Pedogenic origin of dolomite in a basaltic weathering profile, Kohala peninsula, Hawaii

Capo, Rosemary C.; Whipkey, Charles E.; Blachère, J. R.; Chadwick, Oliver A.

doi:10.1130/0091-7613(2000)28<271:poodia>2.0.co;2

Cited by 73 publications

(21 citation statements)

References 22 publications

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“…Under such conditions, a porewater with carbonate saturation does not reach smectite saturation because of the fast precipitation rates of carbonates (e.g., Busenberg and Plummer, 1986;Pokrovsky and Schott, 2002). Indeed, carbonate precipitation is usually correlated with specific conditions such as large amounts of carbonates in host rocks, degassing of CO 2 from solution and temporal, intense evaporation (Wang et al, 1994;Berner and Berner, 1996;Capo et al, 2000). Thus, porewater compositions are close to the saturation of clay minerals (Lasaga et al, 1994).…”

Section: Ph Constraints From Secondary Mineralsmentioning

confidence: 94%

Estimates of atmospheric CO2 in the Neoarchean–Paleoproterozoic from paleosols

Kanzaki

Murakami

2015

Geochimica et Cosmochimica Acta

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Section: Ph Constraints From Secondary Mineralsmentioning

confidence: 94%

Estimates of atmospheric CO2 in the Neoarchean–Paleoproterozoic from paleosols

Kanzaki

Murakami

2015

Geochimica et Cosmochimica Acta

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“…The evolution of Sr isotopic signatures from seashore towards 100-200 km inland is often interpreted as a result of the decreasing influence of sea salts (Quade et al, 1995;Capo et al, 2000;Whipkey et al, 2002;Rech et al, 2003;Dart et al, 2007). For pedogenic carbonates beyond 200 km inland, the proportion of in situ weathering versus atmospheric sources is still poorly understood.…”

Section: Sources Of Ca In the Pedogenic Carbonatesmentioning

confidence: 99%

Formation and preservation of pedogenic carbonates in South India, links with paleo-monsoon and pedological conditions: Clues from Sr isotopes, U–Th series and REEs

Violette

Riotte

Braun

et al. 2010

Geochimica et Cosmochimica Acta

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The influence of the pedogenic and climatic contexts on the formation and preservation of pedogenic carbonates in a climosequence in the Western Ghats (Karnataka Plateau, South West India) has been studied. Along the climosequence, the current mean annual rainfall (MAR) varies within a 80 km transect from 6000 mm at the edge of the Plateau to 500 mm inland. Pedogenic carbonates occur in the MAR range of 500-1200 mm. In the semi-arid zone (MAR: 500-900 mm), carbonates occur (i) as thick hardpan calcretes on pediment slopes and (ii) as nodular horizons in polygenic black soils (i.e. vertisols). In the sub-humid zone (MAR: 900-1500 mm), pedogenic carbonates are disseminated in the black soil matrices either as loose, irregular and friable nodules of millimetric size or as indurated botryoidal nodules of centimetric to pluricentimetric size. They also occur at the top layers of the saprolite either as disseminated pluricentimetric indurated nodules or carbonate-cemented lumps of centimetric to decimetric size.Chemical and isotopic ( 87 Sr/ 86 Sr) compositions of the carbonate fraction were determined after leaching with 0.25 N HCl. The corresponding residual fractions containing both primary minerals and authigenic clays were digested separately and analyzed. The trend defined by the 87 Sr/ 86 Sr signatures of both labile carbonate fractions and corresponding residual fractions indicates that a part of the labile carbonate fraction is genetically linked to the local soil composition. Considering the residual fraction of each sample as the most likely lithogenic source of Ca in carbonates, it is estimated that from 24% to 82% (55% on average) of Ca is derived from local bedrock weathering, leading to a consumption of an equivalent proportion of atmospheric CO 2 . These values indicate that climatic conditions were humid enough to allow silicate weathering: MAR at the time of carbonate formation likely ranged from 400 to 700 mm, which is 2-to 3-fold less than the current MAR at these locations.The Sr, U and Mg contents and the ( 234 U/ 238 U) activity ratio in the labile carbonate fraction help to understand the conditions of carbonate formation. The relatively high concentrations of Sr, U and Mg in black soil carbonates may indicate fast 0016-7037/$ -see front matter Ó Geochimica et Cosmochimica Acta 74 (2010) 7059-7085 growth and accumulation compared to carbonates in saprolite, possibly due to a better confinement of the pore waters which is supported by their high ( 234 U/ 238 U) signatures, and/or to higher content of dissolved carbonates in the pore waters. The occurrence of Ce, Mn and Fe oxides in the cracks of carbonate reflects the existence of relatively humid periods after carbonate formation. The carbonate ages determined by the U-Th method range from 1.33 ± 0.84 kyr to 7.5 ± 2.7 kyr and to a cluster of five ages around 20 kyr, i.e. the Last Glacial Maximum period. The young occurrences are only located in the black soils, which therefore constitute sensitive environments for trapping and retaining atmosphe...

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“…Their average composition is shown in Table 3 and plotted on geochemical profiles (Fig. Capo et al 2000;Knauth et al 2003). However, from the contact with the KSF downward for as much as 2 m, these volcanic rocks are sericitised, calcitised and chloritised.…”

Section: Palaeosol (Unit I)mentioning

confidence: 99%

Palaeoproterozoic, rift-related, ¹³C-rich, lacustrine carbonates, NW Russia. Part I: Sedimentology and major element geochemistry

Melezhik

Fallick

2004

Earth and Environmental Science Transactions of the Royal Socie

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The 150-m-thick Kuetsjärvi Sedimentary Formation (KSF) from the Pechenga Greenstone Belt, NW Russia, is one of the key formations in the study of a positive δ13Ccarb excursion occurring globally in the Palaeoproterozoic. The KSF formed in an intracratonic rift setting and is sandwiched between two, 2-km-thick subaerially erupted volcanic units. The KSF was previously interpreted as shallow marine, but new data reported here indicate that it is a non-marine unit deposited on a deeply subaerially weathered surface mantling the underlying volcanic rocks. The lowermost part of the KSF represents an alluvial–fluvial plain, followed by a laterally and vertically variable succession of variegated to mottled fine-grained siliciclastic rocks and ‘red beds‘, dolostones containing stromatolite sheets, hydrothermal travertine deposits and abundant desiccation features (e.g.tepees, surfical silicified crusts and dissolution cavities), including probable pseudomorphed evaporites. Measured S and Corg concentrations for the carbonate and siliciclastic rocks are low. Combined, these features indicate that the carbonate rocks of the KSF accumulated in a shallow lacustrine setting. Major types of carbonate facies were formed by: (1) biologically-induced precipitation; (2) evaporitic removal of CO2 in a closed lake environment; and (3) chemical precipitation from thermal springs. Apparently, none of these carbonate facies was in full isotopic equilibrium with atmospheric CO2. This interpretation shows the importance of taking into account the interplay between global and local depositional factors when interpreting the isotopic signature of the KSF dolostones and its implication for the Palaeoproterozoic carbon isotope excursion

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Pedogenic origin of dolomite in a basaltic weathering profile, Kohala peninsula, Hawaii

Cited by 73 publications

References 22 publications

Estimates of atmospheric CO2 in the Neoarchean–Paleoproterozoic from paleosols

Estimates of atmospheric CO2 in the Neoarchean–Paleoproterozoic from paleosols

Formation and preservation of pedogenic carbonates in South India, links with paleo-monsoon and pedological conditions: Clues from Sr isotopes, U–Th series and REEs

Palaeoproterozoic, rift-related, ¹³C-rich, lacustrine carbonates, NW Russia. Part I: Sedimentology and major element geochemistry

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Pedogenic origin of dolomite in a basaltic weathering profile, Kohala peninsula, Hawaii

Cited by 73 publications

References 22 publications

Estimates of atmospheric CO2 in the Neoarchean–Paleoproterozoic from paleosols

Estimates of atmospheric CO2 in the Neoarchean–Paleoproterozoic from paleosols

Formation and preservation of pedogenic carbonates in South India, links with paleo-monsoon and pedological conditions: Clues from Sr isotopes, U–Th series and REEs

Palaeoproterozoic, rift-related, 13C-rich, lacustrine carbonates, NW Russia. Part I: Sedimentology and major element geochemistry

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Palaeoproterozoic, rift-related, ¹³C-rich, lacustrine carbonates, NW Russia. Part I: Sedimentology and major element geochemistry