Late Holocene natural and man induced environmental changes in Western Iberian coast: assessing forcing factors (original) (raw)
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The Holocene 9(3):333-339, 1999
A combined geomorphological, radiocarbon dating, archaeological and historical approach permits a refining of the age of the coastal dune systems related to estuaries in the Gulf of Cadiz. Three dune systems are distinguished in this paper. The oldest one, D1, which accumulated under prevailing WSW winds during the first millennium BC, overlays both the occupational horizons of Late Neolithic-Early Copper Age (fourth millennium BC) and the lithic workshop levels’ (fourth to second millennia BC). The middle dune system, D2, containing both Roman and medieval remains, accumulated between the thirteenth or fourteenth centuries and the seventeenth century AD The youngest D3 system is associated with the time of building of watchtowers in the seventeenth century ad but extends to the present; it is related to SW prevailing winds. We explain the absence of aeolian deposits prior to |2700 cal. BP as the result of trapping of a large part of the sediment supply in the estuaries, which starved the neighboring beaches and aeolian settings. Aeolian accumulation reached significant values when sedimentation in the coastal zone changed from being mainly aggradational in the estuaries (|6500–2700 cal. BP) to mainly progradational in spit barriers and related dunes (post |2700 cal. BP). The present analysis of aeolian systems suggests a non-direct correlation, at least in some cases, between coastal progradation of spit barriers and aridity.
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The Holocene, 2014
A combination of sedimentological, geomorphological, and pedological methods has been used to study a late-Holocene sedimentary sequence in a rock coast sector from NW Spain, with the aim of relating it to storm events and their morphodynamic effects. The sequence contains two coarse beach layers at an elevation of 2.8–3.5 m above the present highest astronomical tide (HAT). Radiocarbon dating revealed that their deposition had begun during 1735–1590 cal. yr BP and has continued until the present. The entire beach system experienced considerable morphological change after 1320–1230 cal. yr BP, with a westward displacement of the beach and a retreat of the sedimentary cliff in the eastern section. The two beach layers seem to have been formed by vertical aggradation of clasts and sand during high-energy storm events, highlighting the role of these events in the formation of sedimentary sequences on the rocky coasts of mid-Atlantic Europe. The effects of a recent storm event, recorded...
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Revista Mexicana de Ciencias Geológicas, 2020
The Doñana National Park is a Biosphere Reserve located within the estuary of the Guadalquivir River (SW Spain). It is mainly composed of extensive fluvio-tidal marshes partially protected by an elongated sandy spit. Three phases have been distinguished in the late Holocene evolution of this spit based on textural, geochemical, palaeontological and, chronological data recorded in a long core (31 m). Phase 1 (890 BCE-218 BCE) is characterized by the alternation of lagoonal silty sediments and slightly polluted marsh deposits, the latter with contamination from thousand-year-old mining. Phase 2 (218 BCE-90 CE) is characterized by several historical tsunamis, which caused the erosion of previous dune systems and the deposit of these sandy sediments on the adjacent bottom of the lagoon. Phase 3 (90 CE-Present) includes a regressive sequence (lagoonal bottommarsh-dune system), with the pollution of lagoonal sediments due to Roman mining activities.
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The coastal zone in which the lagoons of La Mata and Torrevieja (Eastern Spain) developed can be described as a compilation of geo-hazards typical of the Mediterranean realm. This study has focused mainly on those linked to recent tectonics. Extensive use of the amino acid racemization dating method allowed us to establish the evolution of all the geomorphological units differentiated in the area, the most striking manifestation being at the La Mata Lagoon Bar, where MIS 5 deposits settled on MIS 7 sediments along a marked erosive unconformity, thereby attesting coastal uplift between these two stages. In addition, recent uplift processes were reflected on stepped abrasion platforms and, in some cases, enormous boulders were transported over these platforms by extreme surge waves. Furthermore, we obtained feasible evidence that, during the end of MIS 5, an earthquake with an offshore epicenter linked to Torrevieja Fault, Bajo Segura Fault or the set of faults linked to the former, w...
PLOS ONE, 2016
We present a palaeoenvironmental study of the Castelló lagoon (NE Spain), an important archive for understanding long-term interactions between dynamic littoral ecosystems and human management. Combining geochemistry, mineralogy, ostracods, diatoms, pollen, non-pollen palynomorphs, charcoal and archaeo-historical datasets we reconstruct: 1) the transition of the lagoon from a marine to a marginal environment between~3150 cal BC to the 17 th century AD; 2) fluctuations in salinity; and 3) natural and anthropogenic forces contributing to these changes. From the Late Neolithic to the Medieval period the lagoon ecosystem was driven by changing marine influence and the land was mainly exploited for grazing, with little evidence for impact on the natural woodland. Land-use exploitation adapted to natural coastal dynamics, with maximum marine flooding hampering agropastoral activities between~1550 and~150 cal BC. In contrast, societies actively controlled the lagoon dynamics and become a major agent of landscape transformation after the Medieval period. The removal of littoral woodlands after the 8 th century was followed by the expansion of agrarian and industrial activities. Regional mining and smelting activities polluted the lagoon with heavy metals from the~11 th century onwards. The expansion of the milling industry and of agricultural lands led to the channelization of the river Muga into the lagoon after~1250 cal AD. This caused its transformation into a freshwater lake, increased nutrient load, and the infilling and drainage of a great part of the lagoon. By tracking the shift towards an anthropogenically-controlled system around~750 yr ago, this study points out Mediterranean lagoons as ancient and heavily-modified systems, with anthropogenic impacts and controls covering multi-centennial and even millennial timescales. Finally, we contributed to the future construction of reliable seashell-based chronologies in NE Spain
Natural Hazards
The coastal zone in which the lagoons of La Mata and Torrevieja (Eastern Spain) developed can be described as a compilation of geo-hazards typical of the Mediterranean realm. This study has focused mainly on those linked to recent tectonics. Extensive use of the amino acid racemization dating method allowed us to establish the evolution of all the geomorphological units differentiated in the area, the most striking manifestation being at the La Mata Lagoon Bar, where MIS 5 deposits settled on MIS 7 sediments along a marked erosive unconformity, thereby attesting coastal uplift between these two stages. In addition, recent uplift processes were reflected on stepped abrasion platforms and, in some cases, enormous boulders were transported over these platforms by extreme surge waves. Furthermore, we obtained feasible evidence that, during the end of MIS 5, an earthquake with an offshore epicenter linked to Torrevieja Fault, Bajo Segura Fault or the set of faults linked to the former, w...
Progress in Quaternary archive studies in the iberian peninsula, 2015
Many of the coastal changes occurred during the mid-late Holocene have influenced run-off and sediment transport, as sea-level rising and terrestrial environmental changes. The coastal plains and the near-shore environments offer a very dynamic archive that holds the possibility of a better understanding of the relationships between marine and terrestrial records. As many key archaeological sites are located at coastal settings, the land-sea interaction is important for a better understanding of pre-historical and historical human settlements. This work therefore aims to provide a multidisciplinary platform to define the relationship between the coastal environmental evolution and the human population of the Huelva estuary (Gulf of Cádiz) during the early centuries of Roman occupation
Quaternary International, 2011
Various neotectonic faults were deduced in Puerto de Mazarrón (Murcia), together with a series of eustatic and climatic phases dating from at least 13,600 years ago. These were responsible for intense sedimentary morphodynamics that had significant environmental repercussions in this area during the Middle Holocene. These phases were identified in a former estuary and two coastal lagoons. This multidisciplinary study, involving geologists, geomorphologists, archaeologists and palynologists, integrated a variety of methods including borehole drilling, interpretation of old aerial photograms, drawing of geological and geomorphological maps, sediment analysis, malacology, palynology, 14 C dating, and analysis of stable isotopes in water samples.