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SEDIMENTARY RECORD OF SEDIMENTARY RECORD OF HISTORICAL TSUNAMIS IN HISTORICAL TSUNAMIS IN THE BAY OF CADIZ (SPAIN)THE BAY OF CADIZ (SPAIN)
Javier LarioUNED(Universidad Nacional de Educacion a Distancia, Madrid)Museo Nacional de Ciencias Naturales, CSIC (Madrid)[email protected]
Marrakech, 07
H4 spit barrier tsunami deposits - H4 spit barrier tsunami deposits - 1755 Lisbon tsunami1755 Lisbon tsunami
Described by Dabrio et al., 1997; Luque at al., 1999, 2000•At least 4 washover fans•19 cores•3 sandy units related with 3 wave flooding
H3 spit barrier tsunami depositsH3 spit barrier tsunami deposits
•10 washover fans•1900-2300 yrBP
TAP-01-1
TAP-01-2
TAP-01-3
Grain sizeGrain size
TAP-1-02TAP-1-02
TAP-1-01TAP-1-01
Doñana spit barrier high-energy/tsunami depositsDoñana spit barrier high-energy/tsunami deposits
GEOLOGICAL RECORDGEOLOGICAL RECORD
GEOLOGICAL RECORDGEOLOGICAL RECORD
•During Late Holocene: Almost two tsunamis in Gulf of Cadiz with destructive effects
•Geomorphological, sedimentological and palaeontological record, that support the historical and archeological record
•Essential to calculate recurrence periods
Tsunami
Storm
Abanicos aluviales asociados a rotura de flechas y barras de playa Depósitos mas finos tierra adentro
Granulometría mas fina tierra adentro Contacto basal erosivo
Bloques de gran tamaño Extensión de los depósitos tierra adentro Una o más secuencias granodecrecientes, a veces homogéneas Intraclastos del material subyacente Estructuras de carga en la base Imbricación bidireccional Mala selección (de arcillas a bloques) Estructuras sedimentarias raramente presentes Cambios importantes en la red de drenaje Incremento susceptibilidad magnética Incremento en elementos geoquímicos indicativos de ambiente marino
Relativamente pequeña extensión del proceso tierra adentro Una secuencia granodecreciente u homogénea No descrito No descrito Imbricación unidireccional Relativa mejor selección Presencia de estructuras sedimentarias (estratificación planar) No descrito No descrito, pero predecible No descrito, pero predecible
Presencia de fauna marina Mezcla de especies marinas y de estuario/ agua dulce
Fragmentos de plantas Mayoría de restos de fauna marina bien Restos de fauna marina mal preservados
Registro geológico
(Andrade, 1992; Kortekaas, 2002; Tuttle et al., 2004; Kortekass & Dawson, 2007)
ca. 7000 CalBP High energy event. storm?ca. 5600-5300 CalBP High energy event. storm?ca. 4200-4000 CalBP High energy event. ca. 2700-2400 CalBP High energy event: tsunami + storm surge
alla round the coastTsunami: sure in Valdelagrana at ca.2300-2200 CalBP (Luque et al., 2003)
correlation possible with others event in the coastca. 2000 CalBP High energy event. ca. 1500 CalBP High energy event. 1755 AD Tsunami (Lisbon earthquake).
Not always we founf geological record.Lack in dating sediments associated with this
event
High energy events in Gulf of CadizHigh energy events in Gulf of Cadiz
No enough data to calculate recurrence periodsNeed to be correlated with other records (tsunamites?)
Future
Otros Eventos de Alta Energía
Rio Piedras estuaryRio Piedras estuary
Huelva
Tinto-OdielEstuary
19 cores(6 to 23 m)
Past/Now/NextPast/Now/Next
•LithologyLithology•Grain size (high resolution)Grain size (high resolution)•Environmental magnetismEnvironmental magnetism•Palaeontology (micro and micro)Palaeontology (micro and micro)•GeochemistryGeochemistry•MineralogyMineralogy•Radiocarbon datingRadiocarbon dating
Identification of high energy eventIdentification of high energy eventDifferentiate tsunamis from stormsDifferentiate tsunamis from storms