Carbonate Precipitation and Dissolution

Canfield, Donald E.; Raiswell, R.

doi:10.1007/978-1-4899-5034-5_9

Cited by 112 publications

(26 citation statements)

References 116 publications

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“…Various lines of evidence (the deformation of host sediment laminae around concretions, the presence of uncrushed fossil material and septarian fissures) indicate that cementation must have been able to resist the effects of compaction, and thus must have been at least initiated at shallow burial depths (Raiswell and Fisher, 2000). These three lines of evidence are consistent with the porewater chemistry of modern sediments (Canfield and Raiswell, 1991), which are generally over-saturated with respect to CaCO 3 and dolomitic phases at shallow depths where organic carbon is undergoing microbial decay.…”

Section: Introductionsupporting

confidence: 56%

“…The DSDP/ODP sediments are all oversaturated with respect to both calcite and dolomite (see Table 2), which would seem to preclude the supply of additional Ca 2+ from the dissolution of biogenic calcareous debris during sulphate reduction. However diagenetic models (Canfield and Raiswell, 1991;Boudreau and Canfield, 1993) predict that calcite and aragonite can become under-saturated if sulphide acumulates in the porewaters during the early stages of sulphate reduction (removal of up to 5-7 mM SO 4 2-). Such under-saturation must be confined to micro-environments (since the bulk SI values in the DSDP/ODP sediments indicate over-saturation), which would suggest that carbonate dissolution could only have a limited impact during sulphate reduction (the dissolution of biogenic carbonate may however be a significant source during subsequent burial).…”

Section: Additional Ca 2+ Sources During Sulphate Reductionmentioning

confidence: 99%

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Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments: implications for the formation of concretions

Raiswell

Fisher

2004

Chemical Geology

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Abstractduring sulphate depletion over these depth ranges are equivalent to a dispersed phase of approximately 1.5 wt.% CaCO 3 or 3 wt.% dolomite in a compacted sediment. The complete occlusion of sediment porosity observed in concretions with isotopic signatures suggesting carbonate sourced from sulphate reduction therefore requires more time (a depositional hiatus), 1 more rapid sulphate reduction (possibly by anaerobic methane oxidation) and/or the continued transport of isotopically light carbonate to the concretion site after sulphate reduction has ceased.

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Section: Introductionsupporting

confidence: 56%

Section: Additional Ca 2+ Sources During Sulphate Reductionmentioning

confidence: 99%

Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments: implications for the formation of concretions

Raiswell

Fisher

2004

Chemical Geology

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“…Carbonate dissolution within a (former) sapropel is excluded, because this carbonate-poor layer is not a remnant of a sapropel, as becomes evident from the low Ba contents (see below, Section 4.2). Additionally, only in the early stages of sulphate reduction, a decrease in pH would be expected (Canfield and Raiswell, 1991). On the other hand, pervasive sulphate-reducing conditions will produce alkalinity that enhances the preservation of carbonate (Sholkovitz, 1973).…”

Section: The Exotic Layer: Mineralogical and Geochemical Constraintsmentioning

confidence: 99%

Geochemistry of an exotic sediment layer above sapropel S-1: mud expulsion from the Urania Basin, eastern Mediterranean?

et al. 2003

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In a gravity core from the eastern Mediterranean Sea, a chemically and mineralogically distinct, 5.5-cmthick layer is present above sapropel S-1 and overlain by hemipelagic marls. Calcite is completely absent in this exotic layer, dolomite is present only in small amounts, and the Cr concentrations are significantly enhanced. The layer was deposited primarily under reducing conditions, but the distributions of redoxsensitive elements show that a large part of the exotic layer is now oxidised by a downward-progressing oxidation front. Sediments from within the nearby anoxic, hypersaline Urania Basin are similar to those from the exotic layer, in particular in S-, C-, and O-isotope distributions of pyrite and dolomite, as well as increased Cr concentrations. Mud expulsion due to expansion of gas-rich mud is proposed to explain the presence of the exotic layer outside the Urania Basin. The deposition of an anoxic layer above S-1 shielded the sapropel from oxidation which resulted in the rare occurrence of a complete preservation of S-1 and provides the first minimum age for the start of anoxic mud accumulation in the Urania Basin.

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“…1A). (1) After deposition, an aragonitebearing sediment layer is slowly buried and passes through a stationary aragonite dissolution zone (presumably related to bacterial activity; see Canfield and Raiswell 1991), where aragonitic constituents are selec- Munnecke and Samtleben (1996). Sediment moves through stable diagenetic zones where aragonite dissolution and calcite cementation take place.…”

Section: Approachmentioning

confidence: 99%

Orbital frequencies in the carbonate sedimentary record: distorted by diagenesis?

Westphal¹,

Böhm

Bornholdt

2004

Facies

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The most important archive of Earth's climate change through geologic history is the sedimentary rock record. Rhythmic sedimentary alternations are usually interpreted as a consequence of periodic variations in the orbital parameters of the Earth. This interpretation enables the application of cyclostratigraphy as a very precise chronometer, when based on the assumption that orbital frequencies are faithfully recorded in the sedimentary archive. However, there are numerous uncertainties with the application of this concept. Particularly in carbonates, sediment properties such as mineralogical composition and fossil associations are severely altered during post-depositional alteration (diagenesis). We here point out that the assumption of a 1:1 recording of orbital signals in many cases is questionable for carbonate rhythmites. We use computer simulations to show the effect of diagenetic overprint on records of orbital signals in the carbonate record. Such orbital signals may be distorted in terms of frequency, amplitude, and phase by diagenetic processes, and cycles not present in the insolation record may emerge. This questions the routine use of carbonate rhythmites for chronostratigraphic dating.

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Carbonate Precipitation and Dissolution

Cited by 112 publications

References 116 publications

Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments: implications for the formation of concretions

Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments: implications for the formation of concretions

Geochemistry of an exotic sediment layer above sapropel S-1: mud expulsion from the Urania Basin, eastern Mediterranean?

Orbital frequencies in the carbonate sedimentary record: distorted by diagenesis?

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