Search results for "Alae"
showing 10 items of 351 documents
Bulk carbonate isotope stratigraphy from CRP-3 core (Victoria Land Basin, Antarctica): evidence for Eocene–Oligocene palaeoclimatic evolution
2005
Bulk carbonate isotope compositions and carbonate petrography from upper Eocene and lower Oligocene siliciclastic sediments of the CRP-3 sediment core (Victoria Land Basin, Antarctica) have been investigated with the aim of contributing to reconstruction of the Antarctic Cenozoic palaeoclimate. Most of the carbonate is calcite cement occurring as patches, nodules and horizons and consisting of equant and/or drusy sparry calcite, pervasive blocky calcite and rare poikilotopic calcite spar. 18O-depleted values (from −17 to −8 δ‰) of the CRP-3 carbonates suggest that the precipitating fluids were a mixing between marine and meteoric waters from melting glaciers. The δ18O record exhibits a numb…
Changements climatiques et océanographiques au cours du Campanien – approche couplée minéralogie et géochimie
2018
The origin of the Late Cretaceous (~100 – 65 Ma) global cooling is not yet well understood. The evolution of sea surface and bottom temperatures shows an acceleration of the cooling during the Campanian stage (~84 Ma). The main goal of this study was to explore the processes driving this cooling, focusing on Campanian sediments from the Tethyan, Boreal and Atlantic realms.The clay mineralogical assemblages of several (hemi)pelagic sites, selected along a S-N transect, from 5° to 45°N, reveal an increase in continental weathering during the Campanian, expressed by enhanced kaolinite inputs. The detrital input related to the uplift of new continental areas seems to evolve from south to north.…
Witnesses of the early Pliocene sea-level rise in the Manilva Basin (Málaga, S Spain)
2020
The Sierra de la Utrera, a relief in the Manilva Basin (Malaga, SW Spain), shows bored surfaces at different heights above present-day sea level, from 96 m to 287 m. Borings occur in the eastern, central, and western parts of the Canuto de la Utrera, a prominent gorge in the central southern part of the relief excavated in Mesozoic limestones, as well as on the western end of the Canuto Chico, a smaller canyon in the northern part. Pliocene marine deposits fossilized the bored surfaces. Bored boulders of the substrate are embedded in the Pliocene sediments. The traces Gastrochaenolites ispp., Entobia ispp., Caulostrepsis ispp., Circolites kotoucensis, and Ericichnus asgaardi have been ident…
Antiguos puertos e islas en el litoral andaluz: cartografía, toponimia e historia
2003
Se trata de recordar y agradecer las enseñanzas del Dr. Rosselló y aplicarlas a las costas andaluzas, de cuyas variadas formas llaman la atención los procesos de aterramiento de la parte atlántica, donde hay lugares cuya situación actual no responde a su topónimo (Isla Cristina, San Juan del Puerto...). A estudios anteriores, añadimos noticias históricas y trazados de mapas, que señalan una rápida evolución, referido principalmente a tres ámbitos. La desembocadura del Guadiana, que pasa en época histórica de barras arenosas e islas a zonas cultivadas y urbanizaciones de playas; el antiguo estuario del río Piedras, con puertos aún en el XIX, que sustenta hoy marismas, naranjales y cultivos d…
Microstructure of Triassic conodont Pseudofurnishius murcianus van den Boogaard: Functional implications
2020
Pseudofurnishius murcianus van den Boogaard is a Triassic conodont with a very characteristic morphology, a blade with a rostral platform heavily denticulated, that makes it easily distinguishable from other coeval species. It is a well-know taxon that has been the object of several palaeobiological works, focused on their apparatus reconstruction, ontogeny and, recently, their P 1 element function. In order to increase our palaeobiology knowledge of this taxon we undertook a histological analysis to corroborate the functional hypothesis established for this conodont. The histological study demonstrated the presence of different microstructural types, suggesting that they are functional ada…
SISALv2: a comprehensive speleothem isotope database with multiple age–depth models
2020
Characterizing the temporal uncertainty in palaeoclimate records is crucial for analysing past climate change, correlating climate events between records, assessing climate periodicities, identifying potential triggers and evaluating climate model simulations. The first global compilation of speleothem isotope records by the SISAL (Speleothem Isotope Synthesis and Analysis) working group showed that age model uncertainties are not systematically reported in the published literature, and these are only available for a limited number of records (ca. 15 %, n = 107/691). To improve the usefulness of the SISAL database, we have (i) improved the database’s spatio-temporal coverage and (ii) create…
A Roof Tile from 1678 Found in Calasparra (Murcia) as an Abiding Medium of Writing
2017
Analysis of a red clay roof tile which bears an heretofore unknown inscription of the late 'procesal' script style and humanistic characters along with the date 1678, marking its exact year of manufacture. This tile was found on the roof of an old barn structure in ruins, located on 'Horno de Calasparra' Street (Murcia), before its demolition. We will also point out some of the more significant aspects of the historic profession of tile making, which has all but disappeared. Se expone a continuación una teja de barro cocido en cuyo lomo se observa incisa una inédita frase, presentando una escritura de tipo procesal tardío, con caracteres ya humanísticos, y una fecha, 1678, la cual marca el …
Developments and contributions in the study of La Rioja dinosaur footprints (Spain)
2020
In this paper the study of dinosaur tracks of La Rioja, which began in 1970, is presented as an example of knowledge development, achievements, and events occurring around a paleontological resource having strong media impact. Fieldwork, research, and dissemination since the publication of the first scientific works have been accompanied by activities to protect sites and consider them as natural and cultural heritage. Finally it is shown how a paleontological resource has also led to the development of the tourist infrastructure in the area
Vulnerability of the North Water ecosystem to climate change
2021
High Arctic ecosystems and Indigenous livelihoods are tightly linked and exposed to climate change, yet assessing their sensitivity requires a long-term perspective. Here, we assess the vulnerability of the North Water polynya, a unique seaice ecosystem that sustains the world’s northernmost Inuit communities and several keystone Arctic species. We reconstruct mid-to-late Holocene changes in sea ice, marine primary production, and little auk colony dynamics through multi-proxy analysis of marine and lake sediment cores. Our results suggest a productive ecosystem by 4400–4200 cal yrs b2k coincident with the arrival of the first humans in Greenland. Climate forcing during the late Holocene, l…
Towards understanding the abundance of non-pollen palynomorphs : A comparison of fossil algae, algal pigments and sedaDNA from temperate lake sedimen…
2018
Given the increased interest in non-pollen palynomorphs (microscopic objects other than pollen identified from pollen slides) in palaeoecological studies, it is necessary to seek a deeper understanding of the reliability of these results. We combined quantitative information of algal pigments and sedimentary ancient DNA (sedaDNA) of phylotaxonomical resolution to validate the richness and abundance of fossil algae in the sediment of a small temperate lake. For the first time, fossil and sedaDNA algae data were combined in a composite data-set and used to reconstruct algae turnover rates over the last 14,500 years. This comparison serves as both an example of howfossil algae can be used to a…