Papers by Eduardo Mayoral
Aeolian Research, 2013
Rhodoliths are spherical growths (coralline red algae) that contribute bioclasts to coastal dunes... more Rhodoliths are spherical growths (coralline red algae) that contribute bioclasts to coastal dunes in the Gulf of California (Mexico) and the Canary Islands (North Atlantic). Pleistocene dunes on Maio and São Nicolau islands in the Cape Verde archipelago were studied to quantify rhodolith contribution relative to other sources. Near Pilão Cão on Maio, a transverse dune at Lomba Greija covers 0.3 km 2 , exposing stoss slopes that dip 8°-10°NE and leeward slip faces that dip 28°-32°SW and SE. Point counts on thin-section samples show that basalt and other non-carbonate materials account for 5%, on average, whereas fine matrix and voided space (dissolved grains) account for 67%. Among remaining identifiable bioclasts (coralline red algae, mollusks, corals, foraminifera, and echinoderms), rhodolith grains with an average diameter of 0.5 mm account for 74%. Near Carriçal at Covoadinha de Chacina on the SE coast of São Nicolau, the stoss slope dips 8°SE for 70-80 m on narrow longitudinal dunes. Point counts on a thinsection sample taken 2.5 m above basement rock, reveal that basalt and other non-carbonate materials account for 10%, on average, whereas fine matrix and voided spaces account for 60%. Among identifiable bioclasts from the remainder (coralline red algae, mollusks, echinoderms, and bryozoa), rhodolith grains ranging in size from 0.5 to 1 mm account for 96%. Potential enrichment from coralline red algae may be overlooked in coastal dunes, because content normally is described as dominated by mollusk shells, the tests from abundant foraminifera, and/or ooids.
Exoskeletal abnormalities in middle Cambrian paradoxidid trilobites from Purujosa (Eastern Iberia... more Exoskeletal abnormalities in middle Cambrian paradoxidid trilobites from Purujosa (Eastern Iberian Chain, NE Spain) are herein analyzed for the first time. Two distinct types are reported. The first is represented by triangular or asymmetrical V-to W-shaped breaks on margins of isolated sclerites (cranidia, free cheeks and hypostomes). The second group is represented by shortened thoracic pleural spines in complete or nearly complete individuals. Possible causes of these injuries are discussed, but in some cases a single cause/effect explanation is not apparent. A new ichnotaxon, Mandibulichnus serratus nov. ichnogen., nov. ichnosp., is erected to refer to serrated breakage of the margins of isolated trilobite sclerites produced by active predation or scavenging. •
Developments in Sedimentology, 2012
Ichnofabric analysis was conducted in Miocene sediments from Lepe (Huelva, SW Spain) based on int... more Ichnofabric analysis was conducted in Miocene sediments from Lepe (Huelva, SW Spain) based on integrative
outcrop and core research, to improve interpretations of depositional and paleoenvironmental conditions, with
special attention to sequence stratigraphy. Seven intervalswere differentiated in outcrops based on stratigraphic
and ichnological features, consisting of two ichnofabrics: Ophiomorpha-Thalassinoides-Spongeliomorpha
ichnofabric characterizes intervals 1, 2, 6, 7 and 8, while Palaeophycus-Planolites-Phycosiphon ichnofabric characterizes
intervals 3, 4 and 5. Fourteen ichnofabrics were differentiated in the core, mainly in view of lithological
features, including ferruginous material, grain size, mottled background, ichnotaxa, and Bioturbation Index. A
comparison between outcrop and core ichnofabrics through the upper 13.5 m, corresponding to the uppermost
Tortonian-lowermost Messinian interval, revealed certain similarities as well as some differences. A continuous
and relatively slow siliciclastic deposition with punctual variations in the sedimentation rate can be interpreted
that, associated with favorable paleoenvironmental parameters such as aerobic conditions and nutrient availability,
evidence that a well-developed and diverse macroinvertebrate trace maker community existed at that time.
Softgrounds are dominant, but occasionally loosegrounds and even firmgrounds could develop. The ichnofabric
distribution shows long-range patterns in outcrop and core, and short-range patterns exclusively in core. Longrange
patterns reflect the last phases of a transgressive systemtract, with a “maximumflooding zone” at the end,
and then a highstand normal regression. High-frequency, short-range, repetitive patterns in ichnofabrics from
core, mainly between ichnofabrics 6/8 to 9 from lower to upper part of the pattern, can be linked to “local
flooding surfaces”, subdividing the “maximumflooding zone” into parasequences. Our results reveals the usefulness
of the integrative ichnofabric analysis, including outcrop and core materials, in sedimentary basin analysis,
assessing paleoenvironmental conditions and improving sequence stratigraphy characterization.
Coral-dwelling pyrgomatid barnacles (subfamily Ceratoconchinae) were widely dispersed throughout ... more Coral-dwelling pyrgomatid barnacles (subfamily Ceratoconchinae) were widely dispersed throughout the Paratethys and Mediterranean seas as well as the Atlantic Ocean during the Neogene, but today are limited to the Western Atlantic. Herein, the paleobiogeographic origin and dispersal of the genus Ceratoconcha is studied based on a combination of field, taxonomic, and literature studies. The first confirmed appearances of Ceratoconcha occur in lower Miocene strata (Burdigalian) with two closely related species on both sides of the Atlantic in western France and Florida. Fossils from the Miocene of Lanzarote in the Canary Islands and Pleisto-cene of Maio in the Cape Verde islands extend the known geographical and temporal range of the Ceratoconcha barnacles in the eastern Atlantic. During the Neogene, dispersal of marine taxa was a two-way process due to tec-tonic changes both influencing oceanic circulation and appearance and disappearance of oceanic islands. During the early Miocene, gyre formation was weak and the Atlantic Ocean mid-latitudes were warmer than today. This resulted in increased hurricane activity and the expansion of hermatypic coral hosts farther north in the North Atlantic. Normal ocean circulation transported barnacle larvae from east to west, but currents generated by hurricanes may have transported them in the opposite direction towards the margins of the northeastern Atlantic. Islands in between abetted barnacle contact and dispersal. The temporal range for Ceratoconcha is extended considerably in the eastern Atlantic from the early Pliocene to the Pleistocene. The hermatypic host corals of Ceratoconcha suffered a severe decline in the eastern Atlantic and the Mediterranean after the Miocene. Corals were present during the Pliocene and Pleistocene in the Cape Verde Islands. This suggests that the southernmost oceanic islands acted as a tropical refuge for host corals and their likely barnacle symbionts.
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Geological Journal, 2013
The classical lower-middle Cambrian boundary is approximately equivalent with the boundary of the... more The classical lower-middle Cambrian boundary is approximately equivalent with the boundary of the Cambrian Series 2 and 3, which is now in the process of definition by the International Subcommission on Cambrian Stratigraphy. Currently, there are two oryctocephalid trilobite species first appearance data (FAD) that are suggested as possible markers of this level: Ovatoryctocara granulata Tchernysheva, 1962 and Oryctocephalus indicus (Reed, 1910), respectively. Until now neither of these two species has been recorded in the Mediterranean subprovince or Baltica. As a result, in these regions a level potentially correlating with either the FAD of Ovatoryctocara granulata or Oryctocephalus indicus has to be located using the available bio-, isotope-, and event-stratigraphy data.
Treballs del Museu de Geologia de Barcelona, 2008
SANTOS, A. & MAYORAL, E. Bivalve palaeoecology from Upper Miocene of Cacela (SE Portugal).
The use of rocky palaeoshore bioerosion analysis in the study of palaeontological and geological ... more The use of rocky palaeoshore bioerosion analysis in the study of palaeontological and geological questions is beginning to bear fruit. Five southern Iberian Neogene rocky shores have been analysed and their bioerosion structures have been identified. The observed ichnodiversity is rather low; eleven ichnospecies were identified. These include bioerosion structures produced by polychaete annelids (Caulostrepsis, Maeandropolydora), clionaid sponges (Entobia), echi-noids (Circolites), and endolithic bivalves (Gastrochaenolites). The different ichnoassemblages present in Miocene rocky shores in both Portuguese and Spanish sectors correspond to the Entobia ichnofacies. Comparison with the northeastern counterparts of these shores has also been carried out. The study of southern Iberian Miocene rocky shores made it possible to correlate them with the regional tectonic evolution and the main Neogene transgressive events affecting the region.
mirage El Evento Valdemiedes en Murero (noreste de España) y la caracterización del límite Cámbri... more mirage El Evento Valdemiedes en Murero (noreste de España) y la caracterización del límite Cámbrico Inferior - Medio en la región Mediterránea. SeDiCI. Iniciar sesión. ...
The classical lower-middle Cambrian boundary is approximately equivalent with the boundary of the... more The classical lower-middle Cambrian boundary is approximately equivalent with the boundary of the Cambrian Series 2 and 3, which is now in the process of definition by the International Subcommission on Cambrian Stratigraphy. Currently, there are two oryctocephalid trilobite species first appearance data (FAD) that are suggested as possible markers of this level: Ovatoryctocara granulata Tchernysheva, 1962 and Oryctocephalus indicus (Reed, 1910), respectively. Until now neither of these two species has been recorded in the Mediterranean subprovince or Baltica. As a result, in these regions a level potentially correlating with either the FAD of Ovatoryctocara granulata or Oryctocephalus indicus has to be located using the available bio-, isotope-, and event-stratigraphy data.
A multidisciplinary study from a number of drilled cores in the Guadalquivir estuary has made pos... more A multidisciplinary study from a number of drilled cores in the Guadalquivir estuary has made possible to identify as many as three extreme wave events and their facies in the 4th millennium BP (A: ~4000 cal yr BP, B: ~3550 cal yr BP, and C: ~3150 cal yr BP). These events, which caused strong erosion in the Guadalquivir sandy barrier and in the neighboring aeolian systems of El Abalario, brought about significant paleogeographical changes that may have affected human settlements established in the area during the Neolithic and Copper Age periods and during the Middle Bronze Age. The three events can be spatially correlated and their facies differentiated from more proximal to more distal from the coastline. The most proximal facies is characterized by a massive accumulation of shells, a sandy or sandy–muddy matrix, an erosive base, a highly diverse mixture of species (marine and estuarine), and lithoclasts. The most distal facies presents a muddy–sandy matrix, dominance of estuarine fauna, shell accumulation , presence of terrestrial species, mudpebbles, pebbles in a clayey matrix, and bioturbation. The evidence presented will further advance scientific knowledge about the impact of extreme wave events on coastal areas in SW Iberia and NW Africa.
Revista Espanola de Paleontologia
Se realiza un estudio taxonómico de la niacroflora del Plioceno (post-Zancliense) del área de Lep... more Se realiza un estudio taxonómico de la niacroflora del Plioceno (post-Zancliense) del área de Lepe (Cuenca del Guadalquivir, Huelva). Los fósiles vegetales se han encontrado en iin nivel arcilloso que se depositó en un ambiente estuarino junto a bivalvos. artrópodos e icnofósiles. Se han identificado 22 taxones, pertenecientes a las divisiones Coniferophyta y Magnoliophyta. El análisis de las asociaciones registradas indica que la vegetación que existió en la zona fue un matorral de tipo esclerófilo en donde se incluían elementos de tipo mediterráneo, que se desarro116 gracias a unas condiciones climhticas subtropicales con tina estación seca prolongada. Las plantas ripícolas debieron habitar zonas pantanosas semejantes a las que existen hoy en día en el SE de los Estados Unidos. La flora estudiada presenta semejanzas con las que se desarrollaron durante el Mioceno en la región de Cataluña.
Revista Espanola de …, Jan 1, 2004
Ninety discoid structures of big size occurring on a bedding plane of Nemakit-Daldynian to Tommot... more Ninety discoid structures of big size occurring on a bedding plane of Nemakit-Daldynian to Tommotian sandstones (i.e. Corduban in the Spanish scale of Cambrian stages) from south-western Spain are described. Cross-cutting relationships between discoid structures and associated trace fossils, as well as evidence for penecontemporaneous deformation of sediment laminae below the discoids, permit to interprete these structures as impressions of ancient, soft-bodied marine organisms. Taphonomic, biometric, and morphological studies suggest that they are outer moulds of both sides, subumbrellar and exumbrellar, of ancient jellyfish of hydrozoan coelenterates, whose canals resemble the modern genus Aequorea. With diameters up to 88 cm, Cordubia was a giant by hydromedusae standards. Palaeoichnological, lithological and sedimentological features suggest an extremely shallow, marine environment, where these organisms stranded during a single event.
Lethaia
2008: Colonization by barnacles on fossil Clypeaster : an exceptional example of larval settlemen... more 2008: Colonization by barnacles on fossil Clypeaster : an exceptional example of larval settlement. Lethaia , Vol. 41, The presence of c . 1450 individuals of the balanid barnacle Balanus crenatus Bruguière encrusting the test of a clypeasteroid sea urchin from the Late Miocene of the Guadalquivir Basin (southwestern Spain) allows proposing a settlement pattern linked to the growth of the encrusting organism. The possible influence of dip angle was controlled by dividing the test into four concentric zones ranging from lowest margin to apex (0-15 ° , 15-30 ° , 30-50 ° and 0 ° ). Contour diagrams were prepared to identify areas of highest barnacle density as well as size categories distribution in relationship to the pitch of the sea urchin test. The orientation of balanid tests was recorded and plotted on rose diagrams from 0 ° to 180 ° . Four size categories of barnacles were distinguished:
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Papers by Eduardo Mayoral
outcrop and core research, to improve interpretations of depositional and paleoenvironmental conditions, with
special attention to sequence stratigraphy. Seven intervalswere differentiated in outcrops based on stratigraphic
and ichnological features, consisting of two ichnofabrics: Ophiomorpha-Thalassinoides-Spongeliomorpha
ichnofabric characterizes intervals 1, 2, 6, 7 and 8, while Palaeophycus-Planolites-Phycosiphon ichnofabric characterizes
intervals 3, 4 and 5. Fourteen ichnofabrics were differentiated in the core, mainly in view of lithological
features, including ferruginous material, grain size, mottled background, ichnotaxa, and Bioturbation Index. A
comparison between outcrop and core ichnofabrics through the upper 13.5 m, corresponding to the uppermost
Tortonian-lowermost Messinian interval, revealed certain similarities as well as some differences. A continuous
and relatively slow siliciclastic deposition with punctual variations in the sedimentation rate can be interpreted
that, associated with favorable paleoenvironmental parameters such as aerobic conditions and nutrient availability,
evidence that a well-developed and diverse macroinvertebrate trace maker community existed at that time.
Softgrounds are dominant, but occasionally loosegrounds and even firmgrounds could develop. The ichnofabric
distribution shows long-range patterns in outcrop and core, and short-range patterns exclusively in core. Longrange
patterns reflect the last phases of a transgressive systemtract, with a “maximumflooding zone” at the end,
and then a highstand normal regression. High-frequency, short-range, repetitive patterns in ichnofabrics from
core, mainly between ichnofabrics 6/8 to 9 from lower to upper part of the pattern, can be linked to “local
flooding surfaces”, subdividing the “maximumflooding zone” into parasequences. Our results reveals the usefulness
of the integrative ichnofabric analysis, including outcrop and core materials, in sedimentary basin analysis,
assessing paleoenvironmental conditions and improving sequence stratigraphy characterization.
outcrop and core research, to improve interpretations of depositional and paleoenvironmental conditions, with
special attention to sequence stratigraphy. Seven intervalswere differentiated in outcrops based on stratigraphic
and ichnological features, consisting of two ichnofabrics: Ophiomorpha-Thalassinoides-Spongeliomorpha
ichnofabric characterizes intervals 1, 2, 6, 7 and 8, while Palaeophycus-Planolites-Phycosiphon ichnofabric characterizes
intervals 3, 4 and 5. Fourteen ichnofabrics were differentiated in the core, mainly in view of lithological
features, including ferruginous material, grain size, mottled background, ichnotaxa, and Bioturbation Index. A
comparison between outcrop and core ichnofabrics through the upper 13.5 m, corresponding to the uppermost
Tortonian-lowermost Messinian interval, revealed certain similarities as well as some differences. A continuous
and relatively slow siliciclastic deposition with punctual variations in the sedimentation rate can be interpreted
that, associated with favorable paleoenvironmental parameters such as aerobic conditions and nutrient availability,
evidence that a well-developed and diverse macroinvertebrate trace maker community existed at that time.
Softgrounds are dominant, but occasionally loosegrounds and even firmgrounds could develop. The ichnofabric
distribution shows long-range patterns in outcrop and core, and short-range patterns exclusively in core. Longrange
patterns reflect the last phases of a transgressive systemtract, with a “maximumflooding zone” at the end,
and then a highstand normal regression. High-frequency, short-range, repetitive patterns in ichnofabrics from
core, mainly between ichnofabrics 6/8 to 9 from lower to upper part of the pattern, can be linked to “local
flooding surfaces”, subdividing the “maximumflooding zone” into parasequences. Our results reveals the usefulness
of the integrative ichnofabric analysis, including outcrop and core materials, in sedimentary basin analysis,
assessing paleoenvironmental conditions and improving sequence stratigraphy characterization.