El registro de eventos energéticos marinos en la bahía de Cádiz durante épocas históricas

Abstract

The bay of Cádiz is a coastal area intensively occupied during prehistorical and historical times from which many archaeological remains have been preserved. The bay is a low coast characterized by several spit-barrier systems which close wide estuarine marshes. This kind of coastal environment is especially vulnerable to marine energetic events, like storms and tsunamis, which have occurred in the region during the late Holocene with some regularity. The present work summarizes the different morphosedimentary records of historical marine events identified in the Bay up to date. New chronological and stratigraphical data are presented, obtained from drills, together with different geoarchaeological indicators of historical marine events identified along the Bay. Special attention is paid on the effects produced on the Valdelagrana spit-barrier, where the geometry and age of different historical beach ridges reveal the onset of at least three very energetic events, probably of tsunamigenic origin: one on 2700-2300 cal BP, a second one by the end of the IX century AD and the third one in 1755 AD. The two first events caused deep geomorphological modifications, like river captures, onset of new beach ridge systems, and coastal lowering. Archaeological data indicate that economical effects and infrastructure damage produced by these events conditioned later human occupation and related activities.

A Major Earthquake and Tsunami in the Gulf of Cadiz in the Sixth Century B.C.? A Review of the Historical, Archaeological, and Geological Evidence

“…A similar high-energy marine event, dating to between 2700-2400 cal BP (Lario et al, 2010) or 2700-2500 BP (Alonso et al, 2015;Gracia et al, 2022), which caused a wide breach in the spit barrier of Valdelagrana in the central sector of the morphosedimentary unit H2, and led to the reorganisation of the back-barrier drainage system, has been recorded in the estuary of the river Guadalete.…”

Battles beneath the Sea: Phoenician Votive Offerings as a Possible Religious Response to Extreme Marine Events in the Gulf of Cadiz

“…5. Lastly, a similar event has been documented in the estuary of the Guadalete, which produced a large breach in the ancient spit bar of Valdelagrana and a reorganization of the drainage system of the estuary, owing to one or several high-energy marine events (Alonso Villalobos et al 2015), dated between 2700 and 2400 cal BP (Lario et al 2010: 305, table 2) or between 2700 and 2500 BP (Alonso Villalobos et al 2015;Gracia, Alonso, and Aparicio 2022: 158). Although these authors recognize the difficulty of specifying the nature and the exact moment of that event, they call attention to the occurrence, between 2760 and 2560 BP, of a period of major climate changes in middle latitudes of the North Atlantic, associated with violent sea storms in southern and central Europe (Martín Puertas et al 2012).…”

Storm surge and tsunami deposits along the Moroccan coasts: state of the art and future perspectives

“…For example, a sudden interruption of garum production in the 3rd century CE has been reported in several coastal archaeological sites in Spain, Portugal and Morocco. The origin is uncertain and may be political (fall of the Roman Empire) or natural, related to one or more extreme marine events (Alonso et al 2015;Trakadas 2015;González-Regalado et al 2018).…”