scholarly journals Palaeoenvironmental evolution from the early Holocene to the present of the Almenara marsh (western Mediterranean)

2019 ◽  
Vol 82 (4) ◽  
pp. 257 ◽  
Author(s):  
Ana M. Blázquez-Morilla ◽  
Ana Rodríguez-Pérez ◽  
Daniel Sanjuán-Lamata
Keyword(s):  
Western Mediterranean ◽  
Freshwater Marsh ◽  
Water Levels ◽  
Early Holocene ◽  
Agricultural Activity ◽  
14C Dating ◽  
Foraminiferal Assemblage ◽  
Entire Area ◽  
Middle Holocene ◽  
Benthic Foraminiferal Assemblage

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 stability caused an oligohaline/freshwater marsh with fluctuating water levels to form. This marsh occupied the entire area of today’s Almenara marsh at least between 7570 and 2780 cal yr BP. The results may indicate a phase of greater contribution of groundwater inputs (and rainfall/riverine discharge) during the middle Holocene as a response to a climatic phase characterized by higher humidity. Today, the marsh is filled with sediments from natural and anthropic processes related to the agricultural activity carried out throughout the area (except for the central part, which has been reclaimed as wetland). The water of the present-day marsh (like that prior to 8.2 ka event) is brackish, as is indicated by the benthic foraminiferal assemblage; this contrasts with the earlier oligohaline/freshwater marsh determined in the survey cores during the middle Holocene until the time of the Iberian culture.

scholarly journals New speleothem data from Molinos and Ejulve caves reveal Holocene hydrological variability in northeast Iberia

2017 ◽  
Vol 88 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Ana Moreno ◽  
Carlos Pérez-Mejías ◽  
Miguel Bartolomé ◽  
Carlos Sancho ◽  
Isabel Cacho ◽  
...  
Keyword(s):  
Water Availability ◽  
Marked Change ◽  
Western Mediterranean ◽  
Early Holocene ◽  
Spring Precipitation ◽  
The Holocene ◽  
Middle Holocene ◽  
Hydrological Variability ◽  
Iberian Range ◽  
Climatic Signal

AbstractNew speleothem records from northeastern Iberian caves provide data to explore the climatic patterns during the Holocene. We present δ13C and Mg/Ca from three speleothems from two different caves located in the Iberian Range allowing replication of the climatic signal for several millennia. Through the integration of those stalagmites covering since the Holocene onset to 2 ka, the early Holocene (11.7–8.5 ka) appears as the wettest interval. A marked change towards aridity is observed during the middle Holocene (8.5–4.8 ka) and an increase of humidity afterwards (4.8–2 ka). This three-part pattern, contrasting with other Iberian sequences, seems to be associated with the different role that seasonality has played in the response of different proxies (or records) to changes in water availability. Interpreting our speleothem records as changes in winter-spring precipitation along the Holocene allows reconciling previous data on hydrological variability from the western Mediterranean borderlands.

scholarly journals Morphologische Untersuchungen im nordöstlichen Matmata-Vorland (nördliche Djeffara, Südtunesien)

1975 ◽  
Vol 26 (1) ◽  
pp. 218-240 ◽  
Author(s):  
Karl-Ulrich Brosche ◽  
Hans-Georg Molle
Keyword(s):  
Climatic Conditions ◽  
The Other ◽  
Early Holocene ◽  
Distribution Area ◽  
River Systems ◽  
14C Dating ◽  
Entire Area ◽  
Fine Sediments ◽  
River Bed ◽  
14C Age

Abstract. Geomorphological investigations into the sequence of formation phases in the area of the two river-systems Oued Termamane — Oued Zigzaou and Oued en Negueb — Oued El Hallouf — Oued Oum Es Zessar in N. Djeffara in S. Tunisia permit us to distinguish above the recent river-bed, apart from youngest, anthropogenically caused deposits, a "younger accumulation" composed of fine sediments, a "main accumulation" consisting for the most part of coarse pebbles and remainders of at least 2 older, higher-lying levels which cannot be reliably correlated. The "main accumulation" is found in the entire area of the aforementioned Oueds, the „younger accumulation" on the other hand only in their middle and lower courses. The latter is missing in the main distribution area of the Matmata silts (primarily wind-deposited, later fluviatile remodelled sediments), in the mountains and on their edges. On the strength of the 14C-dating of 2 charcoal specimens (Hv 5566 and Hv 5400) the deposits of the „younger accumulation" may be placed in the period between 9000 — 7000 B.P. The dating of a calccrust from the top of the "main accumulation" showed a 14C-age of 21385 ± 235 B.P. (Hv 5402). Even taking into account the considerable possibilities of error in this dating, a Würm age may be assumed for the "main accumulation". The silts of Matmata overlie the "main accumulation" and come into consideration as supplier of material for the sediments of the "younger accumulation", accordingly the age of the silts may be assumed to be Würm to Early Holocene. Climatic conditions more humid than those today are indicated by a fossilized "Kalkbraunerde" in the Matmata silts, the occurence of calccrusts and a transport of pebbles at the time of the "main accumulation" reaching considerably further into the Matmata foreland than the pebble-transport of the recent river-beds.

The Upper Cretaceous foraminiferal record of IODP Site U1512 (Great Australian Bight, Indian Ocean)

2021 ◽  
Author(s):  
Erik Wolfgring ◽  
Michael A. Kaminski ◽  
Anna Waśkowska ◽  
Maria Rose Petrizzo ◽  
Eun Young Lee ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Ocean Circulation ◽  
Planktonic Foraminifera ◽  
Late Eocene ◽  
Foraminiferal Assemblage ◽  
Benthic Foraminiferal Assemblage ◽  
International Ocean Discovery Program ◽  
Foraminiferal Record ◽  
Great Australian Bight ◽  
Microfossil Assemblage

<p>Site U1512 was drilled during Expedition 369 of the International Ocean Discovery Program (IODP), which is located in the Great Australian Bight, southern Indian Ocean. It provides exceptional insights into the benthic foraminiferal biostratigraphy and paleoecology of a high southern latitude restricted marginal marine basin during the Late Cretaceous hot greenhouse climate and the rifting between Australia and Antarctica. The sedimentary sequence recovered at Site U1512 presents a rare record of a deep water agglutinated foraminifera (DWAF) community from the Southern High Latitudes. The Cretaceous record at Site U1512 covers the lower Turonian through Santonian (nannofossil zones UC8b to UC12/CC10b to CC16, <em>H. helvetica</em> to <em>Marginotruncana</em> spp. - <em>Planoheterohelix papula</em> - <em>Globotruncana linneana</em> planktonic foraminifera zones). Diverse benthic foraminiferal assemblages yield many new taxa that are yet to be described.</p><p>Agglutinated forms dominate the assemblage in most intervals. In lower to mid Turonian and Santonian strata, calcareous benthic as well as planktonic foraminifera are frequent. Abundant radiolaria are recovered from the mid Turonian, and they increase up-section and exceed 50% of the microfossil assemblage. We documented a diverse benthic foraminiferal assemblage consisting of 162 taxa (110 agglutinated and 52 calcareous). The most common taxa of the DWAF assemblage are tubular (i.e., <em>Kalamopsis grzybowskii,</em> <em>Bathysiphon</em> spp.) and planispiral forms (i.e., <em>Ammodiscus</em> spp., <em>Haplophragmoides</em> spp., <em>Buzasina</em> sp., <em>Labrospira</em> spp.).</p><p>The Turonian strata yield highly abundant <em>Bulbobaculites problematicus</em> and <em>Spiroplectammina navarroana</em>. The presence of the agglutinated foraminiferal marker taxa <em>Uvigerinammina jankoi</em> and <em>Bulbobaculites problematicus</em> provides a tie-point to the Tethyan DWAF biozonation of Geroch and Nowak (1984). The composition of foraminiferal assemblages and the increase in radiolaria abundance suggest unstable environmental conditions at Site U1512 during the early Turonian through Santonian. These characteristics refer to changes in bathymetry associated with changing ocean chemistry. Results of quantitative analyses of the benthic foraminiferal assemblages indicate a restricted paleoenvironmental regime, dictated by changes in paleobathymetry, unstable patterns in ocean circulation, and the discharge of a nearby river delta system.</p><p>References: Geroch, S., Nowak, K., 1984. Proposal of zonation for the Late Tithonian – late Eocene. based upon arenaceous Foraminifera from the Outer Carpathians, Poland, 225-239, In: Oertli, H.J. (Ed.), Benthos ´83; 2nd international 915 Symposium on Benthic Foraminifera, Pau (France) April 11-15, 1983, Elf Aquitaine, ESO REP and TOTAL CFP, Pau and Bordeaux.</p><p> </p>

Nummulites Fayumensis N. Sp. and Nummulites Tenuissimus N. Sp. from Munquar El-rayan, Fayum, Egypt

2018 ◽  
Vol 48 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Safia Al Menoufy ◽  
Mohamed Boukhary
Keyword(s):  
New Species ◽  
Foraminiferal Assemblage ◽  
Shallow Marine ◽  
Marine Facies ◽  
Benthic Foraminiferal Assemblage ◽  
Insight Into ◽  
Important Site

Abstract Nummulites fayumensis n. sp. and Nummulites tenuissimus n. sp. are described from the Munqar El-Rayan Section, Fayum, Egypt. Nummulites tenuissimus belongs to the N. partschi group, while N. fayumensis belongs to the N. gizehensis group, based on diameter and protoconch sizes, septal shape and granulations. Both new species are of Lutetian age, assigned to SBZ14/15, and encountered in shallow-marine facies. Wadi El-Rayan is an important site for vertebrate fossils in Egypt and the abundant larger benthic foraminiferal assemblage provides insight into paleoenvironmental parameters associated with the deposition of Eocene-age rock units of the Munqar El-Rayan Section.

scholarly journals Holocene climate variability in the North-Western Mediterranean Sea (Gulf of Lions)

2016 ◽  
Vol 12 (1) ◽  
pp. 91-101 ◽  
Author(s):  
B. Jalali ◽  
M.-A. Sicre ◽  
M.-A. Bassetti ◽  
N. Kallel
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Early Holocene ◽  
Inner Shelf ◽  
Catchment Basin ◽  
Rhône River ◽  
Gulf Of Lions ◽  
The North ◽  
Western Mediterranean Sea ◽  
Rhone River

Abstract. Sea surface temperatures (SSTs) and land-derived input time series were generated from the Gulf of Lions inner-shelf sediments (NW Mediterranean Sea) using alkenones and high-molecular-weight odd-carbon numbered n-alkanes (TERR-alkanes), respectively. The SST record depicts three main phases: a warm Early Holocene ( ∼  18 ± 0.4  °C) followed by a cooling of  ∼  3  °C between 7000 and 1000 BP, and rapid warming from  ∼  1850 AD onwards. Several superimposed multi-decadal to centennial-scale cold events of  ∼  1  °C amplitude were also identified. TERR-alkanes were quantified in the same sedimentary horizons to identify periods of high Rhone River discharge and compare them with regional flood reconstructions. Concentrations show a broad increase from the Early Holocene towards the present with a pronounced minimum around 2500 BP and large fluctuations during the Late Holocene. Comparison with Holocene flood activity reconstructions across the Alps region suggests that sediments of the inner shelf originate mainly from the Upper Rhone River catchment basin and that they are primarily delivered during positive North Atlantic Oscillation (NAO).

scholarly journals Radiocarbon Variations from Tasmanian Conifers: Results from Three Early Holocene Logs

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Mike Barbetti ◽  
Trevor Bird ◽  
George Dolezal ◽  
Gillian Taylor ◽  
Roger Francey ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Calibration Curve ◽  
The Other ◽  
Early Holocene ◽  
Conifer Species ◽  
Middle Holocene ◽  
Calibration Curves ◽  
Lagarostrobos Franklinii ◽  
Floodplain Sediments ◽  
Good Coverage

Dendrochronological studies are being carried out on two conifer species in the Stanley River area of western Tasmania. The chronology for Huon pine (Lagarostrobos franklinii), with living trees up to 1400 yr old, extends back to 571 bc. Living celery-top pine (Phyllocladus aspleniifolius) trees are up to 500 yr old. Apart from living or recently felled trees, sections have been taken from 350 subfossil logs preserved in floodplain sediments. They range in age from >38 ka to modern, with good coverage for the periods 9–3.5 ka and from 2.5 ka to the present. We report here on 14C measurements of decadal samples from three early Holocene logs, between 10 and 9 ka bp, providing short (ca. 300-yr) records of atmospheric 14C variations when plotted against ring numbers. The southern hemisphere data from Tasmania can be compared and wiggle-matched with published 14C calibration curves from German oak and pine. One set of measurements covers the period, ca. 9280–8990 cal bp, overlapping the link between the Hohenheim “Main 9” and middle Holocene master oak chronologies. The other sets of measurements from Tasmania coincide; they span the period, ca. 9840–9480 cal bp, overlapping the end of the German Preboreal pine and the beginning of the oak chronologies. Our measurements confirm that this part of the calibration curve is a gently sloping 14C-age plateau (ca. 8900–8700 bp, between 10,000 and 9500 cal bp), and suggest interhemispheric 14C differences close to zero.

Sign in / Sign up

Export Citation Format

Share Document