Publication Date:
2021-03-29
Description:
According to a model by Cerling (1991, 1999), the carbon isotope composition
of calcretes should depend on the soil type and the CO2-concentration in the atmosphere.
We have tested Cerling’s model by investigating 14 Palaeozoic sections with
soil profiles. A large number of carbonate types of different genetic origin exist in the
localities examined. Comparing the Palaeozoic samples with recent and subrecent
calcretes, it can be demonstrated that anhedral, cryptocrystalline (〈10 μm) and
subhedral microcrystalline (10 - 40 μm) carbonates are clearly of pedogenic origin.
Crystals of larger size with a poikilotopic texture are of groundwater or burial diagenetic
origin. Macro- and micromorphological features, typical of recent calcretes,
occur in several soil profiles, but thin section microscopy reveals a strong diagenetic
overprint of most pedogenic carbonates. Time equivalent sections with comparable
soil types (protosols, calcisols and vertisols) show large variations in carbon isotope
composition. On the other hand, different carbonate generations at one site do not
differ much. Therefore Palaeozoic calcretes appear to be unsuitable for a deduction
of the Palaeozoic CO2-concentration.
Description:
German Research Foundation (DFG)
Description:
research
Keywords:
551.9
;
552.5
;
VKB 350
;
VJJ 110
;
VCA 300
;
VKB 332
;
VKA 300
;
VKB 371
;
VEA 000
;
VKB 372
;
Lithogenese {Sedimentologie}
;
Geochemie der Stabilen Isotopen
;
Paläozoische Geologie
;
Sedimentationsbedingungen
;
Petrogenese
;
Klastische Sedimentgesteine
;
Europa insgesamt {Geologie}
;
Karbonatische Sedimentgesteine
;
Kohlenstoffkreislauf
;
C-isotope
;
Jungpaläozoikum
;
Paläopedologie
;
Kalkkruste
;
CO2
;
calcrete
;
carbon cycle
;
upper Paleozoic
;
paleosol
;
C-13/C-12
;
Europa
;
paläoklima
;
Europe
;
38.41
;
38.61
;
38.32
Language:
English
Type:
article
Format:
application/pdf
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