Oxygen isotopic equilibrium between carbon dioxide and water in soils

Tellus B ◽  
1998 ◽  
Vol 50 (2) ◽  
pp. 163-178 ◽  
Author(s):  
PIETER P. TANS
Keyword(s):  
Carbon Dioxide ◽  
Isotopic Equilibrium ◽  
Oxygen Isotopic

Forsterite reprecipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic–alkaline–carbonatite complex, Meghalaya, NE India

2020 ◽  
pp. 1-12
Author(s):  
Shubham Choudhary ◽  
Koushik Sen ◽  
Santosh Kumar ◽  
Shruti Rana ◽  
Swakangkha Ghosh
Keyword(s):  
Carbon Dioxide ◽  
Lithospheric Mantle ◽  
Experimental Studies ◽  
Carbonatite Complex ◽  
Kerguelen Plume ◽  
Ne India ◽  
Isotopic Analyses ◽  
Oxygen Isotopic ◽  
Carbonatite Magma

Abstract Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2–H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2–H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution–precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2–H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.

scholarly journals Potential of Stable Carbon and Oxygen Isotope Variations of Speleothems from Andaman Islands, India, for Paleomonsoon Reconstruction

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Amzad H. Laskar ◽  
S. Raghav ◽  
M. G. Yadava ◽  
R. A. Jani ◽  
A. C. Narayana ◽  
...  
Keyword(s):  
Monsoon Rainfall ◽  
Boreal Summer ◽  
Stable Carbon ◽  
The South ◽  
Isotopic Equilibrium ◽  
The Past ◽  
Carbon And Oxygen Isotope ◽  
Show Evidence ◽  
Oxygen Isotopic ◽  
India Receive

The Indian monsoon activity, coinciding with the Inter-Tropical Convective Zone (ITCZ), progresses from the southern Indian Ocean during the boreal summer and withdraws towards the south in winter. Islands situated to the south of India receive, therefore, the first and last showers of the monsoon; speleothems in such islands have not yet been explored for their potential to reconstruct past monsoon rainfall. Here, we present the first measurements of stable carbon and oxygen isotopic compositions (δ13C and δ18O) of a stalagmite collected from the Baratang Island of Andamans, along with new data on δ18O of modern monsoon precipitation (May to July 2010). The aim was to detect (i) whether these samples are amenable to dating using 14C, (ii) whether their oxygen isotopes indicate precipitation under isotopic equilibrium, and (iii) if (i) and (ii) above are true, can we reconstruct monsoon activity during the past few millennia? Our results indicate that while δ18O of speleothem does show evidence for precipitation under isotopic equilibrium; dating by 14C shows inversions due to varying contributions from dead carbon. The present work highlights the problems and prospects of speleothem paleomonsoon research in these islands.

On the time required to establish chemical and isotopic equilibrium in the carbon dioxide system in seawater

1999 ◽  
Vol 65 (3-4) ◽  
pp. 135-153 ◽  
Author(s):  
Richard E. Zeebe ◽  
D.A. Wolf-Gladrow ◽  
H. Jansen
Keyword(s):  
Carbon Dioxide ◽  
Isotopic Equilibrium ◽  
Time Required

Chemical and oxygen isotopic properties of ordinary chondrites (H5, L6) from Oman: Signs of isotopic equilibrium during thermal metamorphism

2017 ◽  
Vol 52 (10) ◽  
pp. 2097-2112 ◽  
Author(s):  
Arshad Ali ◽  
Sobhi J. Nasir ◽  
Iffat Jabeen ◽  
Ahmed Al Rawas ◽  
Neil R. Banerjee ◽  
...  
Keyword(s):  
Ordinary Chondrites ◽  
Isotopic Equilibrium ◽  
Thermal Metamorphism ◽  
Oxygen Isotopic

scholarly journals A modeling investigation of canopy-air oxygen isotopic exchange of water vapor and carbon dioxide in a soybean field

2010 ◽  
Vol 115 (G1) ◽  
Author(s):  
Wei Xiao ◽  
Xuhui Lee ◽  
Timothy J. Griffis ◽  
Kyounghee Kim ◽  
Lisa R. Welp ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Isotopic Exchange ◽  
Soybean Field ◽  
Oxygen Isotopic

scholarly journals Stable-Isotope Ratios and Concentration of CO2 in Air from Polar Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 151-156 ◽  
Author(s):  
U. Siegenthaler ◽  
H. Friedli ◽  
H. Loetscher ◽  
E. Moor ◽  
A. Neftel ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Isotope Fractionation ◽  
Ice Core ◽  
Ice Cores ◽  
South Pole ◽  
Polar Ice ◽  
Isotopic Equilibrium ◽  
Calculated Equilibrium ◽  
Fractionation Factors

Analyses of air trapped in an ice core from the South Pole indicate that the CO2 concentration may have increased by about 10 ppm and that the 13C/12C ratio decreased slightly in the thirteenth century. These changes, if really of atmospheric origin, must be due to a significant input into the atmosphere of CO2, either of biogenic or of oceanic origin. 18O/16O ratios in CO2 from different ice cores are much lower than those which have been observed in atmospheric carbon dioxide. A possible explanation is that the CO2 has equilibrated isotopically with the ice. We have calculated equilibrium isotope-fractionation factors between ice and carbon dioxide and found that the observed 18O/16O ratios of CO2 are indeed near isotopic equilibrium with the ice. This indicates that an exchange of oxygen atoms probably occurs between ice and included CO2.

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