GEOARCHAEOLOGY AND HOLOCENE PALAEOGEOGRAPHY by Francisco Borja Barrera
Itálica. Investigaciones arqueológicas en la Vetus Urbs, 2021
The application of new technologies to produce continuous surfaces by the interpolation of discre... more The application of new technologies to produce continuous surfaces by the interpolation of discrete points with three-dimensional information, together with the integration of edapho-sedimentary, geomorphological and archaeological data under the principles of the geoarchaeology have allowed: first, reconstruct the paleotopographies and the stages of growth of the mound of Itálica, particularly of the area called Cerro de San Antonio; and, second, to determine the main phases of palaeogeographic evolution and urban landscape changes of this urban hill. We conclude that the San Antonio mound can exceed 5 m thick; that it is fundamentally make up by architectural remains and occupation deposits of Roman times, while occupation deposits of previous times only occasionally turn up; and that its slopes, both those that descend towards the east, close to theatre, and those that go south, downward to the calle Real small valley, show features of an intense human handling (embankments, containment walls, terraces...).
Geoarchaeology as Geoarchaeology, 2020
We think on the current role of Geoarcheology. It has seemed to us that sharing our point of view... more We think on the current role of Geoarcheology. It has seemed to us that sharing our point of view on this matter could help to encourage the debate on a scientific dield that, like it or not is still a budding discipline. We defend that Geoarcheology can have its own object of study, objectives and methodological procedure and that, therefore, it can act scientifically as a true Geoarcheology, and not necessarily as a practice derived from Archeology or Geology.
RIVERA DE LA ALGABA VERSUS RIVERA DE HUELVA. DOS SIGLOS DE CAUCES COMPARTIDOS, 2020
Rivers no bedrock courses essentially depends on the variety and temporal scope of the hydro-geom... more Rivers no bedrock courses essentially depends on the variety and temporal scope of the hydro-geomorphological processes registered in the alluvial plains. According by the nature of the flows and their morphosedimentary incidence, rectilinear, meandering, braided, anastomosed channels, etc. may appear, which can, over time, evolve from one type to another. Many of the changes in the riverbeds occur so quickly that they are often noticeable on human scale. Neck cut-off, chute cut-off, avulsions... are phenomena that can occur even abruptly, in the course of large avenues. During the last thousands of years, medium-low channel of the Guadalquivir has belonged to the meandering rivers kind. Its recent evolution has given rise to a landscape full of, as the Spanish say, curvas, tornos, puntas, vueltas, madres viejas, etc., as it has been recorded in toponymy, as well as in countless graphic and cartographic documents of the past. Direct comparison of these historical images in order to establish the chronosequence and evolutionary milestones of river landscapes is not, however, a very common practice. Less if, as is done in our contribution, graphic documentation, in addition to being subjected to a critical analysis from both a technical and historical point of view, is geo-referenced and digitized, and analyzed in order to understand how and when they recorded the main hydrographic changes of the Guadalquivir (also called in this stretch Rivera de La Algaba) and of the final section of the Rivera de Huelva, its tributary. From our study it appears that for two centuries, from 1745 to 1945, the Rivera de La Algaba (or Guadalquivir River to the north of Seville) began to flow through the old channel that surrounded the Quijano Island; that this great lathe was strangled in the late eighteenth century (Corte de la Mercadera), which takes advantage of the Rivera de Huelva to run through it for decades; and, finally, that the aforementioned tributary returned to circulate through the section abandoned by the Guadalquivir to the north of the "island", but in this case in the opposite direction.
El trazado de las corrientes fluviales depende, esencialmente, de la variedad y el alcance temporal de los procesos hidro-geomorfológicos registrados por las llanuras aluviales. Según sea el carácter de los flujos y la respuesta morfo-sedimentaria a los mismos, podemos tener cauces rectilíneos, meandriformes, trenzados, anastomosados, etc., los cuales, con el paso del tiempo, pueden evolucionar de un tipo a otro. Muchas de las modificaciones sufridas por los cauces se dan con tanta rapidez que, a menudo, son perceptibles a escala humana. Capturas entre cauces, estrangulamientos o acortamientos de meandros, bifurcaciones… son fenómenos que pueden darse incluso de forma abrupta, en el transcurso de grandes avenidas. Durante los últimos miles de años, el cauce medio-bajo del Guadalquivir ha pertenecido a la categoría de los ríos meandriformes. Su evolución reciente ha dado lugar a un paisaje repleto de curvas, tornos, puntas, vueltas, madres viejas, etc., como así ha quedado registrado en la toponimia, así como en infinidad de documentos gráficos y cartográficos del pasado. La comparación directa de estas imágenes históricas al objeto de establecer la cronosecuencia y los hitos evolutivos de los paisajes fluviales no es, sin embargo, una práctica muy común. Menos si, como se hace en la presente contribución, la documentación gráfica, además de ser sometida a un análisis crítico tanto desde el punto de vista técnico como histórico, es georreferenciada y digitalizada, y se analiza con el fin de comprender cómo y cuándo se registraron los principales cambios hidrográficos del Guadalquivir (o Rivera de La Algaba) y del tramo final del Rivera de Huelva, su afluente. De nuestro estudio se desprende que durante dos siglos, de 1745 a 1945, por el antiguo cauce que rodeaba la Isla de Quijano empezó fluyendo la Rivera de La Algaba; que este gran torno quedó estrangulado a finales del siglo XVIII (Corte de la Mercadera), lo que aprovecha la Rivera de Huelva para discurrir a su través durante décadas; y, por último, que el mencionado afluente volvió a circular por el tramo abandonado por el Guadalquivir al norte de la "isla", pero en este caso en sentido contrario.
Caura. Arqueología en el estuario del Guadalquivir (Ed. EUS), 2018
This paper contributes to the study of the paleogeographic evolution of the lower Guadalquivir du... more This paper contributes to the study of the paleogeographic evolution of the lower Guadalquivir during the Late Holocene. From a geoarchaeological approache, the historical landscapes of the floodplains of Santiponce (Italica), Seville (Hispalis) and Coria del Río (Caura) are reinterpreted.
Boletín Geológico y Minero (IGME), 2018
Even before Italica was founded by the Romans at the end of the third century BC, this settlement... more Even before Italica was founded by the Romans at the end of the third century BC, this settlement maintained a close relationship with the morph-dynamic evolution of the lower Guadalquivir River (SW Andalusia, Spain), especially with the lateral channel displacements. In order to reconstruct the palaeogeographic evolution of the alluvial area of Itálica during the second half of the Holocene, our research has focused on the study of the fluvial palaeoforms and the alluvial soil-sedimentary sequence, with special emphasis on the analysis of the geoarchaeological records. Ancient maps and aerial photographs of various scales and diverse dates have been interpreted. Borehole cores and profiles, manually or mechanically opened, have also been done to obtain samples for laboratory tests of the representative floodplain soils and sediments. The chronologies provided by the archaeological record were completed with several radiocarbon dates. From these results we propose a possible solution at a local level to the traditional discussion about the existence and location of the ancient harbour of Italica; and for the alluvial plain as a whole, a double alternating palaeogeographic sequence trending to millennial-submillennial scale has been reached. The first one occurring controlled by hydrologic and climatic factors, modulated by a prolonged and extended human pressure on the basin, and showing a succession of four main stages characterized by the predominance of alluvial filling (4833-3206 cal BP; 3130-1989 cal BP; 1620 cal BP- XI century AD; and around the last 500 years), which are separated by periods of stability that favored alluvial soils formation; meanwhile, the second sequence presents short-time terms prone to riverbed design shifting (period prior to Late Bronze; Roman-republican era; central Middle Age), also separated by lengthy phases of morph-hydrographic stability. In the latter case the main factor does not seem to be, as in the first of those, hydro-climatic shifts and land use changes, but rather the last small regional fluctuations of sea level that came with the second part of the Holocene.
The study of the edafo-sedimentary sequence of the low Guadalquivir floodplain allows extrapolati... more The study of the edafo-sedimentary sequence of the low Guadalquivir floodplain allows extrapolating Palaeoenvironmental conclusions to the neighboring funerary complex of the Copper Age of Valencina-Guzmán (Seville). For that purpose, the alluvial archives adjacent to the Montelirio tholos site (Santiponce-Seville sector) have been studied, with special emphasis on the analysis of climatic, hydro-geomorphological, anthropic and eustatic factors recorded during the second half of the Holocene close the mouth of the Guadalquivir. Results allow to establish the existence of four large phases characterized by a predominance of alluvial sedimentation (4833-3206 cal BP; 3130-1989 cal BP, 1620 cal BP-XI century AD, and last 500 years), separated by as many episodes of stability favorable to the development of alluvial soils. From the Palaeoenvironmental point of view, it is concluded that only the first of these alluvial phases, (between the Chalcolithic and the Bronze Age), can be unequivocally associated with arid and cold conditions, assuming that these climatic features could be the most adequate for a higher incidence of floods and the accumulation of sediments. However, the strong anthropic impact recorded in this period in the Guadalquivir valley suggests that part of this aridity conditions and this tendency towards sedimentary accumulation also has to do with the human impact on vegetation cover and soils.
Two specific problems concerning to tholos of montelirio (Castilleja de Guzmán, Seville, Spain),... more Two specific problems concerning to tholos of montelirio (Castilleja de Guzmán, Seville, Spain), which features a large passage roofed by stone slabs, are investigated. Firstly, we analyse the main geologic features (lithology, petrography, structures...) of the 42 capstones that cover its long corridor (over 36 m in length and an average width of 1.8 m); among these rocks, 29 of them are sandstones (67.4%), 10 are grey or green shale (23.2%) and three are granite (6.9%). Secondly, we locate potential source areas of these materials, concluding that both granites and shales, either grays or green, come from palaeozoic outcrops located on the southern edge of the Iberian Massif (Sierra Morena, around Gerena-Aznalcóllar, Sevilla), while sandstones, most likely, came from of the outcrops of Mio-Pliocene facies of the El Aljarafe marine sequence.
The Working Group defines Geoarchaeology as “the geosciences and geographical methods and
techniq... more The Working Group defines Geoarchaeology as “the geosciences and geographical methods and
techniques applied to prehistory, archaeology, and history”. Its aim is to promote Geoarchaeology in
an open-minded way and from an interdisciplinary point of view. (Fouache et al. 2010: 307)
The Piedras River marshland and El Rompido spit bar is a Natural Site in close proximity to two o... more The Piedras River marshland and El Rompido spit bar is a Natural Site in close proximity to two of the most polluted rivers in the world: the Tinto and Odiel Rivers. The aim of this study is to determine the degree of contamination of this Natural Site using a variety of pollution indices. At this site the Holocene infilling sequence is recorded and applied to a study of the pollution history and the possible impacts of human activity. The deposi-tional history of the Piedras River estuary during the Holocene recorded open marine conditions at ca. 6500 calBP when sea-level was at its Holocene maximum. To study the pollution of the estuary during the Holocene, catchment background geochemistry was established using samples that pre-date human activity (agriculture and mining). Additionally, the sedimentary environment was reconstructed throughout the Holocene; comparison of pollution levels is interpreted to be more reliable if the sedimentary environment has remained similar throughout the depositional record. Results show that, despite being located nearby very polluted estuaries, the Piedras River marshland contains unpolluted sediments mainly because of the small catchment area relative to that of neighbouring more polluted rivers, and thus has not been affected by human activity such as mining.
The signifcance of seolian sand accumulations located in the Mengabril areq (middle Gusdiann riae... more The signifcance of seolian sand accumulations located in the Mengabril areq (middle Gusdiann riaer oalley, Spnin) is discussed on the basis of morph-sedimentary dnta, optically stimulqted luminescence (OSL) dating, and nrchqeological record. Mengabril sands are composed mninly of sand-sized particles (80,32%), houteaer, due to its high content of silt (12,18%) and clay (7,5%) can consider them ss so-called clay-dunes (or maybe nte should talk rother of "silt-dunes"?). This kind of mixed dune hoae been described elsewhere in the lberian Peninsula (maínly in La Mancha), but while there haae been dnted before the mid-Holocene, the dates obtained by OSL and the archneological record in Mengabril place them specifically during the nrid periods located in the Chotcolithic, Romsn times until Antonine dynasty and from early to high Middle Age.
El teatro romano de Itálica se adosa al flanco oriental del cerro de San Antonio, una de las suav... more El teatro romano de Itálica se adosa al flanco oriental del cerro de San Antonio, una de las suaves elevaciones sobre las que se extiende el actual casco histórico de Santiponce, localidad sevillana situada a unos 6 km de la antigua Hispalis. Dicho edificio emplaza su graderío sobre la ladera de la citada colina, labrada sobre las Margas Azules del Mioceno superior, y su espacio escénico sobre la cobertera aluvial del Holoceno-superior que conforma la vega del Guadalquivir
Progress in Quaternary archive studies in the Iberian Peninsula, 2015
Una visión global del Cuaternario. El hombre como condicionante de procesos geológicos (J. P. Galve, J. M. Azañón, J. V. Pérez Peña y P. Ruano, Eds.): XIV Reunión Nacional de Cuaternario, Granada (España)., Jun 2015
The significance of aeolian sand accumulations located in the Mangabril area (middle Guadiana riv... more The significance of aeolian sand accumulations located in the Mangabril area (middle Guadiana river valley, Spain) is discussed on the basis of morph-sedimentary data, optically stimulated luminescence (OSL) dating, and archaeological record. Mengabril sands are composed mainly of sand-sized particles (80,32%), however, due to its high content of silt (12,18%) and clay (7,5%) can consider them as so-called clay-dunes (or maybe we should talk rather of “silt-dunes”?). This kind of mixed dune have been described elsewhere in the Iberian Peninsula (mainly in La Mancha), but while there have been dated before the mid-Holocene, the dates obtained by OSL and the archaeological record in Mengabril place them specifically during the arid periods located in the Chalcolithic, Roman times until Antonine dynasty and from early to high Middle Age.
Itálica 02, 2012
A comprehensive model of the subsurface water running is proposed for the Roman Theatre of Italic... more A comprehensive model of the subsurface water running is proposed for the Roman Theatre of Italica (SW Spain). Using data from several cores (8 to 20 m depth), some of them equipped with piezometers, we analyze the sedimentary filling (lithofacies, contacts, chronologies, archaeological record...) identifying different types of groundwater flow. Furthermore, we study the origin of the water and, finally, the water dynamic is evaluated from spring to summer of 2011, compared with daily rainfall of previous same seasons. It is concluded that there are three different kinds of flows which can flood the orchestra area alternately along the annual cycle.
Human records of recent geological evolution in the Mediterranean Basin. Historical and archaeological evidence
To relate tectonic impact to the environmental history of ancient populated areas, human archives... more To relate tectonic impact to the environmental history of ancient populated areas, human archives and geo-archives must be analyzed, evaluated and compared. Aside from historical references, the most common human record of large earthquakes is the generation of horizons of destruction (and/or demolition) among the different archaeological layers of ancient cities. However, in spite of the conspicuous interferences of large seismic events with human activities in the Mediterranean, permanent landscape changes linked to active tectonics are extremely rare
Setubal Arqueologica, 1997
Actas IV Jornadas sobre teledetección y geofísica aplicadas a la arqueología , 1996
Se analizan los episodios de arranque de la flecha litoral de Valdelagrana en estuario del Guadal... more Se analizan los episodios de arranque de la flecha litoral de Valdelagrana en estuario del Guadalete (Cádiz) a partir del registro geoarqueológico.
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GEOARCHAEOLOGY AND HOLOCENE PALAEOGEOGRAPHY by Francisco Borja Barrera
El trazado de las corrientes fluviales depende, esencialmente, de la variedad y el alcance temporal de los procesos hidro-geomorfológicos registrados por las llanuras aluviales. Según sea el carácter de los flujos y la respuesta morfo-sedimentaria a los mismos, podemos tener cauces rectilíneos, meandriformes, trenzados, anastomosados, etc., los cuales, con el paso del tiempo, pueden evolucionar de un tipo a otro. Muchas de las modificaciones sufridas por los cauces se dan con tanta rapidez que, a menudo, son perceptibles a escala humana. Capturas entre cauces, estrangulamientos o acortamientos de meandros, bifurcaciones… son fenómenos que pueden darse incluso de forma abrupta, en el transcurso de grandes avenidas. Durante los últimos miles de años, el cauce medio-bajo del Guadalquivir ha pertenecido a la categoría de los ríos meandriformes. Su evolución reciente ha dado lugar a un paisaje repleto de curvas, tornos, puntas, vueltas, madres viejas, etc., como así ha quedado registrado en la toponimia, así como en infinidad de documentos gráficos y cartográficos del pasado. La comparación directa de estas imágenes históricas al objeto de establecer la cronosecuencia y los hitos evolutivos de los paisajes fluviales no es, sin embargo, una práctica muy común. Menos si, como se hace en la presente contribución, la documentación gráfica, además de ser sometida a un análisis crítico tanto desde el punto de vista técnico como histórico, es georreferenciada y digitalizada, y se analiza con el fin de comprender cómo y cuándo se registraron los principales cambios hidrográficos del Guadalquivir (o Rivera de La Algaba) y del tramo final del Rivera de Huelva, su afluente. De nuestro estudio se desprende que durante dos siglos, de 1745 a 1945, por el antiguo cauce que rodeaba la Isla de Quijano empezó fluyendo la Rivera de La Algaba; que este gran torno quedó estrangulado a finales del siglo XVIII (Corte de la Mercadera), lo que aprovecha la Rivera de Huelva para discurrir a su través durante décadas; y, por último, que el mencionado afluente volvió a circular por el tramo abandonado por el Guadalquivir al norte de la "isla", pero en este caso en sentido contrario.
techniques applied to prehistory, archaeology, and history”. Its aim is to promote Geoarchaeology in
an open-minded way and from an interdisciplinary point of view. (Fouache et al. 2010: 307)
El trazado de las corrientes fluviales depende, esencialmente, de la variedad y el alcance temporal de los procesos hidro-geomorfológicos registrados por las llanuras aluviales. Según sea el carácter de los flujos y la respuesta morfo-sedimentaria a los mismos, podemos tener cauces rectilíneos, meandriformes, trenzados, anastomosados, etc., los cuales, con el paso del tiempo, pueden evolucionar de un tipo a otro. Muchas de las modificaciones sufridas por los cauces se dan con tanta rapidez que, a menudo, son perceptibles a escala humana. Capturas entre cauces, estrangulamientos o acortamientos de meandros, bifurcaciones… son fenómenos que pueden darse incluso de forma abrupta, en el transcurso de grandes avenidas. Durante los últimos miles de años, el cauce medio-bajo del Guadalquivir ha pertenecido a la categoría de los ríos meandriformes. Su evolución reciente ha dado lugar a un paisaje repleto de curvas, tornos, puntas, vueltas, madres viejas, etc., como así ha quedado registrado en la toponimia, así como en infinidad de documentos gráficos y cartográficos del pasado. La comparación directa de estas imágenes históricas al objeto de establecer la cronosecuencia y los hitos evolutivos de los paisajes fluviales no es, sin embargo, una práctica muy común. Menos si, como se hace en la presente contribución, la documentación gráfica, además de ser sometida a un análisis crítico tanto desde el punto de vista técnico como histórico, es georreferenciada y digitalizada, y se analiza con el fin de comprender cómo y cuándo se registraron los principales cambios hidrográficos del Guadalquivir (o Rivera de La Algaba) y del tramo final del Rivera de Huelva, su afluente. De nuestro estudio se desprende que durante dos siglos, de 1745 a 1945, por el antiguo cauce que rodeaba la Isla de Quijano empezó fluyendo la Rivera de La Algaba; que este gran torno quedó estrangulado a finales del siglo XVIII (Corte de la Mercadera), lo que aprovecha la Rivera de Huelva para discurrir a su través durante décadas; y, por último, que el mencionado afluente volvió a circular por el tramo abandonado por el Guadalquivir al norte de la "isla", pero en este caso en sentido contrario.
techniques applied to prehistory, archaeology, and history”. Its aim is to promote Geoarchaeology in
an open-minded way and from an interdisciplinary point of view. (Fouache et al. 2010: 307)
reinterpreted after a refinement of the available geochronology by means of optically stimulated luminescence (OSL) dating.
New data come from the analysis of soft sediment deformation, palaeosols, geomorphological mapping, and published seismic
surveys on the onshore and offshore Gulf of Cadiz.
The present structure of El Abalario dome resulted from the complex interaction of littoral-catchment processes and sealevel
changes upon an emergent coastal plain, conditioned by the upwarping of the underlying Pliocene–Pleistocene
prograding deltaic sequence. Upwarping is probably related to escape of over-pressurized fluids, accompanied by dewatering,
prior to (?) and during OIS (Oxygen Isotopic Stage) 5. Continued upwarping produced the large NW–SE gravitational fault
of Torre del Loro (TLF) in the southwestern flank of the dome, roughly parallel to the present coastline during OIS 5–OIS 4.
The resulting escarpment favoured the accumulation of aeolian sand dunes (units U1, U2, and U3) from OIS 5 to early OIS
1. Unit U1 (OIS 5) ends upwards in a supersurface with a thick weathering profile that suggests moist and temperate climatic
conditions. Unit U2 accumulated mainly during OIS 4 and OIS 3 with prevailing W/E winds. The supersurface between U2"
drill cores, logs, trenches, and 38 new radiocarbon data, and the results compared with the shelf. The Odiel, Tinto and
Guadalete Rivers deposited conglomerates during a highstand that did not reach the present sea level dated at ca. 25–30 ka
Isotopic Stage IS. 3., corresponding to a relatively humid period in the area. Rivers incised these coarse-grained deposits
during the last main lowstand at ca. 18 ka, when sea level dropped to y120 m and the coastline lay 14 km seawards from
the present. The erosional surface is a sequence boundary and the flooding surface of the postglacial eustatic rise, overlain
by the valley fill deposits of the transgressive and highstand phases of the last fourth- and fifth-order depositional sequences
recognised in the shelf. The first marine influence in the estuaries during the transgression occurs at y25ry30 m at ca.
10,000 years BP. According to fossil assemblages, the transgressed basins changed from brackish to more open marine as
the sea rose until ca. 6500 years BP, when it reached the maximum flooding and the sandy estuarine barriers ceased to
retrograde toward the muddy central basins. Then, the rate of eustatic rise decreased drastically, and the estuarine filling
followed a two-fold pattern governed by the progressive change from vertical accretion to lateral centripetal. progradation.
At ca. 4000 years BP the fluvial input surpassed the already negligible rate of rise, causing partial emergence of tidal flats
and spit barriers in the largely filled estuarine basins. Prevalence of coastal progradation upon vertical accretion at ca. 2400
years BP caused accelerated expansion of tidal flats and rapid growth of the sandy barriers. Further changes since the 16th
century reflect widespread anthropic impacts. q2000 Elsevier Science B.V. All rights reserved.
Francisco Borja Barrera (2016)
Con los paisajes ya desaparecidos ocurre que, para hacerse una idea cabal de cómo fueron tiempo atrás, además de describirlos conviene representarlos gráficamente, expresarlos de forma visible, substanciarlos mediante imágenes. Pero dado que la reconstrucción de los paisajes históricos se acomete desde el conocimiento y las técnicas disponibles en cada época, y éstas cambian con el paso del tiempo, también las imágenes del pasado han de renovarse, aunque a veces se resistan a ser substituidas. La idea del río Baetis recorriendo la vega de Hispalis con dos cauces que dejan una isla interfluvial entre ellos (popularizada a partir de la publicación de la tesis doctoral F. Collantes de Terán en 1977), es un buen ejemplo de lo que decimos, dado que los recientes estudios geoarqueológicos han demostrado que esta disposición de los cauces del Guadalquivir nunca se dio en época romana.
Con la presente charla, "Geoarqueología y Paisaje Histórico de la Vega de Sevilla (Spal-Hispalis-Ishbilia)", no sólo intentaremos recrear cómo era la topografía de Sevilla en el momento de su nacimiento como ciudad (Spal), sino además comprender cómo cambió su modelado a lo largo del tiempo, y a qué razones obedecieron dichas modificaciones. De manera particular nos centraremos en conocer si fueron uno o varios los cauces fluviales que discurrieron por la vega de Sevilla durante la Antigüedad y la Edad Media, cuáles fueron sus trazados en cada momento, cuáles las casusas de su mudanza y cómo estas circunstancias condicionaron la evolución de la forma urbana. De dar respuesta a cuestiones como estas se encarga la Geoarqueología, una disciplina científica relativamente reciente, pero inexcusable de cara a conocer en qué contexto natural se desarrolla la ocupación y la transformación humana del territorio.