The relationship between temperature and O content relative to that for a Cretaceous belemnite of the Pee Dee formation previously reported (Epstein, Buchsbaum, Lowenstam, and Urey, 1951) has been redetermined using modified procedures for removing organic matter from shells, and is found to be t (°O = 16.5 4.38 + 0.145*, where 8 is the difference in per mil of the O to O ratio between the samp...

The Mt Weld lanthanide deposit in central Western Australia is considered to be one of the largest high grade deposits known in the world, first reported as a carbonate and phosphate rich ultramafic silicate intrusion that contained a resource of the Lanthanide series [1]. It has been dated between 1.6 – 2.0 billion years, where the formation of a carbonate layer in the cooling melt created a p...

The subject of the present paper is the derivation and asymptotic analysis of a mathematical model for the formation of a mushy region during sulphation of calcium carbonate. The model is derived by averaging, with the use of the multiple scales method, applied on microscopic moving boundary problems. The latter problems describe the transformation of calcium carbonate into gypsum on the micros...

Microproblematica are microfossils whose suprageneric taxonomic status is unknown. Many microproblematica display an encrusting way of life and can therefore be included in the group of “micro-encrusters” that during the Upper Jurassic were conspicuous components of microbial carbonate crusts (e.g. LEINFELDER et al., 1993; SCHMID, 1996; DUPRAZ & STRASSER, 1999, 2002). These forms are widespread...

Carbonates of the Ojo Huelos Member of the San Pedro Arroyo Formation include ostracodal limestones, brecciated micritic limestones, vuggy, mottled limestones, peloidal graistones/packstones, pisolitic rudstones and nodular limestones. These lithofacies record deposition in lacustrine, palustrine and alluvial environments. Lacustrine (ostracodal) limestones are isotopically heaviest, with nodul...

Using updated and improved atomistic models for the polymorphs of calcium carbonate and their constituent ions in solution, we revisit the question of surface energetics and nanoparticle stability. Using a simple lattice-based Monte Carlo scheme, we generate nanoparticle configurations in vacuum for all three biologically relevant polymorphs of calcium carbonate and establish that the bulk ener...

The synthesis of two high nuclearity lanthanoid clusters demonstrates the versatility of the carbonate anion as a robust cluster forming agent, potentially allowing for the formation of otherwise inaccessible core topologies. The complexes, [Gd(14)(CO(3))(13)(ccnm)(9)(OH)(H(2)O)(6)(phen)(13)(NO(3))](CO(3))(2.5)·(phen)(0.5) (1) and [Dy(14)(CO(3))(13)(ccnm)(10)(OH)(H(2)O)(6)(phen)(13)](CO(3))(2.5...

Molluscan nacre is a fascinating biomineral consisting of a highly organized calcium carbonate composite that provides unique fracture toughness and an iridescent color. Organisms elaborately control biomineralization using organic macromolecules. We propose the involvement of the matrix protein Pif80 from the pearl oyster Pinctada fucata in the development of the inorganic phase during nacre b...

[1] Despite in situ analyses by several landers, the composition of the Martian soil remains unclear. Recently, constituent minerals in the soil have been proposed from thermal emissivity and Mössbauer spectroscopic data from Mars. These data were interpreted to show spectral evidence for carbonate and an unspecified mineral containing bound water, as well as olivine. Here we present an alterna...

An azacryptand has been solubilised in aqueous media containing 50% (v/v) dimethyl sulphoxide. (13)C-NMR has been used to determine how the azacryptand is affected by zinc binding at pH 10. Using (13)C-NMR and (13)C-enriched bicarbonate we have been able to observe the formation of 4 different carbamate derivatives of the azacryptand at pH 10. The azacryptand was shown to solubilise zinc or cad...