Ikaite, the parent mineral of jarrowite-type pseudomorphs

Shearman, D. J.; Smith, A. J.

doi:10.1016/s0016-7878(85)80019-5

Cited by 85 publications

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“…Less stable calcium carbonate forms that could have been the precursor are amorphous CaCO 3 , ikaite, vaterite or aragonite. Ikaite is an attractive option because it forms preferentially at low temperatures (Shearman & Smith, 1985;Selleck et al, 2007;Oehlerich et al, 2013) such as those expected to coincide with ice-rafting ; Fairchild et al (2016) have shown similar replacive rhombic calcite fabrics to those in basal E3 limestones in replaced ikaite of the Wilsonbreen Formation.…”

Section: Discussionmentioning

confidence: 99%

The Late Cryogenian Warm Interval, NE Svalbard: Chemostratigraphy and genesis

Fairchild

Bonnand²,

Davies

et al. 2016

Precambrian Research

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms At the base of E3, interstratification of cap carbonate with ice-rafted and redeposited glacial sediments occurs. Early diagenetic stabilization of carbonate mineralogy from a precursor, possibly ikaite, to calcite or dolomite is inferred. E3 is predominantly dolomitic silt-shale, with sub-millimetre lamination, lacking sand or current-related sedimentary structures. Thin fine laminae are partly pyritized and interpreted as microbial mats. Dolomite content is 25-50%, with δ 13 C values consistently around +4‰, a value attributed to buffering by dissolution of a precursor metastable carbonate phase. Local calcite cement associates with low δ 13 C values. The carbonates form silt-sized, chemically zoned rhombic crystals from an environment with dynamically changing Fe and Mn. Three-dimensional reconstructions of cm-scale disturbance structures indicate that they represent horizontally directed sock-like folds, developed by release of overpressure into thin surficial sediment overlying an early-cemented layer.A shoaling upwards unit near the top of E3 displays calcium sulphate pseudomorphs in dolomite in the north, but storm-dominated limestones in the south, both being overlain by peritidal oolitic dolomites, exposed under the succeeding Wilsonbreen glacial deposits. There is no Trezona δ 13 C anomaly, possibly implying top-truncation of the succession.Regular 0.5 m-scale sedimentary rhythms, reflecting subtle variations in sediment texture or composition occur throughout E3 and are interpreted as allocyclic. They are thought to be mainly primary in origin, locally modified slightly during early diagenetic cementation. Rhythms are proposed to represent ca. 18 kyr precession cycles, implying 6-8 Myr deposition between glaciations.

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Section: Discussionmentioning

confidence: 99%

The Late Cryogenian Warm Interval, NE Svalbard: Chemostratigraphy and genesis

Fairchild

Bonnand²,

Davies

et al. 2016

Precambrian Research

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“…The reason for doing this was to gather supporting evidence for the current suggestion that ikaite was the precursor mineral of the calcite pseudomorphs known as jarrowites, thinolites, glendonites and gennoishi etc. (Shearman & Smith, 1985). The ikaite crystals did become pseudomorphed into calcium carbonate, but the 0021-8898/90/040263-03503.00 XRD analysis showed the carbonate to be dominantly vaterite with a very small proportion of calcite.…”

Section: Introductionmentioning

confidence: 98%

A new crystal growth form of vaterite, CaCO3

Shaikh¹

1990

J Appl Crystallogr

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Microcrystalline vaterite, CaCO3, has been synthesized by decomposition of ikaite, CaCO3.6H20, crystals at room temperature. Scanning electron micrographs show that vaterite occurs as arborescent aggregates -30 to 40 txm in size. This growth form has not been described before. It is of interest that the overall morphology of the vaterite is reminiscent of some dendritic calcite tufas, although on a smaller scale. This similarity opens up the possibility that the calcitic tufas such as that associated with the Quaternary Lake Lahonton, Nevada, may have been deposited as vaterite that changed to calcite, while preserving the original growth form.

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Section: Introductionmentioning

confidence: 99%

“…The ease of breakdown of ikaite means that calcite pseudomorphs after ikaite are pre-served at the same time in the sedimentary record (Larsen, 1994). Glendonite, thinolite, jarrowite, fundylite, gennoishi, gersternkõrner, and White Sea hornlets are local names attributed to calcite pseudomorph after metastable ikaite (Shearman and Smith, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…Both in nature and in the laboratory, ikaite readily crystallizes from solution at temperatures near 0°C , but rapidly decomposes into a mush of anhydrous CaCO 3 and water at warmer temperatures (Bischoff et al, 1993;Council and Bennett, 1993;Mikkelsen et al, 1999;Tang et al, 2009 -168, 2014 served at the same time in the sedimentary record (Larsen, 1994). Glendonite, thinolite, jarrowite, fundylite, gennoishi, gersternkõrner, and White Sea hornlets are local names attributed to calcite pseudomorph after metastable ikaite (Shearman and Smith, 1985).Journal of Mineralogical and Petrological Sciences, Volume 109, page 157Ikaite crystallizes in the monoclinic space group C2/ c with a = 8.8053(2), b = 8.3138(1), c = 11.0328(3) Å, β = 110.598(3)°, Z = 4, and V = 756.03(5) Å 3 at a temperature of −30°C (Lennie et al, 2004). The ikaite structure comprises discrete CaCO 3 ·6H 2 O molecules linked together by hydrogen bonding in a unit cell (Lennie et al, 2004).…”

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Structural change induced by dehydration in ikaite (CaCO3·6H2O)

Tateno

Kyono

2014

Journal of Mineralogical and Petrological Sciences

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Dehydration-induced structural change in ikaite, CaCO 3 ·6H 2 O, is investigated using a low-temperature singlecrystal X-ray diffraction study. At −50°C, the crystal structure of ikaite is monoclinic, of space group C2/c with the unit cell parameters a = 8.8134 (1), b = 8.3108 (1), c = 11.0183 (1) Å, and β = 110.418 (1)°. The measurements were performed in 10°C steps, revealing a monotonous increase of unit cell volume from 756.3 to 758.0 Å 3 , up to −20°C. The unit cell volume then jumps to 771.0 Å 3 at −10°C. The unit cell expands anisotropically along the a-axis followed by the c-axis. The ikaite structure is finally lost at 0°C, which is a much lower temperature for decomposition than previously reported values. The low temperature decomposition is attributable to the aridity of the sample. The elongation of the O1-O4 intermolecular distance parallel to the (101) plane engenders the substantial increase in the a-axis and c-axis. The two-dimensional molecular sheets composed of the CaCO 3 ·6H 2 O molecules are stacked with hydrogen bondings along the c-axis. The expansion of the c-axis is affected by variations in the hydrogen bondings between the sheets. The intramolecular Ca-O2 and Ca-O5 bond lengths and the intermolecular O1-O5 distance are greatly elongated immediately before the decomposition of ikaite structure. These expansions along the b-axis, however, are offset by the increase in the O2-C-O2 bond angle in the CO 3 geometry, aligned perfectly parallel to the b-axis. The intermolecular angles are maintained as almost constant until the ikaite structure is lost. It can be concluded therefore that the movement of H 2 O molecules from the crystal lattice occurs simultaneously because the CaCO 3 ·6H 2 O molecules are stabilized by the hydrogen-bonding network immediately before dehydration.Keywords: Calcium carbonate hydrate, Decomposition, Phase transition, Low-temperature single-crystal X-ray diffraction INTRODUCTIONCalcium carbonates are abundant materials found in sedimentary rock throughout Earth's surface. During the past two decades, much research has been conducted on calcium carbonate nucleation, given that abiotic precipitation of calcium carbonate minerals constitutes a huge sink of CO 2 gas from the atmosphere, which directly affects the ocean chemistry, Earth's atmosphere, and climate (e.g., Archer and Maier-Reimer, 1994;Kleypas et al., 1999;Riebesell et al., 2000;Ries et al., 2009;Bodnar et al., 2013;Kaszuba et al., 2013). Calcium carbonate minerals occur naturally in six different modifications: three anhydrous crystalline polymorphs (CaCO 3 ) as calcite, aragonite, and vaterite; two hydrate phases as monohydrocalcite (CaCO 3 ·H 2 O) and ikaite (CaCO 3 ·6H 2 O); and amorphous calcium carbonate (ACC), which has similar stoichiometry to that of monohydrocalcite (LeviKalisman et al., 2002). Ikaite is a metastable mineral in the sedimentary realm formed naturally from aqueous solutions in near-freezing anoxic marine sediments (Zabel and Schulz, 2001;Greinert and Derkachev, 2004;Selleck et al.,...

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Ikaite, the parent mineral of jarrowite-type pseudomorphs

Cited by 85 publications

References 9 publications

The Late Cryogenian Warm Interval, NE Svalbard: Chemostratigraphy and genesis

The Late Cryogenian Warm Interval, NE Svalbard: Chemostratigraphy and genesis

A new crystal growth form of vaterite, CaCO3

Structural change induced by dehydration in ikaite (CaCO3·6H2O)

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