Formation of Natural Magnesium Silica Hydrate (M-S-H) and Magnesium Alumina Silica Hydrate (M-A-S-H) Cement.

ABSTRACT: Occurrences of natural magnesium alumina silicate hydrate (M-(A)-S-H) cement are present in Feragen and Leka, in eastern and western Trøndelag Norway, respectively. Both occurrences are in the subarctic climate zone and form in glacial till and moraine material deposited on ultramafic rock during the Weichselian glaciation. Weathering of serpentinized peridotite dissolves brucite and results in an alkaline fluid with a relatively high pH which subsequently reacts with the felsic minerals of the till (quartz, plagioclase, K-feldspar) to form a cement consisting of an amorphous material or a mixture of nanocrystalline Mg-rich phyllosilicates, including illite. The presence of plagioclase in the till results in the enrichment of alumina in the cement, i.e., forms M-A-S-H instead of the M-S-H

SUBMITTER: Austrheim H 

PROVIDER: S-EPMC10934351 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature