The Geological Record of a Mid-Holocene Marine Storm In

Geobios 40 (2007) 689–699 http://france.elsevier.com/direct/GEOBIO Original article The geological record of a mid-Holocene marine storm in southwestern Spain L’enregistrement geólogique d’une tempeˆte marine holoce`ne du Sud-Ouest de l’Espagne Francisco Ruiz a,*, Jose´ Borrego b, Nieves Lo´pez-Gonza´lez b, Manuel Abad a, Maria Luz Gonza´lez-Regalado a, Berta Carro b, Jose´ Gabriel Pendoń b, Joaquıń Rodrı´guez-Vidal a, Luis Miguel Caćeres a, Maria Isabel Prudeˆncio c, Maria Isabel Dias c a Departamento de Geodina´mica y Paleontologıá, Facultad de Ciencias Experimentales, Universidad de Huelva, Avda. Fuerzas Armadas s/n, 21071 Huelva, Spain b Departamento de Geologıá, Facultad de Ciencias Experimentales, Universidad de Huelva, Avda. Fuerzas Armadas s/n, 21071 Huelva, Spain c Instituto Tecnolo´gico e Nuclear, EN 10, 2686-953 Sacave´m, 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.

Re´sume´ L’analyse geólogique d’un forage obtenu dans la partie centrale de l’estuaire du fleuve Odiel (Sud-Ouest de l’Espagne) a permis la de´finition des principaux e´veńements paleóenvironnementaux holoce`ne dans ce secteur. Huit facies se´dimentaires ont e´te´ diffe´rencie´s sur un substrat neóge`ne. Ils constituent un cycle transgressif–re´gressif incluant des de´poˆts marins entre graviers fluviatiles a` la base et des se´diments fins de marais. Un e´veńement de haute eńergie (tempeˆte) a e´te´ enregistre´ vers ca. 5705 14C years BP au sommet, dont les caracte´ristiques lithostratigraphiques, geóchimiques et paleóntologiques sont distinctives. # 2007 Elsevier Masson SAS. All rights reserved.

Keywords: Estuarine facies; Storm; Holocene; SW Spain

Mots cle´s: Facies ; Estuaires ; Tempeˆte ; Holoce`ne ; SO Espagne

1. Introduction are based on textural analyses of sediments through vertical sections and sometimes include geochemical data (Chague- In the last decade, numerous investigations have focused on Goff et al., 2002) and microfaunal studies based on ostracods the geological deposits derived from the action of past storms, (Hindson and Andrade, 1999), planktonic and benthic tsunamis, and other high-energy events. Most of these studies foraminifera (McMurty et al., 2004; Abrantes et al., 2005; Williams et al., 2006), dinoﬂagellates (Allen, 2003), or pollen * Corresponding author. (Kontopoulos and Avraimidis, 2003). Generally, a single event E-mail address: [email protected] (F. Ruiz). was detected (Dawson and Smith, 2000; Banerjee et al., 2001;

Altunel et al., 2004), although as many as six tsunamis have environment is well-known for high levels of heavy metals been recorded in a few cores (i.e., Kontopoulos and Avraimidis, (Ruiz, 2001; Borrego et al., 2002, 2004) derived from: (1) the 2003; Nomade et al., 2005). Storm or tsunami periodicity has large amounts of suspended and dissolved trace elements been tracked in very recent time series (from 1950 or later), coming from the acid drainage of the Iberian Pyrite Belt, the with the application of both spectral and Monte Carlo analysis biggest sulphide ore in Europe and (2) the presence of two (Levin and Sasorova, 2002; Watts, 2004). industrial complexes in the estuarine central basin, including In coastal environments, sedimentary deposits associated chemical factories, petroleum refineries, and a paper mill. with tsunamis are characterized by: (a) large boulders, boulder The inner part of this coastal environment is composed of ridges, pebbles, and shells high above the modern storm level wide tidal flats and salt marshes separated by ebb-tide channels. (Scheffers and Kelletat, 2005); (b) washover fans (Luque et al., The mouth is composed of three geographical elements (Fig. 1), 2002); (c) sandy, sometimes bioclastic sheets with evidences of separated by three channels: (1) the Punta Umbria spit, to the bidirectional flows (Nanayama et al., 2000); (d) sandy layers west, (2) the Saltes Island, which comprises a complex system intercalated in muddy deposits (Fujiwara et al., 2000); or (e) of sandy ridges, subparallel to the coastline, and (3) the Torre shell-bearing deposits sandwiched by fossil soils (McMurty Arenillas spit, developed on the eastern margin and directly et al., 2004). Usually, they have an erosional base and consist of linked with a Plio-Pleistocene cliff. coarser sediments relative to the overlying and underlying layers The Iberian Pyrite Belt constitutes the main geological (Takashimizu and Masuda, 2000). In contrast, important erosion substratum of the Odiel River drainage network. Near the may be detected in the adjacent shallow-marine environments mouth, the Holocene estuarine sediments were deposited on (Abrantes et al., 2005). Sedimentological and geomorphological Miocene–Pliocene siliciclastic sediments deposited in marine/ imprints of these high-energy deposits are reviewed in Dawson continental environments (Civis et al., 1987). This Tertiary and Shi (2000) and Scheffers and Kelletat (2003). succession is composed of basal grey-blue clays and marls In these areas, the geological record of storm events is (Gibraleon Clays Formation) and upper fine sands and grey- constituted by: (a) sandy layers with basal erosional surfaces yellow marls (Huelva Formation). These formations constitute interlayered in muddy sediments (Myrow and Southard, 1996; a large system of cliffs distributed along the coastline that Budillon et al., 2005); (b) new beach ridges added periodically to surrounds the estuary. sandy spits (Rodrı´guez-Ramı´rez et al., 2003); or (c) lumachellic layers of mollusc shells interbedded within massive, bioturbated levels (Gonza´lez Delgado et al., 1995). Differences between the 3. Materials and methods geological record of storm or tsunamis are reviewed in Davies and Haslett (2000). Tsunami deposits are generally thinner than A continuous core (50 m long) was obtained from Bacuta those of storms, they can extend hundreds of meters inland, Island, located near the main channel of the Odiel River create a new macrotopography and usually comprise a single bed (Fig. 1). Initial analysis delineated the main lithostratigraphic that is normally graded overall (Goff, 2006). units using particle size analysis of 35 subsamples (20 g) and On the southwestern Spanish coast, 18 tsunamis have been the estimation of the clay-silt contents in a ZM model documented since 218 BC (Campos, 1992), with the generation COULTER particle counter. Geochemical analyses of addi- of washover fans (Luque et al., 2001, 2002) or bioclastic sandy tional subsamples were performed on the bulk samples by X- sheets (Lario, 1996; Ruiz et al., 2004). Other tsunamigenic ray Assay Laboratories, Toronto (Canada). Metal concentra- 14 layers have been found at ca. 5300 C years BP, ca. 4182–4152 tions were determined by X-ray Fluorescence (SiO2,Al2O3, 14 14 C years BP and 3862–3763 C years BP (Ruiz et al., 2005). CaO, MgO, Na2O, K2O, Fe2O3, MnO, TiO2,P2O5) and ICP In this area, the tectonic source of earthquakes and the Spectrometry (Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Y, Zr, associated tsunamis are located along the Azores fault, Mo, Ag, Ba, La, Pb, Bi). Calibration is based on over 40 generated by the dynamics of the Iberia–Africa plate margin international standard reference materials. (Zitellini et al., 1999, 2004). In addition, this zone is exposed to The palaeontological record was obtained from 50 g frequent winter storms, with a remarkable periodicity (3–6 subsamples washed through a 63 mm sieve to remove the years in most cases; Rodrı´guez-Ramı´rez et al., 2003). mud fraction and then dried. Bivalves and gastropods were The aim of this paper is the geological characterization of identified to the species level, whereas the total ostracod fauna the different sedimentary bodies that constitute the infilling of was picked and 300 foraminifers were counted (if possible), the Odiel River estuary (SW Spain). Lithological, geochemical, with a subsequent extrapolation to the whole sample. and palaeontological data are the basis for the recognition of Two dates were produced at the Geochron Laboratories by Holocene palaeoenvironmental changes, with special attention radiocarbon analysis of mollusc shells. Data were calibrated to the identification of high-energy events like storm or using CALIB version 4.2 (Stuiver and Reimer, 1993) and the tsunamigenic deposits. Stuiver et al. (1998) calibration dataset. The final results correspond to calibrated ages (ca.) using 2s intervals with a 2. The Odiel estuary reservoir correction (À440 Æ 85 years) as suggested by Lario (1996) and Dabrio et al. (1998, 2000) for this area. Ages The Odiel River estuary is a bar-built system (cf. Fairbridge, discussed below are expressed as the highest probable age of 1980) located on the southwestern Spanish coast. This coastal the 2s calibrated range (e.g., van der Kaars et al., 2001). F. Ruiz et al. / Geobios 40 (2007) 689–699 691

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)Geólogie de l’estuaire des fleuves Tinto et Odiel, avec la localisation du forage Bacuta. (B) Facie`sse´dimentaires et ećhantillons e´tudie´s.

4. Description of the core (Florilus boueanum, Marginulina costata, Ammonia spp., Sphaeroidina bulloides) and high percentages (30–50%) of The sedimentological analysis identiﬁes eight lithological planktonic specimens (Orbulina universa, Globigerina spp., units (Fig. 2). Below 38 m depth the core comprises massive, Globigerinoides spp., Globorotalia spp.). Ostracods are grey-blue clayey silts with scarce fragmentary bivalves (Facies represented by scarce Henryhowella asperrima, Krithe spp., 1). Foraminifers are abundant, with numerous benthic species Parakrithe spp. and Cytherella vulgata. 692 F. Ruiz et al. / Geobios 40 (2007) 689–699

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. reticulata). 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 Fig. 2. Textural analysis of the samples collected. gastropods (Fig. 4) of the whole core, most of them partially Fig. 2. Analyse texturale des ećhantillons. abraded, together with fragments of both scaphopods and anthozoans. Facies 6 comprises very bioturbated silty sands with high An erosional contact separates this basal facies from the proportions (50%) of very fine sands, increasing clay content overlying Facies 2, which is 5 m thickness and is made up of toward the top and scattered fragments of both bivalves gravels and very coarse to medium sands with a matrix of (mainly Ostreidae) and gastropods. These sediments show brownish to yellowish silty clays. This quartz-rich facies shows intermediate values in both major elements and trace metals the lowest values of CaO, K2O(Table 1), and some trace between Facies 4 and Facies 7. Foraminifers are very abundant elements (Ag, Ba, Be, Sr) (Table 2). in sample SB-8 (17 species; 2750 individuals/gram), with a The overlying 11.3 m comprises green clayey silts (Facies 3) predominance of estuarine (75%; A. inflata, Astrononion with high percentages (50–70%) of fine to medium-grained stelligerum, Cribroelphidium vadescens, Haynesina germa- silts. The basal samples show high percentages of Al2O3, MgO, nica) over marine species (Planobulina mediterranensis, Q. K2O, MnO, and TiO2, decreasing toward the top (Table 1). seminulum). Ostracods are frequent (30 species; 7 individuals/ Some bivalves (Acanthocardia aculeata, Corbula gibba) and gram), being marine forms still dominant over the estuarine gastropods (Hinia reticulata) are frequent near the base of this assemblages (Fig. 5). unit, whereas these groups are rare in the upper samples. The next 2 m (Facies 7) are formed of gray to black clayey Benthic foraminifers are rare (1–3 individuals/gram) with silts with important percentages of fine and very fine silts (40– Ammonia inflata and Quinqueloculina seminulum as the 55%) and secondary clays (10–15%). The base of this unit is F. Ruiz et al. / Geobios 40 (2007) 689–699 693

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 e´le´ments majeurs dans les diffe´rents facie`sse´dimentaires. Cellules noires : valeurs maximales ; nombres noirs : valeurs minimales. Gris : e´ve´nement de haute e´nergie

strongly bioturbated, with numerous burrows filled by very fine composed almost exclusively by estuarine foraminifers (A. sands and reworked fragments of bivalves. The geochemical inflata, A. stelligerum) and ostracods (Loxococoncha rhomboi- features are similar to those observed in the basal samples of dea, Cytherois fischeri), whereas no specimen of either group Facies 3. The scarce microfauna (1–2 individuals/gram) is was found in the upper sample.

Table 2 Concentrations of trace metals in the Bacuta core. Black cells: highest values; black numbers: lowest values. Grey row: high-energy layer Tableau 2 Concentrations des e´le´ments traces dans le forage de Bacuta. Cellules noires : valeurs maximales ; nombres noirs : valeurs minimales. Gris : e´ve´nement de haute e´nergie 694 F. Ruiz et al. / Geobios 40 (2007) 689–699

Fig. 3. Al-normalized diagrams of Ti, Fe, Ni, Cr and V. Fig. 3. Diagrammes normalise´s (avec Al) de Ti, Fe, Ni, Cr et V. F. Ruiz et al. / Geobios 40 (2007) 689–699 695

Fig. 4. Distribution of molluscs in the core. Fig. 4. Distribution des mollusques dans le forage. 696 F. Ruiz et al. / Geobios 40 (2007) 689–699

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 foraminife`res et ostracodes le long du forage et de´finition des principaux changements environnementaux holoce`nes dans la partie centrale du fleuve Odiel.

Finally, Facies 8 is made up of red clayey silts strongly contamination. The very rare microfauna consist of the bioturbated by roots with fine to very fine silts (52–65%), foraminifer Jadammina macrescens. dominant over clays (14–20%). The upper sample presents very The last 2 m of the core consist of artificial fill derived from high contents of Fe2O3 and heavy metals (Table 2), as the dredging of the Padre Santo Channel and the waste of consequence of the millennial mining and recent industrial several saltworks located in Bacuta Island. F. Ruiz et al. / Geobios 40 (2007) 689–699 697

5. Discussion event that transported marine sediments toward the central part of the Odiel River estuary. The associated radiocarbon dating 5.1. Palaeoenvironmental reconstruction (ca. 5705 years BP) indicated that this sample could be the evidence of the oldest Holocene high-energy event dated in this This multivariate analysis permits to reconstruct the coast at present (see review in Ruiz et al., 2005). palaeoenvironmental changes that happened in the Odiel River Numerous species present in Facies 6 (A. inflata, estuary during the Holocene. Sedimentological and palaeonto- A. stelligerum, H. germanica) are found in very shallow logical features of Facies 1 are very similar to those observed in distributary channels (1–2 m depth) in modern southwestern the Gibraleon Clay Formation (Tortonian–Zanclian), one of the Spanish estuaries, with high salinity variations (Ruiz et al., most representative Neogene Formations of southwestern 2000; Gonza´lez-Regalado et al., 2001). These data indicate a Spain (Civis et al., 1987). These deposits were deposited in gradual transition from subtidal to intertidal environments and upper bathyal to circalittoral environments, according to the an increasing restriction of the tidal fluxes owing to progressive microfaunal content (Ruiz and Gonza´lez-Regalado, 1996; estuarine sediment fill. This transition continues in sample SB- Gonza´lez-Regalado and Ruiz, 1996). 7, where the estuarine assemblages of both foraminifers and The overlying deposits (Facies 2), which eroded these ostracods are clearly dominant (75–100%). There is an abrupt Neogene sediments, have a coarse grain size and are devoid of diminution of the abundance in both groups, owing to the fossils. They have a fluvial origin and are similar to those increasing subaerial exposure (Carbonel, 1980). observed in pre-estuarine, fluvial sediments collected in diverse Finally, similar sedimentary deposits to Facies 7 were found cores obtained in this estuary, with ages of ca. 25,000–30,000 in the channel border of some distributary channels located in 14C years BP (Dabrio et al., 2000). the Guadiana and Tinto–Odiel estuaries (Morales, 1993; The microfaunal contents of Facies 3 are dominated by the Borrego et al., 1995), whereas the foraminiferal content of foraminifers A. inflata and Q. seminulum. A. inflata is the most Facies 8 is common in high salt marshes of Europe and America representative and widespread species in the southwestern (Pujos, 1984; Scott and Leckie, 1990; Gonza´lez-Regalado Spanish estuaries and appears to be generalist, with a et al., 2001). These facies represent the transition from distribution little sensitive to the grain size distributions or intertidal to supratidal conditions. the salinity ranges. Q. seminulum is well distributed in the Consequently, this vertical sequence represents a basal outer, seaward areas of the estuaries, especially in the channel transgressive system tract followed by a regression that margin and the subtidal environments located near the mouth represents a high stand system tract. A similar evolution has (Gonza´lez-Regalado et al., 2001). Consequently, Facies 3 been indicated by Dabrio et al. (1998, 2000) in the analysis of constitutes the first Holocene estuarine deposits (sample 28: ca. numerous cores collected in different estuaries of southwestern 9060 14C years BP) and represents basal accretionary estuarine Spain. This general evolution is only interrupted by a high- bodies, with an increasing marine influence toward the top. energy event (Facies 5). Basal and intermediate samples of Facies 4 show a marine faunal content (Figs. 4 and 5), with the presence of infralittoral 5.2. Facies 5: storm or tsunami? ostracods (U. oblonga, P. elongata), foraminifers (A. beccarii, Elphidium crispum), bivalves (Anomia ephippium, C. gallina), A comparison with different tsunamigenic deposits of and gastropods (H. reticulata)(Pe´rez Quintero, 1989; Ruiz southwestern Spain and other coastal areas permits to et al., 1997; Gonza´lez-Regalado et al., 2001). These sediments delimitate the origin of Facies 5. are coarser than Facies 3 and are indicative of an increasing energy, which may explain the absence or the presence of very Grain size. Mean grain size of Facies 5 is very similar to few individuals of foraminifers and ostracods (Ruiz et al., Facies 4 (Fig. 4), with low differences derived from the higher 2000). These samples were deposited approximately during the percentages of bioclasts (7% dry weight). Tsunamigenic Flandrian transgressive maximum in this area (ca. 6500 14C deposits show generally distinctive, coarser sediments in years BP; Zazo et al., 1994). In contrast, the upper samples relation to the underlying layers (Ruiz et al., 2005), whereas represent the beginning of a regression period, with a some storm beds may exhibit similar textural features to those significant increase of estuarine faunal assemblages (Fig. 5: deposited under fair weather conditions (Gonza´lez Delgado A. inflata, C. vadescens, H. germanica, Loxoconcha elliptica, et al., 1995). C. fischeri). Macrofauna. Facies 5 present fragments of marine bivalves Facies 5 represents an interruption in the regressive and small gastropods, although its percentages are very low in sequence, with increasing percentages of shallow marine relation to other tsunamigenic layers (30–50% dry weight). foraminifers (A. beccarii, Q. seminulum) and ostracods Mean size of these bioclasts is lower than 5 mm, whereas (U. oblonga, P. elongata, C. whitei). This marine precedence tsunamigenic, bioclastic shells content larger individuals is confirmed by the important percentages of ilmenite and other (diameter up to 5 cm) of Cardium, Ostrea or Glycymeris heavy minerals, very abundant in the shallow marine sediments (Ruiz et al., 2004). adjacent to the Tinto–Odiel estuary (Fernańdez Caliani et al., Microfauna. Both marine ostracods and foraminifers increase 1997). These features, together with the presence of frequent in Facies 5 in relation to the upper samples of Facies 4, fragments of molluscs, may be indicative of a high-energy although the distributions of these groups are similar to those 698 F. Ruiz et al. / Geobios 40 (2007) 689–699

observed in some intermediate samples of this latter facies. In Bay (Southern Tyrrhenian Sea): new proxy evidences. Advances in Geos- southern Portugal, microfaunal contents of tsunamigenic ciences 2, 123–130. Campos, M.L., 1992. El riesgo de Tsunamis en Espanã. Ana´lisis y valoracioń deposits contrast markedly with the underlying facies geogra´fica. IGN, Monografıás 9, 1–204. (Hindson et al., 1998). These evidences indicate a storm Carbonel, P., 1980. Les ostracodes et leur inte´reˆt dans la de´finition des origin for Facies 5, with the introduction of small marine ećosyste`mes estuariens et de la plateforme continentale. Essais d’applica- bioclasts and heavy metals. tion a` des domaines anciens. Me´moires de l’Institut de Geólogie 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 6. Conclusions years BP) and other Holocene changes, northern Hawke’s Bay, New Zealand. Sedimentary Geology 150, 89–102. The integration of lithological, stratigraphical, geochemical, Civis, J., Sierro, F.J., Gonza´lez-Delgado, J.A., Flores, J.A., Andre´s, I., Porta, and palaeontological data allow the definition of eight J.,Valle,M.F.,1987.ElNeo´geno marino de la Provincia de Huelva: sedimentary facies in the Holocene infilling of the Odiel estuary. Antecedentes y definicioń de las unidades litoestratigra´ficas. In: Civis, J. (Ed.), PaleontologıádelNeo´geno de Huelva (W Cuenca del Guadalqui- The Holocene depositional sequence starts with the sedimenta- vir). Universidad de Salamanca, pp. 9–20. tion of fluvial, azoic gravels, and coarse sands over a Neogene Dabrio, C.J., Zazo, C., Goy, J.L., Sierro, F., Borja, F., Lario, J., Gonza´lez, J.A., 14 14 substrate. Between ca. 9060 C years BP and ca. 6500 C years Flores, J.A., 2000. Depositional history of estuarine infill during the last BP, this estuary was flooded progressively, with a transgressive postglacial transgression (Gulf of Cadiz, Southern Spain). Marine Geology cycle composed of basal estuarine deposits and upper high- 162, 381–404. 14 Dabrio, C.J., Zazo, C., Lario, J., Goy, J.L., Sierro, F.J., Borja, F., Gonza´lez, J.A., energy tidal deposits. Since ca. 6500 C years BP, a regressive Flores, J.A., 1998. Sequence stratigraphy of Holocene incised valley fills period is detected by the transition from marine to salt marsh and coastal evolution in the Gulf of Ca´diz (southern Spain). Geologie in environments, including the geological record of the oldest Mijnbouw-Netherlands Journal of Geosciences 77, 23–281. known Holocene storm in this area (ca. 5705 14C years BP). 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 Acknowledgements 157, 875–897. Dawson, S., Smith, D.E., 2000. The sedimentology of Middle Holocene This work was funded by two Spanish DGYCIT Projects tsunami facies in northern Sutherland, Scotland, UK. Marine Geology (CTM2006-06722/MAR and CGL2006-01412/BTE), and three 170, 69–79. Fairbridge, R., 1980. The estuary: its definition and geodynamic cycle. In: Research Groups of the Andalusia Board (RNM-183, RNM- Olausson, E., Cato, I. (Eds.), Chemistry and Biogeochemistry of Estuaries. 238, and RNM-276). This paper is a contribution to the IGCP John Wiley and Sons, Chichester, pp. 1–35. 396, 437, and 495. Fernańdez Caliani, J.C., Ruiz, F., Galań, 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. References 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. Abrantes, F., Lebreiro, S., Rodrigues, T., Gil, I., Bartels-Jońsdo´ttir, H., Oliveira, Sedimentary Geology 135, 219–230. P., Kissel, C., Grimalt, J.O., 2005. Shallow-marine sediment cores record Goff, J.R., 2006. When is a tsunami not a tsunami? When is it a storm?. In: Gulf climate variability and earthquake activity off Lisbon (Portugal) for the last Coast Association of Geological Societies, 56th Conference. Lafayette, 2000 years. Quaternary Science Reviews 24, 2477–2494. Louisana, September 25–27 (Abstracts). Allen, H.D., 2003. A transient coastal wetland: from estuarine to supratidal Gonza´lez Delgado, J.A., Andre´s, I., Sierro, F.J., 1995. Late Neogene molluscan conditions in less than 2000 years-Boca do Rio, Algarve, Portugal. Land faunas from the Northeast Atlantic (Portugal, Spain, Morocco). Geobios 28, Degradation and Development 14, 265–283. 459–471. Altunel, E., Meghraoui, M., Akyuz, H.S., Dikbas, A., 2004. Characteristics of the Gonza´lez-Regalado, M.L., Ruiz, F., 1996. Les foraminife`res benthiques de la 1912 co-seismic rupture along the North Anatolian Fault Zone (Turkey): baie du sud-ouest de l’Espagne pendant le Neóge`ne supe´rieur : le Mio- implications for the expected Marmara earthquake. Terra Nova 16, 198–204. Plioce`ne de Huelva. Revue de Paleóbiologie 15, 109–120. Banerjee, D., Murray, A.S., Foster, I.D.L., 2001. Scilly Isles, UK: optical dating Gonza´lez-Regalado, M.L., Ruiz, F., Baceta, J.I., Gonza´lez-Regalado, E., of a possible tsunami deposit from the 1755 Lisbon earthquake. Quaternary Munõz, J.M., 2001. Total benthic foraminifera assemblages in the south- Science Reviews 20, 715–718. western Spanish estuaries. Geobios 34, 39–51. Borrego, J., Lo´pez-Gonza´lez, N., Carro, B., 2004. Geochemical signature as Hindson, R.A., Andrade, C., 1999. Sedimentation and hydrodynamic processes paleoenvironmental marker in Holocene sediments of the Tinto river associated with the tsunami generated by the 1755 Lisbon earthquake. estuary (southwestern Spain). Estuarine, Coastal and Shelf Science 61, Quaternary International 56, 27–38. 631–641. Hindson, R.A., Andrade, C., Parish, R., 1998. A microfaunal and sedimentary Borrego, J., Morales, J.A., Pendoń, J.G., 1995. Holocene estuarine facies record of environmental change within the Late Holocene sediments of along the mesotidal coast of Huelva, southwestern Spain. In: Flemming, Boca do Rio (Algarve, Portugal). Geologie in Mijnbouw-Netherlands B.W., Bartholoma, A. (Eds.), Tidal Signatures in Modern and Ancient Journal of Geosciences 77, 311–321. Sediments, vol. 24. International Association of Sedimentologists (Spe- Kontopoulos, N., Avraimidis, P., 2003. A late Holocene record of environmental cial Publication), pp. 151–170. changes from the Aliki lagoon, Egion, North Peloponnesus, Greece. Qua- Borrego, J., Morales, J.A., De La Torre, M.L., Grande, J.A., 2002. Geochemical ternary International 111, 75–90. characteristic of heavy metal pollution in surface sediments of the Tinto and Lario, J., 1996. U´ ltimo y Presente Interglacial en el a´rea de conexioń Atlańtico- Odiel river estuary (southwestern Spain). Environmental Geology 41, 785– Mediterrańeo: variaciones del nivel del mar, paleoclima y paleoambientes. 796. Ph.D. Thesis. Universidad Complutense de Madrid. Budillon, F., Esposito, E., Lorio, M., Pelosi, N., Porfido, S., Violante, C., 2005. Levin, B.W., Sasorova, E.V., 2002. On the 6-year tsunami periodicity in the The geological record of store events over the last 1000 years in the Salerno 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. Ruiz, F., Rodrı´guez-Ramı´rez, A., Caćeres, L.M., Rodrı´guez Vidal, J., Carretero, Sedimentary record of a tsunami during Roman times, Bay of Cadiz, Spain. M.I., Abad, M., Olıás, M., Pozo, M., 2005. Evidences of high-energy events Journal of Quaternary Science 17, 623–631. in the geological record: Middle Holocene evolution of the southwestern Luque, L., Lario, L., Zazo, C., Goy, J.L., Dabrio, C.J., Silva, P.G., 2001. Donãna National Park. Palaeogeography, Palaeoclimatology, Palaeoecol- Tsunami deposits as paleoseismic indicators: examples from the Spanish ogy 229, 212–229. coast. Acta Geologica Hispanica 36, 197–211. Ruiz, F., Rodriguez-Ramirez, A., Caćeres, L.M., Rodriguez-Vidal, J., Carretero, McMurty, G.M., Watts, P., Fryer, G.J., Smith, J.R., Imamura, F., 2004. Giant M.I., Clemente, L., Munõz, J.M., Yan˜ez, C., Abad, M., 2004. Late Holocene landslides, megatsunamis, and paleo-sea level in the Hawaiian Islands. evolution of the southwestern Donãna National Park (Guadalquivir Estuary, Marine Geology 203, 219–233. SW Spain): a multivariate approach. Palaeogeography, Palaeoclimatology, Morales, J.A., 1993. Sedimentologıá del estuario del rıó Guadiana (S.O. de Palaeoecology 204, 47–64. Espanã y Portugal). Ph.D. Thesis. Universidad de Huelva. Scheffers, A., Kelletat, D., 2003. Sedimentologic and geomorphologic tsunami Myrow, P., Southard, J.B., 1996. Tempestite deposition. Journal of Sedimentary imprints world-wide. A review. Earth Science Reviews 63, 83–92. Geology 66, 875–887. Scheffers, A., Kelletat, D., 2005. Tsunami relics on the coastal landscape west Nanayama, F., Shigeno, K., Satake, K., Shimokawa, K., Koitabashi, S., of Lisbon, Portugal. Science Tsunami Hazards 23, 3–16. Miyasaka, S., Ishii, M., 2000. Sedimentary differences between the Scott, D.B., Leckie, E.M., 1990. Foraminiferal zonation of Great Sippewissett 1993 Hokkaido-nansei-oki tsunami and the 1959 Miyakojima typhoon salt marsh (Falmouth, Massachusetts). Journal of Foraminiferal Research at Taipei, southwestern Hokkaido, northern Japan. Sedimentary Geology 20, 248–266. 135, 255–264. Stuiver, M., Reimer, P.J., 1993. Radiocarbon calibration program. Rev. 4.2. Nomade, J., Chapron, E., Desmet, M., Reyss, J.L., Arnaud, F., Lignier, V., 2005. Radiocarbon 35, 215–230. Reconstructing historical seismicity from lake sediments (Lake Laffrey, Stuiver, M., Reimer, P.J., Bard, E., Beck, J.W., Burr, G.S., Hughen, K.A., Western Alps, France). Terra Nova 17, 350–357. Kromer, B., McCormac, G., van der Plicht, J., Spurk, M., 1998. INTCAL98 Pe´rez Quintero, J.C., 1989. Introduccioń a los Moluscos onubenses I: Faunı´s- Radiocarbon age calibration 24, 000-0 ca BP. Radiocarbon 40, 1041–1083. tica. Junta de Andalucıá A.M.A. Takashimizu, Y., Masuda, F., 2000. Depositional facies and sedimentary Pujos, M., 1984. Jadammina macrescens,te´moin d’un environnement contra- successions of earthquake-induced tsunami deposits in Upper Pleistocene ignant dans l’estuaire de la Gironde (France). In: Oertli, H. (Ed.), Benthos’ incised valley fills, central Japan. Sedimentary Geology 135, 231–239. 83, Proceedings of the 2nd International Symposium on Benthic Forami- van der Kaars, S., Penny, D., Tibby, J., Fluin, J., Dam, R.A.C., Suparan, P., 2001. nifera, Pau and Bordeaux, pp. 511–517. Late Quaternary palaeoecology, palynology and palaeolimnology of a Rodrı´guez-Ramı´rez, A., Ruiz, F., Caćeres, L.M., Rodrı´guez-Vidal, J., Pino, R., tropical lowland swamp: Rawa Danau, West-Java, Indonesia. Palaeogeo- Munõz, J.M., 2003. Analysis of the recent storm record in the southwestern graphy, Palaeoclimatology, Palaeoecology 171, 185–212. Spanish coast: implications for littoral management. The Science of the Watts, P., 2004. Probabilistic predictions of landslide tsunamis off Southern Total Environment 303, 189–201. California. Marine Geology 203, 281–301. Ruiz, F., 2001. Trace metals in estuarine sediments of southwestern Spain. Williams, M., Wilkinson, I.P., Tappin, D.R., McMurtry, G., Fryer, G.J., 2006. Marine Pollution Bulletin 42, 482–490. The Hawaiian megatsunami of 110 Æ 10 Ka: the use of microfossils in Ruiz, F., Gonza´lez-Regalado, M.L., 1996. Les ostracodes du Golfe Mio- detection. Journal of Micropaleontology 25, 55–56. Plioce`ne du sud-ouest de l’Espagne. Revue de Micropaleóntologie 39, Zazo, C., Goy, J.L., Somoza, L., Dabrio, C.J., Brilvomini, G., Impronta, S., 137–151. Lario, J., Bardaji, T., Silva, P.G., 1994. Holocene sequence of sea-level Ruiz, F., Gonza´lez-Regalado, M.L., Baceta, J.I., Munõz, J.M., 2000. Compara- fluctuations in relation to climatic trends in the Atlantic-Mediterranean tive ecological analysis of the ostracod faunas from low- and high-polluted linkage coast. Journal of Coastal Research 10, 933–945. southwestern Spanish estuaries: a multivariate approach. Marine Micro- Zitellini, N., Chierici, F., Sartori, R., Torelli, L., 1999. The tectonic source of the paleontology 40, 345–376. 1755 Lisbon Earthquake. Annali di Geofisica 42, 49–55. Ruiz, F., Gonzalez-Regalado, M.L., Morales, J.A., 1997. Ecologıá de ostraćo- Zitellini, N., Rovere, M., Terrinha, P., Matias, L., Bigsets, T., 2004. Neogene dos en medios estuarinos: el Subsistema Carreras (rio Guadiana, SO de through Quaternary tectonic reactivation of SW Iberian passive margin. Espanã). Estudios Geolo´gicos 53, 249–262. Pure and Applied Geophysics 161, 565–587.