Carbon isotope geochemistry and palaeontology of Neoproterozoic to early Cambrian siliciclastic successions in the East European Platform, Poland

1997 ◽  
Vol 134 (1) ◽  
pp. 1-16 ◽  
Author(s):  
HARALD STRAUSS ◽  
GONZALO VIDAL ◽  
MAŁGORZATA MOCZYDŁOWSKA ◽  
JOLANTA PACZEŚNA
Keyword(s):  
Organic Carbon ◽  
East European Platform ◽  
Carbonate Platform ◽  
Isotope Geochemistry ◽  
Carbon Isotopic Composition ◽  
Early Cambrian ◽  
East European ◽  
Carbon Isotopic ◽  
Radiation Extinction ◽  
Extinction Events

A well-preserved stratigraphic record of the organic carbon isotopic composition across the Precambrian–Cambrian transition has been obtained from a sequence of entirely detrital rocks underlying the Lublin Slope, East European Platform, Poland. The observed δ13C pattern for organic carbon is comparable to isotope data determined for coeval carbonate platform sequences elsewhere. These results underline the truly global nature of these secular variations within the carbon cycle during the terminal Proterozoic and early Cambrian, largely independent of host lithology and facies. The direct combination of micropalaeontological and geochemical results from sedimentary organic matter allows a detailed interpretation of the isotope record as probably caused by secular changes in the net balance of burial and erosion rates of repositories of organic carbon. Furthermore, these variations appear to be directly correlatable with changes in the diversity and abundance of the biota and radiation/extinction events.

Nd isotope composition of the Ediacaran and earliest Cambrian phosphorite nodules and Fe sulphide from the East European Platform

2020 ◽  
Vol 157 (12) ◽  
pp. 2081-2088
Author(s):  
Sergey B Felitsyn ◽  
Eugeny S. Bogomolov
Keyword(s):  
East European Platform ◽  
Isotope Composition ◽  
Water Reservoir ◽  
Secular Change ◽  
Early Cambrian ◽  
Iron Sulphide ◽  
Nd Isotope ◽  
East European ◽  
Moscow Syneclise ◽  
Nd Isotope Composition

AbstractAn enhanced concentration of phosphorus has been found at the stratigraphic level of the disappearance of Ediacaran taxa in two areas, the Cis-Dniester region and the Moscow syneclise, on the East European Platform (EEP). The isotope composition of neodymium was determined in Fe sulphide and phosphorite in the same beds. Measured εNd(t) values in diagenetic phosphate nodules are similar to those in iron sulphide from the same layer. During the Ediacaran − Early Cambrian, accumulation of radiogenic Nd in the epeiric basins on the EEP increased progressively from −17.9 and −19.4 in pyrite from the sequence bottom to −7.9 and −8.5 in the Early Cambrian pyrite of the central part of the EEP. The Ediacaran phosphate nodules show εNd(t) ranging from −12.9 to −15.0, while that in the Early Cambrian nodules is typically c. −9.0. These data indicate the secular change in Nd isotope composition of the water reservoir on the EEP from Ediacaran to Cambrian.

scholarly journals Spatial distribution and sources of organic carbon in the surface sediment of the Bosten Lake, China

2015 ◽  
Vol 12 (16) ◽  
pp. 13793-13817 ◽  
Author(s):  
Z. T. Yu ◽  
X. J. Wang ◽  
E. L. Zhang ◽  
C. Y. Zhao ◽  
H. Y. Lan
Keyword(s):  
Spatial Distribution ◽  
Organic Carbon ◽  
Energy Levels ◽  
Carbon Isotopic Composition ◽  
Bosten Lake ◽  
Carbon Isotopic ◽  
Complex Processes ◽  
High Kinetic Energy ◽  
Carbon Reservoir ◽  
Kaidu River

Abstract. Lake sediment is an important carbon reservoir. However, little is known on the dynamics and sources of sediment organic carbon in the Bosten Lake. We collected 13 surface (0–2 cm) sediment samples in the Bosten Lake and analyzed total organic carbon (TOC), total nitrogen (TN), stable carbon isotopic composition in TOC (δ13Corg) and grain size. We found a large spatial variability in TOC content (1.8–4.4 %) and δ13Corg value (−26.77 to −23.98 ‰). Using a three end member mixing model with measured TOC : TN ratio and δ13Corg, we estimated that 54–90 % of TOC was from autochthonous sources. Higher TOC content (> 3.7 %) was found in the east and central-north sections and near the mouth of the Kaidu River, which was attributable to allochthonous, autochthonous plus allochthonous, and autochthonous sources, respectively. The lowest TOC content was found in the mid-west section, which might be a result of high kinetic energy levels. Our study indicated that the spatial distribution of sediment TOC in the Bosten Lake was influenced by multiple and complex processes.

scholarly journals Carbon Isotopic Composition of Deep Carbon Gases in an Ombrogenous Peatland, Northwestern Ontario, Canada

Radiocarbon ◽  
1993 ◽  
Vol 35 (2) ◽  
pp. 271-276 ◽  
Author(s):  
Ramon Aravena ◽  
B. G. Warner ◽  
D. J. Charman ◽  
L. R. Belyea ◽  
S. P. Mathur ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Radiocarbon Dating ◽  
Carbon Isotopic Composition ◽  
Downward Movement ◽  
Terrestrial Biosphere ◽  
Carbon Isotopic ◽  
Northwestern Ontario ◽  
Global Carbon ◽  
Isotope Analyses ◽  
Carbon Gases

Radiocarbon dating and carbon isotope analyses of deep peat and gases in a small ombrogenous peatland in northwestern Ontario reveals the presence of old gases at depth that are 1000–2000 yr younger than the enclosing peat. We suggest that the most likely explanation to account for this age discrepancy is the downward movement by advection of younger dissolved organic carbon for use by fermentation and methanogens bacteria. This study identifies a potentially large supply of old carbon gases in peatlands that should be considered in global carbon models of the terrestrial biosphere.

scholarly journals Isotopic and chromatographic fingerprinting of the sources of dissolved organic carbon in a shallow coastal aquifer

2020 ◽  
Vol 24 (4) ◽  
pp. 2167-2178 ◽  
Author(s):  
Karina T. Meredith ◽  
Andy Baker ◽  
Martin S. Andersen ◽  
Denis M. O'Carroll ◽  
Helen Rutlidge ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Coastal Aquifer ◽  
Carbon Isotopic Composition ◽  
Median Concentration ◽  
Carbon Isotopic ◽  
Groundwater Samples ◽  
Doc Concentration ◽  
Geochemical Analyses ◽  
Terrestrial Subsurface

Abstract. The terrestrial subsurface is the largest source of freshwater globally. The organic carbon contained within it and processes controlling its concentration remain largely unknown. The global median concentration of dissolved organic carbon (DOC) in groundwater is low compared to surface waters, suggesting significant processing in the subsurface. Yet the processes that remove this DOC in groundwater are not fully understood. The purpose of this study was to investigate the different sources and processes influencing DOC in a shallow anoxic coastal aquifer. Uniquely, this study combines liquid chromatography organic carbon detection with organic (δ13CDOC) carbon isotope geochemical analyses to fingerprint the various DOC sources that influence the concentration, carbon isotopic composition, and character with respect to distance from surface water sources, depth below surface, and inferred groundwater residence time (using 3H activities) in groundwater. It was found that the average groundwater DOC concentration was 5 times higher (5 mg L−1) than the global median concentration and that the concentration doubled with depth at our site, but the chromatographic character did not change significantly. The anoxic saturated conditions of the aquifer limited the rate of organic matter processing, leading to enhanced preservation and storage of the DOC sources from peats and palaeosols contained within the aquifer. All groundwater samples were more aromatic for their molecular weight in comparison to other lakes, rivers and surface marine samples studied. The destabilization or changes in hydrology, whether by anthropogenic or natural processes, could lead to the flux of up to 10 times more unreacted organic carbon from this coastal aquifer compared to deeper inland aquifers.

scholarly journals Carbon isotopic composition of branched tetraether membrane lipids in soils suggest a rapid turnover and a heterotrophic life style of their source organism(s)

2010 ◽  
Vol 7 (9) ◽  
pp. 2959-2973 ◽  
Author(s):  
J. W. H. Weijers ◽  
G. L. B. Wiesenberg ◽  
R. Bol ◽  
E. C. Hopmans ◽  
R. D. Pancost
Keyword(s):  
Organic Carbon ◽  
Isotopic Composition ◽  
Life Style ◽  
Membrane Lipids ◽  
Carbon Isotopic Composition ◽  
Turnover Time ◽  
Arable Soils ◽  
Higher Plant ◽  
Δ13c Values ◽  
Carbon Isotopic

Abstract. Branched Glycerol Dialkyl Glycerol Tetraethers (GDGTs) are membrane spanning lipids synthesised by as yet unknown bacteria that thrive in soils and peat. In order to obtain more information on their ecological niche, the stable carbon isotopic composition of branched GDGT-derived alkanes, obtained upon ether bond cleavage, has been determined in a peat and various soils, i.e. forest, grassland and cropland, covered by various vegetation types, i.e., C3- vs. C4-plant type. These δ13C values are compared with those of bulk organic matter and higher plant derived n-alkanes from the same soils. With average δ13C values of −28‰, branched GDGTs in C3 soils are only slightly depleted (ca. 1‰) relative to bulk organic carbon and on average 8.5‰ enriched relative to plant wax-derived long-chain n-alkanes ( nC29–nC33). In an Australian soil dominantly covered with C4 type vegetation, the branched GDGTs have a δ13C value of −18‰, clearly higher than observed in soils with C3 type vegetation. As with C3 vegetated soils, branched GDGT δ13C values are slightly depleted (1‰) relative to bulk organic carbon and enriched (ca. 5‰) relative to n-alkanes in this soil. The δ13C values of branched GDGT lipids being similar to bulk organic carbon and their co-variation with those of bulk organic carbon and plant waxes, suggest a heterotrophic life style and assimilation of relatively heavy and likely labile substrates for the as yet unknown soil bacteria that synthesise the branched GDGT lipids. However, a chemoautotrophic lifestyle, i.e. consuming respired CO2, could not be fully excluded based on these data alone. Based on a natural labelling experiment of a C3/C4 crop change introduced on one of the soils 23 years before sampling and based on a free-air CO2 enrichment experiment with labelled CO2 on another soil, a turnover time of ca. 18 years has been estimated for branched GDGTs in these arable soils.

Lower Cambrian acritarchs from northern Spain: the Precambrian-Cambrian boundary and biostratigraphic implications

1992 ◽  
Vol 129 (4) ◽  
pp. 421-436 ◽  
Author(s):  
Teodoro Palacios ◽  
Gonzalo Vidal
Keyword(s):  
Lower Cambrian ◽  
East European Platform ◽  
Early Cambrian ◽  
Eastern Siberia ◽  
Western North America ◽  
Northern Spain ◽  
East European ◽  
Cantabrian Region ◽  
Biostratigraphic Correlation ◽  
Cambrian Trilobite

AbstractAcritarchs are reported from basal Cambrian rock units inthe Cantabrian region of northern Spain that are known to contain archaeocyathan and trilobite faunas. Biostratigraphic correlation of the Iberian sequences with other regions has been hampered by the strong provincialism of these faunas. However, this report of evidently cosmopolitan acritarch taxaestablishes the time equivalence of early Cambrian trilobite faunas from Iberia, Baltoscandia and the East European Platform (EEP). Our data suggest that the detrital deposition of the Lower Cambrian Herreria Formation embraces at least three (and possibly four) Lower Cambrian acritarch zones previously identified in the EEP, eastern Siberia, Baltoscandia, Scotland, Greenland, Svalbard and western North America. The early Cambrian transgression in northern Spain was probably initiated in Talsy times (Schmidtiellus mickwitzi trilobite Zone in Baltoscandia and the EEP), in part corresponding to the Dokidocyathus regularis archaeocyathian Zone of the Middle Tommotian in Siberia.

Sign in / Sign up

Export Citation Format

Share Document