scholarly journals Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms

2015 ◽  
Vol 112 (51) ◽  
pp. 15562-15567 ◽  
Author(s):  
Jocelyn Anne Sessa ◽  
Ekaterina Larina ◽  
Katja Knoll ◽  
Matthew Garb ◽  
J. Kirk Cochran ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Water Column ◽  
Oxygen Isotope ◽  
Benthic Foraminifera ◽  
Planktonic Foraminifera ◽  
Type Locality ◽  
Benthic Organisms ◽  
Isotopic Data ◽  
Excellent Opportunity ◽  
Upper Maastrichtian

Ammonites are among the best-known fossils of the Phanerozoic, yet their habitat is poorly understood. Three common ammonite families (Baculitidae, Scaphitidae, and Sphenodiscidae) co-occur with well-preserved planktonic and benthic organisms at the type locality of the upper Maastrichtian Owl Creek Formation, offering an excellent opportunity to constrain their depth habitats through isotopic comparisons among taxa. Based on sedimentary evidence and the micro- and macrofauna at this site, we infer that the 9-m-thick sequence was deposited at a paleodepth of 70–150 m. Taxa present throughout the sequence include a diverse assemblage of ammonites, bivalves, and gastropods, abundant benthic foraminifera, and rare planktonic foraminifera. No stratigraphic trends are observed in the isotopic data of any taxon, and thus all of the data from each taxon are considered as replicates. Oxygen isotope-based temperature estimates from the baculites and scaphites overlap with those of the benthos and are distinct from those of the plankton. In contrast, sphenodiscid temperature estimates span a range that includes estimates of the planktonic foraminifera and of the warmer half of the benthic values. These results suggest baculites and scaphites lived close to the seafloor, whereas sphenodiscids sometimes inhabited the upper water column and/or lived closer to shore. In fact, the rarity and poorer preservation of the sphenodiscids relative to the baculites and scaphites suggests that the sphenodiscid shells may have only reached the Owl Creek locality by drifting seaward after death.

scholarly journals Planktonic and benthic foraminiferal biostratigraphy of the Middle Eocene–Lower Miocene successions from the Sivas Basin (Central Anatolia, Turkey)

2016 ◽  
Vol 67 (1) ◽  
pp. 21-40 ◽  
Author(s):  
Aynur Hakyemez ◽  
Nazire Özgen-Erdem ◽  
Özgen Kangal
Keyword(s):  
Water Column ◽  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Central Anatolia ◽  
Successive Interval ◽  
Lower Miocene ◽  
Sivas Basin ◽  
Algal Reef ◽  
Foraminiferal Biostratigraphy

AbstractPlanktonic and benthic foraminifera are described from the Middle Eocene-Lower Miocene successions in the Sivas Basin, Central Anatolia. An integrated foraminiferal zonation provides new age assignments in terms of a great number of taxa for the studied sections. Four biostratigraphical intervals are first recorded based on the concurrent ranges of sporadically occurring but well preserved planktonic foraminiferal assemblages. The first interval characterized by the co-occurrences ofAcarinina bullbrooki, Truncorotaloides topilensisandTurborotalia cerroazulensisis referable to the E11 Zone of late Lutetian–early Bartonian. An assemblage yieldingParagloborotalia opimaaccompanied byGlobigerinella obesaforms a basis for the late Chattian O5 Zone. The successive interval corresponds to the late Chattian O6 Zone indicated by the presence ofGlobigerina ciperoensisandGlobigerinoides primordiusalong with the absence ofParagloborotalia opima. The early Aquitanian M1 Zone can be tentatively defined based mainly on the assemblage ofGlobigerina, Globigerinella, GloboturborotalitaandTenuitella. The biostratigraphical data obtained from the benthic foraminifera assign the studied sections to the SBZ 21–22, SBZ 23 and SBZ 24 ranging in age from Rupelian to Aquitanian. The SBZ 23 and 24 are well constrained biozones by the occurrences ofMiogypsinella complanataandMiogypsina gunteri, respectively, whereas the SBZ 21–22 defined by nummulitids and lepidocylinids in the Tethyan Shallow Benthic Zonation is characterized dominantly by peneroplids, soritids and miliolids in the studied sections. Benthic foraminiferal assemblages suggest different paleoenvironments covering lagoon, algal reef and shallow open marine whereas planktonic foraminifera provides evidence for relatively deep marine settings on the basis of assemblages characterized by a mixture of small-sized simple and more complex morphogroups indicative for intermediate depths of the water column.

Quantitative reconstruction of past climate mean states in the Atacama Desert using hydrogen and triple oxygen isotopes of gypsum hydration water

2020 ◽  
Author(s):  
Claudia Voigt ◽  
Daniel Herwartz ◽  
Michael Staubwasser
Keyword(s):  
Wind Speed ◽  
Isotopic Composition ◽  
Oxygen Isotope ◽  
Atacama Desert ◽  
Variable Degree ◽  
State Variables ◽  
Isotopic Data ◽  
Evaporation Model ◽  
Isotope Data ◽  
Mean State

<p>Gypsum crystals capture the isotopic composition (δ<sup>2</sup>H, δ<sup>17</sup>O, and δ<sup>18</sup>O) of ambient water in their structurally bonded water and may serve as a useful tool to reconstruct paleoclimate. Relative humidity, water temperature, wind speed, along with the isotopic composition of atmospheric vapor and inflowing water control, to a variable degree, the relative proportion of equilibrium and kinetic isotope fractionation during evaporation, and, thus, ultimately determine the d-excess and <sup>17</sup>O-excess of gypsum-bonded water. Here, we demonstrate that the respective best fit of these variables through measured gypsum-bonded water isotope data using the classic Craig-Gordon evaporation model provides apparent absolute values for the fundamental climate mean state variables humidity and temperature and an empirical wind speed parameter of the geologic past.</p><p>In this proof-of-concept study, we sampled gypsum crystals within individual stratigraphic units of Pliocene lacustrine deposits from the Atacama Desert, extracted their structurally bonded water, and analyzed the hydrogen and triple oxygen isotope composition. The spread of measured isotope data within each sampled stratigraphic unit suggests variable degrees of evaporation between individual gypsum samples along a common evaporation trajectory. We used the Craig-Gordon evaporation model together with a Monte Carlo simulation to determine the limits of climate mean state variables that fit the measured isotopic data.</p><p>Our results demonstrate that primary isotope signatures of marine and continental source waters are preserved in structurally bonded gypsum waters. The data coherently suggest a slightly warmer (18-35°C), less windy and much more humid (50-75%) climate for the Pliocene Atacama, which is consistent with marine records and global circulation climate models that agree on “permanent El Niño” conditions for the Pliocene in the equatorial East Pacific.</p><p>Under the assumption that mixing of different brines or multiple sources is insignificant - as would be evident from scattering of isotopic data below the evaporation trajectory in <sup>17</sup>O-excess over δ<sup>18</sup>O – the combined hydrogen and triple oxygen isotope analyses of gypsum-bonded water provides a powerful tool to quantify past mean states of humidity and temperature, and to estimate paleo-wind conditions.</p>

THE ABUNDANCE OF RECENT FORAMINIFERA IN SURFACE SEDIMENT OF AMBON BAY

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Suhartati M. Natsir
Keyword(s):  
Surface Sediment ◽  
Benthic Foraminifera ◽  
Sea Water ◽  
Planktonic Foraminifera ◽  
Sediment Characteristic ◽  
Abundance And Distribution

Foraminifera are generally live in sea water with various sizes. These organisms consist of planktonic and benthic foraminifera. Geological activity on plutonic and volcanic with vomiting magma is transpiring on, and then affects sedimentation and foraminiferal abundance of Ambon Bay. The study was determined to study the abundance and distribution of foraminifera based on the sediment characteristic of Ambon Bay. Sample collected in 2007 of Ambon Bay showed that only 29 samples of 50 samples containing foraminifera. The collected sediments have 86 species of foraminifera, consisting 61 species of benthic foraminifera and 25 species of planktonic foraminifera. The dominant benthic foraminifera in the surface sediment of Ambon bay were Amphistegina lessonii, Ammoniabeccarii,Elphidium craticulatum,Operculina ammonoides and Quinqueloculina parkery. The planktonic foraminifera that were frequently collected from the bay were Globorotalia tumida, Globoquadrina pseudofoliata, Globigerinoides pseudofoliata, Globigerinoides cyclostomus dan Pulleniatina finalis. Generally, the species dwelled as abundant on substrate sand, whereas the areas within substrate mud have no foraminifera lie on them. Keywords: Foraminifera, Abundance, Sediment, Ambon Bay

1.  Toxicity of Fresh and Weathered Sunken Heavy Fuel Oil to the Early Life Stages of Rainbow Trout (Oncorhynchus mykiss) in Simulated Spawning Shoal Environments

2016 ◽  
Author(s):  
Julie Adams
Keyword(s):  
Rainbow Trout ◽  
Water Column ◽  
Aquatic Organisms ◽  
Fuel Oil ◽  
South American ◽  
Benthic Organisms ◽  
Heavy Fuel Oil ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Direct Exposure ◽  
Insight Into

Because the density of heavy fuel oil (HFO) is equal to or greater than that of freshwater, it behaves differently than lighter oils that float. Heavy fuel oil can sink to the bottom or be suspended in the water column and affect aquatic organisms that are not typically exposed to floating oils. Most research on oil spill technologies thus far examines the direct exposure of rainbow trout to floating or submerged oil droplets; there is little knowledge of the impacts of non‐floating heavy fuel oil on the water column and benthic organisms exposed to oil that accumulates in sediments. The toxicity of sunken HFO 6303 and Medium South American (MESA; reference) crude oil, as well as the effects of weathering on toxicity to embryos of rainbow trout were assessed using increasing concentrations of oil on gravel substrate in continuous‐flow desorption columns. Toxicity was assessed by measurement of the rates of mortality and growth, and the prevalence of blue sac disease, a hallmark sign of oil toxicity. The lower median lethal concentration for HFO compared to MESA indicated that HFO is more toxic. Interestingly, the LC50 values for fresh and weathered for both oils were similar, indicating little change in toxicity when the oil weathers naturally. Repetition of this experiment and analysis of PAH content in each treatment will provide more insight into the environmental and health risks associated with sunken heavy fuel oil.   

Planktonic Foraminifera from the Type Locality of the Esna Shale in Egypt

1964 ◽  
Vol 10 (3) ◽  
pp. 375 ◽  
Author(s):  
Rushdi Said ◽  
Hassan Sabry
Keyword(s):  
Planktonic Foraminifera ◽  
Type Locality

scholarly journals Characterization and significance of dedolomite in Wadi Nisah, central Saudi Arabia

GeoArabia ◽  
2007 ◽  
Vol 12 (3) ◽  
pp. 15-30 ◽  
Author(s):  
Dave L. Cantrell ◽  
Abdullah Al-Khammash ◽  
Peter D. Jenden
Keyword(s):  
Saudi Arabia ◽  
Isotopic Composition ◽  
Oxygen Isotope ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Reservoir Quality ◽  
Meteoric Diagenesis ◽  
Different Types ◽  
Lower Oxygen ◽  
Lower Carbon

ABSTRACT Two different types of calcified dolomite, or dedolomite, occur as stratiform and non-stratiform bodies within the Jurassic (Kimmeridgian) upper Jubaila Formation in the Wadi Nisah area of central Saudi Arabia. In the stratigraphically-equivalent subsurface Arab-D reservoir in eastern Saudi Arabia, two types of dolomite, stratiform and non-stratiform, occur which appear to be similar in architecture to the dedolomites examined in this study. However, Wadi Nisah dedolomites exhibit systematic changes in texture and isotopic composition from their precursor dolomites. Non-stratiform dedolomite contains lower oxygen isotope (average δ18O = -10.99‰) and much lower carbon isotope (average δ13C = -7.51‰) values and is much more coarsely crystalline than typical subsurface Arab-D non-stratiform dolomite; in contrast, Wadi Nisah stratiform dedolomite contains similar oxygen isotope values (δ18O = -2.89‰) and only slightly lower carbon isotopes (δ13C = 0.98‰) relative to subsurface Arab-D stratiform dolomites. We suggest that non-stratiform dolomite was more susceptible to late meteoric diagenesis than the horizontally bedded stratiform dolomite intervals. Such differences in character highlight the importance of structural and diagenetic architecture in determining later, post-dolomitization diagenesis and ultimately final reservoir quality.

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