Search results for "Foraminifera"
showing 10 items of 144 documents
Suborbital climate variability during Marine Isotopic Stage 5 in the central Mediterranean basin: evidence from calcareous plankton record
2006
Abstract New faunal and floral records from Ocean Drilling Project Hole 963A, resolved at ∼80-year spacing, provide evidence of suborbital scale climate variability in the central Mediterranean Sea throughout Marine Isotope Stage (MIS) 5. Cold events in the central Mediterranean Sea, indicated by low abundances of warm species and high abundances of cold species, are also evident in a planktonic foraminifera paleoclimatic curve. They have been linked to NGRIP Greenland ice core “C” events and appear correlative with similar sub-millennial climate fluctuations identified in the North Atlantic region and in the Alboran Basin (Westernmost Mediterranean). Low-resolution benthic and planktonic O…
Palaeoenvironments and Quaternary foraminifera in the Elx coastal lagoon (Alicante, Spain)
2010
Abstract During the Quaternary, different palaeoenvironments characterised the Elx coastal lagoon (‘Albufera d'Elx’) located in the easternmost sector of the Betic Ranges (SE Spain). Micropalaeontological and sedimentological analysis of three drilled cores allowed characterization of different sedimentary environments, including alluvial, restricted lagoon, lagoon with marine connection, shoreface, foreshore, backshore, swamp, washover fan, and back-barrier flat. A model of the evolution of this region during Marine Isotope Stage (MIS) 7 is proposed, based on chronostratigraphic correlation between the cores. Up to six transgressive episodes can be recognised, mostly represented by calcare…
Evolucion paleoambiental desde el Holoceno temprano hasta la actualidad del marjal de Almenara (Mediterráneo occidental)
2018
The main aim of this study is to characterize the different stages in the palaeoenvironmental evolution of the Almenara marsh, Spain, from the early Holocene to the present day. This marsh is one of the most important in Castellón province. Five cores extracted from the marsh underwent sedimentological analysis, micropalaeontological study (foraminifera, ostracods and gastropods) and 14C dating. The results show that before the maximum transgression of the Mediterranean during the Marine Isotope Stage 1 (5500 cal yr. BP dating in the Almenara marsh), the area was occupied by a brackish marsh (prior to the 8.2 ka event). During the middle Holocene, the regional sea level rise and later stabi…
Surface hydrographic changes at the western flank of the sicily channel associated with the last sapropel
2021
Abstract In the eastern Mediterranean Sea, the early Holocene was characterized by major climatic and oceanographic changes that led to the formation of the last sapropel (S1) between 10.8 and 6.1 kyr cal. BP. These hydrographic changes might have altered the water exchange between the eastern and western Mediterranean sub-basins through the Strait of Sicily, but the existing evidences are inconclusive. In the present study we show new evidence from sediment core NDT-6-2016 located at the western flank of the Sicily channel, a key location to monitor the surface/intermediate water exchange between the two Mediterranean sub-basins. We perform paleo-hydrographic reconstructions based on plank…
Holocene climate variability of the Western Mediterranean: Surface water dynamics inferred from calcareous plankton assemblages
2020
A high-resolution study (centennial scale) has been performed on the calcareous plankton assemblage of the Holocene portion of the Ocean Drilling Program Site 976 (Alboran Sea) with the aim to identify the main changes in the surface water dynamic. The dataset also provided a seasonal foraminiferal sea surface water temperatures (SSTs), estimated using the modern analog technique SIMMAX 28, and it was compared with available geochemical and pollen data at the site. Three main climate shifts were identified as (1) the increase in abundance of Syracosphaera spp. and Turborotalita quinqueloba marks the early Holocene humid phase, during maximum summer insolation and enhanced river runoff. It i…
Environmental evolution and mid–late Holocene climate events in the Valencia lagoon (Mediterranean coast of Spain)
2016
Integration of geomorphological, stratigraphic, malacological, sedimentological and micropalaeontological techniques and14C dating allows us to characterise the processes and evolution of the coastal barrier–lagoon system of Valencia (Spain), from the middle Holocene to the historical epoch, as well as the responses to global climate events. Four stages are recognised. Phase 1: around 8240 ± 80 cal. yr BP, a brackish lagoon of moderate energy and in restricted environment was formed, with an energy peak that could correspond to the maximum Holocene marine transgression. Dating (8240 ± 80 cal. yr BP) carried out in peat corresponds to a cold cycle and low water levels in inland lakes of the …
Maximum flood area during MIS 1 in the Almenara marshland (Western Mediterranean): Benthic foraminifera and sedimentary record
2018
The sedimentological and micropaleontological analysis of three mechanical cores in the marshland of Almenara (Valencian Community, Spain) has allowed the reconstruction of the Holocene evolution of this wetland. The cold and dry 8.2-ka event might be represented in Almenara by a massive carbonate precipitation bed, upon which mid- and late-Holocene sediments were subsequently deposited. The direct influence of sea-level changes has been recorded in the two cores (S-4 and S-5) located near the marsh barrier, at 400–450 m from the current coastline. The maximum flood area during MIS 1 (last 11,600 years) is represented in these cores by sediments indicative of different littoral subenvironm…
The Albian (Vraconnian)-Cenomanian boundary at the western Tethyan margins (Central Tunisia and southeastern France).
2008
AbstractThrough the description and interpretation of the position of macro- and microfossils in several sections of the Albian-Cenomanian boundary in SE France and Central Tunisia, a comparison is made between the north and south margins of the Tethyan Ocean by using the occurrences of marker bioevents. For the planktonic foraminifera, the criterions applicable for the accurate determination of Thalmanninella globotruncanoides (Sigal) – the marker species for the base of the Cenomanian stage – are discussed. The species Th. globotruncanoides and the intermediate forms with its ancestor Th. caroni (Ion) are illustrated. For the ammonites, two subjects are new. Firstly, the species Stoliczka…
Impact of human activities on the central Mediterranean offshore: Evidence from Hg distribution in box-core sediments from the Ionian Sea
2008
The Palermo and Augusta urban/industrial areas (Sicily) are examples of contaminated coastal environments with a relatively high influx of unregulated industrial and domestic effluents. Three sediment box-cores were collected offshore of these urban/industrial areas in water depths of 60–150mduring two cruises (summers 2003/2004), dated by 210Pb and 137Cs, and analysed for total mercury concentration and total polycyclic aromatic hydrocarbon (PAH) concentration. Benthic foraminiferal assemblages were also examined (in terms of their distribution and morphology) to assess the potential use of benthic foraminifera as bioindicators of pollutant input and environmental change in these Mediterra…
Centennial- to millennial-scale climate oscillations in the Central-Eastern Mediterranean Sea between 20,000 and 70,000 years ago: Evidence from a hi…
2012
Abstract Here we present a high-resolution faunal, floral and geochemical (stable isotopes and trace elements) record from the sediments of Ocean Drilling Program Site 963 (central Mediterranean basin), which shows centennial/millennial-scale resemblance to the high-northern latitude rapid temperature fluctuations documented in the Greenland ice cores between 20 and 70 kyr BP. Oxygen and carbon isotopes, planktic foraminifera and calcareous nannofossil distributions suggest that Dansgaard–Oeschger (D/O) and Heinrich events (HE) are distinctly expressed in the Mediterranean climate record. Moreover, recurrent though subdued oscillations not previously identified in the Lateglacial Mediterran…