownish to yellowish silty clays. This quartz-rich facies shows
the lowest values of CaO, K2O (Table 1), and some trace
elements (Ag, Ba, Be, Sr) (Table 2).
The overlying 11.3 m comprises green clayey silts (Facies 3)
with high percentages (50–70%) of fine to medium-grained
silts. The basal samples show high percentages of Al2O3, MgO,
K2O, MnO, and TiO2, decreasing toward the top (Table 1).
Some bivalves (Acanthocardia aculeata, Corbula gibba) and
gastropods (Hinia reticulata) are frequent near the base of this
unit, whereas these groups are rare in the upper samples.
Benthic foraminifers are rare (1–3 individuals/gram) with
Ammonia inflata and Quinqueloculina seminulum as the
dominant species. The former is abundant in the basal samples
and decreases toward the top, whereas the latter is more
frequent in the upper part of this facies. Near the base, ostracods
are represented by Palmoconcha laevata, an opportunistic
species very abundant in the earliest estuarine Holocene
deposits of this area (Ruiz et al., 2005). This species is replaced
progressively by Carinocythereis whitei and Urocythereis
oblonga, two marine species (Ruiz et al., 1997), in the upper
samples.
Facies 4 comprises 12.2 m of very fine to medium-grained
yellow sands (60–85% sand) with scattered fragments of
marine molluscs (mainly Chamelea gallina and H. reticu-
lata). This facies presents the highest SiO2 percentage of
the core and the lowest percentage of the remaining major
elements and trace metals analyzed. Foraminifers are scarce
(5 individuals/gram) in the basal sample, being represented
mainly by marine species (Ammonia beccarii, F. boueanum,
Q. seminulum) and minor contributions of A. inflata.
A. beccarii and Q. seminulum characterize the remaining
samples, although very rare individuals were found in the
central part (samples 12–15: 7–20 specimens/50 gram) of this
facies. Scarce individuals of the marine ostracod U. oblonga
were found in the basal sample, whereas these microcrus-
taceans are rare in samples 12–17. The two upper samples
show a diverse assemblage (22 species) dominated by the
marine species U. oblonga and Pontocythere elongata, and
include 20–35% of estuarine species (Loxoconcha spp.,
Leptocythere spp.).
This sandy layer is overlain by a thin sheet of bioclastic
sands (Facies 5), with an abrupt contact between these two
facies. This layer is characterized by remarkable decrease of the
SiO2 percentages and an important increase in normalized
concentrations of Fe, Ti (Fig. 3) and some metals (Ni, Y, V, and
Cr), which coincide with very high CaO contents (10.2%), and
low amounts of mud (14.4%). This conjunction can be
explained by the presence of high, heavy metal concentrations
(mainly titanium-bearing minerals) and bioclastic remains.
This facies has the highest diversity of marine bivalves and
gastropods (Fig. 4) of the whole core, most of them partially
abraded, together with fragments of both scaphopods and
anthozoans.
Facies 6 comprises very bioturbated silty sands with high
proportions (50%) of very fine sands, increasing clay content
toward the top and scattered fragments of both bivalves
(mainly Ostreidae) and gastropods. These sediments show
intermediate values in both major elements and trace metals
between Facies 4 and Facies 7. Foraminifers are very abundant
in sample SB-8 (17 species; �2750 individuals/gram), with a
predominance of estuarine (75%; A. inflata, Astrononion
stelligerum, Cribroelphidium vadescens, Haynesina germa-
nica) over marine species (Planobulina mediterranensis, Q.
seminulum). Ostracods are frequent (30 species; 7 individuals/
gram), being marine forms still dominant over the estuarine
assemblages (Fig. 5).
The next 2 m (Facies 7) are formed of gray to black clayey
silts with important percentages of fine and very fine silts (40–
55%) and secondary clays (10–15%). The base of this unit is
Table 1
Concentrations of major elements in the different sedimentary facies. Black cells: highest values; black numbers: lowest values. Grey row: high-energy layer
Tableau 1
Concentrations des elements majeurs dans les differents facies sedimentaires. Cellules noires : valeurs maximales ; nombres noirs : valeurs minimales. Gris :
evenement de haute energie
F. Ruiz et al. / Geobios 40 (2007) 689–699 693
strongly bioturbated, with numerous burrows filled by very fine
sands and reworked fragments of bivalves. The geochemical
features are similar to those observed in the basal samples of
Facies 3. The scarce microfauna (1–2 individuals/gram) is
Table 2
Concentrations of trace metals in the Bacuta core. Black cells: highest values; bla
Tableau 2
Concentrations des elements traces dans le forage de Bacuta. Cellules noires : vale
energie
composed almost exclusively by estuarine foraminifers (A.
inflata, A. stelligerum) and ostracods (Loxococoncha rhomboi-
dea, Cytherois fischeri), whereas no specimen of either group
was found in the upper sample.
ck numbers: lowest values. Grey row: high-energy layer
urs maximales ; nombres noirs : valeurs minimales. Gris : evenement de haute
Fig. 3. Al-normalized diagrams of Ti, Fe, Ni, Cr and V.
Fig. 3. Diagrammes normalises (avec Al) de Ti, Fe, Ni, Cr et V.
F. Ruiz et al. / Geobios 40 (2007) 689–699694
Fig. 4. Distribution of molluscs in the core.
Fig. 4. Distribution des mollusques dans le forage.
F. Ruiz et al. / Geobios 40 (2007) 689–699 695
Fig. 5. Distribution of foraminifers and ostracods in the core, with definition of the main Holocene environmental changes in the central part of the Odiel estuary.
Fig. 5. Distribution des foraminiferes et ostracodes le long du forage et definition des principaux changements environnementaux holocenes dans la partie centrale du
fleuve Odiel.
F. Ruiz et al. / Geobios 40 (2007) 689–699696
Finally, Facies 8 is made up of red clayey silts strongly
bioturbated by roots with fine to very fine silts (52–65%),
dominant over clays (14–20%). The upper sample presents very
high contents of Fe2O3 and heavy metals (Table 2), as
consequence of the millennial mining and recent industrial
contamination. The very rare microfauna consist of the
foraminifer Jadammina macrescens.
The last 2 m of the core consist of artificial fill derived from
the dredging of the Padre Santo Channel and the waste of
several saltworks located in Bacuta Island.
F. Ruiz et al. / Geobios 40 (2007) 689–699 697
5. Discussion
5.1. Palaeoenvironmental reconstruction
This multivariate analysis permits to reconstruct the
palaeoenvironmental changes that happened in the Odiel River
estuary during the Holocene. Sedimentological and palaeonto-
logical features of Facies 1 are very similar to those observed in
the Gibraleon Clay Formation (Tortonian–Zanclian), one of the
most representative Neogene Formations of southwestern
Spain (Civis et al., 1987). These deposits were deposited in
upper bathyal to circalittoral environments, according to the
microfaunal content (Ruiz and Gonzalez-Regalado, 1996;
Gonzalez-Regalado and Ruiz, 1996).
The overlying deposits (Facies 2), which eroded these
Neogene sediments, have a coarse grain size and are devoid of
fossils. They have a fluvial origin and are similar to those
observed in pre-estuarine, fluvial sediments collected in diverse
cores obtained in this estuary, with ages of ca. 25,000–30,00014C years BP (Dabrio et al., 2000).
The microfaunal contents of Facies 3 are dominated by the
foraminifers A. inflata and Q. seminulum. A. inflata is the most
representative and widespread species in the southwestern
Spanish estuaries and appears to be generalist, with a
distribution little sensitive to the grain size distributions or
the salinity ranges. Q. seminulum is well distributed in the
outer, seaward areas of the estuaries, especially in the channel
margin and the subtidal environments located near the mouth
(Gonzalez-Regalado et al., 2001). Consequently, Facies 3
constitutes the first Holocene estuarine deposits (sample 28: ca.
9060 14C years BP) and represents basal accretionary estuarine
bodies, with an increasing marine influence toward the top.
Basal and intermediate samples of Facies 4 show a marine
faunal content (Figs. 4 and 5), with the presence of infralittoral
ostracods (U. oblonga, P. elongata), foraminifers (A. beccarii,
Elphidium crispum), bivalves (Anomia ephippium, C. gallina),
and gastropods (H. reticulata) (Perez Quintero, 1989; Ruiz
et al., 1997; Gonzalez-Regalado et al., 2001). These sediments
are coarser than Facies 3 and are indicative of an increasing
energy, which may explain the absence or the presence of very
few individuals of foraminifers and ostracods (Ruiz et al.,
2000). These samples were deposited approximately during the
Flandrian transgressive maximum in this area (ca. 6500 14C
years BP; Zazo et al., 1994). In contrast, the upper samples
represent the beginning of a regression period, with a
significant increase of estuarine faunal assemblages (Fig. 5:
A. inflata, C. vadescens, H. germanica, Loxoconcha elliptica,
C. fischeri).
Facies 5 represents an interruption in the regressive
sequence, with increasing percentages of shallow marine
foraminifers (A. beccarii, Q. seminulum) and ostracods
(U. oblonga, P. elongata, C. whitei). This marine precedence
is confirmed by the important percentages of ilmenite and other
heavy minerals, very abundant in the shallow marine sediments
adjacent to the Tinto–Odiel estuary (Fernandez Caliani et al.,
1997). These features, together with the presence of frequent
fragments of molluscs, may be indicative of a high-energy
event that transported marine sediments toward the central part
of the Odiel River estuary. The associated radiocarbon dating
(ca. 5705 years BP) indicated that this sample could be the
evidence of the oldest Holocene high-energy event dated in this
coast at present (see review in Ruiz et al., 2005).
Numerous species present in Facies 6 (A. inflata,
A. stelligerum, H. germanica) are found in very shallow
distributary channels (1–2 m depth) in modern southwestern
Spanish estuaries, with high salinity variations (Ruiz et al.,
2000; Gonzalez-Regalado et al., 2001). These data indicate a
gradual transition from subtidal to intertidal environments and
an increasing restriction of the tidal fluxes owing to progressive
estuarine sediment fill. This transition continues in sample SB-
7, where the estuarine assemblages of both foraminifers and
ostracods are clearly dominant (75–100%). There is an abrupt
diminution of the abundance in both groups, owing to the
increasing subaerial exposure (Carbonel, 1980).
Finally, similar sedimentary deposits to Facies 7 were found
in the channel border of some distributary channels located in
the Guadiana and Tinto–Odiel estuaries (Morales, 1993;
Borrego et al., 1995), whereas the foraminiferal content of
Facies 8 is common in high salt marshes of Europe and America
(Pujos, 1984; Scott and Leckie, 1990; Gonzalez-Regalado
et al., 2001). These facies represent the transition from
intertidal to supratidal conditions.
Consequently, this vertical sequence represents a basal
transgressive system tract followed by a regression that
represents a high stand system tract. A similar evolution has
been indicated by Dabrio et al. (1998, 2000) in the analysis of
numerous cores collected in different estuaries of southwestern
Spain. This general evolution is only interrupted by a high-
energy event (Facies 5).
5.2. Facies 5: storm or tsunami?
A comparison with different tsunamigenic deposits of
southwestern Spain and other coastal areas permits to
delimitate the origin of Facies 5.
� G
rain size. Mean grain size of Facies 5 is very similar toFacies 4 (Fig. 4), with low differences derived from the higher
percentages of bioclasts (7% dry weight). Tsunamigenic
deposits show generally distinctive, coarser sediments in
relation to the underlying layers (Ruiz et al., 2005), whereas
some storm beds may exhibit similar textural features to those
deposited under fair weather conditions (Gonzalez Delgado
et al., 1995).
� M
acrofauna. Facies 5 present fragments of marine bivalvesand small gastropods, although its percentages are very low in
relation to other tsunamigenic layers (30–50% dry weight).
Mean size of these bioclasts is lower than 5 mm, whereas
tsunamigenic, bioclastic shells content larger individuals
(diameter up to 5 cm) of Cardium, Ostrea or Glycymeris
(Ruiz et al., 2004).
� M
icrofauna. Both marine ostracods and foraminifers increasein Facies 5 in relation to the upper samples of Facies 4,
although the distributions of these groups are similar to those
F. Ruiz et al. / Geobios 40 (2007) 689–699698
observed in some intermediate samples of this latter facies. In
southern Portugal, microfaunal contents of tsunamigenic
deposits contrast markedly with the underlying facies
(Hindson et al., 1998). These evidences indicate a storm
origin for Facies 5, with the introduction of small marine
bioclasts and heavy metals.
6. Conclusions
The integration of lithological, stratigraphical, geochemical,
and palaeontological data allow the definition of eight
sedimentary facies in the Holocene infilling of the Odiel estuary.
The Holocene depositional sequence starts with the sedimenta-
tion of fluvial, azoic gravels, and coarse sands over a Neogene
substrate. Between ca. 9060 14C years BP and ca. 6500 14C years
BP, this estuary was flooded progressively, with a transgressive
cycle composed of basal estuarine deposits and upper high-
energy tidal deposits. Since ca. 6500 14C years BP, a regressive
period is detected by the transition from marine to salt marsh
environments, including the geological record of the oldest
known Holocene storm in this area (ca. 5705 14C years BP).
Acknowledgements
This work was funded by two Spanish DGYCIT Projects
(CTM2006-06722/MAR and CGL2006-01412/BTE), and three
Research Groups of the Andalusia Board (RNM-183, RNM-
238, and RNM-276). This paper is a contribution to the IGCP
396, 437, and 495.
References
Abrantes, F., Lebreiro, S., Rodrigues, T., Gil, I., Bartels-Jonsdottir, H., Oliveira,
P., Kissel, C., Grimalt, J.O., 2005. Shallow-marine sediment cores record
climate variability and earthquake activity off Lisbon (Portugal) for the last
2000 years. Quaternary Science Reviews 24, 2477–2494.
Allen, H.D., 2003. A transient coastal wetland: from estuarine to supratidal
conditions in less than 2000 years-Boca do Rio, Algarve, Portugal. Land
Degradation and Development 14, 265–283.
Altunel, E., Meghraoui, M., Akyuz, H.S., Dikbas, A., 2004. Characteristics of the
1912 co-seismic rupture along the North Anatolian Fault Zone (Turkey):
implications for the expected Marmara earthquake. Terra Nova 16, 198–204.
Banerjee, D., Murray, A.S., Foster, I.D.L., 2001. Scilly Isles, UK: optical dating
of a possible tsunami deposit from the 1755 Lisbon earthquake. Quaternary
Science Reviews 20, 715–718.
Borrego, J., Lopez-Gonzalez, N., Carro, B., 2004. Geochemical signature as
paleoenvironmental marker in Holocene sediments of the Tinto river
estuary (southwestern Spain). Estuarine, Coastal and Shelf Science 61,
631–641.
Borrego, J., Morales, J.A., Pendon, J.G., 1995. Holocene estuarine facies
along the mesotidal coast of Huelva, southwestern Spain. In: Flemming,
B.W., Bartholoma, A. (Eds.), Tidal Signatures in Modern and Ancient
Sediments, vol. 24. International Association of Sedimentologists (Spe-
cial Publication), pp. 151–170.
Borrego, J., Morales, J.A., De La Torre, M.L., Grande, J.A., 2002. Geochemical
characteristic of heavy metal pollution in surface sediments of the Tinto and
Odiel river estuary (southwestern Spain). Environmental Geology 41, 785–
796.
Budillon, F., Esposito, E., Lorio, M., Pelosi, N., Porfido, S., Violante, C., 2005.
The geological record of store events over the last 1000 years in the Salerno
Bay (Southern Tyrrhenian Sea): new proxy evidences. Advances in Geos-
ciences 2, 123–130.
Campos, M.L., 1992. El riesgo de Tsunamis en Espana. Analisis y valoracion
geografica. IGN, Monografıas 9, 1–204.
Carbonel, P., 1980. Les ostracodes et leur interet dans la definition des
ecosystemes estuariens et de la plateforme continentale. Essais d’applica-
tion a des domaines anciens. Memoires de l’Institut de Geologie du Bassin
d’Aquitaine 11, 1–350.
Chague-Goff, C., Dawson, S., Goff, J.R., Zachariasen, J., Berryman, K.R.,
Garnett, D.L., Waldron, H.M., Mildenhall, D.C., 2002. A tsunami (ca. 6300
years BP) and other Holocene changes, northern Hawke’s Bay, New
Zealand. Sedimentary Geology 150, 89–102.
Civis, J., Sierro, F.J., Gonzalez-Delgado, J.A., Flores, J.A., Andres, I., Porta,
J., Valle, M.F., 1987. El Neogeno marino de la Provincia de Huelva:
Antecedentes y definicion de las unidades litoestratigraficas. In: Civis, J.
(Ed.), Paleontologıa del Neogeno de Huelva (W Cuenca del Guadalqui-
vir). Universidad de Salamanca, pp. 9–20.
Dabrio, C.J., Zazo, C., Goy, J.L., Sierro, F., Borja, F., Lario, J., Gonzalez, J.A.,
Flores, J.A., 2000. Depositional history of estuarine infill during the last
postglacial transgression (Gulf of Cadiz, Southern Spain). Marine Geology
162, 381–404.
Dabrio, C.J., Zazo, C., Lario, J., Goy, J.L., Sierro, F.J., Borja, F., Gonzalez, J.A.,
Flores, J.A., 1998. Sequence stratigraphy of Holocene incised valley fills
and coastal evolution in the Gulf of Cadiz (southern Spain). Geologie in
Mijnbouw-Netherlands Journal of Geosciences 77, 23–281.
Davies, P., Haslett, S.K., 2000. Identifying storm or tsunami events in coastal
basin sediments. Area 32, 335–336.
Dawson, A.G., Shi, S.Z., 2000. Tsunami deposits. Pure and Applied Geophysics
157, 875–897.
Dawson, S., Smith, D.E., 2000. The sedimentology of Middle Holocene
tsunami facies in northern Sutherland, Scotland, UK. Marine Geology
170, 69–79.
Fairbridge, R., 1980. The estuary: its definition and geodynamic cycle. In:
Olausson, E., Cato, I. (Eds.), Chemistry and Biogeochemistry of Estuaries.
John Wiley and Sons, Chichester, pp. 1–35.
Fernandez Caliani, J.C., Ruiz, F., Galan, E., 1997. Clay mineral and heavy metal
distributions in the lower estuary of Huelva and adjacent Atlantic shelf, SW
Spain. Science of Total Environment 198, 181–200.
Fujiwara, O., Masuda, F., Sakai Irizuki, T., Fuse, K., 2000. Tsunami deposits in
Holocene bay mud in southern Kanto region, Pacific coast of central Japan.
Sedimentary Geology 135, 219–230.
Goff, J.R., 2006. When is a tsunami not a tsunami? When is it a storm?. In: Gulf
Coast Association of Geological Societies, 56th Conference. Lafayette,
Louisana, September 25–27 (Abstracts).
Gonzalez Delgado, J.A., Andres, I., Sierro, F.J., 1995. Late Neogene molluscan
faunas from the Northeast Atlantic (Portugal, Spain, Morocco). Geobios 28,
459–471.
Gonzalez-Regalado, M.L., Ruiz, F., 1996. Les foraminiferes benthiques de la
baie du sud-ouest de l’Espagne pendant le Neogene superieur : le Mio-
Pliocene de Huelva. Revue de Paleobiologie 15, 109–120.
Gonzalez-Regalado, M.L., Ruiz, F., Baceta, J.I., Gonzalez-Regalado, E.,
Munoz, J.M., 2001. Total benthic foraminifera assemblages in the south-
western Spanish estuaries. Geobios 34, 39–51.
Hindson, R.A., Andrade, C., 1999. Sedimentation and hydrodynamic processes
associated with the tsunami generated by the 1755 Lisbon earthquake.
Quaternary International 56, 27–38.
Hindson, R.A., Andrade, C., Parish, R., 1998. A microfaunal and sedimentary
record of environmental change within the Late Holocene sediments of
Boca do Rio (Algarve, Portugal). Geologie in Mijnbouw-Netherlands
Journal of Geosciences 77, 311–321.
Kontopoulos, N., Avraimidis, P., 2003. A late Holocene record of environmental
changes from the Aliki lagoon, Egion, North Peloponnesus, Greece. Qua-
ternary International 111, 75–90.
Lario, J., 1996. Ultimo y Presente Interglacial en el area de conexion Atlantico-
Mediterraneo: variaciones del nivel del mar, paleoclima y paleoambientes.
Ph.D. Thesis. Universidad Complutense de Madrid.
Levin, B.W., Sasorova, E.V., 2002. On the 6-year tsunami periodicity in the
Pacific. Izvestiya, Physics of the Solid Earth 38, 1030–1038.
F. Ruiz et al. / Geobios 40 (2007) 689–699 699
Luque, L., Lario, J., Civis, J., Silva, P.G., Zazo, C., Goy, J.L., Dabrio, C.J., 2002.
Sedimentary record of a tsunami during Roman times, Bay of Cadiz, Spain.
Journal of Quaternary Science 17, 623–631.
Luque, L., Lario, L., Zazo, C., Goy, J.L., Dabrio, C.J., Silva, P.G., 2001.
Tsunami deposits as paleoseismic indicators: examples from the Spanish
coast. Acta Geologica Hispanica 36, 197–211.
McMurty, G.M., Watts, P., Fryer, G.J., Smith, J.R., Imamura, F., 2004. Giant
landslides, megatsunamis, and paleo-sea level in the Hawaiian Islands.
Marine Geology 203, 219–233.
Morales, J.A., 1993. Sedimentologıa del estuario del rıo Guadiana (S.O. de
Espana y Portugal). Ph.D. Thesis. Universidad de Huelva.
Myrow, P., Southard, J.B., 1996. Tempestite deposition. Journal of Sedimentary
Geology 66, 875–887.
Nanayama, F., Shigeno, K., Satake, K., Shimokawa, K., Koitabashi, S.,
Miyasaka, S., Ishii, M., 2000. Sedimentary differences between the
1993 Hokkaido-nansei-oki tsunami and the 1959 Miyakojima typhoon
at Taipei, southwestern Hokkaido, northern Japan. Sedimentary Geology
135, 255–264.
Nomade, J., Chapron, E., Desmet, M., Reyss, J.L., Arnaud, F., Lignier, V., 2005.
Reconstructing historical seismicity from lake sediments (Lake Laffrey,
Western Alps, France). Terra Nova 17, 350–357.
Perez Quintero, J.C., 1989. Introduccion a los Moluscos onubenses I: Faunıs-
tica. Junta de Andalucıa A.M.A.
Pujos, M., 1984. Jadammina macrescens, temoin d’un environnement contra-
ignant dans l’estuaire de la Gironde (France). In: Oertli, H. (Ed.), Benthos’
83, Proceedings of the 2nd International Symposium on Benthic Forami-
nifera, Pau and Bordeaux, pp. 511–517.
Rodrıguez-Ramırez, A., Ruiz, F., Caceres, L.M., Rodrıguez-Vidal, J., Pino, R.,
Munoz, J.M., 2003. Analysis of the recent storm record in the southwestern
Spanish coast: implications for littoral management. The Science of the
Total Environment 303, 189–201.
Ruiz, F., 2001. Trace metals in estuarine sediments of southwestern Spain.
Marine Pollution Bulletin 42, 482–490.
Ruiz, F., Gonzalez-Regalado, M.L., 1996. Les ostracodes du Golfe Mio-
Pliocene du sud-ouest de l’Espagne. Revue de Micropaleontologie 39,
137–151.
Ruiz, F., Gonzalez-Regalado, M.L., Baceta, J.I., Munoz, J.M., 2000. Compara-
tive ecological analysis of the ostracod faunas from low- and high-polluted
southwestern Spanish estuaries: a multivariate approach. Marine Micro-
paleontology 40, 345–376.
Ruiz, F., Gonzalez-Regalado, M.L., Morales, J.A., 1997. Ecologıa de ostraco-
dos en medios estuarinos: el Subsistema Carreras (rio Guadiana, SO de
Espana). Estudios Geologicos 53, 249–262.
Ruiz, F., Rodrıguez-Ramırez, A., Caceres, L.M., Rodrıguez Vidal, J., Carretero,
M.I., Abad, M., Olıas, M., Pozo, M., 2005. Evidences of high-energy events
in the geological record: Middle Holocene evolution of the southwestern
Donana National Park. Palaeogeography, Palaeoclimatology, Palaeoecol-
ogy 229, 212–229.
Ruiz, F., Rodriguez-Ramirez, A., Caceres, L.M., Rodriguez-Vidal, J., Carretero,
M.I., Clemente, L., Munoz, J.M., Yanez, C., Abad, M., 2004. Late Holocene
evolution of the southwestern Donana National Park (Guadalquivir Estuary,
SW Spain): a multivariate approach. Palaeogeography, Palaeoclimatology,
Palaeoecology 204, 47–64.
Scheffers, A., Kelletat, D., 2003. Sedimentologic and geomorphologic tsunami
imprints world-wide. A review. Earth Science Reviews 63, 83–92.
Scheffers, A., Kelletat, D., 2005. Tsunami relics on the coastal landscape west
of Lisbon, Portugal. Science Tsunami Hazards 23, 3–16.
Scott, D.B., Leckie, E.M., 1990. Foraminiferal zonation of Great Sippewissett
salt marsh (Falmouth, Massachusetts). Journal of Foraminiferal Research
20, 248–266.
Stuiver, M., Reimer, P.J., 1993. Radiocarbon calibration program. Rev. 4.2.
Radiocarbon 35, 215–230.
Stuiver, M., Reimer, P.J., Bard, E., Beck, J.W., Burr, G.S., Hughen, K.A.,
Kromer, B., McCormac, G., van der Plicht, J., Spurk, M., 1998. INTCAL98
Radiocarbon age calibration 24, 000-0 ca BP. Radiocarbon 40, 1041–1083.
Takashimizu, Y., Masuda, F., 2000. Depositional facies and sedimentary
successions of earthquake-induced tsunami deposits in Upper Pleistocene
incised valley fills, central Japan. Sedimentary Geology 135, 231–239.
van der Kaars, S., Penny, D., Tibby, J., Fluin, J., Dam, R.A.C., Suparan, P., 2001.
Late Quaternary palaeoecology, palynology and palaeolimnology of a
tropical lowland swamp: Rawa Danau, West-Java, Indonesia. Palaeogeo-
graphy, Palaeoclimatology, Palaeoecology 171, 185–212.
Watts, P., 2004. Probabilistic predictions of landslide tsunamis off Southern
California. Marine Geology 203, 281–301.
Williams, M., Wilkinson, I.P., Tappin, D.R., McMurtry, G., Fryer, G.J., 2006.
The Hawaiian megatsunami of 110 � 10 Ka: the use of microfossils in
detection. Journal of Micropaleontology 25, 55–56.
Zazo, C., Goy, J.L., Somoza, L., Dabrio, C.J., Brilvomini, G., Impronta, S.,
Lario, J., Bardaji, T., Silva, P.G., 1994. Holocene sequence of sea-level
fluctuations in relation to climatic trends in the Atlantic-Mediterranean
linkage coast. Journal of Coastal Research 10, 933–945.
Zitellini, N., Chierici, F., Sartori, R., Torelli, L., 1999. The tectonic source of the
1755 Lisbon Earthquake. Annali di Geofisica 42, 49–55.
Zitellini, N., Rovere, M., Terrinha, P., Matias, L., Bigsets, T., 2004. Neogene
through Quaternary tectonic reactivation of SW Iberian passive margin.
Pure and Applied Geophysics 161, 565–587.