scholarly journals Disentangling shallow-water bulk carbonate carbon isotope archives with evidence for multi-stage diagenesis: An in-depth component-specific petrographic and geochemical study from Oman (mid-Cretaceous)

2017 ◽  
Vol 3 (2) ◽  
pp. 233-257 ◽  
Author(s):  
Stefan Huck ◽  
Stephan Wohlwend ◽  
Rute Coimbra ◽  
Nicolas Christ ◽  
Helmut Weissert
Keyword(s):  
Shallow Water ◽  
Carbon Isotope ◽  
Carbonate Carbon ◽  
Multi Stage ◽  
Geochemical Study

scholarly journals Finite-Volume Multi-Stage Scheme for Advection-Diffusion Modeling in Shallow Water Flows

2011 ◽  
Vol 27 (3) ◽  
pp. 415-430 ◽  
Author(s):  
W.-D. Guo ◽  
J.-S. Lai ◽  
G.-F. Lin ◽  
F.-Z. Lee ◽  
Y.-C. Tan
Keyword(s):  
Shallow Water ◽  
Finite Volume ◽  
Coupled System ◽  
High Order Accuracy ◽  
Suspended Sediment Transport ◽  
Reconstruction Method ◽  
Advection Diffusion Equation ◽  
Advection Diffusion ◽  
Multi Stage ◽  
Stage Scheme

ABSTRACTThis paper adopts the finite-volume multi-stage (FMUSTA) scheme to the two-dimensional coupled system combining the shallow water equations and the advection-diffusion equation. For the convection part, the numerical flux is estimated by adopting the FMUSTA scheme, where high order accuracy is achieved by the data reconstruction using the monotonic upstream schemes for conservation laws method. For the diffusion part, the evaluations of first-order derivatives are solved via the method of Jacobian transformation. The hydrostatic reconstruction method is employed for treatment of source terms. The overall accuracy of resulting scheme is second-order both in time and space. In addition, the scheme is non-oscillatory and conserves the pollutant mass during the transport process. For scheme validation, six advection and diffusion transport tests are simulated. The influences of the grid spacing and limiters on the numerical performance are also discussed. Furthermore, the scheme is employed in the simulation of suspended sediment transport in natural-irregular river topography. From the satisfactory agreements between the simulated results and the field measured data, it is demonstrated that the proposed FMUSTA scheme is practically suitable for hydraulic engineering applications.

scholarly journals Seawater-buffered diagenesis, destruction of carbon isotope excursions, and the composition of DIC in Neoproterozoic oceans

2019 ◽  
Vol 116 (38) ◽  
pp. 18874-18879 ◽  
Author(s):  
Paul F. Hoffman ◽  
Kelsey G. Lamothe
Keyword(s):  
Shallow Water ◽  
Carbon Isotope ◽  
Deep Sea ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Open Ocean ◽  
Carbonate Sediments ◽  
Carbonate Platforms ◽  
Mg Isotopes ◽  
Marine Platform

Carbonate sediments of nonglacial Cryogenian (659 to 649 Ma) and early Ediacaran (635 to 590 Ma) age exhibit large positive and negative δ13Ccarb excursions in a shallow-water marine platform in northern Namibia. The same excursions are recorded in fringing deep-sea fans and in carbonate platforms on other paleocontinents. However, coeval carbonates in the upper foreslope of the Namibian platform, and to a lesser extent in the outermost platform, have relatively uniform δ13Ccarb compositions compatible with dissolved inorganic carbon (DIC) in the modern ocean. We attribute the uniform values to fluid-buffered diagenesis that occurred where seawater invaded the sediment in response to geothermal porewater convection. This attribution, which is testable with paired Ca and Mg isotopes, implies that large δ13Ccarb excursions observed in Neoproterozoic platforms, while sedimentary in origin, do not reflect the composition of ancient open-ocean DIC.

Latest Devonian to earliest Carboniferous conodont and carbon isotope stratigraphy of a shallow-water sequence in South China

2015 ◽  
Vol 51 (6) ◽  
pp. 915-935 ◽  
Author(s):  
Wenkun Qie ◽  
Xiang-Dong Wang ◽  
Xionghua Zhang ◽  
Wenting Ji ◽  
Ethan L. Grossman ◽  
...  
Keyword(s):  
Shallow Water ◽  
Carbon Isotope ◽  
South China ◽  
Carbon Isotope Stratigraphy ◽  
Isotope Stratigraphy

scholarly journals Sequence stratigraphy, chemostratigraphy and facies analysis of Cambrian Series 2 – Series 3 boundary strata in northwestern Scotland

2016 ◽  
Vol 155 (4) ◽  
pp. 865-877 ◽  
Author(s):  
LUKE E. FAGGETTER ◽  
PAUL B. WIGNALL ◽  
SARA B. PRUSS ◽  
YADONG SUN ◽  
ROBERT J. RAINE ◽  
...  
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Carbon Isotope ◽  
Sea Level Changes ◽  
Carbon Isotopic ◽  
Carbonate Carbon ◽  
Carbon Isotope Excursion ◽  
Isotope Record ◽  
Laurentian Margin ◽  
Sequence Boundaries

AbstractGlobally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary andOlenellusbiostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to record regressive–transgressive events that produced amalgamated sequence boundaries and ravinement/flooding surfaces overlain by conglomerates of reworked intraclasts. The ROECE has been linked with redlichiid and olenellid trilobite extinctions, but in NW Scotland,Olenellusis found after the negative peak of the carbon isotope excursion but before sequence boundary formation.

scholarly journals Stratigraphic significance of carbon isotope variations in the shallow-marine Seis/Siusi Permian–Triassic boundary section (Southern Alps, Italy)

Fossil Record ◽  
2009 ◽  
Vol 12 (2) ◽  
pp. 197-205 ◽  
Author(s):  
S. H. Kraus ◽  
S. Siegert ◽  
W. Mette ◽  
U. Struck ◽  
C. Korte
Keyword(s):  
Carbon Isotope ◽  
Southern Alps ◽  
Late Permian ◽  
Current Event ◽  
Triassic Boundary ◽  
Shallow Marine ◽  
Carbonate Carbon ◽  
Biostratigraphic Correlation ◽  
Positive Peak ◽  
Permian Triassic Boundary

Carbonate carbon-isotope values from the Permian–Triassic (P–T) boundary section at Seis/Siusi (Southern Alps, Italy) show a trend similar to that in numerous other P–T boundary sections worldwide. Values decrease from 3.2‰ (V-PDB) in the upper <i>Bellerophon</i> Limestone Formation (Late Permian) to a minimum of –1.7‰ in the lower Mazzin Member. This minimum may represent the P–T boundary. The overall declining carbon-isotope trend is interrupted by a ca. 1‰ positive excursion in the higher Tesero Oolite Horizon. This positive peak is located at a higher lithostratigraphic level than a comparable peak in the adjacent Pufels section, which suggests that the Tesero Oolite Horizon in the Seis section is stratigraphically slightly older than in the Pufels section, and this is also suggested by palaeomagnetic correlation. It is therefore concluded that the base of the Tesero Oolite Horizon does not reflect a synchronous "current event" but is slightly diachronous, a result that was previously shown by biostratigraphic correlation. Nevertheless, this suggestion should be verified by further detailed litho-, magneto- and chemostratigraphic analysis of other P–T sections in the Southern Alps. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.200900007" target="_blank">10.1002/mmng.200900007</a>

scholarly journals Carbon cycle history through the Middle Jurassic (Aalenian – Bathonian) of the Mecsek Mountains, Southern Hungary

2018 ◽  
Vol 69 (2) ◽  
pp. 117-127
Author(s):  
Gregory D. Price ◽  
István Főzy ◽  
András Galácz
Keyword(s):  
Carbon Isotope ◽  
Middle Jurassic ◽  
Age Determination ◽  
Upper Jurassic ◽  
Stratigraphic Correlation ◽  
Carbonate Carbon ◽  
Run Off ◽  
Carbon Isotope Excursion ◽  
Isotope Stratigraphy

AbstractA carbonate carbon isotope curve from the Aalenian–Bathonian interval is presented from the Óbánya valley, of the Mecsek Mountains, Hungary. This interval is certainly less well constrained and studied than other Jurassic time slices. The Óbánya valley lies in the eastern part of the Mecsek Mountains, between Óbánya and Kisújbánya and provides exposures of an Aalenian to Lower Cretaceous sequence. It is not strongly affected by tectonics, as compared to other sections of eastern Mecsek of the same age. In parts, a rich fossil assemblage has been collected, with Bathonian ammonites being especially valuable at this locality. The pelagic Middle Jurassic is represented by the Komló Calcareous Marl Formation and thin-bedded limestones of the Óbánya Limestone Formation. These are overlain by Upper Jurassic siliceous limestones and radiolarites of the Fonyászó Limestone Formation. Our new data indicate a series of carbon isotope anomalies within the late Aalenian and early-middle Bajocian. In particular, analysis of the Komló Calcareous Marl Formation reveals a negative carbon isotope excursion followed by positive values that occurs near the base of the section (across the Aalenian–Bajocian boundary). The origin of this carbon-isotope anomaly is interpreted to lie in significant changes to carbon fluxes potentially stemming from reduced run off, lowering the fertility of surface waters which in turn leads to lessened primary production and a negative δ13C shift. These data are comparable with carbonate carbon isotope records from other Tethyan margin sediments. Our integrated biostratigraphy and carbon isotope stratigraphy enable us to improve stratigraphic correlation and age determination of the examined strata. Therefore, this study of the Komló Calcareous Marl Formation confirms that the existing carbon isotope curves serve as a global standard for Aalenian–Bathonian δ13C variation.

scholarly journals Chemo- and biostratigraphy of the Gaojiashan section (northern Yangtze platform, South China): a new Pc-C boundary section

Fossil Record ◽  
2015 ◽  
Vol 18 (2) ◽  
pp. 105-117 ◽  
Author(s):  
A. Gamper ◽  
U. Struck ◽  
F. Ohnemueller ◽  
C. Heubeck ◽  
S. Hohl
Keyword(s):  
Shallow Water ◽  
South China ◽  
Shaanxi Province ◽  
Cambrian Explosion ◽  
Local Perturbation ◽  
Data Set ◽  
Carbonate Carbon ◽  
Dengying Formation ◽  
Isotope Record ◽  
Ediacaran Fauna

Abstract. The widespread, terminal Ediacaran Dengying Formation (~ 551–~ 542 Ma) of South China hosts one of the most prominent negative carbonate carbon isotope excursions in Earth's history and thus bears on the correlation of the Precambrian–Cambrian boundary worldwide. The dominantly carbonate strata of the Dengying Formation are largely studied for their unique preservation of its terminal Ediacaran fauna but their geochemical context is poorly known. This study presents the first high-resolution stable isotope record (δ13C, δ18O) of calcareous siliciclastic shallow-water deposits of the Gaojiashan section (Shaanxi Province). The section includes (in ascending order) the Algal Dolomite Member, the Gaojiashan Member and the Beiwan Member of the Dengying Formation. Our data record a major δ13Ccarb negative excursion to −6 ‰ in the uppermost Gaojiashan Member which is comparable in shape and magnitude to the global Precambrian–Cambrian boundary negative δ13C excursion. Our data set is consistent with a "shallow-water anoxia" scenario which is thought to contribute to the "Cambrian explosion". The stratigraphic occurrence of Cloudina and a large negative δ13C excursion suggest that the Precambrian–Cambrian boundary is located near the top of the Gaojiashan Member and, consequently, that overlying carbonates and dolomites of the Beiwan Member are of earliest Cambrian age. Thus the Gaojiashan section may represent a new shallow-water section spanning the Precambrian–Cambrian boundary. Although bio- and chemostratigraphic data support this novel interpretation, we cannot exclude the possibility that the key excursions may represent a local perturbation indicating a restricted-basin environment.

Sign in / Sign up

Export Citation Format

Share Document