Reconstructing Past Seawater Mg/Ca and Sr/Ca from Mid-Ocean Ridge Flank Calcium Carbonate Veins

  title={Reconstructing Past Seawater Mg/Ca and Sr/Ca from Mid-Ocean Ridge Flank Calcium Carbonate Veins},
  author={Rosalind M. Coggon and Damon A. H. Teagle and Christopher E. Smith-Duque and Jeffrey C. Alt and Matthew J. Cooper},
  pages={1114 - 1117}
Cations in the Veins Major events in Earth's history, from climate change to tectonic activity, can be revealed by reconstructing past conditions of the oceans. Clues from ancient ocean chemistry can be found in the cation content of fossilized microorganisms, marine carbonates, or salt deposits from old coastal zones. As these proxies are prone to inconsistencies between samples and methodologies, Coggon et al. (p. 1114, published online 4 February; see the Perspective by Elderfield) estimated… 
Seawater Chemistry and Climate
Coggon et al. address the problem of reliable archives of past seawater chemistry by measuring magnesium/calcium and strontium/cal calcium ratios in calcium carbonate (calcite) veins recovered from ocean crust buried under sediments.
Cenozoic global cooling and increased seawater Mg/Ca via reduced reverse weathering
The results suggest that global reorganizations of biogenic silica burial over the Cenozoic reduced marine authigenic clay formation, contributing to the rise in seawater Mg/Ca and decline in atmospheric CO2 over the past 50 million years.
A Cenozoic record of the equatorial Pacific carbonate compensation depth
A carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean is presented and large superimposed fluctuations in carbonate compensation depth are found during the middle and late Eocene.
A Cenozoic record of seawater Mg isotopes in well-preserved fossil corals
Reconstructions of seawater Mg isotopic composition (δ^(26)Mg) can provide novel insights into the processes that control the major ion chemistry of seawater over geologic time scales. A key period
Lithium Isotope History of Cenozoic Seawater: Changes in Silicate Weathering and Reverse Weathering
A 68-million-year record of lithium isotopes in seawater reconstructed from planktonic foraminifera reveals a stepwise change in the Li isotopic ratio, suggesting that several intense episodes of tectonic uplift increased continental weathering rates and delivery of sediments to the oceans.


Phanerozoic record of plate tectonic control of seawater chemistry and carbonate sedimentation
Sr concentrations in Phanerozoic biological calcite suggest a close link between fluctuations in the Sr/Ca ratio of seawater, aragonite versus calcite sedimentation, and the Mg/Ca ratio of seawater,
Cenozoic deep-Sea temperatures and global ice volumes from Mg/Ca in benthic foraminiferal calcite
A deep-sea temperature record for the past 50 million years has been produced from the magnesium/calcium ratio (Mg/Ca) in benthic foraminiferal calcite. The record is strikingly similar in form to
Oscillations in Phanerozoic Seawater Chemistry: Evidence from Fluid Inclusions
Systematic changes in the chemistry of evaporated seawater contained in primary fluid inclusions in marine halites indicate that seawater chemistry has fluctuated during the Phanerozoic. The
The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years
A computer model has been constructed that considers the effects on the CO/sub 2/ level of the atmosphere, and the Ca, Mg, and HCO/sub 3/ levels of the ocean, of the following processes: weathering