Difference between revisions of "RECENT PUBLICATIONS ON FORAMINIFERA 2012 (3)"

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{{Recent Publications on Foraminifera Navigation}}<font size="2">
 
{{Recent Publications on Foraminifera Navigation}}<font size="2">
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==THE ECOLOGY AND BIOGEOGRAPHY OF ''Discospirina tenuissima'' IN THE ATLANTIC AND INDIAN OCEANS==
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[[Image:Deep-Sea_Research_II_front.gif‎|left|80px|]]<font size="2">
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The large (≥1 cm diameter) miliolid foraminifera ''Discospirina tenuissima'' (Carpenter and Jeffries, 1870) is common at four sites (NW, NE, SW, SE), located on either side of the Mid-Atlantic Ridge to the north (54°N) and south (49°N) of the Charlie-Gibbs Fracture Zone. The white discoidal tests of this epifaunal species were visible in video surveys of flat and gently (10°) sloping, sediment-covered areas of seafloor (replicate 500-m-long transects, 1000 m<sup>2</sup> surface area) obtained using the Remote Operated Vehicle ''Isis''. Considerable variation was also evident between individual transects (0–2.25 ind m−2). The tests displayed no consistent dispersion pattern; both significantly random and clumped patterns were observed, in some cases within a single site. ...... They were particularly common at the SE site, where one or two abandoned rings indicated that some tests had moved distances of several centimetres across the seafloor. Most previous records of ''D. tenuissima'' are from well-oxygenated sites in the NE Atlantic. We provide the first records from the Indian Ocean. Here, this species occurs at bathyal depths in the northwest (1980 m) and northeast (938 m) Arabian Sea, where bottom-water oxygen concentrations are depressed.
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<font size="2">([http://www.sciencedirect.com/science/article/pii/S0967064512000781 ABSTRACT])
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----Gooday, A.J., Alt, C.H.S., Jones, D.O.B., Shale, D., Marsden, K., Brasier, M.D., in press. [http://www.sciencedirect.com/science/article/pii/S0967064512000781 The Ecology and Biogeography of ''Discospirina tenuissima'' (Foraminifera) in the Atlantic and Indian Oceans]. Deep Sea Research II, doi:10.1016/j.dsr2.2012.05.001
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==EARLY STALL OF WEST ANTARCTIC ICE SHEET ADVANCE ON THE EASTERN ROSS SEA MIDDLE SHELF==
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[[Image:PPP_front.gif‎|left|80px|]]<font size="2">
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Marine geological and geophysical data suggest that the West Antarctic Ice Sheet (WAIS) deposited three thick seismically-resolvable units in the eastern Ross Sea since the Last Glacial Maximum (LGM) but the chronology of these grounding events is debated. Existing ice-retreat chronologies for the eastern Ross Sea are considered suspect because nearly all have been developed using radiocarbon dating of acid-insoluble organics (AIO) from bulk sediment. We used a new strategy to isolate in situ forams from diamict sediment deposited at the middle-shelf grounding-zone wedge (GZW) — a subaqueous ice-marginal landform previously interpreted to represent deposition during the third grounding event since the LGM advance to the shelf edge. Here we present a synthesis of our new radiocarbon dates of foram tests and AIO with previously published radiocarbon dates. ......
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<font size="2">([http://www.sciencedirect.com/science/article/pii/S0031018211004330 ABSTRACT])
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----Bart, P.J., Cone, A.N., 2012. [http://www.sciencedirect.com/science/article/pii/S0031018211004330 Early stall of West Antarctic Ice Sheet advance on the eastern Ross Sea middle shelf followed by retreat at 27,500 <sup>14</sup>C yr BP]. Palaeogeography, Palaeoclimatology, Palaeoecology 335-336, 52-60.
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==MAGNITUDE AND TIMING OF EQUATORIAL ATLANTIC SURFACE WARMING DURING THE LAST GLACIAL BIPOLAR OSCILLATIONS==
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[[Image:Climate_of_the_Past_front.jpg‎|left|80px|]]<font size="2">
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We present core top and down core sample analyses of Mg/Ca in tests of planktonic foraminifer ''Globigerinoides ruber'' (variety pink) from the eastern Tropical-Equatorial Atlantic. Multivariate analysis of the core top data shows that Mg/Ca varies by 8 ± 2% and 1 ± 0.9% per unit sea surface temperature (SST) (°C) and salinity (psu) changes, respectively, indicating that temperature exerts the most dominant control on planktonic foraminiferal Mg/Ca variation. A centennially resolved record of Mg/Ca-based SST estimates from the Eastern Equatorial Atlantic (EEA) exhibits a close correlation between episodes of equatorial surface water warming, the onset of massive melt-water inputs into the North Atlantic (Heinrich events H3–H6), and rapid drop of air temperature over Greenland, indicating that the Eastern Equatorial Atlantic responded very sensitively to millennial-scale bipolar oscillations of the last glacial and marine isotope stage 3. ...... Our study emphasizes that changes in wind fields and wind-induced low latitude zonal surface currents were crucial in shaping the spatial heterogeneity and duration of Equatorial Atlantic surface water warmth.
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<font size="2">([http://www.clim-past-discuss.net/8/1737/2012/ ABSTRACT])
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----Weldeab, S., 2012. [http://www.clim-past-discuss.net/8/1737/2012/ Magnitude and timing of Equatorial Atlantic surface warming during the last glacial bipolar oscillations]. Climate of the Past Discussion 8, 1737-1762.
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==SST FOR LEFT-COILING ''Neogloboquadrina'' POPULATIONS IN THE WESTERN MOST MEDITERRANEAN IN PLEISTOCENE-PLIOCENE==
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[[Image:Geobios_cover.gif‎|left|80px|]]<font size="2">
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Using the modern analog methodology applied to planktonic foraminifers, we analyze the relation between the frequency of the coiling type in ''Neogloboquadrina'' populations and the sea-surface temperatures (SST) during the middle Pleistocene and the Pleistocene-Pliocene transition in the Alboran Sea (westernmost Mediterranean), close to the Atlantic connection. The results reveal that the present-day positive correlation between the two variables (r = 0.649) is maintained even with a higher coefficient (r = 0.783) in the middle Pleistocene but falls slightly (r = 0.517) in the Pleistocene-Pliocene transition due mainly to a dispersal of the temperatures for the samples bearing predominantly left-coiling ''Neogloboquadrina''. The temperature used as a reference for the coiling change resulted 5-6 °C above its North Atlantic present-day reciprocal, but these thermal differences could be caused by ...... these results in combination with those derived from the isotopic analyses (δ<sup>18</sup>O) in ''G. bulloides'' tests, suggest that during the Pliocene-Pleistocene transition two different populations of left-coiling ''Neogloboquadrina'' could have existed with different environmental requirements: one, derived from late Miocene-Pliocene (i.e., left-coiling ''N. acostaensis'' group), and another being the ancestor of the modern ''N. pachyderma'' (left-coiling). ......
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<font size="2">([http://www.sciencedirect.com/science/article/pii/S0016699512000162 ABSTRACT])
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----Serrano, F., Guerra-Merchán, A., in press. [http://www.sciencedirect.com/science/article/pii/S0016699512000162 Sea-surface temperature for left-coiling ''Neogloboquadrina populations'' inhabiting the westernmost Mediterranean in the middle Pleistocene and the Pleistocene-Pliocene transition]. Geobios, doi:10.1016/j.geobios.2011.04.003
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==LATE MIOCENE PALAEOGEOGRAPHIC EVOLUTION OF THE ATLANTIC - MEDITERRANEAN SEAWAY==
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[[Image:Geobios_cover.gif‎|left|80px|]]<font size="2">
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The marine stratigraphic record of the Granada Basin (central Betic Cordillera, Spain) is composed of three Late Miocene genetic units deposited in different sea-level contexts (from base to top): Unit I (sea-level rise), Unit II (high sea-level), and Unit III (low sea-level). The latter mainly consists of evaporites precipitated in a shallow-basin setting. Biostratigraphic analyses based on planktonic foraminifera and calcareous nannoplankton indicate four late Tortonian bioevents (PF1-CN1, PF2, PF3, and PF4), which can be correlated with astronomically-dated events in other sections of the Mediterranean. ...... Comparisons with data from the other Betic basins indicate that the evaporitic phase of the Granada Basin (7.37-7.24 Ma) is not synchronous with those from the Lorca Basin (7.80 Ma) and the Fortuna Basin (7.6 Ma). In the Bajo Segura Basin (easternmost Betic Cordillera), no evaporite deposition occurred during the late Tortonian. The evaporitic unit of the Granada Basin (central Betics) records the late Tortonian restriction of the Betic seaway (the marine connection between the Atlantic and Mediterranean). The diachrony in the restriction of the Betic seaway is related to differing tectonic movements in the central and eastern sectors of the Betic Cordillera.
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<font size="2">([http://www.sciencedirect.com/science/article/pii/S0016699512000332 ABSTRACT])
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----Corbí, H., Lancis, C., Harcía-García, F., Pina, J.-A., Soria, J.M, Tent-Manclús, J.E., Viseras, C., in press. [http://www.sciencedirect.com/science/article/pii/S0016699512000332 Updating the marine biostratigraphy of the Granada Basin (central Betic Cordillera). Insight for the Late Miocene palaeogeographic evolution of the Atlantic - Mediterranean seaway]. Geobios, doi:10.1016/j.geobios.2011.10.006
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==''Praeorbitolina''/''Palorbitolinoides'' ASSOCIATION: AN APTIAN BIOSTRATIGRAPHIC KEY-INTERVAL IN THE NEO-TETHYS==
 
==''Praeorbitolina''/''Palorbitolinoides'' ASSOCIATION: AN APTIAN BIOSTRATIGRAPHIC KEY-INTERVAL IN THE NEO-TETHYS==

Latest revision as of 16:02, 31 July 2012