Interpreting carbon-isotope excursions: carbonates and organic matter

Kump, Lee R.; Arthur, Michael A.

doi:10.1016/s0009-2541(99)00086-8

Cited by 982 publications

(594 citation statements)

References 58 publications

Supporting

Mentioning

573

Contrasting

Unclassified

Order By: Relevance

“…where the δ 13 C are defined in the usual way relative to the PDB standard, δ 13 C Vol,PI is taken to be −5‰ (Kump and Arthur, 1999) and δ 13 C Cal,PI and δ 13 C OrgC,PI are calculated from the steady state, pre-industrial model results (Sect. 3.2.3) as sector burial-weighted means of 13 C contents in organic carbon and biogenic carbonate produced in each ocean sector.…”

Section: Rock Weathering Volcanism and River Inputmentioning

confidence: 99%

Presentation, calibration and validation of the low-order, DCESS Earth System Model (Version 1)

2008

View full text Add to dashboard Cite

Abstract.A new, low-order Earth System Model is described, calibrated and tested against Earth system data. The model features modules for the atmosphere, ocean, ocean sediment, land biosphere and lithosphere and has been designed to simulate global change on time scales of years to millions of years. The atmosphere module considers radiation balance, meridional transport of heat and water vapor between low-mid latitude and high latitude zones, heat and gas exchange with the ocean and sea ice and snow cover. Gases considered are carbon dioxide and methane for all three carbon isotopes, nitrous oxide and oxygen. The ocean module has 100 m vertical resolution, carbonate chemistry and prescribed circulation and mixing. Ocean biogeochemical tracers are phosphate, dissolved oxygen, dissolved inorganic carbon for all three carbon isotopes and alkalinity. Biogenic production of particulate organic matter in the ocean surface layer depends on phosphate availability but with lower efficiency in the high latitude zone, as determined by model fit to ocean data. The calcite to organic carbon rain ratio depends on surface layer temperature. The semi-analytical, ocean sediment module considers calcium carbonate dissolution and oxic and anoxic organic matter remineralisation. The sediment is composed of calcite, non-calcite mineral and reactive organic matter. Sediment porosity profiles are related to sediment composition and a bioturbated layer of 0.1 m thickness is assumed. A sediment segment is ascribed to each ocean layer and segment area stems from observed ocean depth distributions. Sediment burial is calculated from Correspondence to: G. Shaffer (gs@dcess.ku.dk) sedimentation velocities at the base of the bioturbated layer. Bioturbation rates and oxic and anoxic remineralisation rates depend on organic carbon rain rates and dissolved oxygen concentrations. The land biosphere module considers leaves, wood, litter and soil. Net primary production depends on atmospheric carbon dioxide concentration and remineralization rates in the litter and soil are related to mean atmospheric temperatures. Methane production is a small fraction of the soil remineralization. The lithosphere module considers outgassing, weathering of carbonate and silicate rocks and weathering of rocks containing old organic carbon and phosphorus. Weathering rates are related to mean atmospheric temperatures.A pre-industrial, steady state calibration to Earth system data is carried out. Ocean observations of temperature, carbon 14, phosphate, dissolved oxygen, dissolved inorganic carbon and alkalinity constrain air-sea exchange and ocean circulation, mixing and biogeochemical parameters. Observed calcite and organic carbon distributions and inventories in the ocean sediment help constrain sediment module parameters. Carbon isotopic data and carbonate vs. silicate weathering fractions are used to estimate initial lithosphere outgassing and rock weathering rates. Model performance is tested by simulating atmospheric greenhouse gas increases, global warming ...

show abstract

Section: Rock Weathering Volcanism and River Inputmentioning

confidence: 99%

Presentation, calibration and validation of the low-order, DCESS Earth System Model (Version 1)

2008

View full text Add to dashboard Cite

show abstract

“…isotope ͉ organics ͉ shallow-water platform V ariations in the stable carbon isotopic composition (␦ 13 C) of calcium carbonate sediments throughout geological time have been an invaluable aid in unraveling changes in the global carbon cycle (1,2). In addition, such variations in ␦ 13 C have provided information on the transfer of carbon between reservoirs during major geological events such as bolide impacts or catastrophic climate changes (3,4).…”

mentioning

confidence: 99%

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

Swart

2008

Proc. Natl. Acad. Sci. U.S.A.

191

119

View full text Add to dashboard Cite

The carbon isotopic (␦ 13 C) composition of bulk carbonate sediments deposited off the margins of four carbonate platforms/ramp systems (Bahamas, Maldives, Queensland Plateau, and Great Australian Bight) show synchronous changes over the past 0 to 10 million years. However, these variations are different from the established global pattern in the ␦ 13 C measured in the open oceans over the same time period. For example, from 10 Ma to the present, the ␦ 13 C of open oceanic carbonate has decreased, whereas platform margin sediments analyzed here show an increase. It is suggested that the ␦ 13 C patterns in the marginal platform deposits are produced through admixing of aragonite-rich sediments, which have relatively positive ␦ 13 C values, with pelagic materials, which have lower ␦ 13 C values. As the more isotopically positive shallowwater carbonate sediments are only produced when the platforms are flooded, there is a connection between changes in global sea level and the ␦ 13 C of sediments in marginal settings. These data indicate that globally synchronous changes in ␦ 13 C can take place that are completely unrelated to variations in the global carbon cycle. Fluctuations in the ␦ 13 C of carbonate sediments measured during previous geological periods may also be subject to similar processes, and global synchroniety of ␦ 13 C can no longer necessarily be considered an indicator that such changes are related to, or caused by, variations in the burial of organic carbon. Inferences regarding the interpretation of changes in the cycling of organic carbon derived from ␦ 13 C records should be reconsidered in light of the findings presented here.isotope ͉ organics ͉ shallow-water platform V ariations in the stable carbon isotopic composition (␦ 13 C) of calcium carbonate sediments throughout geological time have been an invaluable aid in unraveling changes in the global carbon cycle (1, 2). In addition, such variations in ␦ 13 C have provided information on the transfer of carbon between reservoirs during major geological events such as bolide impacts or catastrophic climate changes (3, 4). Generally speaking, increases in the ␦ 13 C of carbonates are considered indicative of increased burial and preservation of isotopically negative organic carbon, whereas decreases in the ␦ 13 C suggest transfer of carbon from the organic into the inorganic reservoir (5-7). Hence, variation in the ␦ 13 C of carbonate material should be a proxy for the amount of buried organic carbon. For example, the ␦ 13 C of the oceanic record has become increasingly more negative over the past 50 million years (Myr) (8, 9), suggesting that as much as 10 20 g of organic carbon have been transferred from the organic to the inorganic carbon reservoir (6).The most reliable archives of changes in the ␦ 13 C of the oceans over the past 100 Myr to 200 Myr are contained in the skeletons of planktic and benthic foraminifera (9, 10). Not only are these organisms relatively diagenetically stable, but the ␦ 13 C values can be corrected for any species-spe...

show abstract

“…In contrast to water depth indicators, almost nothing is known about the productivity of Paleozoic oceans and seas (e.g., Kump and Arthur, 1999;Saltzman, 2002) due to lack of 'good' proxy information relating primary seawater productivity to chemistry in pristine shells of brachiopods. Perhaps, the combination of δ 13 C and the micronutrient such as iron may open up a new venue for evaluating seawater productivity based on brachiopodbased iron similar to the established diatom model (e.g., Bruland et al, 2005;Fasham et al, 2006).…”

Section: Great Basin Seawaymentioning

confidence: 99%

“…Kump and Arthur, 1999;Parkinson et al, 2005). Two causes for the observed negative/positive shifts in stratigraphic δ 13 C carbonate values have been put forth, where 1) "…long-term secular shifts caused by changes in the fractional burial of organic carbon, and 2) transient shifts caused by abrupt changes of biological productivity in the surface photic zone…" (Holser, 1997, p. 173).…”

Section: Productivity-carbon Isotopesmentioning

confidence: 99%

“…Despite, the apparent direct relationship between δ 13 C values, organic matter burial and application to atmospheric CO 2 content from the geologic record (e.g., Kump and Arthur, 1999), this association between modern marine particulate organic matter and plankton and aqueous CO 2 have revealed inconsistent results (Pancost et al, 1997;Rau et al, 2001). In one instance the δ 13 C of diatoms is controlled by their growth rate (Pancost et al, 1997), which in turn may be limited by the micronutrient iron (Bruland et al, 2001).…”

Section: Productivity-carbon Isotopesmentioning

confidence: 99%

See 1 more Smart Citation

Bathymetry and productivity of the southern Great Basin seaway, Nevada, USA: An evaluation of isotope and trace element chemistry in mid-Carboniferous and modern brachiopods

Brand

Webster

Azmy

et al. 2007

Palaeogeography, Palaeoclimatology, Palaeoecology

View full text Add to dashboard Cite

The stable isotope and trace element chemistry of brachiopods from stratigraphically, paleontologically, and geochemically three coeval intervals about the mid-Carboniferous boundary in the Bird Spring Formation were evaluated for their potential of serving as proxies of bathymetry and productivity of the southern Great Basin seaway, an eastern arm of the Panthalassa Ocean. Oxygen isotopes delineate both spatial and temporal differences in values of brachiopods from the three coeval mid-Carboniferous sections. Based on pristine brachiopod δ 18 O values and supported by paleoecological information, water depth increased from Apex to Kane Springs Wash East to Arrow Canyon. In addition, there is also an increase in values from the latest Mississippian to the earliest Pennsylvanian suggesting a water temperature (cooling), a water depth (increase), and/or change in both of the habitat of the penecontemporaneous brachiopods.Analogous to values and trends observed in modern brachiopods, the Fe/Mn ratio of fossil counterparts may be a potential proxy of seawater productivity related to the micronutrient iron. Overall, the high ratios of Fe/Mn suggest highly productive waters for the southern Great Basin seaway, with somewhat reduced productivity during the earliest Pennsylvanian. In contrast, the carbon isotope values of the coeval material are relatively invariant with respect to productivity; trends similar to observations on modern carbonate allochems. Based on habitat and paleogeography, the Antler Orogenic Highlands west of the foreland basin are considered a potential source for the micronutrient iron enrichment of the carbonate platform shelf-edge environment. It is further postulated that upwelling currents, in part, which weakened from the latest Mississippian through to the earliest Pennsylvanian, may have transported the micronutrient iron onto the shelf/basin environments of the Bird Spring Formation of the southern Great Basin.

show abstract

Interpreting carbon-isotope excursions: carbonates and organic matter

Cited by 982 publications

References 58 publications

Presentation, calibration and validation of the low-order, DCESS Earth System Model (Version 1)

Presentation, calibration and validation of the low-order, DCESS Earth System Model (Version 1)

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

Bathymetry and productivity of the southern Great Basin seaway, Nevada, USA: An evaluation of isotope and trace element chemistry in mid-Carboniferous and modern brachiopods

Contact Info

Product

Resources

About