Time-capsule concretions: Unlocking burial diagenetic processes in the Mancos Shale using carbonate clumped isotopes

Formation mechanisms of carbonate concretions of the Monterey Formation: Analyses of clumped isotopes, iron, sulfur and carbon

Carbonate concretions can form as a result of organic matter degradation within sediments. However, the ability to determine specific processes and formation temperatures of particular concretions has remained elusive. Here, we employ concentrations of carbonate-associated sulfate (CAS), SCAS and clumped isotopes (along with more traditional approaches) to characterize the nature of concretion ...

Early Diagenetic Calcareous Coal Balls and Roof Shale Concretions from the Pennsylvanian (Allegheny Series)

The calcareous concretions studied formed in different depositional environments associated with the Pcnnsylvanian eyclothems of cast central Ohio. The late syngenetic to early diagenetie coal balls from Lower Frecport Coal in Jefferson County were formed by cellular permineralization of decaying terrestrial plants in a peat swamp. These coal balls, composed of N9.N% calcite, 7.0% pyrite, and 2...

Constraints on the formation and diagenesis of phosphorites using carbonate clumped isotopes

Dolomitization processes in hydrocarbon reservoirs: insight from geothermometry using clumped isotopes

Clumped isotopes geothermometry was applied to two dolomitic hydrocarbon reservoirs. Results indicate that late burial dolomitization occurred at ~110°C in the Albian Pinda dolostone (offshore Angola) and ~90°C in the Mano-Meillon dolostone (Aquitaine Basin, France), and did not continue on during subsequent burial/thermal evolution to present-day conditions (150160°C). This study illustrates t...

Calcium carbonate concretions formed by the decomposition of organic matter.

Bacterial decomposition of butterfish and smelts in small sealed jars containing seawater and other solutions, for periods ranging from 65 to 205 days, results in a large increase in concentrations of dissolved bicarbonate, carbonate, and ammonia (plus volatile amines). Accompanying this is a rise in pH and the precipitation of Ca(++) ion from solution. The Ca(++) is not precipitated as CaCO(3)...