An oscillating trend in Phanerozoic non-skeletal carbonate mineralogy

  title={An oscillating trend in Phanerozoic non-skeletal carbonate mineralogy},
  author={P. Sandberg},
Textural and compositional data on ancient ooids and cements suggest the existence of an oscillating Phanerozoic temporal trend in non-skeletal carbonate mineralogy. The trend shows good correlation with eustatic–climatic oscillations proposed by others. The most likely mechanism appears to be plate-tectonically influenced oscillations in PCO2, the vapour pressure of CO2, rather than change in oceanic Mg/Ca ratio. 
Palaeoecological evidence for early aragonite dissolution in ancient calcite seas
It has been proposed that shallow carbonate seas of Upper Ordovician and Jurassic ages precipitated calcite as the primary calcium carbonate phase1–3, unlike such settings today. It is expected thatExpand
Palaeoceanography: Seeing changes in a changing sea
The ratio of magnesium to calcium in sea water is thought to have influenced the skeletal mineralogy of certain marine calcifiers throughout the Phanerozoic eon. A fresh look at old data suggestsExpand
Diagenetic evolution of a Late Silurian reef platform, Gaspé Basin, Quebec, based on cathodoluminescence petrography
Carbonate units of two facie of the platformal upper reef complex of the Late Silurian West Point Formation, Gaspe Peninsula, Quebec, were studied to decipher their diagenetic evolution. The two fa...
Genesis of the Eastern Paratethys manganese ore giants: impact of events at the Eocene/Oligocene boundary
Abstract The giant Mn ore deposits of the Paratethys are located on the slopes and/or margins of deep basins. The Eocene ocean and associated basins were strongly influenced by large-scale submarineExpand
Explaining the Phanerozoic Ca isotope history of seawater
A new geochemical budget for the modern marine carbonate sink helps to explain the major features of the Phanerozoic Ca isotope record. A large compilation of Ca isotope ratios for modern carbonates,Expand
Hypercalcification: Paleontology Links Plate Tectonics and Geochemistry to Sedimentology
During the Phanerozoic Eon, the mineralogies of nonskeletal marine cements and oolites have oscillated on a 100‐200 m.y. scale between aragonite ± high-Mg calcite (aragonite seas) and low-Mg calciteExpand
Diagenetic and Sea-Level Controls on Porosity Evolution for Oolitic and Crinoidal Carbonates of the Mississippian Keokuk Limestone and Warsaw Formation
Submitted to the Department of Geology and the Faculty of the Graduate School of the University of Kansas in partial fulfillment of the requirements for the degree of Master of Science. viii, 149Expand
Petrology and diagenetic evolution of Neoproterozoic ooids (Libby Formation, western Montana, U.S.A.)
Abstract Radial/concentric and twinned/sparry ooids from the upper Belt Supergroup originally formed as mixed Mgcalcite and aragonite, and aragonite. Textural evidence suggests that Mgcalcite ooidsExpand
Carbon isotopes and Precambrian—Cambrian boundary geology, South Australia: ocean basin formation, seawater chemistry and organic evolution
A carbon isotope stratigraphy from the lowest Cambrian strata in the Adelaide fold belt of South Australia is interpreted in terms of the geological context of the sequence: major transgression,Expand
Cyclic and secular variation in microfossil biomineralization: clues to the biogeochemical evolution of Phanerozoic oceans
The stratigraphic occurrence and mineralogy of major protistan microfossil taxa tend to reflect evolutionary innovation in response to ocean chemistry and fertility. In foraminefera, theExpand


Aragonitic Ultrastructural Relics in Calcite-replaced Pleistocene Skeletons
Skeletal aragonites incorporated into sedimentary rocks may undergo a variety of fates, but these are generally regarded as all-or-nothing phenomena; that is, either the aragonite is preservedExpand
Secular changes in marine inundation of USSR and North America through the Phanerozoic
Analysis of palaeogeographic and facies maps of the USSR and North America confirms an overall trend towards marine regression through the Phanerozoic with a major deviation in the late Mesozoic.Expand
Tepee structures and associated diagenetic features in intertidal carbonate sands (lower Jurassic, Morocco)
Abstract In southeastern Morocco, Early Jurassic inter- to supratidal carbonates can be followed for 200–300 km along the southern slopes of the High Atlas mountains. These beds form intervals ofExpand
Transformation of aragonite to calcite in a marine gasteropod
A detailed examination of the aragonite to calcite transformation in samples of Strombus gigas from the Pleistocene of British Honduras demonstrates that the process is essentially isochemical withExpand
Biomineralization, paleoceanography, and the evolution of calcareous marine organisms
In contrast to modern shallow-marine ooids and carbonate muds, which are composed for the most part of aragonite, Paleozoic counterparts probably were deposited with a primary calcite mineralogy,Expand
Tectonic controls of Phanerozoic sedimentary rock cycling
The cyclic nature of the Phanerozoic sedimentary rock distribution, carbon-sulphur coupling, and material transfer among sedimentary reservoirs appears to be controlled by tectonic factors. TheExpand
Aragonitic Fossils in the Lower Carboniferous of Scotland
ALTHOUGH many invertebrates form skeletons partly or wholly of aragonite, this normally inverts to calcite within a geologically negligible period of time, a few tens of thousands of years at theExpand
Isotopic and trace element evidence for submarine lithification of hardgrounds in the Jurassic of eastern England
Geochemical and petrographic data suggest early submarine cementation of hardgrounds from the Lincolnshire Limestone Formation, Middle Jurassic, England. The three hardgrounds, from Cowthick, CastleExpand
Carbonate diagenesis in Quaternary beachrock of Uyombo, Kenya: Sequences of processes and coexistence of heterogenic products
The calcareous quartz sandstone contains a variety of carbonate cements; these and the biogenic carbonate particles have been preserved and altered in various ways.Several inherited submarineExpand
Syn‐Sedimentary Marine Lithification of Middle Jurassic Limestones in the Paris Basin
SUMMARY Bored surfaces in Middle Jurassic limestones in northeastern France indicate syn-sedimentary lithification. The sedimentary structures and textures, and age relationships between the boredExpand