The transformation of aragonite to calcite in the presence of …
网页2021年11月15日 · Data and calculations from the present study suggest that aragonite dissolution accompanied by low-Mg calcite precipitation (i.e., stabilization) is promoted by a decrease in the F:S and the development of a closed system.
Formation of Authigenic Low-Magnesium Calcite from Sites …
网页2019年4月25日 · The occurrence of primary LMC is, therefore, a good indicator of a low Mg/Ca ratio (<2) of seawater [3]. In today’s aragonite sea (an Mg/Ca ratio of seawater ~5.2; [1]), most carbonate minerals are either high-Mg calcite (HMC) or aragonite (e.g., [5, 6]).
Biogenic and abiogenic low-Mg calcite (bLMC and aLMC): …
网页2011年1月7日 · The ΣREE and shale-normalized (PAAS) REE SN values of modern brachiopods (biogenic low-Mg calcite: bLMC) represented by several species from high- to low latitudes, from shallow- to deep waters and from warm- and cold-water environments, define three distinct average ‘seawater’ trends.
Crystals structures of carbonate phases with Mg in Triassic rocks ...
网页2023年10月31日 · Magnesium is one of the components of five determined carbonate phases: low-Mg calcite (low magnesium calcite), high-Mg calcite (high magnesium calcite, magnesio-calcite)...
Element Patterns of Primary Low-Magnesium Calcite from the …
网页2020年3月27日 · High-magnesium calcite (HMC) and aragonite are metastable minerals, which tend to convert into low-magnesium calcite (LMC) and dolomite. During this process, primary compositions are frequently altered, resulting in the loss of information regarding the formation environment and the nature of fluids from which the minerals precipitated.
Magnesium-isotope fractionation during low-Mg calcite …
网页2010年8月1日 · Apparent Mg-isotope fractionation between dripwater and speleothem low-Mg calcite is about 1000lnα Mg-cc-Mg(aq) = −2.4‰. A similar Mg-isotope fractionation (1000ln α Mg-cc-Mg(aq) ≈ −2.1‰) is obtained by abiogenic precipitation experiments carried out at aqueous Mg/Ca ratios and temperatures close to cave conditions.
Massive Recrystallization of Low-Mg Calcite at High …
网页2002年7月1日 · We document massive recrystallization of low-Mg calcite lime mudstone source rocks at moderately high temperatures in the Smackover Formation of Mississippi. This process was driven by organic acids produced during kerogen maturation and holds the implications for studies of primary migration of hydrocarbons, secondary porosity generation in ...
Formation of low‐magnesium calcite at cold seeps in an …
网页2013年10月24日 · This study investigates the conditions of occurrence and petrographic characteristics of low-Mg calcite (LMC) from cold seeps of the Gulf of Mexico at a water depth of 2340 m. Such LMC mineral phases should precipitate in calcite seas rather than today's aragonite sea.
Formation of low-magnesium calcite at cold seeps in an …
网页2013年11月1日 · This study investigates the conditions of occurrence and petrographic characteristics of low-Mg calcite (LMC) from cold seeps of the Gulf of Mexico at a water depth of 2340 m. Such LMC mineral...
Diagenetic stabilization of aragonite and low-Mg calcite; I, …
网页Cretaceous rudists, with thick, multilayered, bimineralic (aragonite and low-Mg calcite) shells, have been studied for the effects of meteoric diagenesis on their textural and chemical attributes. The original fine, compact, prismatic or cellular-prismatic microstructures of low-Mg calcitic layers have been preserved frequently, despite the ...