A 2006 Geochimica et Cosmochimica Acta study used halite fluid inclusions to show that Cretaceous seawater had markedly different major-ion chemistry from the modern ocean.
More information on this topic is available in the Rock Salt Chemistry section.
Three Evaporite Regions
Researchers analysed Early Cretaceous halites from the Sergipe Basin in Brazil, Congo Basin and Khorat Plateau in Laos/Thailand.
These deposits allowed comparison across different intervals of Cretaceous seawater.
Calcium-Rich, Sulfate-Poor
The paper reported higher calcium but lower sodium, magnesium and sulfate than modern seawater.
The Mg/Ca ratio was also lower than in today’s ocean.
Tachyhydrite Connection
This chemistry may help explain rare CaCl2-bearing tachyhydrite in some Cretaceous evaporites of Brazil, Congo and Thailand.
The absence of typical modern-seawater Mg-sulfate salts in these deposits is also consistent with the reconstructed paleochemistry.
Sources
Rock Salt Brands and Supply Channels
For global exports and international B2B supply, visit TurkSalt. For retail customers in Türkiye, visit Tuzcu Baba or CankiriTuzu.com. For domestic wholesale and dealer supply, visit Berrak Tuz. For premium crystal rock-salt products, visit Kristal Tuz.