Ikaite, CaCO<sub>3</sub>·6H<sub>2</sub>O: Cold comfort for glendonites as paleothermometers

Swainson, I. P.; Hammond, Robert P.

doi:10.2138/am-2001-11-1223

Cited by 61 publications

(50 citation statements)

References 9 publications

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“…Growth habits herein are similar to those illustrated from rocks throughout the geological record (for illustrations and reviews see Kaplan, 1979;Shearman and Smith, 1985;De Lurio and Frakes, 1999). Crystal morphology is compatible with glendonite pseudomorphs of various names (Dana, 1884;Shearman and Smith, 1985;Swainson and Hammond, 2001) but is unlike that of aragonite (Riccioni et al, 1996). Whereas most glendonites are calcite pseudomorphs (Swainson and Hammond, 2001), interpreted ferroan dolomite crystal pseudomorphs are documented from Cryogenian Neoproterozoic limestones (Spencer, 1971;Johnston, 1995).…”

Section: Stellate Dolomite and Its Interpretationsupporting

confidence: 70%

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

James¹,

Narbonne²,

Dalrymple³

et al. 2005

Geol

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Stellate crystals of ferroan dolomite in neritic siliciclastic and carbonate sedimentary rocks between Sturtian and Marinoan glaciations in the Mackenzie Mountains are interpreted as replaced glendonites. These pseudomorphs after ikaite indicate that shallow seawater at that time was near freezing. Stromatolites verify that paleoenvironments were in the photic zone and physical sedimentary structures such as hummocky cross-bedding confirm that the seafloor was repeatedly disturbed by storms. Glendonites within these low-latitude, continental shelf to coastal sedimentary deposits imply that global ocean water during much of Cryogenian time was likely very cold. Such an ocean would easily have cooled to yield widespread sea ice and, through positive feedback, growth of lowlatitude continental glaciers. In this situation gas hydrates could have formed in shallowwater, cold shelf sediment, but would have been particularly sensitive to destabilization as a result of sea-level change. Co-occurrence of pisolites and glendonites in these rocks additionally implies that some ooids and pisoids might have been, unlike Phanerozoic equivalents, characteristic of cold-water sediments.

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Section: Stellate Dolomite and Its Interpretationsupporting

confidence: 70%

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

James¹,

Narbonne²,

Dalrymple³

et al. 2005

Geol

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“…The presence of pseudomorphs of calcite after authigenic ikaite in sediments, such as the glendonites, has an important use in palaeoclimatology as a proxy representing conditions of formation in water of near-freezing conditions (Suess et al, 1982;Swainson and Hammond, 2001). These are found in a variety of different facies, including those of the cool-water carbonates.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen bonding in ikaite, CaCO₃.6H₂O

Swainson¹,

Hammond²

2003

Mineral. mag.

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Ikaite is a metastable hexahydrate of calcium carbonate, forming in aqueous conditions near freezing conditions. Neutron powder diffraction data of synthetic deuterated ikaite, collected at seven temperatures from 4 to 270 K, were refined. The linear thermal expansion coefficients are quite anisotropic, being smaller in the direction of the C -O bond. A review of the hydrogen-bonding scheme around the (CaCO 3 0 ) ion pair is given and an additional weak potential hydrogen bond is suggested. Temperature-dependent growth of the atomic displacement factors of the carbonate O1 atom agrees with the previous suggestion of a possible low-frequency, hindered librational mode of the carbonate group.KEY WORDS: ikaite, hydrogen bonding, powder neutron diffraction, calcium carbonate hexahydrate.

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“…These elements all point towards the porphyroblast being glendonite (Fig. 1f), a pseudomorph of hydrated calcium carbonate, ikaite (Swainson & Hammond 2001). The pseudomorphs are typically small in comparison with modern examples of glendonite, but bear a remarkable similarity in crystal morphology to those from recent sediments (Fig.…”

Section: Origin Of the Porphyroblastsmentioning

confidence: 93%

“…1f), although interpenetrating and stellate forms commonly present in the latter (James et al 2005) have not been observed. Ikaite is replaced by calcite with a volume change of c. 67% (Swainson & Hammond 2001) and fibrous quartz grows into the resulting cavities. Locally minor warping of the external fabric occurs associated with this volume reduction around the ends of the porphyroblast.…”

Section: Origin Of the Porphyroblastsmentioning

confidence: 99%

“…Ikaite is stable at very low temperatures (Marland 1975) at, or just below, the sediment-water interface (Pauly 1963;Suess et al 1982) and glendonite has been used as a palaeoenvironmental indicator of near-freezing surface conditions (Swainson & Hammond 2001;James et al 2005;Selleck et al 2007). Ikaite may grow within sea-ice brines (Dieckmann et al 2008) and during shallow diagenesis within organic-rich sediments (Suess et al 1982), but all examples from the geological record are replaced by aggregates of calcite (Huggett et al 2005).…”

Section: Conditions Of Growth and Cause Of Metamorphismmentioning

confidence: 99%

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Ikaite pseudomorphs in Neoproterozoic Dalradian slates record Earth’s coldest metamorphism

Dempster

Jess

2015

JGS

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Calcite pseudomorphs have replaced euhedral ikaite (CaCO 3 .6H 2 O) porphyroblasts in Dalradian calcareous slates and metadolostones of western Scotland, with a volume decrease of at least 47%. Porphyroblast–fabric relationships indicate that the initial growth of ikaite post-dates a penetrative tectonic fabric developed during upright folding. This is the first reported occurrence of metamorphic ikaite porphyroblasts and points towards growth within the slates during an ultra-low-temperature metamorphism with an exceptionally low geothermal gradient. This event is associated with the penetration of long-lived and extreme permafrost deep into subaerially exposed bedrock during Neoproterozoic glaciation. The presence of the well-preserved pseudomorphs within the Easdale slates of the Argyll Group implies that a Neoproterozoic orogenic unconformity exists above the stratigraphic position of these rocks.

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Ikaite, CaCO₃·6H₂O: Cold comfort for glendonites as paleothermometers

Cited by 61 publications

References 9 publications

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

Hydrogen bonding in ikaite, CaCO₃.6H₂O

Ikaite pseudomorphs in Neoproterozoic Dalradian slates record Earth’s coldest metamorphism

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Ikaite, CaCO3·6H2O: Cold comfort for glendonites as paleothermometers

Cited by 61 publications

References 9 publications

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates

Hydrogen bonding in ikaite, CaCO3.6H2O

Ikaite pseudomorphs in Neoproterozoic Dalradian slates record Earth’s coldest metamorphism

Contact Info

Product

Resources

About

Ikaite, CaCO₃·6H₂O: Cold comfort for glendonites as paleothermometers

Hydrogen bonding in ikaite, CaCO₃.6H₂O