14C-Dated Charcoal and Sediment Drilling Cores as First Evidence of Holocene Tsunamis at the Southern Spanish Coast (original) (raw)
Related papers
…, 2007
At 2 locations of the southern Spanish coast, we found indications for tsunamis induced by submarine earthquakes. Charcoal, which we sampled in 2 stratified, assumed tsunamigenic sediment (tsunamites) layers at the shore outside the ruins of the Roman city of Baelo Claudia, close to the Strait of Gibraltar (province of Cádiz), and radiocarbon dated, surprisingly turned out to be of identical age, about 465 BP. In the laguna of the Cabo de Gata (province of Almería), we found possible remnants of tsunamites in drilling cores deposited above organic sediments, 14 C dated as 680 ± 30 BP. 14 C age (BP) Equivalent cal age a a See text below.
The sedimentary inventory of tsunamis along the southern Gulf of Cadiz (southwestern Spain)
Zeitschrift f&# 252; r …, 2010
Outcrop evidence and shallow percussion drilling in coastal areas proved sedimentary evidence for paleo-tsunamis along a 50 km long segment of the Atlantic coast of southern Spain. The coast between Barbate and Tarifa yielded several depositional environments to preserve tsunamigenic layers, both on top of rocky cliffs as well as in lagoons, marshlands and along sedimentary beaches. Also, we focused on bays with river inlets, which are most probably sheltered from direct tsunami wave action. In these bays, the Roman villages of Baelo Claudia and Mellaria are situated. We found no evidence for tsunamigenic sediments there. On the other side, the findings of an enigmatic, most probable tsunamite has been encountered upon the cliff along the Barbarte-Zahara de los Atunes beach in various heights above mean sea level. Because only one dark-colored fining-up layer with a paleocurrent direction towards the sea has been found directly resting on folded Betic substratum, we interpret this layer as tsunamigenic back wash sediments. The last major event that affected severely the coast of the Gulf of Cádiz was the 1755 Lisbon tsunami. Reportedly, wave heights reached > 10 m in the study area. So, it is likely that coastal changes and deposition of tsunamigenic sediments in this area occurred, being attributed to this 1755 event. However, also older sedimentary relicts of tsunamis have to be taken into account, because sedimentary cores yield evidence for multiple intercalations.
Sedimentary record of a tsunami during Roman times, Bay of Cadiz, Spain
Journal of Quaternary Science, 2002
Historical data show that the Gulf of Cadiz has been exposed to destructive tsunamis during at least the past 2000 yr. The last tsunami was generated by the AD 1755 Lisbon earthquake, which affected the Atlantic coasts of Spain, Portugal and Morocco. Today, these littoral areas are intensely populated and the expected damage could be much greater. Tsunami studies are of great importance in helping to determine the recurrence interval of these events.
Los depósitos de tsunamis como indicadores paleosísmicos: ejemplos en el litoral español
2001
Tsunamis are usually associated with submarine tectonic activity. Tsunamis transform the shore owing to their erosive and sedimentary capacity. Evidence of tsunamis can be preserved in the geological record for millions of years. The tsunami sedimentary record is a useful tool for obtaining paleoseismic information since it is the only record available that allows us to detect and to analyze ancient offshore seismicity. Three examples of tsunami deposits which contribute to the knowledge of the paleoseismicity in the Gulf of Cádiz are presented. The study of sedimentary deposits of the Valdelagrana spit barrier (Cádiz, Spain) suggests that an event such as the 1755 Lisbon earthquake (Ms 8,5-9) might have occurred ca. 216-218 BC. This is the first time data on the return period of these high magnitude events have been provided.
Morpho-sedimentary evidence of Holocene tsunamis in Southwestern Spain estuaries: a summary
Los estuarios constituyen sistemas costeros excelentes para registrar tsunamis a través de un amplio tipo de evidencias geológicas. Este trabajo revisa y resume las evidencias de tsunamis prehistóricos e históricos en los cuatro principales estuarios del suroeste de España. Las más frecuentes son erosión de playas y retroceso del litoral, ruptura y desbordamiento de flechas arenosas y depósito de capas bioclásticas. En la actualidad, estas características se encuentran particularmente bien estudiadas en los estuarios del Tinto-Odiel, Guadalquivir y Guadalete, mientras que son necesarios trabajos más detallados en el sector de influencia marina del estuario del Río Guadiana.
Geomorphology, 2013
ABSTRACT This paper reviews the sedimentological and geomorphological imprints of prehistoric and historical tsunamis in the four main estuaries of SW Spain. These imprints include beach erosion, filling of intertidal channels, deposition of bioclastic layers, washover fans and reworked aeolian sheets and the breaching of spits and tombolos. Most of these imprints were caused by the 218–209 BC and AD 1755 tsunamis, although evidence of other tsunamis has been identified. In these two events, effects on human populations were severe and diverse, such as human loss of life, changes in coastal settlements and international borders, damage to port infrastructure or flooding of marsh and inhabited areas. New radiocarbon reservoir data were included in order to obtain an approach to the recurrence period of these high-energy events (700–1000 yr) in this area.
Minerals
This paper presents the easternmost mineralogical and geochemical evidence of the 1755 Lisbon tsunami found in the Western Mediterranean. This multidisciplinary analysis of a sediment core obtained in Gibraltar (southern Iberian Peninsula) has allowed us to differentiate a tsunamiite from an old lagoon (The Inundation). This tsunamigenic layer has increased levels of calcite and aragonite and higher concentrations of Ba and ferromagnesian elements in comparison with the underlying lagoonal sediments of this core. This layer is also differentiated by its paleontological record, with the introduction of marine species within this lagoon. The uppermost part of the core includes a transition from swampy/marsh paleoenvironments to terrestrial scenarios, with a final anthropogenic filling occurring during the last century.
Sedimentary record of recent tsunamis in the Huelva Estuary (southwestern Spain)
2008
The coast of the Gulf of Cadiz has been repeatedly struck by tsunamis during the late Holocene and the historic period. Historical documents record at least seven catastrophic tsunamis affecting this coast while others have been detected by oceanic instruments. Nevertheless, very few studies have documented the sedimentary record of these tsunamis in the low-energy coastal environments of the Gulf of Cadiz. The Huelva Estuary is located at the central sector of the Gulf of Cadiz and is a mesotidal estuary fed by the Tinto and Odiel rivers. The mean tidal range of the Huelva Estuary is ca 2 m and the mean significant wave height is ca 0.5 m. The outer part of the estuary is characterized by extensive sand-rich sedimentary bodies of marine origin, whereas the central and inner parts are infilled by muddy, tidally deposited sediment bodies. Recorded within these estuarine sediment bodies are five, laterally continuous shelly units. These units display many of the typical characteristics of tsunami deposits; each typically comprises an erosional base followed by a fining-upwards sequence that begins with the shell accumulation and ends with bioturbated muddy sand. The results of 14 C ages and recent radionuclides accumulation rates in this study illustrate that these five tsunami deposits correspond with known events that occurred in AD 1755, 1531, 949 (1033?), 881, and 395 (381?), all of which are documented in historical sources. r
Tsunamites in lagunas: remains of the 1522 Almeria earthquake (western Mediterranean)
Shallow drilling in the laguna and saline of the Cabo de Gata area proved sedimentary evidence for paleo-tsunamis along the Spanish Mediterranean coast. Several coarse grained intervals with finingup and thinning-up sequences, rip-off clasts, broken shells of lamellibranchs and planktic foraminifera show erosive bases are interpreted as tsunamites .