scholarly journals Global synchronous changes in the carbon isotopic composition of carbonate sediments unrelated to changes in the global carbon cycle

2008 ◽  
Vol 105 (37) ◽  
pp. 13741-13745 ◽  
Author(s):  
P. K. Swart
Keyword(s):  
Carbon Cycle ◽  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
Global Carbon Cycle ◽  
Carbonate Sediments ◽  
Carbon Isotopic ◽  
Global Carbon

The stable carbon isotopic composition of organic material in platform derived sediments: implications for reconstructing the global carbon cycle

Sedimentology ◽  
2011 ◽  
Vol 59 (1) ◽  
pp. 319-335 ◽  
Author(s):  
AMANDA M. OEHLERT ◽  
KATHRYN A. LAMB-WOZNIAK ◽  
QUINN B. DEVLIN ◽  
GRETA J. MACKENZIE ◽  
JOHN J. G. REIJMER ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Isotopic Composition ◽  
Organic Material ◽  
Carbon Isotopic Composition ◽  
Global Carbon Cycle ◽  
Stable Carbon ◽  
Carbon Isotopic ◽  
Global Carbon

Secular variation in the global carbon cycle during the Mesozoic: a new composite carbonate δ13C reference curve calibrated to GTS2020

2020 ◽  
Author(s):  
Ian Jarvis
Keyword(s):  
Time Series ◽  
Carbon Cycle ◽  
Carbon Isotope ◽  
Global Carbon Cycle ◽  
Published Data ◽  
Time Interval ◽  
Reference Curve ◽  
Carbonate Sediments ◽  
Lower Amplitude ◽  
Global Carbon

<p>A new δ<sup>13</sup>C reference curve for the Mesozoic is presented. This has been constructed using in excess of 10,000 published analyses of bulk carbonate sediments extracted from published literature.  Available data from sections world-wide were compiled for each stage and the stratigraphic trends visually compared.  Data sets used to construct the composite reference curve were those offering patterns that are consistent with other sections and offer the highest stratigraphic resolution (close sample spacing), constrained by biostratigraphic first appearance (FAD) and last appearance datum (LAD) levels, magnetostratigraphy, radiometric dates and cyclostratigraphy.  Preference was given to time series that showed the least scatter.  Pelagic carbonates proved most suitable for these purposes but data from hemipelagic and shallow-water carbonate sections were included where necessary. </p><p>Age calibration was achieved using stage boundary ages, biostratigraphic FAD and LAD datums levels, and chron boundary ages derived from the new GTS2020 timescale.  Where possible, data from multiple authors and/or multiple stratigraphic sections were age-calibrated and interleaved to generate composite profiles for each time interval.  Data from individual stages were spliced together with offsets being avoided wherever possible; minor offsets in values were corrected where necessary to generate a continuous smooth time series.  The uneven geographical spread of published data and suitable lithofacies has resulted in source information being derived from different regions for different time intervals.  For example, the Early – Middle Triassic curve is constructed from eastern Paleotethys sections (South China), the Jurassic and Early Cretaceous curves principally from Tethyan areas of Europe and North Africa (Morocco, Portugal, southern France, Switzerland, northern Italy), and the Late Cretaceous curve from the Boreal Sea of northern Europe (England, Denmark).  The global significance of the resulting curves requires further testing.</p><p>The stratigraphic positions and recalibrated ages of positive and negative δ<sup>13</sup>C excursions that define carbon isotope events (CIEs) are presented.  These reflect major perturbation in the global carbon cycle.  Changes in the production and burial of organic matter on land and in the oceans, plus the balance between carbonate versus organic carbon deposition, are the principal mechanisms driving the observed long-term stratigraphic trends and short-term excursions.  These are linked to palaeogeographic and palaeoceanographic change, with climate and sea-level fluctuations driven by orbital forcing, tectonics, and volcanic events.  The emplacement of large igneous plateaus (LIPs) and associated volcanism likely played a major role in driving many of the palaeoenvironmental perturbations reflected in the carbon isotope stratigraphy. </p><p>The most prominent CIEs characterise the Early Triassic with amplitudes exceeding 5‰ δ<sup>13</sup>C<sub>carb </sub>(VPDB), with other notable excursions in the mid-Carnian, mid-Norian and Rhaetian.  The Toarcian negative CIEs are the stand-out feature of the Jurassic, but multiple lower amplitude CIEs occur throughout, notably in the Hettangian, Bajocian Callovian and Oxfordian.  The most prominent Cretaceous CIEs in the Valanginian, Aptian and at the Cenomanian/Turonian boundary are linked to Oceanic Anoxic Events.</p>

Authigenic Carbonate and the History of the Global Carbon Cycle

Science ◽  
2013 ◽  
Vol 339 (6119) ◽  
pp. 540-543 ◽  
Author(s):  
Daniel P. Schrag ◽  
John. A. Higgins ◽  
Francis A. Macdonald ◽  
David T. Johnston
Keyword(s):  
Carbon Cycle ◽  
Carbon Isotope ◽  
Atmospheric Oxygen ◽  
Carbon Isotopic Composition ◽  
Minor Component ◽  
Authigenic Carbonate ◽  
Carbon Isotopic ◽  
History Of ◽  
A Minor ◽  
Global Carbon

We present a framework for interpreting the carbon isotopic composition of sedimentary rocks, which in turn requires a fundamental reinterpretation of the carbon cycle and redox budgets over Earth's history. We propose that authigenic carbonate, produced in sediment pore fluids during early diagenesis, has played a major role in the carbon cycle in the past. This sink constitutes a minor component of the carbon isotope mass balance under the modern, high levels of atmospheric oxygen but was much larger in times of low atmospheric O2or widespread marine anoxia. Waxing and waning of a global authigenic carbonate sink helps to explain extreme carbon isotope variations in the Proterozoic, Paleozoic, and Triassic.

scholarly journals A high resolution record of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the glacial inception

2013 ◽  
Vol 9 (2) ◽  
pp. 2015-2057 ◽  
Author(s):  
R. Schneider ◽  
J. Schmitt ◽  
P. Köhler ◽  
F. Joos ◽  
H. Fischer
Keyword(s):  
Carbon Cycle ◽  
Isotopic Composition ◽  
Atmospheric Carbon Dioxide ◽  
Stable Carbon Isotope ◽  
Carbon Isotopic Composition ◽  
Ice Cores ◽  
Glacial Maximum ◽  
Stable Carbon ◽  
Isotopic Data ◽  
Carbon Isotopic

Abstract. The reconstruction of the stable carbon isotope evolution in atmospheric CO2 (δ13Catm), as archived in Antarctic ice cores, bears the potential to disentangle the contributions of the different carbon cycle fluxes causing past CO2 variations. Here we present a highly resolved record of δ13Catm before, during and after the Marine Isotope Stage 5.5 (155 000 to 105 000 yr BP). The record was derived with a well established sublimation method using ice from the EPICA Dome C (EDC) and the Talos Dome ice cores in East Antarctica. We find an 0.4‰ offset between the mean δ13Catm level in the Penultimate (~140 000 yr BP) and Last Glacial Maximum (~22 000 yr BP), which can be explained by either (i) changes in the isotopic composition or (ii) intensity of the carbon input fluxes to the combined ocean/atmosphere carbon reservoir or (iii) by long-term peat buildup. Our isotopic data suggest that the carbon cycle evolution along Termination II and the subsequent interglacial was controlled by essentially the same processes as during the last 24 000 yr, but with different phasing and magnitudes. Furthermore, a 5000 yr lag in the CO2 decline relative to EDC temperatures is confirmed during the glacial inception at the end of MIS 5.5 (120 000 yr BP). Based on our isotopic data this lag can be explained by terrestrial carbon release and carbonate compensation.

Evidence for a widespread carbon isotopic event associated with late Middle Ordovician sedimentological and faunal changes in Estonia

1999 ◽  
Vol 136 (1) ◽  
pp. 49-62 ◽  
Author(s):  
LEHO AINSAAR ◽  
TÕNU MEIDLA ◽  
TÕNU MARTMA
Keyword(s):  
Isotopic Composition ◽  
Sea Level ◽  
Thermohaline Circulation ◽  
Carbon Isotopic Composition ◽  
Shelf Area ◽  
Carbonate Sediments ◽  
Sea Level Changes ◽  
Middle Ordovician ◽  
Carbon Isotopic ◽  
The North

An episode of remarkable biotic, climatic, sea-level and facies changes took place during the late Viruan (Caradoc) epoch in the Baltoscandian area. We studied the carbon isotopic composition of carbonate sediments from this period. Data on the stable carbon isotopic composition of whole-rock carbonates from three south Estonian core sections, together with those on ostracode, distribution are presented. In two core sections, a positive δ13C shift of 2 ‰ was revealed in the upper part of the Keila Stage (mid-Caradoc). The comparison of isotope and ostracode data in the sections suggested the occurrence of a gap of late Keilan age in the marginal area of the basin equivalent to the North Estonian Confacies Belt. The beginning of the excursion approximately coincided with climatic and sea-level changes in the shallow shelf area. The peak of the late Keilan excursion preceded the biotic crises and maximum black shale accumulation in the Baltoscandian palaeobasin. An approximately synchronous carbon isotopic event has been reported from North America, referring to a possible global oceanographic event in the Caradoc epoch. Although the positive carbon isotopic excursion and related environmental events of the late Keilan age have some unique features, they show more similarities to the end-Ordovician and Silurian events, characterized by oceanic change from stratified state to thermohaline circulation state, than to warm anoxic events related to eustatic sea-level rise.

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